NUMBER 41 APRIL 2004
IN THIS ISSUE: - AMAZONIAN MANATEE CATCH
STATISTICS RE-EVALUATED
(p. 3)
- STATUS OF DUGONGS IN THE
AND
DUGONG STATUS REVIEWED
Helene Marsh, Helen Penrose, and
Carole Eros have recently published a comprehensive assessment of dugong
“status, threats, and research and conservation actions in 37 countries and
territories” throughout the species’ range, “based on published information and
the expert opinions of about 100 scientists and managers. These people were
contacted by email … between 1997 and 2001 as part of the process leading to
the development of a global status and action plan for the dugong….” The principal conclusions of this survey deserve
repeating: “On the basis of the largely anecdotal information supplied to us …,
we have evaluated the prospects of the dugong[‘]s
surviving throughout its range and tentatively conclude that:
·
it is at risk of extinction
in
·
its prospects are uncertain
in the
·
its prospects are probably
reasonable in the
·
it is probably secure in
For
the details, see: Marsh, H., H. Penrose, and C. Eros. 2003. A future for the
dugong? In: N. Gales, M. Hindell, and R. Kirkwood
(eds.), Marine mammals: fisheries,
tourism and management issues. Collingwood, CSIRO Publishing: 383-399.
(This well-produced, multi-authored hardback volume is available for AU$145.00
from CSIRO Publishing,
SIRENIAN
STATUS WORKSHOP IN 2005
The status assessments of the living sirenian species provided in the IUCN
Red List are due for revision by 2006.
A workshop to re-evaluate these species’ status, and decide what changes in the
assessments may be needed, will be convened by the IUCN Sirenia Specialist
Group at the 9th International Mammalogical
Congress (IMC9),
TETHYTHERIA
SYMPOSIUM IN 2005
Also at IMC9, synergistically with the above workshop, there will be a
symposium on “Tethytheria: Recent Taxonomic and
Natural History Findings”, which will cover work on the Proboscidea, Sirenia,
and Desmostylia, both living and extinct. If you are interested in
participating in the Sirenia-Desmostylia portion of the symposium, please
contact Dr. Norihisa INUZUKA <inuzuka@m.u-tokyo.ac.jp>.
ABSTRACTS OF 2003 MARINE MAMMAL CONFERENCE
As those who attended can attest, the 15th Biennial
Conference on the Biology of Marine Mammals, held in
LOCAL
NEWS
New
Amazonian Manatee Captive Birth. - A new baby manatee has been born
at the Aquatic Mammal Lab of INPA,
The calf went straight to the surface to breathe;
records of the sounds revealed that mother and calf were
vocalizing all the time. He started feeding about 5 hours after birth. Both
mother and baby are fine. - Vera
M. F. Da Silva
How Many Manatees Really Were Killed in
The most recent and relevant period of commercial
killing extended from 1954 to 1973, when the main manatee product in Amazonian
commerce was fresh meat. For interpreting these statistics, Domning (1982) used
a somewhat arbitrary conversion factor of 40 kg of usable meat per manatee
carcass. This was a low estimate based on the statement of Carvalho
(1967: 26-27) that a manatee normally furnished 40-60 kg of meat excluding fat.
However, Carvalho cited no actual data to support
this statement.
Recently, two of us (Kendall and Orozco), working in the Colombian Amazon, have collected
relevant data in the course of interviewing manatee hunters. These data point
to higher meat yields per carcass, and hence significantly smaller numbers of
manatees killed in the past, than Domning (1982) estimated.
Three former manatee hunters, who have
killed more than 120 animals among them, gave the following categories for size
of the manatee compared to meat yield (without fat or bone):
Length approx. 200 cm: 60-90 kg of meat (young
adult)
Length approx. 250 cm: 100-130 kg of meat
(full-grown adult)
Length approx. 280 cm or more: 120-180 kg
of meat (large manatee)
They agreed that there could exceptionally be animals
yielding up to 200 kg.
