77 results

Development of discard-reducing gears and practices in the estuarine prawn and fish haul fisheries of NSW

Project number: 1997-207
Project Status:
Completed
Budget expenditure: $546,034.00
Principal Investigator: Charles A. Gray
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 22 Jun 1997 - 13 Aug 2002
Contact:
FRDC

Need

Whilst public consternation may be sufficient reason for fisheries managers and scientists to seek solutions to this issue, there are also many biological and economic reasons for doing so. Firstly, there is a clear need to determine the real (not just perceived) level of the problem and how it varies in space and time and among particular fishing methods. If the anecdotal reports of large quantities of juvenile fish being discarded prove correct (addressed in the first stage of the proposed project), and if we can ameliorate such discarding (addressed in the second stage), there would be obvious large and long-term benefits to all interacting recreational and commercial fisheries targetting these species. Further, reducing discards from prawn and fish hauling will improve the efficiencies of these operations and could improve the quality (and even the quantity) of the product - especially in the case of prawn hauling.

The consequences of not completing this study could be substantial. It is possible that in the absence of information, a ban may be inevitable.

Objectives

1. To identify and quantify the by-catch, discards and landed catches from prawn and fish hauling at a variety of locations throughout NSW using a stratified, randomized observer-based survey
these data will be used to determine key gears, methods, areas and times of discarding that will be addressed in Objective 2.
2. To develop, test and implement modifications to current hauling gears and fishing practices that will decrease the identified problematic discards.

Effects of Trawling Subprogram: dynamics of large sessile seabed fauna important for structural fisheries habitat and biodiversity of marine ecosystems, and use of these habitats by key finfish species

Project number: 1997-205
Project Status:
Completed
Budget expenditure: $596,507.00
Principal Investigator: Roland C. Pitcher
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 22 Jun 1997 - 10 Dec 2004
Contact:
FRDC

Need

Predicting the response of megabenthos to the establishment of refuge/replenishment areas and acquiring an understanding of the ecological interactions between trawled and refuge areas are both essential steps in the effective design of refuges for fisheries habitat and the stocks they support. They are also necessary for the development of alternative fishing strategies that have less impact on habitat. To achieve these goals, it will be necessary first to obtain information on the recovery rates of habitat and then the processes which link trawled areas and refuges.

We propose to investigate the population dynamics (recruitment, growth, mortality, reproduction) of structurally dominant megabenthos habitat organisms and document the relationship between benthic habitat and ecological usage by important commercial finfish species. These issues — habitat dynamics and processes — have also been identified at FRDC workshops as high priority areas for future research. Also identified as high priority, especially by managers of tropical finfishes, is the need for finfish resource monitoring. To this end, we also propose to examine environmentally-friendly, fishery-independent techniques for measuring finfish abundance, including remote (baited) video stations and acoustics. Documentation of fish-megabenthos associations is the first step toward mapping the spatial distribution of snapper and emperor grounds on the basis of key habitat proxies, a process now underway in the development of an Interim Marine and Coastal Regionalisation of Australia.

Alternative fishing strategies which have less impact on habitat and lead to increased productivity among commercial species will, by preserving critical habitat in refuges, in turn help reduce conflict between commercial extractive activities and conservation. It will also improve the public perception of trawling. Two possible alternative strategies include: changing from fish-trawl to non-trawl methods; and changing trawling strategies to corridor trawling, in order to allow former trawling grounds to recover and resume their role as fisheries habitat supplying stock to the trawl corridors, whilst maintaining or even enhancing catch rates. In either case, the recovery time frames for the seabed habitat — and hence fisheries resources — are important, because they will influence the economic feasibility of switching to alternative fishing strategies.

The results of this study will become increasingly important as the requirement for ecologically sustainable fisheries management is implemented in trawl fisheries from the temperate zone to the tropics. The lessons learned from this study in the form of knowledge of habitat dynamics, and methods for monitoring habitats and commercial stocks will contribute to a rational balance between ecologically sustainable fishing, biodiversity and conservation when ESD related management changes are implemented in those Australian fisheries dependent on seabed habitat.

