BULLETIN OF THE OCEANOGRAPHIC INSTITUTE OF VENEZUELA

APROXIMACIÓN A LÍNEA BASE DEL FITOPLANCTON DE AGUA DE LASTRE, DE BUQUES QUE ARRIBARON A LA BAHÍA DE BARCELONA, ZONA NORORIENTAL DE VENEZUELA (ENERO-MAYO 2023)

Elena Hernámdez-Andrade — 2025-07-18

Phytoplankton carried by ballast water is a threat in coastal areas receiving commercial ships. In Barcelona Bay, there is traffic of ships transporting hydrocarbons, and it is important to monitor the phytoplankton in ballast water. In this sense, the oil port José Antonio Anzoátegui represents an increase in the risk of introducing invasive species through ballast water, with the potentially dangerous risk for the biological balance of the different local ecosystems. In the present study, ballast water from 33 tankers that arrived at the port between January and May 2023 was monitored. Measurements of temperature and salinity parameters were taken in both the water in the tanks and the surface water of the bay. Samples were collected with bottles (125 ml) for microscopic examination using the Utermohl method. Sixty-one species of phytoplanktonic organisms were identified, distributed in 8 cyanobacteria, 5 chlorophyta, 39 diatoms, 6 dinoflagellates, 2 coccolithophorids and 1 silicoflagellate. Diatoms were the most representative group (54%), followed by cyanobacteria (38%). The predominant genera were Trichodesmium, Navicula, Nitzschia, Synedra and Gymnodinium. The samples did not show excessive phytoplankton abundance and no potentially toxic species were detected. This research constitutes the beginning of a baseline for a possible temporal monitoring of species that are regularly transported on tankers in that port.

NUEVA ÁREA DE DISTRIBUCIÓN DEL MOLUSCO EXÓTICO Naria turdus Lamarck, 1810, (GASTROPODA: CYPRAEIDAE) PARA EL CARIBE NORORIENTAL DE VENEZUELA

Jesus Antonio Bello-Pulido — 2025-07-15

The Gulf of Cariaco is an enclave located in the state of Sucre, in eastern Venezuela, with great ecological importance because it houses a high diversity of ecosystems, several of which are used by many species as breeding grounds. Different studies have been done to determine the composition of the biota in the spaces of this body of water, but few have been directed at the presence of exotic species, something that threatens its biodiversity. In this regard, a brief review is presented of the records of non-native species in the gulf, of those that could be occupying these waters and the first record for this area of the mollusk Narias turdus, a taxon originating from the Red Sea, the Gulf of Oman and East Africa in the Indian Ocean. The discovery was made in the town of Camacuey, near the city of Cumaná. The species is distinguished by its oval-shaped shell, strong, smooth, shiny, with irregular light brown, dark brown and ochre spots, scattered dorsally and laterally, on a whitish-greyish surface; with a thick, white base, with irregular light brown, dark brown and ochre spots. The occurrence of specimens of various sizes suggests that it has not been a recent settlement and the possibility that it is in other areas of the gulf.

PALABRAS DE NOSTALGIA DEDICADAS AL PROFESOR IDELFONSO LIÑERO ARANA “MIKEL”

Juan Antonio Gomez — 2025-05-09

A mi querido hermano “Mikel“ le conocí cuando lo asignaron como mi tutor en la Maestría en Ciencias Marinas del Instituto Oceanográfico de Venezuela, sus primeras palabras al ingresar a su oficina fueron impactantes y severas, “¿Quién es usted?, soy profesor de la Universidad de Panamá y vengo a estudiar mi maestría, su respuesta fue: “Usted aquí no es un profesor, es un estudiante más y su tiempo debe dedicarlo a sus clases y a estudiar en la biblioteca por lo menos diez horas”, luego me mostró el sitio que debía ocupar y los libros que debería consultar. Casi me regreso, pero me dije “¡No!, él tiene un genio muy fuerte y yo el mío, pero aprenderé de él”, y así lo hice. Puedo decir que fue un gran maestro, no sólo para mí, sino para los que se formaron con él, ya que era un excelente profesional, la trayectoria de investigación en su área de especialidad era asombrosa. Entre las frases que siempre decía, recuerdo estas: “es blanco o es negro” o “cuando vas a hacer una cosa, hazla bien, si no, no la hagas”. Ese era él.

