Rockweed2005

An Independent Study And Review Of The

New Brunswick Rockweed Harvest

Phase 2

by:

Beau C. Sutherland BSc.

Eastern Charlotte Waterways Inc. Blacks Harbour, NB

E5H 1E6

August 2005

Acknowledgments

I would like to thank Susan Farquharson, Lorreta Tatton, and Dan McGratten at Eastern

Charlotte Waterways Inc. (ECW) for their help in locating sample sites, the production of

figures for this report, and for offering helpful information about site locations. Thanks

to Tom MacEachreon at NB Department of Agriculture, Fisheries and Aquaculture for

providing new information on sampling protocol. Additional thanks to Susan

Farquharson for reviewing this report.

I would also like to thank Acadian Seaplants limited for allowing ECW access to the

resources for this follow up study.

2

Abstract

The harvesting of rockweed (Ascophyllum nodosum) in southern New Brunswick began

in 1995, at an exploitation level of 17%. The maximum annual harvest has just recently

been increased from the previous value of 10,000t to 11, 800t, out of a total standing crop

of 159,683t, of which 77,005t is harvestable. The annual harvest was increased because

it was found that the harvestable standing crop biomass is larger than once thought.

Harvesting of rockweed had not occurred in this area prior to 1995. The follow up study

(Phase 2) examined the differences in density, biomass and length of rockweed clumps

found in six harvested sectors using the same methodologies as the Phase 1 study.

Overall the density and overall biomass of the beds was lower and the individual clump

biomass was equal or greater than what was found in the Phase 1 study. These findings

indicate that since the Phase 1 study (1999) harvesting is having an impact on the

rockweed population, but future studies will be required to determine how extensive

these impacts are going to be in the future. A review of concerns on the impacts to the

rockweed as a result of harvesting and associated species is included in this report, along

with a brief summary of what is known regarding these topics and recommendations for

future studies.

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Table of Contents

Acknowledgements 2 Abstract 3 Table of contents 4 Section 1: Introduction 5 Section 2: Description of Rockweed 6 Section 3: Rockweed Harvesting Methods 9 Section 4: World Rockweed Industry 11 Section 5: Nova Scotia Rockweed Harvest 13 Section 6: New Brunswick Rockweed Harvest 6.1 History 15 6.2 Present Harvest 18 6.3 Contacts 19 Section 7: Eastern Charlotte Waterways Inc. Rockweed Study.

7.1 Materials and Methods 7.1.1 Study Sites 21 7.1.2 Sampling Design 22 7.1.3 Calculations 29

7.2 Results and Discussion 7.2.1 Incidence of Harvest (%clumps cut) 30 7.2.2 Density (clumps/m2) 33 7.2.3 Biomass – bed (kg/m2) 38 7.2.4 Biomass – clump (kg/m2) 43 7.2.5 Length (cm) 47 7.3 Conclusions 51 7.4 Recommendations 53 Section 8: Concerns 54 Section 9: Studies that address these concerns 55 Section 10: How Acadian Seaplants Limited Addresses these concerns 60 Section 11: Conclusions 61 Section 12: Appendix (ECW sample Locations ie: directions) 62 Section 13: References 69

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SECTION 1: Introduction

In 1995, Acadian Seaplants Limited began to harvest the untouched stands of rockweed

along the southern coast of New Brunswick at a maximum rate of 10,000t per year. That

value has just recently been increased to approximately 11,800t per year (Tom

MacEachreon per. Comm. 2005). The exploitation rate of the rockweed is still at 17%

but the overall biomass has increased resulting in a higher allowable tonnage per year.

There are still many concerns regarding the impact of harvesting on the rockweed beds

by many individuals. These concerns are exacerbated by the lack of knowledge

regarding the impact of harvesting. In the Phase 1 study (ECW 1999) there was not

enough change between the control sector and the harvested sectors to make a formal

statement regarding signs of harvesting/over harvesting of the rockweed beds. This

current study revisited the same locations five years later to determine if there are signs

of impact on the rockweed beds in the Charlotte County region. In the Phase 1 Study

Beaver Harbour was indicated as Beaver Harbour SS #4, the control site. During the

2001 harvest season this site was opened for harvest. In this current study it is referred to

as Beaver Harbour 5-9 located in Area A (Tom MacEachreon per. Comm.. 2005).

5

SECTION: 2 Description of Rockweed

Rockweed (Ascophyllum nodosum) is an intertidal seaweed found along many coasts of

the North Atlantic Ocean. It is the dominant species of seaweed in Eastern Canada, and

in some stands it can cover upwards of 100% of the substratum between the high and low

tide regions (Ugarte 1999). There is estimated to be 309,670t of rockweed in the Bay of

Fundy, 159,683t are located along Southern New Brunswick (Sharpe et al.). In Europe it

has been found that greater quantities of rockweed can be found in areas that have larger

tidal amplitudes, most likely on account of increased air exposure (Baardseth 1970).

Since the Bay of Fundy shows the largest tides in the world, it doesn’t come with much

surprise that there appears to be an abundance of rockweed along our rocky coast.

Rockweed is a multi-branching seaweed that can reach lengths of 2-3m. It is greenish-

brown in color and consists of round shoots with single air bladders punctuating the shoot

axis at regular intervals (Figure 1). The air bladders help the shoots to float in the water,

facilitating the absorption of light to run photosynthesis. The age of a rockweed clump

can be determined by counting the number of bladders on a shoot, a new bladder is

formed on the tip of a shoot each spring (Baardseth 1970). Each year the shoot grows 8-

15cm before another bladder is formed (Sharpe et al.). Rockweed primarily grows

during the spring and summer. The shoots making up a clump are anchored to a solid

substrate such as bedrock by the holdfast. Shoots can live 5-15 years, but the holdfast

can live upwards of 40 years or more (DFO 1998).

Baardseth (1970) describes the growth and reproduction cycles for rockweed found in

Norway. These cycles tend to be the same for the rockweed found in the Maritimes

(Lazo and Chapman 1996, Mathieson et al. 1976), although the exact length and timing

of each stage may be different. The male and female reproductive receptacles mature in

the spring. The receptacles bud off from the sides of the shoots and are rough in

appearance compared to the air bladders. Once the gametes are released into the water

column fertilization occurs and the zygotes settle and attach to the substratum. These

new additions to the population are easily removed by wave action and predation, which

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makes this method of reproduction very unsuccessful (Vadas and Wright 1986, Vadas et

al. 1990, Cervin and Aberg 1997). The vegetative growth is what effectively increases

the rockweed population (Baardseth 1970). Once the gametes are released the

receptacles are shed. This loss of biomass each spring accounts for a great portion of the

total rockweed biomass, ranging from 12.4 to 35.7% of the total (Cousens 1981). The

new receptacles that start to grow in the summer mature the following spring. During the

fall and winter months there is very little growth and a significant amount of biomass is

lost due to the destructive force of storms and ice scour. There is definitely seasonal

fluctuations in the biomass of rockweed, from increased biomass in the spring as a result

of growth of shoots and the reproductive receptacles, followed a decrease in biomass in

late spring when the receptacles are released, followed by continued increase in biomass

during the summer due to growth of shoots and receptacles, followed by another decrease

in biomass throughout the fall and winter caused by storms and the cessation of growth.

The rockweed that is removed from the attached population is still alive and becomes part

of the offshore floating rafts, which are used by a vast number of organisms (Ingolfsson

1998, Parsons 1986). This algae gets washed up above the high tide mark by the spring

tides and also by the highest tides each month. Bacteria, flies, and fungi decompose the

washed up algae. The following spring the tides wash the dissolved matter back into the

water column (Bradford 1989), where it is eaten by bottom dwellers and fertilizes

phytoplankton and other marine plants.

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Figure 1. Rockweed clump: A = apical tip; B = basal shoot; H = holdfast; I = internode; L = lateral shoot; P = primary shoot; R = receptacle; S = stump; V = vesicle. (taken from Sharpe 1986, Smith 2000). Definitions (Cousens 1981, Sharpe 1986) Shoot -the axis which results from growth of the apical meristem Primary Shoot-originating from the holdfast Lateral Shoot -arising from a lateral pit on another shoot Stump -a shoot lacking an apical meristem Intact Shoot -a shoot with at least one apical meristem Internode -the portion of a shoot between two adjacent vesicles Apical tip -the portion of the shoot distal of the last vesicle Clump -an assemblage of shoots arising from a common holdfast Stand -a group of clumps within a defined area Vesicles -dilations of the shoot produced at intervals related to the rate of annual elongation Receptacles -fertile lateral shoots first appearing in April-June, maturing one year and being shed in April to June. (taken from phase 1 study, Smith 2000).

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SECTION 3: Rockweed Harvesting Methods

Since rockweed has been harvested three main methods have been developed for

harvesting: 1) hand-held knives and sickles;

2) mechanical harvesters;

3) and cutter rakes.

