Salmon Farming in Salmon Farming in Scotland: the key Scotland: the key

environmental issuesenvironmental issues

Kenny BlackKenny BlackScottish Association for Marine Scottish Association for Marine

ScienceScience

ObanOban

Dunstaffnage Marine Laboratory

Aims to:

•develop, promote and support research in marine science

•facilitate communication through conferences and seminars

•support the teaching of marine science throughout Scotland

•become the authoritative voice of marine science in Scotland

•www.sams.ac.uk

Scottish Association for Marine Science

Established 1884

Political backgroundPolitical background

• PetitionPetition• Parliamentary Inquiry Parliamentary Inquiry • Review and Synthesis for Scottish Review and Synthesis for Scottish

Exec and Parliament, SAMS/Napier Exec and Parliament, SAMS/Napier Univ.Univ.

• http://www.scotland.gov.uk/cru/kd01/green/reia-00.asp

• Ministerial Working Group on Ministerial Working Group on Aquaculture StrategyAquaculture Strategy

SummarySummary

• The contribution of salmon farming The contribution of salmon farming to Scotlandto Scotland

• The key environmental effects of The key environmental effects of salmon farming, risks and salmon farming, risks and strategiesstrategies

Global Aquaculture TrendsGlobal Aquaculture Trends

• 19,244,000 tonnes all fish species 19,244,000 tonnes all fish species 20002000

• 46,153,000 tonnes predicted for 46,153,000 tonnes predicted for 20102010

• 876,000 tonnes salmon in 2000876,000 tonnes salmon in 2000• 1,569,000 tonnes predicted for 20101,569,000 tonnes predicted for 2010

Atlantic Salmon Production in Scotland, tonnes

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

180,000

19

84

19

85

19

86

19

87

19

88

19

89

19

90

19

91

19

92

19

93

19

94

19

95

19

96

19

97

19

98

19

99

20

00

20

01

60% production from 11% farms > 1000 t

Economic value to Economic value to ScotlandScotland

• The Scottish salmon farming industry The Scottish salmon farming industry employs 6500 people, 70% of which live in employs 6500 people, 70% of which live in rural areas contributing about £2M per rural areas contributing about £2M per week to remote economies in wages alone. week to remote economies in wages alone.

• The farm-gate value is around £300M p.a. The farm-gate value is around £300M p.a. – greater than Highland beef and lamb – greater than Highland beef and lamb combined. combined.

• Of a total Scottish food export of £400M, Of a total Scottish food export of £400M, salmon contributes 40%. salmon contributes 40%.

Salmon FarmingSalmon Farming

• Smolts put to sea in March at 60g Smolts put to sea in March at 60g and continuously harvested from and continuously harvested from December (>1kg) for one year (up to December (>1kg) for one year (up to 7 kg). 7 kg).

• Salmon have very high growth rates.Salmon have very high growth rates.• Salmon feed high in protein and oil.Salmon feed high in protein and oil.• A 1000 t biomass farm produces A 1000 t biomass farm produces

about 1750 t of fish per cycle.about 1750 t of fish per cycle.

Salmon Salmon FarmingFarming

2.8 kg for protein

+ 0.8 - 2.3 kg extra for oil

Fish Feed40% Protein30% oil9% water1200g: N 96gP 18gC 660g

Harvest Fish

1 kg

N 26gP 3.2gC 139gMortalitie

s and escapes

N 1.9gP 0.4gC 13g

Particulate wastes

N 22gP 9.5gC 185g

Soluble wastesN 46gP 4.9gC 323g

Budget for the flow of nutrients from oceanic wild caught fish to the coastal environment for a harvest of 1 kg of farmed salmon assuming no substitution with vegetable protein or oil and a ratio of fish feed to product of 1.2:1

Wild fish17% protein, 7-10% oil, 75% water

Waste food and faeces settle on the sea Waste food and faeces settle on the sea bed: distribution depends on current bed: distribution depends on current

regime and stratificationregime and stratification0 C u rre n t V e lo c ity

S ou rce

C oa rse M ed iu m

F in e

Effects on Sea bedEffects on Sea bed

Effects on sea bedEffects on sea bed

• Effects dependent on size of farm, quality of Effects dependent on size of farm, quality of management and hydrographic conditionsmanagement and hydrographic conditions

