Vulnerability

STATE OF DECLINE

An estimated 26 million to 73 million sharks killed annually. (Clarke et al.,2006).

32% open water sharks are threatened with extinction/classified as Vulnerable, Endangered, and Critically Endangered (The IUCN Red List).

80% decline in shark numbers within the last 30-50 years, with some species like the oceanic whitetip and silky shark suffering more than 90% decline.

 

BIOLOGICAL SETBACKS

Sharks pups still in placental membranes. Most sharks are late to mature and have relatively few offspring, leading to their vulnerability to dramatic population declines.

Top of food-chain (apex) predators like sharks are not designed to reproduce in abundance. Unlike some fish species that can produce millions of eggs in a single spawning (E.g. The Ocean Sunfish is capable of producing up to 300 million eggs), the shark’s reproductive system models the mammals’ in that they:

  • Experience slow growth
  • Late sexual maturation
  • Long gestation periods
  • Small litter size

Case in point: Female basking sharks take 16 to 20 years to mature, gestate between 2.6 and 3.5 years and produce litters of only about 6 pups. There are also species like the dusky shark that do not reproduce until a year after the last birth.

At the present rate of commercial fishing, sharks clearly do not stand a chance in recovering their populations.

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