Abstract

Otolith morphology has been used in trophic studies and in the identification of population and species. Otolith shape is species–specific with significant interspecific variability mainly due to otolith growth. Otolith growth and therefore otolith shape is affected by genetic and environmental factors, such as depth, water temperature and substrate type, and phylogenet-ic relationships. But, it is also linked to food, swimming, spatial niche, and producing sounds during courtship or defending the territory. It is known for some fish species that otolith shape may be a reflection of their adaptability to water depth and to different strategies of capturing prey. Groupers are top predators distributed in warm temperate and tropical ecosystems and associated with deep water and hard bottom reefs. Most of them compete with other groupers species for food in the same habitat, therefore developing specialized strategies. The objective of this study was to explore possible differences in groupers otolith shape according to the type of habitat and depth they live in. Otolith shape variation was analyzed in sagittae of sixteen grouper species belonging to four genera (Cephalopholis spp. (1); Epinephelus spp. (5); Hyporthodus spp. (4); and Mycteroperca spp. (6) from southern Gulf of Mexico. Taking into account their distinctive habitats and depths of occurrence, species were classified in: i) Reef-associated species in shallow depths (10 - 60 m): C. fulva, E. adscensionis, E. guttatus, E. striatus, M. bonaci, M. interstitialis, M. phenax, M. tigris and M. venenosa, ii) Soft bottoms and rocky ledges with 60 - 120 m depth: E. morio and M. microlepis, and iii) Deep water species (< 120- 600 m) with hard bottoms: E. drummondhayi, H. flavolimbatus, H. mystacinus, H. nigritus and H. niveatus.

PDF Preview