Passive acoustic monitoring of fishes in the mid-Atlantic: providing the where and when for managers Delaware State University, Department of Agriculture and Natural Resources, Dover, DE [email protected] Dewayne Fox
Jan 15, 2016
Passive acoustic monitoring of fishes in the mid-Atlantic:
providing the where and when for managers
Delaware State University, Department of Agriculture and Natural Resources, Dover, DE
Dewayne Fox
Outline
• Atlantic sturgeon– Phil Simpson
• Sandtiger shark– Johnny Moore
• Conclusions
Sturgeons• Fossil records back 85
MYBP• 25 species worldwide
with 9 species in North America
• Anadromous or restricted to freshwater
• Body with 5 rows of scutes
• Nearly all species are endangered or threatened
Sturgeon Harvesting
• Vulnerability due to life history traits
• “Black gold”– Ex-vessel prices >$50/lb– Retail >$200/ounce
• Delayed maturation and long life spans (>100 years)
• Limited prospects for natural recovery in many populations
Atlantic sturgeon(Acipenser oxyrinchus oxyrinchus)
• Anadromous• Range
– St. Lawrence River, Canada to St. Johns River, FL
• Long lived – Large (4.3m and 350 kg)– 60 years
• Late-maturing– Males 10-12 years– Females 13-20 years
• Spawning Requirements– Hard substrate with high flow
rates– Fresh water
Atlantic Sturgeon Migration
Spring
Atlantic Sturgeon Migration
Summer
?
?
?
?
Atlantic Sturgeon Migration
Fall
Atlantic Sturgeon Migration
Winter
100+ years of Atlantic Sturgeon Management in the Delaware
River• “The roe was considered
worthless except as bait to catch eels, and perch or to feed the hogs” • Cobb, J. N. 1900
• “Under the present conditions it is only a question of a few years until the day of the sturgeon fishery will have collapsed” • Tower, W. S. 1908
Atlantic sturgeon Fishery Management: Modern Challenges
• ASMFC issued Fishery Management Plan 1990
• Fishing moratorium (1998)
• Status review (1998)– Did not warrant protection
– Harvest moratorium issued
• Status review (Feb 2007)– 3 of 5 Distinct Population
Segments (DPSs) recommended for threatened status
Distinct Population Segments
(DPS)• Threatened
– Carolina– Chesapeake Bay– New York Bight
• Not listed– Gulf of Maine– South Atlantic
Status Review 2007
History of Delaware River Atlantic Sturgeon Fishery
• Leni Lenape Indians “celebrated the arrival of the sturgeon with an orgy of fishing”
• 1869 Penn’s Grove– “Albany beef”
• 1889 Caviar, NJ– 400 harvesters– 12-15 railroad cars
daily– Up to 5 railroad cars
of caviar daily
Caviar, NJ
Delaware River Atlantic Sturgeon Fishery
• Historic Abundance estimated at 180K Females in 1890
• Average weight– female 118 kg– male 29.5 kg
0
1
2
3
4
5
6
7
YearYear
Lan
din
gs
(mill
ion
lbs)
Lan
din
gs
(mill
ion
lbs)
Stock CollapseStock Collapse
Golden YearsGolden Years
Recruitment FailureRecruitment Failure
Secor and Waldman 1999
Delaware River• Largest freshwater
port complex in world• Over 3000 deep draft
vessels/year• 42 million gallons
crude oil moved daily
Juvenile Habitat Utilization
• Estuarine/marine residency– GROWTH
• May occupy non-natal estuaries during spring/summer
Objectives• Characterize habitat
use during period of estuarine residency– Substrate– Depth – Environmental
parameters
• Identify migratory patterns– Immigration/emigration
Methods: Collection/Telemetry
• Gill nets– Varying mesh sizes (15–
30.5 cm)– Anchored vs. drift
• Telemetry– Internal
transmitters– Previously
established surgical protocol
Telemetry Equipment
• Vemco ltd.– Sturgeon – 2 year tags– Battery life- 10 years– VR-2 passive receivers
• Data sharing– Delaware Estuary
