Determining the impact of environmental variability on the sustainability, fishery dynamics and economic performance of the West Coast Prawn Trawl Fishery
Characterising the fish habitats in the Recherche Archipelago, Western Australia
Fisheries WA demonstrated in their Aquaculture Plan for the Recherche Archipelago (Fisheries WA 2000) that one of the major factors slowing development in this region is lack of accurate spatially explicit data on the distributions of benthic habitats and the influence of currents and wind generated waves. This information is required to aid the selection of suitable offshore aquaculture facilities and in the development of multiple use management plans.
This FRDC application, rather than focusing on cultural, economic and social elements of resource planning concentrates on the physical and biological data requirements. Many important cultural, economic and social issues have been identified in community and industry consultation by Fisheries WA during the development of the Aquaculture plan for the recherche Archipelago (Fisheries WA, 2000). The major outcome from these documents was that most other users of the Archipelago (Tourism, Shipping, Recreational and other commercial fishermen) indicated they were not happy with wholesale aquaculture development until accurate assessments of the benthic habitats and oceanography were completed over a wide spatial scale within the Archipelago. The recognition of this need has provided impetus resulting in aquaculture proponents (MG Kailis, Maritime Training Centre of Esperance), other fisheries (Esperance Professional Fishers Association, Esperance Professional Abalone Divers Association, 2 Recreational Angling Clubs), shipping concerns (Esperance Port Authority and industries utilising the port), tourism (Goldfields Esperance Development Commission), government departments (CALM, Fisheries WA, The Esperance Shire) and local concerned citizens (Recherche Action Group, Local Environmental Action Forum) all providing formal support for this application.
These groups see the need for representative broad scale bio-physical information to be used in the integrated planning to ensure the compatibility and sustainability of a diverse range of marine a coastal activities. This will ensure that the quality of the environment and the quality of life experienced by the populace living in Recherche Archipelago region is balanced with the need for new job creation in the region.
The 2.5 year research program we describe in this proposal will fulfil bio-physical data requirements for that planning process. This data will be available for incorporation into existing regional planning documents written in conjunction with cultural economic and social components that have been collected by Fisheries WA. It will also compliment and enhance information collected and developed by the Marine Group of the Department of Conservation and Land Management as part of the community and industry consultation involved in the MPA planning process.
Final report
This project is a joint Esperance community (through the Recherche Advisory Group - RAG), research scientist and resource management project. The commitment of RAG has allowed the researchers to efficiently transfer scientific information to the general public of Esperance and the South Coast of Western Australia and keep the research focused on management outcomes.
The outcomes of this report are:
- The design of a hierarchical classification scheme of benthic habitats in the Recherche Archipelago.
- An extensive habitat map of the Western Recherche Archipelago at both broad and functional habitat classifications and less detailed habitat maps of duke of Orleans Bay and Cape Arid to Middle Island.
- An oceanographic model of the influence of ocean swells on the Western Recherche Archipelago. This model includes an assessment of swell driven shear at the benthos.
- A broad scale fisheries-independent non-destructive survey of the demersal fish of the Recherche from Esperance Bay to Cape Arid. The survey was designed to capture habitat differences in fish assemblages.
- A broad scale (within the Western Archipelago) survey of the infauna found in a range of soft bottom habitats including coarse sands, rhodoliths and sparsely vegetated sands.
- Fine scale diversity surveys of reef communities on islands in the archipelago from Figure of Eight to Middle Island. These surveys integrate information from both habitat mapping and physical oceanographic modelling.
Keywords: habitat, classification, mapping, oceanography, benthic, algae, infauna, sessile invertebrate
Determining ecological effects of longline fishing in the Eastern Tuna and Billfish Fishery
The ET&BF is presently dealing separately with a number of ecological issues. For example, impacts of longliners on shearwaters and turtles are current high profile problems. However, other issues such as depletion of swordfish, SBT bycatch, availability of tunas in relation to oceanographic features, bycatch of sharks and finning have all taken centre stage at different times in the short history of the domestic fishery. This approach is often reactionary, rather than strategic, and may not be the best use of research resources over the long-term. If the ET&BF is to move substantially toward ecosystem-based fishery management, as it is required to do under the EPBC act, rather than continue the individual species management approach, an ecosystem analysis providing ecosystem metrics must be developed. If, for example, ET&BF managers opt for time area closures as part of their management strategy to protect key species, developing these on a species-by-species basis has the potential to impact the whole fishery. To develop and evaluate time area closures that allow for minimizing risk of adverse impacts to the suite of key species, while allowing for optimal efficiency of fishing, understanding the associations, linkages and interactions between species is essential. This is the ecosystem approach. Developing an understanding of how ecosystem-associations relate to oceanographic features is also essential in open ocean systems where the dominant influence on distribution and local abundance is oceanography. The approach we are taking will provide the information needed to support an ecosystem-based management framework. Through the analyses we are proposing we will identify regional “hot spots”, detail their linkages and provide detailed scenarios as to how we think different management strategies and fishing practices will or will not impact pelagic food chains, ecologically related non-target species, competitors (e.g. sharks, marlins etc.) and their associated ecosystems. The need for ecosystem-based fishery management for the Western Pacific region has also been supported by PrepCon for the soon-to-be formed WCPFC (Working Paper 9, 2002).
