Field comparison of sardine post-flexion larval growth and biochemical composition from three sites in the W Mediterranean (Ebro river coast, bays of Almería and Málaga)

Abstract

SUMMARY: Late larval stages of sardine (16-23 mm) were sampled during the 2003 spawning season in their nursery grounds located off the Ebro river mouth, on the Catalan coast, and in two bays of the Alborán Sea coasts, the Bay of Almería and the Bay of Málaga. The daily growth analysis of each sampled population revealed faster growth in the Ebro sardine larvae than in both of the Alboran Sea larval populations. This fact is supported by their greater content with age of DNA, RNA and protein. However, the significantly higher carbohydrate content of the Bay of Almería sardine larvae and a higher Fulton's index, indicative of energy storage of individuals, in both of the sardine populations sampled in the Bays of Almería and Málaga show evident differences in the daily growth of the Alborán Sea larvae from those originating in the Ebro region. Late larval growth in the Alborán Sea sardine tends to favour an increase in body mass rather than in body length. This study hypothesises that the productivity pulses off the Alboran Sea coasts induced by the north and northwestern wind regimes may be responsible for the growth pulses observed in the otolith microstructure.Keywords: sardine larvae, Mediterranean, growth, DNA, RNA, proteins, carbohydrates. RESUMEN: CRECIMIENTO Y CONTENIDO BIOQUÍMICO COMPARATIVO DE LARVAS EN POSTFLEXIÓN DE SARDINA DE TRES ZONASDEL MEDITERRÁNEO OCCIDENTAL (EBRO, BAHÍAS DE ALMARÍA Y MÁLAGA). -Estados avanzados de larvas de sardina (de 16 a 23 mm) fueron muestreados durante el invierno de 2003 en zonas de alevinaje situadas en la desembocadura del río Ebro, en la costa catalana, y en las bahías de Almería y de Málaga, en las costas del Mar de Alborán. El análisis del crecimiento diario de cada población larvaria muestreada, evidencia un mayor crecimiento en las larvas procedentes del Ebro respecto a las nacidas en el Mar de Alborán. Esta observación se corrobora con un mayor incremento con la edad de los contenidos en DNA, RNA y proteínas de la población larvaria de sardina del río Ebro. Sin embargo, un contenido significativamente mayor de carbohidratos en la población de Almería, así como un mayor índice de Fulton, indicador de energía almacenada en un individuo, en ambas poblaciones del Mar de Alborán, evidencia una estrategia diferenciada de crecimiento de estas poblaciones larvarias con respecto a las procedentes del río Ebro. En consecuencia, las larvas de sardina del Mar de Alborán muestran una tendencia a crecer más en masa que en longitud, como lo evidencia el crecimiento relativo del peso seco, DNA, RNA y proteínas en relación con su longitud estándar. En este estudio se plantea la hipótesis de que los pulsos productivos en el Mar de Alborán, inducidos por el régimen de vientos de norte y poniente, pueden ser responsables de los pulsos de crecimiento larvario, como se evidencia en las microestructuras de los otolitos.

Habitat suitability modelling for sardine Sardina pilchardus in a highly diverse ecosystem: the Mediterranean Sea

“…In the Spanish Mediterranean waters, the indicated PSH areas are dominated by the narrow shelf of the North Alboran Sea, the Ebro River area, the Catalan Sea and the Balearic plateau, which matches the known sardine spawning grounds in the region (Pérez de Rubín 1996, Olivar et al 2003, García et al 2006, Vargas-Yáñez & Sabatés 2007. These areas generally match those indicated by the adult model in December, verifying that the patchiness of the eggs closely reflects the patchiness of the spawning adults.…”

“…1 & 7), a pattern that matches the former sardine spawning grounds in the Spanish Mediterranean waters (Pérez de Rubín 1996, Olivar et al 2003, Vargas-Yáñez & Sabatés, 2007. Suitable spawning areas visually correspond to sardine adult potential distributions, which agrees with the coincidence between early winter and the beginning of the spawning season for sardine in the Mediterranean (García et al 2006 and references therein, Soma ra kis et al 2006). PSH areas were also indicated in other parts of the Mediterranean as well as in the coastal waters of Africa (Fig.…”

Biochemical composition and condition in anchovy larvae Engraulis encrasicolus during growth

“…Supporting this theory, García et al (2006) found that RNA/DNA ratios did not increase with SL in late larval stages of Sardina pilchardus. According to this, an upper limit in larval condition or RNA/DNA ratio is reached at a certain size -at the asymptotic valueafter which, despite further increase in size, larval condition or RNA/DNA ratio remain fairly constant (Pepin et al 1999, García et al 2006.…”

Multi-species larval fish growth model based on temperature and fluorometrically derived RNA/DNA ratios: results from a meta-analysis

“…Canino et al 1991, Canino 1997, Rooker et al 1997, Kimura et al 2000, Chícharo et al 2003, Catalan et al 2006, Garcia et al 2006, Lee et al 2006, Malzahn et al 2007). When fish size and water temperature between sites are similar, interpretation of results is straightforward: the group with the higher RD is in better condition since it contains more machinery (potential) for protein synthesis.…”