1) Hand-held knives and sickles are used by harvesters during low tide to cut the

rockweed close to the holdfast at approximately 10cm (CAFSAC 1992). This method is

able to achieve a 90% harvest rate, and is often used to exploit the areas that cannot be

reached by other methods. Individuals can harvest 2-t per tide (Sharpe 1986). The

harvested areas are often left fallow for 3-5 years to allow regeneration (Minch Project

1999).

2) There are two types of mechanical harvesters. The Aqua Marine H650 harvester has a

reciprocating cutter blade 2.4m wide and a conveyer belt that takes the cut rockweed to a

holding area (Figure 2). The height of the blade is controlled by the operator, an average

of 35cm, and 13.6t can be harvested per day (Sharp 1981). The Norwegian suction cutter

harvester (Figure 3) draws the rockweed up into a 25cm diameter pipe where it is cut by

an impeller blade. The average cutting height controlled by the operator is 29.4cm

(Sharp 1986). This machine has an exploitation rate of 53% (CAFSAC 1992), harvesting

upwards of 50t per day. Holdfast content is 1.9% of the harvested material (Sharpe 1981).

The harvested areas are often left alone for 3-5 years to allow regeneration (Minch

Project 1999).

3) The cutter rake is a hand-held rake with sharp-edged blades in place of some of the

tines (Figure 4). The harvester maneuvers a small boat at high tide through the intertidal

zone, where the rake is dragged through the floating rockweed. Earlier style rakes had

a16% holdfast content (Sharp 1981), but the rakes used now in New Brunswick work

much better with a holdfast content of 4.7% (Ugarte and Moore 1999). Clumps are

usually cut above 25cm and because of the rake head style only a small portion of the

clump is cut. Harvesters are able to cut upwards of 4t per tide using this method.

9

In Southern New Brunswick, the cutter rake was the only harvesting tool allowed. Just

recently the use of knives on Deer Island and in the St. Martins area has been allowed for

a pilot study in 2005. This method is being used where the slope is 70 degrees or greater

and the first year there is an expected harvested of <65t. Once underway it is expected

that 5000 – 6000t could be harvested. The rockweed harvested by this method will be

added to the allowable annual harvest of 11,800t, resulting in approximately 18,000t

being harvested in the future (Tom McEachreon per. Comm. 2005).

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Figure 2. The Aqua Marine H650 (taken from Sharp 1986).

Figure 3. The Norwegian suction cutter harvester (taken from Sharp 1999a).

Figure 4. Cutter rake (taken from Sharp et al. 1999a).

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SECTION 4: World Rockweed Industry

Rockweed has been harvested around the world for centuries. It was collected for the use

as fertilizers and food (Guiry et al.1981). Today it is used as additives for animal and

human food, industrial products, fertilizer, and an extracted substance called alginate

which helps to thicken and provide consistency to many products such as cosmetics,

cheese, toothpaste, ice cream, and paint. Currently it is harvested for commercial use in

Canada, United States, Scotland, Ireland, France, Norway, and Iceland. Below is a brief

description of each of these industries, as summarized by The Minch Project (1999):

a) In the UK (Western Isles), approximately 3,000 – 4,000t/year is harvested

from a standing crop of 107,552t, resulting in a 3% exploitation rate. The

rockweed is cut year round at low tide by self employed harvesters using hand

held sickles, leaving a 15cm stump to regenerate for 3-4 years. The primary

end product is alginate.

b) In Ireland, 35,850t were harvested in 1996 (Hession et al. 1998), and it is

estimated that the present exploitation rate is 40% of the total biomass. The

rockweed is cut year round using hand held sickles, leaving a 15cm stump to

regenerate 3-4 years. Most of the rockweed is exported to Scotland for

alginate production, and the rest is made into a seaweed meal for animal

fodder and liquid extract production.

c) In France, 15,000t were harvested in 1991. An estimate of the total standing

crop or the exploitation rate could not be found. The rockweed is cut using

hand held sickles.

d) In Norway, approximately 55,000t per year has been harvested since 1965.

an estimate of the total crop or the exploitation rate could not be found. The

rockweed is harvested using both hand held sickles and mechanical harvesters,

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with a 2-6 year regeneration period. Primary products are alginate and

fertilizer.

e) In Iceland, rockweed is harvested using both hand held sickles and mechanical

harvesting. No estimates of the amount of rockweed harvested, the total

standing crop, or the exploitation rate could be found. The rockweed is

exported for alginate, animal fodder, and cosmetics.

France and Canada are the only two countries with strict regulations governing the

rockweed harvests. In France, two-yearly cutting seasons are set and strictly regulated by

the Head of Maritime Affairs. Regulations for Canada are discussed in greater detail in

the following section.

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SECTION 5: Nova Scotia Rockweed Harvest

Rockweed harvesting has occurred for many decades in Nova Scotia. In the late 1950’s,

harvesting started on the commercial level with the establishment of a processing plant

(Scotia Marine Products Ltd.) for the purpose of alginate extraction (CAFSAC 1980).

6000t per year of rockweed was processed at this plant, and under the provincial license

issued at the time harvesting was regulated only by a minimum cutting height of 12.5cm

(Sharp 1986).

The DFO Science Stock Status Report C3-57 (1998) divided the evolution of the industry

into four phases: I) a development period throughout the 1960’s where hand held knives,

sickles and cutter rakes were used for the harvesting; II) a stabilization of landings

throughout the 1970’s with the introduction of the Aquamarine harvester; III) a large

expansion period during the 1980’s due to the use of the highly effective Norwegian

harvester; and IV) a decrease in landings in the 1990’s when harvesting techniques

reverted back to hand held knives, scythes, and cutter rakes. Management guidelines and

restrictions were either non-existent or dealt with only with gear restrictions during the

first two decades of the industry development. Over harvesting occurred in many

rockweed beds along the Nova Scotia coast where competition between harvesters was

intensive. This resulted in the moving of harvesting grounds and large areas of cleared

rocks (CAFSAC 1991). Many of the areas had to be closed as a means to try and get the

rockweed populations to regenerate. In the late 1990’s, many areas were put under

exclusive license to one or two companies, which have implemented new harvesting

strategies (eg. increased cutting height, decreased exploitation rate) as a means to try and

create a sustainable harvest.

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SECTION 6: New Brunswick Rockweed Harvest

6.1 History:

In the early 1990’s, an interest in the Southern New Brunswick rockweed resource was

expressed. The rockweed population had never before been harvested, and there were

many concerns about the effects harvesting may have on the virgin state of the rockweed

in such a diverse and rich fishing area. The Canadian Atlantic Fisheries Scientific

Advisory Committee released a report in 1992 titled “Rockweed in Southwestern New

Brunswick” (CAFSAC 1992) which reviewed the information available at the time and

concluded that a carefully controlled pilot harvest could be possible if conducted in a

cautious manner. The cutter rake was the recommended harvesting tool, given a mean

cutting length of 25cm with an absolute minimum of 15cm, minimum physical disruption

of the substrate, and minimal holdfast removal were maintained. Based on harvested

conducted in other areas, the maximum recommended exploitation rate was 50%, with a

3year regeneration period. This would later translate into 17% per year. At the time it

was suggested that a conservative annual harvest of 10,000t would be acceptable,

recently this value has been increased to approximately 11,800t (Tom McEachreon Per.

Comm. 2005).

A report titled “Canada-New Brunswick Development Initiative on Rockweed

(Ascophyllum nodosum) Harvesting in the Bay of Fundy” was compiled in 1994, by the

Department of Fisheries and Oceans (DFO) and the New Brunswick Department of

Fisheries and Aquaculture (NBDFA) to establish a framework for a rockweed harvest

based on the recommendations put forth by the CAFSAC Advisory Document. This

report outlined the specific requirements to be included in any proposal to develop the

rockweed resource. These included a detailed 3year harvest plan providing projected

landings and exploitation rates, a map identifying the proposed harvest areas, the

proposed method for evaluating rockweed biomass before and after harvest, a contract

with an independent monitoring company, a description of the harvesting methods and

15

landing sites for each sector, a business plan including possible markets and method of

processing, and an education and training plan for the harvesters.

In 1995, Acadian Seaplants Limited (ASL), a company based out of Nova Scotia,

acquired the only license to harvest rockweed along the Southern coast of New

Brunswick, based on the Rockweed Fisheries Management Plan (FMP) agreement

between ASL, DFO, and NBDFA. The FMP revised the requirements laid out in the

reports described above, and added a number of refinements and amendments in order to

clarify exactly what the responsibilities of ASL were. ASL is required to provide

harvesters with an identification card stating the area and the time in which the harvest

occurred, and must provide a list of harvesters to DFO. Exclusion areas (seabird and

dulse areas) and study areas were identified where no harvesting is allowed at any point

in time. These areas are located at Point Lepreau, Cheney Passage and Cow Passage,

Musquash Harbour, Pocologan Island, Maces Bay Ledges, Pendleton Island, St. Andrews

Harbour, Great Duck Island, and Oak Bay (Appendix K and L of the FMP 1995-1997 for

detailed maps of the areas). Special Rockweed Management Areas were identified where

no harvesting is permitted between May 1st and July 1st (i.e. bird rearing areas). These

areas can be found at Maces Bay, Pocologan Harbour, Letete Passage, Mohawk Island,

Bird, Hog, and Long Islands, Dicks Island and Mill Cove, Ministers Island, Castalia,

Three Islands, Wood Island and Outer Wood Island (Appendix M in the FMP 1995-1997

for detailed maps of the areas). It was also determined that no harvesting should occur

within 200m of a herring weir after 4pm to avoid any disturbance of the herring near the

weirs. Penalties were defined for specific offences to make sure that complete

compliance with the terms of the license is being met.

