QFMA Research Priorities:
This project will address the following QFMA research priorities (relevant objective in parentheses):
Stock Assessment:
Determine the size and distribution of the stock of red throat emperor Lethrinus miniatus ** (I).
Assess regional catch rates of red throat emperor Lethrinus miniatus ** (I).
Determine the habitat preferences of juvenile red throat emperor Lethrinus miniatus ** (IV).
Biology:
Basic biology of red throat emperor Lethrinus miniatus and maori wrasse Chelinus undulatus** (I, II & III).
Management:
Identify appropriate units or indices on which to measure performance of stocks and the fisheries based on these stocks. *** (IV).
Determine the spawning period for major species other than coral trout Plectropomus leopardus and the red throat emperor Lethrinus miniatus **(III, this objective includes research on the reproduction of red throat emperor and coral trout also).
GBRMPA information requirements:
This project will address both immediate and strategic research priorities of the GBRMPA.
There is very limited information available on the effects of fishing on target species of the reef line fishery, other than P.leopardus, even though some may be more susceptible to overfishing. This project will provide information on population dynamics of the four reef fish species (L.miniatus, C.undulatus, C.altivelis and P.laevis) most likely to be impacted by reef line fishing. The need for this information has become more urgent given the recent and rapid development of the "live food fish trade" in the GBRR, and the high value placed on the maori wrasse and barramundi cod. There is considerable public and international concern to ensure that the capture of these species does not compromise the conservation and World Heritage Values of the GBR.
The GBRMPA is presently developing a system of " representative areas". The primary objective of these areas will be to protect a broad range of habitat types and reef communities from extractive use, including fishing, and conserve regional marine biodiversity within the GBRMP. Knowledge of the connectivity (larval and adult dispersal) among populations will be fundamental to the design of an effective system of representative areas. The extent of dispersal among regions will influence the number, size and location of representative areas required to ensure regional variation in reef communities are effectively conserved in the long-term. This project, if successful, will provide this information for L.miniatus, and the technical basis to extend the approach to other species of reef fish.
This project will provide priority information for red throat emperor, maori wrasse, barramundi cod and the common and blue-spot coral trout which will directly address immediate and long-term information requirements for the management of fishing on the GBR.
In doing so it will:
i) Through the application of genetic and otolith microchemistry techniques, provide information on the stock structure of L.miniatus within the GBRR and the technical basis to extend these approaches to other species. Evidence of the existence of regional structure (multiple stocks) in GBR will have direct and substantial implications for future management of fishing in the GBRR (ie Should a particular management tool be applied uniformly over the entire GBRR, or to separate management units?).
ii)By focussing on species from three important families of reef fish (serranids (barramundi cod and coral trout), lethrinids (red throat emperor) and labrids (maori wrasse)) it will provide the empirical and conceptual basis required to develop age-based multi-species population dynamics models for tropical fish stocks.
iii) Maximise the R&D benefits obtained from the substantial logistic support and expertise currently available through the ELF Project, and the ELF Experiment in particular. The coordinated logistics and focussed collaboration provide a rare opportunity to obtain a cohesive set of information for a complex multi-species system at a scale appropriate to its management. This project will add a substantial dimension to the outcomes of the ELF Project by providing data on population dynamics of several high priority target species and essential information on the stock structure of L.miniatus.
Final report
The Great Barrier Reef Marine Park (GBRMP) is the largest and, arguably, most pristine marine park in the world. Commercial, charter and recreational fishing have occurred on the Great Barrier Reef (GBR) for many decades. Since the late 1980’s, there has been growing concern about the sustainability of fishing on the GBR and the potential for it to have impacts on the broader ecosystem.
The Queensland Coral Reef Fin Fish Fishery (CRFFF) is one of the larger fisheries operating within the GBRMP and includes significant commercial, charter and recreational sectors. The need to better understand the impacts of line fishing on the GBR and sustainable levels of fishing was identified during the early 1990’s and was followed by a series of pilot and methodological studies. The outcomes of these studies and continuing concern lead to the establishment of the Effects of Line Fishing (ELF) Project in 1994 within the CRC Reef Research Centre. The centrepiece of the ELF Project is the Effects of Line Fishing Experiment and Management Strategy Evaluation (MSE) project (FRDC 97-124). The ELF Experiment involves monitoring the response of target and non-target species to changes in fishing pressure on six reefs in each of four regions of the GBR by manipulating the amount of fishing pressure on individual reefs within each region. The outcomes of the first two phases of the ELF Experiment (1995-2000) and the first round of management strategy evaluations are reported in Mapstone et al. (2004).
Outputs from this project have been used directly in the development of new management arrangements and regulatory measures for the Coral Reef Fin Fish Fishery and planning for activities within the Great Barrier Reef Marine Park.
In the case of the red throat emperor, the project has also provided validated age and length based estimates of key population parameters, and the regional variation in them, as a basis for developing quantitative stock assessment models for quota setting. The significant regional variation in some parameters identified through this project may require these models to be spatially structured.
This project, in conjunction with other elements of the ELF project, provided support for six PhD projects, and thereby made a contribution to increasing the number of well trained fisheries professionals available.
Keywords: red throat emperor, coral trout, blue-spot trout, barramundi cod, maori wrasse, Great Barrier Reef, fisheries management, population biology, reproductive biology, stock structure, genetics, otolith microchemistry, regional variation, age, growth, mortality, abundance
