Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-12T12:56:35.741Z Has data issue: false hasContentIssue false
  • English
  • Français

An overview of the hooking mortality of elasmobranchs caught ina swordfish pelagic longline fishery in the Atlantic Ocean

Published online by Cambridge University Press:  21 November 2012

Rui Coelho ,
Joana Fernandez-Carvalho ,
Pedro G. Lino  and
Miguel N. Santos
Rui Coelho*
Affiliation:
Instituto Português do Mar e da Atmosfera, I.P. (IPMA), Avenida 5 de Outubro s/n, 8700-305 Olhão, Portugal Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Campus de Gambelas FCT Ed.7, 8005-170 Faro, Portugal
Joana Fernandez-Carvalho
Affiliation:
Instituto Português do Mar e da Atmosfera, I.P. (IPMA), Avenida 5 de Outubro s/n, 8700-305 Olhão, Portugal
Pedro G. Lino
Affiliation:
Instituto Português do Mar e da Atmosfera, I.P. (IPMA), Avenida 5 de Outubro s/n, 8700-305 Olhão, Portugal
Miguel N. Santos
Affiliation:
Instituto Português do Mar e da Atmosfera, I.P. (IPMA), Avenida 5 de Outubro s/n, 8700-305 Olhão, Portugal
*
a Corresponding author: [email protected]
Get access

Abstract

Hooking (or “at-haulback”) fishing mortality was analysed in elasmobranchs captured byPortuguese longliners targeting swordfish in the Atlantic Ocean. Information was collectedby on-board fishery observers who monitored 834 longline fishing sets between August 2008and December 2011, and recorded information on 36 067 elasmobranch specimens from 21different taxa. The hooking mortality proportions were species-specific, with some specieshaving relatively high percentages of live specimens at time of haulback (e.g., blueshark, crocodile shark, pelagic stingray, manta, devil and eagle rays), while others hadhigher percentages of dead specimens (e.g., smooth hammerhead, silky shark, bigeyethresher). For the most captured species (Prionace glauca, Pseudocarchariaskamoharai, Isurus oxyrinchus and Alopias superciliosus),logistic generalized linear models (GLMs) were carried out to compare the mortality ratesbetween sexes, specimen sizes and the regions of operation of the fleet. The sex-specificproportions of hooking mortality were significantly different for blue and crocodilesharks, with the males of both species having higher proportions of hooking mortality thanthe females. Specimen size was significant for predicting the hooking mortality for blueand shortfin mako sharks: in both cases, the larger specimens had lower odds of dying dueto the fishing process. There were differences in the hooking mortality depending on theregion of operation of the fleet, but those differences were also species-specific. Forblue and crocodile sharks, the hooking mortality was higher in the Equatorial and southernAtlantic areas (when compared to the NE Atlantic region), while the opposite was observedfor the shortfin mako, with lower mortality rates in the NE tropical area compared withthe other regions. The results presented in this paper can be integrated into futureecological risk assessment analysis for pelagic elasmobranchs. Furthermore, the newinformation can be used to evaluate the impact of recent recommendations prohibiting theretention of some vulnerable elasmobranch species.

