Reduction in reproductive activity from degeneration of testicular follicles in Megapitaria squalida (Mollusca: Bivalvia) exposed to metal pollution in the Gulf of California

• Published in: Marine pollution bulletin 2024-08, Vol.205, p.116648, Article 116648
• Main Authors: Yee-Duarte, Josué Alonso, Arellano-Martínez, Marcial, Roldán-Wong, Nefertiti Taydé, Kidd, Karen Ann, Ceballos-Vázquez, Bertha Patricia
• Format: Article
• Language: English
• Subjects: Bivalvia; Gamete resorption; Gulf of California; hemocytes; marine pollution; melanization; Melanized hemocytes; Metal pollution; Mexico; Reproductive dysfunction; Rosalia; Sperm cells; testes
• ISSN: 0025-326X; 1879-3363; 1879-3363
• DOI: 10.1016/j.marpolbul.2024.116648

Over a reproductive cycle, the prevalence and intensity of degeneration of testicular follicles in Megapitaria squalida collected from the mining port of Santa Rosalia (a highly metal-polluted area), and San Lucas (a less polluted site), Gulf of California, Mexico, were evaluated. At San Lucas, most individuals had a typical testicular structure, and degeneration of testicular follicles was present in 9.5 % of spawning organisms. In contrast, at Santa Rosalia, 68 % of males, mainly in the ripe stage, had testicular degeneration (72 % severe intensity, mostly in medium and large-sized). Degeneration was characterized by intense hemocyte infiltration, identified as dense masses with numerous melanized cells in the follicle lumen. In both sites, males with testicular follicles degeneration had a lower condition index compared to males without degeneration. Degeneration of testicular follicles before spawning compromises and decreases the reproductive activity of M. squalida males at Santa Rosalia, which may ultimately affect the population sustainability. Graphical abstract [Display omitted] •Long-term exposure to Co, Cu, and Pb can cause degeneration of testicular follicles•Hemocytes infiltration and melanization accompany testicular follicles degeneration•Males with degeneration of testicular follicles had lower condition index•Degeneration of testicular follicles reduces reproductive activity of M. squalida•Clams exhibits a reproductive resting and low gamete release in the polluted site