Case Study: Boats and Manatees

Michael Williamson (
Mon, 25 Apr 1995 10:42:50

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Subject: Case Study: Boats and Manatees
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The following is reprinted from the May 1995 edition of ANIMAL PEOPLE.  (See
info note at end.)
"Full speed ahead
and damn the manatees!"
 ORLANDO,  Florida--Killing manatees at a record rate of almost two a week,
 boaters could extinguish the Floridan subspecies in the wild--if they keep
it up--before the end of the 20th century,  now less than five years away.
 More than 60 Florida manatees died during the first quarter of 1995,  twice
the rate of 1994,  when 192 manatees were found dead,  second only to the 206
deaths reported in 1990 among the 25 years that statistics have been kept.
 As in 24 of those 25 years,  the leading cause of death,  claiming exactly
60,  was being sliced or stabbed by power boat propellers,  prows,  and
keels.  That broke the 1989 record of 58 human-caused deaths,  53 of them
caused by boats.  Severe cold is the manatees' only other significant killer.
 The already ominous plight of manatees got rapidly worse after February 17,
 when Volusia County Judge John Roger Smith trashed the power boat speed
limits imposed in 1991 by the Florida Department of Environmental Protection
to safeguard manatees.   The DEP and the Save the Manatee Club asserted at
the time that they could win on appeal,  and could meanwhile go on enforcing
the speed limits--but it's been open season ever since.  By mid-March a study
of Brevard County boaters found that 25% were speeding right by the limit
 "The court finds the language defining slow speed so vague that a person of
common intelligence must guess at its meaning and may differ as to its
application,"  Smith wrote.  He also argued that the DEP is obliged to prove
that manatees actually inhabit areas where boat speed limits are posted,  and
should show cause why designated high-speed corridors shouldn't be routed
through the manatee protection zones,  as if the slow-moving sirenians could
be taught to avoid such corridors any more than oppossums can be taught to
stay out of busy streets.
 Smith's ruling aquitted DeLand Fish Camp owner Rick Rawlins,  charged twice
in 13 months for allegedly breaking the speed limit on the Hontoon Dead
River.  It had no formal precedential value,  but wise-use wiseguys across
the nation ballyhooed it on talk shows,  online forums,  and in print as a
signal victory over allegedly excessive regulation.  The finer points of law
got lost in the uproar.
 About one million power boats compete with manatees for aquatic
rights-of-way in Florida.  Even before Smith struck down the speed limits,
 just 11 of Florida's 67 counties had any limits in effect,  enforced
haphazardly by 283 Florida Marine Patrol officers plus 215 Florida Game and
Fresh Water officers--about one officer per 2,000 vessels.
 As unpopular as speed limits are with the boaters,  the alternatives are
less popular still.  One would be closing waters inhabited by manatees to all
boating.  That would cover the entire coast of the Florida peninsula plus the
Everglades corridor,  and would have no chance of acceptance even if someone
were to seriously propose it.  Another,  raised from time to time for 60
years,  would be mandatory installation of propeller guards.  Since only
about half of the manatees killed by boats are actually hit by the
propellers,  guards would reduce but not prevent deaths.  However,  the Miami
Herald reported on March 24,  "Boat manufacturers resist the idea,  claiming
that the guards hamper engine performance and speed.  Owners who do install
the protective devices often have ended up suing major manufacturers after
losing their engine warranty."
History,  biology
 Officially,  manatees have been protected since the eighteenth century,
 when England declared Florida to be a manatee sanctuary in an apparent
strike at Spanish smugglers and slave-traders,  who killed manatees by the
shipload for food.  The state of Florida adopted a manatee protection law for
the animals' own sake in 1893,  strengthened in 1907 with the imposition of a
$500 fine for killing or molesting one.  In 1907 money,  that fine was as
substantial as the $20,000 penalties imposed by the 1972 Marine Mammal
Protection Act and the 1973 Endangered Species Act.
 And it was just about as ineffective,  because then as well as now,
 virtually all human killings of manatees have been judged accidental.
