Papers by José Manuel Parada Encisa
Academia Biology, Oct 25, 2023
The population dynamics of the golden carpet shell clam Polititapes aureus (Gmelin, 1791) were st... more The population dynamics of the golden carpet shell clam Polititapes aureus (Gmelin, 1791) were studied over the course of six years in the ria of Arousa (Galicia, NW Spain). Density reached a value of 62.29 individuals m−2 and biomass was 76.30 g m−2. Recruitment was related to water temperature, to food availability measured as fluorescence and to density-dependent phenomena starting at 39 individuals m−2. The condition factor and mortality showed a clear annual periodicity, while growth rate G30 was biannual. Growth was fitted to a seasonal von Bertalanffy function, with L∞ = 43.6 mm; K = 0.360 y−1; C = 0.65 and ts = 1.21, with a confidence interval determined by bootstrapping. The instantaneous mortality rate for individuals aged 1 and 2 years was 0.94 in spring-summer and 0.14 in autumn-winter. The fishing mortality rate had little effect on the population. A model was built to explain the natural mortality rate as function of temperature, salinity, fluorescence, and the condition factor. The results allow the application of fishery management tools based on their population dynamics and to measure their effectiveness considering the environmental variability. They also show the vulnerability of these stocks to changes resulting from climate change.
Academia Biology, Oct 26, 2023
The population dynamics of the golden carpet shell clam Polititapes aureus (Gmelin, 1791) were st... more The population dynamics of the golden carpet shell clam Polititapes aureus (Gmelin, 1791) were studied over the course of six years in the ria of Arousa (Galicia, NW Spain). Density reached a value of 62.29 individuals m−2 and biomass was 76.30 g m−2. Recruitment was related to water temperature, to food availability measured as fluorescence and to density-dependent phenomena starting at 39 individuals m−2. The condition factor and mortality showed a clear annual periodicity, while growth rate G30 was biannual. Growth was fitted to a seasonal von Bertalanffy function, with L∞ = 43.6 mm; K = 0.360 y−1; C = 0.65 and ts = 1.21, with a confidence interval determined by bootstrapping. The instantaneous mortality rate for individuals aged 1 and 2 years was 0.94 in spring-summer and 0.14 in autumn-winter. The fishing mortality rate had little effect on the population. A model was built to explain the natural mortality rate as function of temperature, salinity, fluorescence, and the condition factor. The results allow the application of fishery management tools based on their population dynamics and to measure their effectiveness considering the environmental variability. They also show the vulnerability of these stocks to changes resulting from climate change.
Revista de biología marina y oceanografía, 2008
Natural mortality of the cockle Cerastoderma edule (L.) from the Ria of Arousa (NW Spain) interti... more Natural mortality of the cockle Cerastoderma edule (L.) from the Ria of Arousa (NW Spain) intertidal zone Mortalidad natural del berberecho Cerastoderma edule (L.
Estuaries and Coasts, 2011
... how fast the change occurs. In fact, one of the main problems with the laboratory studies is ... more ... how fast the change occurs. In fact, one of the main problems with the laboratory studies is the adaptation period prior to the experiment (Ansell and Sivadas 1973; 1981; Anger et al. 2008). Moreover, in the natural environment ...
Many different methods have been used to differentiate Cerastoderma edule (L., 1758) from C. glau... more Many different methods have been used to differentiate Cerastoderma edule (L., 1758) from C. glaucum (Bruguiere,1789). However, very few of them are fast and valid for specimens less than 10 – 12 mm length. Although the lateral visibility of the ligament has been described as a discriminating trait, it is seldom used despite the fact that it can be applied immediately. To determine the validity of this characteristic at the juvenile stage, a group of specimens from both species was identified using both this and other methods based on the relationships between different valve sizes. In all of the specimens identified with these methods as C. glaucum , the ligament could not be detected in lateral view and vice versa, whereas the contrary is true for C. edule .
La presente memoria esta incluida en el proyecto "Cartografia biosedimentaria del litoral de... more La presente memoria esta incluida en el proyecto "Cartografia biosedimentaria del litoral de Galicia:Sector Mino -ria de Pontevedra "del Plan Nacional del I+D AMB93-030,financiado por la CICYT entre 1990 y 1993 y llevado a cabo por el Area de Estratigrafia de la Universidad de Vigo y el Equipo de estudios del Bentos Marino de la Universidad de Santiago de Compostela . En ella aborda el estudio de la macrofauna bentonica de los fondos blandos submareales de la rias de Pontevedra y Aldan y la esdenada de A Lanzada , y su rela cion con la variacion espacial de las caracteristicas de los sedimentos.Tras el analisis somero de las caracteristicas del agua de fondo,como informacion meramente adicional, se procede al estudio de la distribucion espacial de las caracteristicas fisicoquimicas de los sedimientos.Esta responde a unos gradientes dominados por la configuaracion geografica y el hidrodinamismo.En la ria de Pontevedra se define un gradiente principal de tranporte de sedimie...
Revista De Biologia Marina Y Oceanografia, Dec 15, 2008
Natural mortality of the cockle Cerastoderma edule (L.) from the Ria of Arousa (NW Spain) interti... more Natural mortality of the cockle Cerastoderma edule (L.) from the Ria of Arousa (NW Spain) intertidal zone Mortalidad natural del berberecho Cerastoderma edule (L.
Estuaries and Coasts, 2012
Attached you can find the article "MULTISPECIES MORTALITY PATTERNS OF COMMERCIAL BIVALVES IN RELA... more Attached you can find the article "MULTISPECIES MORTALITY PATTERNS OF COMMERCIAL BIVALVES IN RELATION TO ESTUARINE SALINITY FLUCTUATION" to be consider for its publication in Stuaries and Coast.
Owing to the peculiar morphology of the goose barnacle Pollicipes pollicipes (Gmelin, 1789), many... more Owing to the peculiar morphology of the goose barnacle Pollicipes pollicipes (Gmelin, 1789), many different biometric variables have been used in its study. The lack of a standard morphological variable makes it difficult to compare results from different authors. This aspect takes on even greater importance, since the goose barnacle is a commercially exploited species and must be regulated with clear-cut technical measures related to its biology. The need to measure a large quantity of specimens in the management and control of the fishery calls for a biometric variable that can be processed easily and requires little training. The base of the rostrum and the apex of the subcarina form two conspicuous clefts in the capitulum of the goose barnacle, allowing a calliper to be fitted quickly and easily. The results of this study showed that the diameter of the base of the capitulum (DBC), defined as the distance between these two clefts, may be considered a consistent variable both when the same specimen is measured by two different technicians and when the measurements taken from a fresh specimen are compared with the measurements taken after the specimen has been frozen and then thawed. In order to make comparisons easier, two linear equations have been found to relate DBC and two of the more usual biometric variables: rostral-carinal distance (RC) and capitulum height (CH). The mean length at sexual maturity was also calculated in terms of DBC (13.35 mm) for specimens collected on the Galician coast (NW Spain).
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Papers by José Manuel Parada Encisa