THE STORAGE OF SPERMATOZOA IN THE OVIDUCAL GLANDS OF WESTERN NORTH-ATLANTIC SHARKS

Spermatozoa stored in oviducal glands of sharks sampled off the North American east coast were revealed by viewing stained tissue sections using light microscopy. Of eleven species surveyed, sperm were found in nine: Alopias vulpinus, Lamna nasus, Carcharhinus obscurus, Carcharhinus plumbeus, Galeocerdo cuvieri, Prionace glauca, Rhizoprionodon terraenovae, Sphyrna lewini, and Sphyrna tiburo. Three insemination patterns are proposed to account for differences noted in these findings: (1) non-storage/immediate insemination for sharks such as Lamna nasus; (2) short-term storage/delayed insemination as found in sharks in which ovulation is prolonged over weeks or months such as Rhizoprionodon terraenovae, and (3) long-term storage/repeated insemination, a characteristic of nomadic sharks such as Prionace glauca and Carcharhinus obscurus which can store sperm in specialized tubules for months to years.