Final report
Seafood CRC: Clean Seas Tuna - Product Quality Issues (maturation and harvest stress)
Seafood CRC: genetic selection for Amoebic Gill Disease (AGD) resilience in the Tasmanian Atlantic salmon (Salmo salar) breeding program
Tactical Research Fund: Adapting to change - minimising uncertainty about the effects of rapidly-changing environmental conditions on the Queensland Coral Reef Fin Fish Fishery
TC Hamish (Category 5) traversed the southern Great Barrier Reef (GBR) in early March 2009, surpassing all previous storms in intensity, duration and maximum track length over reef structure. Hamish neatly bisected the major line fishing grounds of the Coral Reef Fin Fish Fishery (CRFFF), crossing the GBR east of Bowen then drifting southeast through the GBR southern section. The section of the GBR affected historically produces 70% of the annual landings taken by the commercial fleet as well as supports significant charter businesses and recreational fishing opportunities.
Commercial fishers were first to witness structural damage caused by TC Hamish with many reefs reported as receiving extreme damage (loss of live coral). Swift response by AIMS long term monitoring confirmed these reports showing some Mackay reefs suffering reductions from >75% to 10% live coral cover.
TC Hamish may have also caused marked decreases in Sea Surface Temperature (SST) similar to TC Justin (March 1997). TC Justin was a long-lived (24 days) system with an unusually large cloud mass, which cooled SST by 40C. Anecdotally, the unseasonal water cooling depressed CPUE of coral trout, and was responsible for an anomalous northward shift in the distribution of red throat emperor.
Within two weeks of Cyclone Hamish, the commercial CRFFF fleet began adapting to the poor fishing and low CPUE in southern GBR waters, with some vessels relocating to northern unaffected fishing grounds (thereby causing potential indirect consequences for northern fishers) and others choosing to remain “tied-up” to the wharf.
A significant threat of global climate change is that the frequency of intense storms may increase. Investigating the effects of extreme weather events on fishing and associated industries is a high priority. The need also extends to exploring the adaptive ability of all stakeholder groups in circumventing the negative impacts of such events.
Final report
With the severity and intensity of tropical cyclones predicted to increase with global climate change (Webster et al. 2005), the need to understand the effects of these events on fisheries production is paramount. The northern tropical margin of the Australian continent is subject to tropical cyclone influence each monsoon season. Although the increased rainfall that accompanies these events may have positive benefits for some fisheries production (e.g. Halliday et al. 2008; Staunton-Smith et al. 2004), the influence of the many other biophysical changes that accompany tropical cyclones (eg: habitat alteration and water temperature fluctuations) is less certain. One fishery for which anecdote reports negative influences of tropical cyclone impact is the Queensland Coral Reef Fin Fish Fishery (CRFFF). Prior to the impacts of severe TC Hamish in March 2009, popular anecdote reported that the influence of TC Justin (March 1997) on catch rate of the primary target species of the commercial sector, common coral trout (Plectropomus leopardus), were particularly negative and long lasting (up to twelve months). Somewhat surprising, the depressed catch rate of trout was accompanied by a noticeable increase in catch rates of red throat emperor (the secondary target species of the CRFFF) that was acknowledged though not quantified by Leigh et al. (2006).
The influence of tropical cyclones on the performance of the CRFFF is an annual event, though mostly restricted to loss of potential fishing days due to the inclement and unpredictable weather that accompanies the monsoon season. The ‘average’ cyclone that impacts the Great Barrier Reef World Heritage Area (GBRWHA), within which the CRFFF operates, is generally short lived and crosses the reef structure rapidly in an east to west direction. With the last two decades, most tropical cyclones impacting the GBRWHA have been low intensity systems (category 1 or 2). The influence of these types of systems on reef structure (coral coverage and diversity) and associated small-bodied reef fish communities has been well documented (e.g. Wilson et al. 2009; Emslie et al. 2008). However, as the monitoring used for these reports focuses initially on corals and secondarily small-bodied fish communities, the ability to measure changes in large-bodied reef fish communities is either not attempted, or compromised. As such, no robust assessment has been completed to understand the changes in abundance and availability of CRFFF primary target species in response to cyclone impacts.
TC Hamish impacted the southern section of the GBRWHA in March 2009, and quickly galvanised fishers, managers (both fisheries and Marine Park) and research scientists with a common need to The project outputs clearly demonstrate catch rates within the CRFFF can be significantly and adversely affected by some cyclone events. Understanding the biophysical drivers of these changed catch rates is difficult due to the variable and unique nature of each cyclone event. However, it is clear from project outputs that the negative effects of a cyclone may significantly alter catch rates and that these effects may linger for at least twelve months post-event. The gradual dominance and reliance for economic viability of the commercial sector on live coral trout, has stifled pre-existing adaptive capacity. The infrastructure investments and fishing behaviours of fishers targeting live coral trout are not amenable to changing market places; an ability that may well offer some adaptive capacity to the commercial sector of the CRFFF. In contrast, recreational and charter fishing sectors with their diversified fishing and targeting practices are immune to cyclone influence.
A suggested pro forma for an action plan to track, adaptation plan and possibly mitigate the negative influences of future unique cyclone events is a draft proposal at this time, and will need to be strengthened based on the outcomes from two working groups formed during the last six months. Considerations for further research should include: (1) Identifying the most appropriate data recording system for the CRFFF that will allow timely interrogation of catch data that is not available currently; (2) Canvassing options for building adaptive capacity into a fishery that is currently highly vulnerable to change due to economic reliance on a single species destined for a single market place; and (3) Better understanding the possible drivers of the sustained changes in ecological behaviours of reef fish following cyclone passage.