Biology of Grapsus grapsus (LINNAEUS, 1758) (Brachyura, Grapsidae) in the Saint Peter and Saint Paul Archipelago, Equatorial Atlantic Ocean

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efecto del color del oponente en el comportamiento agresivo del Grapsus grapsus (Linnaeus, 1758) (Crustacea, Decapoda)

[ES] El comportamiento agresivo del cangrejo moro (Grapsus grapsus) ante un modelo de competidor potencial no varió en función del color corporal de este último. No obstante, se observaron cambios en dicho comportamiento en función del tamaño del individuo residente, aumentado la intensidad de los ataques cuanto menores eran las asimetrías en talla

El uso de la información genética en la gestión de la biodiversidad marina de islas oceánicas : el cangrejo moro "Grapsus adscensionis" en la Macaronesia

Máster Oficial en Gestión Costera

Effect of different live prey, Grapsus grapsus Linnaeus 1758 and Plagusia depressa Fabricius, 1775 zoeas,over histology and biochemical composition of common octopus, octopus vulgaris Cuvier, 1797 paralarvae

[EN] Since paralarval rearing is still the main bottleneck for the development of octopus culture, the aim of the present study was to obtain some information on the feeding strategy and nutritional requirements during paralarval stage. For that purpose just hatched out octopus paralarvae were fed with live preys in three different combinations, trying to match their natural food: Enriched Artemia metanauplii, Grapsus grapsus zoeas supplemented with enriched Artemia, and Plagusia depressa zoeas supplemented with enriched Artemia. Paralarval treatments were carried out during 28 days in triplicates; fibre glass 120 l tanks in flow through system were used. Growth, in terms of dry body weight, mantle length and width, was determined each seven days. A histological study of the paralarval development was carried out. Biochemical composition of preys and paralarvae were determined. Growth was significantly better in paralarvae fed with zoeas and Artemia than in those fed only with Artemia, from day 8 after hatching. Besides a clear effect on the digestive gland histology morphology was observed.

Biología de la reproducción del cangrejo blanco Plagusia depressa (Fabricius, 1775) y cangrejo moro Grapsus grapsus (Linneus, 1758) en el litoral de Gran Canaria

[ES] La familia Grapsidae comprende el conjunto de cangrejos ecológicamente más diverso, dado que existen especies marinas, de agua salobre, dulceacuícolas, anfibias e incluso terrestres (Ruppert y Barnes, 1996). El presente trabajo se ha centrado en el estudio poblacional y reproductivo de dos especies de dicha familia: Grapsus grapsus y Plagusia depressa. Para ello se evaluaron las épocas de puesta, la proporción entre sexos y la fecundidad. Por último, se estudió el desarrollo embrionario para ambas especies. El objetivo de este trabajo fue la obtención de la información necesaria para realizar el cultivo en cautividad de las mismas. Bien para la utilización de las zoeas como presas vivas de otros cultivos, o bien para su producción, ya que estas dos especies de grápsidos poseen un gran potencial económico, dada su importancia marisquera, especialmente en el caso de Plagusia depressa, donde sus poblaciones naturales sufren graves retrocesos.

Biology of Grapsus grapsus (LINNAEUS, 1758) (Brachyura, Grapsidae) in the Saint Peter and Saint Paul Archipelago, Equatorial Atlantic Ocean

Eleven expeditions were undertaken to the Saint Peter and Saint Paul Archipelago to study the reproductive biology of Grapsus grapsus, providing additional information on limb mutilation and carapace colour. MATURE software was used to estimate morphological maturity, while gonadal analyses were conducted to estimate physiological maturity. The puberty moult took place at larger size in males (51.4 mm of carapace length) than in females (33.8 mm), while physiological maturity occurred at a similar size in males (38.4 mm) and in females (33.4 mm). Above 50 mm, the proportion of red males increased in the population, indicating that functional maturity is also related to colour pattern. Small habitat and high local population density contributed to the high rate of cannibalism. The low diversity of food items, absence of predators of large crabs and high geographic isolation are the determinants of unique behavioural and biological characteristics observed in the G. grapsus population.

Ecologia alimentar e biometria de duas espécies de raias de espinho dos Açores : uma análise ecológica e perspetiva para turismo subaquático

Dissertação de Mestrado em Gestão e Conservação da Natureza.

Utilización de cangrejo y harinas en un pienso para pulpo común Octopus vulgaris

The present work evaluates whether the addition of 2 species of crab (Portunus pelagicus and Grapsus grapsus) as attractants (10%) in experimental moist diet based in discarded bogue (Boops boops) may increase ingestion and growth in O. vulgaris. Besides, another diet based on flour, made from discarded bogue and G. grapsus, was tested. Finally, a 40-60% discarded bogue-crab P. pelagicus was provided as a control diet. Four male octopuses, kept The present work evaluates whether the addition of 2 species of crab (Portunus pelagicus and Grapsus grapsus) as attractants (10%) in experimental moist diet based in discarded bogue (Boops boops) may increase ingestion and growth in O. vulgaris. Besides, another diet based on flour, made from discarded bogue and G. grapsus, was tested. Finally, a 40-60% discarded bogue-crab P. pelagicus was provided as a control diet. Four male octopuses, kept in PVC net cages in the same tank, were fed each diet for 8 weeks and several parameters were calculated: absolute growth rate (AGR, g./day), standard feeding rate (SFR, %/day) and feed efficiency (FE). The addition of crab to the diet under the conditions described did not improve ingestion, growth or feed efficiency in this species, while the flour based diet generated negative growth.

The effects of supplementation of decapod zoea to Artemia basal diet on the digestive gland histology and the fatty acid composition in common octopus (Octopus vulgaris) paralarvae.

[EN]The present study aimed to evaluate the effect of the supplementation of different crab zoeas to enriched Artemia basal diet for O. vulgaris paralarvae during the first month of life. Paralarvae were fed using: enriched Artemia nauplii alone and Artemia co-fed with either first zoea stages of Grapsus adscensionis or Plagusia depressa. The experiment was carried out over a period of 28 days, in 0.12 m3 tanks with a flow-through rearing system. Growth in dry weightas well as mantle length and width were assessed weekly. Additionally, prey and paralarvae fatty acid composition and digestive gland (DG) histology were evaluated.