Hello David, and thanks for your info, and thanks also to the ones with
previous posts on the issue.Actually, i didnt get such
conclusión.Someone asked me about it, but after reading your response I
think it was probably referring not to levels of bycatch, but rather
increased bycatch mortality.
However, as far as i know, fishermen are reluctant to use them as they
claim to reduce fishing eficiency on (some) target species. Nevertheless
, i agree with you, at least they are an approach to the problem.
David Kerstetter escribió:
> Greetings from Florida, J.P.
> As with Mike Pol, I'm curious how you reached your conclusions about
> the use of circle hooks with regards to bycatch. There's actually
> quite a bit of literature available on the use and results of circle
> hooks, ranging from original research (for examples, see such papers
> as Watson et al., 2005 or Kerstetter and Graves, 2006) to reviews
> (including Cooke and Suski, 2004). This body of work with circle
> hooks now covers several commercial and recreational fisheries,
> examining aspects such as catch rates and hooking location. A free
> "Google Scholar" (http://scholar.google.com/) search shows many of
> these papers even have free .pdf versions available online.
> I would also suggest differentiating between catch rates of bycatch
> species and bycatch mortality -- they are very different ideas, and
> the use of circle hooks may affect these two factors differently. For
> example, circle hooks in multiple studies have shown a decrease in the
> catch of pelagic stingrays, a bycatch species in the pelagic longline
> fishery. Circle hook studies with catch rates of sharks have shown
> conflicting results, in part I believe because of the difficulty in
> correctly ascribing catch rates with lost hooks, events that can occur
> when sharks are hooked deeply or at least in such a way that they can
> bite through the monofilament leader and thus release themselves from
> the gear. Catch rates of istiophorid billfishes have shown
> conflicting results in studies with circle hooks in the pelagic
> longline fishery, although their mortality rates are generally lower
> with these hooks at haulback than with J-style hooks. Assessments of
> the post-release mortality associated with capture by different hook
> types is yet another field of work, one generally involving the use of
> electronic tags (e.g., Horodysky and Graves, 2006) or acoustic
> tracking. Please note that I've cited some pelagic fisheries work
> only because it's most familiar to me, but much more literature exists
> on the use of circle hooks with other marine fisheries, such as
> serranid groupers (e.g., Bacheler and Buckel, 2004).
> Circle hooks are not the "silver bullet" answer to bycatch interaction
> and bycatch mortality issues, but then again, there are very rarely
> such solutions for any fisheries problems. In a grossly oversimplying
> sense, circle hooks appear to show a good deal of promise in many
> fisheries for reducing bycatch mortality, especially for such species
> as the istiophorid billfishes, while remaining neutral to the catch
> rates of target species. Not all fishes (or marine organisms, for
> that matter) feed using the same techniques however, which would be
> just one of many factors explaining the variations in results between
> species and fisheries.
> Best regards,
> Dave Kerstetter
> Bacheler, N.M. and J.A. Buckel. 2004. Does hook type influence the
> catch rate, size, and injury of grouper in a North Carolina commercial
> fishery? Fisheries Research 69: 303-311.
> Cooke and Suski. 2004. Are circle hooks an effective tool for
> conserving marine and freshwater recreational catch-and-release
> fisheries? Aquatic Conservation: Marine and Freshwater Ecosystems
> 14(3): 299-326.
> Horodysky, A.Z., and J.E. Graves. 2005.
> of pop-up satellite archival tag technology to estimate postrelease
> survival of white marlin (Tetrapturus albidus) caught on circle and
> straight-shank ("J") hooks in the western North Atlantic recreational
> Fishery Bulletin, 103:84-96.
> Kerstetter, D.W. and J.E. Graves. 2006.
> of size 16/0 circle versus size 9/0 J-style hooks on target and
> non-target species in a pelagic longline
> Fisheries Research 80: 239-250.
> Watson, J.W. et al. 2005.
> Fishing methods to reduce sea turtle mortality associated with pelagic
> Canadian Journal of Fisheries and Aquatic Sciences 62(5): 965-981.
> At 01:48 AM 12/8/2008, Juan Pedro Monteagudo wrote:
>> Hi everyone, im looking for some literature on implementation of
>> circle hooks and estimates on mitigation of bycatch, as it seems they
>> might not be such a good alternative or even being worst at the end.
>> Thanks in advance.
>> JP Monteagudo
>> Juan Pedro Monteagudo González
>> Asesoria Técnica en Pesquerías y Ciencias del Mar
>> Fisheries and Marine Sciences Consultant
>> [log in to unmask]
>> [log in to unmask]
>> +(34) 647844645
> David W. Kerstetter, Ph.D.
> Research Scientist and Adjunct Faculty
> Nova Southeastern University Oceanographic Center
> 8000 North Ocean Drive
> Dania Beach, FL 33004