• All severe effects are constrained to the All severe effects are constrained to the area near the cagesarea near the cages

• Effects generally undetectable outwith Effects generally undetectable outwith 100m100m

• Farm size is determined by effects on sea Farm size is determined by effects on sea bed to keep these within ecological quality bed to keep these within ecological quality standardsstandards

• Pollution of the sea bed is Pollution of the sea bed is notnot a major a major constraint on expansion of farming.constraint on expansion of farming.

Effects on Water ColumnEffects on Water Column

• Three main concerns:Three main concerns:– nutrients from fin-fish farms have led to nutrients from fin-fish farms have led to

an increased occurrence of algal blooms; an increased occurrence of algal blooms; – nutrients from fin-fish farms have nutrients from fin-fish farms have

disturbed the natural ratios of nutrient disturbed the natural ratios of nutrient elements so favouring the occurrence of elements so favouring the occurrence of toxic species toxic species

– nutrients from fin-fish farms have made nutrients from fin-fish farms have made potentially toxic algae more poisonous. potentially toxic algae more poisonous.

PseudonitzschiaPseudonitzschia sp. sp.DiatomDiatom

Amnesiac Shellfish Amnesiac Shellfish PoisoningPoisoning

Domoic AcidDomoic Acid

Wide ranging scallop Wide ranging scallop closuresclosures

1. Increased blooms1. Increased blooms• Lack of long term data preclude direct Lack of long term data preclude direct

comparison with nutrient and comparison with nutrient and phytoplankton levels from pre-fish farm phytoplankton levels from pre-fish farm times. times.

• Modelling studies show that only a few sea Modelling studies show that only a few sea loch sites are strongly enriched: loch sites are strongly enriched: enrichments are generally low. enrichments are generally low.

• In addition, algal production attributable to In addition, algal production attributable to fish farm nutrients in Scottish coastal areas fish farm nutrients in Scottish coastal areas is small relative to that generated by is small relative to that generated by marine and terrestrial inputs. marine and terrestrial inputs.

2. Altered nutrient ratios favour toxic algae2. Altered nutrient ratios favour toxic algae

• Despite many lab studies, we are still a long Despite many lab studies, we are still a long way from understanding what controls the way from understanding what controls the balance of organisms within the plankton.balance of organisms within the plankton.

• For those algae associated with eutrophication For those algae associated with eutrophication ((Gymnodinium mikimtoi, Phaeocystis pouchetiiGymnodinium mikimtoi, Phaeocystis pouchetii and toxic flagellates) blooms do seem to be and toxic flagellates) blooms do seem to be stimulated by nutrient enrichment and stimulated by nutrient enrichment and increases in the ratio of N and P to Si. increases in the ratio of N and P to Si.

• That the abundances of the toxic species of That the abundances of the toxic species of Alexandrium, DinophysisAlexandrium, Dinophysis and and Pseudo–nitzschiaPseudo–nitzschia are related to changes in nutrient ratio in the are related to changes in nutrient ratio in the field remains speculative. field remains speculative.

3. Altered ratios increase toxicity of toxic 3. Altered ratios increase toxicity of toxic algaealgae

• The effect of fish farm waste on nutrient The effect of fish farm waste on nutrient element ratios in most Scottish cases can element ratios in most Scottish cases can be shown to be small. be shown to be small.

• Farm waste has a ratio of nitrogen to Farm waste has a ratio of nitrogen to phosphorus which is close to natural ratios.phosphorus which is close to natural ratios.

• Because of the absence of silicate in fish Because of the absence of silicate in fish foods there may be a danger of exceeding foods there may be a danger of exceeding the “safe” N:Si limit of 2.5 locally at heavily the “safe” N:Si limit of 2.5 locally at heavily enriched sites in summer when background enriched sites in summer when background nutrient levels are low and silicate has been nutrient levels are low and silicate has been drawn down by the Spring Bloom. drawn down by the Spring Bloom.

