Skip to main content
padlock icon - secure page this page is secure

Open Access Catch Rates with Variable Strength Circle Hooks in the Hawaii-Based Tuna Longline Fishery

Download Article:
(PDF 1,521.9 kb)
The hawaii-based deep-set longline fleet targets bigeye tuna [Thunnus obesus (lowe, 1839)] and infrequently takes false killer whales [fkw,Pseudorca crassidens (owen, 1846)] as bycatch. from 2004 to 2008 with 20%–26% observer coverage, nine mortalities of and serious injuries to fkw were documented in the deep-set fishery in the hawaii eeZ, yielding a mean take estimate of 7.3 animals yr–1. weak hook technology can utilize the size disparity between target and other species to promote the release of larger non-target species. four vessels tested the catch efficacy and size selectivity of 15/0 “strong” circle hooks (4.5 mm wire diameter) that straighten at 138 kg of pull in comparison with 15/0 “weak” (4.0 mm) that straighten at 93 kg of pull. vessels alternated hook types throughout the longline gear and maintained a 1:1 ratio of strong and weak hooks. observers monitored a total of 127 sets of 302,738 hooks, and randomization tests were applied to test for significant differences in catch for 22 species. There were no significant catch differences for bigeye tuna; however, there may be limitations to these inferences because trials were not conducted during spring when larger bigeye tuna are available to the fishery. There were no significant differences in mean length of 15 species. observers collected 76 straightened hooks, of which six were control and 70 were weak hooks. There was one observation of a fkw released from a stronger circle hook. overall, there was no statistical reduction in catch rates of bycatch species.
No References for this article.
No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: July 1, 2012

More about this publication?
  • The Bulletin of Marine Science is dedicated to the dissemination of high quality research from the world's oceans. All aspects of marine science are treated by the Bulletin of Marine Science, including papers in marine biology, biological oceanography, fisheries, marine affairs, applied marine physics, marine geology and geophysics, marine and atmospheric chemistry, and meteorology and physical oceanography.
  • Editorial Board
  • Information for Authors
  • Subscribe to this Title
  • Terms & Conditions
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more