What a Basking Shark Is and Where to Find It
The basking shark is the second-largest fish in the world, reaching lengths of 26 to 40 feet and weighing up to 5 tons. Despite its enormous size, it is a filter feeder that eats only plankton, not fish or people. You will find basking sharks in temperate ocean waters across the Northern Hemisphere — the Atlantic coast from Nova Scotia to Florida, the Pacific coast from California to Alaska, and around the British Isles and northern Europe. They appear seasonally, moving into coastal waters during spring and summer when plankton blooms are heaviest, then retreating to deeper water in fall and winter.
Basking sharks are slow swimmers, cruising at 2 to 3 miles per hour with their mouths open to filter water. Their dark gray or brown bodies, enormous dorsal fin, and habit of swimming near the surface make them unmistakable. They are not aggressive toward humans, but their size and the speed at which they move through shallow water can startle boaters and swimmers who encounter them unexpectedly.
Key Takeaways
- Basking sharks are harmless filter feeders that eat only plankton and pose no threat to anglers or swimmers.
- They appear in coastal waters from spring through early fall, with peak sightings in June and July when water temperatures warm.
- Basking sharks are protected under federal law in U.S. waters and cannot be kept, harmed, or intentionally approached.
- Sightings are most common off the coasts of Maine, Massachusetts, California, and the Pacific Northwest, where plankton concentrations are highest.
- If you see a basking shark, maintain a distance of at least 50 feet and report the sighting to your state's fish and wildlife agency.
Seasonal Patterns and Where Sightings Happen
Basking sharks follow plankton blooms, so their presence is tied directly to water temperature and food availability. In the Atlantic, they typically arrive in New England waters in late April or May, peak in June and July, and depart by September. The coasts of Maine and Massachusetts see the most consistent sightings, particularly around Cape Cod and the Gulf of Maine. In the Pacific, they appear off California and Oregon in summer, with occasional sightings as far north as British Columbia and Alaska.
The sharks move into bays and estuaries when plankton concentrations are dense enough to make feeding worthwhile. This is why sightings cluster around specific locations — the Bay of Fundy, the waters off Monterey Bay in California, and the coasts of southern England are known hotspots. If you are fishing or boating in these areas during peak season, a sighting is possible but still uncommon. Most anglers fish for years without seeing one.
Legal Protection and What You Cannot Do
Basking sharks are protected under the Magnuson-Stevens Fishery Conservation and Management Act in U.S. federal waters. This means you cannot keep one, harm one, or intentionally pursue one. The prohibition applies to all recreational and commercial fishing. If you hook a basking shark accidentally while fishing for another species, you must release it immediately and report the incident to your state's fish and wildlife agency within 24 hours.
Many states have additional protections. Massachusetts, for example, prohibits any intentional approach within 50 feet of a basking shark. California and Oregon have similar distance requirements. These rules exist because basking sharks are slow to reproduce — females give birth to only a few pups every few years — and populations have been depleted by historical hunting. Violations can result in fines ranging from several hundred to several thousand dollars, depending on the state and the severity of the offense.
How to Identify a Basking Shark at Sea
A basking shark is unmistakable once you know what to look for. The most obvious feature is the enormous triangular dorsal fin, which can reach 6 feet tall and is visible from a considerable distance. The fin is dark gray or black and stands nearly vertical. The shark's body is thick and robust, dark gray or brown on top and lighter underneath. The head is blunt and conical, and the mouth is enormous — up to 3 feet wide — but always open only when the shark is actively feeding.
At the surface, a basking shark creates a distinctive wake and often swims slowly in a straight line. You may see the dorsal fin and the top of the head breaking the water. The gill slits are large and visible along the sides of the head. A basking shark will never approach a boat or person aggressively; if one is near you, it is feeding on plankton and is unaware of your presence. The shark's eyes are small and positioned on the sides of its head, giving it poor forward vision.
