Reproduction in Sharks

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Sharks invest a lot of energy into producing a few, well-developed young. Who have a good chance of survival.

Shark population have been falling sharply due to human activities. 16 out of 31 oceanic shark species are either critically endangered or endangered. To save this dwindling populations, scientists rely on sharks living in zoos and aquariums. They take help of these sharks to study reproduction among them. They build breeding programs for increasing the population and learn more about the conditions shark need to thrive.

In a new study, scientists undertook the largest effort to artificially inseminate sharks. This study itself resulted in 97 new baby sharks, including one whose parents live in opposite side of the country. Some of babies don’t have fathers at all.

For this experiment, scientists collected semen from 19 male white spotted sharks and used it to inseminate 20 females. To move the sharks from one aquarium to another is not only expensive but also troublesome and stressful for sharks also. But now we can move genes around through sperms.

Reproduction in Sharks: A Unique way!!

Shark reproduction is tricky. Many shark species have the ability to store sperms from mating encounters. These stored sperms they use to fertilize their eggs later. So the father is not necessarily the male, the mother most recently had contact with. To ensure that they were not using the stored sperms, females were monitored for about 6 weeks. Interestingly, some female sharks are capable of reproducing with no male at all, a process called Parthenogenesis. In this female create an embryo without relying on genetic material from male.

The offspring produced by parthenogenesis are always female in any species. Scientists believe this incredible phenomenon occurs when sharks get pushed into an evolutionary corner, for example in a male-less captive environment. Although it’s exciting to see that life finds a way to make miracles happen, there is a down side to this phenomenon too. There is a loss of genetic diversity and the resulting pups will be less equipped to fight off infections and deal with other challenges.