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Diaz-Diaz O.,Instituto Oceanografico Of Venezuela | Rios B.,University of the East Venezuela
Pan-American Journal of Aquatic Sciences | Year: 2014

Syllidae is the best known family of polychaetes in Venezuela with 60 species recorded belonging to 15 genera. In this note, Proceraea anopla (Monro, 1933) is reported for the first time for both Venezuela and the southern sector of the Grand Caribbean region, increasing the knowledge of the biodiversity of the family for the region. Source

Semidey D.,University of the East Venezuela | Marquez A.,University of the East Venezuela | Lodeiros C.,University of the East Venezuela | Lodeiros C.,Instituto Oceanografico Of Venezuela
Zootecnia Tropical | Year: 2010

Growth and survival of juvenile pearl mother Pinctada imbricata was evaluated through six months of culture in suspended hanging ropes and pearl nets using a longline in Turpialito Bay, Cariaco Gulf, Venezuela. Pearl oyster seeds 15 mm long were cultured, evaluating survival, shell length, muscle, rest of the body and byssus mass monthly. Variations of salinity, temperature, chlorophyll a, seston, solved oxygen and shell fouling, were determined every two weeks. After six months, the oyster reached dorso-ventral length close to 50 mm. Shell growth pattern was similar for both types of culture, although byssus mass was higher in hanging ropes, while shell length was greater in pearl nets. No significant differences were found in body mass. Survival showed similar patterns in both culture systems, although a decrease in numbers occurred in January for the oysters in pearl nets, associated to the presence of the gastropod Cymatium sp. The phytoplanktonic biomass was positively correlated to growth in P. imbricata, showing to be an important factor in growth modulation. The results suggest the use of the rope system for the culture of P. imbricada. Source

Moreno C.,Instituto Nacional Of Investigaciones Agricolas | Graziani C.,University of the East Venezuela | Nunez J.G.,Instituto Oceanografico Of Venezuela | Villaroel E.,University of the East Venezuela
Zootecnia Tropical | Year: 2011

The development of a fishery industry in any country requires biological, ecological and marketing studies about the natural source to be exploited. In this sense, decapods crustaceans in the communities of Punta Araya, Chacopata and Playa Patilla in Sucre State-Venezuela were studied for thirteen months. A total of 1826 crabs, belonging to 7 families, including 16 species and 1 subspecies, were collected. Crab biodiversity, equivalence, abundance, dominance, permanence and affinity amongst the 3 localities, as well as the gender proportion and population recruitment of the 3 main crab species present at each locality were analyzed. Crab total biodiversity was 1,22 bits/ind., equivalence oscillated between 0,16 y 0,85; abundance varied from 0,27 to 1,36. The species Callinectes ornatus was the unique species constantly found on the communities studied and also the more abundant on each locality; showing an average value of 79,63% and a gender proportion of 1:1. The average crabshells length and biomass were 65,12 mm ± 22,03 and 20,91g ± 18,87, respectively; both parameters showed higher for the male than female gender. A comparison of the growth equation obtained indicate that C. ornatus has a major alometric growth with recruitment all over the year but showing two main peaks on March and October. The physic-chemical parameters were similar for the three localities studied, except during the upwelling periods where the phytoplankton blooms providing higher food availability not only for crab larvae development but also for many other organisms. The crab C. ornatus might become an important element of basic fisheries that could contribute to improve the socio-economic status of the fishery communities settled on the east coast of Venezuela; however, it is necessary to carry out additional biological studies in order to achieve potential steady fisheries. Source

Mengual M.,University of the East Venezuela | Lodeiros C.,University of the East Venezuela | Lodeiros C.,Instituto Oceanografico Of Venezuela | Marquez A.,University of the East Venezuela
Zootecnia Tropical | Year: 2011

The winged oyster Pteria colymbus is distributed in western Atlantic, from North Carolina to south of Brazil. Juveniles of P. colymbus of 32 mm (dorso-ventral axis) were cultivated in cylinders made from plastic net, suspended at 1,5 m in a long line in the Bahía de Mochima, Sucre state. Once a month, survival and shell length was determined, as well as the mass for the shell, muscle and rest of body parts. Additionally, temperature, salinity, dissolved oxygen, seston and phytoplanktonic biomass was determined in the location. The different body parts showed differential growth patterns during the experimental period, due to different energetic demands needed for their production and the availability of energy sources in the environment. At the end of the experiment, P. colymbus increased in dorso-ventral length and total tissue mass in 68 and 390%, respectively. The growth of the tissue mass was not exponential, showing growth only in the last months, which suggests that the oysters were under stress conditions induced by the low phytoplankton availability and high temperatures. The low observed growth, along with the low final survival (30%) allows to determine that the studied area is not suitable for the culture of this species, than can be performed in other areas of eastern Venezuela such as Cariaco Gulf. Source

Gonzalez A.,Instituto Limnologico UDO | Mendoza J.,Instituto Oceanografico Of Venezuela Udo | Arocha F.,Instituto Oceanografico Of Venezuela Udo | Marquez A.,Instituto Oceanografico Of Venezuela
Zootecnia Tropical | Year: 2012

We evaluated the level of exploitation of Pseudoplatystoma fasciatum in the Caicara-Cabruta Orinoco sector using the analytical model of Thompson and Bell and the length of the fish landed by the main fishing port in the region between January 2007 and December 2008. Total mortality Z was determined by different methods: catch curve, Beverton and Holt and Sssentongo and Larkin while natural mortality M was calculated using the empirical equations by Pauly, Rikhter and Efanov, Srinath and Alverson and Carney. The values of Z and M used to estimate the rate of exploitation and application of the Thompson and Bell model were selected by using the averages and confidence intervals obtained from each method. Maximum sustainable yield (MSY) and fishing mortality F was established from the yield per recruit curve, using the benchmark F0.1. Biomass per recruit and spawning biomass per recruit was also determined using as reference points F50% and F40%, respectively. Z values were between 0.31 (0.29 to 0.34) according Beverton and Holt and 0.35 (0.34-0.37) according Ssentongo and Larkin while M ranged from 0.12 (0.11 to 0.14) according Srinath and 0.24 (0.22 to 0.26) according Pauly. According to the values of exploitation rate and F estimated in the different scenarios analyzed in the current conditions of capture of P. fasciatum in the Caicara-Cabruta Orinoco sector the species is between heavily exploited and overexploited, requiring the implementation of restrictive measures for proper management. Source

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