Atlantic Salmon Salmo salar

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Atlantic SalmonSalmo salar

• A species indicator?

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Atlantic salmon Life Cycle
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Wild Atlantic Salmon migration routes
Source The Wild Atlantic Salmon-State of the
Population in North America 2000 (www.asf.ca)
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• Salmon spawn any time between mid October to mid
  or late November.
• Each female can produce between 1500-1800
  eggs/kg/body weight
• Once the female has located a site, she prepares
  a redd (nest).

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Introduction

• The Atlantic salmon is born in fresh water
  remains there until it undergoes a physiological
  transformation allowing it to tolerate salt
  water.

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It is during the smolt stage that the salmon will
leave the fresh water river migrate to the salt
water sea. The smolt stage would be the
equivalent of our adolescent stage of
development.

• The ALEVINS (hatchlings or fry) PARR (yolk sac
  is gone actively feeding free swimming) will
  stay in the freshwater system for usually 2-3
  years before reaching the SMOLT stage.

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After 1-3 years at sea, the salmon returns to its
river of origin (where it was born!) to spawn
(reproduce). They are now called grilse. Others
will remain in salt water to overwinter another
season will return to fresh water to spawn as
adult salmon. (gt63 cm)
The soils vegetation along the streams rivers
play an important role in protecting
maintaining salmon habitat.
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The vegetation both nourishes the river ecosystem
protects it by stabilizing the riverbanks,
preventing them from collapsing silting the
river.
A good spawning site will have coarse, loose
gravel 3-7 cm thick, a moderately strong current
to prevent eggs from being smothered by settling
silt, well-oxygenated water.
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of Fish
Time (year 19??)
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Atlantic salmon situation in Nova Scotia??

• 2002 FINAL Cumulative counts of MSW salmon on
  rivers of the Nova Scotia portion of the
  Maritimes Region, as of November 15, 2002 (Click
  here to learn more)

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Reasons for Species Loss

• Siltation
• Altering/diverting Water Flow
• Erecting Dams or Barriers
• Altering/destroying Riverside Vegetation
• Altering/destroying Riverbanks

• Harvesting
• Illegal Harvesting
• Logging
• Aquaculture
• At-Sea mortality

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General Facts about Aquaculture

• In 1999, 70 000 tons of domestic salmon were
  raised in Canada
• Presently approx 30 companies operating more than
  200 salmon farms on both coasts. (salmon
  rainbow trout are preferred choice)
• Slightly more than 33 of Canadas domestic
  salmon output comes from the Maritimes.

• 90 of Maritime production comes from
  Passamaquoddy Bay Grand Manan areas
• 10 from NS NFLD
• Aquaculture now accounts for more than 25 of all
  fish consumed by humans worldwide.
• Salmon farming is the fastest growing sector in
  world aquaculture.

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Dangers Presented by Aquaculture

• In 1997 approx. 300 000 Atlantic salmon were
  accidently released into Puget Sound, BC.
• In Norway, approx. 1.3 million salmon escape from
  farms every year (33 of the salmon spawning in
  coastal rivers in Norway are ESCAPED domestic
  salmon!)
• There are areas in Norway where escaped domestic
  salmon have completely engulfed the historic
  range of wild salmon.

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Domestic vs. Wild

• Selectively bred to grow faster (10X faster)
  tend to be larger more aggressive
• Scientists claim that a genetically engineered
  salmon could be grown up to 4 m in length weigh
  gt80kg!

• Atlantic salmon fare better in captivity than
  Pacific salmon
• Domestic salmon now outnumber wild salmon by a
  factor of 10 to 1
• Do domestic salmon fall under the category of GM
  foods?

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Current salmon farming practices involve open
netcages like these that allow fish to escape
pollution to flow freely into the surrounding
water.
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Problems associated with salmon farming

• Sewage
• Drugs
• Escapees
• Net loss

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Waste accumulates beneath salmon farms,
smothering the ocean bottom and choking out life.
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Salmon farm pollution

• Organic
• Main source is fish excrement uneaten food
• The accumulated waste can smother the organisms
  and set up anoxic (oxygen depleted) conditions in
  the seabed sediment.
• Nutrient-loading (N P)

• Chemical
• Antibiotics
• Pesticides
• feed additives
• paints used on netcages and boats to prevent
  marine growth (antifouling paints)
• disinfectants.

