Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
RESEARCH ARTICLE

Combining in-trawl video with observer coverage improves understanding of protected and vulnerable species by-catch in trawl fisheries

Vanessa F. Jaiteh A C , Simon J. Allen A , Jessica J. Meeuwig B and Neil R. Loneragan A

A Murdoch University Cetacean Research Unit, Centre for Fish, Fisheries and Aquatic Ecosystems Research, School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia.

B Centre for Marine Futures and School of Animal Biology, Oceans Institute, University of Western Australia, Crawley, WA 6009, Australia.

C Corresponding author. Email: v.jaiteh@murdoch.edu.au

Marine and Freshwater Research 65(9) 830-837 http://dx.doi.org/10.1071/MF13130
Submitted: 28 May 2013  Accepted: 10 December 2013   Published: 2 July 2014

Abstract

Assessments of incidental wildlife mortality resulting from fishing rarely account for unobserved by-catch. We assessed by-catch of protected and vulnerable wildlife species in an Australian trawl fishery by comparing in-trawl video footage with data collected by an on-board observer. Data were obtained from 44 commercial trawls with two different by-catch reduction devices (BRDs). Eighty-six individuals from six major taxa (dolphins, sharks, rays, sea snakes, turtles and sygnathids) were documented from video analysis, including the endangered scalloped hammerhead shark (Sphyrna lewini) and the critically endangered green sawfish (Pristis zijsron). On the basis of the 2008–2009 fishing effort of 4149 trawls and scaling from these results, we estimated the annual catch of protected and vulnerable species (± 1 s.e.) at 8109 ± 910 individuals. Only 34% of by-catch was expelled through the BRDs. Independent observer data for the 44 trawls showed that 77% of the landed by-catch from these taxa were dead when discarded. The results indicate that unaccounted by-catch in trawl fisheries can be substantial, and that current methods of recording by-catch on-board vessels are likely to underestimate total fishing mortality. We recommend gear modifications and their validation through dedicated observer coverage, combined with in-trawl video camera deployments to improve current approaches to by-catch mitigation.

Additional keywords: incidental mortality, IUCN status, observer program, Tursiops truncatus.


References

Allen, S., and Loneragan, N. (2010). Reducing dolphin bycatch in the Pilbara Finfish Trawl Fishery. Final report to the Fisheries Research and Development Corporation (FRDC). Murdoch University, Perth.

Altmann, J. (1974). Observational study of behavior: sampling methods. Behaviour 49, 227–266.
Observational study of behavior: sampling methods.CrossRef | 1:STN:280:DyaE2c7mtlWmsQ%3D%3D&md5=0d0f4a02e4983544a92b029791637aacCAS | 4597405PubMed | open url image1

Alverson, D. L., and Hughes, S. E. (1996). Bycatch: from emotion to effective natural resource management. Reviews in Fish Biology and Fisheries 6, 443–462.
Bycatch: from emotion to effective natural resource management.CrossRef | open url image1

Bache, S. J. (2003). Bycatch mitigation tools: selecting fisheries, setting limits, and modifying gear. Ocean and Coastal Management 46, 103–125.
Bycatch mitigation tools: selecting fisheries, setting limits, and modifying gear.CrossRef | open url image1

Baum, J. K., Meeuwig, J. J., and Vincent, A. C. J. (2003a). Bycatch of the seahorse, Hippocampus erectus, in a Gulf of Mexico Shrimp Fishery: implications for conservation. Fishery Bulletin 101, 722–731. open url image1

Baum, J. K., Myers, R. A., Kehler, D. G., Worm, B., Harley, S. J., and Doherty, P. A. (2003b). Collapse and conservation of shark populations in the Northwest Atlantic. Science 299, 389–392.
Collapse and conservation of shark populations in the Northwest Atlantic.CrossRef | 1:CAS:528:DC%2BD3sXjsF2kuw%3D%3D&md5=7bcfc8e0c3132dd16d6700c460382d49CAS | 12532016PubMed | open url image1

