This project provides the resources for JCU to establish and operate the Tropical Research Hub for the National Hatchery Network in collaboration with ASSA researchers for 18 months (until 31 March 2025) which is the stipulated grant duration.

This FRDC project will provide the funding for JCU to engage key technical capability needed to support the Hub and establish the facilities for exclusive and continuous use for the project over the grant period, as well as provide the facilities and services of the ASSA employees (~2) working at this Hub.

The core objectives of the Research Hub will be to:
1. Establish facilities and equipment required for the development of the Tropical Seaweed Research Hub
2. Deliver a focused research program to close the life cycle, of Asparagopsis taxiformis, with the goal of being able to produce spores and seedlings.
3. Develop biological contamination management techniques for seed production.
4. Collect and maintain a clean broodstock culture collection.
5. Develop hatchery technology and equipment needs through experimentation.
6. Contribute to the development of a Hatchery Manual and knowledge sharing and dissemination.

The establishment of foundational seaweed hatchery capabilities at a strategic location in the Tropics, alongside the accelerated availability of seedstock and the provision of guidance in hatchery design and techniques marks a pivotal advancement in the journey of the seaweed industry in Australia. The Tropical Research Hub at JCU will help ensure sustainable industry growth by addressing the emerging R&D challenges surrounding hatchery techniques, strain selection, and seed production of Asparagopsis taxifomis. Moreover, it will foster a collaborative relationship between industry stakeholders, governments, and research institutions, promoting the development and progress of seaweed cultivation.

As a species listed under CITES Appendix II, SHH are harvested under a total allowable catch of 200t, which was implemented for Australia to meet its obligations under non-detriment findings. Further, the conservation status of SHH is currently being reassessed under the EPBC Act. A recent SHH stock assessment undertaken using data poor methods highlighted the paucity of data available for the species and, importantly, that informative data will almost certainly not be available in the foreseeable future. Therefore there is no expecation that current uncertainty will resolve with status-quo data collection strategies.

New approaches, such as CKMR, are required to gather informative data to better understand stock status and verify that the 200t catch limit is appropriate. The project proposed here aims to explore likely scenarios to determine the sample size, budget, and required sampling logistics in order to obtain either an estimate of spawning abundance of SHH stocks found in northern Australia, or to determine that the current catch limits will not be detrimental to the sustainability of the species. This project intends to utilise available fisheries observer data and the current understanding of population trends and demographic information to evaluate

(1) whether the species is a viable candidate for close-kin mark-recapture assessments, and

(2) the extent of sampling required to produce a precise estimate of population abundance and/or other population metrics useful for management.

Catch Per Unit Effort (CPUE) from commercial logbooks is often used as an index of abundance in stock assessments. However, the use of commercial CPUE as an indicator of relative abundance can be problematic as the underlying assumption that commercial catch rates change linearly with abundance is often compromised. Although some factors that are reported in logbooks can be used to standardise CPUE, there are other sources of variation including:
• Modified fishing practices to target or avoid species to suit quota availability, meet market demands, or to comply with management arrangements.
• Differences in selectivity of fishing gear and use of bycatch-reduction devices.
• The combined impacts of multiple management restrictions on a fishery.
For example, gillnet operations in what was once the Northern Territory’s Shark Fishery now almost exclusively target Grey Mackerel. This change in practice has resulted in an index that is losing its relevance in assessing shark species.

Over 140 elasmobranchs are listed on CITES Appendix II, with the likely-hood that more species will be added in the future. Of the 11,082t of shark landed by the fishery since 2000, CITES listed Hammerheads comprise 17.25% of the shark catch. Other sharks caught by the fishery that were recently added to CITES Appendix II at the Nineteenth meeting of the Conference of the Parties Panama City (Panama), 14 – 25 November 2022 include: Grey Reef Shark, Dusky Whaler, Sandbar Shark, Lemon Shark, Whitecheek shark and all other members of the family Carcharhinidae (which include the Blacktip Shark complex that is the main shark species caught by the fishery - 4688t or 42% since 2000). These species will require a positive Non-Detriment Finding (NDF) and CITES export permit in order to be exported following the 12-month delay in implementation (i.e., December 2023). The fishery also catches Threatened, Endangered and Protected Elasmobranchs, some of which are also CITES listed.

Gillnet and longline effort has decreased since 2000 and there is significant latent effort in the fishery. There is a desire to utilise this latent effort, however, the CITES listing of the majority of sharks species caught in the fishery will increase scrutiny from State, Commonwealth and International environmental agencies, as well as NGOs. This heightened scrutiny will provide greater impetus to demonstrate that shark stocks are at sustainable levels and that fishing is being undertaken sustainably.

There is a strong need for independent survey methods to gain a better understanding of the abundance patterns of shark species over time that can contribute to the development of appropriate management of these species that meets environmental, fisheries, and conservation needs.

Surveying Northern Australia using longlining methods would provide a fishery independent estimate of relative abundance for sharks that would improve economic security and public confidence in sustainability. However, to make an informed decision of the feasibility of a survey a full understanding of the scope of work and cost required is needed. There is a need to look at existing long line surveys undertaken worldwide (e.g. in the USA and Bahamas), to understanding the methods undertaken and the time period required to develop accurate abundance estimates.