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GEARNET Examines Effects of Seal Predation

Aug 21, 2012
Summer 2012

The latest buzz on Cape Cod has centered on the appearance of great white sharks, but another serious threat has arisen for Cape fishermen: increasing rates of seal predation on commercially caught species. 

In 2011, the Georges Bank Fixed Gear Sector approached GEARNET, the Northeast Groundfish Gear Conservation Engineering Network, with a proposal to quantify seal predation and assess its economic impacts. Fishermen hope to avoid seal-related discards and have tested acoustic seal-deterrent pingers; preliminary results suggest that seals quickly become habituated and that pingers are ineffective. Fishermen, still struggling with catch losses from seals, need an alternative solution. 

GMRI intern Julia Knowles, working with GMRI Gear Technologist Steve Eayrs, has begun an assessment of seal impacts based on At-Sea Monitoring and Northeast Fisheries Observer Program trip logs. The study aims to quantify the impact of seal predation as well as identify any coincident factors such as time, location, or gear type. If seal damage rates are higher inshore during the summer and offshore during the fall, for example, this study can provide a template for fishermen to anticipate and minimize seal interactions. 

Examining where and how often predation occurs not only provides GEARNET and sector members with a sense of the scale of the issue: it may lead to more effective solutions. This research may identify issues with documentation of seal predation and lead to more accurate data collection methods as well.

GEARNET is a collaborative network designed to fund gear research ideas generated by New England groundfish fishermen. GEARNET has received funding from NOAA's Cooperative Research Program to launch a second round of gear research projects. Industry members with completed or ongoing projects may submit additional proposals for consideration. Submit project ideas to: or visit for more information and a listing of last year's projects.

For more information, contact Steve Eayrs at