Some specific size/yield
figures from hunter interviews done over the last 4 years are as follows:
190 cm – 35 kg
190 cm – 60 kg
200 cm – 90 kg
approx. 250 cm – 80 kg
250 cm – 110 kg
250 cm – 130 kg
300 cm – 120 kg
300 cm – 180 kg
300 cm – 200 kg
Clearly, these estimates
vary a lot. The hunters say that this is typical; animals yield very different
amounts of meat and fat according to their condition. (They say that an average
adult will yield about one lata or one and a half latas of fat, maybe even two for a big animal. One “lata”, or can, traditionally holds about 20-25 kg.) Also, people are often not too accurate in
their measurements. We have not had the opportunity ourselves to accurately
measure the meat obtained from a carcass as it was being butchered. Our work
(Kendall and Orozco) aims to reduce hunting, and we consider we would be
delivering a contradictory message if we were present during or soon after a
hunting event to solicit data. However, it would be useful for anyone in a
position to do so to collect such data (from manatees or dugongs), in order to
increase the accuracy of the conversion factors used with old statistics.
As a rough guide to the size/age structure
of 55 animals hunted, 23% were up to 150
cm in length, 51% from 150 cm to 250 cm; and 26% over 250 cm in length (Orozco,
2001). The size distribution of animals hunted has probably changed
considerably in recent years because of the use in the Puerto Nariño area of
fishing nets that are more likely to trap smaller animals. Also, fishermen say
there are fewer really big animals than there used to be when they were young.
However, if we take 200 cm as
roughly the length of an “average” Amazonian manatee taken by hunters, then
even a conservative estimate places its expected meat yield closer to 80 than
to 40 kg. This would cut approximately in half Domning’s
(1982) estimates of many thousands of manatees killed between 1954 and 1973.
Really large manatees, possibly more frequently taken in the past, could easily
yield twice as much again, in the neighborhood of 160 kg.
In
contrast, Domning’s (1982) estimates of comparably
high numbers of manatees killed for their hides between 1935 and 1954 were
based on a conversion factor of 20 kg/hide, derived from data in Pereira (1944)
that included total numbers and weights of hides recorded in five consecutive
years (1938-1942). These numbers would
seem to be more firmly based than Carvalho’s (1967)
estimate of meat yields.
If, then, we accept the figure of some
6,300 manatee hides exported from the State of Amazonas, Brazil, alone in the
peak year of 1940, and halve the 1954-73 estimates based on meat, the resulting
picture (cf. Domning, 1982: fig. 1) more convincingly depicts a significant
decline in the take after 1940, with some apparent recovery in the take around
1960 followed by still further decline. This pattern, no doubt, is at least
partly an economic artifact, with the decline in hide production in the 1940s
and early 1950s driven by demand and linked to the new availability of
synthetic substitutes, and the sudden peak in meat exports in the late 1950s
possibly due to newly available refrigerated transport. The subsequent decline
may reflect real depletion of the population.
Whatever the correct interpretation,
however, we now think the estimates of 6,000-7,000 Amazonian manatees killed
for meat per year circa 1960 are erroneous and should be reduced by at least
half. Likewise, Domning’s (1982) estimate of commerce
in meat from up to 25 Antillean manatees on the northeastern coast of
References
Carvalho,
J.C. de M. 1967. A conservação da natureza
e recursos naturais na Amazônia
Brasileira. Atas Simpos. Biota Amaz.
7: 1-47.
Domning, D.P. 1982. Commercial exploitation of manatees Trichechus in
Orozco, D.L. 2001. Manatí Trichechus inunguis: Caza,
percepción y conocimiento
de las comunidades
- Daryl Domning (
A Preliminary Assessment of the Status and
Conservation of the Dugong (Dugong dugon) in the Lagoon of
Between 1999 and 2003, 12 opportunistic dugong
sightings were recorded by the Service des Pêches et de l’Environnement Marin (SPEM)
and the association MEGAPTERA Océan Indien. The largest group size was 3 individuals, last
sighted in 2000. Dugongs were observed associating with Indo-Pacific bottlenose
dolphins (Tursiops aduncus) in 1999, and a mother-calf
pair was observed in April 2000. The most recent incident was on
74% of
fishermen interviewed had observed a dugong at least once, 3% had heard of but
had never seen one and 23% had never heard of a dugong. Respondents, especially
elders, confirmed that before the early 1980s, one or two dugongs were sold at
the market of Mamoudzou every week and dugongs were
relatively abundant at that time. However, they were now said to have become
increasingly rare. Observations were made most frequently inside the 1,100 km²
lagoon. Other important areas highlighted by respondents included: Sada and
adjacent areas; the
Aerial
surveys (focusing on turtles) were conducted during 2002 and 2003 from a
micro-light aircraft. In 2002,
dugongs were observed on 12 occasions between August and September. These
included a group of 5-7 individuals and two mother-calf pairs which were
observed off the west coast near the
Between 2000 and 2003,
divers observed dugongs on 8 occasions. All sightings were of
single animals on the east
of the island, where the main dive sites are located.
