Environmental Impacts of Salmon Farms: Lessons from New Brunswick Inka Milewski Science Advisor...
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Environmental Impacts of Salmon Farms: Lessons from New Brunswick Inka Milewski Science Advisor Conservation Council of New Brunswick June 27, 2011 Shelburne,
Environmental Impacts of Salmon Farms: Lessons from New
Brunswick Inka Milewski Science Advisor Conservation Council of New
Brunswick June 27, 2011 Shelburne, Nova Scotia
Slide 2
Environmental Impacts of Salmon Farms Known potential impacts
include: Increased suspended solids, turbidity and sedimentation
Nutrient loading Degradation of water quality from hazardous
materials Impacts to fish and fish habitat Disease transmission
Invasive species, which could alter ecosystem dynamics Interference
with traditional use of resources Disruptions of wildlife and
wildlife habitat, including migratory birds and species at risk
Impacts of odour and noise on humans Source: Transport Canada.
2011. Environmental Assessment Screening Report for proposed sites
in St. Marys Bay
Slide 3
Environmental Impacts of Salmon Farms By volume, largest
component of waste released from a salmon farm is organic (fecal
and uneaten feed) waste and nutrient (nitrogen and phosphorus)
Slide 4
Carbon and nitrogen releases to the LEtang Inlet, New Brunswick
2002 SourcesCarbon (mt per year) Nitrogen (mt per year) Salmon
Farms 22 farms (APL 4.44 million fish) 949 2372.5 259.1 657.0
Sewage plant (servicing 1200 people)51.110.9 Pulp Mill138.74.1 Fish
plant (sardine processing plant)1525.7273.7 Runoff from
land299.310.95 Precipitation-18.2 Source: Strain and Hargrave.
2005. Salmon aquaculture, nutrient fluxes and ecosystem processes
in southwestern New Brunswick. In. Hargrave (ed.) Environmental
Effects of Marine FInfish Aquaculture: The Handbook of
Environmental Chemistry Vol 5.
Slide 5
Impacts of Organic (Carbon) Waste Sediments and the water
column above become oxygen depleted and toxic Diversity of animals
in and on the sediment drops; white bacterial mats cover the bottom
Food chain connecting the benthic (bottom- dwelling) and pelagic
(free-swimming) communities becomes uncoupled
Slide 6
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Increase in annual seaweed biomass increased incidence of toxic
phytoplankton blooms localized oxygen depletions loss of perennial
submerged aquatic vegetation (e.g., rockweed, eelgrass) a shift
from filter-feeding (clams, mussels) to deposit- feeding (worms)
animals increased disease in fish, crabs, and/or lobster Impacts
from Nutrient (nitrogen and phosphorous) Waste
Slide 8
Crow Harbour/Penn Island, New Brunswick Study 2002-2004
Slide 9
Control site Former Fish Farm Site Crow Harbour/Penn Island,
New Brunswick Study 2002-2004 July 2000 site ~ 295,000 smolt put
into 21 net pens covering an area of ~19 ha April 2002 harvesting
began July 2002 final feeding August 2002 last fish harvested
August 24, 2002 benthic survey began ~ 5 months after most
intensive feeding period and 3 weeks after last fish harvested
Sampled again on August 27, 2003 and August 23. 2004
Slide 10
Sediment core sample coming on board and testing
Slide 11
2002 Crow Harbour benthic samples 2002 Control Site benthic
samples Black sediments indicate a lack of oxygen and the presence
of anaerobic bacteria.