What Basking Sharks Eat and Why They Are Harmless
Basking sharks are obligate filter feeders, meaning they eat only plankton — tiny organisms suspended in the water. They consume copepods, fish larvae, and other microscopic life by swimming with their mouths open and straining water through their gill rakers, which act like a sieve. A single basking shark can filter up to 2,000 tons of water per hour while feeding. They have no interest in fish, seals, or humans. Their throat is too small to swallow anything larger than a few millimeters, so even if they wanted to eat a person, they could not.
The only time a basking shark poses any risk is if a boat collides with one or if a person gets too close and startles the animal. A basking shark can injure someone with its tail if it feels threatened, but such incidents are extraordinarily rare. Most basking sharks you encounter will simply swim away or ignore your presence entirely. The shark's slow speed and predictable behavior make it one of the easiest large marine animals to avoid.
Reporting Sightings and Contributing to Research
If you see a basking shark, you should report it to your state's fish and wildlife agency or marine resource department. In Massachusetts, contact the Division of Marine Fisheries. In California, report to the Department of Fish and Wildlife. In Maine, contact the Department of Marine Resources. These agencies track sighting locations, dates, and numbers to monitor population trends and understand migration patterns.
Several research organizations also accept basking shark sightings. The Basking Shark Project, based in the United Kingdom, maintains a global database of sightings and uses the information to study movement patterns and population health. When you report a sighting, include the date, time, location (latitude and longitude if possible), water temperature if you have it, and the number of sharks you saw. A photograph is helpful but not required. Researchers use this data to understand where basking sharks go during winter and how populations are recovering from historical overfishing.
Basking Sharks and Other Fishing Activity
Basking sharks do not compete with anglers for food or space. They eat plankton; you are fishing for fish. Their presence does not indicate good or bad fishing conditions for your target species. If you are fishing for striped bass, bluefish, or other saltwater game fish and a basking shark swims nearby, it is coincidence. The shark will not interfere with your fishing, and you should not attempt to interfere with the shark.
Boaters should maintain awareness during peak basking shark season in areas where sightings are common. Reduce speed if you see a dorsal fin in the distance, and give the shark plenty of room to move. A basking shark can be injured or killed by a boat propeller, and collisions can damage boats as well. If you are operating a commercial fishing vessel, report any basking shark bycatch to your fisheries management authority immediately, as required by law.
Frequently Asked Questions
Will a basking shark attack a person in the water?
No. Basking sharks are filter feeders with no interest in hunting large animals. They cannot swallow anything larger than a few millimeters. There are no documented cases of a basking shark attacking a person. The only risk is if you deliberately provoke one or get so close that it feels threatened and uses its tail defensively, which is extremely rare.
What should I do if I hook a basking shark while fishing?
Cut your line immediately and do not attempt to land the shark. Report the incident to your state's fish and wildlife agency within 24 hours. Include the date, time, location, and any details about the encounter. Keep any photographs you took. This information helps researchers understand where basking sharks are feeding and how often they interact with fishing gear.
Can I get close to a basking shark to take a photograph?
No. Most states require you to maintain at least 50 feet of distance from a basking shark. Approaching closer is illegal and can result in fines. Even if it were legal, getting close can stress the animal and disrupt its feeding. Use binoculars or a telephoto lens to observe and photograph from a safe distance.
When is the best time to see a basking shark?
June and July are peak months for basking shark sightings in the Atlantic. In the Pacific, sightings are most common from June through September. Early morning and calm, clear days offer the best visibility. Sightings are still rare even during peak season, so do not expect to see one on every trip to coastal waters.
Are basking sharks endangered?
Basking shark populations were heavily depleted by hunting in the 20th century, particularly in European waters. They are now protected in U.S. and European waters and are recovering slowly. They are listed as Vulnerable on the IUCN Red List. Populations remain at risk because they reproduce slowly — females have only a few pups every few years — and they are still hunted in some parts of the world.