assessment of eastern australian glass eel stocks and associated eel aquaculture

242 Pages·2009·10.24 MB·English

by  Brett Ingram

ASSESSMENT OF EASTERN AUSTRALIAN GLASS
EEL STOCKS AND ASSOCIATED EEL
AQUACULTURE
Edited by
G. J. Gooley and B. A.Ingram
Final Report
FRDC Project No 97/312 (and No. 99/330)
February 2002
Inland
Fisheries
FISHERIES Queensland
RESEARCH & DEAKIN Government
DEVELOPMENT
Department of
CORPORATION Primary Industries
ASSESSMENT OF EASTERN AUSTRALIAN GLASS
EEL STOCKS AND ASSOCIATED EEL
AQUACULTURE

Edited by

G. J. Gooley and B. A. Ingram

Final Report
FRDC Project No 97/312 (and No. 99/330)

February 2002
ISBN 0 7311 5090 2

© The State of Victoria, Department of Natural Resources and Environment, 2002

http://www.nre.vic.gov.au

Copies of this document are available from:

Marine and Freshwater Resources Institute
Private Bag 20
Alexandra. VIC. 3714.
AUSTRALIA.

or

Fisheries Research and Development Corporation
PO Box 222
Deakin West. ACT. 2600
AUSTRALIA

This publication may be of assistance to you but the State of Victoria and its employees do
not guarantee that the publication is without flaw of any kind or is wholly appropriate for your
particular purposes and therefore disclaims all liability for error, loss or other consequence
which may arise from you relying on any information in this publication.
CONTENTS

TABLE OF CONTENTS ............................................................................................................ i

ACKNOWLEDGMENTS .......................................................................................................... ii

NON-TECHNICAL SUMMARY ............................................................................................. iii

1. EEL AQUACULTURE AND THE GLASS EEL FISHERY: SYNOPSIS OF
GLOBAL PRODUCTION AND AUSTRALIAN DEVELOPMENTS .......................... 1
Geoff J. Gooley

2. ASSESSMENT OF EASTERN AUSTRALIAN ANGUILLA AUSTRALIS
AND A. REINHARDTII GLASS EEL STOCKS ............................................................ 13
Lachlan McKinnon, Richard Gasior, Adrian Collins, Bruce Pease and Frances
Ruwald.

3. ADVANCES IN THE WEANING AND REARING OF JUVENILE
AUSTRALIAN SHORTFIN EELS (ANGUILLA AUSTRALIS) .................................... 83
Brett A. Ingram

4. PRELIMINARY EVALUATION OF NUTRITIONAL REQUIREMENTS OF
INTENSIVELY CULTURED AUSTRALIAN SHORTFIN GLASS EELS
AND ELVERS (ANGUILLA AUSTRALIS) .................................................................. 115
Sena S. De Silva and Rasanthi M. Gunasekera

5. PRELIMINARY ASSESSMENT OF THE AQUACULTURE POTENTIAL
OF THE AUSTRALIAN LONGFIN EEL (ANGUILLA REINHARDTII) ................... 137
Clive M. Jones

6. PRELIMINARY ECONOMIC ANALYSIS OF SELECTED AUSTRALIAN
EEL AQUACULTURE SYSTEMS ............................................................................. 183
Geoff Gooley, Will Dalton and Peter Rawlinson

7. OUTCOMES OF FRDC-FUNDED AUSTRALIAN ANGUILLID GLASS
EEL R&D (1997/8-1999/2000) (FRDC PROJECT NO. 97/312 & NO. 99/330) ........ 197
Geoff J. Gooley

APPENDIX I
Best Practice Guidelines for Australian Glass Eel Fishing and Aquaculture
L.J. McKinnon, B.A. Ingram, B. Larkin and R.J. Gasior

APPENDIX II
Staff Employed on the Project

i
ACKNOWLEDGMENTS
The authors wish to gratefully acknowledge the funding support of the Fisheries Research and
Development Corporation and Fisheries Victoria (Victorian Department of Natural Resources
and Environment) for this project. Significant in-kind contributions from Queensland
Department of Primary Industries, NSW Fisheries, Inland Fisheries Service Tasmania and
Deakin University (Victoria) are also gratefully acknowledged.