Objectives

1. To determine the dynamics (recruitment, growth, mortality, and reproduction) of structurally dominant large seabed habitat organisms (ie. megabenthos = sponges, gorgonians, and alcyonarians and corals etc) important for demersal fisheries habitat and biodiversity of the seabed environment, in a tropical region (ie. GBR).
2. To model the dynamics of seabed habitat and predict the potential of trawled grounds to recover and resume their role as prime fisheries habitat.
3. To document the ecological usage of living epibenthic habitat by key commercial finfish species, in terms of species micro-distribution, shelter requirements, and food chain links.
4. To assess three fishery-independent and "environmentally-friendly" techniques for surveying tropical finfish resource abundance in inter-reefal areas, including fish-traps, remote (baited) video stations and quantitative acoustics.

Final report

ISBN: 1-876-996-77-3
Author: Roland Pitcher

Fish in the shallows of NSW south coast estuaries: variability and diversity of fish communities and the development of biological indicators for sustainability and biodiversity

Project number: 1997-204
Project Status:
Completed
Budget expenditure: $280,358.00
Principal Investigator: Ron J. West
Organisation: University of Wollongong
Project start/end date: 20 Jul 1997 - 31 May 2001
Contact:
FRDC

Need

Major structural changes are occurring in several natural resource industries as the
principles of Ecological Sustainable Development (ESD), Biodiversity Conservation and
National Competition Policy are implemented. These principles are beginning to have a
significant and fundamental impact on natural resource management, at all levels of
Government and in several primary industry areas, such as forestry, agriculture and the
water industry.

The forestry industry, which bears closest parallels with the fishing industry, has
been in the forefront of these policy changes. In NSW forests: implementation of
Biodiversity Conservation principles has led to the reservation of areas traditionally
harvested by industry; implementation of ESD principles has led to the need to prepare
forestry management plans, incorporating indicators of sustainability; and, National
Competition Policies have led to the imminent corporatisation of the NSW forestry
management agency and restriction of its activities to commercial harvesting (as
opposed to other forestry management activities which will be carried out by other
departments and local community management groups).

A major problem in reforming NSW forestry has been the lack of useful forestry data
relating to biodiversity and overall sustainability (eg. faunal components of forests).
This resulted from management agencies not giving priority to collecting data on
biodiversity and has led to somewhat arbitrary decision making and eventual
confrontation. A parallel situation now exists in fisheries where, in general, very
little data has been collected on diversity of fish communities in the vast majority of
areas that are presently being fished.

In NSW, estuary management is the responsibility of many players, such as Catchment
Management Committees, River Trusts, the Department of Land and Water Conservation
(DLWC), National Parks and Wildlife Service (NPWS), as well as NSW Fisheries. For
example: the majority of estuary restoration projects in NSW are carried out by Local
Councils and Catchment Committees; DLWC is implementing "State of the Catchment"
reporting; and, "new" players, such as DLWC and NPWS, are beginning to impose
"external" constraints on fishing activities, with the objective of conserving
biodiversity. Yet very little data exist on variability and diversity of estuarine fish
communities in NSW.

While a number of agencies and groups have a role to play in estuary management,
none are likely to fund a major fisheries project at this stage. This proposed project
is a large-scale fisheries research project, relating directly to fisheries and the health of
fish communities. Every opportunity to involve other external collaborators in this project
will be explored, however only small-scale funding is likely to be achieved, leading to
a fragmented approach to this important collection of data. For example, the applicant has
already been successful in obtaining $5,000 from the Illawarra Catchment Management
Committee (ICMC) with a $10,000 extension of the project from FishCare, but none of the
sampling sites chosen by the ICMC are in areas fished extensively.

During the course of the project, the applicant will be in contact with all the relevant
agencies, such as NSW Fisheries, NSW Dept. Land and WaterConservation, NSW
National Parks and Wildlife, Local Councils and catchment groups, to ensure full
consultation takes place and that maximum collaboration is obtained.

