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Who are the Gadiformes and Why Should We Study Them?

Fishes of the order Gadiformes (e.g., cods, hakes, rattails and their allies) inhabit cool waters in every ocean of the world and are the targets of some of the most important commercial fisheries. They occur throughout the water column in high latitudes—from deep-sea benthic habitats (close to the bottom) to coastal waters—but are found mainly in the deeper depths of tropical seas.

Gadomus arcuatus (Family Bathygadidae) has a very long chin barbel for searching for food and long tactile rays in the pelvic and dorsal fins; characters that are often lost upon collection. This is a great example of how direct observations can provide new information on behavior and morphology, including live coloration.Gadomus arcuatus (Family Bathygadidae) has a very long chin barbel for searching for food and long tactile rays in the pelvic and dorsal fins; these characters are often lost upon collection. This is a great example of how direct observations can provide new information on behavior and morphology, including live coloration. Click image for credit and larger view.

In fact, gadiform fishes are among the most diverse group of fishes inhabiting deep waters, and in some areas they are the dominant species in terms of biomass, making them of great ecological importance. In other cases, such as the giant grenadier (Coryphaenoides pectoralis), they are at the top of the food chain and have few, if any, predators of their own.

Despite their great commercial and ecological significance, and a long history of taxonomic study, our knowledge of the evolutionary relationships (systematic) and the taxonomy of these fishes is still unclear. Currently, researchers that study the diversity of fishes in this group recognize anywhere between 11 and 14 families, about 75 genera, and more than 500 species. Only two species are known to reside in freshwater habitats.

Some of the gadiform fishes we have seen during Océano Profundo 2015 are rattails or grenadiers, which belong to the Family Macrouridae. This family is the most diverse within the gadiforms, with almost 400 recognized species. They have a worldwide distribution and are found at great depths, from the Arctic to the Antarctic. Members of this family are among the most abundant deep-sea fishes. An important commercial fishery exists for the larger species, such as the round-nose grenadier (Coryphaenoides rupestris) and the rough-head or onion-eye grenadier (Macrourus berglax). Because these are long-lived species that reach maturity at a relatively old age and have very low reproduction rates, they are highly vulnerable to over-exploitation and have a low resilience to fishing.

Early research efforts in the area have included trawling (sampling with large nets), as well as a few dives with the Alvin and the Johnson-Sea-Link submersibles (both manned deep-ocean research submersibles). However, most of these earlier dives were in waters less than 1,000 meters.

With the Okeanos Explorer‘s dual-bodied remotely operated vehicle (ROV) system, Océano Profundo 2015 has provided the opportunity to capture high-quality and high-resolution imagery of gadiforms in deep waters, as the expedition focused on unexplored areas at depths mostly beyond 1,000 meters.

ROV Deep Discoverer has two high-definition underwater video cameras and the newest lighting technology, while Seirios has a camera suspended above the other ROV and serves to illuminate and image the surroundings. The technology used in these submersibles and the skilled pilots capture amazing videos and close ups of the fishes that help us to improve our understanding of deep-sea creatures in their natural habitat. These videos are opening a window into fish behavior (e.g., swimming, searching for food sources falling from above, etc.) and are providing information on morphological characteristics (e.g., coloration, length of chin barbels, fin filaments, etc.) usually lost due to damage to the fish when being abruptly pulled to the surface from trawling or after being stored in museums for tens to hundreds of years. Additionally, information of the different benthic surfaces and depths they inhabit is important.

We saw different species in different habitats (from muddy bottoms to rock walls) and depths (3,800-450 meters). For example, the rattail Coryphaenoides armatus occurred in some of the deepest areas explored, along rock walls at depths ranging from ~3,300-3,800 meters, whereas other species were found much shallower. For instance, the grenadier Gadomus arcuatus was imaged at 900 meters in a very complex, rocky habitat.

The resolution of some of the videos allows counting fin rays of some of the fishes (that was amazing!). These characters are key among others to identify rattail species. Thirteen rattails from at least two families were observed (Macrouridae and Bathygadidae), including Nezumia bairdii, Gadomus arcuatus, Hymenocephalus sp. and several species of Coryphaenoides. We are still working on the identification and conferring with other specialists in the group. Despite of the great advantages of recording these fishes, it is possible that some of the images will not be enough to identify them at species level, and future research cruises to collect samples will be needed.

Given the commercial and ecological importance of this group of fishes, it is important to clarify the taxonomy and the systematics of the group and further understand their habitat usage in deep waters. This basic knowledge provides needed understanding for efforts to conserve the biological diversity of gadiform fishes and to inform fisheries management.