Bellido, J. M., Santos, M. B., Pennino, M. G., Valeiras, X., and Pierce, G. J. (2011). Fishery discards and bycatch: solutions for an ecosystem approach to fisheries management? Hydrobiologia 670, 317–333.
Fishery discards and bycatch: solutions for an ecosystem approach to fisheries management?CrossRef | open url image1

Brewer, D., Heales, D., Milton, D., Dell, Q., Fry, G., Venables, B., and Jones, P. (2006). The impact of turtle excluder devices and bycatch reduction devices on diverse tropical marine communities in Australia’s northern prawn trawl fishery. Fisheries Research 81, 176–188.
The impact of turtle excluder devices and bycatch reduction devices on diverse tropical marine communities in Australia’s northern prawn trawl fishery.CrossRef | open url image1

Broadhurst, M. K., Suuronen, P., and Hulme, A. (2006). Estimating collateral mortality from towed fishing gear. Fish and Fisheries 7, 180–218.
Estimating collateral mortality from towed fishing gear.CrossRef | open url image1

Camhi, M., Valenti, S., Fordham, S., Fowler, S., and Gibson, C. (2009). The conservation status of pelagic sharks and rays: report of the IUCN Shark Specialist Group pelagic shark red list workshop. IUCN Species Survival Commission Shark Specialist Group, Newbury, UK.

Campana, S. E., Joyce, W., and Manning, M. J. (2009). Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags. Marine Ecology Progress Series 387, 241–253.
Bycatch and discard mortality in commercially caught blue sharks Prionace glauca assessed using archival satellite pop-up tags.CrossRef | open url image1

Chopin, F. S., and Arimoto, T. (1995). The condition of fish escaping from fishing gears – a review. Fisheries Research 21, 315–327.
The condition of fish escaping from fishing gears – a review.CrossRef | open url image1

Chopin, F., Inoue, Y., and Arimoto, T. (1996). Development of a catch mortality model. Fisheries Research 25, 377–382.
Development of a catch mortality model.CrossRef | open url image1

Cummins, A. (2004). The Marine Stewardship Council: a multi-stakeholder approach to sustainable fishing. Corporate Social Responsibility and Environmental Management 11, 85–94.
The Marine Stewardship Council: a multi-stakeholder approach to sustainable fishing.CrossRef | open url image1

Davis, M. W. (2002). Key principles for understanding fish bycatch discard mortality. Canadian Journal of Fisheries and Aquatic Sciences 59, 1834–1843.
Key principles for understanding fish bycatch discard mortality.CrossRef | open url image1

Dulvy, N. K., Baum, J. K., Clarke, S., Compagno, L. J. V., Cortes, E., Domingo, A., Fordham, S., Fowler, S., Francis, M. P., and Gibson, C. (2008). You can swim but you can’t hide: the global status and conservation of oceanic pelagic sharks and rays. Aquatic Conservation: Marine and Freshwater Ecosystems 18, 459–482.
You can swim but you can’t hide: the global status and conservation of oceanic pelagic sharks and rays.CrossRef | open url image1

Fletcher, W. J., and Santoro, K. (2009). State of the fisheries report 2008/09. WA Department of Fisheries, Perth.

Fletcher, W. J., and Santoro, K. (2010). State of the fisheries and aquatic resources report 2009/10. WA Department of Fisheries, Perth.

Fletcher, W. J., and Santoro, K. (2011). State of the fisheries and aquatic resources report 2010/11. WA Department of Fisheries, Perth.

Fletcher, W. J., and Santoro, K. (2012). Status reports of the fisheries and aquatic resources of Western Australia 2011/12: the state of the fisheries. WA Department of Fisheries, Perth.

