Many species of sea turtle have been declining over recent decades. Found throughout temperate and tropical areas, these animals are dependent on both marine and coastal habitats. Sea turtles are adapted to oceanic life, although they breathe air, but require suitable beaches for breeding. All seven sea turtle species are listed as endangered due to habitat changes, entanglement and bycatch in fishery equipment, and collisions with boats.

Sea turtle mortality has been tracked along the coast of the Baja peninsula of Mexico (BCS). For more than a decade, carcasses have been tallied to track population threats, along with observations on fishery vessels. The results to date have been published in Endangered Species Research. The most surprising - and sobering - finding concerns the past five years from 2003 to 2007, when nearly 3,000 sea turtles washed up along the survey area. Typically these were juvenile animals and represent only the fraction of actual deaths that resulted in stranding onshore.

The species being studied is the Pacific loggerhead sea turtle. These turtles migrate across the Pacific from Japanese breeding grounds to feeding areas off Baja California. They eat prey like whelks and other mollusks. Long-lived animals, loggerheads do not become reproductively active until about 35 years old. Once sexually mature, individuals return to their breeding grounds for the first time since hatching - travelling about 12,000 kilometres (7,500 miles). A single female can create 3-5 nests per season. However, nesting females have declined by 50-90% over the last decade.

The deaths are attributed to the effects of bycatch and poaching. The high rate makes the result one of the highest stranding and bycatch levels documented. Certain fishing equipment is associated with increased sea turtle mortality, including trawls, gillnets, longlines, traps, and pots.

While the mortality rate is staggering, it also offers new opportunities. Through fisherman education, it may be possible to cut bycatch drastically. In addition, concrete numbers can be used to approach government agencies about a marine refuge. Establishing conservation zones would offer habitat refugia for sea turtles and other species, as well as setting up a model for sustainable fishing.

Some marine areas have larger sea turtle populations and would benefit from protection. Many small-scale fisheries are receptive to conservation actions. Because local fishermen are dependent on continued fish availability, they often recognize the need to maintain a thriving habitat. Introducing viable alternative equipment and techniques, as well as pointing out less sensitive zones and species, can create sustainable options. Currently, sea turtles caught as bycatch are eaten (although other species, black and olive ridley turtles, are preferred).

Other economic possibilities can also promote stewardship of marine species. For example, conservation tourism might provide more stable revenue than struggling fisheries. Visitors are keen to see (and photograph) sea turtles in their natural environment. In addition, diving, snorkelling, and other lower impact activities can be positive options. With relevant training, former fishermen and poachers can become rangers and guides instead. For example, Ocean Conservancy offers a SEE Turtles program, while other organizations promote further opportunities. Because sea turtles are migratory across such long distances, multiple countries need to be involved in broad conservation and recovery plans.

Photo credit: Mil Clayton