Resource utilization and trophic position of puffer fish in different foraging grounds from a subtropical bay as revealed by stable isotopes

Mangroves are highly productive ecosystems presumed to provide nursery, breeding and feeding grounds for an array of fish species. In this study, we assessed resource utilization by S. testudineus and S. greeleyi in interconnected mangroves, saltmarshes and shallow subtidal channels from a subtropical bay. We hypothesized that if puffer fish migrate into mangroves mainly to feed rather than to find shelter, then their isotopic signatures will be closer to mangrove food sources than to those from adjacent habitats. We also tested the hypothesis that the coexistence of the two closely related puffer fish species may be explained by (i) food partition and (ii) preference for different foraging grounds. Our results emphasize the importance of saltmarsh food sources to the diet of both fish species. Puffer fish display a high trophic flexibility, feeding on the most abundant preys at each studied sites. Slight differences in carbon signatures and trophic levels of S. greeleyi and S. testudineus suggest food partitioning through the selection of differently sized prey items. Intraspecific competition in S. testudineus may result in trophic switch from saltmarsh to mangrove food sources. Our analysis emphasizes the importance of considering multiple habitats when investigating fish foraging grounds.

Promotor(s) & Supervisor: Paulo da Cunha Lana, Tom Moens

ISCED Categories

The highlighted icons, represent the fields of education (in compliance with ISCED Classification) engaged during this course/programme.

0511 - Biology", "0521 - Ecology