"Northbound gray whale photographed from our census observation station at the Point Vicente Interpretive Center on 31 January 2017."
— Alisa Schulman-Janiger

Spring migration 2017 already holds surprises. Unlike last season, the northbound migration did not start early. At the Gray Whale Census and Behavior Project near Los Angeles, CA, Director Alisa Schulman-Janiger reports:

"The migration is still in the southbound phase: The past few days we saw 28, 28, and 24 southbound grays! Our counts (from 1 December-12 February) are at 25 northbound and 983 southbound gray whales (including 64 newborns), compared to 75 northbound and 1299 southbound grays last season (2016) by this date. Last season our crossover (turnaround) date — when northbound exceeded southbound — was on 17 February: by that time, we had seen 105 northbound grays. Our crossover date will likely occur within the next two weeks."

Watch February's data to see what happens with this year's turnaround!

Think About It
Is the species that recovered after being endangered by overhunting now facing threats from climate change? Arctic sea ice levels are at record lows. The lack of ice in that region has allowed ocean temperatures to warm to levels well above normal. Air temps in the Arctic above 80 degrees N latitude have been much warmer than normal since roughly September 2016. Some thoughts scientists are pondering about changes in migration timing:

• The distribution and abundance of their primary prey, benthic gammarid amphipods, could be a factor. These crustaceans do not fare well in warmer seas (or with with salinity or acidity changes), and may not be doing well now. If less prey is available, it could be a major factor in gray whales needing to stay in the Arctic to spend more time foraging this season.
• Biologist Wayne Perryman once thought there was a very strong tie to the migration timing and Arctic ice coverage. Now he doesn't think that ice is a major factor in the southbound migratory timing. He feels comfortable in saying that the beginning of the feeding season in the spring is moderated by the timing of the melt of seasonal ice in May and June. However, several factors may impact the southbound movement. "We know that the whales are feeding farther north than they did a decade or two ago so they have farther to swim. Also, maybe there was a time when prey availability was more limited on these new grounds than it was before so it just took them longer to fill their tanks. And it may be that this is controlled by something that we haven't thought of yet."
• Is it possible that, despite an earlier ice melt and later ice formation, gray whales may be shifting back to a migration timing seen six seasons ago? Scientist Alisa Schulman-Janiger reminds us:

  "We had five years in a row of very early southbound migrations, including our five highest December counts in 33 seasons. This was NOT a "late" southbound migration: timing was more like the 'normal' that we used to see."

We will learn more over the next years as new data come in. The mysteries of migration are many!