Spatial Ecology and Response to Catch-and-Release of Recreationally Targeted Fish Species on St. François and Alphonse Atolls

Alphonse Atolls (AA) and St. François (STF) are legendary among fly anglers. Recreational fishers from around the world travel to these remote locations to target species such as bonefish (Albula glossodonta), Indo-Pacific permit (Trachinotus blochii), milkfish (Chanos chanos), and giant trevally (Caranx ignobilis).

The Alphonse Fishing Company, which runs fly-fishing ecotourism in the two areas, worked with the Island Conservation Society and Islands Development Company (IDC) to analyse the impacts of fly-fishing on mainstay target species such as the giant trevally (GT).

The project assesses the responses of GT to angling stress both during and outside of fly-angling seasons. This involves conducting reflex impairment tests to gauge the species’ survival capability and monitoring the levels of blood glucose and lactate, which tend to increase with rising stress levels. The project also tracks GT’s movements to observe whether they disperse and use other parts of the atoll or remain near their capture.