Investigation of Imposex in a Marine Gastropod Tibia curta (Sowerby II, 1842) at Gadani Ship Breaking Yards
Investigation of Imposex in a Marine Gastropod Tibia curta (Sowerby II, 1842) at Gadani Ship Breaking Yards
Seharish Munawar and Nuzhat Afsar*
ABSTRACT
Imposex is a well-known phenomena that has been documented over more than fifty years (50) in several marine gastropod species world around. The Phenomenon of imposex is directly connected with toxicity of tributyl (TBT) contamination and the source of this contamination is shipping traffic due to the use of TBT-based paints on ship hulls and the leaching of content into the water column. So, during the present study specimens of Tibia curta (Sowerby II, 1842), collected and investigated for the planned study from Gadani ship breaking yards (25.0361° N, 66.7136° E) which is the third largest ship dismantling site across the globe. Specimens were procured for a period of February 2019 to October 2021 in different intervals from the four selected sites along the Pakistan coast. Imposex was recorded only in the specimens of Gadani. The intensity of Imposex determination was based on the presence of and psudopenis and VDS (vas deferens sequence) in imposex female individuals. Imposex remained promising onlyat Gadani where imposex intensity was found 100% in females as when compared to other three sites. Whereas 1 to 4+ Vas deferens sequence (VDS) stages were observed in imposex females. Therefore, studies revealed the presence of imposex phenomena in targeted species at Gadani due to high concentration of leached out organometalic compound Tributyltin Tin (TBT) from the ship breaking scrap which is responsible to change hormonal levels and subsequent physiological change related to sexuality in animals as well as also responsible to bring morphological changes in other body parts like antenna and eye spot of affected individual.
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