Spatial patterns and temporal trends in the fisheries landings of the Messolonghi-Etoliko lagoons (Western Greek Coast)

Abstract

SUMMARY: The Messolonghi-Etoliko lagoon is one of the largest lagoon system in the northern Mediterranean coast. This area contains six clearly distinct lagoons with different topographic and hydrological features. The fishery landings of the lagoons are based on the ontogenic and seasonal migrations of the species. The total annual fishery landings of the barrier fish traps are estimated as 195 mt and are mainly composed of 16 species belonging to 8 families. Eel (Anguilla anguilla), the four species of Mugilidae (Liza saliens, L. aurata, L. ramada and Mugil cephalus), the two species of Sparidae (Sparus aurata and Diplodus annularis) and one species of Mullidae (Mullus barbatus) represent more than 92% of the total annual landings. The composition of the fishery landings varies between lagoons. The cluster analysis showed three groups of lagoons. The first group comprised lagoons in which the landings were dominated by eel, the second group was dominated by Mugilidae species and S. aurata, and the third by L. ramada and M. cephalus. The diversity index of the fishery landings is fairly constant in time, except for the Etoliko lagoon, where repeated anoxic crises decreased the diversity index value to almost zero in 1992. All the landing series showed a dominant annual cycle. Two seasonal patterns of the fishery landings were observed and linked to the fish spawning behaviour and/or their reaction to environmental forcings. The first one concerns species caught from summer to early autumn and the second pattern concerns species trapped during their autumn to winter offshore migration.Key words: Mediterranean lagoon, fisheries landings, fish diversity, spatial pattern, seasonal fluctuations. RESUMEN: VARIACIONES GEOGRÁFICAS DE LA PRODUCCIÓN PISCÍCOLA DE LA FORMACIÓN DE MARISMAS DE MESOLOGI-ETO-LIKÓ (GRECIA OCCIDENTAL). -La formación de lagunas de Mesologi-Etolikó es una de las reservas naturales marinas más grandes de la franja septentrional del Mediterráneo. Este conjunto está compuesto por seis distintas marismas, con diferentes características topográficas e hidrográficas cada una de ellas. La producción piscícola de las marismas se basa en los movimientos estacionales de las especies hacia el mar. Del estudio del trampeo se concluye que los movimientos migratorios equivalen a 195 toneladas y se componen principalmente de 16 especies las cuales pertenecen a 8 familias: anguila (Anguilla anguilla), cuatro especies de Mugilidae (Liza saliens, L. aurata, L. ramada, y Mugil cephalus), dos especies de Sparidae (Sparus aurata y Diplodus annularis) y una especie de Mullidae (Mullus barbatus). Estas especies representan más del 92% de los desplazaminentos anuales. Estos varían entre las distintas marismas. El análisis cluster distingue tres tipos de marismas. El primer grupo incluye las marismas cuyos movimientos son principalmente de anguila; el segundo grupo de Mugilidae y de S. aurata, y el tercero con movimientos sobre todo de L. ramada y M. cephalus. Los desplazamientos de estas especies presentan un ciclo anual...

Length–girth relations of fishes from a Mediterranean lagoon system

“…LGR is seasonally influenced by factors such as food availability, feeding rate, gonad development, and spawning frequency (Santos et al 2006). Thus, the estimated relations should not be considered as mean annual values, as the samples were collected during the offshore species seasonal migration (June to January: Katselis et al 2003).Girth measurements are positively and linearly related to total body length (e.g., Karpouzi and Stergiou 2003) a fact that is in accordance with the LGR reported here. All species have shown a steeper relation for maximum, rather than for opercular girths, which is mostly occurred for such relations (e.g., Mendes et al 2006), apart for few exceptions (e.g., Liza abu (Heckel, 1843): see Jawad et al.…”

“…Keywords: fish girth, fish morphology, barrier traps, Mesolonghi-Etolikon lagoons, Greece In the majority of the Mediterranean lagoons (Cataudella et al 2015) fisheries exploitation is conducted using permanent fishing devices made of reinforced concrete, the barrier traps that are installed at the interface between the lagoon and open sea. Fisheries based on seasonal on-going migrations of fry and adult fish species for spawning, foraging, and shelter between open sea and lagoons (Franco et al 2010) during June to February (Katselis et al 2003). The multispecies nature of the lagoon fisheries, which in turn implied the exploitation of numerous species with different growth, maturity, behaviour, and body shape are increasing the uncertainty on the determination of gear-specific efficiency.…”

Length–weight relations for 29 fish species from Homa Lagoon, Aegean Sea, Turkey

“…Fish swim through a V-shape entrance into the trap and pass through a few sections as far as the final chambers, from where they are taken our with dip nets. As Katselis et al (2003) reported, one of the most important types of exploitation is to use of barrier traps to catch fish during their seasonal or ontogenic offshore migration. The lagoon is an important nursery area and constitutes the fish feeding ground and therefore the local fishery benefits from fish migration related to feeding and reproduction.…”

Zooplankton diversity and distribution in a deep and anoxic Mediterranean coastal lake

“…The Messolonghi-Aitoliko lagoon complex is one of the most important Mediterranean lagoon systems in terms of size, fish production and ecological value (Katselis et al, 2003). It is located on the coastline of Central Greece and covers a total area of 15000 ha (Fig.…”