AQUACULTURE IN CANADA AND EFFECTS

OF HABS

Eutrophication and Harmful AlgaeDHIMAN GAIN

Contents Importance of Aquaculture in Canada Fisheries Production

Finfish Shellfish

Effects of HABs on Salmon production Effects of HABs on Shellfish production Effects of Salmon production on HABs Occurrence of HABs Eutrophication status in Canada Hydrography (Lakes Vs Open sea) Identification of the HA sources Monitoring programs Summary and Conclusions

The importance of Canadian Aquaculture

Finfish SpeciesAtlantic SalmonChinook SalmonCoho SalmonRainbow Trout Steelhead TroutBrook TroutSpeckled Trout SturgeonSablefishArctic CharHalibutTilapia Cod

Shellfish SpeciesPacific Oysters

Eastern OystersBlue Mussels

Mediterranean MusselsManila Clams

Varnish/Savory Clams Clams

Japanese ScallopsSea Scallops

QuahogsAbalone

Source: Statistics Canada

2011 Production: Finfish: 123,567 tonnes and 763 M $ by value Shellfish: 38,646 tonnes and 74 M $ by value

Production of Finfish

Methods:Juveniles: land-based hatchery facilities (flow-through and recirculation);Grow-out: saltwater net pens, some land-based systems;Broodstock: land-based (flow through and recirculation)

Methods:- Juveniles: land-based hatchery facilities (flow-through and recirculation)- Grow-Out: freshwater net pens, saltwater net pens (for Steelhead culture), land-based raceways, and ponds- Broodstock: land-based (flow-through and recirculation)

Intensive (dry pellets rich in N &

P) open culture system

Production of ShellfishMethods:Ocean floor beds or off-floor suspension (holding bags, cages, trays or rope lines)

Methods:- Seed collection from the wild (method mostly used on the East Coast) or procured from hatcheries (method mostly used on the West Coast), -followed by grow-out to market size in mussel socks suspended from long-line systems (ropes) or rafts.

Extensive (natural feeding)

culture system

Effects of HABs on Salmon production

Cochlodinium sp.

Vancouver Island, BC

Farmed salmon

Toxic

• Cause of death is unknown • Oxygen radical production leading to gill and • liver damage is suspected.

Chaetoceros convolutus

Nanaimo , BC

• Physically damage the gills• Small spines cause capillary damage• Excessive mucus production • Suffocation and • Death

Ling-cod and farmed salmon

Non-toxic

Heterosigma akashiwo

Farmed salmon

Toxic

• Precise mechanism of death is uncertain• Release harmful substances into the water• Cause gill or liver damage• Excessive mucus production sometimes observed

British Columbia

Direct economic losses due to HABs in British Columbia

PICES SCIENTIFIC REPORT No. 47, 2014

Light grey for low level (up to 100 fish killed), dark grey for moderate (100–1000 fish killed), and black for high (more than 1000 fish killed

Effects of HABs on Shellfish production

Shellfish Poisoning

Alexandrium catenella &

Alexandrium tamarense

West & East coast of Vancouver Island, BC

Cause PSP Toxin: Saxitoxin

Pseudo-nitzschia spp.

Nitzschia spp.

Cause DAP or ASPToxin: Domoic acid

British Columbia

Dinophysis spp.

Prorocentrum lima

British ColumbiaCommon but not abundant

Cause DSPToxin: Okadaic acid or dinophysistoxin

Effects of Salmon aquaculture on HABs?

Finfish farming primarily increase organic matter sedimentation

Influence nutrient regeneration

Increase dissolved nutrients (N:60%, P:12)& influence seaweed growth

Create eutrophication which ultimately influence HABs

There is no evidence for direct links between HABs

and salmon aquaculture found in Canada

Occurrence of HABs in Canada

2000

Alexandrium tamarense

Akashiwo sanguinea

1978

Gonyaulax spinifera

1990

Heterosigma akashiwo

1989,91,93,97

Cochlodinium polykrikoide

1999

Nitzschia pungens

1988

Eutrophication status in Canada

In Canada total phosphorus concentrations were found to be high

The majority of phosphorus found in suspended sediment

TP and TDP have increases between 1990 and 2006, where TDP is the form that is readily available for take up by plants.

70% of the study sites with high levels of TP (eutrophic and hypereutrophic) were located in the Arctic and Nelson River basins. Status of phosphorus in the water bodies

across Canada (2004-06)

Hydrography-Aquaculture in lakes

Controlled by: Agricultural run-off Runoff from urban

expansion Sedimentation Less tidal circulation Water residence

time > flushing time

Hydrography-Aquaculture in open sea

High tidal exchange

Plankton can not stay in a certain place for long time

Residence time of water is very low

Aquaculture in the bays in Canada

Identification of the HA sources

MODIS satellite sensor for observing chlorophyll fluorescence

MODIS images for the Vancouver Island area (22/09/00)

Bloom of Heterosigma akashiwo in Kyuquot Sound, British Columbia

Monitoring strategies for HABs Biotoxin tests are carried out for: Saxitoxins(since the mid 1960's) Domoic acid by Canadian Food Inspection Agency Establishment of Harmful Algae Monitoring Program (HAMP) in 1999 to address the devastating effect of harmful algae on farmed fish. Phycotoxins Working Group since 1987 The Northcoast Plankton Identification and Monitoring ProgramSteps taken after positive result:

Closures of the affected area when found 80 μm saxitoxin /100 gm shellfish meat Systematic microscopic surveillance of water samples for early warning of HABs at

farm sites Isolate and culture microalgal species that are known to be harmful to cultured fish

and shellfish in BC Development of species-specific quantitative polymerase chain reaction (PCR)

assays, and creation of an image gallery and database of local harmful algae Carry out genomic analyses on shellfish gill tissues to determine genomic and

biological responses to HABs and to link these responses with particular algal species.

Butter clams are now permanently prohibited from collection along the entire coast of BC

Summary and Conclusions HABs (Harmful Algal Blooms) are responsible for

considerable economic losses due to cultured finfish/shellfish mortalities in Canada.

Toxic HABs in shellfish are a threat for human health. Since the mid 1980's the cumulative loss in

aquacultured salmonids of British Columbia is $35 million.

Fish farming change the nutrient ratio which has a great impact on the occurrence of HABs in that area.

Water body having higher residence time are more prone to HABs than less residence time area.

Finally, HABs can appear independently of fish farming activities.

References F.J.R. “Max” Taylor and Paul J. Harmful algal blooms in western Canadian

coastal waters Harrison University of British Columbia, 6270 University Boulevard, Vancouver, B.C., Canada V6T 1Z4.

J.F.R. Gower, L. Brown, and G.A. Borstad, 2004. Observation of chlorophyll fluorescence in west coast waters of Canada using the MODIS satellite sensor. Can. J. Remote Sensing, Vol. 30, No. 1, pp. 17–25.

DJ Martell, J Duhaime, and GJ Parsons (eds). Canadian Aquaculture R&D Review 2013. Aquaculture Association of Canada Special, Publication 23 (2013).

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