Banca de DEFESA: VINICIUS DA SILVA ALVES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : VINICIUS DA SILVA ALVES
DATE: 08/06/2026
TIME: 14:00
LOCAL: Google Meet (https://meet.google.com/cpo-wodx-kmo)
TITLE:

Fish processing discards and the structuring of fish assemblages in surf zones: a taxonomic and functional approach in Caiçara do Norte, Brazil

 

KEY WORDS:

Artisanal fishing communities; Biotic homogenization; Artisanal fisheries; Sciades poops; Food subsidies.

 

PAGES: 106
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Human population growth and the expansion of coastal activities have increased anthropogenic impacts on marine ecosystems, particularly on beaches, which are highly dynamic and biologically diverse environments. In these environments, artisanal fisheries represent a recurrent source of organic detritus, often directly deposited on the beach, constituting a potential food subsidy for coastal fauna. However, few studies have focused on the effects of these remnants on the structure of the surf-zone ichthyofauna. The aim of this study was to assess how the disposal of fishery detritus from artisanal fishing, together with abiotic variables and seasonality, influences the abundance, biomass, assemblage composition, and taxonomic and functional diversity of the surf-zone fish assemblage. Based on optimal foraging theory predictions and the effects of predictable anthropogenic food subsidies, we hypothesized that areas with fish discard would exhibit higher abundances and biomass, and lower alpha diversity and functional richness. The study was conducted in Caiçara do Norte, on the northern coast of Rio Grande do Norte, Brazil, between October 2024 and September 2025. The ichthyofauna was sampled monthlyusing beach seine hauls across three areas with different levels of anthropogenic impact and hydrodynamics, encompassing both dry and rainy seasons. Environmental variables were measured in the field, and the data were analyzed using univariate and multivariate approaches, including PCA, PCoA, PERMANOVA, NMDS, LMM, GLMM, RDA, and piecewise SEM. A total of 3,466 individuals, distributed across 30 species, were recorded, with higher biomass during the dry season and greater abundance and biomass in the impacted area. Fish discard indirectly affected assemblage diversity, mediated by increased abundance, which in turn enhanced alpha diversity but reduced functional richness. Functional redundancy was positively influenced by alpha diversity and negatively influenced by functional richness. The assemblage composition varied spatially and temporally, being strongly influenced by salinity, water transparency, algal biomass, and the presence of solid waste. It can be concluded that the disposal of fish processing detritus, together with environmental factors and seasonality, may directly and indirectly alter the structure of the surf-zone fish assemblage, promoting biotic homogenization and highlighting the need for proper management, reuse of these detritus, and the implementation of awareness-raising and enforcement actions in artisanal fishing communities.

 

COMMITTEE MEMBERS:
Externa à Instituição - LUIZA PRESTES DE SOUZA - UVA
Externo à Instituição - BIANCA BENTES DA SILVA - UFPA
Presidente - 1545394 - FULVIO AURELIO DE MORAIS FREIRE