• However, modelling studies suggest However, modelling studies suggest that broad area effects should be small. that broad area effects should be small. Similarly there is no convincing Similarly there is no convincing evidence to suggest that changes in evidence to suggest that changes in nutrients as a result of fish farm inputs nutrients as a result of fish farm inputs ratios is likely to stress potentially toxic ratios is likely to stress potentially toxic species to cause them to increase their species to cause them to increase their toxicity. toxicity.

Water Column ConclusionsWater Column Conclusions

• Except perhaps in a few enclosed Except perhaps in a few enclosed waters, enrichment by fish farm waters, enrichment by fish farm nutrients is too little, relative to natural nutrients is too little, relative to natural levels, to have the alleged effects. levels, to have the alleged effects.

• BUT we cannot often support this BUT we cannot often support this conclusion with data from series of conclusion with data from series of measurements made at key sites measurements made at key sites over the several decades that span over the several decades that span the development of the industry.the development of the industry.

Aside: Shellfish cultureAside: Shellfish culture

• The cultivation of non-finfish species The cultivation of non-finfish species has few and only local negative has few and only local negative environmental impacts. As this type environmental impacts. As this type of culture extracts nutrients from the of culture extracts nutrients from the marine system, it is likely that the marine system, it is likely that the cultivation of non-fish species can, cultivation of non-fish species can, to some extent, help reduce nutrient to some extent, help reduce nutrient inputs from other activities including inputs from other activities including fish culture.fish culture.

Medicines and chemicalsMedicines and chemicals

• Antiparasitics (sea lice)Antiparasitics (sea lice)• AntibioticsAntibiotics• Metals (Antifoulants and feed)Metals (Antifoulants and feed)• DisinfectantsDisinfectants

Sea liceSea lice

• Sea lice are mobile ectoparasitic Sea lice are mobile ectoparasitic copepods, which live on the gills and copepods, which live on the gills and other body surfaces of fish. They other body surfaces of fish. They feed on mucus, skin and blood, feed on mucus, skin and blood, causing open wounds that expose causing open wounds that expose fish to osmotic and respiratory stress fish to osmotic and respiratory stress as well as providing a route for as well as providing a route for secondary infections by bacteria or secondary infections by bacteria or viruses. viruses.

• In the sea-cage rearing of salmon, In the sea-cage rearing of salmon, two sea lice species can cause two sea lice species can cause severe infestations, heavy severe infestations, heavy mortality and reduced mortality and reduced marketability. marketability.

• Lepeophtheirus salmonisLepeophtheirus salmonis is specific is specific to salmonids and to salmonids and Caligus elongatusCaligus elongatus is found on over 70 fish species. is found on over 70 fish species.

Adult male L. salmonis

Nauplius stage L. salmonis

Female C. elongatus

Sea lice life cycleSea lice life cycle

• The generation time of The generation time of L. salmonisL. salmonis from egg to ovigerous adult is 6 to from egg to ovigerous adult is 6 to 8 weeks at 108 weeks at 10ooC. Shorter at higher C. Shorter at higher temps and depends of species of temps and depends of species of salmon host.salmon host.

• C. elongatusC. elongatus has no preadult stage. has no preadult stage. Generation time is about 6 weeks at Generation time is about 6 weeks at 1010ooC.C.

•Sea lice infestations present a Sea lice infestations present a majormajor commercial and ecological problem.commercial and ecological problem.

•But we do not typically see fish like this But we do not typically see fish like this anymore as medicines are much improved.anymore as medicines are much improved.

