An endangered shark species was found to have reproduced asexually for the first time, according to a recent study. Parthenogenesis—also known as virgin birth—has been observed in 1,000 invertebrate species, including insects, and in 100 vertebrate species, including in lizards, crocodiles, and birds (see more, w/video).
Researchers studied two female Mustelus mustelus sharks (known colloquially as common smooth-hound sharks) in an Italian aquarium for 13 years—exceeding the three months the species has been documented to store sperm. Despite no access to males, the female sharks managed to give birth annually since 2020. Genetic testing has confirmed the shark offspring were genetically identical to their mothers, implying parthenogenesis, and not the result of long-term sperm storage.
Research into reproductive behavior may help inform conservation efforts for smooth-hound sharks, whose presence in the Mediterranean, eastern Atlantic, and Indian oceans is projected to decrease by 50% in the coming decades. Illegal fishing and overfishing are considered largely to blame.
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