El caballito de mar Hipoccampus sp. en la Bahía de San Antonio (Patagonia): síntesis de los estudios realizados sobre la composición de la dieta y hábitos alimentarios

STORERO, LORENA P.; GONZÁLEZ, RAÚL

IBMP Serie Publicaciones

IBMP Alte. Storni / Universidad Nacional del Comahue

Lugar: San Antonio Oeste / Río Negro; Año: 2005 vol. 4 p. 45 - 65

1666-4019

The aim of this study was to evaluate the diet composition of the seahorse (Hippocampus sp.) in San Antonio Bay (Patagonia) through gut and stomach contents, and to assess the feeding behaviour in captivity with regard to prey selectivity by type and size, and time investment in activities related to searching and capture. This study was performed with samples collectedfrom two sites of San Antonio Bay. Type and number of preys in the digestive tracts were recorded and the frequency of occurrence (%FO) and number of preys (%N) were calculated for each study area. Experiments in aquaria were done with different diets composed by amphipods (Melita palmata, Ampithoe valida) and juvenile decapods (Chasmagnatusgranulata) from natural environment, and Artemia salina. Also, observations on time investmentin different activities and capture efficiency for each prey were done. The seahorse from San Antonio Bay preys mainly over amphipods (Gammaridae, Caprellidae and Hiperidae) and decapods (Brachiura and Caridea). Differences in %FO as well as in %N in the twostudy areas were observed. Such differences could be indicative of both the abundance and availability of preys in the environment. No diet differenceswere detected among sexes and sizes. In nature, due to the environmental factors, the seahorse behaves as an opportunistic predator, feeding on the most abundant and vulnerable prey. There were not significant differences in the quantity of prey ingested between males and females. In captivity, with optimal conditions for predation, seahorses prey selectively basing their preferences on size and shape of the prey. Behavioural observations and time investment show the seahorse as a highly efficient predator that bases its feeding strategy on the ambush of preys.