Foster, S. J., and Vincent, A. C. J. (2004). Life history and ecology of seahorses: implications for conservation and management. Journal of Fish Biology 65, 1–61.
Life history and ecology of seahorses: implications for conservation and management.CrossRef | open url image1

Hall, S. J., and Mainprize, B. (2004). Towards ecosystem-based fisheries management. Fish and Fisheries 5, 1–20.
Towards ecosystem-based fisheries management.CrossRef | open url image1

Hall, M. A., Alverson, D. L., and Metuzals, K. I. (2000). By-catch: problems and solutions. Marine Pollution Bulletin 41, 204–219.
By-catch: problems and solutions.CrossRef | 1:CAS:528:DC%2BD3MXjtFOl&md5=75b9b7f3bcd0eff7184064dfc6d3695dCAS | open url image1

Heppell, S., Caswell, H., and Crowder, L. (2000). Life histories and elasticity patterns: perturbation analysis for species with minimal demographic data. Ecology 81, 654–665.
Life histories and elasticity patterns: perturbation analysis for species with minimal demographic data.CrossRef | open url image1

Hill, B. J., and Wassenberg, T. J. (1990). Fate of discards from prawn trawlers in Torres Strait. Marine and Freshwater Research 41, 53–64.
Fate of discards from prawn trawlers in Torres Strait.CrossRef | open url image1

Jaiteh, V. F., Allen, S. J., Meeuwig, J. J., and Loneragan, N. R. (2013). Subsurface behavior of bottlenose dolphins (Tursiops truncatus) interacting with fish trawl nets in northwestern Australia: implications for bycatch mitigation. Marine Mammal Science 29, 266–281.
Subsurface behavior of bottlenose dolphins (Tursiops truncatus) interacting with fish trawl nets in northwestern Australia: implications for bycatch mitigation.CrossRef | open url image1

Kaiser, M. J., and Spencer, B. (1995). Survival of by-catch from a beam trawl. Marine Ecology Progress Series 126, 31–38.
Survival of by-catch from a beam trawl.CrossRef | open url image1

Kennelly, S. J. (1995). The issue of bycatch in Australia’s demersal trawl fisheries. Reviews in Fish Biology and Fisheries 5, 213–234.
The issue of bycatch in Australia’s demersal trawl fisheries.CrossRef | open url image1

Lewison, R. L., Crowder, L. B., Read, A. J., and Freeman, S. A. (2004). Understanding impacts of fisheries bycatch on marine megafauna. Trends in Ecology & Evolution 19, 598–604.
Understanding impacts of fisheries bycatch on marine megafauna.CrossRef | open url image1

Lewison, R. L., Soykan, C. U., and Franklin, J. (2009). Mapping the bycatch seascape: multispecies and multi-scale spatial patterns of fisheries bycatch. Ecological Applications 19, 920–930.
Mapping the bycatch seascape: multispecies and multi-scale spatial patterns of fisheries bycatch.CrossRef | 19544734PubMed | open url image1

Mandelman, J. W., and Farrington, M. A. (2007). The estimated short-term discard mortality of a trawled elasmobranch, the spiny dogfish (Squalus acanthias). Fisheries Research 83, 238–245.
The estimated short-term discard mortality of a trawled elasmobranch, the spiny dogfish (Squalus acanthias).CrossRef | open url image1

Newman, S., Wakefield, C., Skepper, C., Marriott, R., Cliff, M., Boddington, D., Mitsopoulos, G., Rome, B., Green, R., and Blazeski, S. (2011). North Coast demersal fisheries status report. In ‘State of the Fisheries and Aquatic Resources Report 2010/11’. (Eds W. J. Fletcher and K. Santoro.) pp. 190–212. WA Department of Fisheries, Perth.

Pascoe, S., and Revill, A. (2004). Costs and benefits of bycatch reduction devices in European brown shrimp trawl fisheries. Environmental and Resource Economics 27, 43–64.
Costs and benefits of bycatch reduction devices in European brown shrimp trawl fisheries.CrossRef | open url image1

Read, A. J. (2008). The looming crisis: interactions between marine mammals and fisheries. Journal of Mammalogy 89, 541–548.
The looming crisis: interactions between marine mammals and fisheries.CrossRef | open url image1

Reeves, R. R., Smith, B. D., Crespo, E. A., and Nortarbartolo di Sciara, G. (2003). ‘Dolphins, Whales, and Porpoises: 2002–2010 Conservation Action Plan for the World’s Cetaceans.’ (IUCN/SSC Cetacean Specialist Group, IUCN: Gland, Switzerland.)

