Deep-sea anglerfishes (Lophiiformes: Ceratioidei) from off northeastern Brazil, with remarks on the ceratioids reported from the Brazilian Exclusive Economic Zone

The deep-sea anglerfishes of the suborder Ceratioidei (Lophiiformes) are represented by about 170 valid species with some of the most extraordinary morphological and reproductive adaptations among vertebrates, including extreme sexual dimorphism and male parasitism. Here we report on the diversity and distribution of rare ceratioids collected during the ABRACOS (Acoustics along the BRAzilian COaSt) expeditions off northeastern Brazil and the Fernando de Noronha Ridge (Rocas Atoll, Fernando de Noronha Archipelago, and associated seamounts). Chaenophryne ramifera, Oneirodes anisacanthus, O. carlsbergi, Gigantactis watermani, and unidentified specimens of Caulophryne, Dolopichthys, and Rhynchactis are recorded for the first time in the Brazilian Exclusive Economic Zone. Ceratias uranoscopus, Melanocetus johnsonii, and Chaenophryne draco have their distributions extended in Brazilian waters. Caulophryne, O. anisacanthus, and G. watermani are also recorded for the first time in the western South Atlantic. The specimen of G. watermani reported here represents the third known specimen of the species, and variations of its escal anatomy in relation to the holotype are described. Based on specimens examined and a review of records in the literature, 20 species of the Ceratioidei, in addition to unidentified species of Caulophryne, Dolopichthys, and Rhynchactis, are confirmed in the Brazilian Exclusive Economic Zone.(AU)

Os peixes-pescadores de profundidade da subordem Ceratioidei (Lophiiformes) são representados por cerca de 170 espécies válidas que apresentam algumas das adaptações anatômicas e reprodutivas mais extraordinárias entre os vertebrados, incluindo extremo dimorfismo sexual e parasitismo masculino. No presente estudo reportamos sobre a diversidade e distribuição de espécies raras de Ceratioidei coletadas durante as expedições ABRACOS (Acoustics along the BRAzilian COaSt) realizadas ao largo do nordeste do Brasil e na Cadeia de Fernando de Noronha (Atol das Rocas, Arquipélago de Fernando de Noronha e montes submarinos associados). Chaenophryne ramifera, Oneirodes anisacanthus, O. carlsbergi, Gigantactis watermani e espécimes não identificados de Caulophryne, Dolopichthys e Rhynchactis são registrados pela primeira vez na Zona Econômica Exclusiva brasileira. Ceratias uranoscopus, Melanocetus johnsonii e Chaenophryne draco tiveram suas distribuições estendidas em águas brasileiras. Caulophryne, O. anisacanthus e G. watermani também são registrados pela primeira vez no Atlântico Sul ocidental. O espécime de G. watermani reportado aqui representa o terceiro espécime conhecido da espécie, e variações anatômicas de sua esca em relação à do holótipo são descritas. Com base nos espécimes examinados e na revisão de registros na literatura, 20 espécies de Ceratioidei, além de espécies não identificadas de Caulophryne, Dolopichthys, and Rhynchactis, são confirmadas na Zona Econômica Exclusiva brasileira.(AU)

Cetacean records along a coastal-offshore gradient in the Vitória-Trindade Chain, western South Atlantic Ocean / Registros de cetáceos ao longo de um gradiente costeiro-pelágico na Cadeia Vitória-Trindade, Oceano Atlântico Sul ocidental

Oceanic waters are difficult to assess, and there are many gaps in knowledge regarding cetacean occurrence. To fill some of these gaps, this article provides important cetacean records obtained in the winter of 2010 during a dedicated expedition to collect visual and acoustic information in the Vitória-Trindade seamounts. We observed 19 groups of cetaceans along a 1300-km search trajectory, with six species being identified: the humpback whale (Megaptera novaeangliae, N = 9 groups), the fin whale (Balaenoptera physalus, N = 1), the Antarctic minke whale (Balaenoptera bonaerensis, N = 1), the rough-toothed dolphin (Steno bredanensis, N = 1), the bottlenose dolphin (Tursiops truncatus, N = 2), and the killer whale (Orcinus orca, N = 1). Most humpback whale groups (N = 7; 78%) were observed in the Vitória-Trindade seamounts, especially the mounts close to the Abrolhos Bank. Only one lone humpback whale was observed near Trindade Island after a search effort encompassing more than 520 km. From a total of 28 acoustic stations, humpback whale songs were only detected near the seamounts close to the Abrolhos Bank, where most groups of this species were visually detected (including a competitive group and groups with calves). The presence of humpback whales at the Trindade Island and surroundings is most likely occasional, with few sightings and low density. Finally, we observed a significant number of humpback whales along the seamounts close to the Abrolhos Bank, which may function as a breeding habitat for this species. We also added important records regarding the occurrence of cetaceans in these mounts and in the Western South Atlantic, including the endangered fin whale.

