Testing the validity of using raceway and swimway performance in sea turtle hatchlings as an index of real-life crawling and swimming performance

Abstract

Abstract Context Increasingly, ecological studies of sea turtles are measuring locomotion performance of newly emerged hatchlings in raceways and swimways under the assumption that locomotion performance measured in these structures reflects locomotion performance in nature, and that such measurements reflect the chance of a hatchling surviving dispersion from their natal beach. Aims The aim was to test the assumption that an individual hatchling’s performance measured in artificial structures is correlated with the same individual’s performance in the natural environment (beach and sea), adding confidence that such measurements are an indirect indicator of dispersal ability during the first 24 h of post-nest life. Methods Green turtle (Chelonia mydas) hatchlings that had just emerged from their nest had their crawling and swimming speeds measured in an on-beach raceway and swimway. The same hatchlings then had their beach crawling and sea swimming speed measured and the correlation between their performance in the artificial structures and natural crawls and swims calculated. Key results An individual sea turtle hatchling’s locomotion performance in nature was correlated with its locomotion performance in raceways and swimways, but beach crawling was generally slower than raceway crawling, and sea swimming was generally faster than swimway swimming. We also found a weaker correlation between the raceway and beach crawling speeds than the sea and swimway swimming speeds. Conclusions The measurement of sea turtle hatchling crawling speed and swimming speed in artificial structures correlated with the individual’s locomotion performance in nature, supporting the assumption that the locomotion performance measured in artificial structures reflects their relative locomotion performance in the natural environment. Implications The measurement of sea turtle hatchlings locomotion performance in artificial structures can be used to indicate how variations in the nest microenvironment such as temperature and moisture affect a hatchling’s real-life locomotion performance, and thus reflect a hatchling’s dispersal ability during the first 24 h of post-nest life. Thus, sea turtle rookery managers can use this information to assess how their incubation management strategies affect hatchling locomotion performance, and consequently their likely offshore dispersal ability.