• Change text size
• Skip to content

Fisheries and the environment

Search:

• About us
• Contact us

2. Assessment of the fishery against guideline components

In this section, a short comment is provided against each of the relevant components of the Guidelines for the ecologically sustainable management of fisheries, providing the context for recommendations where they are made.

• Principle 1
• Principle 2

1. Principle 1

• 1.1 Objective 1
• 1.2 Objective 2

1.1 Objective 1.

• Information requirements
• Assessment requirements
• Management responses

Current management objectives relate to sustainable levels of catch for the fishery. They are based on reference period of high catches, and a period in which there has been lower catch levels under state-wide Total Allowable Catch (TACs). Controls include limited entry to the fishery, with a fixed number of entitlements, coupled with output controls that include TACs and Minimum Legal Size limits that are developed to reflect regional differences in growth rates. Some of the slow-growing blacklip components do not reach the minimum size limits that otherwise apply, and have been harvested under specific localised fish-down arrangements.

Current management strategies, including TAC levels and the specific size limits that are applied, are intended to provide protection for the majority of animals for two spawning seasons post maturity, and to provide for a minimum of 40% of unfished egg production.

There has been a recent increase and then a decrease in the TAC for H. rubra following concerns over catch levels in productive areas of the Eastern Zone. Earlier in the fishery, concerns over changes in patterns of catch and catch rate for greenlip abalone had led to the development of finer spatial controls and catch capping, and more conservative size limits. In general, greenlip abalone are considered to be more vulnerable to localised depletion than blacklip. There are continuing concerns about the levels of precaution inherent in current targets for protection of animals for two years post maturity and the levels of egg production conserved.

There is at present no formal risk-based assessment, with a risk analysis identified in the strategic research plan as a gap. There is cooperation by Tasmanian abalone researchers and managers as part of an FRDC funded project on the development of robust population modelling and simulation approaches to assessment of options and associated estimates of risk for catch levels and management actions. Once developed and tested for application in local populations, that should provide an improved basis for the assessment of risks associated with proposed management arrangements.

Uncertainties in estimates of pre-harvest population levels and densities will complicate development of system-based biological reference, target and trigger levels but should not preclude the development of a robust approach that is more system-based.

System-based management objectives and performance measures

As noted, current management objectives are framed primarily in terms of sustaining particular threshold or levels of catches, with reference periods from the earlier phases in the commercial operations and adaptive shifts in response to indications of unsustainable catch levels. They are not explicitly system-based and related to the health and functioning of the broader system in which the fishery operates. That imposes some constraints on the development of appropriate biological reference, target and limit levels and risk-based decision rules for application in the fishery.

The Tasmanian management agency has undertaken to implement a review and development of management objectives to provide necessary system-based refinements. Once done, that will flow into other components of the management framework, including the development of more precautionary target and trigger levels. It is critical to the required shift in management.

Development of reference and limit levels will need to take into account emerging information on the need for increasingly conservative management for smaller populations units, particularly for those where abundance has been reduced to low levels relative to their unfished state.

Ensuring the capacity for effective management of catch/effort at the scale of local population units, particularly those considered to be below, or at risk of falling below, reference or limit levels, will be important, as will the development of strategies relating to the timely recovery of depleted components of the stocks.

Recommendation

1. Develop and provide, as part of the public review process for the management arrangements of the Tasmanian abalone fishery in 2004, proposed system-based management objectives for the fishery and an assessment of the options for associated biological reference, target and limit levels, and performance measures.

Information requirements

1.1.1 There is a reliable information collection system in place appropriate to the scale of the fishery. The level of data collection should be based upon an appropriate mix of fishery independent and dependent research and monitoring.

The current management framework provides sound basis for collection of catch and effort data from the fishery, with a level of cross-checking though pre- and post trip reporting and acquittal of logbook and processor returns. Recent implementation of fine-scale geographically-located returns will allow higher resolution for detection of local declines and signals from industry and independent surveys. The development of increased capacity to ensure longer-term fishery-independent surveys will be an important source of information, coupled with continuation of the commercial catch sampling and measurement program reinstated in 1998.

The scale of information collection at block or sub-block level may still be insufficient to pick up localised declines in highly productive smaller-scale patches at reef or embayment scale, but finer-scale recording of commercial activity has been implemented.

The most recent stock assessment, for the 200 harvest, was based principally on analysis of trends in the catch and catch rate of the commercial fishery, with size composition from research dive surveys in 1997. Targeted surveys and research in areas of particular concern in the South-east provided the basis for more specific management response in that area.

