Recent shark attacks along the North Carolina coast have people thinking twice about going into the ocean.

Perhaps they should be thinking twice about going into sounds and estuaries.

Shark attacks in ocean waters are common-place. People expect sharks to be in those waters and not so much in sounds and estuaries. But sharks can be just as deadly or injurious in sounds and some rivers. Sharks don’t have maps that show them whether they are in the ocean, a sound or other body of water.

Rick Brass, dockmaster of Washington’s waterfront, has seen bull sharks in the Pamlico River. Roger Rulifson, an East Carolina University researcher studying sharks, said bull sharks, tiger sharks, black-tip sharks at Atlantic sharpnose sharks are shark species most commonly found in inland waters. By far, according to Rulifson, bull sharks tend to be more aggressive with people.

Charles Bagley, another shark researcher at ECU, believes the number of bull sharks in the Pamlico Sound might be increasing. Bagley contends that an increase in water temperatures and a thriving habitat may be reasons why mother bull sharks have baby sharks in the sound rather than in Florida waters.

In January, Katharine, a great white shark, was tracked during her journeys along the East Coast and in the Pamlico Sound. Katharine, classified as an immature shark, was tagged off Cape Cod on Aug. 20, 2013. Katharine was 14 feet, 2 inches long and weighed 2,300 pounds when tagged, according to OCEARCH, a nonprofit organization that tracks and researches great white sharks and other aquatic top-of-the-food-chain predators.

People should not fear going into ocean waters or other waters where sharks may be present. They should exercise caution, especially when there’s been recent shark activity in a specific body of water.

Following these tips to avoid a shark attack: always swim in a group, don’t wander too far from shore, avoid the water at specific times (night, dusk or dawn), don’t enter the water if bleeding, don’t wear shiny jewelry, avoid waters being fished and those with lots of bait fish in them and don’t enter waters where sharks are swimming.