Águas oceânicas e afastadas da costa são ambientes de difícil acesso e muitas lacunas de conhecimento sobre a ocorrência de cetáceos ainda existem. O presente trabalho fornece importantes registros realizados durante uma expedição dedicada a procurar cetáceos visualmente e acusticamente na Cadeia Vitória-Trindade no inverno de 2010. Foram observados 19 grupos de cetáceos ao longo de 1300 km de esforço, sendo identificadas seis espécies: a baleia-jubarte (Megaptera novaeangliae, N = 9 grupos), a baleia-fin (Balaenoptera physalus, N = 1), um grupo misto de baleia-minke-Antártica (Balaenoptera bonaerensis) e golfinhos-de-dentes-rugosos (Steno bredanensis, N = 1), o golfinho-nariz-de-garrafa (Tursiops truncatus, N = 2) e a orca (Orcinus orca, N = 1). A maioria dos grupos da baleia-jubarte (n=7; 78%) foram observados nos montes marinhos da Cadeia Vitória-Trindade, especialmente os montes próximos do Banco dos Abrolhos. Somente uma baleia-jubarte solitária foi observada próxima da Ilha Trindade, apesar de mais de 520 km percorridos em esforço na região. De um total de 28 estações acústicas, cantos da baleia-jubarte foram detectados somente nos montes próximos ao Banco dos Abrolhos, onde a maioria dos grupos desta espécie foi observada visualmente (incluindo grupos competitivos e fêmeas com filhotes). A presença da baleia-jubarte nos arredores da Ilha de Trindade é provavelmente ocasional, com poucos indivíduos e baixa densidade. Finalmente, um número expressivo de grupos de baleia-jubarte foi observado sobre os montes próximos do Banco dos Abrolhos, que podem funcionar como habitats reprodutivos da espécie. Adicionaram-se ainda importantes registros de cetáceos na Cadeia Vitória-Trindade e no Oceano Atlântico Sul ocidental, incluindo a baleia-fin, uma espécie ameaçada de extinção.

Reproduction of Blackfin tuna Thunnus atlanticus (Perciformes: Scombridae) in Saint Peter and Saint Paul Archipelago, Equatorial Atlantic, Brazil / Reproducción del atún de aleta negra Thunnus atlanticus (Perciformes: Scombridae) en el Archipiélago San Pedro y San Pablo, Atlántico Ecuatorial, Brasil

The reproduction of Blackfin tuna Thunnus atlanticus has been described for coastal regions, and for a long time, this species was considered to be a strictly continental spawner. Recently, this species was observed around a seamount habitat 500 nautical miles Northeast of Brazil, located between South America and Africa. In this study we describe the reproductive biology of Blackfin tuna at Saint Peter and Saint Paul Archipelago (SPSPA). Male and female gonads were sampled from December 2008 to July 2010, and analyzed macro and microscopically. A total of 361 fish were sampled (247 males and 114 females). Males were more common than females, with a sex ratio of 2.2 ♂:1♀. The fork length (FL) of all sampled specimens ranged from 38 to 98cm, and larger length classes were more frequent in males. It was possible to distinguish six maturity phases for females: immature, developing, spawning capable, actively spawning, regressing and recovering. Five phases were identified for males: immature, developing, spawning capable, actively spawning and recovering. The gonad index (GI) mean monthly values ranged from 6.6 (SD=4.1) to 58.4 (SD=34.7) for females, and from 2.6 (SD=1.3) to 66.2 (SD=30.4) for males. For both sexes, the largest GI values were observed at the beginning of the first semester of the year. Size at first maturity was estimated at 48cm FL and 55cm FL for females and males respectively. Approximately 80% of the specimens were adults and considered to be in reproductive conditions. Histological analysis of the ovaries and testes showed that most of the specimens were sexually mature and were reproductively active during all months of the year. However, females with mature ovaries, with large amounts of hydrated oocytes and post-ovulatory follicles, were mainly found from December to March, thus these months may constitute the main spawning season in SPSPA. Batch fecundity varied between 272 025 and 1 140 584 oocytes for 56 and 68cm FL females respectively. Oocyte development and spawning patterns suggest a multiple spawning behavior. The results revealed that Blackfin tuna is using the SPSPA as a spawning ground, similar to other species commonly observed in the same area during the same reproductive season.

