Marine scientists from James Cook University (JCU) in Australia have proposed that current go-slow zones in turtle habitats be extended to help safeguard the turtle population from boat strikes.
They arrived at this conclusion after tracking 18 green and 20 loggerhead turtles, concentrating mainly in the Moreton Bay area of Brisbane, where most strikes occur. Many of the shallow and all the deeper areas in the bay are not go-slow zones.
According to JCU’s Dr Takahiro Shimada, when the regulations came into effect, it was not possible to track the turtle habitats accurately. Hence, the study was conducted to find out where the turtles were located.
Based on the research, the turtles that were tracked could be found throughout the bay, and remained mostly in waters less than five metres deep.
"On the east side of the bay, most of their habitat is covered by go-slow zones, but almost none of their habitats in the rest of the bay are covered," said Dr Shimada.
The turtles ran the risk of boat collisions when they surfaced to breathe, rest or when they basked at or near the surface. Collisions were also possible when there is insufficient depth to allow a hull or motor to pass over them safely.
According to Dr Shimada, if all shallow zones in Moreton Bay were designated as go-slow zones, almost half or more of the turtle habitats could be protected.
"If we did that and added a small buffer zone from shallow water extending into deeper water, up to 95 percent of the habitat would be covered,” he added.
Dr Shimada was also mindful of the recreational and commercial use of Moreton Bay, saying, “Effective management for recovery of a population doesn't necessarily require the elimination of a particular source of mortality but rather that the mortality is low enough to allow the population to recover. Management agencies will need to balance the needs for reducing boat strikes with the use of the resource by the community.”