• shortnose sturgeon
• striped bass
• horseshoe crab
• sandbar and sand tiger sharks
– Atlantic Cooperative Telemetry (ACT) Network
• 28 research groups ME-FL
VEMCO
VEMCO
VEMCO
Telemetry Array
• 2005 (n=38)
• 2006 (n=55)
• 2007 (n=56)
• 2008 (n=63)
Telemetry Equipment
Based on M. Moser design
Active Tracking• Focus on juvenile habitat
– Range based on C.A. Shirey (1997) telemetry study
• Methods– Weekly monitoring of
riverine section– Listen at 1 km intervals
2005-2007 Juvenile Sturgeon
Passive Relocations (n=279,167)
• 2005 (n = 15)– well defined concentration areas
• (Shirey 1997)
• 2006 (n = 12)– concentration zones less defined
• 2007 (n = 10*)– increased heterogeneity in habitat occupation
*based on returns, no new fish tagged
Atlantic sturgeon movement 2005-2007
2005
0
20
40
60
80
100
120
140
160
19-Mar 18-Apr 18-May 17-Jun 17-Jul 16-Aug 15-Sep 15-Oct 14-Nov
Date
river
kilo
met
er
0
5
10
15
20
25
30
35
Tem
pera
ture
(deg
rees
Cel
sius
)
2006
0
20
40
60
80
100
120
140
160
19-Mar 18-Apr 18-May 17-Jun 17-Jul 16-Aug 15-Sep 15-Oct 14-Nov
Date
rive
r ki
lom
eter
0
5
10
15
20
25
30
35
Tem
per
atu
re (d
egre
es C
elsi
us)
2007
0
20
40
60
80
100
120
140
160
19-Mar 18-Apr 18-May 17-Jun 17-Jul 16-Aug 15-Sep 15-Oct 14-Nov
Date
rive
r ki
lom
eter
0
5
10
15
20
25
30
35
Tem
per
atu
re (
deg
rees
Cel
siu
s)
2007 Juvenile Atlantic sturgeon
2007
0
20
40
60
80
100
120
140
160
19-Mar 18-Apr 18-May 17-Jun 17-Jul 16-Aug 15-Sep 15-Oct 14-Nov
Date
rive
r ki
lom
eter
0
5
10
15
20
25
30
35
Tem
per
atu
re (
deg
rees
Cel
siu
s)
• Representative data?
• Immigration and emigration patterns
• Movement driven by prey resources?– Polychaete or “mud”
worms (ECS 1993)• Johnson et al. 1997• Haley 1998
Polychaete bloom
Habitat Selection: DNREC Delaware Bay Benthic Mapping Program
Images courtesy of Bart Wilson
Habitat Utilization: Substrate
• Delaware state benthic mapping program dataset
• Independent sediment analysis– 90% correlation macro-
format classification
• Individual Chi-square test– Collectively, habitat
selection is occurring for gravel/hard-bottom substrate
• X2 (308.91) > test statistic (149.45), df = 100
0
20
40
60
80
100
Clayey Silt Silt, w ith Clay Sand/Silt, w ithClay
Sand Gravel Rock
Sediment Classification
Nu
mb
er o
f R
elo
cati
on
s
Expected
Observed
Habitat Utilization:
Depth• Data Source:
NOAA Bathymetric Maps
• Commonly relocated in/along navigation channel
• Anchorage areas
Habitat Utilization: Depth
0
10
20
30
40
50
60
70
80
0-4 4-8 8 -12 12-16 16-20 21-25
Depth (m)
Nu
mb
er o
f Rel
oca
tions
Expected
Observed• Deep water
habitat selection– Collectively,
selection for 8 – 16m depths
• X2 (238.4) > test statistic (149.5), df = 100
Conclusions for Delaware River Atlantic sturgeon
• Juvenile habitat utilization– Depth and substrate selection
• Deep water secondary channel/anchorage areas
• Coarse grain materials
– Migratory Patterns• March 19 immigration• November 24 emigration
– Migratory patterns indicate marine overwintering habitat
– Recent discovery (Feb 14, 2008) of juvenile mortality within estuary ( ≈river kilometer 80)
– Wide use of riverine habitat during estuarine residency
Conclusions• Deepwater habitat selection outside main traffic area
–Crown Landing LNG Proposal
–Delaware Deepening Project
• Critical habitat designation–Gravel/hard-bottom substrate, depth preferences, prey availability, physiochemical properties
•Migratory patterns indicate marine overwintering habitat
–March 19 return – Dec 17 exit
–Recent discovery (Feb 14, 2008) of juvenile mortality within estuary ( ≈river kilometer 80)