Lice treatmentsLice treatments

• BathBath– Hydrogen peroxideHydrogen peroxide– CypermethrinCypermethrin– AzamethiphosAzamethiphos

• In-feedIn-feed- IvermectinIvermectin- Emamectin benzoateEmamectin benzoate- TeflubenzuronTeflubenzuron

• Cost – all medicines are Cost – all medicines are veryvery expensive expensive

Lice treatmentsLice treatments

• In-feed treatments should represent In-feed treatments should represent lower risk to the ecosystem as they lower risk to the ecosystem as they are used systemically, hence in are used systemically, hence in lower doses than the topically lower doses than the topically administered bath treatments, most administered bath treatments, most of which will be released directly and of which will be released directly and immediately to the environment immediately to the environment after treatmentafter treatment

RisksRisks• Hydrogen peroxideHydrogen peroxide – low environmental – low environmental

risk but not a good product, little used!risk but not a good product, little used!• AzamethiphosAzamethiphos – relatively low risk to the – relatively low risk to the

environment - concentrations quickly fall environment - concentrations quickly fall below EQSbelow EQS

• CypermethrinCypermethrin – generally low risk except – generally low risk except during multiple simultaneous treatmentsduring multiple simultaneous treatments

• EmamectinEmamectin – generally low risk – generally low risk• TeflubenzuronTeflubenzuron – relatively persistent – – relatively persistent –

moderate riskmoderate risk

BUTBUT

• All of these products are All of these products are highly highly toxic to crustaceanstoxic to crustaceans and the and the stated risks are only for authorised stated risks are only for authorised product formulations administered product formulations administered according to best practice.according to best practice.

AntibioticsAntibiotics

• Oxytetracycline, oxolinic acid, Oxytetracycline, oxolinic acid, trimethoprim, sulphadiazine and trimethoprim, sulphadiazine and amoxycillinamoxycillin

• Aquaculture is one of the Aquaculture is one of the leastleast medicated livestock industries: medicated livestock industries: antibiotics are not used antibiotics are not used prophylactically prophylactically

Concerns relating specifically to antibiotic Concerns relating specifically to antibiotic usage by the aquaculture industry are:usage by the aquaculture industry are:

• Development of drug resistance in fish pathogensDevelopment of drug resistance in fish pathogens• Spread of drug resistant plasmids to human Spread of drug resistant plasmids to human

pathogenspathogens• Transfer of resistant pathogens from fish farming Transfer of resistant pathogens from fish farming

to humansto humans• Presence of antibiotics in wild fishPresence of antibiotics in wild fish• Impact of antibiotics in sediments on: rates of Impact of antibiotics in sediments on: rates of

microbial processes; composition of bacterial microbial processes; composition of bacterial populations; relative size of resistant sub-populations; relative size of resistant sub-populations. populations.

RisksRisks

• We do We do notnot know the whole story know the whole story• Antibiotic usage has reduced Antibiotic usage has reduced

considerably over the past decade considerably over the past decade owing to the advent of effective owing to the advent of effective vaccines, especially for Furunculosisvaccines, especially for Furunculosis

• Sensibly used, antibiotics are Sensibly used, antibiotics are probably not a major risk to the probably not a major risk to the environmentenvironment

Metals from feedsMetals from feeds

• Concentrations in feeds range from 3.5 to Concentrations in feeds range from 3.5 to 25 mg Cu kg25 mg Cu kg-1-1 and 68 to 240 mg Zn kg and 68 to 240 mg Zn kg-1-1..

• The estimated dietary requirements of The estimated dietary requirements of Atlantic salmon for these elements are 5 Atlantic salmon for these elements are 5 to 10 mg Cu kgto 10 mg Cu kg-1-1, and 37 to 67 mg Zn kg, and 37 to 67 mg Zn kg--

11. Therefore, it would appear that the . Therefore, it would appear that the metal concentrations in some feeds are metal concentrations in some feeds are unnecessarily high as they exceed unnecessarily high as they exceed salmon dietary requirements.salmon dietary requirements.

Metals in antifoulantsMetals in antifoulants

• Formerly tributyl tin was used, very toxic Formerly tributyl tin was used, very toxic to invertebrates, now banned.to invertebrates, now banned.

