Scalloped Hammerhead Shark


Reproduction and Life History


       The reproduction methods of the Sphyrna lewini is nothing out of the ordinary. Males and females reproduce sexually, leading to embryos in the female. Because there really isn’t anything outstanding about the reproduction of this species, there is not much information available on the subject.

      As I have state above, scalloped hammerhead sharks reproduce sexually and the product is a fertilized egg. Gestation usually ranges between 9 and 10 months with litters usually containing 12-34 pups (Duncan et al. 2006). There are not any known unique required specific conditions needed for reproduction.

       Once the litter is born, they are not raised by the parents. They are laid together in warm, shallow waters such as the bay or estuaries and form nurseries there until maturity (White et al. 2008). Maturity is measured differently for males and females. For males, it is when their claspers become fully calcified, which are just a segment of the abdomen found on males (White et al. 2008). Females are actually much larger in size at maturity. This is does make sense however, given that females typically reach maturity around the age of 15 years while males do around 6 years old (Myers et al. 2013). Their maturity determination is reproductive organ based, as in their uteri development (White et al. 2008). Once they do reach maturity, they go off shore and join schools of large numbers.

      The lifespan of the Sphyrna lewini is relatively short. Scientists have also had their fair share of debate over how long the average lifespan for this species really is. Because of this debate, there is a rather large range the average at 10-31 years of age(Myers et al. 2013). The debate and uncertainty exists because very few studies have been conducted on this particular topic.

Measuring Young-of-the-year Scalloped Hammerhead Shark, Sphyrna lewini

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