Balance between industry dependent and independent information

The current research effort provides a good framework for development of an effective industry-independent component to the assessment of stock status. Although a major series of independent surveys was discontinued in 1998, specific surveys in selected areas, such as Block 13, have been important in assessing the significance of observed changes in catches and catch rates. It is essential that a balance is maintained between industry dependent and independent research and monitoring.

Assessment of the reliability of industry-derived information, including catch returns and effort estimates, requires the development of long-term independent surveys. Encouraging progress is being made in the refinement of survey techniques which may provide sufficient power as indicators of change in exploited populations.

Recommendation

2. Continue development, implementation and maintenance of long-term industry-independent monitoring and field sampling of abalone populations, including the development of baseline monitoring of the population dynamics of abalone in areas closed to commercial operations.

Assessment requirements

1.1.2 There is a robust assessment of the dynamics and status of the species/fishery and periodic review of the process and the data collected. Assessment should include a process to identify any reduction in biological diversity and /or reproductive capacity. Review should take place at regular intervals but at least every three years.¹

Progressive refinement of the level at which management information is derived is evident, with adaptive management responses to identified issues, including improved management of the distribution of effort and access, following the initial implementation of major fishing zones for the 2000 season. Responses to indications of localised overfishing have included the imposition of zonal and sub-zonal caps on catches, with significant impacts on industry dynamics.

Development of annual assessment requires review of available information, rather than formalised periodic process of public review of assessments, their basis and of management arrangements, which occurs as part of the process of developing the management arrangements themselves. Assessment and advice to the management authority is based on suite of indicators, including catch, catch rate, size composition, including assessment of level of protection of egg production. The current assessment process does not allow assessment of level of risk of reaching trigger levels. Cooperative development of population modelling under national program should address refinement of risk assessment approach and its application to elements of the Tasmanian fishery.

Public review of information used in fisheries assessments.

The current processes provide for public consultation in the development and review of management arrangements and representation of a range of interest groups in the formal advisory groups that are established for the fishery. Public comment on the Report from DPIWE raised the issue of the availability for external review and assessment of information used in stock assessments and the possibility of routine public release of catch-related information.

There is an existing whole-of-government policy within the Tasmanian Government on privacy and confidentiality that bears on the release of some information from wild capture fisheries. The Tasmanian DPIWE provides information and data on fisheries, either free of charge, or as a fee-for service where there is commercial purpose, where necessary, under confidentiality agreements.

There is the potential for strengthened representation from conservation and broader community interests and to provide broader public notification of the annual process of assessment and review of management provisions. The management agency has indicated that it may be possible to incorporate some form of short public consultation phase in the development of the assessment reports by the Tasmanian Aquaculture and Fisheries Institute (TAFI).

The current process for stock assessments could be further strengthened by the incorporation of structured periodic external peer review.

Recommendation

3. Representation in the fishery assessment process should be increased to strengthen representation from conservation and other community interests. Consideration should also be given to broader public notification of the opportunities to provide input into the assessment process. The existing stock assessment process would be further strengthened by periodic peer review.

1.1.3 The distribution and spatial structure of the stock(s) has been established and factored into management responses

Early work on patterns of genetic relationships in Tasmanian blacklip indicated significant heterogeneity between sites; more recent work is equivocal and research is continuing, although primarily as a forensic tool for identification of product in trade. The markers used are currently under review. The most parsimonious interpretation of current information is of differentiation by distance, rather than a series of relatively discrete populations. Findings are consistent with limited linkage between metapopulation units and very limited capacity for large-scale source-sink dynamics capable of replenishing over-exploited components in the short-term.

Current primary management units are the three main zones (blacklip), implemented to address major imbalances in the distribution of effort. Catch and effort data are collected at block or, following modifications implemented in 2000, sub-block level, log book reporting providing finer resolution within blocks. The catch controls are not generally implemented at block level, but block or sub-block caps implemented where concerns over catch levels are identified. Controlled exploitation of slow-growing northern blacklip populations has been done at block level within zones under periodic fish-downs, the last in 1995.

Spatial scale in stock structure and the effective scale of management

Key issues in ensuring continued sustainability will be information on the scales of spatial structure in abalone stocks and the identification of effective local population units, coupled with information on the extent and status of abalone habitat.

An improved understanding of trends in fishing efficiency in the development of the Tasmanian fishery for blacklip and greenlip abalone is likely to continue to be important in developing reliable indicators of local abundance, in tandem with industry-independent monitoring. Collation of information on the patterns of effort and catch in the early phases of commercial exploitation may also provide useful information for understanding current patterns of local distribution, abundance and productivity in the fishery. It may be particularly important in refining development of standardised Catch Per Unit Effort series at appropriate scales.

Recommendation

4. Continue to develop methods to determine the patterns and scale of local population structure and productivity within the fishery and develop management techniques to take that spatial structure into account in implementing harvest strategies at the appropriate scales.

