Often unfairly and inaccurately cast in movies as the violent villain of the deep, sharks play a starring role in maintaining the health of their ecosystem. So much so that their absence would drastically throw their habitat and food web entirely out of whack.
As an apex predator, their top down regulation of prey species indirectly benefits the habitat quality and availability. For example, sharks eat sea turtles, sea turtles eat seagrass, and numerous animals use seagrass as habitat. If sharks are not around to regulate the sea turtle population, then seagrass beds become overgrazed, effectively demolishing habitat and nursery areas for several species of fish and invertebrates.
In other words, when sharks are present, they increase biodiversity in habitats as they prevent any one prey item from becoming too abundant. They also usually hunt fish that are slower and weaker, leaving the stronger, healthier fish to reproduce. This process can prevent the spread of devastating disease outbreaks and strengthen the prey species’ gene pool. All in all, the loss of keystone species and release of predator regulation over prey populations results in a ripple effect through the food chain, upsetting the balance of a marine environment. Humans have already caused a major decline in shark numbers, and this same thing can happen here in San Francisco Bay. What effect might the recent die off of hundreds of leopard sharks have on the Bay? What would happen to the sea lion population if there were no more white sharks patrolling the waters under the Golden Gate Bridge? One can speculate at the thought of these impacts on our Bay, or we can affect change through action. Here are a few things you can do to help our local shark species thrive in San Francisco Bay:
- Volunteer to restore Bay wetlands: Often referred to as the “lungs of the Bay” our local wetlands help improve the Bay’s water quality, naturally protect communities from sea level rise, and provides nursery habitat for sharks and other wildlife that call the Bay Area home. Register for a Bay restoration event near you today!
- Reduce pollution at the source: Our Bay’s keystone species (among others) need a trash-free Bay to thrive. That’s why we’re now pressuring Bay Area cities to eliminate the flow of trash from city streets into the Bay by 2022, but it will take all of us to accomplish this ambitious goal. Take time to organize or volunteer for neighborhood cleanups, urge your local officials to prioritize stormwater projects, and if you haven’t already take the Zero Trash Pledge!