The effects of environmental stressors on gonad biomarkers of a sentinel marine bivalve, Mytilus galloprovincialis

ABSTRACT

The aim of this work is to investigate the effects of environmental stressors on male reproductive biomarkers in sentinel species of bivalves inhabiting Annaba estuaries, considered to be reservoirs receiving industrial, agricultural, and domestic discharges. Male Mytilus galloprovincialis were collected in four seasons from a non-polluted site (S1) and two other locations receiving untreated sewage (S2) and a mixture of contaminants (S3). Testicular sperm concentration, motility, velocity, the amplitude of lateral head displacement (ALH), the beat cross frequency (BCF), spermatozoan DNA fragmentation, and histological profiles were evaluated. Individuals from S2 and S3 have diminished sperm concentration, motility, velocity, ALH and BCF, along with a significantly increased spermatozoan DNA fragmentation that was much higher in S3. Testicular tissues demonstrated histo-pathological alterations in mussels subjected to anthropogenic activities during the four seasons. In conclusion, reproductive biomarkers of male mussels were both spatially and temporally variable, which is probably correlated to pollution types and the changing seasonal stressors.

KEYWORDS:

• Bivalves
• DNA fragmentation
• mussels
• reproduction
• sperm

Acknowledgements

The authors would like to thank local fishermen for helping in the collection of mussels. They are grateful for reviewers’ comments that improved the manuscript significantly.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project was supported by the Directorate General of Scientific Research and Technological Development (DGRSDT) for PhD students (grant number 02/2018) for the Laboratory of Animal Ecophysiology.