Reducing Prawn-Trawl Bycatch in Australia: an Overview and an Example from Queensland
Total Page：16
File Type：pdf, Size：1020Kb
Reducing Prawn-trawl Bycatch in Australia: An Overview and an Example from Queensland J. B. ROBINS, M. J. CAMPBELL, and J. G. MCGILVRAY Introduction sharks, and sea turtles. Bycatch varies zation of the impact of trawling on the spatially and seasonally in Australian ecosystem (Anonymous, 1998). Australian prawn-trawl fi sheries em - prawn-trawl fi sheries, with the ratio of The drowning of sea turtles in trawl ploy small-scale industrial fl eets rang- bycatch to prawns generally being low nets of northern Australia has been sug- ing from owner-operator vessels of 10 (3.5:1) in temperate-water fi sheries and gested to be the cause of the decline m in length to large company-based high (15:1) in tropical-water fi sheries of the nesting population of logger- fl eets with vessels up to 40 m in length. (Dredge, 1988; Harris and Poiner, 1990; head turtles, Caretta caretta, in eastern Fleet composition varies between fi sh- Andrew and Pepperell, 1992; Pender et Australia (Limpus and Reimer, 1994). eries. Otterboard trawling for prawns al., 1992; Carrick, 1997). Many bycatch It is estimated that a combined total and scallops occurs in the coastal waters species could be of commercial value, of about 11,000 sea turtles are caught of most states of Australia (Fig. 1). but the remoteness of the fi sheries, the annually in the northern prawn fi shery In Australia, bycatch is that part high cost of freezing and storing the and the Queensland east coast trawl of the catch that is not kept for mar- catch onboard, and the lack of orga- fi shery (Poiner et al., 1990; Robins, keting but is returned to the sea for nized markets for these species has led 1995; Poiner and Harris, 1996). Mor- economic, legal, or personal reasons. to high value-per-unit species becom- tality rates of trawl caught turtles are It may include fi sh, crustaceans, mol- ing the retained catch. estimated to be between 1% and 14%, lusks, echinoderms, sponges, stingrays, depending on the duration of the tows Australian Overview associated with particular locations The authors are with the Queensland Department Prawn-trawl fi sheries within Austra- within these fi sheries (Robins, 1995; of Primary Industries, Southern Fisheries Centre, lian waters are highly regulated com- Poiner and Harris, 1996). The main P.O. Box 76, Deception Bay, Queensland 4508, Australia. Corresponding author is J. B. Robins, pared with other countries, and all are species of sea turtle caught in Aus- email: [email protected] limited-entry fi sheries. Bycatch issues tralian prawn-trawl nets are fl atback in northern Australian prawn-trawl fi sh- turtles, Natator depressus; loggerhead eries focus predominantly on unwanted turtles; green turtles, Chelonia mydas; ABSTRACT —Prawn trawling occurs in most states of Australia in tropical, subtrop- fi sh bycatch and the incidental capture and olive ridley turtles, Lepidochelys ical, and temperate waters. Bycatch occurs and mortality of sea turtles in trawl nets olivacea. Of these, the loggerhead turtle to some degree in all Australian trawl fi sher- (Table 1). Bycatch issues in southern is listed as endangered at both state ies, and there is pressure to reduce the levels Australian prawn-trawl fi sheries focus and Commonwealth levels and is the of trawl fi shery bycatch. This paper gives predominantly on unwanted fi sh and focus of a national recovery plan a brief overview of the bycatch issues and technological solutions that have been eval- crustacean bycatch (Table 1). (Anonymous, 1999). Furthermore, the uated or adopted in Australian prawn-trawl There are several reasons why by- Commonwealth “Endangered Species fi sheries. Turtle excluder devices (TED’s) catch issues in Australian prawn-trawl Protection Act 1992” and the nomi- and bycatch reduction devices (BRD’s) are fi sheries have received considerable nation of trawling as a “key threaten- the principal solutions to bycatch in Aus- tralian prawn-trawl fi sheries. This paper attention over the past decade. Most ing process” has provided an additional focuses on a major prawn-trawl fi shery of Australian fi sheries management agen- means of pressuring the prawn trawl- northeastern Australia, and the results of cies have a legislative mandate to ensure ing industries of northern Australia to commercial use of TED’s and BRD’s in that trawl fi sheries comply with the mitigate their catch of endangered sea the Queensland east coast trawl fi shery principles of ecological sustainable turtles. are presented. New industry designs are described, and the status of TED and BRD development (ESD), such as the Com- The U.S. embargo of shrimp caught in adoption and regulation is summarized. The monwealth “Fisheries Management Act nets without TED’s created some addi- implementation of technological solutions 1991” and the Queensland “Fisheries tional pressure on Australian prawn fi sh- to reduce fi shery bycatch is assumed gener- Act 1994.” Many Australian prawn- eries to address their catch of sea turtles. ally to assist prawn-trawl fi sheries within Australia in achieving legislative require- trawl fi sheries also have legislation or However, most Australian prawn-trawl ments for minimal environmental impact policies that require a reduction in the fi sheries were not directly infl uenced by and ecological sustainable development. take of nontarget species and a minimi- the U.S. embargo, because the majority 46 Marine Fisheries Review Table 1.