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Drugs used in the salmon farming industry

• A variety of chemicals, including antibiotics,
  pesticides and fungicides are used on salmon
  farms to treat disease outbreaks.
• These drugs are often administered to the fish
  through their feed.
• Since salmon are mostly raised in open marine
  netcages, most of the drug, or its metabolic
  byproducts, end up in the marine environment
  through uneaten feed or the salmon's excrements.
• The distribution and environmental impact of
  these chemicals is a cause of great concern.

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Escaping farmed salmon pose risks

• Escaped salmon can be carriers of disease and
  parasites, which pose a threat to wild salmon
  populations.
• When the species farmed is native to an area
  there may still be an impact from escaped farmed
  salmon breeding with populations of wild salmon
  that are genetically adapted to specific streams.
• In British Columbia there is a greater danger
  arising from the fact that most of the salmon
  farmed are Atlantic salmon. Evidence exists that
  escaped Atlantic salmon can breed in BC's wild
  streams. The potential negative consequences of
  this could be dramatic.
• average escapees in BC is 90,000 per year for
  the period 1990-2000.

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Net loss of wild fish to produce farmed salmon

• Salmon farming proponents often point out that,
  since the wild fisheries are collapsing, farming
  the oceans is necessary to feed a hungry world
• They claim that their industry can supply food
  while taking pressure off ocean resources. But it
  isn't that straightforward.
• The impact of aquaculture (farming of a seafood
  species) varies, depending on what species is
  farmed and what method is used.
• With regard to taking pressure off ocean
  resources, a key factor is whether the species
  being farmed is carnivorous or not.
• A total of 2.7-3.5 tonnes of wild fish are used
  to make 1 tonne of farmed salmon!
• The consumption of 6.2 tonnes of wild fish for
  each tonne of salmon produced not only means less
  food for humans, but also for the many ocean
  species that rely on these fish as part of their
  food chain. Currently, the continued expansion of
  salmon farming is not sustainable.

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Possible Remedies?

• Commitment on the part of Federal Provincial
  Governments
• It has been suggested that salmon farms be
  located entirely within land-based pens fed by
  salt water to create a closed containment system
  (aquaculture industry opposed this measure
  because of the costs associated with creating the
  pens)
• Sterile, all-female strains of domestic salmon
  could reduce threats to wild salmon from cross-
  breeding with farm escapees.
• it is only a matter of time before a suitable
  seed-based food concentrate can be used to
  replace marine protein for feeding domestic
  salmon (DFO)

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Sources

• A number of images in this presentation are from
  the Atlantic Salmon Federation website
• David Suzuki Foundation

• News Issues concerning Aquaculture Facts are
  located at the Nova Scotia Salmon Association

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Siltation

• Occurs when a riverbed is covered with fine
  particles.
• Destroys spawning areas smothers salmon eggs.
• Can cause gill abrasion
• Makes feeding more difficult because the fish
  cant see their food.
• Caused by
• poor or improper road construction
• Irresponsible logging practices
• All-terrain vehicles (ATVs) in riverbeds

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Altering/diverting Water Flow

• Water flow is either too high or too low for the
  salmon
• Affects spawning survival rates

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Erecting Dams or Barriers

• Creates barriers for migrating salmon
• Destroys spawning beds
• Example Kejimkujik National Park (dam erected in
  the 1940s which affected the rivers that drained
  this park)

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Altering/destroying Riverside Vegetation

• Reduces food supply to the river ecosystem
• Causes siltation

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Altering/destroying Riverbanks

• Causes floodingwhich leads to..
• SILTATION!

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Harvesting

• Native bands that use salmon for food
• The importance of fishing to Aboriginal
  communities is recognized by DFO given first
  priority AFTER conservation.
• Conne River Mikmaq are the only band in NFLD
  with a recognized food fishery.
• Innu Nation Labrador Inuit Association have a
  food fishery in Labrador.

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Illegal Harvesting

• Loss of fish stock due to poaching.

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Logging

• Aggravates flooding causes flash floods
  siltation of water bodies.
• Really impacts on eggs juveniles.
• Use of insecticides herbicides can also be a
  problem

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Aquaculture

• Declining commercial salmon industry has placed
  an emphasis on raising Atlantic salmon in
  artificial environments.
• A salmonid is a member of the salmon family which
  includes salmon, trout, and char.
• New Brunswick, Newfoundland Labrador are BIG
  players on the East coast.
• If farmed salmon (domestic salmon) escape they
  can introduce new disease new genes into a
  watershed producing offspring that are less
  suitable for survival.
• Escapees may also compete for same food
  resources.

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At-Sea mortality

• A result of .
• by-catch
• Global climate change (salinity temperature)
• Seal predation (suspected but unproven)