Shark Depredation and Unwanted Bycatch in Pelagic Longline
Shark Depredation and Unwanted Bycatch in Pelagic Longline
Shark Depredation and Unwanted Bycatch in Pelagic Longline
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
USA Hawaii-based <strong>Pelagic</strong> Longl<strong>in</strong>e Swordfish <strong>and</strong> Tuna Fisheries<br />
A8.11.9. What is the most important factor that affects<br />
shark CPUE - alter<strong>in</strong>g fish<strong>in</strong>g position <strong>in</strong> relation to certa<strong>in</strong><br />
water temperature, topographic features, or oceanographic<br />
features; chang<strong>in</strong>g the time of day or month of sett<strong>in</strong>g or<br />
haul<strong>in</strong>g; chang<strong>in</strong>g the depth of hooks, or a comb<strong>in</strong>ation of<br />
these factors?<br />
Most respondents believe that the shallower their gear, the closer<br />
the fish<strong>in</strong>g gear is to topographic features such as seamounts <strong>and</strong><br />
shelf breaks, <strong>and</strong> proximity to oceanographic fronts are the three<br />
most important variables that will result <strong>in</strong> a high shark catch rate.<br />
A longl<strong>in</strong>e swordfish capta<strong>in</strong> believes that shark abundance will be<br />
higher on the colder side of fronts while three longl<strong>in</strong>e tuna capta<strong>in</strong>s<br />
believe that certa<strong>in</strong> species of sharks will be more abundant on the<br />
warm side of fronts. Time of day, month, <strong>and</strong> year were not considered<br />
to be important factors determ<strong>in</strong><strong>in</strong>g shark capture.<br />
A8.12. Incentives <strong>and</strong> Attitudes on Reduc<strong>in</strong>g <strong>Shark</strong><br />
<strong>Bycatch</strong> <strong>and</strong> <strong>Depredation</strong><br />
In general, both capta<strong>in</strong>s <strong>and</strong> crew <strong>in</strong> the Hawaii pelagic longl<strong>in</strong>e<br />
swordfish <strong>and</strong> tuna fisheries are <strong>in</strong>terested <strong>in</strong> reduc<strong>in</strong>g shark bycatch<br />
<strong>and</strong> depredation as long as the method employed to achieve this does<br />
not also reduce their catch rate of commercially valuable species. The<br />
four most common reasons identified for want<strong>in</strong>g to reduce shark<br />
<strong>in</strong>teractions are to (i) reduce the time required to discard caught<br />
sharks, (ii) reduce the time <strong>and</strong> expense of replac<strong>in</strong>g <strong>and</strong> repair<strong>in</strong>g<br />
lost <strong>and</strong> damaged gear, (iii) reduce lost revenue from damaged target<br />
<strong>and</strong> <strong>in</strong>cidental catch, <strong>and</strong> (iv) reduce the risk of <strong>in</strong>jur<strong>in</strong>g crew from<br />
be<strong>in</strong>g hit by weighted swivels when branch l<strong>in</strong>e break dur<strong>in</strong>g haul<strong>in</strong>g.<br />
Most (two thirds) of respondents stated that they wish to reduce<br />
catch rates of sharks <strong>in</strong> order to reduce the loss of revenue, where<br />
the capture of every shark is one less hook available to catch a target<br />
species. A few respondents clarified that that they want to avoid<br />
catch<strong>in</strong>g sharks because most shark species have no economic value<br />
<strong>and</strong> the two species that can be sold are worth relatively very little.<br />
Only one respondent believes, <strong>in</strong> the absence of restrictions on f<strong>in</strong>n<strong>in</strong>g<br />
sharks, that fish<strong>in</strong>g mortality would result <strong>in</strong> the decl<strong>in</strong>e of shark<br />
populations or that overfish<strong>in</strong>g would occur.<br />
Most (75%) of the respondents stated that their general feel<strong>in</strong>gs about<br />
sharks are that they are a ‘nuisance’ <strong>and</strong> that they wish they could<br />
avoid them. Many respondents see shark depredation, requir<strong>in</strong>g<br />
time to remove sharks from hooks, damag<strong>in</strong>g <strong>and</strong> los<strong>in</strong>g gear, <strong>and</strong><br />
damag<strong>in</strong>g <strong>and</strong> los<strong>in</strong>g caught fish, as an expected <strong>and</strong> unavoidable<br />
part of longl<strong>in</strong>e fish<strong>in</strong>g. A few respondents believe that sharks are<br />
more than just a nuisance, as shark <strong>in</strong>teractions reduce the viability of<br />
their livelihood. This is generally consistent with the results reported<br />
by McCoy <strong>and</strong> Ishihara (1999). Two fishers <strong>in</strong>dicated that they see<br />
sharks as an apex predator at the top of the mar<strong>in</strong>e food cha<strong>in</strong>, <strong>and</strong><br />
