Hundreds of volunteers counted 191 humpback whales on Kauai, Oahu, Maui and Hawaii island over the weekend, but heavy rain and wind resulted in challenging sighting conditions.

Volunteers on Saturday collected data from 51 sites across the main Hawaiian Islands and logged 191 whale sightings.

That number was significantly lower — nearly half — of the number seen in February 2019, when there were 372 whale sightings from 55 sites across the main isles during the same 15-minute period.

For the second year in a row, volunteers from the Hawaiian Islands Humpback Whale National Marine Sanctuary Ocean Count collaborated with those from Maui’s Great Whale Count by the Pacific Whale Foundation so that data could be collected simultaneously for all four islands.

Pacific Whale Foundation chief biologist Stephanie Stack said due to poor visibility, its count was likely “an under-estimation of the number of whales present in Maui Nui” and that she believed there were more than what was counted on Saturday, including moms and calves.

Sanctuary officials said this was likely the case, as well, for Kauai, Oahu and Hawaii island.

The following is a breakdown of sightings.

>> On Maui, Great Whale Count volunteers collected data from 12 sites during 15-minute intervals between 8:30 and 11:50 a.m. From 8:30 to 8:45 a.m., Maui volunteers counted 53 whales. They saw the most whales — 70 — from 9:30 to 9:45 a.m., which was the most of any period throughout the day.

>> On Kauai, Oahu and Hawaii island, Ocean Count volunteers collected data from 39 sites and sighted 138 whales from 8:30 to 8:45 a.m., which was the most of any period throughout the day’s count.

Sighting conditions were challenging due to wind and heavy rain, and some sites canceled or dismissed counts.

Volunteers in January counted 279 whales from 53 sites on all four islands under mostly clear and sunny skies.

The purpose of the Ocean Count is to promote public awareness about humpback whales, the national marine sanctuary and shore-based whale watching opportunities. On Maui the annual Great Whale Count, one of the world’s longest-running citizen scientist projects, provides a snapshot of trends in the relative abundance of whales.

Besides tallying humpback whale sightings, volunteers document the animals’ surface behavior and note other species seen — which this time included spinner dolphins, sea turtles, Hawaiian monk seals and various seabirds.

“The economic benefit of citizen science is incredibly important to researchers, who can only collect a small amount of data themselves and are often facing budgetary restrictions,” said Stack in a news release. “By crowdsourcing data collection, researchers can learn much more about the natural environment than they can with individual effort.”

The volunteer counts take place in January, February and March, considered the peak of the humpback whale season in Hawaii. A third and last count is scheduled for March 28.

Volunteer sign-ups are available at oceancount.org or mauiwhalefestival.org/greatwhalecount.