5.3 Living resources

The lagoons in Greece are not all equally explored scientifically. More attention has been paid to the lagoons of Amvrakikos Bay (Nicolaidou and Karlou, 1983; Nicolaidou et al., 1985; Nicolaidou and Karakiri, 1989; Reizopoulou et al., 1998; Christaki and Gotsis-Skretas, 1990; Reizopoulou et al., 1996; Kormas et al. 2001; Lazaridou et al., 2002; Reizopoulou and Nicolaidou, 2004, 2007, 2008; Nicolaidou et al., 2006; Christia et al., 2011), Papas (NCMR, 2000; Reizopoulou and Nicolaidou, 2007) and the Gialova lagoon in the Peloponnese (Arvanitidis et al., 1999; Petihakis et al. 1999; Koutsoubas et al., 2000a,b; McArthur et al., 2000; Triantafyllou et al., 2000).

Different biological components of the Eastern Macedonian and Thrace lagoons, such as phytobenthos (Orfanidis et al., 2000, 2001a,b; Malea et al., 2003, 2004), zoobenthos (Kevrekidis et al., 1990; Gouvis and Koukouras, 1993, Gouvis et al., 1997; Kevrekidis, 1997; 2004;) and fishes (Koutrakis and Tsikliras, 2003) were also explored. An account of the available information on the main biological components of the Greek lagoons is presented in the review by Nicolaidou et al. (2005), while the available information on lagoon fisheries resources is summarized in the review by Koutrakis et al. (2007).

5.3.1 Flora

In the most confined lagoons, the most abundant phytoplankton genera are Rhodomonas sp. and Cryptomonas sp, whereas in lagoons with better communication with the sea, dominant species can be diatoms (e.g. Rhizosolenia fragilissima and Nitzchia closterium) and dinoflagellates (Scrippsiella trochoidea, Procentrum scutellum) (Christaki and Gotsis-Skretas, 1990; Nicolaidou et al., 2005). In semi-enclosed lagoons (e.g. Gialova in Peloponnese), dinoflagellates dominate and diatoms are restricted to marine channels (Dounas and Koutsoubas, 1996).
Benthic vegetation consists of a small number of species and associations. Characteristic are 3
species of the genera Gracilaria, Ulva, Chaetomorpha and Cladophora, whereas the most characteristic of Phaeophyceae is the species Cystoseira barbata. Their diversity varies seasonally and is higher during summer and autumn (Orfanidis et al., 2001b). The angiosperms recorded mainly belong to the genera Ruppia, Zostera, Cymodocea and Zanichellia (Orfanidis et al., 2001b; Nicolaidou et al., 2005; Christia et al., 2011).

5.3.2 Aquatic fauna

In zooplankton, copepods are the dominant group (Siokou-Frangou,1986), whereas in the inner parts of lagoons the zooplankton consists of brackish water species, such as Calanipeda aquaedulcis, Acartia latisetosa, A. clausi and Centropages kroyeri and invertebrate larvae of barnacles, molluscs, decapods and polychaetes (Nicolaidou et al., 2005).
Macrozoobenthos is the most studied ecosystem component in Greek lagoons (Nicolaidou et al., 1983; 1985; 2006; Reizopoulou et al., 1996; Dounas et al., 1998; Arvanitidis et al., 1999; Koutsoubas et al., 2000; Kevrekidis 1997; 2004; Kevrekidis et al., 2000; Reizopoulou and Nicolaidou, 2004; 2007).
The most abundant species are typical of euryhaline and eurythermic lagoons such as the molluscs Cyclope neritea, Abra segmantum, Mytilaster minimus, Cerastoderma glaucum, the polychaete Hediste diversicolor, amphipods of the genera Gammarus, Corophium and Microdeutopus, chironomid larvae and oligochaetes. The most important variable shaping species composition and benthic diversity is the degree of communication with the sea (Reizopoulou and Nicolaidou, 2004; Nicolaidou et al., 2005).
Concerning fish, more than 30 species were recorded from the Greek lagoon systems (Nicolaidou et al., 2005). These are typical lagoon species, which complete their whole life-cycle in lagoons such as Aphanius fasciatus and Atherina boyery; migratory marine/estuarine species such as Sparus aurata, Dicentrarchus labrax, Anguilla anguilla, Mugil cephalus, Chelon labrosus, Liza saliens, L. aurata, L. ramada, Diplodus sargus and Solea solea; and marine species that are normally distributed in the sea and are occasionally or accidentally found in the lagoons: e.g. Gobius spp., Blennius spp., Diplodus annularis, D. puntazzo, Lithognathus mormyrus and Salpa salpa (Nicolaidou et al., 2005). Most lagoons in Greece are used for the extensive culture of various fish, most of which are migratory marine/estuarine species.

5.3.3 Wildlife

The habitat types such as riparian floodplains, wet meadows and surrounding wetlands present a unique diversity of invertebrates, reptiles and amphibians. Thousands of migrating birds congregate in these freshwater marshes, which are a source of food and place of rest during spring migration. Many priority bird species such as Dalmatian pelicans, pygmy cormorant, ferruginous duck, bittern and lesser spotted and greater spotted eagles can be found in these ecosystems.