Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
Shopping Cart: ( empty )
You are here: Home > Journals > MF > MF05190
RESEARCH ARTICLE
Contents Vol 57(4)

Validating ecological risk assessments for fisheries: assessing the impacts of turtle excluder devices on elasmobranch bycatch populations in an Australian trawl fishery

Shane P. Griffiths A C , David T. Brewer A , Don S. Heales A , David A. Milton A and Ilona C. Stobutzki B
+ Author Affiliations
- Author Affiliations

A CSIRO Marine and Atmospheric Research, PO Box 120, Cleveland, Qld 4163, Australia.

B Bureau of Rural Sciences, GPO Box 858, Canberra ACT 2601, Australia.

C Corresponding author. Email: shane.griffiths@csiro.au

Marine and Freshwater Research 57(4) 395-401 https://doi.org/10.1071/MF05190
Submitted: 21 September 2005  Accepted: 6 April 2006   Published: 14 June 2006

Abstract

Demonstrating ecological sustainability is a challenge for fisheries worldwide, and few methods can quantify fishing impacts on diverse, low value or rare species. The current study employed a widely used ecological risk assessment method and incorporated new data to assess the change in sustainability of species following the introduction of Turtle Excluder Devices (TEDs) in Australia’s Northern Prawn Fishery (NPF). Population recovery ranks changed for 19 of the 56 elasmobranch species after the introduction of TEDs, with nine species showing an increase in sustainability. Unexpectedly, ten species showed a decrease in sustainability. This was due to TEDs successfully excluding large animals from the catch, resulting in a lower mean length at capture, which reduced the recovery ranks for two criteria relying on length data. This falsely indicates that TEDs increase the impact on pre-breeding animals, thus reducing the recovery potential of these species. The results demonstrate that existing attribute-based risk assessment methods may be inadequate for reflecting even the most obvious changes in fishing impacts on bycatch species. Industry and management can benefit greatly from an approach that more accurately estimates absolute risk. The development and requirements of a new quantitative risk assessment method to be developed for the NPF, and applicable to fisheries worldwide, are discussed.

Extra keywords: extinction, fisheries management, prawn, rays, sharks, sustainability, tropical.


Acknowledgments

We thank Alistair Hobday, Steve Blaber and Richard Pillans of CSIRO Marine and Atmospheric Research for critically evaluating drafts of this manuscript. Preparation of this manuscript was funded by the Australian Fisheries Research and Development Corporation (FRDC) (Project no. 2002/035) and utilised data collected in two other FRDC funded projects (96/357 and 2000/173).


References

Andrew, N. L. , and Pepperell, J. G. (1992). The by-catch of shrimp trawl fisheries. Oceanography and Marine Biology: An Annual Review 30, 527–565.
Aslin H. J., and Byron I. G. (2003). ‘Community Perceptions of Fishing: Implications for Industry Image, Marketing and Sustainability.’ (Fisheries Research and Development Corporation, and the Bureau of Rural Sciences, Canberra.)

Baum, J. K. , Myers, R. A. , Kehler, D. G. , Worm, B. , Harley, S. J. , and Doherty, P. A. (2003). Collapse and conservation of shark populations in the Northwest Atlantic. Science 299, 389–392.
| Crossref | GoogleScholarGoogle Scholar | PubMed | Brewer D. T., Heales D. S., Eayrs S. J., Taylor B. R., Day G., et al. (2004). Assessment and improvement of TEDs and BRDs in the NPF: a co-operative approach by fishers, scientists, fisheries technologists, economists and conservationists. Final Report on FRDC Project 2000/173, CSIRO Cleveland.

Cheung W. W. L., Pitcher T. J., and Pauly D. (2004). A fuzzy logic expert system to estimate intrinsic extinction vulnerabilities of marine fishes to fishing. In ‘Seamounts: Biodiversity and Fisheries’. (Eds T. Morato and D. Pauly.) pp. 33–50. Fisheries Centre Research Reports 12(5).

Dulvy, N. K. , and Reynolds, J. D. (2002). Predicting extinction vulnerability in skates. Conservation Biology 16, 440–450.
| Crossref | GoogleScholarGoogle Scholar | Environment Australia (2002). ‘Assessment of the Western Australia Shark Bay Prawn Trawl Fishery.’ (Environment Australia: Canberra, Australia.)

FAO Fisheries Department (FAO) (2003). The ecosystem approach to fisheries. FAO Technical Guidelines for Responsible Fisheries. No. 4, Suppl. 2. FAO, Rome.

Gribble N., Whybird O., Williams L., and Garrett R. (2004). Fishery assessment update 1989–2003: Queensland East Coast shark. Report QI 04070. Queensland Department of Primary Industries, Brisbane.

Hall, M. A. (1996). On bycatches. Reviews in Fish Biology and Fisheries 6, 319–352.
| Crossref | GoogleScholarGoogle Scholar | Last P. R., and Stevens J. D. (1994). ‘Sharks and Rays of Australia.’ (CSIRO Publishing: Melbourne.)

Otway, N. M. , Bradshaw, C. J. A. , and Harcourt, R. G. (2004). Estimating the rate of quasi-extinction of the Australian grey nurse shark (Carcharias taurus) population using deterministic age- and stage-classified models. Biological Conservation 119, 341–350.
| Crossref | GoogleScholarGoogle Scholar | Prince J. D. (2002). Gauntlet fisheries for elasmobranchs – the secret of sustainable shark fisheries. Northwest Atlantic Fisheries Organization (NAFO) SCR Document 02/139, Serial No. N4761. Available online at: http://journal.nafo.int/35/prince/29-prince.html [verified May 2006].

Queensland Department of Primary Industries (QDPI) (2004). Review of the sustainability of fishing effort in the Queensland East Coast Trawl Fishery. Discussion paper. Queensland Department of Primary Industries, Brisbane.

Roberts, C. M. , and Hawkins, J. P. (1999). Extinction risk in the sea. Trends in Environment and Ecology 14, 241–246.
Saila S. B. (1983). Importance and assessment of discards in commercial fisheries. FAO Fisheries Circular C765. Food and Agriculture Organization, Rome.

Stevens J. D. (1999). Variable resilience to fishing pressure in two sharks: the significance of different ecological and life history parameters. In ‘American Fisheries Society Symposium 23: Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals’. pp. 11–15. (Ed. J. A. Musick.) (American Fisheries Society: Bethesda, MD.)

Stobutzki, I. C. , Miller, M. J. , Jones, P. , and Salini, J. P. (2001a). Bycatch diversity and variation in a tropical Australian penaeid fishery; the implications for monitoring. Fisheries Research 53, 283–301.
| Crossref | GoogleScholarGoogle Scholar | Zhou S., Griffiths S., Brewer D., Heales D., and Miller M. (2005). A new approach to assess the impact of the Northern Prawn Fishery on the sustainability of bycatch. Oral presentation at ‘The Australian Society for Fish Biology Workshop: Monitoring Fish Stocks and Aquatic Environments, 11–12 July 2005, Darwin, Australia’.