Science from Bath Toys
by Curtis C. Ebbesmeyer
Twelve years and counting — the
saga of the tots’
tub toys continues. On January 10, 1992, 28,800 turtles,
ducks, beavers and frogs packed in a cargo container —
called Floatees by the manufacturer — splashed into
the mid-Pacific, where the 45th parallel intersects the
International Date Line (44.7°N, 178.1°E). During August-
September, 1992, after 2,200 miles adrift, hundreds beached near Sitka,
Alaska. Twelve years later, in 2004,
beachcombers were still ?nding the bath-time critters.
At Sitka’s second annual beachcomber fair held on
25 July 2004, Dean Orbison and son Tyler
exhibited a hamper full of 111 toys they’d beachcombed
nearby Sitka during 1993-2004. The basket held comparable
numbers: 18% turtles, 35% ducks, 26% beavers, and
21% frogs. During years at sea, the ducks and beavers
faded to white while the turtles and frogs remained original
blue and green, respectively. Animal bites and the surf
smashing them against rocks had ruptured many.
Through the years, Dean patiently recorded the date
and location where they found ninety of the fist-sized
Dean Orbison with turtles, ducks, beavers, and
After 12 years adrift, the frogs and turtles remained true-blue
to their original
colors (green and blue, respectively), whereas the ducks and beavers
yellow and red to white, respectively. Dorothy Orbison photo
This astonishing record
reveals peak recoveries in
five years with intervening gaps of 2, 4, 3, and 3 years,
i.e., 1992–1994–1998–2001–2004. Each year,
Tyler conducted comparable beachcombing effort so the
peaks in the time line are not the result of differing times
spent along the shore. The first peak occurred before
the Orbisons began recording, but a year in which other
beachcombers reported hundreds. We may safely assume
an initial peak in 1992, the year the playthings first
Jim Ingraham’s computer simulation of ocean surface
currents known as OSCURS (Ocean Surface CURrent
Simulator), provides an understanding of the peaks in
toy recoveries. OSCURS applies because its trajectories
around the North Pacifc Subpolar and Subtropical gyres have compared
well with those of many drifters, including
numerous satellite-tracked buoys, migrating salmon and a
sea turtle, many MIBs, several derelict vessels, hundreds
of Nike sneakers and hockey gloves, and the floatees.
After the tub toys first arrived in Sitka, flocks headed
west along coastal Alaska and the Aleutian Islands where
3,500 miles from the spill — hundreds invaded Shemya,
as reported by Chrystle White. Many continued
on westward to Kamchatka, Japan, then redoubled the
Pacific back to Sitka completing the 6,800 mile loop around
the Pacific Ocean’s northernmost gyre, the North Pacific
Subpolar Gyre (hereafter the Gyre).
OSCURS demonstrated the tracks the toys took,
rounding the Gyre to Washington, where Karen Gerber
and Verne Krause recovered a turtle and duck, respectively.
In the Queen Charlotte Islands, Guthrie Schweers found two turtles and four frogs. Remarkably, after three
years, all three beachcomber finds agreed with OSCURS
trajectories around the Gyre.
|Subpolar and Subtropical Gyres
of the North Pacific Ocean. Heavy lines, average drift
path; small arrows, local currents; dots, Great Garbage Patch.
Currents carry drifters along
the heavy lines around the Subpolar Gyre in three years, and around
the Subtropical Gyre in six
years. Flotsam may circulate in the Garbage Patch for half a century.
The Orbison data indicate that flocks of
toys completed four orbits of the Gyre. The first (2 years) may be
than the latter three (4, 3, 3 years), because the toys developed holes but continued
floating full of water buoyed
by the low specific gravity of their plastic.
Historic MIBs — Messages In Bottles — provide
confirmation of the Gyre’s orbital period as evident in the
Orbison time series. In the 1950s, into the Gulf of Alaska Canadian
hurled 33,869 MIBs in
12-ounce brown beer bottles. Twelve drifted around the Gyre in
1.9-4.2 years, matching the interval between the Orbison peaks
(2-4 years). The toys, plus MIBs,
provide twenty estimates, indicating the mean time to orbit the Gyre equals
2.9 years. As to speed, the mean orbital period equates to 6.9
miles per day over
the 6,800-mile course around the Gyre.
Dean and Tyler beachcombed an important contribution
to oceanographic science. The toys provide 40% of
the orbital period estimates and the MIBs the remaining
60%. How many more trips around the Gyre will the toys
make in future years? After four circuits, by mid-July 2004
Dean and Tyler found four toys; Kim Elliot located a faded
blue turtle. The Orbison data show numbers decreasing
six-fold in a decade from 25 in 1994 to four in 2004.
Prior to the Orbison data, OSCURS had suggested
that the Subpolar Gyre could trap flotsam like its neighbor
to the south, the North Pacific Subtropical Gyre, famed for
its Texas-sized garbage patch. In 2003, beachcombers found flotsam
half a century old — a rubber ball and two
glass fishing floats — which had been circling the Subtropical
Gyre for as many as eight circuits. The Orbison data
indicate flotsam wheeling round the Subpolar Gyre for up
to four circuits. I wonder if Floatees will appear through
five Gyre rotations, with a fifth peak anticipated in 2007?
What became of the thousands of toys beachcombers
never reported? Some, the surf buried and others spun
out of the Gyre. According to OSCURS, the currents
transported a number through Bering Strait into the Arctic
Ocean, where the pack ice conveyed them onward over the
North Pole into the North Atlantic Ocean. Bethe Hagens observed a duck in Maine (July 2003); and Sonali Naik observed a frog in Scotland (August 2003). These drifts
agree with a score of historic transarctic drifters, including
bottles, barrels, and plastic drift cards.
Other toys spun out of the
Subpolar Gyre south into
the Subtropical Gyre where Lucy Keith recovered a turtle
(Kure Island; July 1996), and Walt Pich reclaimed a beaver and frog
(Lanai Island; March 1997). Under the tropical
sun, many disintegrated to plastic sherds of the size displayed
by Richard Lang and Judith Selby on the cover of
this Alert. Ultimately, the toys will turn to dust, joining the
scum of plastic powder which rides the global ocean.
I thank Mary Ann and Larry Calvin for putting me up for a
week for the Sitka Beachcombers’ Fair, Larry for taking me
12 other scientists aboard the Morning Mist to beachcomb Fred’s
Creek, and Nancy Davis for thoughtful reviews of this article.
The Fair continues to be a major feature at the Paths Across
the Pacific Conference. The next meetings are scheduled in
Sitka for July 20-26, 2005, with the Beachcomber’s Fair held
Sunday, July 24. MIBs: Hollister, H.J., and A.J. Dodimead, 1962.
Canadian drift bottle releases and recoveries in the North Pacific
Ocean. Fisheries Research Board of Canada, Manuscript report
series (oceanographic and limnological) No. 141, October 22, 1962.
Statistical notes: time to drift around the Gyre equals
6,800 nautical miles divided by the speed between the drifter’s
start and ending observed time and position. Speeds between
start and end points: 20 estimates; mean = 6.93 mpd; standard
deviation = 2.06 mpd; coefficient of variation (standard deviation/
mean) = 0.30. Time to complete a single-circuit around
the Gyre (6,800 nautical miles): 20 drifters; mean = 2.93 years;
standard deviation = 0.86 years; coefficient of variation = 0.29;
95% confidence limits on the mean = ±0.40 years (there’s
certainty that the mean lies between 2.5-3.3 years); median = 3.0
years; range = 1.9-4.5 years.