Trophodynamics of fish assemblages associated with a Caulerpa prolifera (Forsskål) meadow in a shallow semi-enclosed embayment: preliminary results

TitleTrophodynamics of fish assemblages associated with a Caulerpa prolifera (Forsskål) meadow in a shallow semi-enclosed embayment: preliminary results
Publication TypeConference Proceedings
Year of Publication2011
AuthorsMaidanou, M, Koulouri P, Koutsoubas D, Dounas C
Conference Name5th European Coastal Lagoons Symposium (EUROLAG), 25-30 July 2011, University of Aveiro, Portugal
Conference LocationAveiro, Portugal
Keywordsmediterranean, semi-enclosed ecosystems
Abstract

Semi-enclosed coastal ecosystems are generally included in the highly productive systems of the world. These systems are often associated with macroalgal habitats characterised as heterogeneous environments with high structural complexity supporting a great variety of faunal relationships. Elounda Bay, situated in the north-eastern part of Crete Island (Greece), covers a total area of 6.5 km2 and communicates with the open sea through two narrow channels. The inner basin occupies a surface of 4.7 km2 with maximum depth of 8.7 m and is characterised by remarkable seasonal fluctuations of temperature and salinity. The seabed is covered by the green algae Caulerpa prolifera which forms a dense and continuous canopy. Seven field surveys were carried out over a grid of stations located mostly in the inner basin on a bi-month basis during the period 2006-2007. In each survey, physico-chemical parametres of the water column and the surface sediments were measured and analysed. For the study of benthic and pelagic macrofauna, a benthic sledge and plankton net were performed respectively. A total of 12,949 individuals belonging to 37 benthopelagic fish species were collected by using a beach seine fishing net. Stomach content analysis of the most important fish species, in terms of abundance and biomass, was further examined. Taxa composition, abundance and frequency of occurrence of their prey revealed significant seasonal changes. Data from the fish stomach contents were also compared with the available macrofaunal benthic and planktonic organisms. Preliminary results showed that the favorable natural conditions, prevailing in the study area, and especially the presence of the Caulerpa prolifera meadow - an important structuring element providing a great variety of ecological niches and shelter for larvae and juveniles - makes it an essential fish habitat for the north-eastern coasts of Crete.

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