Sharks are present in Monterey Bay, which is recognized as a highly diverse and productive marine ecosystem. The bay’s unique geography and nutrient-rich waters support a variety of shark species. This area, which includes the Monterey Bay National Marine Sanctuary, is a regular habitat for sharks that live in or migrate through its waters.
Other Sharks Found in the Bay
A diverse array of other shark species are consistently found throughout Monterey Bay, making up the vast majority of shark encounters. These species are generally non-threatening to ocean users and represent a healthy population within the marine environment. The Leopard Shark (Triakis semifasciata) is one of the most common species observed, frequently inhabiting the shallower, warmer waters of the bay.
Many other pelagic species pass through or reside in the bay seasonally:
- Blue Sharks (Prionace glauca) are slender, open-ocean species that sometimes venture into the bay’s productive waters during the summer and fall.
- Salmon Sharks (Lamna ditropis) are often mistaken for smaller Great White Sharks due to their similar body shape, though they primarily feed on fish.
- The Pacific Angel Shark (Squatina californica), a flat-bodied species that resembles a ray, is a resident, spending its time camouflaged on the sandy bottom.
The Presence of Great White Sharks
The Great White Shark (Carcharodon carcharias) is a regular, seasonal presence in Monterey Bay, which falls within the northern boundary of the area historically nicknamed the “Red Triangle.” This region is known for its dense population of marine mammals, the primary food source for adult white sharks. Their migration patterns are closely tied to the seasonal abundance of prey, particularly seals and sea lions.
Adult white sharks typically return to the Central California coast in late summer and early fall after spending months foraging in the deep ocean, sometimes as far west as the “White Shark Café” halfway to Hawaii. They congregate in the area to feed on the colonies of pinnipeds, such as elephant seals and harbor seals, which haul out on the nearby coasts. This seasonal return is driven by the need to replenish energy reserves.
A more recent development is the establishment of a seasonal nursery for juvenile white sharks within the bay, particularly in the northern areas off Santa Cruz County. Traditionally, young white sharks (5 to 9 feet long) were confined to warmer waters south of Point Conception. However, a marine heatwave event around 2014, often called the “warm blob,” raised local sea surface temperatures, allowing these smaller sharks to expand their range northward.
These juveniles aggregate in the comparatively warmer pockets of water found in the north end of the bay between April and October. Their smaller body mass makes them vulnerable to colder temperatures. This area provides an abundance of their preferred juvenile diet, which consists mainly of fish, skates, and rays, before they transition to the marine mammal diet of the larger adults.
Why the Bay Is a Shark Hotspot
The concentration of Great White Sharks and other species in Monterey Bay is directly attributable to a unique combination of geographical and oceanographic features. The most defining feature is the immense Monterey Canyon, an underwater chasm that rivals the depth of the Grand Canyon, running nearly 60 miles out to sea. This deep-sea structure brings cold, nutrient-dense water close to the shore.
The canyon facilitates a process called upwelling, where deep, cold water rises to the surface. This influx of nutrients fuels a massive bloom of phytoplankton, forming the base of a highly productive food chain. The rich primary production supports dense populations of smaller fish and invertebrates, which in turn attract larger predators, including various species of whales, dolphins, and, significantly, the seals and sea lions.
The abundance of these marine mammals—California sea lions, harbor seals, and northern elephant seals—is the primary factor drawing the adult white sharks to the area. These pinnipeds are the preferred prey, and their colonies along the Central Coast provide a predictable and energy-rich food source. The cold, productive waters and the massive prey base create an unparalleled foraging ground, solidifying the bay’s reputation as a major gathering point for sharks.
Understanding Human and Shark Interaction
While the presence of Great White Sharks is well-documented, the occurrence of unprovoked attacks on humans remains statistically rare in Monterey Bay. Despite the bay falling within the Red Triangle, the frequency of such incidents is extremely low. This is partly because white sharks do not actively seek out humans, and bites are often attributed to exploratory behavior or mistaken identity, as surfers or kayakers can resemble a seal from below.
For ocean users like swimmers, surfers, and kayakers, awareness is the best form of caution. General safety guidance recommends avoiding areas where seals or sea lions are actively congregating or hauling out, as these are the primary hunting grounds. It is also advisable to avoid entering the water during low-light hours, such as dawn and dusk, when sharks are most active and visibility is limited. By understanding the environment and the animals’ natural behaviors, people can safely coexist with the diverse marine life in Monterey Bay.