On the mechanism of sperm release in three gobiid fishes (Teleostei: Gobiidae)

• Published in: Environmental biology of fishes Vol. 46; no. 3; pp. 321 - 327
• Main Authors: MARCONATO, A, RASOTTO, M. B, MAZZOLDI, C
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-07-1996
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gobiidae; Gobius niger; Knipowitschia panizzae; Marine; Vertebrata; Zosterisessor ophiocephalus; Mediterranean Sea; Adriatic Sea; MED; Brackish water environment; Reproduction; Vertebrata; Seminal vesicle; Spawning; Semen; Pisces; Interspecific comparison; Gobius niger; Fecundation; Breeding behavior
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/bf00005009

In fish, gamete release is commonly assumed to be synchronous in externally inseminating fishes. By collecting and counting the number of sperm and eggs released during separate matings in three demersal spawners, the mediterranean gobies, Zosterisessor ophiocephalus, Gobius niger, and Knipowischia panizzae, we observed that gametes are released asynchronously. Males release sperm before females start laying their eggs. Sperm is released in the form of sperm trails laid on the nest surface; subsequently active spermatozoa leave the trails and move in the water for several minutes. Sperm trails consist of bands of viscous material in which sperm is embedded. In most cases eggs are not laid directly over the sperm trail, suggesting that sperm may contact the eggs after the latter are released in the water. Male sperm duct glands, seminal vesicles, known to secrete mucosubstances, are likely involved in the production of sperm trails. The possible influence of this mode of insemination on the mating style of marine gobies is discussed.