Wildlife officials are urging vigilance from ocean users as humpback whales return to Hawaiian sanctuary waters.

The Hawaiian Islands Humpback Whale National Marine Sanctuary says careful attention is particularly critical due to early reports of mother and calf pairs this season, which generally runs from November to May.

Thousands of humpback whales return to warm Hawaii waters during this time to breed, give birth, and nurse their young.

The sanctuary is reminding ocean users to maintain the legal distance of at least 100 yards from whales while in or on the water, and at least 1,000 feet when operating an aircraft.

Additionally, to avoid collisions, boat operators should keep a sharp eye out for whales and reduce speeds. These two key practices have been shown to reduce the risk of hitting a whale, especially calves, which are particularly susceptible to vessel strikes.

“By following regulations and recommendations, ocean users can reduce their impact on the animals and their habitat and also play an important role by helping monitor humpback whales in sanctuary and nearby waters,” said Ed Lyman, Sanctuary Natural Resource Specialist, in a news release. “By locating and reporting distressed animals and providing initial documentation and assessment of the animal — from a safe and legal distance — ocean users act like first responders and are the foundation of our conservation efforts,” he said.

The following is a rundown of guidelines:

>> Go slow, whales below

During whale season, especially in water depths of 600 feet or less, boaters are asked to maintain a speed of 15 knots or less to minimize the risk of striking a whale. When directly approaching a whale to view it, or departing from viewing, speed should be reduced to six knots or less within 400 yards.

>> Keep a safe distance

Collisions are a risk to both humans and whales. It is illegal to approach a humpback whale closer than 100 yards by any means when on or in the water, including by boat, kayak, and paddleboard, and closer than 1,000 feet by aircraft.

>> Report entangled whales

See an injured or entangled marine mammal? Report it immediately to NOAA’s marine wildlife hotline at 888-256-9840 or the U.S. Coast Guard on VHF channel 16. Entanglement can result in starvation, physical trauma and infections, and may contribute to vessel strikes since the animals are less mobile.

>> Report violations

To report a vessel approaching too close to a whale, contact the NOAA Fisheries Enforcement hotline at 800-853-1964 or respectwildlife@noaa.gov. You can also report violations via the DLNRTip app.