• Most antifoulants are now copper based. Most antifoulants are now copper based. • Copper can accumulate in very high Copper can accumulate in very high

concentrations in sediments below cagesconcentrations in sediments below cages• Copper is probably released into the Copper is probably released into the

water-column but we do not yet have a water-column but we do not yet have a budgetbudget

• Ecological effects not well understoodEcological effects not well understood

Copper

Dec 2000

mg/ kg Probably Adverse

mg/ kg Potentially Problematic

mg/ kg Possibly Adverse

mg/ kg Background 1 6

3 5

1 0 8

2 7 0

SEPA Sediment Quality

Criteria for Copper -5

.53

0

-5.5

29

-5.5

28

-5.5

27

-5.5

26

-5.5

25

-5.5

24

Longitude (decim al degrees)

56.160

56.161

56.162

56.163

56.164L

ati

tud

e (

de

cim

al

de

gre

es

)

N

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

D istance from farm (m ) in the residual current d irection

-9.5

-8.5

-7.5

-6.5

-5.5

-4.5

-3.5

-2.5

-1.5

-0.5

Dep

th (

cm)

Depth Profile Copper

1 6

3 5

1 0 8

2 7 0 mg/kg Probably Adverse Action level inside AZE

mg/kg Possibly Adverse Action level outside AZE

mg/ kg Background

mg/kg Potential Problem Action level inside AZE

SEPA Sedim ent QualityCriteria for Copper

SEPA AZE (Allowable Zone of Effects) 25 m. Area in which some damage to environment is allowed: a mixing zone approach.

Actual AZE Limits

Disease and parasite Disease and parasite transfertransfer

• Gyrodactylus salarisGyrodactylus salaris• Infectious salmonid anaemia (ISA)Infectious salmonid anaemia (ISA)• Infectious Pancreatic Necrosis (IPN)Infectious Pancreatic Necrosis (IPN)• Sea liceSea lice

Gyrodactylus salarisGyrodactylus salaris

• Parasite transferred from resistant Parasite transferred from resistant Baltic salmon populations to Baltic salmon populations to Norwegian populations lacking Norwegian populations lacking resistance as a result of movements resistance as a result of movements of farmed fish in the mid-1970s. of farmed fish in the mid-1970s. ExtinctionExtinction of many wild populations. of many wild populations.

• Aquaculture Aquaculture andand anglers may be anglers may be possible vectorspossible vectors

Infectious salmonid Infectious salmonid anaemia (ISA)anaemia (ISA)

• Major outbreak in 1998-9 on west Major outbreak in 1998-9 on west coastcoast

• Many farms compulsory slaughterMany farms compulsory slaughter• Transfer to wild populations has Transfer to wild populations has

been reportedbeen reported• No real indications of effects on wild No real indications of effects on wild

populationspopulations• New codes of practice to minimise New codes of practice to minimise

future impactfuture impact

Infectious Pancreatic Infectious Pancreatic Necrosis (IPN)Necrosis (IPN)

• IPN is widespread in many farming IPN is widespread in many farming areas and it appears that it can be areas and it appears that it can be passed to wild stocks. However, passed to wild stocks. However, very few samples have been very few samples have been analysed from wild populations and analysed from wild populations and further monitoring is required to further monitoring is required to determine the degree to which determine the degree to which transfer is occurring and whether it transfer is occurring and whether it has significance for wild populations.has significance for wild populations.

The decline of wild salmonid The decline of wild salmonid populationspopulations

Declared wild salmon rod catch from the East, Moray, North East and North Statistical Regions, 1970-2000. Dashed lines represent average catches for 1970-1979 and 1991-2000. (Scottish Executive data).

Scottish marine salmon farm production and the combined declared wild salmon rod catch for the North West and West Coast Statistical Regions, 1970-2000

Butler, J.R.A. & Watt, J. (in press). Assessing and Managing the impacts of marine salmon farms on wild salmon in western Scotland: identifying priority rivers for conservation. Proc. 6th Int. Atlantic Salmon Symp., 'Salmon at the Edge', Edinburgh, UK, July 2002.

Annual Totals of Migratory Fish Counted at the Awe Barrage (1964-2001)

0500

100015002000250030003500400045005000

19

64

19

67

19

70

19

73

19

76

19

79

19

82

19

85

19

88

19

91

19

94

19

97

20

00

YEAR

CO

UN

T

COUNT

5 YEAR AVG.

Fyne District Salmon Fishery Board Rod Catch Records (1977-99)

0

200

400

600

800

1000

120019

77

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

YEAR

RO

D C

AT

CH

Escapees

Sea Trout

Salmon/Grilse

Sea liceSea lice

• Sea lice can be transferred from Sea lice can be transferred from farmed to wild stocks.farmed to wild stocks.