A pesar de la importancia de las capturas del atún de aleta negra Thunnus atlanticus en el noreste de Brasil y en las cercanías del Archipiélago San Pedro y San Pablo (ASPSP), hay una escasez de información sobre su reproducción, especialmente en las islas. La reproducción del atún de aleta negra en este archipiélago se estudió de diciembre 2008 a julio 2010. Con este fin, se recolectaron 361 gónadas de hembras y machos, los machos fueron predominantemente más frecuentes en la muestra total, con una proporción sexual de 1♀:2.2 ♂. La longitud furcal todos los ejemplares muestreados varió entre 38 y 98 cm, y los machos fueron más abundantes en las clases de mayor longitud. Los valores medios mensuales del índice gonadal (IG) variaron de 6.6 (SD=4.1) a 58.4 (SD=34.7) y de 2.6 (SD=1.3) a 66.2 (SD=30.4) para hembras y machos, respectivamente. Los mayores valores de IG para ambos sexos fueron observados el inicio del primer semestre. Los análisis histológicos mostraron que la mayoría de los ovarios y testículos correspondieron a especímenes aptos para reproducirse. Sin embargo, hembras con ovarios maduros, con gran cantidad de oócitos hidratados y folículos post ovulatorios, se encontraron principalmente de diciembre a marzo, que se considera es la época de reproducción del atún de aleta negra alrededor del ASPSP.

Deepwater fish assemblages at Isla del Coco National Park and Las Gemelas Seamount, Costa Rica / Conjuntos de peces de aguas profundas en el Parque Nacional Isla del Coco y el Monte Submarino Las Gemelas, Costa Rica

The deepwater faunas of oceanic islands and seamounts of the Eastern Tropical Pacific are poorly known. From 11-22 September 2009 we conducted an exploration of the deepwater areas of the Isla del Coco Marine Conservation Area, Costa Rica and a nearby seamount using a manned submersible. The goal of the exploration was to characterize the habitats and biota, and conduct quantitative surveys of the deepwater portions of Isla del Coco National Park and Las Gemelas Seamount, located about 50km southwest of Isla del Coco. We completed a total of 22 submersible dives, spanning more than 80hr underwater, and collected a total of 36hr of video. We surveyed habitats from 50-402m and observed more than 45 species of fishes, some of which have not yet been described and are likely new to science. The diversity of fish species in deep water at Isla del Coco National Park was lower than the diversity of fishes in shallow water, and eight species groups accounted for more than 95% of the total fish biomass. The combined density of all fish species was higher at Las Gemelas Seamount (253 fishes/100m²) than at Isla del Coco National Park (138 fishes/100m²). The combined density of fishes in habitats comprised primarily of bedrock or large boulders outcrops was more than three times as high at Las Gemelas Seamount as it was at Isla del Coco National Park. This discrepancy was caused by the extremely high concentration of Anthiinae fishes in rocky habitats at Las Gemelas Seamount. Densities of fishes in the other habitats were similar between the two sites. Similarly, when estimates of fish density were plotted by slope categories the density was much greater on steep slopes, which were usually comprised of rock habitats. Also, the density of fishes was greatest on high rugosity habitats. Results of these submersible surveys indicate that seamounts in the tropical eastern Pacific Ocean may be an important source of biodiversity and that more quantitative surveys are needed to characterize the fauna of the region.

Las faunas de aguas profundas de islas oceánicas del Pacífico Tropical Oriental se conocen poco y de los montes submarinos nada. Del 11 al 22 de septiembre de 2009 llevamos a cabo una exploración de zonas profundos del Área de Conservación Marina Isla del Coco utilizando un submarino tripulado. El objetivo del estudio fue caracterizar los hábitats y las comunidades, y cuantificar las poblaciones de peces de profundidad en la Isla del Coco y los montes submarinos Las Gemelas, situados a 50km al suroeste de la Isla del Coco. Realizamos 22 inmersiones con el submarino, con más de 80 horas de observación submarina, y filmamos 30 horas de video. Investigamos hábitats entre 50-402m de profundidad y observamos más de 45 especies de peces, algunas de las cuales son especies nuevas para la ciencia. La diversidad de peces profundos en la Isla del Coco fue menor que en aguas someras, y ocho grupos de especies representaron más del 95% de la biomasa total de peces. La densidad combinada de peces fue 253 peces/100m² en Las Gemelas y 138 peces/100m² en la Isla del Coco.

