Outlook Online 2009

Great Barrier Reef Marine Park Authority :: Status of sharks and rays

Status of sharks and rays

Management Concern: High    

Adequacy of Information: Low

Summary extracts from Outlook Report 2009

  • While there is little detailed information about populations for most of the 134 species of sharks and rays recorded in the Great Barrier Reef, some species are known to have declined significantly.
  • Sharks and rays have come under serious pressure on the Great Barrier Reef as a result of some fishing practices, including targeted fishing, illegal fishing and as bycatch.
  • Pressures on shark populations are more serious than on other fishes because they are slower breeders and being top predators are less abundant than prey species.
  • The role of predation is still not fully known, but clearly there are links between predators and prey and flow on effects on habitats. Declines in some Great Barrier Reef predatory species, including some sharks, suggests that predation in Great Barrier Reef food webs may have been altered significantly.
  • Much of the research activity on the Great Barrier Reef is confined to areas surrounding the six island research stations. With ongoing management, any impacts of research are likely to be small and localised in the immediate area of study.
  • Increasing coastal development is resulting in the loss of both coastal habitats that support the Great Barrier Reef and connectivity between habitats.

What do we know?

Relevant pages from Outlook Online include:

Existing policies and management actions

Future management requirements

Defined research questions

Shark and ray biology

  • What are the main species of sharks and rays taken in Great Barrier Reef fisheries, and how can these be reliably identified by fishers?
  • What roles do sharks and rays play in the ecosystem functioning and resilience of the Great Barrier Reef, and what are the ecological consequences of reducing their populations?
  • What are the species of chondrichthyan fishes (sharks, rays, skates and chimeras) present in the Great Barrier Reef? What are the current status and trends of these species? What is the distribution and stock structure of these species? What are the life history characteristics and population dynamics of exploited shark and ray populations in the GBR?
  • How do changes to environmental conditions (eg. declining water quality, habitat degradation, climate change) affect sharks and rays?

Impacts, sustainability and management

  • What are the key threatening processes, their impacts, and the critical issues for the conservation of threatened elasmobranch species (eg. grey nurse shark, great white shark, whale shark, freshwater sawfish, green sawfish, speartooth) and for other high risk elasmobranch species in the Great Barrier Reef Marine Park? How can risks be reduced?
  • What impact do human activities (e.g. fishing, tourism) have on sharks and rays in the Great Barrier Reef?
  • What historical and baseline information is available about shark and ray populations in the Great Barrier Reef?  How does this compare with the current status?
  • What is the abundance of sharks and rays on the Great Barrier Reef?
  • What are the movement patterns and habitat use of sharks and rays in the Great Barrier Reef? How do these patterns of movement and habitat use relate to existing and potential management arrangements concerning sharks and rays? How do they inform research on status and abundance of sharks populations?
  • What are the sources and current total levels of mortality to shark and ray species in the Great Barrier Reef from natural and anthropogenic sources? What levels of mortality are sustainable?
  • What is the species composition of the sharks and rays in commercial and recreational fisheries in the Great Barrier Reef? What are the trends in fishing effort and levels of catch (or interaction rate) of individual shark and ray species these fisheries? What is the fate of sharks and rays caught in these fisheries (retained catch, non-retained by-catch, cryptic mortality)?
  • How can the level of mortality be decreased?
  • What is the risk to elasmobranch (sharks and rays) populations taken in commercial mesh net, line and recreational fisheries (including species and quantities taken)?

Human dimensions

  • What are community attitudes, perceptions and values (e.g. social, economic, cultural, ecological) towards shark and rays, including their use and conservation in the Great Barrier Reef?
  • What is the community’s level of awareness of the status and conservation issues relating to sharks and rays in the Great Barrier Reef? 
  • What are the current and projected social, economic and cultural factors that influence the take of sharks (e.g. market supply and demand, fear and loathing, competition for fish)?
  • What are the relative human values associated with sharks (eg economic value of a live shark to the tourism industry vs economic value of a dead shark to a fishery)?
  • What is the trade of shark products from the Great Barrier Reef, including shark fins,  imports, exports, market factors and domestic consumption?  Illegal fishing, illegal trade, reporting system, management effectiveness for catch reporting and finning?

Fisheries management and compliance

  • What are effects of marine park zoning on fish populations and fisheries (e.g. target species, prey species and indicator species)?
  • What is the current, overall state of knowledge on the status, management and impacts of fisheries (i.e. synthesis and integration of existing data and information)?

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