Identifying critical foraging habitats of the green turtle (Chelonia mydas) along the Pacific coast of the Baja California peninsula, Mexico

1. The conservation of highly mobile and migratory species remains one of the most serious challenges to resource managers. 2. Intense mortality of immature green turtles has been identified at principal developmental-feeding habitats in Baja California, and is considered a great threat to the stability of the eastern Pacific population. Thus, coastal lagoons of the Baja California peninsula, such as Bahia Magdalena, have been identified as high priority areas for their protection. 3. Conservation efforts to date have focused on creating a sea turtle refuge in the northwestern part of the bay, but this area may not be sufficient for protecting all of the critical feeding areas used by green turtles. 4. The diet of green turtles was investigated through analysis of digestive tract contents from 24 green turtles that were drowned incidentally in fishing nets at feeding grounds in Bahia Magdalena and adjacent areas along the Pacific coast of the Baja California peninsula, Mexico. 5. Mean straight carapace length (SCL) differed significantly between localities: mean: 55.5 cm (range: 47.7-76.9 cm, n = 11) in Bahia Magdalena; mean: 67.7 cm (range: 49-87 cm, 11 = 11) in adjacent coastal waters. 6. Green turtle diet consisted largely of marine algae and seagrasses, but food items varied spatially. The red algae Gracilaria pacifica, Gracilariopsis lelnaneiformis and Hypea johnstonii were the most abundant diet items inside Bahia Magdalena, and the seagrass Phyllospadix torreyi was the most commonly ingested food in coastal areas outside of the bay. 7. Results indicate that green turtles utilize spatially distinct foraging habitats within this region. Therefore, it is recommended that any design of protected areas for sea turtles in Bahia Magdalena should consider a regional approach instead of a local approach, taking into account the most important feeding areas used by green turtles at different life stages. Copyright (c) 2005 John Wiley & Sons, Ltd.