Huepel et al., 2008:

"Three data sets were examined to define the level of interaction of reef associated sharks with the commercial Coral Reef Fin Fish Fishery (CRFFF) within the Great Barrier Reef. Data were examined from; 1) fishery logbooks from 1989-2006; 2) an observer program within the fishery from 1996-1998; and 3) a fishery-independent survey, the Effects of Line Fishing (ELF) Experiment conducted from 1995-2005. The majority of the identified catch in the data sets was comprised of grey reef (62-72%), whitetip reef (16-29%) and blacktip reef (6-13%) sharks. Logbook data were inadequate for assessing the impact of the fishery on specific populations due to lack of species identification and sex or size data for landed sharks. In addition, no data were recorded in logbooks for hooked and released sharks. Logbook catch data revealed that reported landings of sharks were variable through time and across regions. Despite the observed variation, catch per unit effort was relatively stable through time and did not show any signs of increase or decline over the period for which data were available. The ongoing and consistent catches of reef sharks in the fishery may indicate that shark populations within the Great Barrier Reef Marine Park have remained relatively stable
during the last two decades, though population status relative to unexploited levels could not be estimated. Although the CRFFF has a large fleet of vessels, the majority of shark catch appears to be landed by a small number of vessels.

There were no significant differences in catch rates among regions from either the observer or ELF data sets. Catch rate estimates from both sources were in agreement, suggesting that they were representative of fishery activity and harvest. Data from the ELF Experiment also revealed that 2.2 times as many sharks were hooked but not successfully brought to the boat (encountered by the fishery) as were brought to the boat. Estimated encounter rates of reef sharks were between 1.34 and 2.48 sharks per dory day. This suggests that sharks were being encountered regularly and highlights the need to understand post-release survival. The ELF data set demonstrated that catch rates were higher in Marine National Park zones (no fishing) when compared to General Use zones open to fishing. This result suggests that no-take fishing zones provided at least partial refuge from fishing pressure for reef shark populations within the Great Barrier Reef.

Although these data provide insight into the recent history of reef shark encounters with the CRFFF there are limited useful data prior to 1995 (year the ELF Experiment commenced). Declines of shark populations from virgin levels are highly likely, although present data did not detect any recent decline. This analysis suggests that if declines occurred, they were prior to 1989 (first year of logbook analysis) and/or the rate of decline is not detectable given current harvest rates. Regardless, further study is required to better understand fishing mortality and the significance for reef shark populations. The analyses conducted here were based on studies focused on reef fish catch and were not directed at defining shark populations or encounters with the fishery. Research specifically designed to address the questions of shark presence, residence and abundance are required to fully understand these populations. Improved reporting in the fishery and continued management are also necessary for maintaining stocks and defining changes within populations targeted by the fishery."

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Citation and/or URL

Heupel, M.R., Williams, A.J., Welch, D., Mapstone, B.D., Ballagh, A. & Simpfendorfer, C.A. 2008, Compilation of information on the interaction of reef sharks with the reef line fishery in the Great Barrier Reef Marine Park: final report to the Great Barrier Reef Marine Park Authority. Research Publication (Great Barrier Reef Marine Park Authority) 92, Great Barrier Reef Marine Park Authority, Townsville, Australia.

Spatial Coverage

Northern, central and southern Great Barrier Reef. 

Temporal Coverage

 1995-2005

Update Frequency

Experiment finished in 2005 

Other Information

 None