The Shark Bay Prawn Fishery and the Shark Bay Scallop Fishery operate in the same general areas of Shark Bay (although there are some differences in their areas of operation). Recently, the Ministry of Fisheries has received presentations from both sectors on the ongoing interplay of fisheries and their respective management settings.
INTRODUCTION
R EASONS FOR R EVIEW
T ERMS OF R EFERENCE
R EVIEW P ROCESS
HISTORICAL BACKGROUND
In December 1982, the Minister of Fisheries and Wildlife announced the appointment of the Scallop Fishery Management Working Group. The working group was to investigate the commercial exploitation of the mussel fishery in Shark Bay and the Abrolhos Islands.
DESCRIPTION OF THE SHARK BAY PRAWN FISHERY
Over time, the fleet has gradually reconfigured to deal with these recruiting variations, mostly by providing "fallback" options in other scallop fisheries - notably the Abrolhos Islands and the trawling fisheries in the Midwest and the south coast (Esperance) scallop fishery, but also in some shrimp fisheries. Like the shrimp fleet, the scallop fleet is now feeling the effects of high fuel prices, although the impact of the fuel price is not as great in the scallop fishery – mainly because when the scallop fishery is in 'hyper abundance' (as happened in two recent years with the Abrolhos) their catch costs are significantly lower than shrimp fisheries (with their more stable recruitment/fixed catch mode due to shrimp migration to the trawling grounds) and when scallops are in small numbers, the scallop fleet simply stops with fish.
DESCRIPTION OF THE SHARK BAY SCALLOP FISHERY
CURRENT MANAGEMENT FRAMEWORK
S HARK B AY P RAWN
S HARK B AY S CALLOP
CURRENT RESEARCH PROGRAM
COMPLIANCE
OVERVIEW OF SUBMISSIONS
The entry references the many previous warnings to the scallop fleet about the ability of Shark Bay's scallop resource to generate regular or profitable income. The entry also describes past concessions by the shrimp fleet to support the scallop fishery [such as giving access to scallops to Denham Sound early in the season while the shrimp are not active], resulting in shifts in equity arrangements between the A class and B class. class fleets.
MANAGEMENT ISSUES
- S CALLOP R ECRUITMENT
- G EAR I NTERACTIONS AND F ISHERY I NTERRELATIONSHIPS
- Impact of Scallop Gear on Prawns
- Impact of Trawl Gear on Scallops
- S CALLOP C ATCH S HARE
- P RAWN F ISHERY S USTAINABILITY
- E CONOMIC I SSUES
- Prawn Trawling
- Scallop Trawling
- S CALLOP G ROWTH -M EAT C ONDITION -R EPRODUCTIVE C YCLE
- E NVIRONMENTAL AND C ONSERVATION I SSUES
A notable exception to this is the deep sea tiger prawn fishery in the Quobba area during the early part of the prawn fishing season (March). Again, it is not clear how this affects the fate of buried shrimp in the path of the net (but it could also be responsible [or at least suspected] with a targeted research program)3. The profitability of the Shark Bay Prawn and Scallop fleets has declined significantly over the past few years due to falling prices and rising costs.
Production is usually spread over 8 months of the year with the season starting in mid-March. However, this represents only about 6 percent5 of the total gross value of production of shrimp fishermen, so it is a relatively small part of the economic equation in shrimp fishing. The main characteristic of the catch in the Shark Bay area is the "spike" of production around 1991, which lasted for a period of about three years.
Based on the above, it is possible to calculate the following index9 of catch according to fuel consumption. This is because the adductor muscle tissues are used as a store of nutrients to "drive" gamete production and the long period of gamete production during the spawning period from April to November "dries up" the adductor muscle. A better understanding of this phenomenon could help to "micro-manage" the scallop fleet and improve the yield of the fishery.
FUTURE MANAGEMENT DIRECTIONS
I NTRODUCTORY C OMMENTS
M ANAGEMENT O PTIONS
- Scallop Fishing Season
- Trawl Closure
- Formalised Scallop Catch Share Arrangement
- Quotas
- Unitisation of Head Rope Entitlement
- Buy-Back
- Gear Controls
- Single Trawl Fleet
- Integrated Scallop Management
- Other Measures
The majority of the options target the scallop fishery given the problem of scallop recruitment and the interrelationship between A class and B class scallop licensees. In just a few of the last 20 years (1984 and 1992 [and maybe 1987]) - when the recruitment of the fish stock in the previous year was so great that it reduced the capacity of the shrimp and scallop fleets to fish it down - the scallop fishery has had a significant number of older (1+ age range) scallops in the fishery. Note that, if appropriate catch limits were applied to the scallop fishery early in the year, it would be possible to pass some of the 1+ scallops to the shrimp fleet).