Slide 12
Reference/Control site 2003 Penn Island/Crow Harbour farm site
2003 Penn Island/Crow Harbour farm site 2004
Slide 13
Sediment Eh at a former fish farm in Crow Harbour and a
reference site (mean values of 3 samples) 2002-2004 Sediment Depth
Hypoxic Anoxic
Slide 14
Surface Sediment Sulfides at a former fish farm in Crow Harbour
and a reference site (2002-2004)
Slide 15
Reference Site Farm Site Number of species and diversity did
not recover at the farm site after two years
Slide 16
Environmental Monitoring of Salmon Farms only one environmental
measure is monitored sulphides in sediments DFO has not defined a
sulphide limit that results in mandatory regulatory action ; HADD
authorization may be required at 4500-6000 M 40-60% biodiversity
reduced at 500 to 1500 M sulphides 60-70% reduced at 1500-3000 M
70-90% reduced at 3000-6000 M 90% reduced > 6000 M
Slide 17
Slide 18
Environmental Monitoring of Salmon Farms In New Brunswick Prior
to 2006, remediation plans were required when sulphides reached
1300 M In 2006, remediation required when benthic sulphides reach
1500 m Site must do more monitoring and submit report when
sulphides are 3000-4500 M and may be required to get HADD
authorization from DFO Annually, 20% of NB farms require
remediation plans
Slide 19
2006 Salmon Farm Sites
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2006 NB Action Level 2001 NB Action Level
Slide 23
2009: 2111.7 M sulphides 2010: 1442 M sulphides Control site
Former Fish Farm
Slide 24
Nova Scotia Environmental Monitoring Program (EMP) First EMP
began in 2002 Plan was updated in March 2011 EMP is focused on
monitoring sulphides EMP approach is increased risk requires
increased monitoring Sites with 50% of sampling stations with 1500
M sulphides need more sampling and must adjust their Best
Management Practices (BMP) to improve site performance Sites with
50% of sampling stations with 3 000 M of sulphides need more
sampling and operator must submit a mitigation plan for maintaining
or increasing production levels Sites with 70% of sampling stations
with 6 000 M sulphides must work with regulators to examine
mitigation options; some site may require DFO authorization to
allow a (HADD) harmful alteration, disruption or destruction of
fish habitat on the site
Slide 25
2011 NS more monitoring and enhanced management
Slide 26
2011 NS more monitoring and enhanced management level
Slide 27
Nova Scotia Environmental Monitoring Results Brier
Island/Westport
Slide 28
Beyond the farm impacts Bay-wide (Cumulative) Effects from
multiple salmon farms Sampled 1994-1999 examined sediment carbon,
microbial biomass and biological diversity 1994-95 results showed
area was strongly impacted 1996-1997 salmon farming stopped due to
ISA outbreak; Re-sampled in 1997 and 1999; carbon and bacteria
levels declined, no recovery in the biological community farm
operations had an effect on benthic habitat beyond the farm area
Pohle et al. 2001. Assessment of regional benthic impact of salmon
mariculture within the Letang Inlet, Bay of Fundy. ICES Journal of
Marine Science 58: 417426. 2001
Slide 29
For Lime Kiln Bay, salmon farms release 3.3 times more nitrogen
and 1.6 time more carbon is cycled naturally in the water column
and sediments. substantial changes to the functioning of the
ecosystem have occurred due to the presence of the salmon farms
Even in a larger, less intensively farmed area like the Campobello
/ Deer Island, fluxes of carbon and nitrogen from salmon
aquaculture are 10 and 16 %, respectively, of those due to natural
processes. Local impacts can be much greater than those measured on
large scales Source: Strain and Hargrave. 2005. Salmon aquaculture,
nutrient fluxes and ecosystem processes in southwestern New
Brunswick. In. Hargrave (ed.) Environmental Effects of Marine
FInfish Aquaculture: The Handbook of Environmental Chemistry Vol 5.
Beyond the farm impacts Bay-wide (Cumulative) Effects from multiple
salmon farms
Slide 30
Regulations and Management of Impacts? Inadequate and
Incomplete information for managing ecosystem effects are currently
incomplete multiple measures will be the most effective for
managing ecosystem effects of aquaculture management focused
primarily on near-field and site-specific regulatory applications
far-field and cumulative effects could occur and will require new
or modified management tools Benthic monitoring is less suitable
for farfield monitoring finfish aquaculture has the potential to
alter the trophic (food web) status of bays Mass balance
calculations can be used to estimate the portion of aquaculture
wastes to a system compared to nutrients from other sources
Slide 31
Our Oceans and Coasts in Trouble A decline in many fish stocks
has occurred on the Atlantic and Pacific coasts as a result of
commercial overexploitation. Industry and development have, or are
threatening to, impact most ecosystems. The coastal zone is
particularly vulnerable and is of concern as these areas are
considered highly productive ecosystems.
Slide 32
Need for sustainable aquaculture Activities that do not degrade
the ecosystem on which they depend including: preserving the form
and function (ecological relationships) of natural systems
preventing nutrient, chemical and biological pollution ensuring no
net loss of protein Source: Bardach, 1997: Sustainable Aquaculture.
New York; John Wiley & Sons Costa-Pierce, 2002. Ecological
Aquaculture: The evolution of the blue revolution Oxford: Blackwell
Science