Characterization of deepwater invertebrates at Isla del Coco National Park and Las Gemelas Seamount, Costa Rica / Caracterización de invertebrados de aguas profundas en el Parque Nacional Isla del Coco y Monte Submarino Las Gemelas, Costa Rica

The deepwater faunas of oceanic islands and seamounts of the Eastern Tropical Pacific are poorly known. From 11-22 September 2009, we conducted an exploration of the deepwater areas around Isla del Coco National Park and Las Gemelas Seamount, located about 50km southwest of Isla del Coco, Costa Rica using a manned submersible to survey the seafloor habitats. The goal of the exploration was to characterize the habitats and biota, and conduct quantitative surveys of the deepwater portions of Isla del Coco National Park and Las Gemelas. We completed a total of 22 successful submersible dives, spanning more than 80hr underwater, and collected a total of 36hr of video. With respect to invertebrates, our objectives were to gather quantitative information on species composition, density, distribution and habitat associations as well as to compare the invertebrate communities between the two sites. A total of 7 172 invertebrates were counted from analysis of the video collected on this project. Larger organisms were counted and placed into 27 taxonomic groups to characterize the deepwater invertebrate fauna of Las Gemelas Seamount and Isla del Coco National Park. The Shannon-Weiner Index for biodiversity (H’) was calculated to be 0.14 ± 0.02 for Isla del Coco and 0.07 ± 0.03 for Las Gemelas surveys. Although richness was fairly equal between the two sites, evenness was greater at Isla del Coco (J = 0.04 ± 0.006) when compared to Las Gemelas (J = 0.02 ± 0.01). This lower level of evenness in the community at Las Gemelas was a result of high densities of a few dominant species groups, specifically sea urchins and black corals. We also evaluated invertebrate percent cover at both Isla del Coco and Las Gemelas Seamount with respect to habitat type, slope and rugosity. Results indicated that highly rugose habitats contained the highest frequencies of all invertebrates at both sites, with the exception of glass sponges and polychaetes at Isla del Coco, which were found in greater quantities at intermediate levels of rugosity. Information obtained from these submersible surveys indicate that seamounts in the tropical eastern Pacific Ocean may be an important source of biodiversity and that more quantitative surveys are needed to characterize the fauna of the region.

La fauna de aguas profundas de islas oceánicas y de montes submarinos del Pacífico Tropical Oriental son muy poco conocidas. Para caracterizar las faunas de aguas profundas del Parque Nacional Isla del Coco y el Monte Submarino Las Gemelas, Costa Rica, llevamos a cabo un estudio cuantitativo de los hábitats y su fauna. Se tomaron videos de transectos desde un sumergible entre 50 y 402m de profundidad del 11 al 22 de setiembre 2009. Se recolectó información cuantitativa de la composición de especies de invertebrados, densidad, distribución y hábitats asociados en ambas localidades y se comparó. Se contaron 7,172 invertebrados en los videos analizados, y se ubicaron en 27 categorías taxonómicas. El Índice de Shannon-Weiner (H’) fue de 0.14 ± 0.02 para la Isla del Coco y 0.07 ± 0.03 para Las Gemelas. La riqueza fue parecida en ambos sitios pero la equitabilidad fue mayor en la Isla del Coco (J = 0.04 ± 0.006) comparado con Las Gemelas (J = 0.02 ± 0.01). Este menor nivel de equitabilidad en Las gemelas de debió a la alta densidad de unos pocos grupos dominantes, específicamente erizos de mar y coral negro. También evaluamos el porcentaje de cobertura de los invertebrados con respecto a tipo de hábitat, pendiente y rugosidad del sustrato. Los resultados indican que hábitats con alta rugosidad contiene más invertebrados en ambos sitios, excepto la esponjas silíceas y los poliquetos en la Isla del Coco, que se encontraron en mayor cantidad en niveles intermedios de rugosidad. La información obtenida con este estudio indican que los montes submarinos en el Pacífico Tropical Oriental pueden ser una fuente importante de biodiversidad y que se necesitan más estudios cuantitativos para caracterizar la fauna de la región.

