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D I VE SLATE
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FALL 2016
I
was in a small boat about 30 miles offshore
of San Diego, Calif., looking for life. We
were running hard at 20 knots when out of
the corner of my eye I caught a glimpse of
a tiny patch of brown against the vast blue
background. It was a bit of kelp about the size
of a trashcan lid. I turned toward it and immediately
saw a huge splash and a distressed yellowfin tuna doing
tight circles around the kelp. Here was a picture I had
wanted for years: a tuna on a kelp paddy.
When I got into the water I saw what had made that
big splash as the form of a massive 400- to 500-pound
blue marlin materialized out of the blue. The lightbulb
went off immediately, and I knew why the big marlin
was there — the more commonly seen striped marlin
does not prey on 20- to 30-pound tuna.
That day I got images of the blue marlin and the
tuna (see Parting Shot,
Alert Diver
, Winter 2015).
These were likely the first-ever underwater photos of
a blue marlin taken in California waters. It was among
the two or three best days I have ever had in 35 years
of diving kelp paddies.
That happened in the fall of 2014, which was the
beginning of a series of warming years that included
the very powerful 2015 El Niño. The warming events
of 2014, 2015 and 2016 have brought to the California
coast warm-water species from the south that had
rarely been seen over the years, and all of them were
observed around kelp paddies.
WHAT IS A KELP PADDY?
Searching for photographic subjects in the big blue
void of the open sea can be frustrating. Signs of life
are fleeting. The subtle splash of a marine mammal or
working birds are among the few signs that indicate
the possibility of life.
Much like the Atlantic coast, which has its own
drifting algae habitat (
Sargassum
), the Pacific coast
of North America has drifting kelp. Giant kelp
(
Macrocystis
) grows from Alaska to central Baja
California. Kelp paddies form when the anchoring
kelp holdfast weakens and breaks free after storms,
warming events or grazing by sea urchins. As the
80-foot-tall plants drift away, they become entangled
with other kelp plants. Buoyed to the surface by gas-
filled bladders, these floating masses are then swept
out to sea by wind and currents. An average-sized kelp
paddy might be the size of a bathtub, but they can
be more than 50 feet across with holdfasts dangling
down 40 feet. Kelp paddies can be found any time of
the year with locations varying from just a mile or so
off the coast to hundreds of miles out to sea. Most
kelp paddies drifting off the California coast originate
from the beds of giant kelp in the Channel Islands or
elsewhere along the West Coast.
Best described as “drifting islands of life,” kelp
paddies provide a refuge for planktonic fishes and
invertebrates that initially settle in the ready-made
habitat. Small fishes and invertebrates attract
schooling baitfish such as sardines and mackerel.
Larger predators such as tuna, marlin, sharks and
marine mammals complete the food chain as they
come to feed on the baitfish. The entire range of
large pelagic predators found on the Pacific coast
can be seen near kelp paddies. When the larger
predators appear, juvenile fishes can retreat within the
protection of the tangled plant mass.
The assemblage of animals found in association
with kelp drifting off the Pacific coast cannot be
found anywhere else in the world. For example, the
juvenile stage of the splitnose rockfish (
Sebastes
diploproa
) has only been observed under drifting
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KELP PADDIES
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22
DAN BOARD OF DIRECTORS
|
25
PATENT FORAMEN OVALE
AND FITNESS TO DIVE
|
28
DAN MEMBER PROFILE
|
30
PUBLIC SAFETY
ANNOUNCEMENT, EDUCATION SPOTLIGHT
|
31
TRAVEL SMARTER
KELP PADDIES
ISLANDS OF LIFE ADRIFT IN THE OPEN SEA
Text and photos by Richard Herrmann