The Torres Strait tropical rock lobster Panulirus ornatus (TRL) fishery is of immense social, cultural and economic importance to the region’s Indigenous fishers from both Australia and Papua New Guinea (PNG). During 2020, the COVID-19 pandemic indirectly impacted this fishery as well as a number of other fisheries reliant on international export markets. The TRL fishery is managed using an empirical (data-based) Harvest Control Rule (eHCR) to rapidly provide a recommended biological catch (RBC), based on catch, fishery-independent survey indices and catch-per-unit-effort (CPUE). Here, we summarize the impacts of COVID-19 on each of these critical data inputs and discuss whether the eHCR was considered adequately resilient to this unprecedented disruption to the system. Next, we use a quantitative supply chain index to analyze the impact of disruptions to the supply chain, and inform on potential adaptation strategies. The catch and CPUE data were impacted to varying degrees by external constraints influencing fishing effort, but the fishery-independent survey wasn’t affected and hence there remains an unbroken survey time-series for the fishery extending back to 1989. The eHCR was shown to be reasonably robust because it incorporates longer-term trends over a 5-year period, and accords substantially more weighting (80%) to the fishery-independent survey rather than CPUE data which can be affected by trade and other disruptions. Despite the eHCR not having been tested for scenarios such as a global pandemic, this robustness is a positive given the types of disruptions we will likely face in future climate. The weak links identified in the supply chain were the same as those previously highlighted as sensitive to climate change disruptions. Our supply chain analysis quantifies the impact on system resilience of alternative paths connecting producers to consumers and reinforces that supply chains may be particularly vulnerable to external disruptions if they are not sufficiently diverse.
Fishery-independent scientific surveys are highly valuable for monitoring lobsters and other fisheries. Yet, there are relatively few long-term monitoring surveys to support the provision of management advice. A number of challenges can prevent the continuity of long-term monitoring series. This paper uses the 35-year continuous annual dive surveys for Australia's Torres Strait tropical rock lobster (TRL) to overview strengths and limitations of a long-term scientific survey, as well as lessons learnt from having overcome a range of challenges. Fishery-independent surveys are more reliable than fishery-dependent data and are more robust to external shocks such as market drivers and fuel prices. The primary purpose of the surveys is to provide a reliable index of stock abundance together with data to inform on size and age structure, plus model parameters and reference points. Here, we also highlight additional survey benefits including: yielding positive gains relative to cost, facilitating an adaptive management approach that serves as an early warning system, reducing and resolving inter-sector conflicts, reduced frequency of stock assessments, providing data from associated habitat monitoring, improved stakeholder buy-in, utility for development of Operating Models for Management Strategy Evaluation, contribution to achieving certification, contributing to biodiversity agreements and consistent cross-jurisdictional monitoring. We analyse lessons learnt from challenges such as changes in resource management, budget cuts, increased health and safety requirements, maintenance of capability and staff capacity, stakeholder buy-in, need to validate survey results, a pandemic and changing climate. Our experiences highlight why long-term scientific surveys are considered the gold standard for fisheries monitoring and we provide insights for building and maintaining key marine monitoring series.
We used nucleotide sequence data from the ribosomal RNA (rRNA) gene cluster to determine the affinities of rhizocephalans reported to be Sacculina carcini which parasitize different portunid hosts: the green crab Carcinus maenas from Sweden; C. maenas from England; Liocarcinus marmoreus from Ireland; and Liocarcinus holsatus from Wales. There were no differences in nucleotide sequence data from the 3′ region of the small subunit (SSU) (160 bp) and internal transcribed spacer 1 (ITS1) (274 bp) rRNA of these parasites. The same region was sequenced from Sacculina granifera from Queensland, Australia, parasitic on Portunus pelagicus; Sacculina oblonga from Kyushu, Japan, parasitic on Cyclograpsus intermedius; and an undescribed rhizocephalan from Victoria, Australia, parasitic on Nectocarcinus integrifrons. The consensus nucleotide sequence of S. carcini from the ITS1 rRNA differed from S. granifera by 52% (146/282 sites), from S. oblonga by 56% (162/289 sites) and from the rhizocephalan from N. integrifrons by 33% (94/284 sites). The consensus nucleotide sequence of the 3′ region SSU rRNA of S. carcini and the rhizocephalan from N. integrifrons, which included the V9 domain, differed from S. granifera and from S. oblonga by 6% (9/160 bp). The high divergence rate of ITS1 rRNA sequence between species of Sacculina makes it a valuable diagnostic tool for parasites in this genus. On that basis, the nucleotide sequence data suggest that S. carcini infests at least two genera of crabs from a broad geographic distribution. This may limit the use of this parasite for biological control of introduced populations of green crabs.
Abstract Black teatfish ( Holothuria whitmaei ) is a high value sea cucumber that has been listed under the Convention on International Trade of Endangered Species (CITES) Appendix II. The Black teatfish fishery in Torres Strait, Australia, is fished solely by Indigenous Torres Strait Islanders. Black teatfish were closed to fishing in 2003, based on the results of stock surveys and concerns of overexploitation. A stock survey in 2009 found the Black teatfish population had recovered substantially but the fishery was again closed after trial openings exceeded catch limits. In line with a new harvest strategy adopted for the fishery in 2019, we conducted a stock survey in 2019–2020 that suggested the stock had recovered sufficiently to support a sustainable catch limit of 20 t. Empowering Indigenous Torres Strait Islanders to use Island custom alongside western management strategies, contributed to the success of a trial opening in 2021. The combination of a harvest strategy developed in consultation with traditional owners, a rigorous scientific survey and trial opening protocols informed by Island custom, supported the CITES positive Non‐Detriment Finding for the Torres Strait Bêche‐de‐mer Fishery. This is a significant example of the successful recovery and ongoing sustainable management of a depleted sea cucumber population.
Plaganyi et al. (1) show that a rotational zone strategy (RZS) applied to sea cucumbers in a multispecies fishery on Australia’s Great Barrier Reef significantly reduces the risk of overall and localized species depletion in the fishery. In addition to implementing limits on catch and minimum size, Plaganyi et al. (1) advocate designs of RZS that ensure effort is spread throughout the fishery so that the entire population of patchily distributed species periodically has a chance to grow and breed unfished. Purcell et al. (2) counter that this approach is risky and raise six concerns.
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)
