(E5) Exercise #5: Gone Fishing
analyze annual fish landing, mortality, and biomass data; explain what caused the collapse of groundfish populations in New England; define the terms overfishing and overfished; understand how MPAs can be effective management tools for preventing and reviving overfished populations; and examine your role as a consumer in aiding the sustainability of fish in our oceans.
For as long as people have lived near water, people have fished. Sadly, in many instances, the history of fishing is paralleled by a history of overfishing. According to the 2006 Report of Status of U.S. Fisheries, 20% of U.S. fish stocks with known overfishing status are subject to overfishing and 25% of stocks with known overfished status are considered to be overfished. An additional four stocks currently classified as not overfished are approaching overfished status. Contributing factors to the current level of overfishing include:
technological advances that have made large-scale fishing easier; too many fishing boats on the water; international partnerships that allow foreign fleets to overfish in the waters of developing countries; illegal fishing that violates fishing laws or agreements; large amounts of bycatch of juvenile fish and non-target species; and the shortcomings of fisheries conservation and management efforts.
The impacts of declining fish catches are being painfully felt by many coastal fishing communities around the globe. Jobs are lost and food is scarce. Impacts are also felt in the oceans as other marine species are left with fewer fish to eat. Overfishing affects the entire marine food web. But how do know when overfishing is occurring or when a stock is overfished? More importantly, can these conditions be reversed?
Part 1: Overfishing in Georges Bank
Georges Bank is an underwater bank situated along the eastern edge of the Gulf of Maine between Cape Cod and Nova Scotia. This region is one of the most biologically productive marine areas on the eastern seaboard, historically accounting for a large percentage of New England’s commercial fish landings. The Georges Bank fishery is particularly well-known for its groundfish—species such as cod, haddock, and flounder that feed near the bottom of the ocean.
Look at the graph on the next page of trends in Georges Bank haddock catch and mortality from 1969 through 2004.
The histogram shows the annual haddock landing—the amount of fish that are caught and kept to sell. The red line shows the fishing mortality rate, F—the rate at which fish are removed from a population due to fishing (as opposed to removals due to natural causes such as disease or predation). F can also be thought of as the percentage of a population that die in one year due to fishing.
Map of the Gulf of Maine; Georges Bank is the light blue region in the bottom center of the image. Image courtesy of NOAA and U.S. Geological Survey (USGS) Woods Hole, MA. Labels by Syagria.
(1) Describe the trends you see in the Haddock landings from 1969-2004. Are there steady trends or distinct turning