Management strategy evaluation of the Queensland east coast sea cucumber fishery, with data to June 2023

Abstract

The Queensland Sea Cucumber Fishery is a recreational and commercial fishery comprised of twenty-one sea cucumber species. The fishery has a dynamic history of species catch composition whereby the main target species were black teatfish (Holothuria whitmaei), then white teatfish (Holothuria fuscogilva) and presently burrowing blackfish (Actinopyga spinea) with opportunistic harvest of herrmanni curryfish (Stichopus herrmanni) and prickly redfish (Thelonata ananas).

This is the second management strategy evaluation conducted on the Queensland sea cucumber fishery but the first by Fisheries Queensland. A management strategy evaluation of the Queensland sea cucumber fishery conducted by CSIRO in 2014 evaluated the benefits of the rotational harvest strategy (Skewes et al. 2014). While some specific results differ between the previous and current management strategy evaluation are difficult to compare as fishery reference points have been updated between reports, consistent conclusions were reached.

Management strategy evaluation is a simulation tool for comparing the effectiveness of different management procedures against fishery objectives. The simulations capture the growth, reproduction, movement and mortality of a fish population and potential management procedures which dictate the fishery
operating on the population. Uncertainty in these processes is characterised by running many simulations with slightly different biological specifications. The management procedures prescribe a mode of operation rather than a specific catch-limit or effort control. The performance of each management procedure is quantified to answer important management questions. Management procedures that perform well over a range of simulations are more likely to achieve the desired management goals. Well-performing management procedures become recommendations for the fishery.

This management strategy evaluation was undertaken using the openMSE package developed by Blue Matter Science.

The evaluation considered commercial catch and effort data spanning 1995 to 2023, biological data provided by Fishwell Consulting and Macquarie University and results from co-produced stock assessments.

The biology of many sea cucumber species is unknown or uncertain and often places this taxon in a data-limited space. This applies to many species in the Queensland sea cucumber fishery and the data-limited nature of the fishery has been captured in this management strategy evaluation through an increased level of uncertainty for species biology.

This management strategy evaluation found that the settings contained in the harvest strategy and other legislated and enforceable management arrangements are likely sufficient to meet the fishery’ objective of attaining maximum economic yield (defined in the harvest strategy as target biomass level of 60% of unfished biomass for stocks harvested in the fishery). The current management containing the rotational harvest strategy, catch limits and size limits management arrangements suggests the risk of depletion for most species was low.