Non-indigenous sea slug Tenellia adspersa in the southeast coast of the Arabian Sea, India

Abstract

The sea-slug T. adspersa was identified and reported here, which happened to the first of its kind from India based on the specimens collected from bar mouth of Cochin harbour (Lat. 9°58’N & Long. 76°15’E) at the depth of 5m on 13th September 2013. There were 17 specimens of T. adspersa collected in the area. Among these, juveniles ranging from 2.96 mm and adult specimens up to 7.8 mm were obtained. One of the important prey items for the T. adspersa is the hydroid Garveia franciscana, which was found in Cochin estuary.The details of the T. adspersa distribution records around the world are given in this paper. The intensive international shipping activity could have triggered the invasion of T. adspersa. Another way might have been through the egg masses of T. adspersa discharged through ballast water, which might developed into adult. In the present study, specimens were obtained from plankton to adult stage . Therefore, it might have been transferred through ballast water. Continuous monitoring of harbours/Port is very much essential to prevent the invasion of non-indigenous species.