Further acknowledgments for the specific participants and associated supporters of the
various components of this relatively large project, which was effectively spread across more
than three years, four Australian states, two anguillid species and at least two different
fisheries disciplines, are provided in the respective chapters of this report. The collective
contributions to this project of these people and the actual project team of researchers and
technicians, the latter of whom have mostly contributed to the preparation of this report as
authors of various chapters, are also gratefully acknowledged by the Principal Investigator
and his R&D colleagues at the Marine and Freshwater Resources Institute in Victoria.

ii
NON-TECHNICAL SUMMARY

97/312 ASSESSMENT OF EASTERN AUSTRALIAN GLASS EEL
STOCKS AND ASSOCIATED EEL AQUACULTURE*
* Incorporating FRDC Project 99/330 Validation of Longfin Eel Aquaculture Potential

PRINCIPAL INVESTIGATOR: Geoff Gooley
ADDRESS: Mgr, Aquaculture Program
Marine & Freshwater Resources Institute
Private Bag 20
Alexandra, VIC 3714
Ph. [phone] fax [phone]
Email [email protected]

OBJECTIVES
1. To characterise migrations and assess stocks of glass eels in coastal catchments of
southern Queensland, NSW, Victoria and Tasmania to enable evaluation of the potential
of seedstock supply for Australian eel aquaculture and wild fisheries.
2. To develop pond and tank culture technology for commercial Australian eel production,
with an emphasis on the use of eastern Australian glass eel seedstock.
3. To contribute to the development of eel aquaculture industry development and fisheries
management plans through the provision of relevant information in the form of reports,
publications, seminars, newsletters and workshops.

It should be noted that the specific objectives for the linked FRDC Project 99/330 Validation
of Longfin Eel Aquaculture Potential are detailed in Chapter 5 of this report.

SUMMARY
The world aquaculture production of freshwater Anguillid eels (Anguillidae) currently exceed
an estimated 216,000 tonnes per annum, worth over US$915 million. This production is
predominantly based on the culture of the European eel Anguilla anguilla in Europe and
China, and the Japanese eel, A. japonica in predominantly China, Taiwan and Japan. Most of
the increase in production in China, the major producer, has come about through the
increasing intensification of farming systems and the diversification from A. japonica alone
into A. anguilla as an additional species. Likewise, the increase in European production of A.
anguilla from farms in the Netherlands and Denmark appears to have occurred as a result of
the introduction of more intensive production techniques, including the use of commercially
available recirculating aquaculture systems. In summary, the combined effect of new species
and systems intensification has substantially increased the production and value of the global
eel aquaculture industry over the last decade. By contrast, in Australia, total production is
iii
presently in the order of 5-700 tonnes per annum, worth AUD$4-7.5million, the vast majority
of which comes from wild fishery harvest, and much of which historically comes from stock
enhanced wild fisheries (also referred to by industry as ‘cultured eels’). Further expansion of
the industry is presently constrained by limited application of intensive production techniques
and limited access to local glass eel supplies.
In this context the present study has been initiated to facilitate development of the Australian
eel aquaculture industry, with the specific emphasis on investigations into glass eel resource
identification for two endemic culture species, viz. the Australian shortfin eel A. australis and
the longfin eel A. reinhardtii, and the further development of intensive culture techniques for
these two species. This study builds on a previous FRDC funded project (No. 94/067)
investigating aspects of Australian shortfin glass eel assessment and aquaculture
development.
Global eel market dynamics and associated access for cultured Australian eel products, along
with existing Australian industry structure, operational philosophy and associated state-based
legislative regimes, are also relevant factors in defining production status, but are not
specifically addressed in this project.

The project has been effectively managed as two components, each with a series of specific
strategies designed to address the relevant project objectives. Key research methods
employed during the Project include:

1. Assessment component
• Collate existing information for A. australis and A. reinhardtii glass eels and establish a
long term monitoring database of distribution and catch statistics for eastern Australia.
• Develop indices of relative abundance/catch rates for glass eels within selected
catchments over the full range of the study area and over a three year time frame.
• Validate and further refine a preliminary model for Australian glass eel recruitment which
factors in spatial and temporal variability and includes key environmental gradients at
both the estuarine and oceanic scale along the east Australian coast.
• Investigate and further refine glass eel fishing techniques and equipment, including
options for minimising bycatch and maximising survival of glass eels.
• Investigate genetic discrimination of eastern Australian and New Zealand glass eel stocks
to determine the most appropriate management units.

2. Aquaculture component
• Investigate optimal production parameters and associated husbandry requirements for
short and long-finned glass eels and subsequent developmental stages under both tank and
pond culture conditions where appropriate.
• Undertake a pilot commercial scale grow-out of short and long-finned glass eels under
both tank and pond culture conditions where appropriate.
• Develop nursery phase tank and pond-based culture strategies and technologies
• Undertake a desktop cost-benefit analysis of available commercial aquaculture options,
including a comparison of tank and pond culture options as stand-alone and/or combined
systems.

