Influence of hook type on catch of commercial and bycatch species in an Atlantic tuna fishery
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

For very narrow results

When looking for a specific result

Best used for discovery & interchangable words

Recommended to be used in conjunction with other fields



Document Data
Clear All
Clear All

For additional assistance using the Custom Query please check out our Help Page


Influence of hook type on catch of commercial and bycatch species in an Atlantic tuna fishery

Filetype[PDF-1.54 MB]


  • Journal Title:
    Marine Policy
  • Personal Author:
  • NOAA Program & Office:
  • Description:
    Experimental sets were conducted on a Taiwanese deep set longline fishing vessel operating in the tropical Atlantic Ocean to evaluate the effects of relatively wide circle hooks vs. Japanese tuna hooks with respect to catch rates of both target and incidental species. On circle hooks there were significantly higher catch rates of bigeye tuna (Thunnus obesus), yellowfin tuna (T. albacares), swordfish (Xiphias gladius) and blue sharks (Prionace glauca) as compared to tuna hooks. Significantly higher rates of albacore (T. alalunga) and longbill spearfish (Tetrapterus pfluegeri) were caught on Japanese tuna hooks as compared to circle hooks. Overall, 55 sea turtles were incidentally captured, most (n=47) of which were leatherback turtles (Dermochelys coriacea), and capture rates were similar between hook type. Immediate survival rates (percentage alive) when landed were statistically similar for all major target fish species and sea turtles independent of hook type. Most (64%) sea turtles were hooked on the first and second branchlines closest to the float, which are the shallowest hooks deployed on a longline. Lengths of six retained species were compared between hook types. Of these, swordfish was the only species to show a significant difference in length by hook type, which were significantly larger on circle hooks compared to tuna hooks. Additional incentives to use circle hooks would be the increased catch rate in targeted bigeye tuna over traditional Japanese tuna hooks. This international collaboration was initiated in direct response to regional fisheries management organization recommendations that encourage member countries to conduct experiments aimed to identify means to reduce bycatch in longline fishing gear. Information presented may be useful for managers in developing international fisheries policies that aim to balance increases in commercial fishery revenue and endangered species protection.
  • Keywords:
  • Source:
    Marine Policy, 65, 68-75
  • DOI:
  • ISSN:
  • Format:
  • Publisher:
  • Document Type:
  • Rights Information:
    Accepted Manuscript
  • Compliance:
  • Main Document Checksum:
  • Download URL:
  • File Type:

Supporting Files

  • No Additional Files
More +

You May Also Like

Checkout today's featured content at

Version 3.26.1