Before the New Brunswick harvest got underway, Dr. Ugarte, an ASL staff scientist,

completed an intensive study of the rockweed biomass for the entire region. This study

included aerial photography, and ground truthing to provide more exact information

about the distribution and quantity of rockweed available for harvest. The findings from

this study were divided into two reports, “An Assessment of Ascophyllum

nodosum_Resources in Southern New Brunswick 1995-1996” and “Population structure

and dynamic of Ascophyllum nodosum in Southern New Brunswick”. The total licensed

16

area has been divided into three main areas: Group A (East of Deadman’s Harbour),

Group B (Passamaquoddy Bay, Letete-Letang, Deer Island, Campobello Island), and

Group C (Grand Manan).

ASL has divided these areas into sectors (see Figure 9, 10, 11 in the Phase 1 report 2000).

The total standing stock was calculated to be 159,683t and to have a total harvestable

biomass of 77,005t. The calculated biomass and annual allowable harvest for each

individual sector can be found in Tables 1-6 in the Phase 1 report (2000). Area B

contained the greatest biomass and was therefore the area of concentration for the harvest.

The pilot harvest was started in 1995 with an annual allowable harvest of 10,000t

(Table 1). The actual harvest only reached 902t, mainly on account of start-up,

equipment and training problems (DFO 1999, DFO 1998). The harvested totaled 3001t

in 1996 and 4642t in 1997. The pilot harvest resulted in a one year extension in 1998,

5781t was harvested. In 1998, the exploitation rate was only 10% which was still under

the target range of 17%.

Table 1. Yearly maximum and actual harvest amounts for each area (t). (taken from

FMP 1995-1997. 1998, DFO 1999).

Year Area A

Maximum

Area A

Actual

Area B

Maximum

Area B

Actual

Area C

Maximum

Area C

Actual

1995 3567 199 3800 703 2633 0

1996 3567 198 3800 2669 2633 134

1997 3567 255 3800 3685 2633 702

1998 1040 415 5910 4578 3050 788

Note: The data for the time period of 1999 – 2005 is considered commercially

confidential and therefore was inaccessible at the time of for this study.

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6.2 Present Harvest:

The rockweed license for ASL is renewed annually; as mentioned it had been set at

10,000t and was recently increased to approximately 11,800t for a full scale harvest. The

license is renewed yearly pending review of the previous year’s harvest. ASL has an

ongoing contract with SEEFISH, and independent certified monitoring company, which

presents the harvest data on a regular basis to DFO and also monitors the harvesting

operations. A yearly biomass assessment is conducted and the harvest limits are changed

as required. Harvesters are thoroughly trained in safety and the proper harvesting

technique, so that everyone is clear on what areas and what quantity of rockweed may be

harvested from these areas. ASL monitors the following aspects very closely: a) rakes; b)

holdfast content; c) quality of rockweed; and d0 biomass removal. Harvesting is

concentrated in sectors 6 and 7, simply because of better rockweed beds and better access

to wharves.

As the rockweed is harvested, it is loaded onto the floor of the harvester. The rockweed

is then either transported to a fixed or mobile landing site. A fixed landing site is located

on a wharf and a mobile landing site is located on a barge in areas that do not have a

wharf. Trucks then haul the rockweed to the ASL processing plant located at Pennfield

Ridge, NB. At these plants the rockweed is spread out onto an unused airfield leased by

ASL where it is dried to a specific moisture content and ground to a specific particle size.

It is then marketed as either fertilizer or a feed supplement. Scientific studies have shown

that the seaweed can increase certain aspects of plant growth and development (Crouch

1994, Blunden 1997, Poincelot 1994) and can increase milk production in cows (Nebb

and Jensen 1966). This is mainly due to the high content of vitamins and minerals in the

rockweed, things like sodium, potassium, zinc, iodine, and sulfur (Jensen 1971).

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6.2 Contacts:

Tom McEachreon

Rockweed Officer

New Brunswick Department of Fisheries and Aquaculture

P.O. Box 1037

107 Mount Pleasant Road

St. George, New Brunswick

EC 3S9

Tel: (506) 755-4000

Fax: (506) 755-4001

E-mail: [email protected]

Glyn Sharp

Department of Fisheries and Oceans

P.O. Box 1006

Dartmouth, Nova Scotia

B2Y 4A2

Tel: (902) 426-6042

Fax: (902) 426-1862


Raul Ugarte

Resource Scientist, Acadian Seaplants Limited

Tel: (506) 849-2773 (Saint John)

(506) 755-5117 (Pennfield)

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mailto:[email protected]

mailto:[email protected]

Rex Hunter

Vice President, Acadian Seaplants Limited

P.O. Box 90

Pennfield, New Brunswick

Tel: (506) 755-2004

Fax: (506) 755-2797


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SECTION 7: Rockweed Study

7.1 Materials and Methods:

7.1.1 Study Sites:

The six rockweed sectors that were originally set aside by Acadian Seaplants Limited

(Pennfield, NB) for the study conducted from August 19, 1999 to December 15, 1999

were revisited to perform a similar study from May 12, 2005 to July 25, 2005. Five of

the sectors (L’Etang 6-5, Letete 6-8, Deer Island 6-9, Digdeguash 7-5, and Chamcook 7-8)

have been harvested by ASL over the last 10 years, while Beaver Harbour SS #4 was set

aside by ASL in the beginning of the pilot harvest as a study site where harvesting was

prohibited. In 2001 Beaver Harbour was opened for harvest and is now considered

Beaver Harbour 5-9.

The current study followed the sampling method used during the Phase 1 study

conducted by Stephanie D. Smith (ECW 2000) which was described by Ugarte (1999) to

ensure the results would be comparable to industry led studies. As mentioned by

Stephanie D. Smith (2000), it was found after sampling that the methods differed in two

ways: 1) in Dr. Ugarte’s study, very thin, young clumps were not counted because they

were not considered to be harvestable where in this study all clumps over 25cm in length

were counted; and 2) in Dr. Ugarte’s study, the reproductive receptacles were removed

before the clumps were weighed because this portion of the rockweed would not be

present during harvesting (i.e. summer), where in this study no parts were removed. In

the Phase 1 study, Section 2, it was noted that this portion could amount to as much as

35.7% of the total biomass.

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7.1.2 Sampling Design:

Five to seven beds were sampled in each sector except for Letete 6-8, where 13 beds

were sampled (Figure 5, 6, 7, 8, 9, 10). Beds were chosen according to land accessibility

(See Appendix for directions to each transect in the Sectors). During low tide a transect

line was laid down from the high tide mark to the low tide mark on each rockweed bed.

10 or more 0.5m2 quadrats were placed along this transect at equal distances. Some beds

were very short compared to the length of the transect (eg. Transect = 200m, Bed = 30m),

in this case extra quadrats were added as a means to increase the sample size. Generally

7 or more quadrats were sampled per transect. A total of 383 quadrats were sampled

which gave an average of 60 quadrats per sector and 9 quadrats per transect (Table2). In

each quadrat, all rockweed clumps 25cm or greater were removed one at a time by

cutting the holdfast as close to the substrate as possible. A total of 5445 clumps were

measured. Each clump was closely inspected for any indication of harvesting, which

appear as sharply cut edges near the lower portions of the plant. The total length of each

clump was recorded. All clumps from each quadrat were placed in a net bag and

weighed to the nearest pound. The substrate type was documented and any important

observations about the beds, such as slope and degree of wave exposure were recorded as

a means to determine how similar each site is with respect to how easily it can be

accessed by the harvester’s boats (Stephanie D. Smith 2000).

Table 2 Number of samples taken in Phase 2 study.

Sector #

Transects #

Quadrats #

Uncut #

Cut Total # Clumps Lbs Kgs

Sector 5-9 6 48 717 76 793 681 309 Sector 6-5 6 48 365 305 670 641 291 Sector 6-8 13 115 1220 823 2043 1245 565 Sector 6-9 5 50 391 182 573 426 193 Sector 7-5 7 69 329 433 762 512 232 Sector 7-8 6 53 275 329 604 450.5 204 TOTAL 43 383 3297 2148 5445 3955.5 1794

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Figure 5. Beaver Harbour 5-9 sample locations.

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Figure 6. Letang 6-5 sample locations.

