PROJECT NUMBER
•
2012-208
PROJECT STATUS:
COMPLETED
ORGANISATION:
University of Tasmania (UTAS)
SPECIES
3 results
Sustainability of small-scale, data-poor commercial fisheries: developing assessments, performance indicators and monitoring strategies for temperate reef species
Project number:
2002-057
Project Status:
Completed
Budget expenditure:
$195,620.00
Principal Investigator:
Jeremy Lyle
Organisation:
University of Tasmania (UTAS)
Project start/end date:
29 Jun 2002
-
30 Oct 2006
Contact:
FRDC
SPECIES
The development of live fish markets in the early 1990s has created a strong demand for temperate reef species, specifically banded morwong and wrasse. Prior to these developments these species had little commercial value, often being used as bait for rock lobster. This demand has resulted in major increases in fishing pressure directed at the reef fish communities and while there has been much work on tropical species, our knowledge of how temperate reef species respond to fishing pressure is comparatively poor.
Although banded morwong and wrasse have vastly different life history characteristics (early life history, reproductive strategies and age and growth), they are basically sedentary, exhibiting population structuring at a small spatial scale. However, related to the general mis-match between the spatial scales of fishery management, fishing operations and fish population structure, there is considerable potential for localised depletion, and hence for serial depletion of the resources.
In Tasmania, steady declines in catch and catch rates have led to concerns that fishing has already significantly impacted banded morwong stocks. In Victoria, a more controlled approach to the development of the fishery has been taken, with an initial three-year developmental phase to be followed by a review to ascertain long-term sustainability.
Although key fishery indicators, catches and catch rates (analysed at state-wide or regional scales) have remained relatively stable for wrasse, there are anecdotal reports of localised depletions from Tasmania. Furthermore, the selective removal of adult male blue-throat wrasse has the potential to impact significantly on egg production even if female spawner biomass is adequate.
There is therefore an urgent need to develop robust stock assessments, appropriate performance indicators and monitoring strategies for these species if they are to be managed sustainably. However, being small-scale fisheries based on sedentary, spatially structured populations, an innovative approach to fishery and biological monitoring and data analyses is required. Since Tasmanian, Victorian and South Australian fisheries share many common characteristics there are considerable benefits from a coordinated approach to this issue. This study will also have broader implications for other small-scale and data poor fisheries.
1. Develop appropriate and meaningful performance indicators for sedentary reef-dwelling species, using banded morwong and wrasse as models.
2. Determine minimum information requirements for the effective stock assessment of these species.
3. Develop appropriate model frameworks for testing the performance indicators developed for these fisheries.
Final report
Assessment of the impacts of hydro-electric dams on eel stocks in Tasmania and an evaluation and assessment of mitigation strategies
Project number:
2000-186
Project Status:
Completed
Budget expenditure:
$282,684.00
Principal Investigator:
Phillip Boxall
Organisation:
University of Tasmania (UTAS)
Project start/end date:
23 May 2001
-
9 Aug 2004
Contact:
FRDC
SPECIES
Stock enhancement strategies can be a cost-effective means of restoring or maintaining fisheries, and have proven essential in catchments with barriers to migration (Knights and White 1998). Regulation of natural river systems has obstructed eel migration in many catchments, and with the implementation of appropriate management tools such as fish passes / ladders and translocation through trapping / netting programs, restoration of stocks can be achieved. Such strategies have not only proven successful in increasing commercial fishery yields, but also contribute to enhanced spawning stocks and increased silver eel escapements.
Hydro electric operations (dams and power generating turbines) reduce the chance of successful emigration of silver eel, especially for larger female eel (Dekker 1999), and, depending on flow and turbine type and number, may represent a major source of mortality to pre-spawning adults (Ritter et al 1997).The design of downstream passage ways and the use of non-generating periods to reduce mortality have been trialled and implemented in New Zealand, the USA and Europe, but have yet to be adopted or investigated in Australia.
The sustainability of the eel resource in Tasmania and of existing (and potentially new) commercial eel fisheries in hydro-impounded catchments will ultimately depend on the implementation of appropriate and effective mitigation strategies (passage and/or translocations) specific to both upstream and downstream migrations.
This proposed program addresses the issue of sustainability by assessing both cause and effect of impacts and various mitigation options. It is envisaged that the results and recommendations arising from this proposed study will underpin the development of an integrated management strategy for managing eel fisheries in hydro-impacted catchments with direct benefits to managers and industry alike. Results from this study could be readily transferred to other States, with coordination and dissemination through the existing Australian and New Zealand Eel Reference Group (ANZERG).
REFERENCES
Dekker, W. 1999. Effects of Transfers and Restocking of Eel. Report of the EIFAC Working Group on Eels - Denmark, September 1999. Pp13-17.
Knights, B. and E. White, 1998. An appraisal of stocking strategies for the European eel, Anguilla anguilla - In Cowx, I.G. (ed): Stocking and Introduction of Fish. Fishing News Books. Pp 121-140.
Ritter, J.A., Stanfield, M. and Peterson, R.H. 1997. The American Eel in Eastern Canada - Stock Status and Management Strategies. Proceedings of Eel Workshop January 13-14 1997, Quebec City, QC. Can. Tech. Report 2196. 174p.
1. To assess the impacts of hydro-electric dams on eel migrations and eel population structure in Tasmania’s lakes and rivers and to assess the impact of past elver restocking practices in hydro-impounded catchments on eel populations within those catchments.
2. To assess the direct impacts of hydro-electric dams and associated operations (turbine intakes and water management practices) on adult ‘silver’ eel survival rates during their downstream spawning migrations
3. To evaluate various management tools (ladders / bypasses and passage
netting / trapping and translocation) to mitigate impacts and provide recommendations for implementation.
4. To review the management of barriers to eel migration, including overseas experience.
