Successful fisheries management requires accurate information on where fish live, how quickly they grow, what they eat, and what eats them. We are conducting studies of the ecology of many of the important commercial species in the Gulf of Maine, including cod, haddock, herring, monkfish, alewife, bluefin tuna, and lobsters.
Many of our research projects involve analyzing otoliths, a small bone located in the ears of fish. These bones have annual growth rings, similar to the rings of a tree. When counted under a microscope, they reveal the age of the fish. Careful aging allows us to understand how quickly fish grow and whether their growth rate changes from year-to-year or place-to-place.
We can also analyze the chemical signature stored in the otoliths to determine where a fish was born. Most fish populations are composed of several discrete stocks that reproduce in different places or during different seasons. Understanding how these stocks mix is a major challenge for fisheries management, and failure to correctly account for stock structure can lead to overfishing of one or more of the stocks.
In addition to otolith chemistry, we use information from tagging studies and subtle differences in fish body shape to understand stock structure and mixing. We also employ the use computer models to understand how stock mixing interacts with management of fisheries.