Banca de DEFESA: LORENA SOARES AGOSTINHO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LORENA SOARES AGOSTINHO
DATE: 22/08/2025
TIME: 13:30
LOCAL: SALA DE REUNIÕES DO DECOL/CB/UFRN e Goggle Meet (https://meet.google.com/hbk-yuwc-hqw)
TITLE:

Ecology and Phylogeography of the Scaled Sardine (Harengula sp.) in the Southwestern Atlantic with a Focus on an Island Population

KEY WORDS:

Spatial ecology; Feeding ecology; Trindade e Martim Vaz; Fernando de Noronha; Clupeidae; Citizen Science.

PAGES: 130
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

The scaled sardine (Harengula sp.), an important ecological and fishery resource in the Southwestern Atlantic, was investigated in terms of its genetic structure, spatial ecology, and feeding ecology, focusing on the oceanic archipelagos of Fernando de Noronha (FNA) and Trindade and Martim Vaz (TMV), as well as the Brazilian coast. The genetic approach encompassed all regions, while spatial and feeding ecology analyses were conducted in FNA. Sardines from 21 localities were analyzed, with 187 mitochondrial control region sequences. Four genetically structured populations were identified: TMV, FNA, Northern Coast, and Southern Coast (Geneland, φST, AMOVA analyses). TMV showed high genetic differentiation and low haplotypic and nucleotide diversity, suggesting strong isolation and a possible founder effect. FNA was genetically isolated from the mainland, showed high haplotypic diversity, and lacked internal structure between its inner and outer reef systems, suggesting population stability. Geographic barriers such as oceanic distance and depth, along with historical processes like sea-level regressions and submarine topography, likely contributed to the observed genetic patterns. In FNA, Harengula sp. has been at the center of socio-environmental conflict for decades. The results of this study provide key insights into the species’ population ecology, supporting science-based management and conservation. Regarding spatial ecology, participatory monitoring based on citizen science recorded 8,772 schooling events across 17 beaches between November 2021 and April 2024. Spatiotemporal analyses revealed higher occurrences of schools on sandy beaches located on the inner shelf, especially during the dry season, with no significant influence of swell events or lunar phases. These findings have relevant ecological and social implications, offering direct support for participatory management and decision-making, helping to reduce conflicts and strengthen conservation strategies aligned with the livelihood of traditional communities. Feeding ecology was assessed through stomach content analysis of 183 individuals from three size classes, comparing diet composition with zooplankton availability across three beaches. Diets were dominated by copepods, especially Oithona, which were highly abundant in the environment. However, selectivity indices indicated a preference for less abundant prey such as Mysidacea, suggesting selection of nutritionally richer items. Ontogenetic variation was observed, with smaller individuals consuming smaller prey and larger individuals exhibiting a more diverse diet including more mobile prey. Sancho Beach stood out as a key foraging area due to its high zooplankton abundance. This thesis presents an integrated and unprecedented approach to the ecology and phylogeography of Harengula sp. in Brazilian oceanic islands. The species plays a key ecological role and occupies a critical interface between environmental conservation, social justice, and governance in insular territories. The findings contributed directly to the 2025 revision of the Sardine Fishing Agreement within the Marine National Park of Fernando de Noronha. The integration of genetic, ecological, and social data provided a robust foundation to inform public policies for sustainable management, food security, and the recognition of traditional knowledge in Fernando de Noronha, Brazil’s only permanently inhabited oceanic island.

COMMITTEE MEMBERS:
Externo à Instituição - ANDERSON VILASBOAS DE VASCONCELLOS - UERJ
Externo à Instituição - ARTHUR DE BARROS BAUER - UFRJ
Presidente - 1378974 - LIANA DE FIGUEIREDO MENDES
Externa à Instituição - MARINA VIANNA LOEB
Externa à Instituição - NATÁLIA CARVALHO ROOS - UFF