Are bigger fish better?
That question is at the root of a collaborative research effort by scientists at the University of Maine and the Gulf of Maine Research Institute (GMRI). The project will look at how changes in the sizes of fish in a given population influence overall health and ability to resist external pressures such as fishing and climate change.
Andrew Pershing, a UMaine associate professor and ecosystem modeler at GMRI, will lead this groundbreaking study, which has received a three-year, $215,000 grant from the Lenfest Ocean Program. Pershing will be joined on the project by GMRI fishery ecologist Graham Sherwood and UMaine researcher Walt Golet. The team will build a series of computer models to examine the consequences of what is known as “fishing down the size spectrum.”
“As an animal gets bigger,” says Pershing, “its metabolism becomes more efficient, meaning that it requires less food to support each gram of tissue in its body. Consequently, removing a large fish may have a larger impact on the population than removing the same weight of smaller fish.”
The researchers will tailor their models to Atlantic cod and northern bluefin tuna, which are species that have been heavily exploited and are the target of national and international management efforts. The team will generate computer models of feeding, growth and activity costs. The project will look as a whole at the role of body size in fish communities, with an emphasis on understanding the impact of size-selected fishing on their resiliency. The goal is to generate recommendations for increasing the resiliency of the species through fishing quotas, spatial management or gear design that is targeted at shifting efforts away from specific sizes.
The Lenfest Ocean Program (www.lenfestocean.org) funds scientific research on policy-relevant topics concerning the world’s oceans.
GMRI, which is based in Portland, is a nonprofit marine science center that works to find solutions to the complex challenges of ocean stewardship and economic growth in the Gulf of Maine bioregion. For more information, go to www.gmri.org.