Keywords

Hooking mortalitypelagic longline fisheriesbycatchdiscardssharksraysAtlantic Ocean
Type
Research Article
Information
Aquatic Living Resources , Volume 25 , Issue 4 , October 2012 , pp. 311 - 319
Copyright
© EDP Sciences, IFREMER, IRD 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Afonso, A.S., Hazin, F.H.V., Carvalho, F., Pacheco, J.C., Hazin, H., Kerstetter, D.W., Murie, D., Burgess, G.H. 2011, Fishing gear modifications to reduce elasmobranch mortality in pelagic and bottom longline fisheries off Northeast Brazil. Fish. Res. 108, 336–343. CrossRefGoogle Scholar
Arrizabalaga, H., Bruyn, P., Diaz, G.A., Murua, H., Chavance, P., Delgado de Molina, A., Gaertner, D., Ariz, J., Ruiz, J., Kell, L.T., 2011, Productivity and susceptibility analysis for species caught in Atlantic tuna fisheries. Aquat. Living Resour. 24, 1–12. CrossRefGoogle Scholar
Buencuerpo, V., Rios, S., Moron, J., 1998, Pelagic sharks associated with the swordfish, Xiphias gladius, fishery in the eastern North Atlantic Ocean and the Strait of Gibraltar. Fish. Bull. 96, 667–685. Google Scholar
Campana, S.E., Joyce, W., Manning, M.J., 2009, Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags. Mar. Ecol. Prog. Ser. 387, 241–253. CrossRefGoogle Scholar
Carruthers, E.H., Schneider, D.C., Neilson, J.D., 2009, Estimating the odds of survival and identifying mitigation opportunities for common bycatch in pelagic longline fisheries. Biol. Conserv. 142, 2620–2630. CrossRefGoogle Scholar
Coelho, R., Santos, M.N., Amorim, S., 2012, Effects of hook and bait on targeted and bycatch fishes in an equatorial Atlantic pelagic longline fishery. Bull. Mar. Sci. 88, 449–467. CrossRefGoogle Scholar
Cortés, E., Arocha, F., Beerkircher, L., Carvalho, F., Domingo, A., Heupel, M., Holtzhausen, H., Santos, M.N., Ribera, M., Simpfendorfer, C., 2010, Ecological risk assessment of pelagic sharks caught in Atlantic pelagic longline fisheries. Aquat. Living Resour. 23, 25–34. CrossRefGoogle Scholar
Diaz, G.A., Serafy, J.E., 2005, Longline-caught blue shark (Prionace glauca) : factors affecting the numbers available. Fish. Bull. 103, 720–724. Google Scholar
Dulvy, N.K., Baum, J.K., Clarke, S., Compagno, L.J.V., Cortés, E., Domingo, A., Fordham, S., Fowler, S., Francis, M.P., Gibson, C., Martinéz, J., Musick, J.A., Soldo, A., Stevens, J.D., Valenti, S., 2008, You can swim but you can’t hide : the global status and conservation of oceanic pelagic sharks and rays. Aquat. Conserv. Mar. Freshw. Ecosyst. 18, 459–482. CrossRefGoogle Scholar
Enever, R., Catchpole, T.L., Ellis, J.R., Grant, A., 2009, The survival of skates (Rajidae) caught by demersal trawlers fishing in UK waters. Fish. Res. 97, 72–76. CrossRefGoogle Scholar
Hastie T., 2011, gam : generalized additive models. R package version 1.04.1. http://CRAN.R-project.org/package=gam.
ICCAT, 2009, Recommendation by ICCAT on the conservation of thresher sharks caught in association with fisheries in the ICCAT convention area. ICCAT Recommendation 2009-07. URL : http://www.iccat.es/Documents/Recs/compendiopdf-e/2009-07-e.pdf.
ICCAT, 2010a, Recommendation by ICCAT on the conservation of oceanic whitetip shark caught in association with fisheries in the ICCAT convention area. ICCAT Recommendation 2010-07. URL : http://www.iccat.es/Documents/Recs/compendiopdf-e/2010-07-e.pdf.
ICCAT, 2010b, Recommendation by ICCAT on hammerhead sharks (family Sphyrnidae) caught in association with fisheries managed by ICCAT. ICCAT Recommendation 2010-08. URL : http://www.iccat.es/Documents/Recs/compendiopdf-e/2010-08-e.pdf.
ICCAT, 2011, Recommendation by ICCAT on the conservation of silky sharks caught in association with ICCAT fisheries ICCAT Recommendation 2011-08.
Mandelman, J.W., Farrington, M.A., 2007, The estimated short-term discard mortality of a trawled elasmobranch, the spiny dogfish (Squalus acanthias). Fish. Res. 83, 238–245. CrossRefGoogle Scholar
Morgan, A., Burgess, G.H., 2007, At-vessel fishing mortality for six species of sharks caught in the northwest Atlantic and Gulf of Mexico. Gulf Carib. Res. 19, 123–129. Google Scholar
Morgan, A., Carlson, J.K., 2010, Capture time, size and hooking mortality of bottom longline-caught sharks. Fish. Res. 101, 32–37. CrossRefGoogle Scholar
Moyes, C.D., Fragoso, N., Musyl, M.K., Brill, R.W., 2006, Predicting postrelease survival in large pelagic fish. Trans. Am. Fish. Soc. 135, 1389–1397. CrossRefGoogle Scholar
Musyl, M.K., Moyes, C.D., Brill, R.W., Fragoso, N.M., 2009, Factors influencing mortality estimates in post-release survival studies. Mar. Ecol. Prog. Ser. 396, 157–159. CrossRefGoogle Scholar
Musyl, M.K., Brill, R.W., Curran, D.S., Fragoso, N.M., McNaughton, L.M., Nielsen, A., Kikkawa, B.S., Moyes, C.D., 2011, Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks in the central Pacific Ocean. Fish. Bull. 109, 341–368. Google Scholar
Petersen, S.L., Honig, M.B., Ryan, P.G., Underhill, L.G., Compagno, L.J.V., 2009, Pelagic shark by-catch in the tuna- and swordfish-directed longline fishery off southern Africa. Afr. J. Mar. Sci. 31, 215–225. CrossRefGoogle Scholar
R Development Core Team, 2011, R : A language and environment for statistical computing. Version 2.13.0. R Foundation for Statistical Computing, Vienna, Austria. http://www.R-project.org.
Rodriguez-Cabello, C., Fernández, A., Olaso, I., Sánchez, F., 2005, Survival of small-spotted catshark (Scyliorhinus canicula) discarded by trawlers in the Cantabrian Sea. J. Mar. Biol. Assoc. UK 85, 1145–1150. CrossRefGoogle Scholar
Smith, S.E., Au, D.W., Show, C., 1998, Intrinsic rebound potentials of 26 species of Pacific sharks. Mar. Freshw. Res. 49, 663–678. CrossRefGoogle Scholar
Stevens, J.D., Bonfil, R., Dulvy, N.K., Walker, P.A., 2000, The effects of fishing on sharks, rays, and chimaeras (Chondrichthyans), and the implications for marine ecosystems. ICES J. Mar. Sci. 57, 476–494. CrossRefGoogle Scholar
Walsh, W.A., Bigelow, K.A., Sender, K.L., 2009, Decreases in shark catches and mortality in the Hawaii-based longline fishery as documented by fishery observers. Mar. Coast. Fish. 1, 270–282. CrossRefGoogle Scholar
Warnes G.R., Bolker B., Lumley T., Johnson R.C., 2011, gmodels : Various R programming tools for model fitting. R package version 2.15.1. http://CRAN.R-project.org/package=gmodels.