Tactical Research Fund: Developing a management framework and harvest strategies for small scale multi-species, multi-method community based fisheries, using the South Australian Lakes and Coorong Fishery as a case study
There are inherent challenges in managing small scale multi-species, multi method fisheries, particularly in a community based fishery context, which require careful consideration in the development of appropriate harvest strategies. While there is a significant degree of targeting involved in multi-species fisheries, the majority of target species will not always be caught during individual gear sets, and the species composition of the catch may be spatially or temporally specific. It can be difficult to ensure that all species caught are fished sustainably (and not only the target species) because species have various life-history characteristics and productivities, and different degrees of susceptibility to the gear. Many species are caught by a variety of gears and it is often difficult to account for all sources of mortality in assessments and the different life stages targeted by particular gear types. The development of harvest strategies for data-poor fisheries presents additional challenges in attempting to reconcile available information and capacity with formal, defensible strategies that achieve the desired objectives for the fishery and fisheries legislation. There is a need for harvest strategies, particularly for community-based fisheries, to be easily understood and accepted by key stakeholders, pragmatic and cost effective.
The LCF is a small scale multi-species, multi-method community based fishery located at the end of the Murray-Darling system and is subject to varying environmental conditions (drought and flooding). The primary target species include Pipi, Yellow-eye Mullet, Golden Perch, Mulloway, Greenback Flounder and Black Bream. A number of other marine, estuarine and freshwater species (native and exotic) are also taken. The fishery contributes to the socio-economic well-being of regional coastal communities in the Lakes and Coorong region through commercial and recreational activity and harbors significant cultural and spiritual significance for the Ngarrindjeri people.
Final report
The commercial Lakes and Coorong Fishery (LCF) operates at the end of the Murray-Darling Basin where the river system meets the Southern Ocean, encompassing a diverse range of freshwater, estuarine and marine habitats and communities. This multi-gear fishery targets a range of species including Pipi (Goolwa cockle - Donax deltoides), Mulloway (Argyrosomus japonicus), Yelloweye Mullet (Aldrichetta forsteri), Black Bream (Acanthopagrus butcheri), Greenback Flounder (Rhombosolea tapirina), Golden Perch (Macquaria ambigua), and Bony Bream (Nematalosa erebi) as well as the introduced fish species European Carp (Cyprinus carpio) and Redfin (Perca fluviatilis).
The outputs of this project will be used to improve the performance of the LCF and will be directly incorporated into the development of harvest strategies developed for finfish species under the new fishery management plan due in 2015. The longer term outcome from this project is that the approach used to develop this management framework can be adapted to other similar fisheries around Australia. Using the capacity of the Australian Fisheries Management Forum, the development of fishery management frameworks and performance indicators will be provided to other jurisdictions to support fishery management improvement in other small-scale, multi-species, multi-method, community-based fisheries.
Keywords: Harvest Strategy, small-scale fisheries, Lakes and Coorong Fishery, data-poor fishery
Assessing the feasibility of an industry-based fishery-independent survey of the SEF
This proposal is part of a strategy co-ordinated by SEFAG and SEF Research Committee aimed at addressing the need for fishery independent survey data.
In order to address this broader need, SEFAG and SEFMAC Research Committee have identified two more immediate needs.
1. The need to build industry support for this initiative is paramount. As identified by SEF Research Committee, SEF industry members have little faith in the use of commercial catch rates as an index of abundance because they are substantially influenced by quota availability, market demands and environmental conditions. The concern that they express is that short term variability due to these factors will be interpreted and acted upon by managers as a change in actual abundance. In other countries where long-term industry-based surveys have been conducted, however, the fishery independent indices have made it possible to remove the influences of quota and market demand and quantify the impact of environmental variability on catch rates. This has made it possible, over time, to standardise survey catch rates for the impact of environmental effects. Exposing members of the SEF community to this international experience should go some way to addressing these concerns and building support.
2. If it is to succeed, there is a need to develop a cost-effective and statistically robust design for a long-term program of industry-based surveys. To build support and move towards implementation it is necessary to develop a survey design. Obviously any survey design needs to be cost-effective and capable of providing statistically robust indices of abundance. With an a agreed survey design members of the SEF community can start considering a concrete proposal for implementation and assessing the costs and benefits of proceeding with implementation.
Final report
Design of a fishery independent longline survey for chondrichthyans in Northern Australia
Catch Per Unit Effort (CPUE) from commercial logbooks is often used as an index of abundance in stock assessments. However, the use of commercial CPUE as an indicator of relative abundance can be problematic as the underlying assumption that commercial catch rates change linearly with abundance is often compromised. Although some factors that are reported in logbooks can be used to standardise CPUE, there are other sources of variation including:
• Modified fishing practices to target or avoid species to suit quota availability, meet market demands, or to comply with management arrangements.
• Differences in selectivity of fishing gear and use of bycatch-reduction devices.
• The combined impacts of multiple management restrictions on a fishery.
For example, gillnet operations in what was once the Northern Territory’s Shark Fishery now almost exclusively target Grey Mackerel. This change in practice has resulted in an index that is losing its relevance in assessing shark species.
Over 140 elasmobranchs are listed on CITES Appendix II, with the likely-hood that more species will be added in the future. Of the 11,082t of shark landed by the fishery since 2000, CITES listed Hammerheads comprise 17.25% of the shark catch. Other sharks caught by the fishery that were recently added to CITES Appendix II at the Nineteenth meeting of the Conference of the Parties Panama City (Panama), 14 – 25 November 2022 include: Grey Reef Shark, Dusky Whaler, Sandbar Shark, Lemon Shark, Whitecheek shark and all other members of the family Carcharhinidae (which include the Blacktip Shark complex that is the main shark species caught by the fishery - 4688t or 42% since 2000). These species will require a positive Non-Detriment Finding (NDF) and CITES export permit in order to be exported following the 12-month delay in implementation (i.e., December 2023). The fishery also catches Threatened, Endangered and Protected Elasmobranchs, some of which are also CITES listed.
Gillnet and longline effort has decreased since 2000 and there is significant latent effort in the fishery. There is a desire to utilise this latent effort, however, the CITES listing of the majority of sharks species caught in the fishery will increase scrutiny from State, Commonwealth and International environmental agencies, as well as NGOs. This heightened scrutiny will provide greater impetus to demonstrate that shark stocks are at sustainable levels and that fishing is being undertaken sustainably.
There is a strong need for independent survey methods to gain a better understanding of the abundance patterns of shark species over time that can contribute to the development of appropriate management of these species that meets environmental, fisheries, and conservation needs.
Surveying Northern Australia using longlining methods would provide a fishery independent estimate of relative abundance for sharks that would improve economic security and public confidence in sustainability. However, to make an informed decision of the feasibility of a survey a full understanding of the scope of work and cost required is needed. There is a need to look at existing long line surveys undertaken worldwide (e.g. in the USA and Bahamas), to understanding the methods undertaken and the time period required to develop accurate abundance estimates.