Banca de DEFESA: JOSAFÁ JOSÉ DO CARMO REIS JUNIOR

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JOSAFÁ JOSÉ DO CARMO REIS JUNIOR
DATE: 16/01/2023
TIME: 14:00
LOCAL: https://meet.google.com/enf-aeqo-vxh
TITLE:

Application of geometric morphometrics techniques to understand ecological aspects of marine fish in northeastern Brazil

KEY WORDS:

geometric morphometrics, demersal fish, trophic ecology, habitat access, fish phenotypic expression, tropical marine habitats

PAGES: 83
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUMMARY:

The organism's phenotype is the result of the interaction of a set of genetic, ecological, and environmental factors. Functional morphology investigates these phenotypic variations and geometric morphometry serves as a tool that helps in the understanding of ecological phenomena related to morphology. In this work we use geometric morphometry techniques on the marine fish body to understand ecological aspects linked to trophic ecology and habitat access at a community level. Fish were collected along the continental shelf of northeastern Brazil (4-9°S), and underwater footage was used to classify bottom habitat type into SWCR (sand with corals and rocks), Algae, and Sand. Individuals were photographed in lateral view, and shape was extracted using landmarks or contours techniques along the individuals' bodies. In total we analyzed 120 species distributed in 16 orders and 45 families of demersal fish. The relationship between body shape and trophic ecology indicated that lower trophic levels (herbivores and omnivores) are characterized by a deep body and large dorsal and anal fin bases. Top predators showed an elongated body and narrow fins. Using a multiple linear regression, we found that 46% of the variability in trophic level can be explained by morphometric variables, with increasing trophic level related to body elongation and fish size, the first time such a model has been proposed. Interestingly, intermediate trophic categories (e.g., low predators) showed morphological divergence for a given trophic level. The relationship between body shape and habitat type at first did not indicate clear patterns, when looking at the volume and morphological dispersion of the morphospace. However, when we considered the morphospace composed of the species with the highest abundances in each habitat type (All species present in the habitat, species with abundance ≥ 25% and with abundance ≥ 50%), we concluded that there is a tendency to find fish with more elongated body shape in the Sand type habitat when compared to the Algae and SWCR habitats. Overall, the 120 species are divided among 13 main fish shape groups, and body elongation rate was the main axis of variation found. The morphological characteristics found are directly related to swimming performance, where success in prey capture (e.g., top predators) and habitat access (species adapted to live in an open environment with high water flow velocity, e.g., sand habitats) are favored in species with elongated body shape. Morphological proximity had low congruence with the phylogenetic tree, indicating that our morphological approach cannot be used to observe phylogenetic proximity. Our results can be expanded to other tropical or non-tropical systems, showing that morphometric data can provide important insights into the functional characteristics of fish, especially in trophic ecology and habitat use.

COMMITTEE MEMBERS:
Presidente - PAULO JOSE DUARTE NETO
Interno - ANTONIO SAMUEL ALVES DA SILVA
Interna - TATIJANA STOSIC
Externo ao Programa - 1740405 - FRANCISCO MARCANTE SANTANA DA SILVA - UFRPEExterna à Instituição - NIDIA NOEMI FABRÉ - UFAL