The project was a collaborative effort incorporating input from state-based fisheries
agencies/research institutions in Queensland, NSW, Victoria and Tasmania, as well as Deakin
University. This Final Report summarises the various investigations for the two key
components undertaken as part of this project. The report is in the form of a book consisting
of discrete chapters each authored by the relevant researchers responsible for each of the
specific project components and/or associated sub-projects. The aquaculture component was
iv
further supplemented by an additional FRDC Project No. 99/330 Validation of longfin eel
aquaculture potential, specifically (as the title implies) to provide additional information on
the suitability and needs of intensive culture techniques for longfin eels. This work was
carried out by the Principal Investigator Dr Clive Jones of the Queensland Department of
Primary Industries, and is included as part of an all inclusive summary (Project No. 97/312
and No. 99/330) for longfin eel aquaculture under Chapter 5 in this report. The genetic work
undertaken in this study is not included in this report due to late stage technical problems with
the samples. This work will however be subsequently reported at a later date in a
supplementary report once the relevant information is finally collated.

In summary, key results and conclusions for the major project components include:
(cid:131) Suitable sites and fishing techniques have been identified and/or further elucidated in the
present study for harvesting of longfin and shortfin glass eels in Victoria (Snowy River)
and Queensland (Albert River), albeit in the absence of any absolute estimate of the total
size of the resource. Quantities of glass eels in the order of 100-200 kg per species per
site are considered reasonable to be harvested in the first instance on an annual basis,
subject to appropriate, site specific and fishery-wide guidelines.
(cid:131) Clearly much of the risk associated with glass eel harvesting in Australia, for whatever
species, needs to be managed within an ESD framework and adopting a ‘precautionary
approach’, as the underpinning principles of formal eel fishery management plans.
(cid:131) Although suitable sites for harvesting of commercial quantities of glass eels at similar
scales have not yet been confirmed in NSW and Tasmania, both species were collected in
the present study at Port Hacking in NSW, and at least shortfin glass eels were taken in
the Prosser River in Tasmania. This suggests therefore that a significant glass eel
resource may be accessible in these areas, if in fact suitable collection sites and/or
associated fishing techniques can be subsequently identified and/or refined.
(cid:131) Glass eel-based seedstock is considered to offer distinct advantages over ‘later stage’ wild
caught juveniles (eg. elvers) for stock enhancement and aquaculture, including the fact
that they are of a single size and age cohort, can be to some extent selected for specific
characteristics (eg. size, development stage), and can be reasonably assured to be disease-
free once contained and acclimated. Financial cost-benefit and environmental
sustainability imperatives will ultimately determine industry preference for the eel
seedstock of choice.
(cid:131) Glass eels of both shortfin and longfin species have proven to be readily adaptable to a
variety of culture system designs, broadly summarised in the present study as semi-
intensive, pond-based systems and intensive, tank-based systems. Although still not
widely practised in Australia, simulative modelling in the present study clearly shows that
the use of glass eel seedstock for semi and fully intensive production of both species can
be quite profitable (as measured by standard financial indicators) under Best Practice
conditions.
(cid:131) As evaluated in the present study, the use of fish roe from species such as carp, Cyprinus
carpio, warehou, Seriolella brama, and mackerel (Scomberomorini and Scombrini –
various species) for initial weaning of Australian anguillid glass eels, appears to offer
great advantages to local producers.
(cid:131) As a result of the present study, species specific diet formulations, which are more
nutritionally complete than presently available commercial alternatives, are now available
to aquafeed companies for shortfin and longfin eels, if and when aquaculture industry
demand in Australia dictates the need.
v
(cid:131) The simulative cost-benefit analysis in this study clearly suggests that either purchasing
acclimated and weaned glass eels and/or larger, pigmented elvers (collected initially as
glass eels) is likely to be cost-effective, and that growing eels out to a larger size (up to
1kg) over a longer growing period (up to 24 months total) is potentially more profitable
than producing smaller fish (up to 300g) over shorter production cycles (up to 15 months).
Additionally, all production scenarios are sensitive to market prices, with farm-gates
prices at less than $15/kg being only marginally profitable at best, and with higher prices
unlikely to be realised for anything other than the larger fish.
(cid:131) Given the likelihood that Australian anguillid species represent single, genetically
panmictic stocks, there is also a need for a degree of coordination of management
arrangements across state boundaries in Australia, and possibly even including New
Zealand in the case of shortfin eels. This places an additional premium on fisheries
managers in the respective state agencies having ready access to more reliable, accurate
and comprehensive life history and fisheries assessment information on Australian eel
resources, to enable them to better understand all aspects of the differing and very
complex life history stages, from marine (oceanic and inshore) through to freshwater.
Furthermore, the extensive range, complex life history, relatively long life span, age at
first maturity/spawning, and associated spatial and temporal variability of recruitment in
glass eels of all species dictates the need for establishment and maintenance of long term
databases (> 10-20 years?) to be at all effective. The outcomes of this project provide the
basis for some of these databases, particularly in relation to CPUE in the Snowy River in
Victoria, which is likely to be a key monitoring site for the Victorian/south-eastern
Australian extent of the shortfin eel distribution.

