Assessment of the implications of interactions between fur seals and sea lions and the southern rock lobster and gillnet sector of the Southern and Eastern Scalefish and Shark Fishery (SESSF) in South Australia

Project number: 2005-077
Project Status:
Completed
Budget expenditure: $19,999.00
Principal Investigator: Simon D. Goldsworthy
Organisation: SARDI Food Safety and Innovation
Project start/end date: 29 Jun 2005 - 7 Sep 2007
Contact:
FRDC

Need

Provisions of the Commonwealth Environment and Biodiversity Conservation Act, requiring strategic assessment of fisheries against the principles of ESD including the need to monitor, assess and, if necessary, mitigate the interactions of fisheries with protected species (Fletcher et al. 2002).

In both the SA rock lobster and southern shark fisheries, there are considerable, policy and research requirements relating to fishery interactions with fur seals and sea lions that need to be undertaken within the next 2-3 years in order to fulfil recommendations detailed in recent Bycatch Action Plans and ESD Assessments (detailed in B2).

The National Seal Action Plan requires the estimation of sea lion and fur seal bycatch in gillnet, trawl, trap, dropline and longline fisheries and quantification of interactions with fishing equipment.

Assessment for the need for fishery closures to protect sea lions in the Great Australian Bight Marine Park.

Pinnipeds are listed as protected species under the Commonwealth Environment and Biodiversity Conservation Act, and are known to interact with lobster and gillnet fisheries.

Methods for assessing, monitoring and mitigating the interactions of pinnipeds with lobster and gillnet fisheries are needed urgently.

This need is greatest in South Australia, where:
1. the majority of populations of Australian sea lions occur, and where declining populations have been identified, and where
2. Australia’s largest populations of New Zealand fur seals occur, and where
3. a valuable ($80 M) fishery for southern rock lobster (Jasus edwardsii) is located, and
4. where unquantified interactions between pinnipeds and the lobster and southern shark fisheries are known to occur.

The need to assess the interaction of the Australian sea lion with the South Australian lobster and southern shark fishery is particularly pressing, because the Australian sea lion:
(1) is Australia’s only endemic pinniped;
(2) may be more vulnerable to fishery-induced mortality than other species;
(3) is mainly confined to South Australia, with ~80% of pup production occurring in this state; and
(4) has recently been listed as Threatened (Vulnerable Category)under Commonwealth EPBC Act legislation.

Fletcher, W. J., Chesson, J., Sainsbury, K. J., Hundloe, T., Smith, A. D. M., and Whitworth, B. (2002). National ESD reporting Framework for Australian Fisheries: The “How to Guide for Wild Capture Fisheries” FRDC report 2000/145, Canberra, Australia.

Objectives

1. Synthesise and review the PIRSA and AFMA fishery logbooks for the SA Rock Lobster and Commonwealth shark fisheries for reportings of interactions with seals.
2. Undertake a desktop risk assessment of seal-fishery interactions in the SA Rock lobster and Commonwealth shark fisheries, based on distribution of catch and effort in proximity to seal populations.
3. Review the managment responses related to the extent of protected species interactions with similar species and fisheries on a global scale.
4. Develop a proposal for a comprehensive study to assess the level and nature of interactions between seals and the SA Rock Lobster and Commonwealth shark fisheries, including the development of guidelines for measuring the performance of systems for monitoring, assessing and mitigating interactions between the fisheries and seals.

Final report

ISBN: 978-0-7308-5372-5
Author: Simon Goldsworthy
Final Report • 2008-04-14 • 3.46 MB
2005-077-DLD.pdf

Summary

This report provides the most comprehensive appraisal of the risk posed by bycatch to subpopulations of Australian sea lions and New Zealand fur seals, by the SA rock lobster and gillnet sector SESSF fisheries. Further it has identified the research required to ensure that SA rock lobster and the gillnet sector SESSF fisheries are managed according to ESD principles, and that interactions with seals are measured, assessed and mitigated. Adoption of these recommendations will lead to the development, and adoption by industry and management of mitigation options to reduce seal bycatch. This will ensure that outstanding ESD recommendations detailed in fishery ESD assessments and the mitigation of the key threatening process identified in the Australian sea lion Draft Recovery Plan are addressed, leading to the recovery and potential future delisting of the species. 