CARACTERIZACIÓN DE LA MACROFAUNA BENTÓNICA DE PROFUNDIDAD DEL EXTREMO NORTE DEL CARIBE COLOMBIANO

Catalina Arteaga-Flórez — 2025-05-09

The benthic macrofauna includes those organisms that live within the marine sediment and are larger than 500 μm. Their study has been relevant to determine the health of benthos due to be considered good indicators of anthropic impacts and natural disturbances. The purpose of this study was to characterize the benthic macrofauna in the block COL 10 located in the northernmost Colombian Caribbean, in order to create a base line for its management and conservation. A total of 10 benthic samples were collected with a Box Corer between 2,880 and 4,220 m depth, which were processed at laboratory, and deposited in the collections of the Marine Natural History Museum of Colombia (MHNMC) - Makuriwa of INVEMAR. A total of 321 organisms were quantified, and are included in 77 families and/or taxa and nine phyla: Annelida, Arthropoda, Bryozoa, Cnidaria, Mollusca, Nematoda, Nemertea, Platyhelminthes and Sipuncula. Annelida was the most representative group in terms of abundance and number of taxa, with Cirratulidae and Paraonidae as dominating families. The classification and ordering analyzes shown a differentiation in the community structure in stations E612 (ocean basin area) and E600 (in oceanic mountain range area). The present study provides the first contributions to the ecology and taxonomy of deep sea benthic macrofauna in the block COL 10 located in the northernmost Colombian Caribbean.

BIONOMÍA BENTÓNICA COSTERA DE LA ISLA DE CUBAGUA (VENEZUELA). I. COSTA ESTE Y OESTE

Alfredo Gómez — 2025-05-09

Between 2001 and 2004, the benthic bionomy of Cubagua Island (Venezuela) was studied. From the midlittoral, 48 transects of 100 m in length were made, marked every 25 m where a quadrata (50 cm, 0.25 m2) was placed to extract substrate and biological samples. By free-diving (apnea) we extracted representative samples by placing the material into a bag and then the macrobenthos was separate. By direct observation, distribution of communities was determined along the transect and up to 25 m on each side. At 100 m from the coast, the water temperature was measured and samples to analyze salinity and oxygen. Fishes were collected using a 25 m beach seine (mesh 5 mm). The sedimentology was studied by extracting sand from the midlittoral, 50 and 100 m from the beach. On the east coast, the sandy beaches are: Playa El Medio, El Mercado and Chiripicú; the rocky beaches with sandy portions are: Punta Charagato, Melico, La Cabecera, Chucuruco, Punta Yirú and La Garza; El Obispo is a sandy-muddy beach. On the east coast, the deterioration of the seabed is noticeable due to the transit of fast ferries whose waves resuspend sand and cover benthic life (corals) and clogging the slabs. However, the massive mortality of Acropora corals of Charagato and El Mercado cannot be attributed to the ferries, because some flourishing colonies were observed. In the west coast the sandy beaches are: Punta Arenas, Punta El Cardón, Punta El Amparo, Playa Cautaro west and Ladera Brasil; the rocky beaches are: Playa Las Iguanas, Punta La Horca, La Pedregosa, La Choleadora and Punta Brasil. In Punta Arenas, the coastal edge has been modified by a sandy point (>300 m) that enter the sea. In La Cabecera, the introduced rhodophyte algae Kappaphycus alvarezii covers part of the Millepora colonies, causing coral bleaching, this exotic species can affect the biodiversity of immense Millepora communities which are spectacular, have great ecological interest and extraordinary visual appeal. New species were collected, the crab Calyptraeotheres hernandezi Hernández-Ávila & Campos 2006 and the fish Ophioscion gomezi Cervigón 2011.