The information to be collected during the course of this proposed FRDC project
is likely to be used widely in various management plans and reports prepared by both
community groups and Government, including:

* fisheries management plans,
* estuary management plans,
* catchment management plans, and,
* state of the environment reporting.

The inclusion of fisheries information in these reporting mechanisms would: raise the
profile of fisheries issues; encourage such data to become an established part of the
estuary health indicators; and, in so doing, help in future funding of on-going "monitoring"
programs, based on this research project. All of the above reports will be vital to the future
of the fishing industry in NSW. The NSW Fishing Industry Research Advisory Committee
(NSW FIRAC) has acknowledged the importance of the type of data collected from
this proposed project and, as a result, considered it to be amongst their highest priorities
for FRDC funding.

This project will provide data on shallow water fish communities in a wide range of estuaries
throughout southern NSW and will examine the usefulness of these data as indicators of
sustainability and biodiversity. Data on these shallow water fish communities are
comparatively easy to collect, but offer several advantages over other possible
sampling methods (see Appendix 2). The collection of environmental data at each
of the sampling sites will also provide useful information in itself, as well as important data
for the interpretation of changes in the shallow water fish populations.

Objectives

1. To examine variability in the diversity and abundance of fishes within and between selected estuaries, coastal lakes and lagoons in southern NSW, including fished and non-fished areas.
2. To provide the first set of comparative data for the south coast region of NSW on the recruitment intensity for a large selection of economically important estuarine fish species.
3. To investigate the usefulness of these data as indicators of biodiversity and sustainability, and possible inclusion as performance indicators in management of estuaries.
4. To provide a comprehensive set of environmental data relating to each sampling location, including water quality and habitat quality parameters.

Developing indicators of recruitment and effective spawner stock levels in north Queensland east coast prawn stocks

Project number: 1997-146
Project Status:
Completed
Budget expenditure: $154,654.00
Principal Investigator: Clive Turnbull
Organisation: Department of Primary Industries (QLD)
Project start/end date: 9 Aug 1997 - 15 Mar 2006
Contact:
FRDC

Need

In order to establish stock status, supply accurate advice and recommendations on management and monitor effectiveness of management intervention if need be, there is a need to develop procedures which

a) allow definition of the relationship between parent stock and recruitment levels in commercial prawn species, using fishery independant surveys as a means of determining recruitment levels

b) determine the status of these species and evaluate the potential risk of overfishing

c) develop methods which can used to evaluate the effectiveness of management intervention, if and when such intervention occurs.

Objectives

1. To develop fishery independent sampling procedures that can be used as robust long term methods for monitoring recruitment levels in the tiger and endeavour prawn fisheries located along the northern Queensland east coast and in Torres Strait.
2. To obtain a series of (fishery dependent) indices of spawner biomass and (fishery independent) indices of recruitment which can be used to generate a long term data series.
3. Incorporation of the indices obtained in objective 2 into a stock - recruitment curve, an index of stock sustainability and an assessment of the risk of recruitment overfishing facing each of the species.

Final report

ISBN: 0-7345-0298-2
Author: Clive Turnbull

Developing indicators of recruitment and effective spawner stock levels in eastern king prawns

Project number: 1997-145
Project Status:
Completed
Budget expenditure: $270,644.00
Principal Investigator: Tony J. Courtney
Organisation: Department of Primary Industries (QLD)
Project start/end date: 22 Jun 1997 - 13 Jan 2004
Contact:
FRDC

Need

The eastern king prawn is the Australian east coast's single most valuable fish species. On the basis of previous experience and existing data, the risk of overfishing this stock is unquantified but appreciable. Obtaining data which can be used to advise fisheries managers on the necessity of intervention can only be obtained from a focussed, directed multi agency study.