1.1.4 There are reliable estimates of all removals, including commercial (landings and discards), recreational and indigenous, from the fished stock. These estimates have been factored into stock assessments and target species catch levels.

Improved reporting and documentation provide a very sound basis for documentation of legal removals. Recreational fishing pressure is strongly seasonal, with more than 2/3 of the recreational catch coming from the more accessible East Coast. The most recent published assessment of recreational catch based on surveys in 1996/98, provides an estimate of 35 tonnes, or about 1.5% of commercial catch, with significant growth in the numbers of licenced recreational abalone fishers each year. There are some concerns at the possible impacts of sustained recreational fishing on areas that could continue below the operational limits for commercial operations, with potential for localised depletion. The recent national recreational fishing survey may allow updating and reassessment of current daily bag limits and other controls.

Aboriginal cultural fishing activities are exempt from the Tasmanian Living Marine Resource Management Act 1995 and there are no current estimates of the level of catch. The Tasmanian Aboriginal Cultural Fishing Advisory Committee has been involved (in 2000) in considering relationship with recreational and other fishery controls.

In discussions, the management agency stated that the current process necessarily builds in an assessment of the effects on abundance of all removals, including recreational and illegal catches, in indices derived from commercial catch returns and changes in size distributions. Of concern, however, is that catch and CPUE-related measures are an relatively blunt instrument and are unlikely to pick up other than major disruptions, which are as likely to be reflected in changed patterns of commercial effort. The current approach to stock assessment provides an indication of the response of abalone stocks to all removals, but is not in isolation capable of identifying the separate impacts of commercial take, recreational pressure and resource theft.

There is a good framework in place for reporting, checking and reconciling commercial catch data. As noted above, while there is no current structured monitoring of recreational catches, estimates of catch levels are based on periodic surveys, the most recent in 1997, which will be updated with more recent information now available.

The recreational harvest

A recreational licence is required to take abalone for recreational purposes, with daily bag limits and minimum size limits that apply. Numbers of recreational licences have increased substantially in recent years. While the overall level of recreational and traditional use is considered to be low, the effort is not evenly distributed and there is a potential for localised adverse impacts on areas that are particularly accessible. Periodic re-evaluation of levels of take and risk to local sustainability arising from recreational harvesting may be required to meet system-based management objectives when implemented.

Recommendation

5. Undertake periodic reviews of the extent of the take and level of recreational abalone fishing, and refine management measures if considered necessary

Resource theft - illegal abalone harvesting

The overall level of compliance within the commercial fishery and processing operations is considered to be good. There is continued concern at the potential impact of illegal operations. While estimating and tracking the extent and level of the illegal take continues to be extremely difficult, considerable resources are expended on compliance.

The compliance measures in the management arrangements have been developed over a considerable time to address the issue of illegal take. They are under constant operational review and are refined as management in the fishery develops.

A periodic structured evaluation of the compliance strategy and its performance will provide an opportunity to identify strengths and weaknesses of existing arrangements, and to recommend refinements.

Recommendation

6. The compliance and enforcement strategy should be periodically reviewed to ensure emerging compliance risks are identified and addressed.

1.1.5 There is a sound estimate of the potential productivity of the fished stock/s and the proportion that could be harvested.

Management is based on limited entry and output controls that include zonal catch limits and minimum size limits. The minimum legal length limits are varied geographically to take into account species differences and regional differences in growth rates and sizes at maturity.

There is no current estimate of the area of suitable habitat by block or sub-block and fishable area, density and overall abundance of the populations. There is no estimate of total removals as a proportion of standing biomass, other than indirectly though the general objective of providing a level of egg production greater than a proportion of pre-fishing egg production selected to reduce the risks recruitment failure.

There is however a good research and assessment framework. This framework could benefit through refinement to deal with the questions arising from hyperstability in abalone CPUE indices.

One of the primary indicators used in assessments has been CPUE, as an indicator of relative stock size. Reference catch levels for overall catches and catch rates are from two periods. One is the period 1979-82, when catch rates were increasing to a peak in the mid 1980s, with stock levels assumed to be stable. The other is 1992-1985, a period following progressive quota reductions and size limit increases. At that time, catches were at a 20-year low and [overall] stock was assumed to be stable. There are a number of contributing factors to changes in fishing efficiency: developments in technology and fishing operations; shifts in market preferences from larger to smaller abalone; and diver behaviour in targeting areas likely to yield higher catch rates, including aggregations, for example. These give rise to questions about the reliability of CPUE as an indicator of stock status in abalone, with indications of insensitivity, or hyperstability, to changes in stock abundance.

