8/10/2019 Fish Farming Technology supplement 1406
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FISH FARMINGTECHNOLOGY
SUPPLEMENT
The MAG seal
deterrent system
Temperature stress
Water temperature and stress control
SUPPLEMENT
The MAG seal deterrent is the most effectiveand cetacean-friendly device on the market
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SoundtechnologyThe MAG seal deterrent is the most effective
and cetacean-friendly device on the market
For the last 20 or so years the
Airmar DBII+ has been considered
the best Seal Deterrent on the
market. And whilst this system is
as good as ever, Mohn Aqua felt that as the
Control System uses 1980s technology, it
could do with modernising.
So, with the help, advice and blessing of
Airmar, Mohn Aqua developed a new, state-of-the-art Control Box the MAG Seal
Deterrent which, amongst other things,
increased the system from a four projector
system to one that offered the choice of two,
four or six projectors. As such, it can be set
up as a standard four-Projector System and, ifa site is experiencing problems, another two
Projectors can be added.
'Another important advantage of the new
system', says Mal Scott, General Manager of
Mohn Aqua, 'is that the Pulses can be varied, in
power, duration and firing pattern. Plus, it is 50
per cent more efficient than the DBII+, which
means half the batteries need to be used, or
existing batteries last twice as long during
power outages.'
The MAG Seal deterrent was also devel-
oped after discussions with both the Seal
Mammal Research Unit and the Salmon
Aquaculture and Seals Working Group, where
two concerns with current ADDs were iden-tified. The first was that operators could not
immediately tell that a system had a fault until,
for example, there was a sudden increase in
morts. Secondly, there is a growing feeling
that systems need to become more Cetacean
Friendly.As such, the MAG Seal Deterrent has
Fault Indicators for each Projector. After a
'soft start' Switch designed to not instantly
frighten Cetacean, the super bright LEDs turn
from Amber to Green, with the Projector that
is firing at the time flashing Green. This lets the
operators know from a huge distance away
that all is good.
Any faults on a Projector or Cable are
instantly recognised by an internal Processor,
and the channel is automatically shut down,
preventing damage to the Control Circuits.
The LED for that Channel instantly turns red
and the operators know which channel and
which projector has a problem. This is par-
ticularly useful for audits, which are now are
carried out in monitoring Seal problems. The
next Generation of projectors, which will be
available as soon as Airmar have finished trials
and star t manufacture, have an inbuilt Sensor
that will give even more fault information to
the new control box.
Cetacean-friendlyMohn Aqua also believe that the MAG
Seal Deterrent is the most Cetacean-
friendly system available. It can be put into
a 'Standby' mode, where the output can be
toned down to very low levels when there
is not a current threat to the site. This way,
Cetacean, always know the system is there,
keep a distance away, but are not frightened
by it. When a threat does occur, the system
can be switched back to normal operation
through the 'soft start' sequence. This is far
better than a 'detection' system that will lay
dormant, almost asking Cetacean to come
close, then fire unexpectedly, causing fear and
panic.
This system is also fully compatible with cus-tomers' existing DBII+ Projectors , meaning
that to upgrade sites only have to replace the
Control Box and not the full installation.
The MAG Seal Deterrent system has been
installed at a number of Scottish Seafarms
002 | INTERNATIONAL AQUAFEED | Fish farming Technology
FISH FARMING TECHNOLOGY
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(SSF), Marine Harvest and Scottish
Salmon Company sites, as well as
three large Salmones Maga llanes
sites in Chile, where they have
proved to be extremely effective. For
example, as Ewan Gibb, site manager
at SSF Summer Isles, explains: 'Early
on in the year we had a severe seal
issue at one cage in particular. Once
the new system was installed, over-night the seal problem stopped at
that cage; and progressed to another
cage.
'What I like about them is that they
can be programmed on site, they
don't need to be taken away, and
you can also vary frequencies, pulse
rates, the gaps between the pulses
everything is adjustable on it. It's
really doing the job well.'
This is echoed by Colin MacDonald,
site manager at SSF Scallastle: 'It's a
very good system and the display
panel is very clear and easy to read',
he explains. 'Since we've had it
installed we've had no problems with
seals; we have no complaints with it
at all.'