–Boat Strikes
Site fidelity and patterns of habitat use of sandtiger sharks (Carcharias
taurus) in Delaware Bay
Life History• Females
– Mature at 220-230 cm TL– 9-10 years of age
• Males– Mature at 190 cm TL– 6-7 years
• Maximum Size ≈ 4m
• Size at birth ≈ 1m
• Forage on fishes including other sharks/rays, horseshoe crabs, and mollusks
• Thought to be primarily nocturnal
Reproduction
• 2 year reproductive cycle– 9-12 month gestation
• Litter size of 2– embryophagy
• 1 female every other year assuming 1:1 sex ratio
• 0.5 female offspring per year
• Among lowest reproductive output for any known shark or ray
Management1993 - NMFS FMP large coastal
species
1997 - NMFS prohibited species category
1997 - petitioned for ESA listing
2007 Stock Assessment and Status Review (?)
Catch of Sandtiger Sharks Reported in US Commercial Fisheries 1981-2002
05000
100001500020000
250003000035000
4000045000
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
Year
Dre
esed
Wei
ght
(lb
s)
Sand Tiger Shark
Migration
MatingFebruary to May
Sand Tiger Shark
Migration
PuppingDecember to March
Pregnant females
do not migrate?
Sand Tiger Shark
Migration
Spring Migration
Salinit
ies to
o low
?
Pregnant females
do not migrate?
Age 1+
YOY??
Sand Tiger Shark
Migration
Age 1+
YOY??
Fall Migration
Methods
• Long line – 366 m length– Baited circle hooks (16/0)– 2 hour soak times
• Directed sampling and random NMFS Apex predator surveys
• All sand tigers were measured, sexed, fitted with an external tag, and had genetic samples collected
Tagging
• Implanted with long-life (800 days) standard acoustic transmitters (V16-6H)– 2006 n = 4– 2007 n = 15
• Implanted with long-life (800 days) depth sensing transmitters (V16-6H)– 2007 n = 10
Results
• Total of 29 sand tigers were implanted with acoustic transmitters– 2006 n = 4– 2007 n = 25
• 17 female • 12 male
2007 Results
• 2 / 4 sand tigers tagged in 2006 returned in 2007
• Both returned on June 17th
• All telemetered sand tiger sharks were detected
• Total detections = 72,241
Results
• Tagging initiated in June and completed in July
• > ½ of all telemetered Sand tiger sharks remained in Delaware Bay into October
Proportion of Sand Tiger Sharks Detected
0%
20%
40%
60%
80%
100%
June July August September October
Relative Detections by Receiver for 2007
• Importance of Delaware’s side of the Bay
• Relative absence along main channel area
• Cape May early in year
Relative Proportion of Detections by Sex
• Males tended to occupy lower salinity upper bay and nearshore areas
• Females detected more commonly in lower/deeper portions of the bay
Habitat Utilization: Depth
Mean Detection Depth (m) for 2007
7.00
7.25
7.50
7.75
8.00
June July August September October
Mean Detection Depth (m) by sex for 2007
5.0
6.0
7.0
8.0
9.0
10.0
June July August September October
Mean Depth (F)
Mean Depth (M)
Dep
th (
m)
05
101520253035
1786
6 7 8 9 10 6 7 8 9 10
Female Male
Month within Sex
Dep
th (
m)
05
101520253035
1786
6 7 8 9 10 6 7 8 9 10
Female Male
Month within Sex
Conclusions• Delaware Bay serves as
an important nursery habitat as well as summer foraging area for Sand tigers
• Majority of STS exhibit high fidelity for Delaware Bay (>60%)
• Importance of Delaware shoreline and Cape May regions– Anchorage area
• Sex-based distribution by area and depth
Acknowledgements• Students• Staff- Lori Brown• Brad Wetherbee-URI• NOAA EPP and
Anadromous Fish Conservation Act Funding
• United States Coast Guard– LCDR Retired Thomas
Flynn, Norfolk ATON Office
– USCG Cutter William Tate
• Bart Wilson, DNREC
Questions?
• www.hpl.umces.edu/ facilities/sturgeon.jpg