In order to establish stock status, supply accurate advice and recommendations on management and monitor effectiveness of management intervention if need be, there are needs to develop procedures which;

(a) allow definition of the relationship between parent stock and recruitment levels in eastern king prawns, using fishery independent surveys as a means of determining recruitment levels.

(b) determine the status of the species and evaluate the potential risk of over-fishing.

(c) develop methods which can be used to evaluate the effectiveness of management intervention, if and when such intervention occurs.

Objectives

1. Develop procedures and protocols for measuring a fishery independent index of recruitment in eastern king prawns.
2. Develop a program designed to monitor long term recruitment levels and changes in recruitment levels of eastern king prawns.
3. Identify indices of effective spawning stock abundance for eastern king prawns in anticipation of the need for managing to increase spawner biomass.
4. Undertake preliminary investigations of larval and post larval eastern king prawns distribution and abundance as functions of depth, distance from shores and estuaries.

Final report

ISBN: 0-7345-0218-4
Author: Tony Courtney

Definition of effective spawning stocks of commercial tiger prawns in the NPF and king prawns in the eastern king prawn fishery: behaviour of post-larval prawns

Project number: 1997-108
Project Status:
Completed
Budget expenditure: $334,756.00
Principal Investigator: David Vance
Organisation: CSIRO Oceans and Atmosphere Hobart
Project start/end date: 22 Jun 1997 - 12 Nov 2001
Contact:
FRDC

Need

In the Northern Prawn Fishery and the East Coast King Prawn Fishery managers have concerns about declining levels of recruitment to the fishery, and the lack of knowledge of the relationship between spawning stock and recruitment to the fishery. In both fisheries, the increase in effective fishing effort due to the use of GPS plotters and other modern technologies means that measures will inevitably have to be taken to reduce effort in the future. A more accurate definition of the real spawning stock would allow management to more effectively protect spawning stock and maximize catches by ensuring that critical areas were not overfished while allowing fishing in non-critical areas. Clear identification of the critical spawning areas would also allow managers to determine if changes in annual recruitment were due to changes in levels of spawning stocks.

The CSIRO hydrodynamic model of Albatross Bay (and models being developed for the entire Gulf of Carpentaria) have the potential to allow managers to more accurately define the effective spawning stocks for tiger prawns, but are limited by our lack of knowledge of a critical piece of postlarval behaviour: the timing of the change in vertical migration behaviour from being day-night cued to tidally cued.

The research proposed for eastern king prawns is particularly important, not only because it provides information relevant to improving the management of the East Coast King Prawn Fishery, but also because it will allow us to validate the techniques used in obtaining the behavioural data on tiger prawns for the Northern Prawn Fishery (see Methods).

Objectives

1. Measure the critical vertical migration behaviour of postlarval tiger and king prawns that determines their inshore advection patterns.
2. Incorporate this behaviour into hydrodynamic models to accurately estimate the effective spawning stocks of tiger and king prawns.

Final report

ISBN: 1-876996-03-X
Author: David Vance
Final Report • 2001-10-05 • 1.90 MB
1997-108-DLD.pdf

Summary

To effectively manage most fisheries, including penaeid prawn fisheries in northern and eastern Australia, it is important to know the relationship between the size of the spawning population and the number of young adults that recruit to a fishery in the next generation. In the tiger prawn fishery in the Gulf of Carpentaria, it has been assumed for management purposes that the total adult population at a particular time is the effective spawning stock, i.e. all spawners contribute to the next generation's stock. This is not necessarily correct and is particularly unlikely for many species of penaeid prawns, whose larvae and postlarvae have to migrate from offshore spawning areas to coastal and estuarine nursery areas. The area that contains spawners that actually contribute offspring to subsequent adult populations has been termed the effective spawning area.

The main aim of our project was to investigate the vertical migration behaviour of postlarval penaeid prawns that enables them to recruit from offshore spawning areas to the coastal nursery areas. We used two strategies to achieve this aim: field sampling in estuaries in southern and northern Queensland and laboratory experiments.

Keywords: Effective spawning, prawns, postlarvae, behavior, vertical migration.

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