• Sea trout smolts can be infected Sea trout smolts can be infected with very large numbers (<10 with very large numbers (<10 fatal?)fatal?)

• Sea trout most at risk because of Sea trout most at risk because of their coastal lifestyletheir coastal lifestyle

• Sea trout extinct or under threat in Sea trout extinct or under threat in many west coast systemsmany west coast systems

Lice on a sea trout smoltLice on a sea trout smolt

Lousy salmon smoltLousy salmon smoltcaught in the open oceancaught in the open ocean

Left untreated, lice can kill Left untreated, lice can kill farmed farmed andand wild fish wild fish

Mean Lice Burdens (at Life Stage) of Sea TroutDunstaffnage Bay 2002

0

2

4

6

8

10

12

14

16

15th May 23rd May 11th June 20th June

Sample Date

Mea

n L

ice

Bu

rden

Ovigerous Females

Pre & Adult

Chalimus

Sea LiceSea Lice• Salmon smolts can be infected with large Salmon smolts can be infected with large

numbers of sea lice on route to the oceannumbers of sea lice on route to the ocean• > 86 % of the wild postsmolts migrating out > 86 % of the wild postsmolts migrating out

of the Sognefjord and 48.5 % - 81.5 % from of the Sognefjord and 48.5 % - 81.5 % from the Nordfjord were killed by sea lice during the Nordfjord were killed by sea lice during the spring of 1999the spring of 1999

• Many west coast rivers show declining Many west coast rivers show declining returns of salmonreturns of salmon

• Absolute proof is lacking but many scientists Absolute proof is lacking but many scientists consider that lice from farms are at least consider that lice from farms are at least part of the problem facing wild populationspart of the problem facing wild populations

River Awe SalmonRiver Awe Salmon

StrategiesStrategies

• Regular monitoring of lice numbers Regular monitoring of lice numbers • Co-ordinated chemical treatments Co-ordinated chemical treatments

between farms sharing the same water between farms sharing the same water bodybody

• Single generation sitesSingle generation sites• Fallowing of management areas to break Fallowing of management areas to break

lice cycleslice cycles• Treatment of lice in the spring when lice Treatment of lice in the spring when lice

numbers are lownumbers are low

Area Management Area Management AgreementsAgreements

• Fish farmers and wild fish interestsFish farmers and wild fish interests• The establishment of trusting The establishment of trusting

relationships!relationships!• A welcome startA welcome start• But seriously hampered in many But seriously hampered in many

cases by confidentially of information cases by confidentially of information regarding lice numbers on farms etc.regarding lice numbers on farms etc.

FutureFuture

• Although lice are now easier to Although lice are now easier to control with better medicines, control with better medicines, models indicate that continued models indicate that continued increases in production will result in increases in production will result in a continued threat.a continued threat.

• Relocation of farms away from Relocation of farms away from “important” rivers.“important” rivers.

• How far away?How far away?• Vaccine – a long way off.Vaccine – a long way off.

EscapesEscapes

• Farmed fish escape and can Farmed fish escape and can interbreed with wild populations interbreed with wild populations thus diluting local adaptations with thus diluting local adaptations with potential impact on fitness of potential impact on fitness of progenyprogeny

• Farmed fish are often found and Farmed fish are often found and caught in rivers caught in rivers

Farmed escapes can overwhelm Farmed escapes can overwhelm wild populationwild population

• If 1% of the farmed population escapes If 1% of the farmed population escapes each year then, for the west coast of each year then, for the west coast of Scotland only, that will amount to over Scotland only, that will amount to over 200,000 fish (in 2000)200,000 fish (in 2000)

• Total wild catch for the west coast was Total wild catch for the west coast was 8459 in 2000. Probably relates to about 8459 in 2000. Probably relates to about 60,000 returning fish60,000 returning fish

• Recorded escapes in 2000, approx 200,000Recorded escapes in 2000, approx 200,000• Not known how many actually successfully Not known how many actually successfully

enter rivers and breedenter rivers and breed

Escapes - conclusionEscapes - conclusion

• Even though farmed fish may be Even though farmed fish may be reproductively inferior, severe reproductively inferior, severe genetic dilution is possible genetic dilution is possible especially where escapes are especially where escapes are frequent and large, and local frequent and large, and local populations are small.populations are small.

