By Blaise Jones

Many sharks occupy spaces near the top of their ecosystem’s food chain. This means that they are able to prey upon many different species of animal, while only a few can prey upon them. By hunting all the species below them on the food chain, sharks are able to help maintain healthy ecosystems.

Breaks in the Chain

Over thousands of years ecosystems have evolved into highly specialized structures. Each organism that lives in an ecosystem has a niche it fills; primary producers, herbivores, carnivores, or scavengers. Certain niches are big enough that multiple different species can fill them. Others are so specific that only one or two species fill it.

Sharks occupy one such tiny niche: the highest level of apex predator. The ecological niche of top apex predator is vitally important to the health of ecosystems, and if they are removed then it can lead to a total collapse of an ecosystem.

Opportunity Calling

When sharks hunt, they go for the easiest meal possible. This means they hunt the animals that are easiest to find and easiest to catch. Therefore, sharks focus on species with high abundance, and focus on the members of these species that can’t get away from them, namely the sick and old.

By removing the sick and the old fish from the ecosystem, sharks allow the younger fish to grow and reproduce by eliminating competitors, increasing genetic diversity of the populations. By removing the sick fish, sharks help control diseases and prevent infection from spreading from fish to fish.

Increased Biodiversity

Sharks encourage high levels of biodiversity in the ecosystems they inhabit by feeding consistently on the species with in the most numbers. By hunting the most abundant species, sharks allow the other species a chance to expand their populations. But when the first species population reaches lower numbers than the other species, sharks will stop focusing on them and hunt the other species.

Do Not Eat the Grass

Sharks don’t even have to hunt to regulate their ecosystems. Their presence alone is enough to keep certain ecosystems in check. Sea grass beds are sources of habitat and nurseries for many different species of fish. They’re also the primary food source for manatees and sea turtles. Manatees and turtles avoid the areas that sharks frequent, leaving the sea grasses to prosper. But if there are no sharks around, sea turtles and manatees will eat all of the sea grass, leaving dozens of other species without homes.

SOURCES:

http://oceana.org/sites/default/files/reports/Predators_as_Prey_FINAL_FINAL1.pdf

https://www.insidescience.org/content/threats-sharks-threaten-entire-ecosystems/1351

“The Encyclopedia of Sharks” by Steve Parker“Sharks: The Animal Answer Guide” by Gene Helfman and George H. Burgess

“Sharks: The Animal Answer Guide” by Gene Helfman and George H. Burgess