• UNF professor working to develop pregnancy blood test for sharks

    By: Katie McKee, Action News Jax


    University of North Florida professor Dr. Jim Gelsleichter has been researching sharks for more than 25 years, and is working to find a way to determine if they are pregnant through a blood test. 

    This is something that is difficult to determine in several species, according to Gelsleichter, but necessary to study their reproduction habits and patterns.

    He said sharks have a reproductive system that has several variables.

    Gelsleichter said sharks can have anywhere from one to more than 50 babies at a time, and some mothers carry them for nearly one year.

    He also said that many will only mate every other year, and being able to test for pregnancy would help learn their patterns.

    "It's important for us to maintain those populations and make sure they are healthy populations that we can sustain for years," Gelsleichter said.

    He said that he and his students go out off the coast of Northeast Florida three times a week, reeling in sharks and giving them ultrasounds. He said this is the best way to retrieve reproductive information without harming the sharks.

    "While it does work, it does have some limitations such as expense and the feasibility of just being able to ultrasound a large number of animals," Gelsleichter said.

    He said that ultrasounds only work if a female shark is far along in her pregnancy when the babies have already developed what they call a zipper, the cartilage in their backs that look like a spine.

    Gelsleichter said being able to detect pregnancy through a blood sample will allow them to receive results in the earlier stages.

    "One way that we do that we use the blood of sharks and detect the presence of reproductive hormones like you would find in humans," Gelsleichter said.

    He said those factors help determine if sharks are ready to mate or produce eggs, but doesn't detect pregnancy, so he has to research other factors. 

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