Volunteers counting humpback whales near shore saw a normal amount of whale activity in January and February compared with the same period last year, according to the Hawaiian Islands Humpback Whale National Marine Sanctuary.

On Saturday from 8 a.m. to 12 p.m., an average of five whales were seen every 15 minutes from sites on Oahu and Kauai. Those on the Big Island saw an average of four.

The figures aren’t precise enough to scientifically estimate Hawaii’s humpback population, but they help in understanding population trends and corroborate scientific research, sanctuary officials said.

About 800 volunteers at 62 sites on the three islands gathered the data.

The figures are similar to data from a count in January.

The Pacific Whale Foundation conducted a separate count from Maui.

Ocean count project manager Claire Kavanaugh said the sanctuary doesn’t release an overall number of whales counted because of the chance volunteers might have counted some whales more than once.

Scientific studies have shown that Hawaii’s humpback whale population has been increasing at an annual rate of about 7 percent.

As many as 12,000 North Pacific humpbacks visit Hawaii waters each year to mate, calve and nurse their young.