The
results indicate that dugongs are present in small numbers within the lagoon
waters of
The
main threats to dugongs in
(NOTE:
For detailed coverage of manatee matters in
Marine
Industries Manatee Symposium Transcripts Available. – On
The symposium participants included: Dr.
Lemnuel Aragones, University of
Dissertation
on Manatee Protection in
Based in part on
extensive interviews with participants in these conservation efforts, this is a
valuable contribution to the historical documentation and sociological
understanding of events still unfolding, and the roles of some key individuals still
active in the manatee science and protection communities. Of particularly
contemporary relevance are Goedeke’s views on the
decline of the spirit of interagency cooperation since the 1990s; the primacy
of Federal over State regulation of manatee protection having been
“irrevocably” regained as a result of the lawsuits in 2000; and the likelihood
that the influence of scientists on manatee policy will continue to decline relative
to that of managers.
Dr. Goedeke can be contacted at <tlg017@yahoo.com>.
Manatee Hotline Connects to Wrong
Wildlife. - For
years, the Florida Marine Patrol advertised a toll-free number so callers could
report injured and dead manatees,
boating violations, illegal dumping and other problems. When the patrol was
absorbed into the new Florida Fish and Wildlife Conservation Commission five
years ago, the number changed. But the old 800 number lives on, posted
throughout
Starting in October, callers trying to
report an injured manatee using
the old 800 number were referred to another 800 number, which turned out to be
a sex-talk line called Intimate Encounters. A woman's voice promised a chat
with "fantasy girls" in exchange for a credit card.
"That's not the kind of wildlife
violation they respond to," quipped Suzanne Tarr
of the Save the Manatee Club, which is replacing its old signs with new ones
showing the new number.
One irate caller eventually got hold of
state wildlife biologist Penny Husted. "She was
very upset," Husted said. "She said a lot
of people are not going to go through the trouble she went through to report an
injured manatee."
This is not the first time Intimate
Encounters has turned a hotline into a party line. It has taken over old
toll-free numbers from the conservative journal Policy Review, the World
Wildlife Fund, Alltel's wireless customer service and rape crisis lines in
Tom Pitchford of the wildlife agency's
Florida Marine Research Institute said he could not figure out how Intimate
Encounters would attract paying sex-line customers from people reporting dead
animals.
Agency biologists had urged their bosses
to hang onto the old number because it was so well known, he said. Before the
sex-line connection, callers to the number got no answer, which also prompted
complaints, he said.
Being hooked up to a sex line "only
adds to the levels of frustration felt by our field staff and FWC dispatchers, it's making us look really bad to the public," Elsa Haubold, in charge of the marine institute's manatee program, wrote in an e-mail to
agency officials.
The agency kept the 800 number for four
years after the demise of the Florida Marine Patrol, noted Major Kent Thompson
of the wildlife agency's law enforcement division. Until July, callers to the
line got a recording referring them to the new number. Then, the company that
owns the 800 listings apparently sold it to Intimate Encounters, he said.
Now, Thompson said, "we want to see
if we can get that number back again."
The situation had agency spokesman Henry
Cabbage shaking his head. "You've got to admire the American spirit when
it comes to figuring out a way to make a buck," he said. "We're just
geniuses at that."
The correct toll-free number to
report problems to the Florida Fish and Wildlife Conservation Commission is 1-888-404-FWCC. - Craig Pittman (
First Birth
of Twin Sea Cows in Captivity. - A zoo
in central
The manatees came into the world on
November 4, at the Beauval ZooParc
in the town of
He said each of the arrivals weighed
around 20 kg (45 pounds) and were around a meter (three feet) long. One, a
male, was named
In the wild, the sea cows they are
descended from are found in brackish rivers in the southern
Death of Dugong at
Dugong Workshop. - A workshop on “The
Biology and Research Methods of Dugongs” was held on
- Kana Aketa, Ph.D,
Research Scientist, Japan Wildlife Research Center, 3-10-10, Shitaya, Taito-Ku, Tokyo 110-8676, Japan (tel.: +81-3-5824-0967; fax: +81-3-5824-0968; e-mail: <kaketa@jwrc.or.jp>)
Churaumi Aquarium Manatee Baby Named
After the baby was born, the question of
what to name it naturally arose. The management at the Aquarium finally decided
to ask for help from the public and organized a vote among visitors to the
facility.