In 2003, there were seven times as many scallops in the closed area than at the beginning of the closure. There are substantial differences in the life history characteristics of the two species discussed above compared to Amusium balloti - the scallop species found in Shark Bay - that need to be recognized. Traditionally, the shrimp boats started fishing for shrimp before the opening of the scallop season and the operational areas of shrimp and scallops have some overlap.
In the case of scallop fisheries, there is a reasonably well-developed catch forecasting system, which could be adapted to a quota or catch management scheme.
FUTURE RESEARCH DIRECTIONS
There are a number of other less drastic changes that could be considered to help improve the overall management of the fishery. It is important that permit holders within the Shark Bay shrimp and scallop fishery and the Department of Fisheries (including the Department of Research and Fisheries Management Services) are clear about their respective roles and responsibilities and the overall governance arrangements for managing the fishery. Fishery dependent data is one of the most important data sources used to manage fisheries.
There is an urgent need to develop an understanding of the level of gear interaction between the shrimp and scallop sectors and whether this may account for the recent low recruitment of scallops and subsequent catches in the fishery, and whether the scallop fishery has a negative impact on shrimp. Both the shrimp and scallop sectors support the need to fully and rigorously address the issue of gear interactions in those areas of the fishery where the distributions of the target species overlap. Several research gaps in relation to gear interactions will be addressed as part of the proposed FRDC grant application to be submitted for commencement in 2007/08.
Another objective of the proposed FRDC project is to develop an understanding of the oceanographic effect on recruitment in Shark Bay, which may help determine the reasons for the continued low level of scallops in the bay.
NEXT STEPS
An analysis of improved fishing effort is required to ensure that catch rate thresholds used for management purposes remain appropriate. Vessel gear configurations and impacts of other boat changes on fishing effort should also be monitored, particularly given the need, as outlined above, to ensure that fishery-dependent data remain useful. A number of other research needs were highlighted by the Department of Fisheries, including a review of the logbook data and improved Geographical Information System (GIS) analyses, and an analysis of existing data (logbooks and surveys) including assessment of day-night catch patterns for scallops.
With regard to scallops in particular, and in addition to the above, the research department suggests that previous biological studies may need to be supplemented by more recent biological information on scallops, particularly flesh weight and reproductive cycles in relation to spatial and temporal changes that recently have been sighted in Denham Sound, North West Peron and Red Cliff.
Large-scale closed areas as a fisheries management tool in temperate marine systems: The Georges Bank experience. Larval migration of the sea scallop, Placopecten magellanicus at Georges Bank: a model study of the roles of mean adhesion, larval behavior and larval movement.
SHARK BAY PRAWN AND SCALLOP FISHERIES DRAFT
CompetitiveTAC should be determined cautiously in the initial years due to uncertainty in forecast accuracy. In the shrimp fishery, consider progressing unification as a priority [considering the flow to Class B scallop license holders] along with streamlining gear configurations across the fleet. 6. Buyback.• Industry-driven restructuring through industry-financed buyback (direct license buyback and net allocation).
Formally merge the two management plans to establish a single trawl fishery in Shark Bay.• Reduce gear interaction. Integrated Scallop Management.• Formal amalgamation of all existing scallop fisheries to create one multi-zone scallop management plan within the fishery (alternatively focus on formal integration of Shark Bay and the Abrolhos Islands). 10. Management Plan Adaptations.• You need more management plan flexibility for space/time closures and for the ability to implement different management arrangements for Class A and Class B licensees.
Can affect efficiency and therefore it may be necessary to increase gear size to compensate for these efficiency changes.
MANAGEMENT OPTION – ADJUSTMENT TO
Frame opening – B class High >500t. March, but depending on the phase of the moon Middle <200t. less abundant and/or smaller 0+).
UNITISATION OF HEAD ROPE ENTITLEMENT –
Similar to the shrimp proposal, the configurations of the scallop gear can be changed to increase the capacity of the trawler, thus allowing the structural adjustment of the fleet from 14 vessels to, say, 9 vessels. In this scenario, one option might include changing the scallop gear specification from two seven-foot meshes to four 4.5-meter meshes. The following analysis is undertaken under the assumption that fishing hours will need to increase by 56 percent, which is the rate at which the fleet has been reduced and a higher rate than assumed in the shrimp industry (20 percent increase in fishing hours).
It is also believed that this configuration would result in a 50 percent increase in catch per vessel, due in part to an improvement in the average catch and availability of scallops as more vessels leave the fishery. This equates to a four percent return on investment in median years and a return on investment of eight percent in median years, assuming that the equipment rights are worth $3.1 million13 after consolidating the value of the rights (at a ratio of of 14:9 ). Although the reform does not significantly change the return on investment (from two percent to four percent in median years), as it does with shrimp, it significantly increases net profit per vessel.
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