River Herring Project
The goal of this project is to help the small mesh bottom trawl (SMBT) herring fleet avoid river herring (Alewife and Blueback Herring) bycatch by understanding the daily variation in river herring catches. Low river herring stocks have raised concerns among some groups. Some proposals currently being brought to the council could shut down or severely limit fishing in important SMBT herring fishing grounds and/or institute industry financed 100% observer coverage.
During this project Study Fleet staff sailed aboard commercial vessels in the Southern New England SMBT Fishery during routine fishing operations. Baskets were used to sample the catch every time the bag was spilt to bring herring onboard. The baskets were sorted by species and each species was weighed creating a percent composition. The percentages were multiplied by the captains hail weight to create an estimate of weight by species. For example 132 lbs of fish were weighed, 125 lbs (94%) of Atlantic Herring, 5 lbs (4%) of Alewife and 2 lbs (2%) of Whiting, the captains hail amount was 3000 lbs and the final weight estimations were 2841 lbs, 114 lbs and 45 lbs respectively.
Study Fleet staff has sailed on 18 trips, totaling 65 individual efforts, of the SMBT herring fishery (Fig 1). Sampling occurred from December 2011 through February 2013. During the 2011/2012 fishery the majority of fishing effort took place close to shore off the east and south coasts of Rhode Island and the west and south sides of Block Island. During the 2013 season the effort was focused slightly further offshore (Fig 1).
Incidence of river herring bycatch increased from the 2011/2012 SMBT herring season to the 2013 season. Both the average percent alosid and lbs/hr for each tow more than doubled (1.15% to 3.89% and 121.15 lbs/hr to 304.02 lbs/hr) from 2011/2012 to 2013 respectively. The increase in river herring bycatch could be a result of the fishery taking place over a wider area due to the decreased concentration of Atlantic herring in 2013. Though the overall population of river herring is low there is some evidence that river herring runs in Rhode Island have strengthened, thus increasing the likelihood of interaction with fishing gear.