A total of 5,247 people sent their
suggestion by postcard, and the baby was finally named
There were 93 manatee sightings reported to the state between 1995 and 2003,
compared with only 20 from 1929 to 1994, Louisiana Natural Heritage Program
zoologist Ines Maxit said
during an environmental law seminar at Tulane Law School, New Orleans, on 3
April 2004.
The manatees, more likely to be seen in
Maxit said it's unclear whether the number of manatees is increasing, or whether
people are simply becoming more aware of the unusual animals. However,
officials say scientific surveys point to an increase in the population of manatees throughout the
Louisiana has begun posting signs saying
"Manatee area, proceed with caution," with the phone numbers for
reporting sightings -- -- (225) 765-2821 or (800) 442-2511 -- -- in marinas in
the Lake Pontchartrain area, but many have been
stolen, probably as souvenirs, Maxit said. Her office
also has begun a program to educate boaters to avoid destroying seagrass, in
part through the issuance of "Manatee Sea Grass Beds" certificates.
The state also has entered into a contract
with the Audubon Aquarium of the
Rehabilitation
of a Manatee Calf (Trichechus manatus) in
Chetumal, Quintana Roo, México. - On Sunday, 14 September 2003,
staff of El Colegio de la Frontera
Sur (ECOSUR) responded to a report of a manatee calf
that was found alone in Guerrero Lagoon, which is located about 25 km from
Chetumal city. As the calf could not swim very well and an adult manatee that
could be its mother was not found, staff from ECOSUR decided to take care of it
to avoid its death from starvation. It was kept in an inflatable kiddy’s pool
in Chetumal city, where it was examined. The male calf was in good condition. It
was thought to be about 2 weeks old, measured 108 cm and weighed 20 kg. It was
named “Daniel”.
Next day the calf was taken to Dolphin
Discovery, an aquatic park in Puerto Aventuras,
Quintana Roo, where the staff has experience with marine mammals in captivity. He
was assessed and fed by Dr. Roberto Sánchez, and blood
samples were taken. On 16 September the calf was taken back to ECOSUR in
Chetumal, where he has been kept since then in a 3 m circular pool with a
filter system and a boiler to maintain the water clean and warm.
A group of volunteers feed the calf with
milk every 3 hours. Every week Daniel is taken out of the pool to take measurements
and samples for clinical analysis. He is growing well and is beginning to bite
lettuce. At 6 months old in March 2004, his length is 130 cm and he weighs 50
kg.
Local people, groups of children, students
and tourists visit Daniel every day to learn about the manatees which inhabit
Daniel will be in ECOSUR facilities until
April 2004, when the cold north wind season ends. In agreement with local
government, it is intended to keep him in a pen in Guerrero Lagoon about 8
months at least, rearing him in a natural environment and introducing him to
aquatic vegetation. Then, when Daniel is released, he will be tagged with a
radio-transmitter to monitor his movements in his natural habitat. This will be
part of the manatee project research activities of ECOSUR.
People in charge of Daniel are: Benjamín Morales (manatee researcher at ECOSUR), Marco Benítez (vet of African Safari), Rafael Estrada, Daniel Rovelo and
This is the first manatee calf rehabilitation
venture for B. Morales and his group. Save the Manatee Club has been the main
provider of funding. Patty Thompson helped to get us these funds. For further
information or to contribute towards this rehabilitation program, contact
The intensification of large-mesh gill-netting
from 1976, coupled with lack of law enforcement, has been the principal cause
of the decline of dugongs in
Current reports from
Bazaruto’s population of dugong, once estimated at 133 from a
sample of 80 in 1990 (Dutton & Zolho 1990), is
now less than 23 according to air surveys carried out by Dutton and cetacean specialist Dr. Almeida Guissamelo in 2003. Of this population only two had
juveniles. Although it is illegal to
kill dugongs in
Methodology: Since 1990, systematic dugong surveys within the
Bazaruto area have regularly been carried out by various researchers using
different methodologies and search intensities, with aircraft flying at
altitudes varying between 100 m to 150 m along selected transect lines with
sample strip widths varying from 368 to 500 m. Low tide and calm periods were
preferred for counting. The average flight time covering the study area varied
from
Whereas it was possible during the earlier
surveys to derive reasonable estimates using statistical analysis, the current
sparse and unevenly distributed population makes this impractical. For this reason the most recent survey
(March 2003) involved increased search intensity (survey lines 4 km apart and 5-hour
flight) in an attempt to do a total count.
Results: The following graph illustrates the trend in dugong
populations since 1990.