as such, sharks play an important role <strong>in</strong> ma<strong>in</strong>ta<strong>in</strong><strong>in</strong>g the natural<br />
function<strong>in</strong>g of the ocean ecosystem. One respondent sees sharks as<br />
a renewable natural resource, which should be managed for optimal<br />
yield just like other commercial mar<strong>in</strong>e fish, <strong>and</strong> that fishers should<br />
be able to f<strong>in</strong> them under a susta<strong>in</strong>able management regime.<br />
A8.13. References<br />
Boggs, C. 1992. Depth, capture time, <strong>and</strong> hooked longevity of longl<strong>in</strong>ecaught<br />
pelagic fish: Tim<strong>in</strong>g bites of fish with chips. Fishery Bullet<strong>in</strong> 90(4):<br />
642-658.<br />
Bolten, A., Bjorndal, K., 2002. Experiment to Evaluate Gear Modification<br />
on Rates of Sea Turtle <strong>Bycatch</strong> <strong>in</strong> the Swordfish Longl<strong>in</strong>e Fishery <strong>in</strong> the<br />
Azores. F<strong>in</strong>al Project Report submitted to the U.S. National Mar<strong>in</strong>e<br />
Fisheries Service. Archie Carr Center for Sea Turtle Research, University<br />
of Florida, Ga<strong>in</strong>esville, Florida, USA.<br />
Brothers, N., E. Gilman. 2006. Technical Assistance for Hawaii <strong>Pelagic</strong><br />
Longl<strong>in</strong>e Vessels to Change Deck Design <strong>and</strong> Fish<strong>in</strong>g Practices to Side Set.<br />
Hawaii Longl<strong>in</strong>e Association, U.S. NOAA Fisheries Pacific Isl<strong>and</strong>s Fisheries<br />
Science Center <strong>and</strong> Pacific Isl<strong>and</strong>s Regional Office, <strong>and</strong> Western Pacific<br />
Regional Fishery Management Council: Honolulu, Hawaii.<br />
Clemens, A. 2006. Annual Report on Seabird Interactions <strong>and</strong> Mitigation<br />
Efforts <strong>in</strong> the Hawaii Longl<strong>in</strong>e Fishery for Calendar Year 2005.<br />
Adm<strong>in</strong>istrative Report AR-PIR-04-06. U.S. National Mar<strong>in</strong>e Fisheries<br />
Service, Pacific Isl<strong>and</strong>s Regional Office, Honolulu, HI, USA.<br />
Gilman, E., D. Kobayashi, T. Swenarton, P. Dalzell, I. K<strong>in</strong>an, N. Brothers.<br />
2006a. Efficacy <strong>and</strong> Commercial Viability of Regulations Designed to<br />
Reduce Sea Turtle Interactions <strong>in</strong> the Hawaii-Based Longl<strong>in</strong>e Swordfish<br />
Fishery. Western Pacific Regional Fishery Management Council, Honolulu,<br />
HI, USA. ISBN 1-934061-02-6.<br />
Gilman, E, Zollett, E., Beverly, S., Nakano, H., Shiode, D., Davis, K., Dalzell,<br />
P., K<strong>in</strong>an, I., 2006b. Reduc<strong>in</strong>g sea turtle bycatch <strong>in</strong> pelagic longl<strong>in</strong>e gear.<br />
Fish <strong>and</strong> Fisheries 7(1): 2-23.<br />
Hamilton, M., R. Curtis, M. Travis. 1996. Cost-earn<strong>in</strong>gs Study of the Hawaiibased<br />
Domestic Longl<strong>in</strong>e Fleet. JIMAR Contribution 96-300. Jo<strong>in</strong>t Institute<br />
for Mar<strong>in</strong>e <strong>and</strong> Atmospheric Research, Honolulu, Hawaii, USA, 59 pp.<br />
Ito, R., Machado, W. 2001. Annual Report of the Hawaii-based Longl<strong>in</strong>e<br />
Fishery for 2000. U.S. National Mar<strong>in</strong>e Fisheries Service Southwest<br />
Fisheries Science Center, Honolulu Adm<strong>in</strong>istrative Report H-01-07,<br />
Honolulu, HI, USA.<br />
Ito, R., Machado, W. 1999. Annual Report of the Hawaii-based Longl<strong>in</strong>e<br />
Fishery for 1998. U.S. National Mar<strong>in</strong>e Fisheries Service Southwest<br />
Fisheries Science Center, Honolulu Adm<strong>in</strong>istrative Report H-99-06,<br />
Honolulu, HI, USA.<br />
McCoy, M., H. Ishihara. 1999. The Socioeconomic Importance of <strong>Shark</strong>s <strong>in</strong><br />
the U.S. Flag Areas of the Western <strong>and</strong> Central Pacific. Gillett, Preston<br />
<strong>and</strong> Associates, Inc., Honolulu, Hawaii, USA, <strong>and</strong> U.S. National Mar<strong>in</strong>e<br />
Fisheries Service Southwest Region Adm<strong>in</strong>istrative Report AR-SWR-00-<br />
01, La Jolla, CA, USA. 117 pp.<br />
Pacific Ocean Producers. 2005. Pacific Ocean Producers Commercial Fish<strong>in</strong>g<br />
<strong>and</strong> Mar<strong>in</strong>e Supplies for the Asia-Pacific Region Catalog 2004-2005. Pacific<br />
Ocean Producers, Honolulu, Hawaii, USA.<br />
U.S. National Mar<strong>in</strong>e Fisheries Service. 2005b. 2005 Report to Congress<br />
Pursuant to the <strong>Shark</strong> F<strong>in</strong>n<strong>in</strong>g Prohibition Act of 2000 (Public Law 106-557).<br />
U.S. National Oceanic <strong>and</strong> Atmospheric Adm<strong>in</strong>istration, U.S. Department<br />
of Commerce, Wash<strong>in</strong>gton, D.C. 52 pp.<br />
131