HONOLULU (HawaiiNewsNow) - Fewer humpback whales appear to have made the annual migration to Hawaiian waters this winter.
The total number of whales that made the journey seems to be at its lowest level in at least five years, officials with the Hawaiian Island Humpback Whale National Marine Sanctuary said.
But they also warned against making conclusions based on the observations.
"A more robust and comprehensive survey throughout the main Hawaiian Islands is needed to determine the actual numbers of humpback whales that migrate here each season to mate and give birth, how long they stay, and what waters they use," Ed Lyman, resource protection specialist, said in a news release.
"Additionally, it is also important that we have a better understanding of humpback whale habitat use in other breeding areas and within the feeding areas for North Pacific humpback whales during the winter and spring months."
The sanctuary relies on the observations of its own scientists, plus whale counts conducted by volunteers and tour operators. Whale counts are conducted on one day each January, February and March.
The information is meant to provide a snapshot of the number of whales that migrated to Hawaii.
Whale season in Hawaii is November to May, with a peak in February and March. And this season, humpback whales arrived later than normal.
The sanctuary estimates that as many as 10,000 humpback whales use Hawaiian waters as their principle "wintering ground," migrating here to mate, calve and nurse their young. The population of North Pacific humpback whales is now estimated at 21,000, up from about 6,000 in the 1990s.
Lyman said another possible indication that fewer whales made the journey this winter was a decline in the number of whales in distress.
During the 2015-16 whale season, the sanctuary got five confirmed reports of whales entangled in gear. By comparison, in each of the previous two seasons, the sanctuary got reports of 13 whales in distress.
Sanctuary officials said while the population numbers are worth watching, they're not yet concerned that the North Pacific population of humpback whales is in sudden decline or necessarily affected by a new threat.