Search

This paper provides length-weight relationships (LWR) for three species: long snouted lancetfish Alepisaurus ferox, kitefin shark Dalatias licha and little sleeper shark Somniosus rostratus. Samples were collected occasionally from 2009 to 2013. A total of 49 D. licha and 24 S. rostratus samples from the western Mediterranean Sea, and 211 samples of A. ferox from the eastern North Atlantic Ocean were recorded for LWR. For each species, regression coefficients and parameters “a” and “b” were calculated with 95% confidence interval. The LWR parameter b for all species ranged from 2.889 to 3.5048, with R2 ranging from 0.717 to 0.823., SI

Versión del editor

Small pelagic resources and particularly sardine (Sardina pilchardus) and anchovy (Engraulis encrasicholus) represent an important fishery activity for the countries bordering the Alboran Sea. This paper aims at contributing to the identification of priority species of small pelagic shared stocks in GSA01 and GSA03 (northern and southern Alboran Sea GFCM regions) for carrying out joint stock assessments and promoting new management measures that would allow the sustainability of the resources and its exploitation. The WG on small pelagic shared stocks met twice during 2011 progressing in analysing the available data on the stocks and its exploitation and building a common data base. Moreover a comparative analysis on sardine landings data from 2003-2010 in GSA01 and GSA03 was carried out explaining that the exploitation pattern in sub-areas (GSAs 01 and 03) is different but the total length-frequency distribution of sardine exploited by each country appears to be similar. A tentative in applying a LCA analysis of the Moroccan and Spanish data on sardine using different biological parameters and with the VIT software was unsuccessful but orientated for future works of the WG

Alpha-amylase activity was measured and described in five species of Mediterranean sparids: Pagrus pagrus (Linnaeus, 1758), Pagellus erytrhinus (Linnaeus, 1758), Pagellus bogaraveo (Brünnich, 1768), Boops boops (Linnaeus, 1758), and Diplodus annularis (Linnaeus, 1758). Major differences were found regarding the optimum pH and thermal sensitivity of this activity. B. boops showed low resistance at high temperatures, compared with D. annularis, which showed a higher thermal tolerance. Electrophoretic separation under native conditions (PAGE) and isoelectrofocus (IEF) revealed the existence of several α-amylase isoforms, ranging from 1-3 active fractions in the species studied. These differences are probably related to differences in their feeding habits, and having a variety of amylases can be considered an ecological advantage for those animals with this characteristic., La actividad α-amilasa intestinal fue medida y caracterizada en cinco especies de espáridos que habitan en el mar Mediterráneo: Pagrus pagrus (Linnaeus, 1758), Pagellus erytrhinus (Linnaeus, 1758), Pagellus bogaraveo (Brünnich, 1768), Boops boops (Linnaeus, 1758) y Diplodus annularis (Linnaeus, 1758). Las principales diferencias fueron observadas en el pH óptimo y en la sensibilidad a la temperatura. La actividad amilasa en B. boops demostró ser poco resistente a altas temperaturas, a diferencia de la de D. annularis, que resultó ser muy resistente. La separación electroforética en condiciones nativas (PAGE) e isoelectroenfoque (IEF) revelaron la existencia de un número de isoformas de la α-amilasa que osciló entre una y tres fracciones activas en las especies estudiadas. Estas diferencias posiblemente estén relacionadas con los distintos hábitos alimentarios de las especies estudiadas. Esta variedad de amilasas mostrada representa una ventaja ecológica para los animales que la poseen., Instituto Español de Oceanografía

The digestive proteases of bluefin tuna Thunnus thynnus (Linnaeus, 1758) were studied. Protease activity in stomach extracts showed two optima, at pH 2.0 and 3.5. Optimum activity for intestinal proteases was found at pH 10.0 and 12.0. Protease activity in stomach extracts was found to be stable at several pH, except for pH 12.0. Alkaline protease activity of intestine extracts was highly sensitive to acidic pH. Optimal temperatures found were 50 ºC for acid proteases and 60 ºC for alkaline proteases. The use of specific protease inhibitors indicated that the main presence of acid proteases was in stomach extracts, and serine proteases in intestine extracts. Active fractions in extracts were identified with SDS-PAGE., Se estudió la actividad proteasa digestiva de Thunnus thynnus (Linnaeus, 1758). Se encontraron dos óptimos de pH, tanto para la actividad proteasa ácida de los extractos estomacales (2,0 y 3,5) como para la actividad proteasa alcalina de los intestinales (10,0 y 12,0). La primera se mantuvo muy estable en un rango amplio de pH, a excepción de pH muy alcalinos (12,0). Por su parte, la actividad proteasa alcalina se vio afectada por pH muy ácidos. Los óptimos de temperatura se determinaron en 50 y 60 ºC para la actividad proteasa ácida y alcalina, respectivamente. Mediante el uso de inhibidores de proteasa se comprobó la presencia de proteasas aspárticas en los extractos estomacales y de serin-proteasas en los intestinales. La realización de zimogramas permitió identificar las distintas fracciones con actividad proteolítica presentes en cada extracto., Instituto Español de Oceanografía