Trophic Ecology of Atlantic Cod: Insights from Tri-Monthly, localized Scales of Sampling Years 1 & 2
Project Leader: Theodore Ligenza, F/V Riena Marie
Additional Project Participants:
Frank Almeida, Researcher, Northeast Fisheries Science Center
Jason Link, Researcher
Brian Smith, Scientist, Northeast Fisheries Science Center

Final report
Project Website

The project examined the small scale variation of Atlantic cod feeding based upon tri-monthly stomach sample collections from a nearshore, localized region off Cape Cod, Massachusetts. The first objective was to relate any detectable changes in cod diet and amount of food eaten with changes in temperature, spawning, prey abundance, and major weather events, filling in the information gap between broad scale and in vivo laboratory studies. The second objective was to work cooperatively with the fishing industry to transform anecdotal information into quantitative data. Results suggest that the amount of food eaten by cod is generally stable throughout the year, except when pelagic forage fish migrate through the area. This corresponds to critical periods in the life history of cod. The temporal variation in diet composition remained remarkably consistent each year over the 28-months of the project, suggesting important feeding periods for cod, which correspond to environmental and biological cues. The diet is comprised primarily of several species of forage fish (e.g. Atlantic herring, sand lance, Atlantic mackerel, ophiuroids, Cancer crabs, and other small crustaceans.) Additionally, these results confirm the preference cod exhibit for prey such as herring, sand lance,and crabs. We infer that cod generally eat local forage fish and benthic macro-invertebrates and then supplement their diet by gorge feeding upon migrating pelagic species. (from project abstract)