Subject: gray whale migraton

Nancy Stevick (
Tue, 1 Jun 1999 21:16:53 +0100

On  01 June 1999 11:57, Noelle wrote:

>    We are a group of 14-year-old students from Raffles Girls' School,
>(Singapore)and we are currently doing  project on gray whale migration.
>We are wondering if El Nino has had any effect whatsoever on their
>route. Last year, which was a El Nino year, their migration was found to
>slightly delayed. Is El Nino the reason? If you have anything that can
>be of use
>to us, please email me as soon as possible.
>Thank You.

Dear Noelle,

That is a good question -- one which many marine biologists would like to be
able to answer.  El Nino may affect many animals' habits, but proving that
changes were actually caused by El Nino is difficult.  There are just too
many factors to measure.

We don't know for certain what triggers whales to migrate.  Some scientists
theorize that length of day is the most important cue.  Others think that
changes in water temperature stimulate whales to migrate.  Different species
probably use different cues.  Since we don't know what triggers gray whales
to migrate, we are unable at this time to determine if El Nino is the cause
(or one of the causes) of last year's delayed migration.  This year, the
numbers of gray whales migrating along the west coast of the U.S. are lower
than normal.  We could speculate that El Nino has affected this population,
but we really don't know what has caused the decrease in numbers.

I'm sorry that I could not give you a more positive answer.  Given the
tremendous research being done on El Nino, we might be able to show a cause
and effect relationship in the near future.

Here are some web sites that have information on gray whales and El Nino.
Perhaps they can provide you with some additional theories.

* ACS Gray Whale Census and Behavior Project

* Channel Islands National Marine Sanctuary

*JourneyNorth Gray Whale Migration Reports

* National Marine Mammal Laboratory

* Cascadia Research

* National Ice Center

* Sea ice analysis, 5-day sea ice forecast, and sea surface temperatures

* Current SSM.I Sea Ice Analyses

* Historical Sea Ice Atlases

* National Weather Service, Alaska Region

* Southwest Fisheries Science Center

Good luck with your research,

Nancy Stevick