 Found in dwindling numbers across the West Indies,  and once distributed
throughout the tropics,  manatees are slow breeders.  They reach sexual
maturity at age nine as a rule,  though some females may be capable of
reproduction at age five.  Bearing females produce just one calf every two to
five years,  after a 13-month gestation.  Cold snaps,  dangerous to all
manatees,  are particularly deadly to the young,  says Loren Fish,  who as
supervisor of animal care at Sea World of Florida in Orlando is responsible
for the largest group of manatees likely to survive--15 rescued from distress
situations and two born at the facility.
 "When the water gets below 68 degrees,  the young can't tolerate it,"  Fish
says.  "They develop pneumonia and stop eating."  Unusually cold weather
killed 53 manatee calves in 1990,  the same as the number of manatees killed
by boats that year--the only year that boat-related deaths didn't head the
list.  Fortunately the warm-water discharge areas around coastal power plants
provide temporary manatee refuges during routine cold snaps.  "These areas
are heavily monitored,"  Fish confirms.  Such monitoring revealed both bad
news and good news earlier this year.  The bad news,  in January,  was that
only 1,443 manatees were discovered,  one of the lowest counts on record.
 The good news was that 1,822 turned up in a February recount,  one of the
highest counts ever.  But the variance also told biologists that their margin
of counting error is so high that records showing the population is up from
about 800 over the past 20 years may only reflect improved if still imperfect
counting methods--not an actual increase in manatee numbers.  Instead,
 manatees could be holding even or further declining.
Captive breeding
 Manatees breed so readily in captivity that the U.S. Fish and Wildlife
Service forbade mingling of the sexes at captive facilities in 1991,  to
prevent overcrowding.  Yet restoring the wild population through captive
breeding is not yet a viable option,  despite a decade of attempts.  Miami
Seaquarium vet Jesse White in 1984 placed two captive-born manatees in
holding pens in the Homosassa River,  then released them in 1986,  after they
appeared to be capable of feeding themselves.  As of July 1990,  he told
People magazine,  "I believe they're still out there."  But because of a lack
of confirmed follow-up sightings,  U.S. Fish and Wildlife Service manatee
recovery coordinator Robert Turner has pronounced them dead.  Another
experimental release,  in Puerto Rico,  failed when the manatee starved to
 "It's like taking a pet and releasing it into the forest,"  Turner told
Craig Quintana of the Orlando Sentinel.  "They have no experience at all on
anything but romaine lettuce in a concrete tank.  When he ran out of lettuce,
 he didn't eat.  We just thought they'd start eating other vegetation."
 A related problem,  Fish adds,  is that "We don't yet know how they learn
their migration patterns."  If seasonal migration isn't instinctive,
 captive-born manatees might be caught too far north to survive when winter
weather hits.
 Formerly wild manatees are believed to do better.  Of about 135 ill,
 injured,  or orphaned manatees received at Sea World since 1973,  47 have
been returned to the wild,  including three who were released earlier this
year,  wearing tags and radio transponders monitored by USFWS via satelite.
 Hoping to improve the odds, Sea World and USFWS last summer set up a
$40,000,  4.5-acre "halfway station" for manatees in the Banana River,
between the Kennedy Space Center and Cape Canaveral.  The idea is to
acclimate manatees to their natural diet of sea grass before turning them
loose.  "Their weights are checked after one month,"  explains Fish.  "If
they've lost weight,  we keep them and try the release again later."  About
50 manatees,  currently distributed among five Florida stranding rescue
centers,  are considered potential release candidates.
Recovery plan
 The USFWS on April 6 proposed a second revision of the Florida manatee
recovery plan,  and extended the public comment period to June 5.  Persons
wishing to comment may obtain copies of the proposed revised plan from David
J. Wesley,  Field Supervisor,  Jacksonville Field Office,  USFWS,  6620
Southpoint Drive S.,  Suite 310,  Jacksonville,  FL  32216;  904-232-2580.
--by Merritt Clifton and Donna Robb
(ANIMAL PEOPLE is a nonprofit newspaper,  providing independent professional
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