Out of over 450 species of shark in the world, about 200 are considered endangered by the International Union for Conservation of Nature (IUCN). More than 100 shark species are commercially exploited by humans, which further contributes to their endangerment. In fact, some populations of shark species have declined by over 90% in recent years, due largely in part to human activities.
The top ten most endangered sharks, from least to most endangered, are:
- the Borneo shark, Carcharhinus borneensis
- the whitefin topeshark, Hemitriakis leucoperiptera
- the dumb gulper shark, Centrophorus harrissoni
- the daggernose shark, Isogomphodon oxyrhynchus
- the striped dogfish, Mustelus fasciatus
- the angel shark, Squatina squatina
- the New Guinea river shark, Glyphis sp. nov. C
- the Bizant river shark, Glyphis sp. nov. A
- the Pondicherry shark, Carcharhinus hemiodon
- the Gagnes shark, Glyphis gangeticus
One of the primary threats to endangered sharks is overfishing. Many of the most endangered sharks are overfished, including the whitefin topeshark, the daggernose shark, and the Bizant river shark. Sharks are commercially in demand for their fins and cartilage. In parts of Asia, shark fin soup is considered a delicacy, while many believe shark cartilage to have health benefits, including fighting cancer, healing arthritis, and boosting immunity. These claims are currently unsupported by strong scientific evidence, however, so many sharks may be dying in vain.
Another factor that threatens many endangered sharks, including the whitefin topeshark and Bizant river shark, is the destruction of habitats. Mangroves are underwater coastal areas that many shark species typically use as breeding grounds. They are areas of vegetation along coastlines, and may be thought of as underwater forests. In many parts of the world, humans are destroying mangroves to make room for aquaculture, or the farming of aquatic species. As a result, many sharks do not have a place too breed, and the fact that they have low reproductive rates to begin with only worsens the problem.
Sharks are being killed at a much higher rate than they can reproduce. In general, sharks take many years to reach sexual maturity and typically give birth to few offspring at a time. If they continue to be slaughtered at the current rate, some species are expected to become extinct within the next decade. For example, populations of the dumb gulper shark have declined by 99% in recent decades, and it is possible than fewer than 250 individuals exist in both the New Guinea and Bizant river shark species. As of 2010, conservationists and shark advocates said critical and immediate action must be taken on behalf of endangered sharks to ensure their survival.