Mohn Aqua is also beginning an
agreement with Scottish Seafarms
in Shetland, which will see the
company carrying out an audit of all
SSF Shetlands existing Airmar/Mohn
Aqua Seal Deterrent equipment. This
will lead to SSF Shetland receiving theoptimum efficiency from its existing
equipment and recommendations for
modification and upgrades to ensure
that they continue to have the very
best possible protection in the future.
Fish farming Technology | INTERNATIONAL AQUAFEED| 003
FISH FARMING TECHNOLOGY
50% more efcient than the Airmar DB11
Varies pattern, length and breaks of pulses preventing seal attacks
Works perfectly with existing projectors, just upgrade the control box
Fault protection, upgraded cover, cetacean friendly
Replace your Metal halide lights with ourRevolutionary LED light system
Reduces 75% of electricity use
Weighs only one kilo, can be installed by one person
We think this is thebest Seal Deterrent
on the market(so does Airmar, which is why they tested and approved it)
Scotland: +44 (0) 1309 678270Norway: +47 53 500 [email protected]
www.mohnaqua.com
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M
ost aquatic animals are
poikilothermic whose
metabolism and growth
are closely related to the
environmental temperature. All farmed fishand shrimps have their optimum range of
temperatures for growth. At temperatures
outside this range, metabolism and growth
are severely affected and may eventually
cause death if the water temperature drifted
too far away from the optimum range. This
article provides a review on the nutritional
physiology of aquatic animals affected by
temperature fluctuations with some recently
published data.
In recent years, the erratic changes inglobal temperatures have caused huge losses
to aquaculture in China and elsewhere.
Guangxi Aquatic animal husbandry and vet-
erinary Association reported that in 2011
alone, fishery economic loss affected by tem-
perature was more than 100 million Yuan.
China-Fishery net reported that in 2013
Jiangxi aquaculture economic loss affected by
low temperature was more than 80 million
yuan; Anhui fishery economic loss affected
by high temperature was as high as 100
million yuan.
The influence of watertemperature on fishbehavior and physiology
Water temperature and fish feedingThe change of environmental tempera-
ture directly affects the fish feeding and
growth. When temperature increases within
the range of optimum temperatures, cor-
responding metabolism, food intake, growth
also increases. Both feed intake and feed effi-
ciency will decrease at temperatures higheror lower than the optimum temperature.
It is important for aquaculture industry to
understand the growing temperature to
optimize feeding management and minimise
the feed cost.
The influence of watertemperature on fish immunity
The change in environmental temperature
also affects fish immune and metabolism. Qin
Chuanjie reported that water temperaturemainly affects the antibody secretion and the
activity of immune active cells and quantity,
lysozyme activity and complement activation
pathways and activity. When the environmen-
tal temperature is higher than physiological
adaptation range, specific and nonspecific
immune activity of fish are subdued. However,
within the optimum temperature range, if one
of the immune system (one of the specific or
non-specific immunity) is weakened by a small
temperature change, some other immune
systems are usually improved.
Water temperature andenergy metabolism
Study on fish energy metabolism analyses
the quantitative relationship between energy
balance components and the effect of various
ecological factors. Cui and Wootton first put
forward the idea of restricted feeding during
abnormal temperature to keep the balance
of each energy component in sunfish. Then
Xie & Sun and Cui et al. reached a similar
conclusion in a study with southern catfish
and grass carp. But Sun Yao found that the
temperature significantly affects energy bal-
ance model in black bream, red porgy and
black Jun. Within the appropriate temperature
range, feed intake, growth, metabolism and
excretion rate showed a trend of slow growth
with increasing temperature. That is to say,
under the condition of ad libitum feeding,
fish energy distribution pattern is still affected
by temperature. Because of differences in
adaptive mechanisms among various groups
of fish species it is important to establish the
energy budget for individual species to be ableto determine the energy required for basal
metabolism and for other metabolic activities
at various temperatures.
Temperature is an important factor of
affecting basal or resting metabolism, which
is mainly the amount of energy required to
maintain homeostasis when inactive. Within
the appropriate temperature range, respi-
ration and oxygen consumption increases
with the increase of environmental tempera-ture [12].In this case, with the temperature
increasing, metabolism, enzyme activity, basic
metabolism of fish will increase causing higher
energy requirement for basal metabolism. On
the other hand, as the water temperature
exceeds the optimum range, oxygen con-
sumption rate will drop down decreases with
the rise of temperature. It happens because
of decreasing metabolic requirement because
of reduced enzyme activity, degeneration or
Planning water temperature and stress control through aquatic feedsby Ruijian Sun, Haifeng Mi, Lu Zhang, Wugang Wang,Yuanhong,wen, Chuny Xue Technology center oftongwei Co., LTD Chengdu, 610041
004 | INTERNATIONAL AQUAFEED | Fish farming Technology
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means would be highly beneficial to the farm-
ing industry. Hence, nutritional regulations
with appropriate dietary supplements such as
energy-yielding or anti-stress substances can
improve fish immunity and anti-stress activity,
and may well result in reduction of the loss of
productivity due to heat stress.
