Ecological study of nudibranchs in the Armona biodiversity hotspot

• Autor(a) principal: Hoett, Sandra
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/15081
• topic: Lesmas do mar; Nudibrânquios; Agregações de ouriços-do-mar em substrato móvel; Biodiversidade; Ria Formosa; Macrobentos; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

Since the 1980s, scientific interest in nudibranch species has grown due to their potential in biotechnology and neurobiology. But only a limited number of ecological studies have been undertaken specifically on this mollusk group in a lagunary environment. This MSc thesis aims at assessing the nudibranch ecology of the Armona biodiversity hotspot in the Ria Formosa lagoon and at collecting information helpful to its conservation. The scope includes investigating the abundance of each species, which environment it prefers, its behaviour, biometrics and role in the trophic web as well as their relationship with the other benthos. In situ data acquisition during scientific diving forms the basis of the study. The diving survey took place during May 2018, a time of the year for which previous studies had typically observed higher densities of nudibranchs. Data gathered from 10 dives was dissimilar but consistent. Flabellina affinis was the most abundant species identified in the Armona hotspot during the survey. Whilst previous surveys pointed out to other species of nudibranchs in the Ria Formosa area, these findings could not be confirmed in May 2018. This leads to questions about migration and general behaviour patterns of the nudibranch. Determining the density of invertebrates other than nudibranchs, observing their behavior and recording their biometrics were secondary goals of this thesis. These tasks were performed through random quadrat sampling and should contribute to the knowledge of benthos inside the surveyed biodiversity patches. The Armona biodiversity hotspot or patch consists of sea urchins accumulating in the sandy bottom of the Ria Formosa and generating livable niches for a great number of organisms. This results in the creation of a specific community with unique features