Banca de DEFESA: MARIANA MARQUES MARTINS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARIANA MARQUES MARTINS
DATA : 08/05/2019
HORA: 09:00
LOCAL: Sala 34 do icbs
TÍTULO:

Feeding habits and trophic ecology of two syntopic species of sciaenid Micropogonias furnieri and Ctenosciaena gracilicirrhus in a tropical bay in southeastern Brazil

PALAVRAS-CHAVES:

feeding, coexistence, marine fish, ontogenetic variation

PÁGINAS: 97
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
SUBÁREA: Ecologia de Ecossistemas
RESUMO:

The analysis of fish diet is of great importance to understand not only the coexistence of
these groups of organisms, but also the processes developed in ecosystem in which they
inhabit. The objective of this study was to analyze the diet of twoc Sciaenidae species,
Ctenosciena gracilicirrhus and Micropogonias furnieri and to assess the occurrence of
ontogenetic and seasonal variations in diet, besides the possible mechanisms used to
allow the coexistence of these abundant syntopic species in the outer zone of Sepetiba
Bay. The tested hypothesis is that these species closely related in form, have
partitioning of food resources to coexist in Sepetiba Bay and that occur changes in
feeding habits along the growth. The stomach contents of 198 specimens of M. furnieri
(85-280 mm of total length) and 198 of C. gracilicirrhus (49-131 mm in total length)
obtained from quarterly daytime bottom trawls performed between the winter of 2012
and the fall of 201 in three zones (internal, central and external) of the Bay of Septiba,
RJ were examined. Different patterns in diets between species, size classes and seasons
were determined by the Non-Metric Multidimensional Scalin. Significant differences
were detected in the diet between the two species (Pseudo-F = 5.16, p = 0.001) and
between size classes (Pseudo-F = 2.23, p = 0.001), but not between seasons (F = 0.36, p
= .920), according to PERMANOVA. Micropogonias furnieri fed mainly on Polychaeta
and Caprella, while C. gracilicirrhus preferred Caprella. Micropogonias furnieri
prefered Crutacea in the smaller size classes, extending to the use of Polychaeta in
larger size classes. Ctenosciena gracilicirrhus showed preference for Caprella, which
was more clearly observed in larger size classes. No significant seasonal variations were
observed for the two species. Both species presented a narrower trophic niche with
increasing in size, thus characterizing a trend towards specialization, also confirmed
through the Amundsen diagram, with M. furnieri preferring Polychaeta, and C.
gracilicirrhus specializing in Caprella. As expected, a high intraspecific overlap of
intraspecific trophic niche was observed between size classes within each species, but
not at an interspecific level, with both species using different dietary resources. The
hypothesis that the two species closely related in form present partition of the trophic
niches as a mechanism to facilitate coexistence was accepted

MEMBROS DA BANCA:
Interno - 387200 - FRANCISCO GERSON ARAUJO
Externo à Instituição - LUCIANO NEVES DOS SANTOS
Externo à Instituição - MARCIA CRISTINA COSTA DE AZEVEDO
Externo à Instituição - RAFAEL DE ALMEIDA TUBINO