Nutrition regulation under highwater temperature condition
Many published studies have discussed fish
physiological responses under high tempera-
ture but few researches elucidated nutritional
regulation to reduce the effect. Fish shows
lower growth and higher protein turnover rate
during heat stress. An increase in dietary pro-
tein to energy ratio might meet the increased
need of proteins. Glencross et al. (2010)
reported that increased dietary protein to
energy ratio of barramundi (Lates calcarifer)
provided significant benefits in terms of reduc-
ing the impact of growth retardation under
heat stress. However, it was not observedin Atlantic salmon that can be related to the
narrow range of dietary protein to energy
ratio. In Nile tilapia (Oreochromis niloticus),
Caroline et al. (2012) reported decreased
synthetic rate and concentration of blood
cell, reduced the activity to transport oxygen,
under heat stress affecting fish health. The
authors showed that dietary supplementation
of vitamin B6 could enhance blood cell syn-
thesis resulting in better growth performance.
Nutritional regulation atlow temperature stressThe membrane fluidity is decided by the
fatty acid composition in membrane lipid and
usually decreased during low temperature.
Earlier studies showed that the unsaturated
fatty acid concentration in cell membrane
is positively correlated to the cold stress
resistance capacity in fish-
-. Thus, increasing the
dietary poly-unsaturated
fatty acids, especially the
n-3 unsaturated fatty
acids, can improve the
cold stress resistance
capacity in fish.
An increase in dietary
tryptophan, methio-
nine and tyrosine can
also improve cold-stress
resistance during winter.
Tyrosine is the precursor
of catecholamine, which
is the precursor of nor-
epinephrine (NA) and
adrenaline (Adr). Both NAand Adr can regulate the
metabolic balance helping
fish to adapt to the stress.
The supplementation of
tyrosine increases the cold
resistance capacity of fish by improving the
biosynthesis of catecholamine.
On the other hand, tryptophan, a pre-
cursor of 5-hydroxytryptamine (5-HT) that
regulates secretion of some hormones, can
improve fishs cold stress resistance capacity
by regulating feed intake. Methionine, as the
methyl donor, is involved in the methylation
process of hormones, nucleic acids and neu-
rotransmitters. Cheng et al. [32] showed that
the lack of methionine may lower fishs cold
resistance capacity.
The supplementation of dietary vitamin
E and vitamin C under cold stress has also
shown to eradicate the peroxide and the over
all concentration of free radicals, which can
improve immunity and maintain physiological
homeostasis. Pitaksong et al. reported that the
supplementation of vitamin E and vitamin C in
diet improves growth performance of catfish
under cold stress and enhance its physiological
and immunity conditions.
The supplementation of dietary mineralsis also good for fish to resist the cold stress.
Minerals such as Zn and Fe in combination
with the antioxidants, can erase the peroxide
in fish. The supplementation of dietary Zn
can increase cold resistance by keeping the
mitochondrial membrane balance in fish under
cold-stress [34]. Where as, supplementation
of Fe may improve respiratory enzyme activity
and prevent anemia. However, higher supple-
mentation of minerals in fish feed than the safe
amount may become toxic and do more harm
than good.
Recently, researches indicated the capacity
of some Chinese herbs to improve immune
response in fish. The natural components
of Chinese herbs, such as flavonoids and
curcumin, can serve as antioxidants enhanc-
ing the antioxidative activities in fish. Thus,
the supplementation of Chinese herbal can
increase the immune function and cold resist-
ance capacity of fish.
Moreover, high dietary protein or energy
may help fish to resist the cold stress. Kevin
reported showed higher growth performance
and feed efficiency under cold stress in Asian
sea bass (Lates calcarifer) fed high energy
diets compared to those fed the low energy
diets. On the other hand, Qiang et al found
that tilapia fed with high protein feed showed
high glucose, cholesterol, total protein and
triglyceride levels in their serum, which can
supply energy during cold stress.
