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The Pacific Porgy (Calamus brachysomus) is a commercially important fish in Baja California Sur, Mexico, where it reproduces year-round. The feeding habits of fishes can change during reproductive stages in response to changes in energetic demand. The objective of this study was to characterize the trophic habits of the Pacific Porgy and how these varied by sex, reproductive stage, and season. Monthly samples were obtained from July 2015 to July 2016 in the central Gulf of California. The stomach contents of 235 specimens (108 males and 127 females) were analyzed. The trophic spectrum comprised 90 prey items, including 58 mollusks, 14 echinoderms, 13 arthropods, 2 chordates, 1 annelid, 1 poriferan, and algal remains. According to the prey-specific index of relative importance (%PSIRI), the most important prey items were the bivalves Transennella spp. (7.24%), Argopecten spp. (6.94%), Anadara spp. (6.25%), Septifer zeteki (6.19%), and Tivela spp. (6.1%). The trophic spectrum varied significantly by season but not by sex or reproductive stage. There were no significant interactions between sex and season or sex and reproductive stage. According to the Levin index, C. brachysomus exhibited a narrow trophic niche (Bi = 0.31). Costello graphs indicated the dominance of a few species, with shifts in the relative abundance of prey species. Based on the trophic analysis, C. brachysomus was classified as a tertiary consumer (3.18). Therefore, C. brachysomus represents an important link between upper and lower trophic levels. Based on these results, we inferred that the Pacific Porgy is an opportunistic predator that feeds actively during all reproductive stages. Thus, the energetic requirements needed for reproduction appear to be covered by the prey that comprise the trophic spectrum of C. brachysomus without this species needing to switch to more energy-rich prey. [ABSTRACT FROM AUTHOR]

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The fish community associated with a fringing reef was studied at Cautaro, Mochima National Park, Venezuela. A systematic sampling design based on visual censuses was carried out from December 2000 to May 2002. A total of 86 species belonging to 31 families were identified, dominated by Scaridae (10), Haemulidae and Labridae (9), Pomacentridae (7) and Serranidae (6), which accumulated, together with the sole species of Sparidae, 77.52% of the total abundance. Diplodus argenteus (13.15%), Microspathodon chrysurus (13.00%) and Thalassoma bifasciatum (10.79%) were the most abundant and frequent (>50%) species, and can therefore be considered typical and characteristic of the study area. The total diversity was 4.54 bits ind-1 and oscillated between 3.33 and 4.25 bits ind-1, with an average of 3.86. Equitability varied between 0.74 and 0.89. The relationship between species abundance and rank was significant (r = 0.976) and the diversity index of the log-series based on the number of species was α = 14.19. The trophic analysis of the community indicated that the carnivorous species constituted the dominant group (63.10%), followed by the herbivores (21.40%) and omnivores (15.50%). The normal distribution fitted the species abundance data, indicating a tendency towards stabilization in relation to the number of species. [ABSTRACT FROM AUTHOR]

Presents a study that examined age and growth of the annular seabream Diplodus annularis off the Canary Islands. Length range of the fish; Number of growth rings; Relation of seasonal growth cycles to physiological changes produced by the influence of temperature and reproductive cycle.