Solutions?Solutions?

• Better containmentBetter containment• Genetic modification to induce sterility Genetic modification to induce sterility

(e.g. triploidy – although there are (e.g. triploidy – although there are problems)problems)

• Better methods of tagging fish (some Better methods of tagging fish (some good cheap methods are now available)good cheap methods are now available)

• Better understanding of fitness Better understanding of fitness consequences (recent work by consequences (recent work by Ferguson)Ferguson)

Feed suppliesFeed supplies

• Salmon feed is largely fish meal Salmon feed is largely fish meal and fish oil sourced from small, oily and fish oil sourced from small, oily fish caught in the great industrial fish caught in the great industrial fisheries of the world, e.g. N. fisheries of the world, e.g. N. Europe, South America.Europe, South America.

• World capture fishery production World capture fishery production has plateaued (against a has plateaued (against a background of increasing fishing background of increasing fishing effort) at around 86 - 94 Mt of effort) at around 86 - 94 Mt of which 23 - 33 Mt are used annually which 23 - 33 Mt are used annually for the production of fish meal and for the production of fish meal and oil .oil .

• Are these fisheries sustainable? Are these fisheries sustainable? Few fisheries are!Few fisheries are!

• Discards = 27MtDiscards = 27Mt

How do we fill the gap?How do we fill the gap?

• Increased substitution of vegetable Increased substitution of vegetable oils and meals – much research is oils and meals – much research is underway particularly regarding underway particularly regarding omega-3 fatty acid requirements omega-3 fatty acid requirements (EPA, DHA) and also on amino (EPA, DHA) and also on amino acids in plant mealsacids in plant meals

• More efficient use of processed More efficient use of processed wastes and discardswastes and discards

Key conclusionsKey conclusions

• The supply of nutrients to the marine The supply of nutrients to the marine environment is unlikely to be the environment is unlikely to be the factor that limits the scale of fish farm factor that limits the scale of fish farm production in the foreseeable future.production in the foreseeable future.

• More likely to limit production are the More likely to limit production are the linked issues of medicine usage and linked issues of medicine usage and sea lice transfer to wild populations. sea lice transfer to wild populations.

• The rate of escapes of farmed salmon is The rate of escapes of farmed salmon is probably unsustainable and represents probably unsustainable and represents a major threat to wild populations. a major threat to wild populations.

• Changes in fishmeal supply may affect Changes in fishmeal supply may affect the sustainability of the industry in the the sustainability of the industry in the short-term but substitutes for fish short-term but substitutes for fish meal/oil are actively being developed to meal/oil are actively being developed to fill the medium-term gap in supply. But fill the medium-term gap in supply. But feed supply will become a crucial issue!feed supply will become a crucial issue!

Aquaculture StrategyAquaculture Strategy

• A crucial need is for the development of A crucial need is for the development of truly Integrated Coastal Zone truly Integrated Coastal Zone Management where transparent cost-Management where transparent cost-benefit analyses can help to reassure ALL benefit analyses can help to reassure ALL resource users that the best possible use resource users that the best possible use use is made of our invaluable marine use is made of our invaluable marine resource.resource.

• Aquaculture must be nested into such a Aquaculture must be nested into such a system at the basin scale level and not system at the basin scale level and not treated in isolation.treated in isolation.

Thanks to Alan Kettle-White, Kate Thanks to Alan Kettle-White, Kate Willis, James Butler and Jens Willis, James Butler and Jens

Christian Holst for use of images and Christian Holst for use of images and data.data.

Thanks to the British Council andThanks to the British Council and Dror Angel Dror Angel

And thanks to you for your attention And thanks to you for your attention

http://www.scotland.gov.uk/cru/kd01/green

/reia-00.asp