Fishing gear has the potential to affect marine wildlife both directly and indirectly. Fisheries in or adjacent to the Marine Park may catch marine mammals, turtles or other wildlife and the level of this by-catch may threaten some populations (for example, Queensland loggerhead turtles, dugongs, inshore dolphins). Fishing line or other gear discarded or lost by commercial and recreational fishermen can harm marine wildlife.

Actions

• In 2005 the Queensland Department of Primary Industries and Fisheries ran a workshop to determine potential education solutions to minimise the risk of capture, injury or death of protected species in fishing equipment. The Department has now prepared a guide for fishermen about looking after protected species
• An Endangered Species Awareness Course is available for commercial fishermen
• Intelligence-based and targeted surveillance and enforcement have been increased to prevent illegal fishing activities
• Internationally, in 2005 the United Nations Food and Agricultural Organisation provided guidelines to Reduce Sea Turtle Mortality in Fishing Operations.

Trawling

Trawling, in particular, was identified as a threat to marine turtles because turtles may be caught in trawl nets and may be submerged for an extended period of time, causing the animal to drown. Although turtles can dive for up to an hour, enforced submergence can deplete oxygen stores within 15 minutes and can disrupt physiological systems. In recent years, trawl fishermen and scientists have developed and introduced Turtle Excluder Devices (TEDs) in trawl nets to exclude turtles from the catch; their use is now mandatory under Queensland fisheries legislation. Turtle interaction becomes minimal if TEDs are correctly fitted and used.

Some marine turtles and dolphins are known to feed on fish discards from prawn trawlers, but there is no evidence that this adversely affects turtle populations.

How a By-catch reduction device works

The by-catch reduction device diagram depicts a trawl net with no by-catch reduction devices fitted. All animals that enter this net are caught in the cod end, including prawns, turtles and unwanted fish species. In the bottom diagram, the trawl net has two types of by-catch reduction devices fitted. The Turtle Excluder Device is a metal grid which stops turtles from entering the cod end by deflecting them through a flap on the trawl net. The second by-catch reduction device is a fisheye, which is an opening in the top of the net. Because fish have a tendency to swim against a current, the fish eye allows them to swim out through the top of the trawl net and avoid capture in the cod end. Even with the by-catch reduction devices fitted, prawns are still caught in the cod end as they are poor swimmers.

Actions

• The Queensland Fisheries Act 1994 requires the mandatory use of Turtle Excluder Devices, also known as TEDs, in Queensland. TEDs are one kind of by-catch reduction device (BRD) used to exclude turtles and other large marine animals (for example, sharks) from becoming trapped in trawl nets
• Information is provided to vessel crews about handling trawl-caught turtles so as to minimise mortality. All vessels are issued annually with these procedures along with their logbooks
• By-catch mitigation technology is continually refined and tested. If proven successful, the technical specifications under the East Coast Trawl Plan will be revised. Current by-catch reduction programmes, including the mandatory use of by-catch reduction devices (BRDs) in trawl nets will reduce discards available to marine wildlife.

Mesh netting

As air breathing animals, marine mammals and turtles can die when entangled in a fishing net. This may be due to their inability to reach the surface of the water to breathe or their reaction to the stress of entanglement, where in the case of dugongs, they block their airways to prevent the intake of water.

Commercial mesh netting has been identified as a significant cause of dugong mortality and marine turtles are also known to become entangled from time to time. Under Australian and Queensland Government legislation it is a requirement to report dugong and other marine mammal deaths in commercial fishing nets, however, there is concern that these deaths are not being reported. As such, aside from a few reports from responsible fishermen, there are repeated occurrences of dead dugongs, dolphins and marine turtles washed ashore in some areas, when seasonal availability of target fish species attracts increased net fishing effort.

Actions

• A network of 16 Dugong Protection Areas was established in 1998 in the Great Barrier Reef World Heritage Area and the Hervey Bay and Great Sandy Strait region
• The number of commercial mesh netters licensed to operate in the Great Barrier Reef Region has halved since 1997
• Significant additional protection from mesh netting has been provided under the Great Barrier Reef Marine Park Zoning Plan 2003, which increased the proportion of strictly protected zones in the Park from less than five per cent to over 33 per cent and increased the areas where mesh netting is prohibited by zoning from five per cent to greater than 38 per cent.

Pot fisheries

Negative interactions between crab fishermen with turtles have been recorded, and many turtles are accidentally entangled in crab pot ropes or drown inside pots.

Actions

• A reduction in crab pot opening size has been agreed through the Crab Fishery Management Advisory Committee to minimise turtle capture risk.

Queensland Shark Control Program

Marine mammals and turtles risk becoming entangled in mesh nets deployed as part of the Queensland Shark Control Program, operated by the Queensland Department of Primary Industries and Fisheries. Whilst very few marine mammals and turtles are now killed in shark nets in the Great Barrier Reef World Heritage Area, between 1962 and 1992, 837 dugongs were killed in shark nets and more than 4000 marine turtles were caught.

Actions

• The Shark Control Program has been reviewed in 1992, 1998 and 2006. A number of shark meshing nets have been replaced with drumlines
• The Great Barrier Reef Ministerial Council supports the replacement of shark nets with drumlines unless the nets are shown to be preferable for reasons of human safety 
• Today, most of the turtles caught in the program are released alive and changes in shark catching practices over the past decade have reduced the number of turtles being caught and killed
• Shark control contractors are provided with training to release live animals such as turtles taken by program gear, although the subsequent survival rates of the released turtles are not known
• Trials have been conducted on a modified hook design and different baits to minimise the risk of turtle capture
• Within the Great Barrier Reef World Heritage Area the program uses approximately 170 drumlines and ten nets. The numbers and net/drumline configuration used throughout the year varies; for example, the equipment in Cairns is removed for six weeks in January/February during the ‘marine stinger’ season when the contractor is on leave; and the net at Eimeo Beach, Mackay, is replaced by six drumlines from September to March to minimise the risk to turtles that nest on the beach.