Juvenile White Sharks On The California Coast

White sharks, also called great white sharks (Carcharodon carcharias), are one of the ocean's primary predators, and fascinating creatures to many. Yet white sharks remain one of the least understood of the sea's creatures, despite the enormous public and scientific interest in them. When white sharks are born, they are between 4 and 5 feet long. Sharks that are still juveniles mature at a length of roughly 10 feet. One of the ocean's top predators, adult white sharks have a length of roughly 21 feet.

Researchers track juvenile great white sharks in the Pacific Ocean using SPOT Tags. They discovered that every year, the sharks congregate in a secluded area close to the halfway point between San Diego and Hawaii. In this study, great white sharks are being tagged and their movements are being monitored by researchers at CSULB Shark Lab in Southern California, Monterey Bay Aquarium Research Institute, the University of Minnesota. By tagging sharks, researchers can learn where and how far they go, as well as whether more than one group is traveling down the coast.

Tags should be inserted in the muscle of the back, close to the first dorsal fin, at an angle toward the fish's head. The risk of the tagging procedure (to sharks and humans) is minimized through careful management and observance of animal ethics procedures and health and safety. Tags are used to monitor, track and locate sharks in their natural habitat. Tagging provides scientists with important information on life histories, population sizes, movement and migratory patterns.

SPOT tags are highly versatile, cost-effective satellite transmitting tags designed for tracking horizontal movements of free-ranging marine animals.

Short broadcasts are sent by SPOT tags to the Argos satellite network when they are on the surface. The transmitter's location is determined by adding up all of the signals that were received in a single satellite pass. Locations are accessible in almost real-time with up to 250 meter accuracy. The Argos system's global coverage enables the tracking of animals across great distances and in distant locations. One of the most popular marine satellite monitoring tags on the market, Wildlife Computers SPOT tags are frequently used.

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My map displays the observed locations of the sharks and their travel patterns along the west coast. Click on the multi-colored dots to view the coordinates, as well as the observed and bathymetry depths of each shark.

Observed Depth: The accurate depth measurement at each point where the sharks are seen.

Bathymetry Depth: The measurement between the shark under the water and the ocean floor.

Recording the depths of these sharks helps illustrate their traveling habits and their depths.

 Ocean currents  are also critically important to sea life. In addition to the bathymetry and observed depth, the oceans currents are also displayed. They carry nutrients and food to organisms that live permanently attached in one place, and carry reproductive cells and ocean life to new and different places. This map provides even more useful information when analyzing great white shark travel patterns within the Pacific Ocean.  Mass flows of water , or currents, are essential to understanding how heat energy moves between Earth's water bodies, landmasses etc.

The heat map analysis I performed on this dataset shows moderate levels of concentration of great white sharks in the Gulf of Santa Catalina. These sharks are fairly located towards the middle of the gulf rather than hanging tighter near the coast. There is also a larger portion of these sharks around the Catalina Basin and the islands as well.

The Gulf of Santa Catalina is also known for having sharks attack unsuspecting kayakers. A large great white shark attacked a  San Diego resident's kayak  as he was paddling off Santa Catalina Island and he was fortunate to escape unharmed. Sharks are not often known to attack humans, but when they do it is always transparent. This area has a somewhat high concentration of great white sharks, so the risk is higher.

Zoom into the map to see the oceanic landmarks the juvenile great white sharks tend to prefer to congregate towards. As seen above, the basins are surrounded by sharks. The sharks also either stray off farther from the coast or group in small areas around each basin closer to the shore.

The maximum and minimum depths reported demonstrate their migration patterns as well as their general feeding habits. Sharks that live in depths less than 984 feet (300 meters) are referred to be deep sea sharks. Previously, it was believed that these deep-dwelling species were less susceptible to overfishing than their cousins that lived on the surface, but new advances in deep-water technology have altered that belief. These sharks are believed to store a significant amount of oil in their massive livers to aid with buoyancy. Fisherman seek these sharks for their high value.

Sharks that tend to live on the more shallow end of the Pacific Ocean are very different from their deep sea brothers and sisters. The majority of sharks, though not all of them, have cold blood. Due to their ability to absorb heat from the sun, this makes them more likely to inhabit warmer waters. Given that shallow, shoreward seas are frequently the warmest, these areas become well-known hotspots for sharks. In the map I created, there is an equalized amount of both types of sharks.

They may be found in practically every type of ocean environment, such as the deep sea, the open ocean, coral reefs, and beneath the Arctic ice. According to the precise locations of the sharks in my map (and the geomorphology layer), they have gathered around the Santa Cruz and San Nicholas Basin, and inside the Catalina Basin. Some of the sharks even choose to gather in small groups within channels, but it is highly unlikely compared to those in the basins. Additionally, the sharks tend to avoid the Wyckoff Ledge and other landmarks with instances of protruding rocks.

According to the map above, the sharks are attracted most to shelf valleys, troughs, and plateaus. The locations where glacial erosion has created valleys, such as the poles, are where shelf valleys are most prevalent  (Hambrey, 1994; Anderson, 1999) . Non-glacial shelf valleys were primarily created by fluvial erosion during the Pleistocene ice ages when rivers flowed across what is now the submerged continental shelf, as well as by the erosive impacts of tidal and other ocean currents.

Due to their strong mobility as predators, juvenile great white sharks typically employ a continuum of habitats over the continental shelf, from the surf zone to the open ocean. Troughs are shallower versions of oceanic trenches. In addition to that, since great whites also travel along the seafloor at times, troughs are more ideal locations for them opposed to oceanic trenches and their deeper depth levels. They are less exposed to predators such as orcas, who reside in deeper waters, and have easier access to their preferred prey of fishes and rays.  Orcas  are usually found in deep waters and are very partial when it comes to shallower waters. Since they prefer cooler waters, they are less likely to attack juvenile sharks when they inhabit warm shelf valleys, troughs, and plateaus.

 Oceanic plateaus  are created by enormous eruptions from the head of thermal mantle plumes that are still developing and are rising to the surface. The juvenile great whites fluctuate towards these plateaus due to their relatively flat surfaces and abundance of prey. In the shallow coastal waters of temperate oceans, stingrays are regularly seen. They typically only move in reaction to the tide and are mostly inactive and partially buried in sand. Juvenile great whites seek out these rays as easy prey in these areas. Therefore, these features are ideal travel spots for them in their early years due to the convenience of them being both protection from predators and easier access to prey.

Young white sharks tend to travel to areas near the coast and islands near the coast. These sharks concentrate in moderately large groups, as seem in the provided maps, creating larger points within datasets. The general habits of the great white shark of inhabiting areas around the Pacific Ocean ties back into their traveling habits and where they are.

With the data collected within these maps, the sharks' travel patterns have clustered over specific seafloor features including: plateaus, valleys, and troughs. We can infer that these are ideal travel locations for the juvenile sharks due to their relatively shallow depths in comparison to other oceanic features, and the accumulation of fresh/warmer water within these areas. Additionally, these sharks feed upon small fish, smaller sharks, and manta rays, which are found in such areas with shallow water. Typically, these foods are found at the seafloor's bottom, making the seafloor a popular spot for juvenile white sharks to hunt within. Therefore, we can assume that the ample amount of prey, protection from predators, and warmer waters attract these juvenile sharks.

When looking at both the reported observed and bathymetry depths, we can infer the preferred living conditions of these Great White sharks on the West Coast as well as the current tides within those areas. Using bathymetric data, models are created that calculate the currents, tides, water temperature, and salinity in a certain area. With the knowledge of the sharks being present in these areas, improved calculated efforts can be made for their general survival and overall travel habits.