Journal of Environmental Biology

Study on a new mechanism of sterilization in imposex affected females of tropical marine neogastropod, Thais sp.

Ferdaus Mohamat-Yusuff ^1,2*, Syaizwan Zahmir Zulkifli^1,3, Tsuuguo Otake¹, Hiroya Harino⁴ and Ahmad Ismail³

¹International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, 2-106-1

Akahama, Otsuchi, Iwate 028-1102, Japan

²Department of Environmental Sciences, Faculty of Environmental Studies, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

³Department of Biology, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

⁴Department of Biosphere Sciences, School of Human Sciences, Kobe College, 4-1 Okadayama, Nishinomiya, Hyogo 662-8505, Japan

*Corresponding Author E-mail: ferdius@upm.edu.my

Publication Data

Paper received:

29 September 2012

Revised received:

28 June 2013

Re-revised received:

05 August 2013

Accepted:

19 August 2013

Abstract

The morphological expressions and histopathological analysis of the gonads of a tropical marine neogastropod species (Thais sp.) from East Malaysia revealed new evidence of mechanical sterility in the imposex affected females. The gradual development of imposex was classified into five stages (Stage 0 to Stage 4) with three types of sterility conditions; Type A caused prohibition of copulation and capsule formation; Type B prohibits the releasing process of eggs; and gonads in Type C are infertile.? Further analysis is needed to confirm, if the gonad malformation in imposex affected snails is generated specifically by tributyltin (TBT) or by other possible factors. The levels of imposex incidence (stages and percentages) were greater in a marina and decreased with increasing distance from the marina. Organotin tissue burden across the sexes showed that dibutyltin (DBT) as well as TBT might be the elements inducing imposex in Thais sp. from Miri in East Malaysia.

Key words

East Malaysia, Imposex, Organotin, Sterility, Thais sp 

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