Acta Adriatica, Vol. 62 No. 2, 2021.
Original scientific paper
https://doi.org/10.32582/aa.62.2.1
Daily and seasonal population dynamics of Brachynotus sexdentatus (Risso, 1827) (Varunidae: Brachyura: Decapoda) in a temperate coastal lake
Salvatore Giacobbe
; Dept. of Chemical, Biological, Pharmaceutical and Environmental Sciences, Messina University, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina, Italy
Paolo De Pasquale
; Dept. of Biomedical and Dental Sciences and Morphofunctional Imaging, Messina University, Via Consolare Valeria 1, 98125 Messina, Italy
Erika M.D. Porporato
; IMC - International Marine Centre, Loc. Sa Mardini, 09170, Oristano, Italy
Abstract
The grapsoid Brachynotus sexdentatus (Risso, 1827) is a small sized Mediterranean crab, whose ecology is poorly known despite frequently cited in the scientific literature. High densities occasionally recorded in estuarine habitats suggest this opportunistic species might play a functional role in connecting benthic primary production with consumption at higher trophic levels. The brackish Lake Ganzirri (north-eastern Sicily) hosts a population of this varunid crab, whose differential distribution of juveniles and adults, respectively found on hard and soft substrates, involves different habitat preferences and consequent resource partitioning. Investigation on daily and seasonal dynamics of the soft-bottom dwelling adults showed a male biased population, with size-related differences between sex, station, season and female reproductive phase. Our data, suggesting an annual life span, prolonged spawning and related continuous recruitment, are in agreement with the intrinsic unpredictability of the colonized brackish environment. At last, preliminary in aquaria observations on the characteristic male cheliped vesicles, showed they might involved in agonistic and courtship behaviour.
Keywords
Littoral Brachyura; sex ratio; brackish lagoons; protected environments dynamics; Mediterranean
Hrčak ID:
271911
URI
Publication date:
22.12.2021.
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