Once the mainstay of New England fisheries, Atlantic cod has struggled to come back from record low levels. Recently, collaborative research programs have brought together fishermen and scientists to answer key questions
The Northeast Regional Cod Tagging Program is one such effort. In March 2003, the Gulf of Maine Research Institute (GMRI) launched the program with a goal of tagging 100,000 Atlantic cod from Nova Scotia to Cape Cod and out to Georges Bank, in hopes of gaining a better understanding of cod movements in the region. Funded by the National Marine Fisheries Service, the tagging has been carried out by an international partnership of research organizations including the Maine Department of Marine Resources, Canada’s Department of Fisheries and Oceans, the Island Institute, the Cape Cod Commercial Hook Fishermen’s Association, the School for Marine Science and Technology at the University of Massachusetts-Dartmouth and Manomet Center for Conservation Sciences.
Thanks to over 250 fishermen working with nearly 25 scientists, the Northeast Regional Cod Tagging Program has succeed in tagging over 103,000 Atlantic cod.
“I’m delighted that we have exceeded our tagging goal due to the hard work of hundreds of fishermen and scientists along the coast of the Gulf of Maine,” said Shelly Tallack, program manager. “However, the ultimate ability of this Program to provide reliable information on the movement patterns of cod is solely dependant on the continued support of the region’s fishermen by continuing to report recaptures of these tagged fish.”
The migration of Atlantic cod is still not well understood. These fish migrate from wintering grounds into summer spawning and feeding grounds, which may take them across a number of areas worked by different fishing fleets. In an effort to understand just how much cumulative impact this fishing effort has on the whole stock, and to understand if there are population sub-units that may need conservation, information about these movements is critical.
Tags need to be returned in large enough numbers to provide meaningful results. Returns have risen steadily over the months and the current return rate is 2.6 percent based on approximately 2,600 recaptures. Sixty percent of the returns are reported by mail, though fishermen can call in using a toll free number (1-888-447-2111), or by emailing a tag return to codresearch@gmri.org. These returns are already providing valuable information, but an accurate future analysis will depend on a high return rate of these tags. Fishermen also receive a reward, in the form of a mug, hat or shirt, for each tag returned. There is also a cash lottery taken from the pool of tag returners, and special tags, blue in color, are all worth an automatic $100.
Despite increasing tag returns, there is concern about the considerable variation in the number of tags reported from each region. “This variation does not necessarily reflect cod abundance or fishing effort for these areas. As such, the current data could misrepresent the movement which is actually occurring,” observed Tallack. For example, the number of tags released by the Canadian partners is approximately 5,600, or 5.6 percent of the total tag releases. However, Canadian fishermen and processors have reported approximately 21 percent of the total number of tag returns and their information shows a strong movement of cod from Georges Bank into the Bay of Fundy and other Canadian Maritime waters. In contrast, fewer tag returns to date show a southerly movement into American waters. While this data could reflect the true primary direction of movement, it may also suggest variation in tagging reporting.
“It is important for fishermen who are sceptical about this Program and how its data will be used,” Tallack warned, “to understand that skewed data will only compromise the accuracy of the final result, which in the long run, will not best serve the fishery.”
For further information please visit the website www.codresearch.org.