Massachusetts DMF Studies Scaled-Back Dogfish Fishery

By David Pierce, Ph.D., Assistant Director of the Massachusetts DMF 

This past summer DMF devoted time and resources to sample spiny dogfish commercial fishery catches and landings. We made a commitment to do this sampling as part of our management approach for the dogfish fishery in state waters this year. 

DMF and the Massachusetts Marine Fisheries Commission provided for a 7 million lbs. dogfish fishery to preserve some of the commonwealth's dogfish processing infrastructure and market that would have been lost entirely and for almost 20 years under new federal restrictions. We set this limit after examining other options to a complete closure and finding one that would provide for a small-scale directed fishery. The fishery management councils' scientific/technical advisors (Dogfish Technical Committee) recently concluded our alternative is equivalent to the federal plan's stock rebuilding program. 

Our approach for managing this fishery in state waters involved permit requirements, a 31" minimum size, no overnight setting of gillnets, restrictions on gillnet length and number of nets, and a 7,000 lb. daily landing limit. For the past decade dogfish have been important to fishermen from ports of Scituate, Plymouth, and Chatham and fish processors in New Bedford. DMF closed the fishery on Aug. 26 after we projected that the 7 million lbs. would be landed by that date. The closure will last until the end of the management councils' fishing year, April 30, 2001. Seven million lbs. is a far cry from recent year's landings of 45-50 million lbs. Yet, industry was able to sustain this very modest dogfish fishery because price per pound rose to about 25 cents from the usual 5 cents. 

When we implanted our alternative, we pledged to use the directed fishery as an opportunity to obtain basic information about the fishery that could be used to improve stock assessments. Critical biological information for stock assessments, such as fish length and age data from fishermen's catches, is lacking. Biological sampling efforts for many species are declining throughout the region. 

Currently, the stock assessment relies almost entirely on results from springtime Northeast Fisheries Science Center bottom trawl surveys extending from North Carolina to the U.S./Canada border. The assessment also uses DMF's trawl survey of state waters. Federal estimates of fish abundance (biomass) are gauged from a swept-area approach involving the number and weight of dogfish "swept up" in the area covered by 20 minute trawls tows expanded upwards to the total square area of coastal and offshore ocean bottom over which dogfish roam. Dogfish are migratory seasonally moving up and down in the water column and along the coast with cross-over into Canadian waters. 

Because very little is known about the sizes of dogfish landed and processed, DMF devoted staff to sampling processing plants in New Bedford. This involved our having to temporarily assign some of our staff to do this important work. Even this author found himself along side a measuring board. Our task was made easier by processors anxious to help us obtain what we needed to better understand landing composition (length by sex) and to improve future stock assessments. They welcomed us and cooperated in every way. 

On 13 occasions from July 17 through Aug. 9 we sampled New Bedford processing plants. About 13,000 lbs. were sampled and 2,800 fish measured. Sizes of dogfish ranged from about 67-104 cm (26-41 inches). 

In addition to our port sampling, DMF observers sampled fishermen's catches at sea. Eight trips were made on dogfish long liners and gill-netters fishing in Cape Cod Bay and east of Cape Cod within the 3-mile limit. Catch and by-catch composition, and dogfish size distribution were documented. Like the processors, vessel captains were very helpful. 

A report of our sampling activities and results will soon be released. The results will be forwarded to scientists, the management councils and the Atlantic States Marine Fisheries Commission (ASMFC). ASMFC is developing an interstate management plan for dogfish. A plan for federal waters already exists. 

One argument for our continuing a small-scale directed fishery is it provides the means by which we can better assess dogfish abundance - the status of the stock. 

Assuming we have a similar fishery next year, we intend to continue and perhaps expand our sampling and enlist other states to do the same. Even some members of the industry have offered to pay for research and to involve fishermen and processors in the data-gathering. To us it's clear there's much to be gained for cooperative work with fishermen. It's our intent to work with the industry to better understand the impact of the fishery on the resource and to respond with appropriate restrictions.