Rasgos morfológicos alrededor de la Isla del Coco y de sus montes submarinos vecinos, Pacífico de Costa Rica / Morphological features around Isla del Coco and its adjacent seamounts, Pacific Costa Rica

The UNESCO GEBCO-08 bathymetric data was used to study the marine provinces around Isla del Coco. Seamounts with depths of less than 1000m from the sea surface were analyzed. Seamounts southward, south- eastward and westward of the island, were identified at depths of 300m from the sea surface, and with heights up to 2700m from the marine bottom. The ecological interconnection of these mountains with Isla del Coco has to be effective, as it could also be within the biological corridor of Eastern Tropical Pacific. A better resolution study around Isla del Coco was done to identify details of the insular platform. A seamount to 14.8km northeast of the island was found, with measured depths of 30-40m, and so far, not reported. This feature explains the presence of fishermen around this site, which is known by them as a place with high productivity. Although more studies are needed, the limits and environmental policies should be modified so as to adequately protect these seamounts, which probably have an important ecological connection with Isla del Coco. Citation: Lizano, O.G. 2012. Rasgos morfológicos alrededor de la Isla del Coco y de sus montes submarinos vecinos, Pacífico de Costa Rica.

Se utilizaron los datos batimétricos GEBCO-08 de la UNESCO para estudiar las provincias marinas alrededor de la Isla del Coco. Se analizaron las montañas submarinas que tuvieran menos de 1000m de profundidad en esta cordillera. Montes submarinos localizados al sur, sureste y oeste de la isla, fueron identificados con profundidades de 300m desde la superficie del mar, y con alturas de hasta 2700m desde el fondo marino. La interconexión ecológica con la Isla del Coco de estos montes debe ser efectiva, como lo serán también dentro del corredor biológico del Pacifico Tropical Este. Se realizó un estudio particular de mayor resolución alrededor de la Isla del Coco para identificar los alcances de la plataforma de la isla. Se encontró un monte submarino a 14.8km al noreste de la isla, con profundidades medidas de 30-40m, que no había sido reportado. Con este rasgo submarino se explica la presencia de pescadores alrededor del este sitio, un sitio conocido en el ambiente de los pescadores, pero que aún no se había asociado a algún fenómeno oceánico en particular. Aunque más estudio es necesario, de comprobarse la conectividad biológica entre los montes submarinos y la Isla del Coco, los límites y las políticas ambientales deberán ser modificados, de manera que se proteja adecuadamente este sistema ecológico.

Mesobathic chondrichthyes of the Juan Fernández seamounts: are they different from those of the central Chilean continental slope?

We compared the geographic distribution of groups of chondrychthid fishes of two physically proximal, although geographically different, regions that include the Juan Fernández seamounts and the central Chilean continental slope, both sampled at mesopelagic and mesobenthonic depths. The ridge is in the Nazca Plate, while the slope region in on the South American Plate, and is closer to the South American continent. We found six species of Chondrichthyes for the seamounts (four orders, four families). The slope sampling produced ten species of Chondrichthyes, of which Torpedo tremens De Buen 1959, was the only species in common with the Juan Fernandez area. There are clear differences between the Chondrichthyes of the two regions. These fisheries require adequate administrative modes.

Se realizó un estudio de distribución geográfica comparativa entre conjuntos de peces condrictios de dos sectores geográficamente cercanos, pero geológicamente distintos, el sector este de la cordillera sumergida de Juan Fernández y el talud continental de Chile central, a profundidades mesopelágicas y mesobentónicas. La cordillera está sobre la placa de Nazca, el talud en la Sudamericana. Comparamos familias, géneros y especies, mediante el índice de Jaccard. Hay seis especies de condrictios en los montes submarinos (cuatro órdenes y cuatro familias). El talud tiene diez especies, y únicamente comparte con la cordillera a Torpedo tremens De Buen 1959. Estos condrictios requieren modos administrativo-pesqueros adecuados.

A new species of Nezumia (Gadiformes: Macrouridae) from Fieberling Guyot, eastern North Pacific Ocean

A new species of the macrourine genus Nezumia is described from specimens collected from the crest of Fieberling Guyot in the eastern North Pacific Ocean. The new species is distinguishable from all other Nezumia species chiefly on the basis of a high number of pelvic fin rays, a relatively high number of first dorsal fin soft rays, a steep blunt snout lacking scales ventrally, a relatively weak suborbital ridge, and a moderately long, thin barbel. Although possibly endemic to the Baja California Seamount Province, the new species appears to lack close relatives among the other Nezumia species of the eastern North Pacific Ocean. It might have arrived there either from a disjunct Tethyan distribution, thus retaining close relatives among the Atlantic Ocean species of Nezumia, or by way of stepping-stone dispersal from the Indo-west Pacific Ocean.