24

Figure 7. Letete 6-8 sample locations.

25

Figure 8. Deer Island 6-9 sample locations.

26

Figure 9 Digdeguash 7-5 sample locations.

27

Figure 10. Chamcook 7-8 sample locations.

28

7.1.3 Calculations:

Averages were calculated for each of the six sectors by compiling the quadrats sampled

in each sector that were located on the rockweed beds (including quadrats that were

empty within the beds). Including any quadrats outside the beds would have resulted in

averages below the actual value for the beds. The following values were calculated for

each sector: Incidence of Harvest (%clumps cut), Density (total # clumps/m2), Biomass

per bed (kg/ m2), Biomass per clump (kg/clump), and Length (cm). Incidence of Harvest

as described by Stephanie D. Smith (ECW 2000) is a measure of the number of cut

clumps relative to a total number of clumps. It is an indication of how many clumps are

actually affected by the harvest. It does not reflect the % biomass harvested or harvesting

rate because the amount of biomass that was removed by harvesting cannot be measured

using this method. The “biomass per clump” was calculated by dividing the weight/m2

by the density/m2. This value was used in the interpretation of the results because it was

noticed that some beds were made up of large densities of very thin, young plants, while

others had low densities of very thick, obviously mature clumps. This difference is not

apparent if one where to just look at the biomass per bed alone. Both the Incidence of

Harvest and the Biomass per Clump were calculated using only quadrats were clumps

were present. Since these values are based on the individual clump, not area, including

quadrats with no clumps present would result in averages below the actual value for the

clumps (ECW 2000).

Since the calculation of averages can often hide important trends in the population

structure, the frequency distribution was calculated for each. This essentially means that

the data was divided into size ranges or classes (eg. 0-9 clumps/m2, 10-19 clumps/m2,

etc.), and the number of quadrats that had a value within a particular class was calculated

as a percent of the total. When graphed, this tells what the more common values are and

which trends may exist, which cannot be observed simply by looking at the averages

(Stephanie D. Smith 2000).

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7.2 Results and Discussion:

7.2.1 Incidence of Harvest (% clumps cut):

As was previously mentioned in the materials and methods section, the Incidence of

Harvest is a measure of how many clumps in a sample have been cut. There is a certain

amount of error when estimating this value, because it is possible that cut shoots could

occur from other sources other than harvesting. Beaver Harbour 5-9 had a 9% Incidence

of Harvest. This is 7% higher than the study performed in 2000. The portions of plants

that were cut had an average length of 12cm, which is lower than the allowable minimum

of 25cm. The highest average value, for this phase, was in Digdeguash 7-5, where 57%

of all clumps sampled had been affected by the harvest, whereas in the Phase 1 (2000)

study it was Chamcook 7-8 which had the highest average value (Figure 12); all other

sites ranged from 32 to 54% (Figure 11). The range from the 2000 study was 10 to 30%

and this range was higher than that reported by McEachreon (1999), where there was an

Incidence of Harvest value of 17% or less for most of the transects sampled on harvested

beds, with one transect as high as 37.7%. Stephanie D. Smith (2000) concluded that this

was possibly on account of the fact the two studies did not sample the same beds.

Since a cutter rake is used for harvesting, not the entire clump is removed, and for the

most part it was observed that only 1-30% of the shoots of a clump were cut, however,

200 clumps out of 5445 sampled had greater than 80% cut. In the 2000 study conducted

by Smith it was observed that only 1-20% of the shoots of a clump were cut and only 10

clumps out of 7669 sampled had greater than 80% of the shoots cut, this was also

comparable to McEachreon’s 1999 study. In this current study the shoots in the sampled

cut clumps were counted and it was found that less than 30% of shoots on a clump had

been cut; this value is slightly higher than the 25% found in the Phase 1 study (2000).

Although it was apparent that harvesting had occurred in each of the sectors, it was not

possible to determine this by simply viewing the bed as a whole; each clump had to be

examined closely for signs of harvesting. Also, some of the sampled beds did not appear

30

to have any signs of harvesting, while others had all the clumps cut, which indicates that

the harvesters are not harvesting the sectors uniformly. This was also noticed in the 2000

study as well as by others (McEachreon 1999, Sharp et al. 1999a). It is most likely due

to variability in bed accessibility and composition. With this in mind, longer, thicker

plants are easier to harvest, and rock formations along with wave exposure may limit

movement of the boats. Sharpe et al. (1999a) calculated that the patchiness reported in

the RAP Working Paper 99/29 would result in an average exploitation rate in the patches

of 46%. This would mean that although sectors overall are harvested at 17% exploitation

rate, individual beds may be harvested at much higher rates. However, monitoring of

each individual bed is very difficult and time-consuming; this patchiness in the harvest is

regulated instead by the fact that harvesters will not generally return to a site that has

already been harvested because their catch per unit effort would decrease (Sharpe et al.

1999a).

31

Incidence of Harvest

9

45 4032

57 54

0102030405060

Bea

ver

Har

bour

5-9

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

% c

lum

ps c

ut

Figure 11. Average incidence of harvest for each sector in Phase 2 study.

Incidence of Harvest

216 17

10

30

67

01020304050607080

Bea

ver

Har

bour

SS

# 4

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

% c

lum

ps c

ut

Figure 12. Average incidence of harvest from Phase 1 study (2000).

32

7.2.2 Density (clumps/m2):

The average density of rockweed clumps within beds for the areas sampled in Southern

New Brunswick is 27 clumps/m2 (stdev = 16.4, range = 0 – 138). These values are

significantly lower than what was found by Stephanie D. Smith in the Phase 1 study

conducted in 2000, but closer to the values of 15.9 to 24.2 clumps/m2 found by Dr.

Ugarte (Ugarte and Moore 1999). These values compared to other areas are much lower.

In Rhode Island, U.S.A, average density in the study site was 91 clumps/m2 (Peckol 1988)

and in Maine, U.S.A, average density in the study site was 390 clumps/m2 (Keser et al.

1981); however, as Smith (2000) indicated in her study these earlier studies counted all

clumps in the quadrats, not just those over 25cm.

Beaver Harbour 5-9, which was once the control site, where harvesting was prohibited,

had an average density of 33 clumps/m2 (Figure 13). As in the Phase 1 study (ECW 2000)

four of the five harvested sectors had average densities lower than Beaver Harbour 5-9.

Letete 6-8 had an average density that was slightly higher than Beaver Harbour 5-9 due

to the significant number of very thin, young plants >25cm. This situation in Letete is

said not to be a result of the harvesting taking place because it was observed long before

harvesting had begun (Stephanie D. Smith. 2000).

The frequency distribution for each sector can be seen in Figure 14. It appears that most

of the harvested sectors have density distributions shifted to the left, or to the lower

density classes, compared to Beaver Harbour 5-9. These same results were also found in

the Phase 1 study. The importance of examining the frequency distribution is best

illustrated by the data from Deer Island, where the average density was 23 clumps/m2 but

the greatest portion of individual density values was in the 30-39 clumps/m2 class.

It has been shown in other instances that other factors influence density, such as wave

exposure and substrate type (Vadas and Wright 1986, Baardseth 1970), and although the

sectors studied had generally the same environmental conditions, they were not identical.

In comparison to Figure 14 which shows the density frequency distribution for the phase

33

1 study (ECW 2000) it can be observed that the harvest in conjunction with natural

systems may be impacting on the rockweed. In all sectors excluding Digdeguash 7-5,

which has increased, density values have decreased. Future studies will be required to

determine a rate of decrease and how significant the impact of harvesting may be having

on the rockweed beds in Southern New Brunswick.

34

Density33 28

3523 22 23

010203040

Bea

ver

Har

bour

5-9

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

Tota

l # c

lum

ps/m

^2

Figure 13. Average density for each sector in Phase 2 study.

35

Beaver Harbour 5-9

05

1015202530

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clump/m2)

Freq

uenc

y (%

)

Letang 6-5

05

101520253035

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clumps/m2)

Freq

uenc

y (%

)

Average = 40 Stdev. = 19 n = 48 Average = 28 Stdev. = 13 n = 48

Letete 6-8

05

1015202530

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clumps/m2)

Freq

uenc

y (%

)

Deer Island 6-9

05

101520253035

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clumps/m2)

Freq

uenc

y (%

)


Digdeguash 7-5

05

1015202530

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clumps/m2)

Freq

uenc

y (%

)

Chamcook 7-8

05

1015202530

0-9

10--1

9

20--2

9

30--3

9

40--4

9

50--5

9

60--6

9

70--7

9

80--8

9

90--9

9

100+

Class (clumps/m2)

Freq

uenc

y (%

)


Figure 14. Density frequency distribution for each sector in the Phase 2 study.

