Tucker et al., 1995:

"Adult loggerhead females have been trawl-captured regularly near the Mon Repos rookery when in the internesting habitat (Limpus and Reimer 1994).  Ninety per cent of the dead loggerheads (n=69) recorded on the Bundaberg coast since 1984 were Mon Repos females carrying mature ovarian follicles and therefore killed during the internesting period (Limpus and Reimer 1994). Increases in nearshore trawling effort are consistently correlated with increases in incidental capture of loggerheads, particularly during the nesting season (Ruckdeschel and Zug 1982; Murphy and Hopkins-Murphy 1989; National Research Council 1990). For the WMP region, the highest potential for trawler-turtle interactions tends to be when seasonal rains flush prawns from estuaries into the nearshore zone.

The site fidelity that loggerheads exhibit for nesting beaches and to adjacent internesting habitat (Limpus 1985) may place them consistently in zones of higher trawler activity.  When encountering a net underwater, loggerheads do not swerve to avoid the net as do most other species, but will futilely attempt to outswim it (Ogren et al. 1977). While a short tow may not drown a turtle (Poiner et al. 1990), longer submersions or repeated captures can compound physiological stress on a turtle (Schwartz and Shoop 1992) and impair normal swimming function (Lutcavage and Lutz 1991). Weak or immobile turtles would probably be more susceptible to shark attack, boat strikes or further trawl captures.

We studied internesting habitat use by Loggerhead Turtles Caretta caretta with radio telemetry and by visual sightings of paint-marked turtles in Woongarra Marine Park, adjacent to the major mainland nesting rookery in Queensland.  A high concentration of females occurs within the Park during the early phase of the internesting period as ovulation and shelling of eggs occur.  From 36-72 hr following oviposition, activity ranges and swimming rates were greatly reduced.  About day 9 after oviposition, turtles resumed higher swimming rates and wider activity ranges and were as likely to be outside protected management zones as within.  Movements were generally within 10km north or south of the rookery, limited to 1-2km of the coast rather than offshore oriented and were independent of the currents.  Over 89% of the nesting females were susceptible to trawling at some time during their internesting period as they swam outside the Protected Management Area.  The likelihood of turtle-trawler interactions along the Woongarra coast and the potential of turtle excluder devices (TED's) as a conservation measure are discussed.  TED use provides a broadly applicable management option that can be combined with spatially or temporally restricted trawling zones.

Improvements in TED's have demonstrated that unintentional capture of turtles and bycatch can be minimised without significant reduction in prawn capture (Mounsey et al. 1992; Renaud et al. 1993). The tenfold reduction in turtle captures achieved by TED-equipped nets (Renaud et al. 1993) suggests that similar reductions could be expected for the Queensland trawling industry if TED's were widely adopted.  Recent testing of an Australian-designed TED that incorporates features of both hard and soft TED designs (Mounsey et al. 1995; Robins-Troeger et al. 1995) is an encouraging sign that actions to minimise bycatch are being considered within the Queensland trawling industry."  

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Citation and/or URL

Tucker, A. D., FitzSimmons, N.N., and Limpus, C.J. 1995,  Conservation implications of internesting habitat use by Loggerhead Turtles Caretta caretta in Woongarra Marine Park, Queensland, Australia.  Pacific Conservation Biology, 2; 157-166.   

Spatial Coverage

From Elliott Heads to the mouth of the Burnett River 

Temporal Coverage

1991 to 1992 

Update Frequency

Other Information

None