Commercial Tilapia feed adjustmentprogram in Guangdong
Tilapia is a popular food fish cultured
mainly in Guangdong, Guangxi and Hainan.
They are omnivores and well adapted to
hypoxia, while they are intolerant to low or
high temperature. The optimal temperature
for tilapia growth varied between 22 and 32
. Their feed intake halts at temperaturebelow 15 , and usually dies at temperature
below 10. Based on the research findings,
we made a feed adjustment program for
tilapia according to annual water tempera-
ture profile in Guangdong. The performance
of tilapia fed following the program seems
encouraging (Table 1).
ConclusionClimatic condition is complex and tem-
perature change is acute in china, inducing
huge losses to the aquaculture industry.In order to get better value for money in
aquaculture, enhanced resistance to the
stress from temperature fluctuation beyond
the optimum range becomes very impor-
tant. Therefore, in addit ion to improving
the qual ity of fish fry, the strengthen-
ing of research to enhance the resistance
to temperature stress
regulated by nutritional
means is necessary.
We reviewed the
effects of temperature on
fish, nutritional regulation
of temperature stress and
developed a successful
feed-management solu-
tion for tilapia under such
stresses. We hope the
study can provide refer-
ence for improving the
accuracy of dietary nutri-
ents, developing cost-
effective functional feed,
thereby reducing damage
to the farming industrycaused by temperature
stress.
ReferencesAvailable on request
Table 1: Tilapia feed adjustment program in Guangdong
MonthsTemperatureconditions
Affects Feed adjustment plans
Dec - Feb
Lowtemperature,some days
below 15
Feed intake islow and growth
is slow
Increase the proportion of protein tomaintain the growth and health; keepthe lipid level to prevent shedding
weight and resistant to low temperaturestress; energy feed was not effectivein this period, phosphorus can be setlower.
Mar - May
Watertemperature
increased andcan reach 25
Increased feedintake &fishrecovered
Keep the protein stable, increaselipid level and add vitamin andimmunopotentiator
Jun - SepWater
temperaturereached 30
Much high feedintake, active
metabolism andrapid growth
Increase the proportion of proteinand lipid, supply enough vitamin and
mineral and ensure the health of liverand intestine
Oct - Nov
Watertemperaturedecreased to
25
Feed intakewas large
Increase the proportion of proteinand lipid, reduce additives for health,add additives for lipid absorption likecholine.
006 | INTERNATIONAL AQUAFEED | Fish farming Technology
FISH FARMING TECHNOLOGY
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FISH FARMING TECHNOLOGY
Extruder OEE for the Production of Fish FeedExtruder OEE for the Production of Fish Feed
AMANDUS KAHL GmbH & Co. KG, Dieselstrasse 5-9, D-21465 Reinbek / Hamburg,
Phone: +49 40 727 71 0, Fax: +49 40 727 71 100, [email protected] www.akahl.de
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EdicinEspaola
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Animal co-product
hydrolysates: a source of key molecules in aquaculture
feeds
Prevalence of mycotoxinsin
aquafeed ingredients: an update
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FIS H FAR M ING TE CHNOLOGY
New functional
fish feedsto reduce
cardiovascular disease
Pellet distribution modelling: a tool for improvedfeed delivery in sea ca ges
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The potential of
microalgae meals in compound feedsfor aquaculture
Understanding ammonia
in aquaculture ponds
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EXPERT TOPIC Salmon
AquaNor event review
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Maintaining ingredient
quality in extruded feeds
Fine particle filtration in
aquaculture
Effect of probiotic,
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EXPERT TOPIC channel c atfish
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They are what they eatEnhancing thenutritional value of livefeeds
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Controlling mycotoxinswith
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Ultraviolet
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farmsand hatcheries
Niacin one of the keyB v itaminsfor sustaining
healthy fish growth andproduction
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Transformingaquaculture
production using
oxygenation systems
Nutritional benefitsof
processed animal proteins in European aquafeeds
Towardsaquafeeds with
increased food security
Bioenergetics application in aquaculturenutrition
VOLUME 16 ISSUE 2 2013 - MARCH | APRIL
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Chicken viscerafor fish
feed formulation
Profitable aquafeed
moisturecontrol
Theshrimp feed industryin China an overview
Spray-dried plasma from porcine blood in dietsfor Atlantic
salmon parrs
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