36

Beaver Harbour SS # 4

01020304050

Class (clumps/m2)

Freq

uenc

y (%

)

Letang 6-5

01020304050

Class (clumps/m2)

Freq

uenc

y (%

)

Average = 44 Stdev = 15 n = 48 Average = 30 Stdev = 17 n = 48

Letete 6-8

01020304050

Class (clumps/m2)

Freq

uenc

y (%

)

Deer Island 6-9

01020304050

Class (clumps/m2)

Freq

uenc

y (%

)


Digdeguash 7-5

0102030

4050

Class (clumps/m2)

Freq

uenc

y (%

)

Chamcook 7-8

010

2030

4050

Class (clumps/m2)

Freq

uenc

y (%

)


Figure 15. Density frequency distributions for each sector in the ECW study from Phase 1 (Smith 2000).

37

7.2.3 Biomass – bed (kg/m2):

The average biomass of rockweed beds in the areas sampled in Southern New Brunswick

is 10.5 kg/m2 (stdev = 6.0, range = 0.0 – 41.7). Similar biomass averages were reported

in the Phase 1 study conducted in 2000. The average biomass then was reported to 10.7

kg/m2 (stdev = 7.3, range = 0.0 – 40.0) (Smith 2000). Dr. Ugarte reported similar

biomass averages for Southern New Brunswick of 8.3 to 10.8 kg/m2 (range = 0.1 – 37.0)

(Ugarte and Moore 1999).

Beaver Harbour 5-9 had an average bed density of 12.9 kg/m2 (Figure 16). Beaver

Harbour, as a prohibited harvest area, in the Phase 1 study had an average bed density of

12.0 kg/m2. The harvested sectors did not vary greatly from this value, except Deer

Island 6-9, Digdeguash 7- 5, and Chamcook 7-8, which had average bed densities of 7.7,

6.7 and 7.7 kg/m2 respectively. Upon examination of the frequency distributions it does

appear that there are some differences between the harvested sectors and Beaver Harbour

which was once closed (Figure 17). There were more quadrats with low biomass in the

harvested sectors than in Beaver Harbour, as was found in Figure 24 of the Phase 1 study

(Smith 2000) (Figure 18). All of the sectors showed averages that were higher than the

most frequent size class.

Again, it can be said that the rockweed harvest may be having a ‘reducing effect’ on the

biomass of the beds. Other factors such as wave exposure may also be having a natural

impact on the biomass of the beds (Vadas and Wright 1986, Cousens 1981, Cousens

1982). A series of more frequent studies will be required to determine the extent of the

impact of harvesting on the rockweed beds. Unlike the Phase 1 study where the sector

with the highest Incidence of Harvest had similar average bed density, the sector with the

highest Incidence of Harvest had the lowest average bed density. This may be some

indication that harvesting is impacting the rockweed beds. When the frequency

distributions are compared, it can be shown that the sectors are different compared to the

Phase 1 study. This may indicate that a change in the population structure is occurring.

38

It should be noted that the Phase 1 study was conducted in (Aug – Dec), while this study

was conducted from (May – July). This study was performed on the harvestable biomass

for the summer. The values recorded are not higher like some may expect due in part that

sampling was done just after the winter effcts and before the new growth had started.

Providing all factors are considered, it should be possible to compare the six sectors

during the same time period. Further studies will be required to eliminate any

speculation of the yearly cycles of biomass increase or decrease.

39

Biomass (bed)12.9 12.1

9.87.7 6.7 7.7

02468

101214

Bea

ver

Har

bour

5-9

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

kg/m

^2

Figure 16. Average biomass of the beds for each sector in the ECW study.

40

Beaver Harbour 5-9

0

5

10

15

200-

2.4

2.5-

4.9

5.0-

7.4

7.5-

9.9

10.0

-12.

4

12.5

-14.

9

15.0

-17.

4

17.5

-19.

9

20.0

-22.

4

22.5

-24.

9

25.0

+

Class (kg/m2)

Freq

uenc

y (%

)Letang 6-5

010203040

0-2.

42.

5-4.

95.

0-7.

47.

5-9.

910

.0-1

2.4

12.5

-14.

915

.0-1

7.4

17.5

-19.

920

.0-2

2.4

22.5

-24.

925

.0+

Class (kg/m2)

Freq

uenc

y (%

)

Average = 15.8 Stdev. = 8.3 n = 39 Average = 11.2 Stdev. = 5.5 n = 48

Letete 6-8

05

1015202530

0-2.

4

2.5-

4.9

5.0-

7.4

7.5-

9.9

10.0

-12.

4

12.5

-14.

9

15.0

-17.

4

17.5

-19.

9

20.0

-22.

4

22.5

-24.

9

25.0

+

Class (kg/m2)

Freq

uenc

y (%

)

Deer Island 6-9

05

10152025

0-2.

4

2.5-

4.9

5.0-

7.4

7.5-

9.9

10.0

-12.

4

12.5

-14.

9

15.0

-17.

4

17.5

-19.

9

20.0

-22.

4

22.5

-24.

9

25.0

+

Class (kg/m2)

Freq

uenc

y (%

)


Digdeguash 7-5

01020304050

0-2.

42.

5-4.

95.

0-7.

47.

5-9.

910

.0-1

2.4

12.5

-14.

915

.0-1

7.4

17.5

-19.

920

.0-2

2.4

22.5

-24.

925

.0+

Class (kg/m2)

Freq

uenc

y (%

)

Chamcook 7-8

05

101520253035

0-2.

4

2.5-

4.9

5.0-

7.4

7.5-

9.9

10.0

-12.

4

12.5

-14.

9

15.0

-17.

4

17.5

-19.

9

20.0

-22.

4

22.5

-24.

9

25.0

+

Class (kg/m2)

Freq

uenc

y (%

)


Figure 17. Biomass (bed) frequency distribution for each sector in the Phase 2 study.

41

Beaver Harbour SS #4

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)Letang 6-5

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)

Average=12.8 Stdev=5.5 n=45 Average=12.6 Stdev=7.4 n=48

Letete 6-8

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)

Deer Island 6-9

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)


Digdeguash 7-5

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)

Chamcook 7-8

05

1015202530

Class (kg/m2)

Freq

uenc

y (%

)


Figure 18. Biomass (bed) frequency distribution for each sector in the Phase 1 study (Smith 2000).

42

7.2.4 Biomass – clump (kg/clump):

During sampling, it was noticed that some sectors contained a greater portion of large,

multi-branching clumps, whereas other sectors were made up mostly of smaller, thinner

clumps (Figure 19). As in the Phase 1 study, Letete had the lowest biomass per clump at

only 0.3 kg/clump, this is slightly higher than the 0.2 kg/clump that was found in the

earlier study, whereas Digdeguash 7-5 and Letang 6-5 averaged 0.5 kg/clump. From the

previous study to the present the average increased for Beaver Harbour 5-9 and Letete 6-

8, and decreased for the remaining sectors in the study. The thinner clumps were

observed to be young, with few shoots formed rather than older, with the majority of

shoots removed by harvesting. It is a strong possibility that harvesting may have

contributed to the reduction or complete removal of the older established clumps,

enabling new growth to occur. Digdeguash 7-5 had the highest Incidence of Harvest as

mentioned earlier and it also had the highest biomass (kg/clump). With this in mind,

there does not appear to be any connection with Incidence of Harvest and clump biomass

at this time. The frequency distribution revealed that four of the five harvested sectors

either had the same or greater range of clump biomass compared to sixth sector Beaver

Harbour 5-9 (Figure 20), similar findings were found in Figure 26 of the Phase 1 study

(ECW 2000) (Figure 21). As mentioned earlier the sector with the highest Incidence of

Harvest (Digdeguash 7-5) also had one of the highest average clump biomasses. An

explanation for this is may be that harvesting stimulates growth and the formation of new

shoots, increasing the complexity and biomass of the clump (Boaden and Fring 1980,

Lazo and Chapman 1996).

43

Biomass (clump)

0.40.5

0.30.4

0.50.4

00.10.20.30.40.50.6

Bea

ver

Har

bour

5-9

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

kgs/

clum

p

Figure 19. Average biomass of the clumps for each sector in the Phase 2 study.

44

Beaver Harbour 5-9

0

5

10

150.

20.

30.

40.

50.

60.

7 80.

9 11.

11.

21.

3+

Class (kg/clump)

Freq

uenc

y (%

)Letang 6-5

0

5

10

15

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1

1.1

1.2

1.3+

Class (kg/clump)

Freq

uenc

y (%

)


Letete 6-8

01020304050

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1

1.1

1.2

1.3+

Class (kg/clump)

Freq

uenc

y (%

)

Deer Island 6-9

0

5

10

15

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1

1.1

1.2

1.3+

Class (kg/clump)

Freq

uenc

y (%

)


Digdeguash 7-5

05

10152025

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.1

1.2

1.3+

Class (kg/clump)

Freq

uenc

y (%

)

Chamcook 7-8

05

101520

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9 1

1.1

1.2

1.3+

Class (kg/clump)

Freq

uenc

y (%

)


Figure 20. Biomass (clump) frequency distribution for each sector in the ECW study.

