Use of stable isotopes to trace feeding patterns in the seahorse Hippocampus guttulatus: ecological and rearing implications
Year: 2015
Type: dissertation
Abstract: The worldwide decrease of wild seahorse populations is attributed to habitat\ndegradation, incidental captures (by-catch) and overfishing for traditional medicines, curio\nand aquarium trades. A global conservation concern on the state of wild seahorse\npopulations resulted in the inclusion of all seahorse species in the International Union for\nthe Conservation of Nature (IUCN) Red List of Threatened Species in 1996. Additionally,\nseahorses were also listed in Appendix II of the Convention on International Trade in\nEndangered Species of Wild Fauna and Flora (CITES) in November 2002. Conservation and\nmanagement efforts are required to ensure seahorse population persistence in the wild,\nincluding captive breeding programmes as an alternative to the capture of wild individuals\nand research on seahorse life history traits for the improvement of the effectiveness of\nconservation programmes.\nThis PhD Thesis aimed to investigate the feeding patterns of one of the European\nseahorse species inhabiting in the Galician coast (NW Iberian Peninsula), the long-snouted\nseahorse Hippocampus guttulatus, whose wild populations have declined or disappeared in\nmany areas in the last decades. The research was based on rearings in captivity and ecology\napproaches, specifically evaluating food assimilation in the early development of juvenile\nseahorses and assessing the dietary composition of wild seahorses. Both approaches were\nexclusively based on the application of the stable isotope analysis, which represent an\nimportant tool in ecological and physiological research. Stable isotopes are natural tracers\nwidely used to determine nutrient assimilation and to reconstruct animal diets, among\nother applications. The method is based on the fact that stable isotopes are transferred\nfrom prey to predators in a predictable manner, that is, consumers incorporate the isotopic\ncomposition of the resources that they use. This Thesis represents the first attempt to\ninvestigate seahorse feeding issues using the stable isotopes approach. Increasing our\nknowledge on feeding aspects of this seahorse species would help to redefine their status\nand to (i) reduce the number of Data Deficient species on the IUCN Red List, (ii) optimise\nculture techniques, (iii) monitor population trends and (iv) guide future management and\nconservation actions.
Author: Sonia Valladares
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
SDG: Life below water
Open Access status: green
OpenAlex ID: W2767543645