Future Australian eel aquaculture R&D needs to focus on industry development and
specifically an analysis of the prevailing industry investment climate and associated risks,
market dynamics and legislative constraints. Further, it is necessary to identify key areas of
market failure as opposed to industry failure, and where appropriate to identify R&D
priorities designed to address such failure. It is likely that in the process it will be necessary
to prescribe broad, nationally-based resource management guidelines and to develop a
suitable industry development model upon which state-based sectors may be structurally
reformed if required. Many such tasks are presently being addressed as part of FRDC Project
No. 2000/264 entitled Australian Eel Aquaculture Industry Development Strategy &
Associated Investment Analysis.

This is a one year project, which was undertaken in 2000/01 by the Marine and Freshwater
Resources Institute (Fisheries Victoria, Department of Natural Resources and Environment)
and is presently being written up as a draft Final Report before submission to FRDC and
subsequent publication

KEY WORDS
Australia, Anguilla, glass eels, assessment, aquaculture

vi
1 EEL AQUACULTURE AND THE GLASS EEL FISHERY:
SYNOPSIS OF GLOBAL PRODUCTION AND
AUSTRALIAN DEVELOPMENTS

Geoff J. Gooley
Marine and Freshwater Resources Institute, Private Bag 20, Alexandra, Vic. 3714.

Gooley, G.J. (2002). Eel aquaculture and the glass eel fishery: Synpsis of global production
and Australian developments. In: Assessment of Eastern Australian Glass Eel Stocks and
Associated Eel Aquaculture (ed. G.J. Gooley and B.A. Ingram), pp 1-11. Final Report to
Fisheries Research and Development Corporation (Project No. 97/312 & No. 99/330).
Marine and Freshwater Resources Institute, Alexandra, Victoria, Australia.

CONTENTS
1.1 GLOBAL EEL AQUACULTURE PRODUCTION ............................................................................................. 1
1.2 GLASS EEL FISHERY ................................................................................................................................. 2
1.3 RECENT AUSTRALIAN EEL AQUACULTURE AND GLASS EEL R&D .......................................................... 8
1.4 REFERENCES .......................................................................................................................................... 10

1.1 GLOBAL EEL AQUACULTURE PRODUCTION
The world aquaculture production of freshwater anguillid eels (Anguillidae) currently exceeds
an estimated 216,000 tonnes per annum, worth over US$915 million (FAO 2000a). This
production is predominantly based on the culture of the European eel Anguilla anguilla in
fresh and, to a lesser extent, saline waters in Europe (notably Italy, the Netherlands and
Denmark) and China, and the Japanese eel, A. japonica in freshwaters in predominantly
China, Taiwan and Japan. The bulk of anguillid production comes from Asia, particularly
China, which produces both species, as well as very small quantities of the American eel, A.
rostrata. Eel production in Europe is restricted exclusively to A. anguilla (FAO 2000a)
(Table 1.1).

At least 18 European countries and five Asian countries contribute to the total global eel
aquaculture production according to the most recent FAO data (FAO 2000a). Of these
countries, Chinese eel aquaculture production has increased the most dramatically over the
last decade or so (>170% between 1989-1998), and now accounts for more than 75% of the
total annual world tonnage. In 1996, the farming area in China for eel was reported to be in
the order of 12,700 ha, with annual production of 147,000 tonnes and a value of US$1.2
billion. Approximately 75% of this was exported, mostly to Japan, which represented about
30% of China’s total fisheries exports (Jiaxin 1999). Although the reported trading value for
China in 1996 far exceeds that reported by FAO (2000a) (US$265 million for 1996), it does
indicate that eel aquaculture in China now effectively dominates world production and that
much of this production is dependent on the demand of the Japanese market. For the period
from 1989 to 1996, the average annual amount of farmed eel supplied from all countries into
the Japanese market alone was > 108,000 tonnes (Jiaxin 1999). It is also noted that the recent
1