45


0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)

Letang 6-5

0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)


Letete 6-8

0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)

Deer Island 6-9

0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)


Digdeguash 7-5

0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)

Chamcook 7-8

0

10

20

30

40

50

Class (kg/clump)

Freq

uenc

y (%

)


Figure 21. Biomass (clump) frequency distribution for each sector in the Phase 1 study (Figure 26 Smith 2000).

46

7.2.5 Length (cm):

The average length didn’t vary significantly across all of the sectors, ranging from 63 cm

to 78 cm (Figure 22). This range is lower than was found in the Phase 1 study (range 64

cm to 92 cm) (Smith 2000). These new values are still very much similar to those found

by Dr. Ugarte, despite the different methodologies, where the average length ranged from

57.5 cm to 80.5 cm (Ugarte and Moore 1999). The frequency distributions were also

very similar (Figure 23). The longest clump record was 189 cm, found in Chamcook 7-8,

which also had the longest average length in the Phase 1 study (Smith 2000). As was

mentioned in the Phase 1 study and noted at the time of sampling for this study, the

intertidal zone at Chamcook is distinct in that the high tide mark tends to be

approximately 1m up the face of a small cliff and there is not much of a slope. This

implies that at high tide the clumps located near the high tide mark would be less than 1m

of water allowing them to grow longer than in other sectors. As stated Chamcook had

one of the highest Incidences of Harvest along with Digdeguash, this may be an

indication of a relationship between Length and Incidence of Harvest. It is likely that

harvesters prefer to harvest beds with longer clumps because it is easier. In the Phase 1

study it was observed that the cut clumps on average were longer than the uncut clumps

(Smith 2000). In this current study this distinction is not as obvious, both the cut and

uncut are similar in length. Some of the sectors had an average cut length that was longer

than the uncut where the opposite was observed in other sectors. Four of the five sectors

had average lengths lower than Beaver Harbour indicating that harvesting may be

affecting the average length of clumps in the stand. By comparing Figure 23 to Figure 24

(Smith 2000) it can be noticed that the length of the clumps in each sector has dropped

giving a lower average clump length.

47

Length

0102030405060708090

Bea

ver

Har

bour

5-9

Leta

ng 6

-5

Lete

te 6

-8

Dee

r Isl

and

6-9

Dig

degu

ash

7-5

Cha

mco

ok7-

8

Sector

Ave

rage

Len

gth

(cm

)

allcutuncut

Figure 22. Average length for the sectors in the ECW study.

48

Beaver Harbour 5-9

05

1015

20

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)

Letang 6-5

02468

10121416

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)


Letete 6-8

0

5

10

15

20

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)

Deer Island 6-9

0

5

10

15

20

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)


Digdeguash 7-5

0

5

10

15

20

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)

Chamcook 7-8

05

1015

20

25-3

435

-44

45-5

455

-64

65-7

475

-84

85-9

495

-104

105-

114

115-

124

125-

134

135-

144

145+

Class (cm)

Freq

uenc

y (%

)


Figure 23. Length frequency distribution for each sector in the Phase 2 study.

49


0

5

10

15

20

Class (cm)

Freq

uenc

y(%

)

Letang 6-5

0

5

10

15

20

Class (cm)

Freq

uenc

y (%

)

Average=69 Stdev= 24 n=1061 Average=69 Stdev=29 n=726

Letete 6-5

0

5

10

15

20

Class (cm)

Freq

uenc

y (%

)

Deer Island 6-9

0

5

10

15

20

Class (cm)

Freq

uenc

y (%

)

Average=64 Stdev=24 n=3942 Average=69 Stdev=25 n=692

Digdeguash 7-5

0

5

10

15

20

Class (cm)

Freq

uenc

y (%

)

Chamcook 7-8

0

5

10

15

20

Class (cm)

Freq

uenc

y (%

)

Average=72 Stdev=25 n=278 Average=93 Stdev=34 n=702

Figure 24. Length frequency distribution for each sector in the Phase 1 study (Figure 28. Smith 2000)

50

7.3 Conclusions:

Upon normal inspection before examining the individual clumps closely it was difficult

to observe any negative effects on the rockweed beds as a result from harvesting.

However, upon closer inspection differences between the six sectors sampled in this

study and the Phase 1 study when specific parameters are measured can be observed:

1. Average density was lower in all but one of the sectors and higher in the other

when this study is compared to the Phase 1 study.

2. Average bed biomass was lower in three of the six sectors when this study is

compared to the Phase 1 study

3. Average clump biomass was lower in one of the six sectors, the same in one and

higher in four when this study is compared to the Phase 1 study.

4. Average length was higher in three of the six sectors when this study is compared

to the Phase 1 study.

Harvesting pressure in the sectors was not found to be constant throughout or between

sectors. The sector average Incidence of Harvest ranged from 32% to 57%. The highest

Incidence of Harvest occurred in Digdeguash, where the highest biomass (clump) was

found. At this point it can be said from the results of this study compared to the Phase 1

study that the rockweed beds have changed in all of the following categories: density,

biomass, clump biomass, and average length. Compared to the Phase 1 study it was

found that the percentages in all the above-mentioned categories have decreased by 3-5%.

Physical differences between the sites may account for some of the differences noted.

This current study showed that all but one of the harvested sites had a lower density,

while one was higher than Beaver Harbour; all of the prior harvested sites had a lower

bed biomass. Clump biomass was only lower in one of the harvested sites and the same

as or higher than Beaver Harbour in the other four harvested sites, but once again, multi-

year studies are required to determine the actual effects each year caused to the rockweed

beds by harvesting. There is little known about the extent winter storms and other

processes decrease the biomass or to what extent reproductive growth increases the

biomass throughout the season. Given that these processes are most likely very similar

51

year to year, a multi-year study conducted within the same time frame would provide

important information relevant to any differences as a result of the harvest year to year.

52

7.4 Recommendations:

It was found in this study that the rockweed harvest may be contributing on the rockweed

beds. With that said it is important to give an indication on what the current situation is

and where future studies should focus their attention. It is recommended that a similar

study be repeated with no changes to the methodology at least another one or two more

times on a shorter time scale to determine the exact effect of the harvest to the rockweed

beds. As mentioned in the Phase 1 study a more detailed analysis of the individual clump

structure should be performed. This would involve bringing the individual clumps back

to the lab where the age and structure of each cut and uncut clump could be determined.

This would give a clearer picture of clump biomass and may indicate why there is such a

difference between the sectors. It would also be interesting to know how different

substrates affect the population dynamics and what relationship there is between the

lengths of the clumps to the depth of the water is.

In future studies the access to data would be relevant when conducting third party audits.

All relevant data should be accessible by the public when concerns arise.

53

SECTION 8: Concerns

1) Is there any chance of overharvesting, as was seen in Nova Scotia?

2) To what extent are fish associated with rockweed and how might they be affected

by the harvest?

3) To what extent are invertebrates associated with rockweed and how might they be

affected by the harvest?

4) What other organisms are associated with rockweed which might be affected by

the harvest?

5) Will the harvest remove significant amounts of invertebrates in the by-catch?

54

SECTION 9: Studies that address these concerns

1) Is there a chance of overharvesting, as was seen in Nova Scotia?

Rockweed populations, if given enough time between harvests, can recover even when

most of the biomass is removed, so long as there is adequate plant material left for new

shoot growth (Keser et al. 1981, CAFSAC 1992, Baardseth 1970, Sharp 1986). With this

said overharvesting can still result in the loss of an entire population on account of the

low survival rate of the young plants (Baardseth 1970, Vadas and Wright 1986, Vadas et

al. 1990, Cervin and Aberg 1997). The two main reasons behind the overharvesting in

Nova Scotia were: a) the use of the mechanical harvester; and b) the lack of exclusive

licenses. In New Brunswick, these two factors do not really come into play because the

cutter rake and now the knife on Grand Manan are the only two methods allowed, and

Acadian Seaplants Limited has an exclusive license for the Southern New Brunswick

rockweed resource. The harvesting rate for the area is 17%, which is very low in

comparison to Nova Scotia where the harvesting rate was upwards of 90%.

The study completed in 2005 for Eastern Charlotte Waterways Inc. and described in this

report in Section 7 showed that after 10 years of harvesting, the sampled rockweed beds

have showed decreases in all of the parameters studied. Upon examination of the

quantitative data, there did appear to be some differences with regards to density,

biomass, and length when compared to the study conducted in 2000 by Stephanie D.

Smith. However, at this time there are signs of harvesting, more so than the Phase 1

study but none that can indicate overharvesting.

55

2) To what extent are fish associated with rockweed and how might they be affected

by the harvest?

