Sea turtle populations in Sabah have been depleted through long-term harvests of eggs and adults, and as by-catch in the ever-growing trawl fisheries. In Malaysia, turtles are regularly caught shrimp trawls, and are collected for food and for illegal overseas markets. Targeted conservation is urgently needed. Because sea turtles are indicators of the health of various and diverse marine ecosystems, it is important to have a clear understanding of their population health, not only as nesting females on beaches, but throughout their life history.
But understanding the complex interrelationships between habitats and life stage development in sea turtles requires an understanding of several demographic (life history) parameters such as recruitment, size and age at maturity, gender ratios, growth and sexual development rates, survivorship and nesting probabilities. The problem is that these studies require access to turtles at sea, which is difficult because of the wide geographic areas across which turtles disperse, the logistical constraints of working in the marine environment, and the varied habitats they occupy at discrete phases of their lives.
For conservation to be truly successful, sea turtles need to be protected throughout their life cycle, rather than just those animals that we find on nesting beaches. In reality, sea turtles spend only small portions of their lives on nesting beaches: adult females spend a few hours laying eggs, the eggs develop in about two months and then emergent hatchlings cross the beach in minutes – a small proportion of lives that generally span upwards of five decades. Much greater conservation efforts are required in development and foraging habitats, focusing on these non-nesting life-stages. This necessitates understanding the temporal use and purpose of these marine habitats.
The general life-cycle of marine turtles is similar among species, but even given the amount of knowledge we presently have about sea turtles, there are some crucial gaps that have the potential to undermine management efforts. Among these is the knowledge of how many turtles join the breeding population in any given year, the period between onshore migration of juveniles to adulthood, and natural sex ratios in the wild. Lack of a clear understanding of any of these can have an effect on how turtle population data is interpreted and how this results in conservation action.
For instance, if no new females join a particular breeding population, after some protracted time period the extant females would be lost through various forms of mortality, and eventually no new nesting would occur and the population would be forever lost. While it is easy to count how many baby turtles leave a nesting beach, and how many adults return to nest, it is often unknown what happens in the time periods in between, and these periods often last some 25-30 years. Having an understanding of what happens in between, and knowing recruitment to adult breeding populations can help managers determine conservation needs.
At present, managers and conservationists have little knowledge of the rate of recruitment from juvenile into mature stages of the populations of sea turtles for any part of the globe, and only few sets of long term nesting data upon which to predict population behaviour. Frustratingly for biologists and managers attempting to influence how turtle populations will be affected by various natural and anthropogenic stresses, there is practically no way to determine what proportion new entrants to the breeding population represent, and whether there is a long-term decline in recruits or the reverse. These data are crucial and among the top priorities for researchers at present time, and this project would assist in providing the data sets to complement the long-standing history of research and data gathering from Sabah, and can be determined through the use of laparoscopy studies.
Laparoscopy is a form of surgery that uses a miniature telescope to directly view the inside of the peritoneal cavity. It is a potentially dangerous procedure and should not be attempted until proper veterinary training has been obtained. Laparoscopy can be used to determine the sex of immature turtles or the reproductive status of adults. The minimum equipment necessary is a laparoscope, trocar, sleeve, fiber optics projector and standard surgical instruments.
This work has been funded by various donors since its inception. We are grateful to the generous support by the Exxon-Mobil Foundation, the Western Pacific Regional Fisheries Management Council, Taiwan’s Bureau of Agriculture COA, the Save our Seas Foundation, and Sabah Ports Sdn. Bhd.
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