North-easternmost record of <i>Halosaurus ovenii</i> Actinopterygii: Notacanthiformes: Halosauridae) in the Mediterranean Sea, with notes on its biology

A single adult female specimen of Halosaurus ovenii Johnson, 1864 was captured by trammel nets at a depth of about 200 m off the coast of Arbatax (Sardinia, Italy) in early April 2007. Macroscopic and microscopic analysis of the gonad showed a postspawning ovary. This is the fourth documented capture of this fish in the Mediterranean Sea, representing the north-easternmost record for this species in this geographic area. Furthermore, the present specimen was fished at the shallowest depth ever recorded before

The Evolution of Fangs Across Ray-Finned Fishes (Actinopterygii)

To date, no study has investigated how many independent evolutions of fangs have occurred across ray-finned fishes. This research addresses this question by focusing on the evolution of fangs across a diversity of marine habitats in the Lizardfishes (Aulopiformes), and then investigating the evolution of fangs across ray-finned fishes (Actinopterygii). Lizardfishes are a diverse order of fishes (~236 species) that are observed to have fang-like teeth and occupy a variety of marine habitats. A taxonomic review of lizardfish specimens representing 35 of 44 genera were examined for the presence of fangs. In addition to assessing the presence of fangs, lizardfish habitat was also evaluated to examine if there is a correlation between fang presence and habitat. I estimated the character evolution of fang presence and habitat across a previously published phylogeny of lizardfish relationships to examine evolutionary patterns. I identified that fangs have independently evolved three times across the lizardfishes. There is also a correlation between the evolution of fangs in lizardfishes and habitat with fangs evolving more frequently in deep-sea pelagic habitats. To further investigate the evolution of fangs, I expanded my research to include a robust hypothesis of relationships among families of ray-finned fishes. Using previously published genetic data, I inferred a phylogeny of 315 species representing 211 families of ray-finned fishes. I again utilized ancestral character-state reconstructions to examine patterns of fang evolution across ray-finned fishes. The results of my analyses indicates that there have been at least 38 independent evolutions of fangs across ray-finned fishes. Generally in families that evolved fangs, when the majority of the species diversity possess fangs they are found in pelagic environments

Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size

THE MOST ABUNDANCE AND THE VERY RARE SPECIES IN THE DEEP SEA FISH COMMUNITY IN THE WESTERN SUMATERA, EASTERN INDIAN OCEAN

Variation in species abundance provides one of the striking phenomena observed in ecological communities. This variation has led ecologists to pose central questions pertaining to the nature of communities. Most of the deep sea regions provide the most widely habitat, but until recently information on its community is very little

Diversity of deep-sea fishes of the Easter Island Ecoregion

The Easter Island Ecoregion is in the center of the South Pacific gyre and experiences ultra-oligotrophic conditions that could make it highly susceptible to global change and anthropogenic activities, so it is imperative that these regions are characterized and studied so that conservation and sustainable management strategies can be developed. From the few studies from the region, we know that the coastal areas are relatively depauperate and have relatively high rates of endemism. Here, we present a brief report from the first video observations from this region of the deep-dwelling fishes from ROV exploration of benthic communities from 157 to 281 m and baited drop-camera videos from 150 to 1850 m. We observed a total of 55 fish species from the ROV and Drop-Cam surveys; nine could not be assigned family level or lower, 26 were observed in the ROV surveys, 29 were observed in the Drop-Cam surveys, nine were observed with both survey methods, at least six species are potentially new to science, and nine species were observed at deeper depths than previously reported. These new reports may be indicative of the unique oceanographic conditions in the area and the relative isolation of the communities that have provided opportunity for the evolution of new species and favorable conditions for range expansion. In contrast, these new reports may be indicative of the severe undersampling in the south Pacific at mesopelagic depths. The prevalence of potentially new species suggests that the region likely harbors a wealth of undiscovered biodiversity

Macro- and megafauna on the slopes of the Saya de Malha Bank of the Mascarene Plateau

A first characterization of the distribution and composition of benthic and demersal macro- and megafauna was derived based on video records sampled along five pre-determined transects up the slope on the western, northern and eastern sides of the Saya de Malha Bank on the Mascarene Plateau, starting at a maximum depth of 1000 m. Abundance was highest in the upper parts of eastern slope locations, primarily reflecting a relatively higher abundance of black corals (Antipatharia) than in other locations. A consistent feature of several transects, but most prominent in eastern and northern slopes, was the occurrence of patchy coral and sponge aggregations along the margin where the substrate was mostly hard. In some cases, these aggregations might be considered ‘gardens’ but reefs were not observed. Higher-level taxonomical composition of the fauna is presented. Demersal fish were widespread but not abundant, and within the depth range studied, there was a transition from a marginal shallow fish assemblage to a deepwater assemblage. Fishes were in most cases only assigned to family level, and 49 families were recorded. To thoroughly assess the biodiversity and abundance of fauna of the slopes of Saya de Malha Bank, further studies conducting more detailed video transects and sampling of specimens are warranted

Ictiofauna del banco de Galicia: composición taxonómica y aspectos biogeográficos

264 páginasEl objetivo general de esta tesis es determinar la composición faunística de peces que habitan el monte submarino del banco de Galicia y sus relaciones biogeográficas. Para ello se han planteado cinco objetivos específicos. 1. Listar las especies identificadas en el banco de Galicia, determinar la composición taxonómica y sus relaciones biogeográficas. 2. Determinar la composición de especies del género Apristurus (Pentanchidae) en el banco de Galicia. 3. Determinar la composición de especies de la familia Halosauridae (Notacanthiformes) en el banco de Galicia. 4. Determinar la composición de especies del género Lepidion (Moridae) en el banco de Galicia, sus relaciones interespecíficas y la descripción de hiperpigmentación melánica en ejemplares del género. 5. Determinar la composición de especies de la familia Bathygadidae (Gadiformes) en el banco de GaliciaLos estudios e investigaciones llevados a cabo en esta tesis doctoral forman parte del proyecto LIFE+ INDEMARESPeer reviewe

European Red List of Marine Fishes

The European Red List is a review of the conservation status of European species according to IUCN regional Red Listing guidelines. It identifies those species that are threatened with extinction at the regional level, so that appropriate conservation action can be taken to improve their status. This Red List publication summarises results for all described native European marine fishes.Postprin