Wednesday, January 7, 2015 (518) 402-8000
DEC
STUDYING ONGOING SALMON RIVER STEELHEAD DISORDER
Nutritional
Deficiency Strongly Implicated in Increased Steelhead Mortality in Lake Ontario
Tributaries
DEC Taking Steps
to Meet Egg Quotas to Ensure Robust Steelhead Population
Adult steelhead (a strain of rainbow
trout) returning from Lake Ontario to the Salmon River in Oswego County are
exhibiting signs of stress and elevated mortality rates due to an apparent
thiamine (vitamin B) deficiency, New York State Department of
Environmental Conservation (DEC) Commissioner Joe Martens announced
today.
DEC scientists enlisted the help of
fish health experts in other agencies and academia to determine the cause of
this disorder. DEC staff submitted moribund Salmon River steelhead to the
Cornell University Aquatic Animal Health Program for testing. Results indicate that fish pathogens are not
responsible for the abnormal behavior and mortality. DEC also sent steelhead samples to the U.S.
Geological Survey’s Northern Appalachian Research Laboratory for further lab
testing. Results strongly indicate a
severe thiamine (vitamin B) deficiency, which means it is likely contributing
to the steelhead mortality.
“Lake Ontario steelhead are an
important component of Lake Ontario’s sport fishery and DEC is deeply concerned about reports of
steelhead stress and mortality in the Salmon River and other Lake Ontario
tributaries,” Commissioner Martens said.
“Steelhead provide high-quality sport fisheries in the open lake and are
especially sought after by anglers who fish in tributaries from fall through
spring. DEC staff will continue to work
closely with federal agencies, Cornell University and other stakeholders to
identify the cause of the current situation and strategies to ensure a robust
steelhead population.”
In mid-November, DEC fisheries
staff began to receive reports of steelhead swimming erratically in the Salmon
River and higher mortality of the species.
More recent reports indicate similar behavior in steelhead in other Lake
Ontario tributaries.
Steelhead are an important
component of Lake Ontario’s sport fishery, which a Cornell University study
valued at over $112 million in angler expenditures in New York annually.
Great Lakes fish predators (including salmon
and steelhead) that feed primarily on alewife are prone to thiamine
deficiency. Alewife, an invasive bait
fish in the Great Lakes, are known to contain thiaminase, an enzyme that
degrades thiamine. A thiamine deficiency
can impact egg quality and the survival of eggs and newly hatched fish, and, in
severe cases, can cause the death of adult fish.
(MORE)
-2-
DEC is taking steps to meet its
spring 2015 steelhead egg-take targets at Salmon River Hatchery, and will work
with Great Lakes agency partners to provide assistance in meeting egg take
quotas, if needed. Staff
from DEC’s Rome Fish Disease Control Unit and Salmon River Hatchery are
preemptively injecting adult steelhead returning to the hatchery with
thiamine. Thiamine-injected fish will be held in outdoor raceways at the
hatchery and fed a diet fortified with vitamin B to improve the likelihood of
successful steelhead egg collections in 2015.
However, little can be done to
alleviate the mortality of adult steelhead that are unable to ascend the river
and reach the hatchery’s holding facilities. Although moderate thiamine
deficiencies are not uncommon in top predator fish such as salmon, lake trout
and steelhead in Lake Ontario and other waters, this year’s acute deficiency is
atypical in its severity. DEC staff will continue to collaborate with
experts to further understand the circumstances leading to this year’s
mortality.
For more information, contact DEC’s Bureau of Fisheries (Cape
Vincent Fisheries Station) at (315) 654-2147.
###