Estudo da biologia reprodutiva e do potencial biotecnológico e alimentar de holotúrias da costa de Peniche

Dissertação para obtenção do Grau de Mestre em Aquacultura apresentada à ESTM - Escola Superior de Turismo e Tecnologia do Mar do Instituto Politécnico de Leiria.A biologia reprodutiva de duas espécies de holotúrias foi estudada através da avaliação do Índice Gonadossomático e análises histológicas aos túbulos das gónadas. O potencial biotecnológico foi realizado pela avaliação da capacidade antioxidante, antimicrobiana e antitumoral de extratos orgânicos e a avaliação do perfil lipídico foi efetuada através da quantificação da gordura total e perfil em ácidos gordos, para as três espécies

Characterising the drivers of tropical freshwater fish dynamics and abundance in the Mekong river, under environmental change

The Mekong river’s monsoon driven annual flood pulse creates a range of diverse habitats, with high levels of connectivity and primary productivity that support and trigger fish migratory dynamics and abundance. This abundance is reflected in the fact that the Mekong is the World’s most productive inland fisheries, supporting between 2.8-3.2 million tonnes of catch annually, underpinning the food security of over 70 million people.This thesis explores the impacts of climate change and anthropogenic activity on Mekong hydrology and system function, and the impacts these have on fish and fisheries. It combines an interdisciplinary approach utilising earth observation, historical fisheries data and hydrological records, alongside the application of hydrological modelling tools and the testing of new environmental DNA metabarcoding analyses, in order to explore how changes in Mekong hydrology will affect fish populations into the future.The results highlight a range of projected negative impacts of hydropower development, irrigation expansion and climate change on the dai fisheryresources, and in turn a range of significant impacts on regional fish protein availability, which primarily result from the blockage of key migratory routes caused by dam construction as well as changes in the timing of the flood pulse in key areas in the basin such as Tonle Sap Great Lake. The findings in this study urge a need to prioritise environmental conservation action centred on a need to maintain the historical flood pulse hydrologic regime of the Mekong river. Such a pulse is shown to be important in sustaining floodplain flood dynamics and habitat connectivity that maintains the critical dai fishery, enables migratory fish dynamics, and is thus key to overall regional food security