Composition, structural characteristics and temporal patterns of fish assemblages in non-tidal Mediterranean lagoons: A case study

• Published in: Estuarine, coastal and shelf science coastal and shelf science, 2009-08, Vol.83 (4), p.602-612
• Main Authors: Maci, S., Basset, A.
• Format: Article
• Language: English
• Subjects: Acquatina; Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Atherina boyeri; Biological and medical sciences; Brackish; Brackish water ecosystems; coastal lagoon; community structure; ecosystem type; fish fauna; Fundamental and applied biological sciences. Psychology; Italy; Marine; Mediterranean Sea; Synecology; temporal patterns; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/j.ecss.2009.05.007

The importance of transitional water ecosystems as nursery habitats and feeding grounds for fish species is well-known. Detailed studies of colonization patterns of fish guilds in response to biotic and abiotic drivers are however unevenly distributed among ecosystem types. We address here the temporal variability of fish assemblages in small non-tidal lagoons in the Mediterranean basin. The study was carried out at the Acquatina lagoon (Lecce, Italy) where four stations, situated in two habitat types along a confinement gradient, were sampled twice per month for one year with fyke nets. Forty-five taxa ranging across 20 families were collected, with the most abundant species, Atherina boyeri, accounting for more than 95% of total abundance. Pooling all species together (excluding sand smelt), the structural features of the assemblage, relative abundance of families, and abundance of individual species all showed significant temporal patterns. Mean abundance peaked in Summer and Autumn and fell in Winter, whereas taxonomic richness and diversity were highest in Summer and lowest in Spring. Within the fish assemblage, multivariate ordination showed temporal segregation of species belonging to the same family or genus and expected to be functionally similar, suggesting that they avoid competition for space and resources by timing inward migration and peak occurrence differently. Of the environmental driving forces, which also showed temporal patterns of variation, salinity was the main factor affecting the distribution of individuals and species. The catch of young individuals of several marine species confirmed the role of this small lagoon as a nursery and feeding area, and emphasized the need for further studies.