Morphometric characteristics of invasive species Magallana gigas (Thunberg, 1793) in Bandırma Bay, Marmara Sea

Türkiye’s seas are the scene of the spread of invasive species in the entire Mediterranean basin due to the marine transportation of alien species and intensive aquaculture activities. In order to protect the natural ecosystem and track invasive species’ effects, these species must first be accurately identified and their distribution areas specified. The alien species, Magallana gigas (Pacific oyster), has introduced along the Turkish coasts. This study was carried out to determine the morphometric characteristics of Magallana gigas in the Bandırma Bay-Balıkesir between November 2013 and October 2014. Shell length varied between 68.08 mm (February) and 93.14 mm (April) during the year. Shell height was measured at the lowest 41.90 mm in February, and the highest 59.46 mm in June. Shell width was 35.80 mm in November when the study started, and it decreased gradually and reached its lowest value in February. W/L relationship of M. gigas was calculated as W=0.411×L2.653(R2=0.064) This study includes knowledges on morphometric relationships for the Pacific oyster which is crucial for the management of fisheries, aquaculture activities and native species (Ostrea edulis).