[Truncated abstract] Aspects of the biology of the commercial sea cucumber Holothuria whitmaei were investigated at Coral Bay, Ningaloo Reef, Western Australia. The study was partitioned into several components: i) spatial distribution, ii) temporal changes in behaviour and iii) reproduction biology. The spatial distribution of H. whitmaei at Coral Bay was typical of that reported in the literature. H. whitmaei had distinct preferences for outer reef habitats, including the outer reef flat and reef slope. However, the distribution of H. whitmaei within these habitats was heterogeneous, or, aggregated within certain micro-habitat zones - predominantly at the leading edge of the reef flat, perpendicular to the prevailing current. Two potential biological advantages of this distribution were hypothesised: i), that species aggregation enhances prospects for gamete fertilisation, a process which may be impeded under typical densities, and ii), large deposits of detrital matter, an important food source for holothurians, may accumulate within these zones. ... A striking feature of the reproduction biology of this species was the potential for specimens to mature asynchronously. It was hypothesised that this phenomenon may be a reflection of isolated individuals located too far from conspecifics to receive pheromone signals; cues which are known to entrain synchronous gonad development in some holothurians. Hence, it was proposed that aggregations of H. whitmaei may be important to the maintenance of population recruitment, given that animals at the periphery of species concentrations may have relatively little chance of achieving fertilisation. ... Given that H. whitmaei were observed to maintain highly specific patterns of distribution, this may have significant ramifications for trophic level cascades in the outer reef zone, particularly where this species is present in higher densities (i.e. >100 ind. ha-1). The findings of this study, apart from highlighting the spatial and temporal biological attributes which may facilitate feeding and reproductive success, also emphasised the importance of biological knowledge to the management of sea cucumber fisheries. The study highlighted the need for further research to ascertain both the importance of species aggregations to population recruitment, and of the actual densities required to achieve high rates of gamete fertilisation. Such knowledge may help ultimately to identify suitable habitats for inclusion in marine protected areas.

Thesis (M.S.)--Ohio University, August, 2009. / Title from PDF t.p. Includes bibliographical references.

viii, 49 leaves : ill. ; 29 cm Notes Typescript Includes vita and abstract Thesis (M.S.)--University of Oregon, 1988 Bibliography: leaves 44-49 Another copy on microfilm is located in Archives

Almost no work has been done on the brooding habits of Cucumaria curata Cowles 1902 from the Pacific Coast of North America. Most of the embryological investigations of holothurians on this coast have been with species having free swimming larval forms (Johnson and Johnson, 1950). Since the majority Holothurians have planktonic larvae, a study of the direct development found in C. curate might prove beneficial in comparing the ecological distribution of this species with those having planktonic larvae. The brooding type of development is found in polar species, but seldom found in warmer waters. This may have some direct effect on limiting the distribution of the species. After studying this particular type of development in C. curata, a need arose to investigate its physiology and ecology to ascertain the significance of its larval type to the distribution of the species in the community.

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 102-110). Description: xiii, 110 leaves : ill. ; 29 cm.

Holothuria scabra est l'holothurie comestible à haute valeur marchande la plus distribuée et la plus exploitée dans l'Indo-Pacifique tropical. Dès lors, et à cause de la demande croissante des pays importateurs et consommateurs, les stocks naturels de l'espèce sont confrontés actuellement un problème de surexploitation. A Madagascar, les situations économique, sociale et politique difficiles ainsi que l'insuffisance d'un plan efficace pour l'aménagement de cette exploitation, rendent la situation plus délicate encore. La surexploitation se traduit par la diminution de la production, la raréfaction de certaines espèces, la dégradation de la qualité du produit et entraîne une forte concurrence entre les exploitants et le non respect de la législation existante. Un plan d'aménagement de cette exploitation est proposé dans ce travail. Celui-ci concerne la gestion de la pêche, la restauration et la pérennisation des stocks naturels, et la valorisation des produits. L'holothuriculture est considérée comme la solution d'avenir pour pallier une demande sans cesse croissante en trépang, restaurer les stocks naturels et sauver les espèces d'holothuries menacées d'extinction. <p>\ / Doctorat en sciences, Spécialisation biologie animale / info:eu-repo/semantics/nonPublished