Predatory Consumption of Silver Hake Merluccius bilinearis in the Northwest Atlantic

The present study reports estimates of silver hake consumed by a wide range of fish predators commonly found in Northeast Fisheries Science Center bottom trawl surveys.  A forty-seven year database of stomach content data consisting of over 500,000 stomach samples was examined to estimate the per capita  and total consumption of silver hake by each predator Total population-level consumption estimates were based on the product of per capita rates times the predator abundance. Abundance estimates of predators were obtained from stock assessments whenever possible; swept-area based estimates were used otherwise.    These consumption estimates of silver hake are biased low because consumption by birds, marine mammals, large pelagic fish and organisms outside of the survey area were not included.  Results suggest that estimates of consumption by all consistent silver hake predators varied through time ranging between 4,000 mt in 1975 and to a peak of 165,000mt in 1985.  A majority of the consumption was attributed to goosefish and consisted mostly of silver hake less than 20cm. Although these estimates of predatory removals are likely conservative they were at least 5-10 times higher than the commercial removals of silver hake during the period 1973 to 2009.