—Bycatch issues within Australian prawn-trawl fi sheries and the status of adoption of TED’s and BRD’s. Fishery Bycatch issues Key initiators Technological solutions Queensland east coast1 Sea turtles and fi sh, since the Conservation driven but Mandatory TED’s in 7 areas as of 1 May 1999; mandatory BRD’s in daytime late 1980’s supported by industry trawling by early 1999 Torres Strait Sea turtles, unwanted fi sh bycatch Conservation driven Voluntary use and testing of TED’s and BRD’s Northern Prawn Sea turtles, unwanted fi sh bycatch Conservation driven but Compulsory use of TED’s and BRD’s 1 April 2000 since the late 1980’s supported by industry Western Australia: Kimberley Jellyfi sh Industry driven Voluntary use of grids coast Western Australia: Fish, seaweed, and crabs Industry driven Voluntary grid and BRD trials Exmouth Gulf since 1996 Western Australia: Shark Bay1 Sea turtles and crabs since 1996 Industry driven TED and BRD research trials in progress South Australia: Spencer Gulf Crabs and fi sh since the mid 1980’s Industry driven Voluntary use of crab bags, mandatory areas closures, grid and BRD trials and West Coast South Australia: Gulf of Small prawns and fi sh since 1995 Industry driven Voluntary use of square-mesh codends at selected times St. Vincent New South Wales: estuaries Fish since late 1980’s Government driven, Voluntary use of BRD’s (Nordmore grid) at selected times and places supported by industry New South Wales: oceanic Fish since late 1980’s Government driven, Voluntary use of BRD’s (square-mesh panels) at selected times and places supported by industry 1 Fisheries either entirely or partially within a “World Heritage Area.” of Australian prawn catch is exported to Asia (ABARE, 1998). “World Heritage” status has brought increased scrutiny of commercial fi shing practices, especially trawling operations, to ensure that the exploitation of fi sher- ies resources do not occur at the expense of the quality of the ecosystem. Two Australian prawn-trawl fi sheries occur within “World Heritage Areas,” these being the Great Barrier Reef World Her- itage Area in Queensland, and the Shark Bay World Heritage Area in Western Australia. World Heritage status implies that the listed area has fi xed cultural and natural properties of such outstanding value, from a global perspective, that the site listed should be conserved and protected for the benefi t of all humanity (Valentine et al., 1997). Although the bycatch of unwanted fi sh has been an issue for a long time, pressure to reduce the capture of noncommercial Figure 1.—Trawl fi sheries of Australia for prawns and scallops (ABARE, 1998) species has increased recently. Reduc- ing fi shery bycatch had been addressed bycatch within the fi shery (Table 1). 1) were the fi rst Australian prawn-trawl primarily through the use of techno- For example, square-mesh panels are fi sheries to have legislative deadlines logical gear solutions, such as turtle voluntarily used during oceanic trawl- for the compulsory use of TED’s and excluder devices (TED’s) and bycatch ing in New South Wales for eastern BRD’s. In the Queensland east coast reduction devices (BRD’s). Additional king prawns, Penaeus plejebus, to allow trawl fi shery, TED’s and BRD’s are ways to reduce the overall bycatch of the escape of unwanted fi sh bycatch being phased-in over 2 years (Anony- prawn-trawl fi sheries have been achieved (Broadhurst and Kennelly, 1997), while mous, 1998), and legislation supporting through the reduction in the number of crab-bags and grids have been used in these requirements in the Queensland days fi shed or specifi cations of allowable Spencer Gulf, South Australia, to remove east coast trawl fi shery was gazetted fi shing gears (i.e. smaller nets). Many blue swimmer crabs, Portunus pelagi- in April 1999. TED’s were made com- TED’s and BRD’s are being used in var- cus, from the catch (Carrick, 1997). pulsory on 1 May 1999 in seven areas ious fi sheries, depending on the reason The Queensland east coast trawl fi sh- where the risk to sea turtles of trawl for reducing bycatch and the type of ery and the northern prawn fi shery (Fig. capture and drowning is appreciable. 61(3), 1999 47 A multiple-agency risk assessment pro- geographic area from lat.