Reeves, R. R., Berggren, P., Crespo, E. A., Gales, N., Northridge, S. P., Nortarbartolo di Sciara , G., Perrin, W. F., Read, A. J., Rogan, E., and Smith, B. D. (2005). ‘Global Priorities for Reduction of Cetacean Bycatch.’ (World Wildlife Fund, Geneva)

Roberts, C. M., and Hawkins, J. P. (1999). Extinction risk in the sea. Trends in Ecology & Evolution 14, 241–246.
Extinction risk in the sea.CrossRef | open url image1

Ross, M. R., and Hokenson, S. R. (1997). Short-term mortality of discarded finfish bycatch in the Gulf of Maine fishery for northern shrimp Pandalus borealis. North American Journal of Fisheries Management 17, 902–909.
Short-term mortality of discarded finfish bycatch in the Gulf of Maine fishery for northern shrimp Pandalus borealis.CrossRef | open url image1

Stephenson, P. C., and Chidlow, J. (2003). Bycatch in the Pilbara trawl fishery. Final Report to Natural Heritage Trust. (WA Department of Fisheries, Perth.)

Stephenson, P. C., and Wells, S. (2006). Evaluation of the effectiveness of reducing dolphin catches with pingers and exclusion grids in the Pilbara trawl fishery. Final report to Fisheries Research and Development Corporation on Project No. 2004/068. Fisheries Research Report No. 173. (WA Department of Fisheries, Perth.)

Stephenson, P. C., Wells, S., and King, J. A. (2008). Evaluation of exclusion grids to reduce the catch of dolphins, turtles, sharks and rays in the Pilbara trawl fishery. DBIF Funded Project. Fisheries Research Report No. 171. (WA Department of Fisheries, Perth.)

Stevens, J. D., Bonfil, R., Dulvy, N. K., and Walker, P. A. (2000). The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES Journal of Marine Science 57, 476.
The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems.CrossRef | open url image1

Stobutzki, I. C., Miller, M. J., Jones, P., and Salini, J. P. (2001). Bycatch diversity and variation in a tropical Australian penaeid fishery; the implications for monitoring. Fisheries Research 53, 283–301.
Bycatch diversity and variation in a tropical Australian penaeid fishery; the implications for monitoring.CrossRef | open url image1

Suuronen, P. (2005). ‘Mortality of fish escaping trawl gears: by Petri Suuronen.’ (FAO: Rome.)

Suuronen, P., Turunen, T., Kiviniemi, M., and Karjalainen, J. (1995). Survival of vendace (Coregonus albula) escaping from a trawl cod end. Canadian Journal of Fisheries and Aquatic Sciences 52, 2527–2533.
Survival of vendace (Coregonus albula) escaping from a trawl cod end.CrossRef | open url image1

Thompson, S. K. (2002). ‘Sampling.’ 2nd edn. (Wiley: New York.)

Ward, T. (2001). Age structures and reproductive patterns of two species of sea snake, Lapemis hardwickii Grey (1836) and Hydrophis elegans (Grey 1842), incidentally captured by prawn trawlers in northern Australia. Marine and Freshwater Research 52, 193–203.
Age structures and reproductive patterns of two species of sea snake, Lapemis hardwickii Grey (1836) and Hydrophis elegans (Grey 1842), incidentally captured by prawn trawlers in northern Australia.CrossRef | open url image1

Wassenberg, T. J., and Hill, B. J. (1990). Partitioning of material discarded from prawn trawlers in Moreton Bay. Marine and Freshwater Research 41, 27–36.
Partitioning of material discarded from prawn trawlers in Moreton Bay.CrossRef | open url image1

Watling, L., and Norse, E. A. (1998). Disturbance of the seabed by mobile fishing gear: a comparison to forest clearcutting. Conservation Biology 12, 1180–1197.
Disturbance of the seabed by mobile fishing gear: a comparison to forest clearcutting.CrossRef | open url image1



Export Citation