Raphael M. Macieira

Fish Biodiversity of the Vitória-Trindade Seamount Chain, Southwestern Atlantic: An Updated Database

Despite a strong increase in research on seamounts and oceanic islands ecology and biogeography, many basic aspects of their biodiversity are still unknown. In the southwestern Atlantic, the Vitória-Trindade Seamount Chain (VTC) extends ca. 1,200 km offshore the Brazilian continental shelf, from the Vitória seamount to the oceanic islands of Trindade and Martin Vaz. For a long time, most of the biological information available regarded its islands. Our study presents and analyzes an extensive database on the VTC fish biodiversity, built on data compiled from literature and recent scientific expeditions that assessed both shallow to mesophotic environments. A total of 273 species were recorded, 211 of which occur on seamounts and 173 at the islands. New records for seamounts or islands include 191 reef fish species and 64 depth range extensions. The structure of fish assemblages was similar between islands and seamounts, not differing in species geographic distribution, trophic composition, or spawning strategies. Main differences were related to endemism, higher at the islands, and to the number of endangered species, higher at the seamounts. Since unregulated fishing activities are common in the region, and mining activities are expected to drastically increase in the near future (carbonates on seamount summits and metals on slopes), this unique biodiversity needs urgent attention and management.

Ambicoloration and morphological aberration in the sole Achirus declivis (Pleuronectiformes: Achiridae) and two other cases of color abnormalities in achirid soles from southeastern Brazil

Three cases of color abnormalities and one of morphological aberration in flatfishes of the genus Achirus are described from the Piraque-Acu River estuary, Espirito Santo, Brazil. One specimen of A. declivis has 75% of the blind side with coloration like that of the ocular side. Another specimen of the same species is strongly hypomelanistic. A third specimen has incomplete eye rotation and a hooked dorsal fin. An ambicolored A. lineatus is also described.

Island biogeography of marine organisms

Studies on the distribution and evolution of organisms on oceanic islands have advanced towards a dynamic perspective, where terrestrial endemicity results from island geographical aspects and geological history intertwined with sea-level fluctuations. Diversification on these islands may follow neutral models, decreasing over time as niches are filled, or disequilibrium states and progression rules, where richness and endemism rise with the age of the archipelago owing to the splitting of ancestral lineages (cladogenesis). However, marine organisms have received comparatively little scientific attention. Therefore, island and seamount evolutionary processes in the aquatic environment remain unclear. Here we analyse the evolutionary history of reef fishes that are endemic to a volcanic ridge of seamounts and islands to understand their relations to island evolution and sea-level fluctuations. We also test how this evolutionary history fits island biogeography theory. We found that most endemic species have evolved recently (Pleistocene epoch), during a period of recurrent sea-level changes and intermittent connectivity caused by repeated aerial exposure of seamounts, a finding that is consistent with an ephemeral ecological speciation process. Similar to findings for terrestrial biodiversity, our data suggest that the marine speciation rate on islands is negatively correlated with immigration rate. However, because marine species disperse better than terrestrial species, most niches are filled by immigration: speciation increases with the random accumulation of species with low dispersal ability, with few opportunities for in situ cladogenesis and adaptive radiation. Moreover, we confirm that sea-level fluctuations and seamount location play a critical role in marine evolution, mainly by intermittently providing stepping stones for island colonization.

The shore fishes of the Trindade–Martin Vaz insular complex: an update

A compilation of historical and recent collections and observations of shore fishes yielded 154 recorded species for Trindade and 67 for Martin Vaz. Twelve taxa, mostly small cryptobenthic species with limited dispersal capabilities and low ecological amplitude, are endemic to this insular complex. In several cases, the seamounts of the Vitória-Trindade Chain appear to have acted as stepping stones between the mainland and islands in periods of low sea level.

First record of partial melanism in the coney Cephalopholis fulva (Perciformes: Epinephelidae)

