Featured Image Credit: Terry Goss via Wikipedia
By Eva Gruber
Most swimmers in Southern California might be a bit anxious to hear about a recent uptick in the numbers of white sharks swimming laps just offshore of popular beaches. However, there is no reason to be alarmed – these white sharks are babies, taking advantage of the marine region known as the Southern California Bight as a nursery where they can stay warm, safe, and grow strong and big.
This is great news because the white shark population had suffered serious losses and had been on the decline for decades. This is a successful result of conservation efforts by state and federal organizations enacting regulations going back 40 years.
Predators sit at the top of the food web, and damaging it at the very bottom level means those at the very top suffer the largest consequences. The white shark babies of the Southern California Bight suffered from a complex of problems – pollution, bycatch from gillnetting, and overfishing of their prey species.
Several decades ago the ocean suffered from a lack of regulations which allowed industries to dump their pollution into the ocean, and this severely affect the marine food web at all levels. Fighting environmental battles that deserve an entire book, organizations were able to get pollution regulations enacted, and this was a giant step in repairing the human-damaged marine food web.
Another crucial step was the state-wide banning of gillnet fishing and the banning of fishing for white sharks in 1994. Since 1994 marine biologists have documented growing white shark populations – a direct correlation of the enacted regulations. The white sharks, being at the top of the Pacific Ocean food web, in turn shape it. Since the enacting of the Marine Mammal Protection Act in 1974, seals and sea lions in California have also grown in number.
These pinnipeds are the primary food source for adult white sharks. Without white sharks, however, populations of seals and sea lions would outgrow their ecological limits and throw the whole food web into disarray. The white sharks act as a check on pinniped populations, culling weak and sick individuals and in turn making the marine ecosystem healthier.
This is all great news to environmentalists and marine biologists, but the shark-phobic public might take a little more convincing. For now the baby white sharks have no interest in the millions of swimmers and surfers, and this is a positive conservation story in an ocean of doom-and-gloom.