The use of corrected CPUE series now being examined by the agency should provide an improved basis for assessments. There are however, considerable difficulties inherent in interpreting indices derived from phases in the fishery before and after the introduction of TACs, differing zonal controls and market shifts that have had major impacts on industry practices. A preliminary assessment of effort creep (DPIWE 2001) for selected blocks provides, under one set of assumptions, an estimate of stock abundance 50% lower than that indicated from uncorrected CPUE relative to 1975. The issue is under active consideration.

Management controls are intended to ensure protection for two years post maturity, with minimum size limits adjusted for differing growth rates; and to maintain egg production at above 40% of unfished levels. Recent research elsewhere (Shepherd et al) indicate that local populations that are reduced, and initially small populations, may require higher levels of protection to reduce the risk of increased variability in recruitment and the risk of recruitment failure in successive years.

Management Responses

1.1.6 There are reference points (target and/or limit), that trigger management actions including a biological bottom line and/or a catch or effort upper limit beyond which the stock should not be taken.

Current measures include performance of CPUE against the reference periods, the requirement for size limits to provide 2 years protection post-maturity and the overall TAC. No other biological reference, target or limit levels are set currently, but review of management objectives will require reassessment of levels. There are no explicit recovery strategies, targets and timelines identified in the current management documents.

In the absence of more detailed information on populations dynamics, the use of regular re-evaluations of catch and effort data and a set of other indicators is proposed as an effective alternative to the development of more specific trigger and reference levels. Research is currently directed, in Tasmania and elsewhere, at the development of system-based biological reference, target and limit levels. There are management strategies in place capable of controlling the level of take and there is a sound framework, which will require refinement with the development of system-based objectives.

1.1.7 There are management strategies in place capable of controlling the level of take.

The current management framework provides a high-quality framework for collection of catch returns and recording by divers, processors and exporters. A system is in place for monitoring and assessment of levels of compliance, with linkage to the national docketing system. Information is available on the service agreement targets for a range of activities, but there is no assessment of performance against targets, or of trends in compliance, detection and deterrence. A current national study on compliance may provide the basis for local refinement of assessment of risks, but does not appear likely to provide robust estimates of the current regional levels of resource theft.

1.1.8 Fishing is conducted in a manner that does not threaten stocks of by-product species.

(Guidelines 1.1.1 to 1.1.7 should be applied to by-product species to an appropriate level)

There is very little bycatch, other than attached organisms that may be removed with the abalone. There are no by-product species and the Abalone Policy document sets out a framework that would not permit harvesting of other organisms in the abalone fishery.

1.1.9 The management response, considering uncertainties in the assessment and precautionary management actions, has a high chance of achieving the objective.

There is a good framework in place. Based on the progressive development of spatial controls over effort and catch, the proposed management arrangements would appear to have a high probability of achieving catches maintained at or near recent levels, in part by shifts in effort to currently more lightly exploited blocks, with capacity for increases from current levels. The extent to which that sustainable level of commercial catches represents levels that ensure the continued functioning of the species in the systems in which they occur remains to established.

1.2 Objective 2

.

• Management Response

Management responses

1.2.1 A precautionary recovery strategy is in place specifying management actions, or staged management responses, which are linked to reference points. The recovery strategy should apply until the stock recovers, and should aim for recovery within a specific time period appropriate to the biology of the stock.

The current management framework does not provide explicit recovery strategies or time periods for recovery of depleted stocks within the fishery. However, the fishery manager has demonstrated that they will act to change management arrangements when there are indications that the stock is not rebuilding at the anticipated rate or when there are indications of overfishing emerging.

The current policy document includes assessment of CPUE changes, estimates of egg production, a relative measure based on size/age distributions and maturity, and size composition in assessment of stock status. The primary recovery mechanism is catch limits by size by species, with size limits varied according to localised conditions and growth rates.

1.2.2 If the stock is estimated as being at or below the biological and/or effort bottom line, management responses such as a zero targeted catch, temporary fishery closure or a 'whole of fishery' effort or quota reduction are implemented.

The scale of effective action for localised populations is critical. Current mechanisms allow catch-capping, seasonal limits or closure at block and sub-block level, and are capable of refinement as management requirements are developed.

¹ Review should be undertaken by the relevant management authority in a transparent way

• Home

• Marine
  • Marine reserves
  • Marine bioregional plans
  • Marine pollution
  • Fisheries and the environment
  • Great Barrier Reef
  • International activities
  • Marine species
  • Publications and resources

• Fisheries and the environment
  • Open for public comment
  • Commonwealth managed fisheries
  • NSW managed fisheries
  • NT managed fisheries
  • QLD managed fisheries
  • SA managed fisheries
  • TAS managed fisheries
  • VIC managed fisheries
  • WA managed fisheries