There has been a lot of concern raised surrounding the potential impact of a rockweed

harvest on commercial fish species that use the intertidal habitat during the juvenile

stages. A review was given on the current knowledge available about fish and their use

of the rockweed habitat (Rangley 1999). In the Passamaquoddy Bay, NB, 31 species of

fish have been noted in the intertidal zone, such as winter flounder, Pollock, and Atlantic

herring, with an average of 18 species per site. Juvenile Pollock were studied in Southern

New Brunswick by using seine nets and visual transects taken by SCUBA divers

(Rangeley and Kramer 1995a, b). The study showed that in open waters the Pollock

formed schools while in the protection of the rockweed habitat they dispersed

individually. These are anti-predator tactics, which help protect the fish from birds and

other predatory fish. The Pollock preferred dense habitat as opposed to sparse habitat.

56

3) To what extent are invertebrates associated with rockweed and how might they be

affected by harvest?

Throughout the course of the ECW study, a great number of invertebrates were observed

within the rockweed beds at low tide, such as periwinkles, crabs, and limpets. These

invertebrates may act as predators or prey. There have been a number of studies

conducted to determine the abundance of various invertebrates, and the most common

conclusion is that there is a high degree of variability in the densities and distributions

(Johnson and Scheibling 1984). Greater abundances of invertebrates can be found in

areas with rockweed as opposed to those without (Sharp et al. 1999b). The degree of

clump complexity is related to invertebrate densities, based on the number of niches

available. Turnover is very high for invertebrates found in the canopy, due to high

reproductive capacities and short life spans, which allows for quick recovery when the

population is disturbed. Two studies have been conducted in Ireland and Maine, U.S.A.,

which looked at the effects of harvesting on invertebrate abundance (Boeden and Dring

1980, Fegley et al. 1999). It was found that some invertebrate densities decreased after

harvesting. Since the Southern New Brunswick harvest is much lower than in these other

two areas it is hard to determine whether or not harvesting is having or will have an effect

on the invertebrate populations.

57

4) What other organisms are associated with rockweed and how might they be

affected by the harvest?

Epiphytes are plants that grow on other plants. The epiphyte Polysphonia Ianosa is one

epiphyte that grows on rockweed and has been found to have higher densities on

damaged shoots (Lobban and Baxter 1983). Epiphytes often are a food source for

invertebrates. The effect of harvesting on these relationships is not known at the present

time. Microalgae, microorganisms, fungi, may also be associated with rockweed. One

study showed that colonizing algae were greater in abundance and diversity beneath a

canopy of rockweed than in uncovered sites (Hruby and Norton 1979).

58

5) Will the harvest remove significant numbers of invertebrates in the by-catch?

There is a possibility of invertebrates being caught as a by-catch in the Southern New

Brunswick harvest because any organism on the rockweed shoots are subject to being

pulled into the harvester’s boat along with the rockweed. The by-catch has been

monitored by NBDFA between 1996 and 1998 and is an ongoing part of the yearly

monitoring conducted by NBDFA. The number of individuals/kg of rockweed for various

species of invertebrates ranged from 0 to 229 over the three-year study period

(McEachreon 1999). The by-catch varied depending on the sector and the season.

For more concerns as a result of the rockweed harvest in Southern New Brunswick see

the Phase 1 Study Report conducted by Eastern Charlotte Waterways Inc.

59

SECTION 10: How Acadian Seaplants Limited addresses these concerns

Harvesters are monitored very closely by ASL in regards to when, where, and how much

is allowed to be harvested. Sectors are designated closed once the annual allowable

harvest has been met. Yearly biomass assessments are performed in order to determine

the annual allowable harvest for the next year. Exclusion and study sites are set aside

where absolutely no harvesting is to take place, and Special Rockweed Management

Areas are closed to harvesting during certain seasons. ASL is willing to change the status

of areas depending on conservation issues that may arise. Any harvester found in closed

sectors is terminated immediately. ASL provides training in safety and harvesting

technique. Cutter rakes are checked every week and replaced if the cutting surface is dull.

Holdfast content is monitored every day at the landing sites, and any areas showing

unacceptable levels of holdfast content (> 10%) are given reduced quotas or are closed

completely.

60

SECTION 11: Conclusions

The harvesting of rockweed in Southern New Brunswick does not appear to be having an

effect on the rockweed population but there are noticeable impacts occurring as a result

of the harvest. These impacts include a decrease in the overall length of the rockweed,

biomass has decreased in all sectors except Beaver Harbour where it has increased, and

the density has decreased in all sectors except in Chamcook where it has increased. The

maximum exploitation rate of 17% is on a small enough scale that if any dramatic

changes occur, they will be able to detect it immediately. There is a considerable lack of

knowledge regarding the organisms associated with the rockweed habitat, their

interactions, and the effects of a harvest on both. This rockweed harvest should be

viewed more comprehensively as a large experiment which is monitored on as many low

tides as possible providing scienctist the time to observe immediate impacts, if any the

harvest may be having on the different organisms.

Section 12 of the Phase 1 study listed recommendations for follow-up studies.

61

SECTION 12: Appendix (sample locations)

Sector 5-9 Beaver Harbour:

Transect # 1: Take route 778 to Beaver Harbour (off # 1 Highway) Follow route through small town Turn left onto Lighthouse Road Road goes all the way to lighthouse but is blocked by a gate, so park by Gate and walk up to lighthouse Transect taken on beach to the left of lighthouse Transect # 2: Take route 778 to Beaver Harbour ( off # 1 Highway) Follow route through small town Turn left onto Lighthouse Road Use house # 23 as an access point Transect taken on second rockweed bed to the left (past rock outcropping) Transect # 3: Take route 778 to Beaver Harbour (off # 1 Highway) Follow route through small town Park across from house # 10 Transect taken on beach directly ahead Transect # 4: Take route 778 to Beaver Harbour (off # 1 Highway) Turn left onto Eldridge Road Turn right onto Eldridge ext. Park near house # 6 Use small dirt road for access to beach Transect taken on beach to the right Transect # 5: Take route 778 to Beaver Harbour (off # 1 Highway) Turn left onto Waites Lane Park near house # 9 Walk down small path at rear of property (goes all the way to beach) Transect taken on beach to the right (near point) Transect #6: Take route 778 to Beaver Harbour (off # 1 Highway) Turn left onto Munroe Road Turn right onto Woodland Road Turn left onto Foleys Cove Road (dirt road) Use salmon hatchery property as an access point Transect taken on beach to the left

62

Sector 6-5 Letang Harbour: Transect # 1: Take route 172 towards Deer Island Turn left onto Limekiln Road Turn left onto Granitefield Road (private) Turn right onto an unmarked gravel road that goes to an aquaculture site Transect taken on the beach to the left Transect # 2: Take route 172 towards Deer Island Turn left onto Limekiln Road Turn left onto Artemus Hatt Road Park near house # 106 Use path between houses for access to beach Transect taken on beach straight ahead Transect # 3: Take route 172 towards Deer Island Park near house # 412 (on main road) Use path at rear of property for access to beach Transect taken on beach directly ahead Transect # 4: Turn right onto Mealey Road (off # 1 Highway) Turn right onto Justason’s corner Turn right onto Lewis Road Road goes all the way to beach Transect taken on beach to the left Transect # 5: Take route 776 towards Blacks Harbour Turn right onto Nason St. Park near house # 100 Transect taken on beach below house Transect # 6: Take route 776 towards Blacks Harbour Turn right onto Wellington Road Turn right onto Greenlaw Road Park across from house # 161 Transect taken on beach to the left (on point)

63

Sector 6-8 Letete:

Transect # 1: Take route 172 towards Deer Island Park at Deer Island Ferry Terminal. Transect taken on beach to the left. Transect # 2: A small boat is needed to reach this transect site. Take route 172 towards Deer Island Launch boat from Deer Island Ferry Terminal. Transect taken on seaward side of intertidal island. Transect # 3: Take route 172 towards Deer Island Turn left onto Greens Point Road Turn right onto Branch 3 Road (goes all the way to the shore) Transect taken on beach to the right (around the bend) Transect # 4: Take route 172 towards Deer Island Turn left onto Greens Point Road Turn right onto Branch 3 Road (goes all the way to the shore) Transect taken on beach point straight ahead Transect # 5: Take route 172 towards Deer Island Turn left onto Greens Point Road Turn right onto Branch 3 Road (goes all the way to the shore) Transect taken on beach to the left (around the bend) Transect # 6: Take route 172 towards Deer Island Turn left onto Greens Point Road (goes all the way to the shore) Transect taken on beach to the left Transect # 7: Take route 172 towards Deer Island Turn left onto Greens Point Road (goes all the way to the shore) Transect taken on beach point near lighthouse Transect # 8: Take route 172 towards Deer Island Turn left onto Greens Point Road (goes all the way to the shore) Transect taken on beach to the left below cottage (around the bend)

