Feeding Habits of Dwarf Goatfish (Upeneus parvus: Mullidae) on the Continental Shelf in the Gulf of Mexico

Feeding habits of dwarf goatfish on the continental shelf off Alvarado, Veracruz, Mexico, were analyzed to determine seasonal variation and size-class changes in diet composition and trophic overlap between size classes. Food was found in 63% of the 1,437 dwarf goatfish guts analyzed. The 52 dietary items identified consisted mainly of crustaceans, with Solenocera vioscai being the most important prey. Dwarf goatfish exhibited seasonal and size-class changes in prey consumption. Despite the high number of prey items, low values of diversity and diet breadth were found in the trophic spectrum. A high trophic overlap between size classes was observed in the north-winds season between length classes (92-111 vs 112-130 mm) (λ = 0.81) and (92-111 vs 131-150 mm) (λ = 0.80), and (112-131 vs 131-150 mm) (λ = 0.67). In the rainy season high overlaps were obtained between (92-111 vs 112-131 min) (λ = 0.73) and (112-131 vs 131-150 mm) (λ = 0.84) length classes. Dwarf goatfish appear to be opportunistic carnivorous predators that impact benthic and epibenthic invertebrates

Effect of habitat structure on the most frequent echinoderm species inhabiting coral reef communities at Isla Isabel National Park (Mexico)

The spatial distribution and abundance of the seven most abundant species of echinoderms (Diadema mexicanum, Centrostephanus coronatus, Eucidaris thouarsii, Isostichopus fuscus, Pharia pyramidatus, Phataria unifascialis and Acanthaster ellisii) were evaluated in coral communities of Isla Isabel National Park (Mexico). Biological (corals and other benthic groups) and physical (rocks and boulders) structural elements of the habitat were evaluated to determine their relationship to these species. Our results show that species composition and abundance varied among sampling sites and between seasons. Also were obtained significant differences in the echinoderm assemblage among sites across seasons. Similar results were detected for the environmental variables related to benthic habitat structure. D. mexicanum, P. unifascialis, E. thouarsii and C. coronatus were the main contributors to the species abundance and distribution in Isla Isabel. Most echinoderm species were positively related to the coverage of different coral species, algae and various types of benthic organisms as well as to physical benthic variables. These outcomes suggest that the spatial distribution and abundance of these echinoderms are explained by the habitat structure, which should be used to design conservation and management strategies for coral communities

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

La ictiofauna marina de Baja California Sur, México, desde la perspectiva de un trabajo museológico

One brief account and results of the generated activities through curatorial activities (fixing, preservation, taxonomy and catalogation) carried in the icthyological collection of the Centro Interdisciplinario de Ciencias Marinas are presented. This Icthyological stock carne from Baja California Sur; Concepción Bay (57 families and 146 species), La Paz Bay (84 families and 228 species), Magdalena Bay (65 families and 161 species), San Ignacio Lagoon (19 families and 29 species) and adjacent coasts of the Pacific ocean and Gulf of California (97 families and 244 species). There are however some specimens from other Mexican States and overseas México. This collection is important on a national level, and is the most complete for Mexican Pacific, accounting with 25000 organisms, integrated in 118 families, 270 genera and 403 species

Trophic spectrum of the california kingcroaker menticirrhus undulatus from ojo de liebre lagoon, baja california sur, mexico

A total of 112 stomach contents of the California kingcroaker Menticirrhus undulatus from Ojo de Liebre Lagoon, Baja California Sur (Mexico), were analyzed. The samples were taken from January to November 1995. This species occurred all year round, with highest abundance in July. The index of relative importance indicated that M. undulatus consumed a total of 14 species, and the dominant prey were polychaetes of the genus Marphysa spp. (51.75%), the fish Ilypnus gilberti (31.84%) and mollusk remains (13.91%). According to Levin's index, M. undulatus is considered a specialist predator, with preference for benthic fauna

Primer registro de Regalecus russellii (Shaw) (Pisces:Regalecidae ) de aguas mexicanas

Se describe un ejemplar joven de Regalecus russelli (Shaw) capturado en la Playa Tecolote, cerca de La Paz, Baja California Sur, el 16 de junio de 1985, y se presenta información sobre otros dos ejemplares de la misma especie que fueron vistos con anterioridad, uno en la localidad citada y el otro en Bahía de La Paz. Todo parece indicar que esta es la primera vez en que la especie se cita de aguas mexicana

Activity of the mexican purse seine fleet and the feeding habits of yellowfin tuna

Results of the analysis of information taken from fishing logbooks and samples obtained from the Mexican purse seine fleet are presented. This information was analyzed independently of the size of the ships and areas of operation. The study includes the time of beginning of sets and the time they were made, the relationship between the number of sets and the time they were made and the monthly variation in 1985. A comparison is made between this information and food volume of yellowfin tuna. It was found that the sets of yellowfin were made almost entirely during daylight hours as observed from the two modal intervals in nearly all the months analyzed; the first one occurs during the morning and the second one during the afternoon. The minimum of sets was registered between 11:00-13:00 hours; only in one case out of the 12 analyzed did the minimum occur between 13:00-14:00 hours (May). Various degrees of gastric depletion were observed throughout the day. However, at 13:00 and 14:00 hours the stomachs were nearly empty, forcing the tuna to look for food in deeper waters, because at this time of day light penetration is maximal, thus leading to a descent of the prey and lowering the vulnerability of the tuna to the fishing fleet. This, in turn, could account for the lesser number of sets at this hour of the day. The most important preys were: red crab (Pleuroncodes planipes), cephalopods Argonauta sp., Dosidicus gigac, Symplectoteuthis ovalaniensis and Onychoteuthis banksii) and the Pacific mackerel (Scomber japonicus)