POLIQUETOS BÉNTICOS ASOCIADOS A MACROALGAS Y FONDOS BLANDOS EN ENSENADA MACURO, GOLFO DE PARIA, ESTADO SUCRE, VENEZUELA

Jorge Barrios-Montilla — 2025-05-09

The Paria gulf (Sucre state, Venezuela) has a heterogeneous coastal topography with varied environments. This is the first study of the macroalgae and polychaetes of Macuro, a population located in this gulf, with collected samples at 10 stations in May 2014. Macroalgae and polychaetes were collected in delimited areas with a quadrat and a benthic core, respectively, and preserved with formalin. Twenty-three macroalgae species were found: five Chlorophyta, four Ochrophyta and 14 Rhodophyta. The rhodophyceae Ceratodictyon variabile is a new record for the Paria gulf. The dominant species was Padina gymnospora and the most constant was Centroceras clavulatum, with low diversity values (average 1,37 bits/ind.). Seventeen species and 13 families of polychaetes were identified, with Nereididae and Spionidae being the best represented, with diversity values ranging from 0 to 2,23 bits/ind. Are recorded for the first time for the country Eunice lanai, Perinereis floridana, Ancistrosyllis jonesi and Pseudopolydora floridensis. Polychaetes are more abundant in rocky areas with macroalgae, which stimulate their development by providing them with food and shelter areas from predation. Despite being a short study, it is notable that four polychaetes are new records for Venezuela, which highlights the importance of taxonomic studies for this region.

POLYCHAETES BIODIVERSITY ASSOCIATED TO CORAL REEF-TYPE SEDIMENTS: A LONG-TERM STUDY

2025-06-01

We established a long-term monitoring program in pristine coral reef environments, targeting soft-bottom polychaetes as indicators of natural changes in their biodiversity patterns. This study allowed us to gather base-line information of richness, abundance and spatial-temporal variations of macrofaunal polychaetes, and associate these with sediment reef variables. Two sampling campaigns/year were conducted at seven stations, from 2009-2013. Sediment samples were collected near colonies of Orbicella faveolata. In the laboratory, macrofaunal samples were sieved, sorted, and preserved in Ethanol (70%). Sediment parameters were studied following standard laboratory protocols. All reef sediments had high content of sand and CaCO3 (80-85%), which is typical for reef-type sediments. This long-term study showed that the benthic macrofauna and polychaetes associated with sediments exhibit high biodiversity, and richness but low-density values, which vary in space and time, but no seasonality. A total of 5,349 individuals belonging to 27 taxonomic groups were collected. From those, Polychaetes (representing 18%) where analyzed in further detail. 980 specimens, from 69 species (31 families) were analyzed, from which 17 are new records for Venezuela. Two families presented the highest richness and abundance: Spionidae and Syllidae (6spp, 28%, and 7 spp., 9% respectively). In terms of abundance, the spionids Prionospio sp. and Prionospio cristata were the dominant species. A significant decrease in richness and abundance of polychaetes was recorded in April-2012. Likewise, organic carbon values decreased after April-2012. These variations suggest an important change in these environments that was reflected in the polychaete community in all locations.

ESTRUCTURA DE LA COMUNIDAD DE POLIQUETOS (ANNELIDA: POLYCHAETA) ASOCIADA A Thalassia testudinum BANK EX KÖNIG 1805 EN LA BAHÍA DE MOCHIMA, VENEZUELA

Ildefonso Liñero-Arana — 2025-08-31

The seagrass meadows of Thalassia testudinum grasslands constitute one of the coastal environments with a great diversity of organisms and a high productivity. In order to study the polychaete community associated with Thalassia, monthly samplings were conducted in Mochima Bay from January to December 2002. Eight replicates were taken monthly at each site, using a 14.8 cm diameter PVC corer. Each core sample was sieved through a 1 mm mesh, and the polychaetes were preserved in 8% formalin solution. The polychaetes were fixed in an 8% formalin solution. A total of 2097 specimens were collected, identifying 94 species belonging to 31 families; the families Terebellidae, Serpulidae, Spionidae and Syllidae have the greatest number of species and together represent 40.42% of the total identified species. Mangle Quemao had the highest abundance and species richness, while Varadero had the lowest. The average diversity value was 2.14 ± 0.29. A PERMANOVA analysis revealed statistically significant differences in abundance across all considered sources of variation.