64

Transect # 9: Take route 172 towards Deer Island Turn left onto Greens Point Road (goes all the way to the shore) Transect taken on beach to the left (past cobble beach) Transect # 10: Take route 172 towards Deer Island Go straight at Back Bay Turn left onto Madison Road Turn right onto Back Bay Cemetery Road Road ends at Crow Island Fisheries aquaculture site Transect taken on beach to the right (on point) Transect # 11: Take route 172 towards Deer Island Go straight at Back Bay Turn left onto Madison Road Turn right onto Back Bay Cemetery Road Road ends at Crow Fisheries aquaculture site Transect taken on beach to the right Transect # 12: Take route 172 towards Deer Island Go straight at Back Bay Turn left onto Back Bay Loop (follows shore) Transect taken on beach to the right Transect # 13: Take route 172 towards Deer Island Go straight at Back Bay Turn left onto Madison Road (goes all the way to the shore) Transect taken on beach to the right (below large cottage)

65

Sector 6-9 Deer Island: Transect # 1: Take route 172 to Deer Island Park near Deer Island Ferry terminal Transect taken on beach to the right of ferry terminal Transect # 2; Take route 172 to Deer Island Park across from house # 32 Transect taken on beach to the right Transect # 3: Take route 172 to Deer Island Turn left onto Leaman Road Turn left onto Calder Road Park on side of road Transect taken on beach to the left (around point; below A frame house) Transect # 4: Take route 172 to Deer Island Turn left onto Leaman Road Park near Piskahegan’s Kayak Shack Transect taken on beach to the right (on point) Transect # 5: Take route 172 to Deer Island Turn left onto Leaman Road Park across from House # 90 Transect taken on beach to the right

66

Sector 7-5 Digdeguash: Transect # 1: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Holts Point Road (turns into dirt road) Road goes all the way to beach Transect taken on beach to the left Transect # 2: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Fiander Road (turns into dirt road) Road goes all the way to beach Transect taken on beach to the left past the small point Transect # 3: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Fiander Road (turns into dirt road) Take Glass Point Road (ends on private property) Transect taken on beach to the right Transect # 4: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Fiander Road (turns into dirt road) Take Glass Point Road (ends on private property) Transect taken on beach to the left Transect # 5: Turn left onto Spur # 2 Road Road ends at old bridge Transect taken on beach to the left Transect # 6: Turn left onto Spur # 2 Road Turn left onto Flynn Road Road ends on private property (BEWARE of dog!!) Transect taken on beach to the left Transect # 7: Turn left onto Oven Head Road (off # 1 Highway) Turn right onto unmarked dirt road after house # 108 Road ends on private property Transect taken on beach to the right

67

Sector 7-8 Chamcook: Transect # 1: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Road Turn left onto road leading to aquaculture landing site Transect taken on beach to the left Transect # 2: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Road Turn left onto the Anning’s Property (#292) Transect taken on beach to the left Transect # 3: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Road Turn left onto unmarked private road Transect taken on beach to the left Transect # 4: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Road Turn left onto Birch Cove View Road (private road) Transect taken on beach below houses Transect # 5: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Road Park on side of road across from house # 485 Transect taken on beach straight ahead Transect # 6: Take route 127 towards St. Andrews (off # 1 Highway) Turn left onto Glebe Park on side of road across from house # 535 Walk to beach on other side of small stream Transect taken on beach around the point

68

SECTION 13: References

Baardseth, E. 1970. Synopsis of biological data on knobbed wrack Ascophyllum

nodosum (Linnaeus) Le Jolis. FAO Fisheries Snopsis 38.

CAFSAC 1980. Items from Invertebrates and Marine Plants Subcommittee meeting

CAFSAC Advisory Document 80/5.

1991. Rockweed. CAFSAC Advisory Document, 91/10

1992. Rockweed in Southwestern New Brunswick. CAFSAC Advisory

Document 92/13 Cervin, Gunner, and Per Aberg. 1997. Do littorinids affect the survival of Ascophyllum

nodosum germlings? J. Exp. Mar. Biol. And Ecol. 218:35-47.

Cousens, R. 1981. Variationin annual production by Ascophyllum nodosum (L.) Le Jolis

with degree of exposure to wave action. Proc. Int. Seaweed Symp. 10: 253-258.

1982. The effect of exposure to wave action on the morphology and pigmentation

of Ascophyllum nodosum (L.) Le Jolis. J. Exp. Mar. Biol. Ecol. Vol. 92: 231-249.

DFO 1998. Rockweed (Ascophyllum nodosum). DFO Sci. Stock Status Rep. C3-57

(1998)

DFO 1999. The impact of the Rockweed Harvest on the Habitat Structure of Southwest

New Brunswick. DFO Maritimes Regional Habitat Status Rep. 99/2E.

DFO and NBDFA. 1994. Canada-New Brunswick Development Initiative on Rockweed

(Ascophyllum nodosum) Harvesting in the Bay of Fundy

69

Fishery Management Plan: Rockweed-Southwestern New Brunswick. 1995-1997, 1998.

A Fisheries co-Management Agreement between Acadian Seaplants Limited,

DFO, and NBDFA.

Guiry, M.D. & Blunden, G. 1981. The commercial collection and utilization of seaweeds

in Ireland. Proceedings of the International Seaweed Symposium, 10: 675-680.

Ingolfsson, Agnar. 1998. Dynamics of macrofaunal communities of floating seaweed

Clumps off Iceland: a study of patches on the surface of the sea. J. Exp. Mar.

Biol. Ecol 231: 119-137.

Jensen, Arne. 1971. The nutritive value of seaweed meal for domestic animals. Proc.

of 7th Intern. Seaweed Symp. P7-14

Keser, M., R.L. Vadas, B.R. Larson. 1981. Regrowth of Ascophyllum nodosum and

Fucus vesiculosus under various harvesting regimes in Maine, U.S.A. Bot. Mar.

24: 29-38

Lazo, L., and A.R.O. Chapman. 1996. Effects of harvesting on Ascophyllum nodosum (L.)

Le Jol. (Fucales, Phaeophyta): a demographic approach. J. appl. Phycol. 8: 87-103

MacEachreon, Tom. 1999. Compliance Monitoring in the New Brunswick Rockweed

Fishery (1996-1998). Stock Status Report for the April 28 and 29, 1999 Regional

Advisory meeting.

The Minch Project: Littoral Seaweed Resource Management. 1999. Environmental &

Resource Technology Ltd.

http://www.w-isles.gov.uk/w-isles/minch/coastal/seaweed-01.htm

Moss, Betty. 1970. Meristems and growth control in Ascophyllum nodosum (L.) Le Jol.

New Phytol. Vol. 69:253-260.

70

http://www.w-isles.gov.uk/w-isles/minch/coastal/seaweed-01.htm

Nebb, Harald, and Arne Jensen. 1966. Seaweed meal as a source of minerals and

vitamins in rations for dairy cows and bacon pigs. Proc. Int. Seaweed Symp.

5:387-393.

Parsons, Gerald Jay. 1986. Floating algal rafts and their associated fauna in

Passamaquoddy Bay, New Brunswick. M.S.c., Acadia University. Abstract only.

Rangeley, Robert W., and Donald L. Kramer. 1995a. Use of rocky intertidal habitats by

juvenile Pollock Pollachius virens. Mar. Ecol. Prog. Ser. 126: 9-17.

1995b. Tidal effects on habitat selection and aggregation by juvenile Pollock

Pollachius virens in the intertidal zone. Mar. Ecol. Prog. Ser. 126: 19-29.

Sharp, G. 1981. An assessment of Ascophyllum nodosum harvesting methods in

southeastern Nova Scotia. Canadian Technical Report of Fisheries and Aquatic

Sciences, 1012.

1986. Ascophyllum nodosum and its harvesting in Eastern Canada. In Case

Studies of Seven Commercial Seaweed Resources . Eds. M.S. Doty, J.F. Caddy

and B. Santelices. FAO Fish. Tech Pap. (281):311p.

Sharp, G., R. Ugarte, T. MacEachreon, R. Semple, and G. Black. 1999a. Structure of the

Ascophyllum nodosum (rockweed) Habitat and the Effects of Harvesting

Perturbation in Southern New Brunswick. RAP Working Paper 99/29.

Sharp, Glen, Robert Semple and Ian Barkhouse. 1999b. Habitat architecture and

invertebrates of Ascophyllum nodosum: a summary. Presentation at the Gulf of Maine Rockweed Conference, St. Andrews, New Brunswick, Dec. 5-7, 1999.

71

Smith, S. D., 2000. An Independent Study and Review of the New Brunswick Rockweed

Harvest. Phase 1.

Ugarte, R. 1999. An assessment of Ascophyllum nodosum Resources in Southern New

Brunswick 1995-1996.

Ugarte, R. and B. Moore. 1999. Population structure and dynamic of Ascophyllum

nodosum in Southern New Brunswick.

Vadas, R.L., and W. A. Wright. 1986. Recruitment, growth and management of

Ascophyllum nodosum. Actas II Congr. Algas Mar. Chilenas: 101-113.

For further reading see phase 1 study section 15 put together by Stephanie D. Smith 2000.

72

Rockweed2005

Documents

rockweed study

rockweed population

description of rockweed

study phase

nova scotia rockweed

length of rockweed clumps

world rockweed industry

untouched stands of