Large marine protected areas (MPAs), each hundreds of thousands of square kilometers, have been set up by governments around the world over the last decade as part of efforts to reduce ocean biodiversity declines, yet their efficacy is hotly debated. The Chagos Archipelago MPA (640,000 km2) (Indian Ocean) lies at the heart of this debate. We conducted the first satellite tracking of a migratory species, the green turtle (Chelonia mydas), within the MPA and assessed the species’ use of protected versus unprotected areas.

Bycatch of endangered marine turtles is a growing issue for the management of all fisheries, including the oceanic purse-seine fishery. The aim of this study was to assess the spatial and temporal variation in bycatch rates of these species in the entire European purse-seine fishery operating in the Atlantic and Indian oceans. The study was based on data collected through observer programs from 1995 to 2011.

Hawksbill sea turtles (Eretmochelys imbricata) are listed as critically endangered by the International Union for Conservation of Nature (IUCN), with global populations demonstrating a decline of more than 80% over the past century (Troëng et al., 2005; Boden, 2008). Hawksbill sea turtles are one of the only vertebrate species that feed exclusively on sponges, relying on tropical coral reefs and their associated biodiversity for foraging grounds and shelter (Meylan, 1988; Eckert & Grobois, 2001).

We document and describe the change in attitudes, hunting behaviour and historic subsistence use of sea turtles by Cocos Malay people of Islamic faith in the Cocos (Keeling) Islands, Indian Ocean over the last 180 years. We used several lines of evidence including historical documents, scientific journals, archived records and interviews with current and former residents. The results are grouped in two time categories: 1) use of turtles prior to mid-1980s and 2) use of turtles after mid-1980s.

Many sea turtle species are threatened or endangered according to the IUCN Red List. Loggerhead turtles are protected in South African waters, but are migratory, thus may not be so throughout their range. Five individual turtles were caught in the beach-protecting nets off the Indian Ocean coast and provided liver and adipose samples for lipid and fatty acid analysis as part of a long term programme assessing the lipid profiles of southern Indian Ocean marine organisms.

While our understanding of the early oceanic developmental stage of sea turtles has improved markedly over recent decades, the spatial context for this life history stage remains unknown for Indian Ocean loggerhead turtle populations. To address this gap in our knowledge, 18 juvenile loggerheads were satellite tracked from Reunion Island (21.2°S, 55.3°E) between 2007 and 2011. Nine turtles swam north toward Oman (20.5°N, 58.8°E), where one of the world’s largest rookeries of loggerheads is located.

The Cocos (Keeling) Islands support high density resident green and hawksbill turtles and low to moderate density nesting green turtles. Dedicated studies were conducted on resident foraging turtles of the southern atoll between 1999 and 2012 and opportunistic observations were conducted on nesting turtles on both atolls between 1999 and 2009. In-water capture surveys resulted in a species composition of 51% green and 49% hawksbill turtles while counts during boat-based strip transect surveys resulted in a composition of 93% and 7% respectively.

Information on sea turtles is generally limited to breeding individuals and hatchlings monitored on nesting beaches. The life stages between hatchling and adult are difficult to observe and are referred to as the “lost years” (Carr et al. 1978). However, research regarding diet, population density and population viability has been conducted to better understand juvenile life stages (Maffucci et al. 2013; Witherington et al. 2012) and so, no more are those years as “lost” to knowledge as they were before.

Our summary has compiled available information about genetics of nesting and in-water sea turtle populations in the Indian Ocean and Southeast Asia so that others interested in this field of research might easily identify areas requiring further investigation. We have also identified studies with contradictory results that would benefit from additional investigation.