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Descubren nuevas especies de moluscos marinos en Baracoa y Maisí

Un equipo de investigación hispano-cubano descubrió 18 nuevas especies de moluscos marinos gasterópodos, de ellas 16 en la Bahía de Taco, ubicada en el sector Baracoa del Parque Nacional Alejandro de Humboldt (PNAH), sitio declarado Patrimonio Natural de la Humanidad por la Unesco, y el resto en Punta Caleta, situada en la Reserva Ecológica Maisí-Caleta.

Astyris hartmanni

Se trata de una valiosa contribución al conocimiento de la biodiversidad en las dos mil 250 hectáreas de superficie marina del PNAH, que incrementa hasta 502 el número de moluscos inventariados en un catálogo para su estudio por la ciencia cubana, y genera posibilidades para la conservación de la fauna en esas áreas protegidas.

La descripción de los diminutos caracoles endémicos, cuyos ejemplares no superan en tamaño los cuatro milímetros de ancho por ocho de largo, se hizo dentro del inventario malacológico emprendido por los destacados biólogos Jesús Ortea, profesor jubilado de la Universidad de Oviedo (España), y José Espinosa, del Instituto de Oceanología de La Habana.

Uno de los moluscos fue bautizado con el nombre de Astyris hartmanni, en honor a Alejandro Hartmann Matos, historiador de la ciudad de Baracoa, por su reconocido apoyo a los estudios de la biodiversidad en Baracoa y Maisí, desde finales de los años 60 del pasado siglo hasta el presente.

Con las pesquisas también contribuyeron los baracoenses Antonio Ruiz Blep (biólogo marino), Norvis Hernández Hernández (especialista), Balvino Méndez Medina (guardaparques), y Geovanys Rodríguez Cobas, jefe del sector Baracoa del PNAH, quien elabora su tesis para optar por el grado académico de máster en Manejo Integrado de Zonas Costeras, en la Universidad de Oriente, de Santiago de Cuba.

“Realizamos cuatro expediciones de prospecciones y muestreos durante el mes de septiembre de 2013, y luego en marzo, junio y agosto de 2014, en tres localidades: Nibujón y las Bahías de Taco y Yamanigüey”, explica Geovanys.

“Los muestreos -agrega- se efectuaron mediante buceo autónomo y con snorkel, utilizando métodos directos (censos visuales cualitativos y toma de fotografías) e indirectos (colecta de sustratos bióticos y abióticos, y la revisión de las tanatocenosis).

“Se escogieron los sitios mencionados teniendo en cuenta las condiciones del mar para el buceo autónomo hasta una profundidad máxima de 16 a 30 metros. Los resultados, aún preliminares, reflejan buenas potencialidades de la biota marina de esos sitios.

“Continuaremos los muestreos, ampliando las áreas y las profundidades de colectas, en diferentes épocas del año, teniendo en cuenta la estacionalidad de las algas y su fauna asociada. Los resultados serán incorporados al plan de manejo de esos espacios protegidos”, subrayó el directivo.

Según la Enciclopedia colaborativa en la red cubana (EcuRed), los gasterópodos (Gastropoda, del griego γαστήρ gaster, “estómago” y ποδη poda, “pie”) son los caracoles, babosas y liebres de mar más conocidos, numerosos y variados en cuanto a la forma de sus conchas: convexa, globosa, plana, turriculada, cónica y arrollada en espiral.

Se caracterizan por poseer una cabeza provista de tentáculos sensoriales, un cuerpo generalmente protegido por una concha univalva, y un pie ventral muy desarrollado que les permite la locomoción por deslizamiento.

Actualmente se conocen unas 30 mil especies que habitan los medios marinos, dulceacuícolas y terrestres, lo que los convierte en la clase más abundante de moluscos.

Especies descubiertas en Baracoa
Costoanachis geovanysi
Astyris hartmanni
Astyris joseantonioi
Intelcystiscus mariae
Granulina benitoi
Granulina eideri
Granulina oneili
Osvaldoginella alejandrae
Gibberula laritzae
Gibberula norvisae
Dentimargo tonyi
Eratoidea espinosai
Prunun tacoensis
Mitromorpha bella
Acteon baracoensis
Turbonilla calina
En Maisí
Dentimargo osmayi
Dentimargo rogeri

Fuente: http://venceremos.cu/guantanamo-noticias/1487-descubren-nuevas-especies-de-moluscos-marinos-en-baracoa-y-maisi

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