Ecological Gradients of Epimegafaunal Distribution along The Sectors of Gulf of İzmir, Aegean Sea

Erhan Mutlu

doi:10.46384/jmsf.985685

Abstract

During 2009-2010 epifaunal materials were collected seasonally with a beam trawl from seven fixed stations in the infralittoral of Gulf of Izmir to study spatiotemporal distribution of megabenthic fauna and their ecology. A total 153 megafaunal species were identified belonging to nine phyla, comprised mostly of 54 molluscans, 43 chordates (mostly fish), 20 arthropods, and 18 echinoderms. Nine alien species were recorded. Four species (two fish species, one gastropod and one Asteroidea species) were constant species and 16 species were common species in the study area. Lesueurigobius friesii, Buglossidium luteum, Turritellinella tricarinata and Astropecten irregularis were the most frequently occurred, and Lesueurigobius friesii, Varicorbula gibba, Anomia ephippium, Turritellinella tricarinata and Dentalium sp were the most abundantly occurred species. Excluding the evenness index, faunistic characteristics tended to increase as a factor of depth. Seasonal density (abundance and biomass) was minimal in April and maximal in February, followed by November having 2-fold higher abundance than that inJuly. Faunal assemblages were correlated with regions of the gulf and habitat type. Buglossidium luteum overspread the entire gulf excluding the inner gulf. Varicorbula gibba and Fulvia fragilis, a pollution indicator predominated the inner gulf. Hydrographical parameters and depth were associated to dictate faunal assemblages with difference among the sectors and habitats.

Highlights

Megabenthic communities are possible indicators to monitor anthropogenic impacts, or natural longterm alterations in marine ecosystems (Patania and Mutlu, 2021; Garuti and Mutlu, 2021)
Many studies have been carried out in the Mediterranean Sea to describe the spatio-temporal dynamics of Decapoda and megabenthic assemblages (Cartes et al, 2009; DeLaHoz et al, 2018; Koukouras et al, 2010)
Regarding to the ecological importance of the megabenthic fauna and the historical lack of comprehensive information on their distribution and ecology in İzmir Gulf, the aim of this study is to provide baseline information on bathymetric and seasonal distribution and biodiversity patterns of the megabenthic faunal assemblages in soft bottoms of the lower continental shelf, between 10 m and 50 m in the sectors having different trophic levels of the waters and sedimentary contents of a semi-closed gulf, Izmir Gulf under anthropogenic influences

Summary

Introduction

Megabenthic communities are possible indicators to monitor anthropogenic impacts, or natural longterm alterations in marine ecosystems (Patania and Mutlu, 2021; Garuti and Mutlu, 2021). Many studies have been carried out in the Mediterranean Sea to describe the spatio-temporal dynamics of Decapoda and megabenthic assemblages (Cartes et al, 2009; DeLaHoz et al, 2018; Koukouras et al, 2010). Most of these studies have been conducted in the central and western Mediterranean, as well as in Greek waters (Kallianiotis et al, 2020). Studies on the distribution and ecology of megafaunal assemblages in Turkish coasts of the Aegean Sea are generally lacking

Objectives

Methods

Findings

Conclusion