Table of Contents

• Dataset Description
  • Methods & Sampling
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Program Information
• Funding

Industry-science partnership investigating the short-term and long-term discard mortality of spiny dogfish using commercial hook gear in the Gulf of Maine.

Co-P.I.'s:
Shelly Tallack (Gulf of Maine Research Institute)
Lara Slifka (Cape Cod Commercial Hook Fishermen's Association)

Final Report

Abstract

The unpopular spiny dogfish, Squalus acanthias, represents a resource which, in recent years, despite its apparent high abundance, is considered vulnerable to overfishing. This vulnerability hinges on its characteristics of slow growth, late maturation (~6 years in males and ~12 years in females), high maximum age (35-40 years) and low natural mortality (M=0.09). One immediate problem faced by fishery managers is that while spiny dogfish are periodically caught in high numbers as bycatch (during both recreational and commercial trips), there is little information regarding the survivability of the discarded dogfish. Two recent studies have addressed dogfish discard survival from trawl gear and gillnet gear; the current study addresses survival from commercial hook gear.

This collaborative project represents a partnership between the Gulf of Maine Research Institute (GMRI), the Cape Cod Commercial Hook Fishermen's Association (CCCHFA) and commercial fishermen working with each organization in Gulf of Maine waters and Southern New England waters, respectively. The primary research objective was to investigate the short-term discard mortality rate of dogfish from different commercial hook gears. Survivability was investigated through caging studies.

A total of 2,418 dogfish were sampled between the two regions; of these 682 were caged by GMRI (45% males and 55% females) and 1,234 were caged by CCCHFA (27% males and 73% females). Dogfish were subject to three gear/handling treatments: 1) snubbed, 2) unsnubbed and 3) control. An overall regional difference in short-term discard mortality was observed; GMRI recorded significantly lower total mortality (7%) than CCCHFA (22%). Regional, averaged findings showed a sex effect with males demonstrating higher mortality (26%) than females (14%). The largest dogfish of each sex demonstrated greater resilience to mortality. Treatment effects were observed with mortality being highest in snubbed fish (23%), then unsnubbed fish (16%) and finally control fish (13%). Gear effects were found with highest mortality resulting from long-line gear (22%) while the different hand gear-related mortality ranged from 8-17%. The relationship between hook removal treatment and hooking severity index (HSI) was significant; severe mouth and jaw injury was most frequent in snubbed fish but was rare in control fish and the overall trend was that mortality increased with increased HSI.

Considerable variation was observed between the GMRI and CCCHFA findings; this variation was likely caused by differences in: water temperature, levels of parasitic infestation (i.e. sand fleas) and possible differences in handling, tanking and caging procedures. This study's long-term discard mortality assessments were aborted for logistical reasons and as such, these findings represent the range of likely short-term discard mortality from hook gears across the region.

The Northeast Consortium encourages and funds cooperative research and monitoring projects in the Gulf of Maine and Georges Bank that have effective, equal partnerships among fishermen, scientists, educators, and marine resource managers.

The Northeast Consortium seeks to fund projects that will be conducted in a responsible manner. Cooperative research projects are designed to minimize any negative impacts to ecosystems or marine organisms, and be consistent with accepted ethical research practices, including the use of animals and human subjects in research, scrutiny of research protocols by an institutional board of review, etc.

At the 2008 Maine Fisheremen's Forum, the Northeast Consortium organized a session on data collection and availability. Participants included several key organizations in the Gulf of Maine area, sharing what data are out there and how you can find them. 

The Northeast Consortium has joined the Gulf of Maine Ocean Data Partnership. The purpose of the GoMODP is to promote and coordinate the sharing, linking, electronic dissemination, and use of data on the Gulf of Maine region.

The Northeast Consortium was created in 1999 to encourage and fund effective, equal partnerships among commercial fishermen, scientists, and other stakeholders to engage in cooperative research and monitoring projects in the Gulf of Maine and Georges Bank. The Northeast Consortium consists of four research institutions (University of New Hampshire, University of Maine, Massachusetts Institute of Technology, and Woods Hole Oceanographic Institution), which are working together to foster this initiative.

The Northeast Consortium administers nearly $5M annually from the National Oceanic and Atmospheric Administration for cooperative research on a broad range of topics including gear selectivity, fish habitat, stock assessments, and socioeconomics. The funding is appropriated to the National Marine Fisheries Service and administered by the University of New Hampshire on behalf of the Northeast Consortium. Funds are distributed through an annual open competition, which is announced via a Request for Proposals (RFP). All projects must involve partnership between commercial fishermen and scientists.

The Northeast Consortium seeks to fund projects that will be conducted in a responsible manner. Cooperative research projects should be designed to minimize any negative impacts to ecosystems or marine organisms, and be consistent with accepted ethical research practices, including the use of animals and human subjects in research, scrutiny of research protocols by an institutional board of review, etc.