Keywords: SA rock lobster fishery (SARLF), gillnet sector of the South Eastern Scalefish and Shark fishery (SESSF), Australian sea lion (ASL), New Zealand fur seal (NZFS), bycatch

Related research

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Industry
Environment

Determining the impact of environmental variability on the sustainability, fishery dynamics and economic performance of the West Coast Prawn Trawl Fishery

Project number: 2005-082
Project Status:
Completed
Budget expenditure: $16,000.00
Principal Investigator: Neil A. Carrick
Organisation: Spencer Gulf and West Coast Prawn Association (SGWCPA)
Project start/end date: 13 Apr 2006 - 1 Aug 2006
Contact:
FRDC

Need

The program addresses the three strategic challenges outlined in FRDC’s Research & Development Plan, 2005-10 namely:
• Natural resources sustainability-development of spatially explicit management models for fisheries sustainability and will include temporal (cycles) effects driven by environment.
• People Development-greater understanding of the processes affecting stocks and better management through industry involvement in decision making.
• Community and Consumer support-through education about factors affecting stocks.
The WCPF production has largely declined over the last 4 years and remains at a depressed state. Industry is faced with paying high interest rates on loans and licence fees for research and management. Moreover, Industry pay for costs (additional to licence fees) associated with fishery independent trawl surveys. There is a need to analyse data and demonstrate that the sustainability and profitability of the fishery is undermined by catastrophic downturns in recruitment attributable to environmental variation linked to El Nino Southern Oscillation (ENSO) events. The fishery is a unique case and will be used as a model to demonstrate the catastrophic impact of environmental disturbance on a fishery for application to the Australian government for funding support through the ‘Exceptional Circumstances” programme.

Objectives

1. To assemble andpdate analyses of fishery dependent catch-effort and fishery independent trawl survey data and environmental information relating to the West Coast prawn fishery (WCPF).
2. To determine the impact of environmental variation (ENSO and upwelling events) on the sustainability, fishery dynamics and economic performance of the WCPF.
3. To develop a case model for an application for support provided under the Australian governments Exceptional Circumstances program (EC).

Final report

ISBN: 978-0-646-49682-5
Author: Neil Carrick
Final Report • 2009-03-23
2005-082-DLD.pdf

Summary

The project has provided an understanding of how environmental variation has impacted on WCPF production. Chapter 1 contains the objectives of the study, background and need for the work. Chapter 2 provides a context for understanding of: a) oceanic and climatological processes which are associated with El Nino episodes and cold water upwelling in WCPF waters and b) the potential impact of a cold water environment in reducing larval survival, advective dispersal (larval supply) to nurseries and reduced recruitment to grounds. Chapter 3 details commercial logbook catch, effort and CPUE on temporal and spatial trends in the WCPF. Catch-effort data were reported by financial and calendar year with calendar year being more informative of the dynamic changes in the stock. Historical catch-effort data show that the WCPF fishery has strong cycles in production and CPUE. CPUE fell to the lowest levels in 1978/79, 1992/93 and in 2003/04. However, the recent decline in WCPF production and CPUE was more prolonged than in the past with zero catch in 2006/07 due to the closure of the fishery. The prolonged decline has association with more frequent El Nino episodes.

The WCPF is considered unique for the following reasons: 1) It is based exclusively on the capture of the Western King prawn (Melicertus latisulcatus) for income; 2) Is an oceanic penaeid fishery situated in a region, the Great Australian Bight (GAB), where El Niño events and cold water upwelling have strong effect on local oceanography; and 3) no other established fishery in Australia has shown such catastrophic stock collapse over an extended period (some 6 years from 2002) which has link to El Nino episodes. Chapter 4 uses catch-effort data to derive Leslie depletion estimates which are integrated with fishery independent recruitment estimates in an evaluation of the effects of El Nino and exploitation on recruitment in Chapter 8. A significant project outcome was the development of a prawn size grade database where grade data was joined to catch-effort data for parameter estimates using SQL procedures. Chapter 5 reports on the size composition in catches from 1996-2005 and results show an exponential decline in the abundance of large spawners over this period. The analysis of commercial prawn grade and depletion data does not support the claim that overfishing is the cause of the recent collapse of the fishery.

Chapter 6 uses fishery-independent sampling surveys to show that the most productive ground, Venus Bay, is a key spawning area (highest egg production) and that changes in abundance (and mortality) in 1991/92 were linked to an El Nino event culminating in stock collapse in 1992/93. Chapters 7 and 8 integrate information from previous chapters and provide estimates of fishery-independent biomass density, annual recruitment trends and spawner abundance trends which: 1) demonstrate that the fishery was in a depressed state in 2006; 2) show that recruit abundance decreases with El Nino indices. 

Keywords: Melicertus latisulcatus, stock collapse, GAB, environmental variation, El Nino, upwelling, recruitment, fishery collapse and Exceptional Circumstances Scheme.