The research, led by Ana Sequeira at The University of Adelaide, found that rising sea temperatures may reduce the available habitat of whale sharks, and are likely to shift current whale shark populations towards the poles.
The researchers used sightings of whale sharks, recorded by tuna purse-seine fisheries, to assume the current global distribution. The data had been collected over different seasons and in some cases recorded whale shark sightings from over 30 years ago.
Currently, the range of the whale shark is commonly between 30-35°N. By combining this data with climate forecasts derived from global circulation models - which predict that existing sea surface temperatures will increase by at least 2°C on average by 2070 - the researchers discovered that the suitable range of the whale shark will be pushed towards the poles by 2070.
Perhaps more worryingly, the team predicted that the available suitable whale shark habitat will contract with rising sea temperatures. Ectothermic organisms, such as whale sharks, are sensitive to temperature change and rises in sea temperature lead to an increase in metabolic activity which raises food intake requirements. Other threats to whale sharks include illegal fishing, shipping activity and habitat disturbance.
The whale shark is listed as Vulnerable in the IUCN Red List (http://www.iucnredlist.org/details/19488/0) and the results of this research suggest that current management policies of whale sharks should be revised to attempt to guarantee the global survival of whale sharks.
Sequeira, A. M. M., Mellin, C., Fordham, D. A., Meekan, M. G. and Bradshaw, C. J. A. (2014), Predicting current and future global distributions of whale sharks. Global Change Biology, 20: 778–789. doi: 10.1111/gcb.12343
No comments:
Post a Comment