Project number: 2010-062
Project Status:
Completed
Budget expenditure: $659,422.00
Principal Investigator: Vic M. Peddemors
Organisation: NSW Department of Primary Industries
Project start/end date: 1 Jan 2012 - 10 Jul 2013
Contact:
FRDC
TAGS
Sustainability
Stock Assessment
Research
Rac Nsw
Management
SPECIES
Dusky Whaler
Bronze Whaler

Need

World-wide, shark fisheries are reputedly unsustainable. The NPOA Sharks and IUCN list over-fishing as a major threat to Australian shark populations. In NSW, the OTLF catches most sharks. Both the FMS and EIS recognise this component as requiring urgent research due to the perceived high risk to targeted whaler sharks resulting from their known low fecundity and resultant susceptibility to over-fishing.

The OTLMAC and NSW SIAC reiterated concern following the rapid expansion of the large shark fishery during the mid-2000s. The impact of this expansion on the so-called ‘historical shark fishers’ was queried.
Recently, an independent review by CSIRO on behalf of DEWHA highlighted the lack of knowledge to effectively manage this fishery. Subsequently, a new overtly precautionary TAC was determined. This reduced TAC has the potential to negatively affect regional socio-economics. Data enabling a viable and sustainable shark fin fishery, while supporting the conditions for EPBC Act WTOs, are urgently required.

Significant investment by I&I NSW is providing data on shark species composition, their biology, fishing gear details, and spatio-temporal catch information. Although these data will substantially contribute to enabling suitable management protocols, I&I NSW fisheries managers have called for more information on:
(1) stock structure and effective population size to enable sustainable TACs to be set; (2) methods to reduce unwanted catch thereby minimizing environmental impact; (3) movements of target species to enable equitable State-wide access to the resource for fishers while providing temporal-spatial management options to improve risk-management of this fishery.

Considering the OTLF catch levels and historical collapse of other fisheries internationally targeting dusky and sandbar sharks, I&I NSW fisheries managers have requested particular focus on these two whaler shark species. This proposal aims to address the management needs through innovative new techniques utilizing linkages with several laboratories, national research programs and management agencies.

Objectives

1. Genetically resolve the effective population size of dusky and sandbar sharks targeted in the OTLF
2. Determine the short-term and distance movements of sandbar and dusky sharks to assist in the development of potential spatial management options like time-area (spatio-temporal) closures
3. Develop a fishing technique that will decrease mortality of unwanted species, particularly threatened and protected species, to minimize environmental impact of the fishery
4. Assess the effectiveness of the I&I NSW shark field ID-guide through ground-truthing on-board shark identification between fishers and observers, plus via genetic testing
5. Evaluate assessment methods and management indicators for the main shark species that may provide a model for future national and/or international data-poor shark fisheries
6. Apply assessment methods and management indicators for data-poor species that may provide a model for future national and/or international data-poor shark fisheries.
7. Provide scientific data-based advice for management to ensure the future sustainability of shark populations.

Final report

ISBN: 978-1-76058-395-8
Author: Victor Peddemors; Will Macbeth; Damian Collins; Andrew Goulstone; Matthew Ives; Jennifer Ovenden; Paul Butcher
Final Report • 2021-04-30 • 3.50 MB
2010-062-DLD.pdf

Summary

New South Wales Department of Primary Industries (NSW DPI) presents new information exploring the shark catch of the NSW Ocean Trap & Line Fishery and developing methods to ensure an accurately reported, sustainable and profitable fishery for large sharks is maintained.
 
A combination of novel genetic techniques, extensive field work, and numerical modelling was undertaken during this FRDC Shark Futures project.
 
This allowed development of an innovative way to bring together genetic and demographic data for estimating population size and modelling sustainable catch levels for target species. Identification of shark species has historically been problematic with many species lumped into similar groups in historical catch logbooks. The new NSW catch logbooks differentiate between shark species caught in commercial fisheries and a corresponding shark identification guide provided to fishers. We assess the effectiveness of this guidebook in providing accurate catch reporting and determine the minimum data required to be collected to enable fisheries managers and compliance officers to effectively regulate a large shark fishery. As management options have often included a trip limit of total allowable catch, we investigated the fate of sharks caught on demersal longlines and model factors affecting their post-release survivorship. This is particularly pertinent for non-selective fishing gear such as demersal longlines which hook species of conservation value and other bycatch as part of their normal fishing operations. Finally, we also assess the levels of metals and metalloids in shark product sold from this fishery to determine whether there could be any negative health implications for human consumers. Excessive levels of mercury and arsenic were detected and suggestions subsequently made on how to ensure product from NSW large shark fisheries are kept within the standards of Food Standards Australia New Zealand.

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