Bycatch characterization in the Pacific halibut fishery: A field test of electronic monitoring technology


A North Pacific Research Board Grant to
     Dr. William Karp, National Marine Fisheries Service
     Dr. Bruce Leaman, International Pacific Halibut Commission
     Ms. Jennifer Cahalan, Pacific States Marine Fisheries Commission




Links


Contact Information

Jennifer Cahalan, PSMFC,
(206) 526-4185
jennifer_cahalan@psmfc.org

Gregg Williams, IPHC,
(206) 552-7687
Gregg@iphc.int

Brian Mason, NMFS
(206) 526-4227
brian.mason@noaa.gov

Acknowledgements
Funding provided by North Pacific Research Board
Research is cooperative with the commercial halibut fleet; vessel participation is voluntary

Photos curtesy of Bill Monheimer, IPHC and NOAA Fisheries Service.

The increasing focus on the ecosystem approach to fisheries management and the need to include all sources of fishing mortality in single species stock assessments heightens the need for accurate and comprehensive catch data from all fisheries. In the waters off Alaska, Pacific halibut (Hippoglossus stenolepis) is harvested by longline in an individual fishing quota (IFQ) fishery. Bycatch rates of non-target species in the Pacific halibut fishery operating off Alaska are largely unknown. The majority of the vessels operating in the halibut longline fishery in Alaska are not currently subject to at-sea harvest monitoring; hence, estimates of bycatch are not based on direct observation of the fishery.

This North Pacific Research Board funded study focused on comparing methods for assessing bycatch in the Pacific halibut longline fishery. This research tested the ability of electronic monitoring (EM) systems to operate in a commercial setting by comparing estimates of bycatch based on video monitoring and standard NOAA Fisheries Service observer sampling. The final report is available here or from the North Pacific Research Board project web site.

Research Objectives:
This study has two main objectives:
1. Estimation of catch and bycatch rates from data collected on commercial longline vessels using several methods
  1. Electronic (video) monitoring
  2. Standard NMFS observer monitoring
  3. Hook-specific documentation (by a second observer) of fish species (Census of Catch)
2. Evaluations of the relative efficiency, cost, and bias of each of the two bycatch estimation methods (EM, NMFS Observers) relative to a known standard (census)

In 2008 we successfully recruited 4 vessels to participate in the study. This resulted in data collected for 13 trips and over 150 monitored longline sets. Fishing occurred in three different IPHC regulatory areas over a four month period. We compared estimates of bycatch (numbers of fish) based on data collected using each of the above methods. Catch estimates and species identifications based on EM data were comparable with those made by on-board observers.


Based on this study, although limited in scope, EM can be an additional tool for catch monitoring in the commercial halibut fishery off Alaska. However, the potential uses of EM need to be determined by the specific monitoring requirements of each management application. EM is not an alternative to observers for the collection of certain biological specimens (e.g., otoliths, scales, etc.) from the catch. With the further development of EM systems and procedures, estimation of bycatch species composition in numbers of fish in the Pacific halibut fishery could be achieved with a high degree of accuracy.