Late Arrival of Humpback Whales (Megaptera novaeangliae)

Observation by Nikki Whittern:

On June 21, 2019 at noon, a local tribe member sighted the first glimpse of the whales this year. The member said that they saw a group of whales spouting in the water out near Eider Point, this is a common sighting spot for whales here in Unalaska. Usually we tend to see the sights of the whales much earlier than late June. Last year, the whales made their appearance early-mid May. This unusual delay of appearance sparks curiosity as to why the whales may have came later in the year compared to other years.

I have some speculation that it may have something to do with the climate change that we are experiencing in the Pacific. In an article published by NOAA called, “Humpback Whales are Navigating an Ocean of Change” written by Elizabeth Weinberg, she explains the effects climate change has on the whale population. She highlighted that the decrease in the whale population, which could possibly be connected to delay of whale appearance in Alaska, may be due to the climate changes that we are currently facing. Recently, the Pacific has experienced a variety of unusual warming water in the past few years. It started with The Blob, formed in 2013, which was an unusual mass of warm water in the Pacific Ocean off the coast of Alaska and Pacific Northwest, then the Pacific Decadal Oscillation in 2014 (which can be thought of as a long-term El Niño), and then the most recent El Niño cycle began in 2015. We know from research that the warming of the waters can be harmful to the krill population, as they are sensitive. “Krill eggs hatch at a narrow temperature range, and rely on strong upwellings bring nutrients into the surface area of the ocean. Warmer waters reduce the strength of these coastal upwellings, impacting krill production. That leaves humpback whales without their primary food source.” (Weinberg, 2018). With a shrinking krill population we may begin to see a shrinking whales population. And with a shrinking krill population in the Pacific, we may also see that whales may be reluctant to return back to Alaska with a diminishing food source.

Verene Gill, wildlife biologist with the Protected Resources Division of NOAA Fisheries, writes:

I suspect the forage fish were later which can vary from year to year. I haven’t been tracking the humpbacks much this year (focusing on belugas) but I know the ones in Seward were on time. But many of those come up from Mexico.

Darlene Holmberg, in Aniak, writes:

I'm curious to know if the marauding orcas intersect and affect the migrating whales! Do we track only orca? or are there other migrating whales that are tracked by satellite?

Comments from LEO Editors:

In the most recent Bering Sea Ecosystem Status Report (see attached documents for PDF of report brief), researchers found ocean conditions to be similar to the low-ice and above average water temperatures recorded in the early 2000s. Two figures below, provided by Rick Thoman at the Alaska Center for Climate Assessment and Policy, also show above average sea surface temperatures and low Bering Sea ice extent documented as of June 2019. During a survey in the summer of 2018, krill abundance was found to be low, following a trend first documented in 2012. Fluctuations in krill abundance has the potential to impact higher trophic level animals, such as whales, that depend on krill as a food source. Erica Lujan