The close proximity of Massachusetts to the cooler boreal waters of the Gulf of Maine and the warmer temperate waters south of Cape Cod attract the seasonal feeding aggregations of a variety of big-game fish species. Extensive offshore fisheries for tunas, sharks, and marlin occur annually off Massachusetts' coast from June through October. Recreational anglers in private and chartered vessels travel miles offshore to catch bluefin, yellowfin, albacore, and bigeye tunas; blue, mako, and thresher sharks; and blue and white marlin. The highly migratory nature, large size, and long life span of these species render data acquistion and biological studies expensive and difficult to execute.
Since 1987, Massachusetts Division of Marine Fisheries (DMF) biologists have utilized the efforts of tournament fishermen to learn about the species and size composition, basic biology, and relative abundance of big game species off of our coast. Offshore fishing tournaments not only provide catch data and biological samples, but also estimates of effort which are often lacking for offshore recreational fisheries.
The number of tournaments held in Massachusetts fluctuates from year to year, depending on the economic climate and nature of the fisheries. There are generally about five to nine offshore tournaments held annually, with most located on Cape Cod and the Islands. Some target strictly sharks, while the majority offer prizes for a variety of species. All of the events self-impose minimum sizes and bag limits while promoting tag and release. Points can be garnered in most cases by not only weighing fish, but also by releasing them. Traditional tournaments like the Nantucket Billfish Tournament (29 years), the Green Harbor Tuna Tournament (25 years), the Oak Bluffs Monster Shark Tournament (11 years), and the Falmouth Grand Prix (8 years) have evolved over the years to changing economies and shifting fisheries but still provide valuable time series data for the DMF Tournament Program.
Although tournament data have been traditionally used by several states and the federal government to monitor landings in offshore recreational fisheries, the Massachusetts Tournament Program is unique. While most of these entities collect data on fish that are landed, the DMF program attempts to collect total catch data including fish that are boated, tagged, released, or lost. By working closely with tournament sponsors and tournament participants, DMF biologists not only assist in the development of the event but also facilitate complete data collection. When developing an index of abundance like catch per unit effort (CPUE), estimates of total catch allow the calculation of a more accurate index. This is particularly important when indices of abundance are used to monitor annual changes in fishing success.
From 1987 through 1997, DMF personnel have collected data at 73 big-game tournaments representing 34,736 boat hours of fishing effort. Over this period, 8,935 fish comprising 18 species have been tallied by the program. The dominant offshore species in the database is the blue shark, representing 68% of the tournament catch. Other species in the catch include, but are not limited to: yellowfin tuna (11%), white marlin (7%), bluefin tuna (4%), albacore tuna (3%), and mako shark (3%).
As expected, the percentage of fish released by tournament anglers during this period differed greatly by species, ranging from 0% (dolphin) to 97% (white marlin). Overall, only 18% of the total tournament catch was boated, while 63% was released and 19% was tagged when released.
Annual estimates of CPUE can be calculated to show trends in fishing success. Drastic fluctuations in CPUE may be indicative of changes in regional fish abundance caused by corresponding changes in prey availability, fish population size, and/or environmental factors. For example, the CPUE time series for yellowfin tuna shows that fishing success for this species was strong in 1993 and 1994, peaked in 1995, dropped out in 1996, and bounced back slightly in 1997. While mako shark CPUE has remained low, yet relatively stable over the eleven year period, blue shark fishing success has steadily increased. This increase may reflect an actual change in blue shark abundance, but better reporting attributable to tournament release categories has also affected this index.
The comprehensive catch and effort data collected by the Tournament Program are forwarded annually to the National Marine Fisheries Service for inclusion in their national statistics. Well-founded fisheries management decisions must be based on a thorough understanding of the fisheries themselves. The Massachusetts Sportfishing Tournament Monitoring Program provides valuable information about our fisheries that contributes to this understanding.
Tournament organizers and those interested in additional information about the program should contact Gregory Skomal, Massachusetts Division of Marine Fisheries, Martha's Vineyard Research Station, P.O. Box 68, Vineyard Haven, MA 02568, 508-693-4372, Or email to: gskomal@whsun1.wh.whoi.edu