Larval fish assemblages in coastal waters of central Greece: reflections of topographic and oceanographic heterogeneity

Abstract

SUMMARY: Patterns in the mesoscale distribution of larval fish in the coastal waters of central Greece, an area of high topographic and bathymetric complexity, were analysed using samples collected during two ichthyoplankton surveys in July 1998 and June 1999. Salinities were lower in the eastern (Aegean) part of the study area due to the influence of waters originating from the Black Sea. In this region, larvae of many epipelagic and benthopelagic (typically summer spawning) species were less abundant in June 1999, when waters were significantly cooler, compared to July 1998. Multivariate analyses identified 'neritic' and 'pelagic' groups of stations dominated by larvae of epipelagic/bethopelagic (typically shelf dwelling) and mesopelagic species. In the west (Ionian Sea), a prominent third group of stations located in the deep and highly enclosed Korinthiakos Gulf was also defined with very high abundances of mesopelagic fish larvae. However, the genera Cyclothone and Vinciguerria that dominated the neighbouring offshore assemblage of the Ionian Sea were absent from this gulf. In the study area, Korinthiakós Gulf (>900 m) and North Evoikos (>400 m) Gulf comprise unique 'fjord-like' ecosystems in the Mediterranean with increased productivity and significantly cooler deep waters compared to adjacent open sea basins.

Spatial distribution of tuna larvae in the Gulf of Gabes (Eastern Mediterranean) in relation with environmental parameters

“…This fact may explain the broad distribution of bullet tuna larvae over the study area, since most of the bullet tuna positive stations were located over the Gulf of Gabes continental shelf, which is the widest part of the Mediterranean Sea (Burollet, 1979). Atlantic black skipjack larvae were considerably less abundant than bullet tuna in our samples, as also reported in other ichthyoplankton studies in the Mediterranean Sea (Garcia et al 2005b;Alemany et al 2010;Somarakis et al 2002;2011a). The confinement of Atlantic black skipjack larvae to the stations located between Kerkennah and Djerba Island which are characterized by low depths, may indicate that the spawners of the species tend to avoid open sea waters, showing a preference for stations over the continental shelf.…”

“…Mar. Sci., 14/1, 2013, 5-14 rhenian coastal waters (Cavallaro et al 1997;Piccinetti et al 1997), in the Ionian (Santamaria et al 1996(Santamaria et al , 2000Somarakis et al 2011a) and Levantine Kahraman & Alicli, 2007) Seas and in the Aegean Sea (Somarakis et al 2002;Isari et al 2008).…”

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“…Habitat-wise, the proportion of pelagic adult species was 61.1% epipelagic, 22.2% mesopelagic 11.1% and benthic 38.9%. (Somarakis et al, 2011) reported that in coastal waters of central Greece identified groups of the stations dominated by larvae of epipelagic, bentopelagic and mesopelagic species. Mesopelagic species also have a very low economic value, nevertheless, their abundance in the Mediterranean sea makes them the best-represented member of the deep water fauna they are the most common prey to other fish species (Olivar et al, 1998;Somarakis et al, 2002).…”

Autumn larval fish assemblages in the northwest African Atlantic coastal zone

“…Nevertheless, metamorphosis together with predation, that causes diff erential larval mortality between species within the assemblage, are the main factors leading to assemblage disruptions (Miller, 2002). Several studies have described the composition and spatio-temporal variation of larval fi sh assemblages, particularly in the Mediterranean Sea (Olivar et al, 2010;Somarakis et al, 2011a) and in the Canaries system (Moyano et al, 2009(Moyano et al, , 2014. On the Moroccan Atlantic coast, previous studies have focused on the horizontal eggs and larvae distribution of small pelagic fi shes (Ettahiri, 1996;Berraho, 2007).…”