This document was prepared by the Department of Fisheries and is designed to encourage public participation in finalizing revisions to the fishing strategy and decision rules that will be used to manage the western lobster resource under the new quota-based management system. They often need to be translated into operational/management objectives that have direct and practical application to fisheries management and can be measured. This document describes a set of updated proposals for use within the Fishing Strategy and Decision Rules (HSDR) for the West Coast Managed Lobster Fishery (WCRLMF)2 that have been developed to facilitate the implementation of the new quota-based management system.
Setting an optimal legal catch (ie, to achieve relatively high catch rates) would be expected to result in the rock lobster industry actually achieving high economic returns from the fishery.
The limit of the managed lobster fishery of the west coast and the main management areas, A, B and C. The fishery has recently changed from a total allowable effort (TAE) system, based on a sophisticated set of entry controls, to a results-based system management system that uses catch limits. It is planned to move to full management based on Individual Transferable Quotas (ITQ) in 2013, while still retaining some necessary entry controls.
The fishery is divided into three major zones (A, B and C, Figure 1b), which help distribute effort across the fishery and allow the implementation of different management controls to address zone-specific issues. Recreational rock lobster fishermen mainly target lobsters in relatively shallow water with the highest fishing effort around the coastal urban centers, e.g. Bunbury, Mandurah, Fremantle/Perth, Jurien and Dongara/Geraldton and on average account for about 3-4 per cent of the total catch.
Resource sharing
For further information on the commercial and recreational fisheries see the State of Fisheries and Aquatic Resources report at http://www.fish.wa.gov.au/docs/sof/index.php?0706.
For harvesting strategies to be effective, the level of an indicator must be interpreted in relation to the operational objective by determining what describes acceptable performance compared to unacceptable performance. The reference values can be a target (where you want the indicator to be), a threshold (where you review your position), or a limit (where you do not want the indicator to be), which is used to guide what management actions are required. It represents the desired or optimal condition to produce the best results that meet the specific objectives of the fishery.
Limit The limit is the level of the indicator below (or above) the level at which the abundance of the stock is considered unacceptable for one or more objectives (sustainability of the stock, legally harvested share, etc.) and for which a strong set of management measures would be necessary. immediately implemented to reduce the fishery/stock to an acceptable level or at least above the threshold. The selection of the indicator and performance limits should be done as a package together with the determination of the level of complexity and precaution of the management strategies and measures. The accuracy of both the indicator and the performance levels used in assessments should match the level of precaution used in management settings.
Decision rules describe management strategies or actions (eg, setting a TACC level) that are predetermined to be performed based on the current or predicted level of an indicator relative to limit, threshold, and target levels ( performance). Decision rules for a fishery will be developed such that if the indicator is at an acceptable level, management actions will be designed to keep it there, but if it is at an unacceptable level, management actions will be designed to return it to an acceptable level within a reasonable time frame. In general, higher levels of accuracy and certainty in performance indicators and values enable the development of more defined rules for management decision-making and response.
Previous decision Rules for the Western Rock Lobster Fishery
Management objectives
Proposals
For Breeding Management Areas 2, 3 and 4 (Figure 2), it is proposed that the limit value for egg production be based on the mid-1980s level (Table 1). This period is considered a period of relatively low exploitation in fisheries (especially in deeper water breeding stock areas) that preceded the widespread adoption of major technological innovations such as GPS, high-resolution color echoes and computers. Unlike females that breed in B and C coastal areas, most females in BSMA 3 start breeding below the legal size, so the brood stock in BSMA 3 is not depleted by fishing to the same extent as in other BSMA areas .
Fishing limits were set at 20% below the limits for each of the BSMAs. Given that the proposed sustainable goal is to keep egg production above the threshold at all times, it is highly unlikely, barring some catastrophic event, that egg production would exceed the threshold level. BSMA1 Deep water areas north of 28°S Preliminary assessment only in the mid-1990s, but will be revised when multi-year survey data become available.
Ensure that egg production in the breeding stock management areas (2-4) of the fishery (see Figure 2) remains above the threshold for the next 5 years at a 75% confidence level. If egg production in a BSMA is predicted to fall below the threshold, management measures will be taken to ensure that this does not happen. A breach of the limit value in any BSMA will result in significant and immediate management action.
Legal Proportion harvested objective
Legal Proportion harvested indicator
In addition to meeting the sustainability objective, TACCs set for fisheries should aim for an optimal legal catch range that would provide catch rates that would ensure high economic returns from the fishery. The target legal catch will initially be set at 0.5, and the range will be ±0.05 of the average legal catch (eg green area in Figure 4). The TACC set to achieve the target legal harvest share (ie within the range) would normally be lower than that required for sustainability; however, if there is a conflict, the goal of sustainability must be achieved first.
The level of variability in TACCs between years in each zone should be minimized (eg, vary by less than 20%) to support economic performance.
Legal Proportion harvested and Fishery Performance
The greater the abundance of lobsters, the higher the catch rate, which usually results in higher economic returns from the fishery. Higher catch rates would also benefit recreational anglers and provide a more satisfying recreational fishing experience (ie, participants would be more likely to catch lobster when abundance is higher). In comparison, a high legal catch ratio usually results in fewer lobsters remaining on the property at the end of the year, thus reducing abundance, including the abundance of the brood stock.
The lower the lobster abundance, the lower the catch, which usually results in lower economic returns from the fishery and lower catch rates for recreational anglers.
Zone C taCC setting
Fixed proportional taCC between Zones a and b
A critical element of this proposed harvest strategy is that fisheries managers, in consultation with stakeholders, will under normal circumstances be in a position to take management actions before any egg production or legal proportion of stripped indicator exceeds its reference value, threshold, limit. and target respectively. If an egg production indicator value is predicted to exceed the threshold over the next five years, this will trigger a management response to correct it. The management response to increase egg production (i.e. rebuilding a hatchery stock in a specific BSMA) may involve reducing a Zone's TACC by more than 20% (if necessary) and/or introducing other management measures.
If a breach is predicted to be in the short term (one or two years), this would trigger an immediate management response to correct it, compared to if the breach was predicted to occur in four or five years. A violation or anticipated violation of a limit value in any BSMA would trigger significant and immediate management intervention, such as large-scale site/site closures or significant TACC reductions or both. Assuming that there are no stock sustainability issues, where the value of the indicator collected from the legal ratio was in violation of its target range, or predicted to be at some stage during the next five years, management responses to correct it (ie to get an area or region back into its target range) would not involve changes in TACC of more than 20% in any year.
In practice, the TACC setting decision rules will work by first determining whether the projected indicator of the harvested share is within the range of the harvested statutory share. It is expected that once a TACC has been established so that the indicator falls within the legal range of the harvested share, further adjustments to the TACC to ensure that the egg production indicator is above the threshold will generally not be necessary. A flowchart outlining how the TACC setup decision rules would work in practice is shown in Figure 5.
Zone C decision Rules
Zones a and b decision Rules
Increase or decrease the TACC by increments ≤20% to bring the legal proportion harvested back within the target range. A three-year bioeconomic project to develop better economic information for the lobster industry to help optimize the lobster harvest is currently underway.
Marine Stewardship Council, 2006, Western Rock Lobster Fishery, MSC Re-Certification November 2006, Marine Stewardship Council: http://www.msc.org/track-a-fishery/certified/. Report of the President to the Minister of Fisheries on management recommendations for the 1993/94 and 1994/95 seasons.
