An Updated Checklist of Marine Flora on the Continental Shelf of Gökçeada Island (Northern Aegean Sea, Turkey)

Abstract

Abstract:The present paper aims to describe the marine flora occurring on the continental shelf of Gökçeada Island (North Aegean) based on the review of the long-term researches which provided qualitative information on many taxa including Cyanobacteria, Chlorophyta, Ochrophyta, Rhodophyta and Tracheophyta.Eight species (Polysiphonia brevearticulata, Ceramium codii, Gymnothamnion elegans, Spermothamnion repens, Lophosiphonia cristata, Hydrolithon cruciatum, Leathesia marina, Caulerpa racemosa) and one variety (Caulerpa racemosa var. cylindracea) recorded during the present study are the new records for Gökçeada Island. The new recorded species belonging to Rhodophyta were found as opportunistic-filamentous and crustose epiphytic forms on Posidonia oceanica leaf blades during the years 2009-2016. The presence of Caulerpa racemosa, the Mediterranean invasive algae and its dispersal around the island proves the ecological threat on the coastal ecosystem of the island due to the touristic boat achorings and bottom trawling.Rhodophyta had the highest number of species dominated the macroalgal composition with 178 species followed by the contributions of Ochrophyta and Chlorophyta and Cyanobacteria with 78, 64 and 25 species, respectively. As for the marine phanerogams (Tracheophyta) that contribute as key ecosystems to the biological diversity were recorded as 1% of the systematic groups in the region presenting three genus (Cymodocea, Posidonia, Zostera) but covering vast areas.After all the future goals of this research are to develop a checklist of marine flora along the littoral zones of Gökçeada Island (North Aegean) presenting the last biodiversity situation and a detailed herbarium collection for the museum of Istanbul University Gökçeada Marine Research Department.

Trophic partitioning between abundant demersal sharks coexisting in the North Aegean Sea

“…Nutrient-rich Black Sea waters play an important role in sustaining high biological productivity and fish stocks in the North Aegean (Stergiou et al ., 1997; Pethiakis et al ., 2014). Some parts of the area have been identified as important habitats for seagrass ( Posidonia oceanica ) meadows, especially in Saros Bay and the northern part of Gökçeada Island for Turkish waters and there are also some spawning and nursery grounds for small pelagic and demersal fish (Machias et al ., 2007; Öztürk, 2009; Güreşen et al ., 2015).…”

Current status (as of end of 2020) of marine alien species in Turkey

“…Ecosystem and biodiversity impacts. There has been a considerable range expansion of Caulerpa cylindracea towards the northern Aegean Sea [125], with an increasing trend of its abundance. The maximum and mean algal coverage were estimated as 60% and 20%, respectively, between depths of 1 and 45 m at Ayvalık Islands Natural Park [126], but recent surveys proved a drastic raise of its coverage, extending to 100% in several localities (pers.…”