raphaelmacieira@hotmail.com Many abnormalities in the coloration of fishes have been recorded, including albinism, melanism and ambicoloration (e.g . DAHLBERG, 1970). Melanism, according to Gould and Pyle (1896), is characterized by the presence of an excessive amount of pigment in tissues and skin. In fishes, melanism may occur in varying degrees of intensity (PIGG, 1998) and can, in some cases, result from injury (DAHLBERG, 1970), genetic inheritance (HORTH, 2006), intergeneric hybridization (ELWIN, 1957) or parasite infestation (HSIAO, 1941). The coney Cephalopholis fulva (Linnaeus, 1758) is distributed in the Western Atlantic from South Carolina, USA, to Southeastern Brazil (FIGUEIREDO; MENEZES, 1980). As its Northwestern Atlantic and Caribbean counterparts, the Brazilian coney presents three color phases. The red phase is found in deep water individuals, the uniformly brown or bicolored phase (in which the upper half of the body is dark brown and the lower half creamy white) is mostly encountered in shallow water individuals and the xanthic phase (actually a morph rather than a phase) is found independently of depth (SMITH, 1971). This author suspected that the yellow variety is actually the result of a single gene, but no further information exists on this subject. The species exhibits diel changes in the pattern of coloration and the alternation between the fully brown pattern in daytime and the bicolored pattern at night has been fully documented (NEMTZOV et al., 1993). This present study describes the first recorded occurrence (DAWSON, 1964, 1966, 1971) of partial melanism in the coney. The specimen was captured about 10 km off the coast of Guarapari, Espirito Santo, Southeastern Brazil, near Rasas and Escalvada islands (20o42’07,8”S e 40o23’36,8”W), during hook and line samplings undertaken at quarterly intervals between July 2005 and October 2007. The substrate is formed of a mosaic of calcareous algae beds, rocky and biogenic reefs and extensive deposits of unconsolidated sediments, at depths varying from 15 to 33 m. An additional 147 coneys were captured during sampling. None, however, presented any type of coloration abnormality. The frequency of occurrence of the anomaly was therefore estimated to be 0.68 %. The specimen was photographed still fresh (Fig. 1a) and maintained frozen until fixation in 10 % formaldehyde and preservation in 70 % ethanol. The area of the melanic part of the body was estimated from a digital photography of the right side of the fish (Fig. 1a). A 1300-square grid was digitally overlaid onto the photography to determine the proportion of squares over melanic skin. As both sides displayed the some pattern and extent of melanosis, there was no need for measuring the area on the left side, and the result obtained for the right side was extrapolated for the whole body. The specimen is deposited in the fish collection of the Universidade Federal do Espirito Santo (CIUFES 0219). The anomalous specimen is an individual of medium size (223 mm total length; 186 mm standard length) and apparently healthy. The melanic portion is restricted to the posterior half of the body, beginning at a vertical under the last spine of the dorsal fin and extending to the end of the tail. This corresponds to 37.7 % of the corporal surface area (fins included). The excess of melanin was limited to the epidermis over the posterior extremity of body scales and over the whole scales and naked skin on the fins. The intensity of the pigmentation of the melanic area is greater on the dorsal and caudal fins, merging into a blander tonality in the lateral region of the body. The two small black spots on the top of the caudal peduncle, usual in this species (HEEMSTRA; RANDALL, 1993), cannot be seen due to the strong pigmentation in this region. The remainder of the body displays the normal coloration of an individual in the red phase (HEEMSTRA; RANDALL, 1993). In particular, the small dark-edged pale blue spots over the whole body (observed in the fresh organism (Fig. 1a) but that turned entirely dark after fixation (Fig. 1b) and the two small black spots on the tip of the lower jaw (one on each side), characteristic of the species, are present.

Status of Gobiosoma (Teleostei: Gobiidae) from Brazil: description of a new species, redescription of G. hemigymnum , molecular phylogeny of the genus, and key to Atlantic species

It is unclear how many species of Gobiosoma occur in Brazil and what their geographic distributions are. Here we combine data from a comprehensive morphological survey and a molecular analysis to clarify this uncertain taxonomy and place Brazilian Gobiosoma within a phylogenetic framework. Recent collections in Brazil, from the states of Ceará to Santa Catarina, and in Uruguay yielded two allopatric species of Gobiosoma that are distinct in genetics, meristics, morphometrics, scale pattern and coloration. Comparisons were made with types and specimens of Gobiosoma hemigymnum, Garmannia mediocricula, Gobiosoma spilotum and Gobiosoma parri and all other known species of Gobiosoma. We place G. parri in synonomy with G. hemigymnum with a distribution of Rio de Janeiro to Uruguay and Argentina. The northern species, that extends from the states of Espírito Santo to Ceará, is described as a new species, Gobiosoma alfiei. A key to the Atlantic species of Gobiosoma is provided.

Geographic expansion of the invasive mud sleeper Butis koilomatodon (Perciformes: Eleotridae) in the western Atlantic Ocean

The Indo-Pacific mud sleeper Butis koilomatodon (Eleotridae) is recorded for the first time in the south-western Atlantic Ocean, based on 23 specimens caught at seven localities along the northern, north-eastern, eastern and south-eastern Brazilian coast. The occurrence of males and females in different ontogenetic stages indicates that this exotic mud sleeper breeds there. This invasive species has the potential to compete for food and microhabitat with several native gobies and an endemic blenny that dwell in estuaries and mangroves, besides preying on native fishes and crustaceans.

Fringe on the brink: Intertidal reefs at risk

The rocky areas between low and high tide, known as intertidal reef habitats, are one of the most at-risk marine ecosystems ([ 1 ][1], [ 2 ][2]) as a result of coastal urbanization, sewage, and fisheries ([ 2 ][2]). Although they provide essential ecological services to society, such as shoreline

Endemic fish species structuring oceanic intertidal reef assemblages

Intertidal reef environments are facing a global crisis as climate changes are causing sea-level rise. Synergistically, other human-induced impacts (e.g., sewage, habitat loss) caused by concentration of human populations near the coast increase the natural vulnerability of intertidal ecosystems. However, the effect of these threats have long been neglected due, in part, to a limited knowledge of some aspects of intertidal fish ecology. We tested what are the main differences and drivers in fish assemblages structure between tidepools in three oceanic and three continental shelf (coastal) sites of the tropical southwestern Atlantic (Brazilian Province) using standardized sampling methods. Oceanic and coastal fish assemblages were distinctly structured at the trophic and composition levels. The noteworthy endemism species rate (38–44%) and high densities in oceanic sites are supported by resident species restricted to mid and high-shore tidepools where herbivores were the major trophic group. The coastal sites, on the other hand, were dominated by widely distributed and carnivore species. Physical (substrate type, pool height, subtidal distance and rock coverage), biological (sessile animal coverage) and chemical (salinity) parameters act as the driving forces influencing fish spatial occupancy. Here, clear evidences of high fish endemism and importance of endemics structuring oceanic communities may act as the last straw in favor of the conservation of oceanic intertidal reefs.