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E
very California diver I know has a
recent story about when they first
noticed things were changing at our
local dive sites. Some recall their local
kelp bed looking thin, while others
mention the presence of yellowfin
tuna on every shore dive, the range extension of a
Mexican nudibranch or the appearance of a skinny
baby sea lion on the swim step of their dive boat. For
me it was when a 9-foot-long smooth hammerhead
shark curiously bumped my camera rig. It was August
2014, and it was no secret that the surface waters were
a few degrees warmer than normal.
On that day the swell and wind were formidable,
but we were determined to get offshore. We hoped to
get a good look at the hammerhead sharks — typically
a subtropical species — that had been spotted at the
surface by one or two multiday dive boats over the
past few weeks. We couldn’t believe our luck when
one showed up and interacted closely (at times, very
closely) with us for three hours.
Among divers the rumored cause for the oddities
of the summer of 2014 was El Niño
(the warm phase
of the El Niño Southern Oscillation), an ocean-
atmosphere interaction in the east-central equatorial
Pacific that strongly influences ocean conditions
and weather patterns. However, the U.S. National
Oceanic and Atmospheric Administration (NOAA)
had not confirmed the presence of El Niño
conditions.
Meanwhile, Washington state climatologist Nick Bond
had already come up with an alternate name for the
odd patch of warmer-than-usual ocean off the coast of
the Pacific Northwest: “The Blob.” This phenomenon,
thought to be the result of locally persistent high
pressure that inhibited normal wind-driven oceanic
upwelling and cooling, had spread along the West Coast
and encompassed multiple stretches of ocean from
Alaska to Mexico.
In some places the ocean’s surface was 5°F warmer
than usual. Although the Blob quickly replaced El Niño
as the established cause, 2014 diving and fishing reports
in Southern California confirmed the effects, each more
bizarre than the last. Tuna fishermen came back from a
day offshore east of Catalina Island with images of a whale
shark. The lush, iconic kelp of Catalina and San Clemente
islands dwindled, and in some places this enabled prolific
growth of
Sargassum horneri
, an invasive alga that better
tolerates warmer water. A GoPro video of a manta ray,
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WINTER 2016
WATER
PLANET
A PERFECT STORM OF WARM
Text by Allison Vitsky Sallmon, DVM; photos by Andy and Allison Sallmon
Unusually warm surface waters in
California have made it easier to
interact with uncommon creatures, such
as smooth hammerhead sharks.