1) The ecosystem effects of fishing need to be understood in order to work towards an EBM model for the Spencer Gulf. The South Australian government’s Marine Manager’s Forum has identified Spencer Gulf as the first area in SA for the development of a marine management plan. Better information on impacts of fishing will reduce the reliance of managers on the precautionary principle in developing management plans.
2) The important results from FRDC project 98/225: Prawn fishery by-catch and discards: fates and consequences for a marine ecosystem, are an understanding of the major components of the food chain in the trawled areas of the Gulf and the identification of the major scavenger groups on discarded by-catch. There is a need to obtain data on population impacts in order to develop trophic dynamic models.
3) A prerequisite for energy-flow models is population data outlining life history parameters, growth, migration and immigration and standing stock of, in principle, all the major species.
4) Previous research by this investigator shows that the quantitatively important scavengers on discarded by-catch in the Spencer Gulf prawn fishery are Degens leatherjackets, sealice (non-parasitic highly aggressive isopods and amphiopods), blue crabs, large stingrays and Port Jackson sharks. The effects of discarded by-catch on the population structure of these species need to be understood with the aim of developing an ecosystem model.
5) The impact of fishing on marine ecosystems (target and by-catch) on sharks, skates and rays is a world-wide problem (Stevens et al. 2000). 50% of the global catch is taken as by-catch. The catch of non-target species can have an impact at the population and ecosystem levels, particularly the removal of top predators. Elasmobranchs are at the top of the food chain in the Spencer Gulf and are important by-catch in the prawn fishery. The ecosystem level effects of fishing on the populations of these species are unknown. Discarded by-catch is susceptible to mortality. This mortality, including sub-lethal effects and post discard mortality, needs to be measured in order to predict ecosystem effects.
6) To adopt the principle of ecological sustainability in the prawn fishery, change negative public perceptions of environmental impacts, and improve fishing practices.
7) To enhance the research capacity in environmental research with emphasis on biological resource utilisation.
(Stevens, J.D., Bonfil, R., Dulvy, N.K. & P.A. Walker 2000. The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES J. Mar. Sci. 57: 476-494.)
Project number:
2003-023
Project Status:
Completed
Budget expenditure:
$697,270.00
Principal Investigator:
Ib Svane
Organisation:
SARDI Food Safety and Innovation
Project start/end date:
12 Jul 2003
-
28 Apr 2007
Contact:
FRDC
SPECIES
1. To obtain measurements of the trawling catchability and poplulation parameters of important by-catch and scavenger species particularly including smaller sharks, skates and rays.
2. To determine survival rates of key by-catch species using measures of physiological stress and mortality associated with capture and handling.
3. To determine whether trawling actually attracts or substantially affects the movement of smaller sharks, skates and rays to scavenge on discarded by-catch.
4. To incorporate the results into a marine tropho-dynamic model for sustainable resource utilisation in the Spencer Gulf (EBM).
PROJECT NUMBER
•
2023-155
PROJECT STATUS:
CURRENT
Prawn trawl sea-snake bycatch reduction device - Assessment, refinement, and extension
1. Comprehensively assess the bycatch reduction performance of the Sea-snake TED/BRD including coverage of when, where, and how sea-snake escape, and what other species are likely to benefit the most from its use.
ORGANISATION:
Sea Harvest Fishing Company Pty Ltd
PROJECT NUMBER
•
2023-109
PROJECT STATUS:
CURRENT
Australian Council of Prawn Fishers Industry Partnership Agreement - Environment RD&E Program
1. Australian wild prawn sector is Ecologically, Economically and Socially sustainable through pursuing low impact, fuel efficient and financially viable prawn trawl gear technology
ORGANISATION:
Australian Council of Prawn Fisheries Ltd (ACPF)
PROJECT NUMBER
•
2023-039
PROJECT STATUS:
CURRENT
Assessing the effectiveness of LEDs, T90 cod-end/grid trawl systems and net modifications for reducing bycatch and improving efficiency and selectivity of catches in South Australian prawn fisheries
1. Assess the effectiveness of LEDs in reducing bycatch, while minimizing prawn loss, in the SGPF
ORGANISATION:
Flinders University