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

Need

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.

Objectives

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.

Final report

Related research

Environment
Environment
Environment
PROJECT NUMBER • 1998-128
PROJECT STATUS:
COMPLETED

Biological data and model development for management of longfin eel fisheries

1. Estimate population parameters required for a management model. These include survival, density, age structure, growth, age and size at maturity and at recruitment to the adult eel fishery. Estimate their variability among individuals in a range of habitats.
ORGANISATION:
Department of Agriculture and Fisheries EcoScience Precinct