Endangered small tooth sawfish (Pristis pectinata) in Florida are capable of reproducing via parthenogenesis, or without male sperm. Often called virgin birth, it is more often found in reptiles, birds and many invertebrates.
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The endangered smalltooth sawfish can give birth without male sperm. Photo by Florida Fish and Wildlife Conservation Commission
Researchers have documented evidence of seven sawfish living in two Florida rivers that were conceived without male sperm. They report their findings in the June 1, 2015 issue of the journal Current Biology.
According to the Miami Herald, Andrew Fields, a Stony Brook doctoral student was performing DNA fingerprinting of the fish to determine if they were interbreeding when he found that five of the fish appeared to be siblings, which is generally considered rare in parthenogenic births as offspring are usually produced one at a time.
Fields and his colleagues examined 190 fish in Florida’s Caloosahatchee and Peace rivers and found that many were closely related. Relatedness on a scientific scale is measured from 0 to 1 , with 0 indicating no relation, 0.5 indicating parents were full siblings, and 1 indicating virgin birth, or parthenogenesis. Seven of the 190 fish examined had a relatedness scale of 1, Fields said.
After the study was concluded, the fish were released back into the waters in which they were caught and were studied for six months before the tracking devices fell off. Fields hopes to catch one in the future to determine if it is growing and if it is reproducing normally.