Temporal patterns of larval fish distribution and abundance in a coastal area of northern Greece

Abstract

SUMMARY: Species composition, abundance and diversity of fish larvae were assessed in the Strymonikos and Ierissos Gulfs (northern Aegean Sea, Greece). Both gulfs are affected by the freshwater input of the Rivers Strymon and Rihios; water depth does not exceed 80 m. Samples were collected using a bongo net sampler (250 µm mesh size) over a grid of 35 stations in six cruises between June 1997 and May 1998. A total of 48 taxa of fish larvae (36 species, 5 genera and 7 families) were identified. The majority of identified fish larvae taxa consisted of demersal species that included larvae of Bothidae, Gobiidae, Callionymidae, Sparidae and Serranidae. The highest number of species occurred in the warm season (May, June, July, September) and this was attributed to the summer spawners that start their reproduction period during spring/early summer. The European anchovy (Engraulis encrasicolus) was the dominant species between July and September, and the European sardine (Sardina pilchardus) between November and March. Two distinct seasons (warm and cold) were identified by multivariate analysis, highlighting the importance of seasonality in shaping the community structure. The absence of well-defined larval fish associations revealed the importance of depth in the identification of different spatial patterns in an area.

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“…The importance of coastal ecosystem as spawning and nursery grounds for many fish species was well documented (Koutrakis et al, 2004;Azeiteiro et al, 2006). In this respect it might be expected that egg and larval abundance should increase with decreasing depth, however a significant relation between depth and ichthyoplankton abundance could not be observed in this study.…”

Larval fish distribution in shallow coastal waters off North Western Iberia (NE Atlantic)

“…This is probably due to the shallowness of the area, the horizontal environmental parameters homogeneity (namely temperature and salinity) and the limited contribution of river inputs (especially during the spring, summer and autumn months). Such a comparable pattern and the importance of the depth determining the taxonomic composition and abundance was also reported by Koutrakis et al (2004) in a shallow depth Mediterranean coastal area.…”

“…However, this study was conducted in a very specific area: very near to the coast (near to shore shallow area before the surf zone in the direction of the shoreline), associated with unique biological and ecological features (Harris et al, 1999;Hernández-Miranda et al, 2003). The higher fish larval densities and diversities were registered in the warm, high salinity productive months; such a pattern is well described in other temperate systems: Fourleague Bay, USA (Raynie and Shaw, 1994), Narrangansett Bay, USA (Keller et al, 1999) and Mediterranean Cadiz Bay (SW Spain) (Drake and Arias, 1991) and northern Greece (Koutrakis et al, 2004); also the low number of species and low diversity values in the winter months (with the higher values in spring-summer months) are usually reported from other systems (Shackell and Frank, 2000;Koutrakis et al, 2004).…”

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

“…In contrast to the western Mediterranean (Sabatés et al, 2007;Olivar et al, 2010) where larval fish assemblage studies have provided a comprehensive view of the link between oceanography and the structure of assemblages, multispecies investigations in the eastern Mediterranean are scant and restricted to the northern Aegean Sea (Somarakis et al, 2000(Somarakis et al, , 2002Koutrakis et al, 2004;Isari et al, 2008;Tsikliras et al, 2009) and the Sicilian channel (Cuttitta et al, 2004). In this paper, we present the findings of the first mesoscale study on larval fish assemblages that characterize the coastal waters of central Greece during summer (July 1998, June 1999.…”