SIRENEWS
NUMBER 8
OCTOBER 1987
IN THIS ISSUE:
- ARABIAN GULF DUGONGS
MORE NUMEROUS THAN PREVIOUSLY THOUGHT (p. 9)
- NEW LIGHT SHED ON THE NATURAL HISTORY
OF AFRICAN MANATEES (p. 5)
CAPTURING DUGONGS FOR CAPTIVITY: A COMMENT
In
the April 1987 edition of Sirenews,
there was a report that the
Toba Aquarium in Japan had acquired a
young dugong (named "Serena") to replace the member of
its captive pair that had recently died.
The new dugong was captured in the
Considerable controversy surrounded the
capture of "Serena". There were allegations that other dugongs were killed
in the process, that the dugong population of the area was
too small to sustain the removal of animals, and that the animal was too small
to be reared successfully in captivity.
It was also suggested that the dugong
should have been obtained from
(1) The
institution wishing to capture
the dugong should
be required to
fund an aerial survey to estimate
the dugong population of the proposed capture
area. A local population of at least 100 dugongs should be the
minimum required for a capture permit to be issued for one dugong. Permits should not be granted to remove dugongs from
populations subject to traditional
hunting.
(2) An established benign capture method such
as hoop-netting or bull-dogging
should be used. Hoop-netting, the recommended technique, has now been used successfully
on three occasions in
Marsh, Rathbun,
Smith, Peters, and
Limpus. Dugong capture techniques. [See Recent Literature, below.]
(I can provide copies of this paper. I hope that it will be released
as a
(3) Experience
has shown that the growth
rate of
dugongs in captivity
is much slower than that in the
wild. Animals should
be at least 1.8 m long, preferably more than 2
m long, when captured.
(4) Dugongs
are very sociable and affectionate.
Permits should only be
granted to institutions which plan to keep more than one dugong.
(5) The
permit should be granted only if
the institution has
access to a suitable source of seagrass that has been shown
to be able to sustain the impact of regular harvest.
(6) Institutions wishing to keep dugongs in other than
tropical climates will require the
capacity to heat the water in the holding tank. -
Helene Marsh
LOCAL NEWS
More Dugongs in the
The
estimated dugong population for the areas of the
Radio-tracking Update. - The young male
dugong tagged with a VHF transmitter in
October 1986 was recaptured using a
hoop-net in May 1987 and the transmitter replaced. It has remained close to
where it was caught for almost a year,
using a home range of approximately 9 sq. km. We
plan to capture three dugongs in the
Manatee Awareness Program. - William
L. Hasse, Assistant Director of the Belize Zoo, reports
under date of
"The
Belize Zoo has a manatee
awareness/education program
underway in Belize, and has been giving
slide programs to school groups, distributing posters in coastal and cay areas,
furnishing a ten-minute video on Belize's manatees to interested parties, and
has just held an essay contest in the schools promoting the importance of manatee conservation. In the future, we plan
to include a manatee exhibit at the zoo to help build
additional public awareness regarding manatees in
This
program is supported in part by
funds from
"[Although] we've
never done any type of serious
survey about [manatee] awareness in
"Creole lady - 'Yes, mon,
we need to protect the manatee,
because this part tastes like chicken, this part
tastes like beef, and this part like pork. And if you catch one
manatee, you can feed the whole village, mon!'
"Me - 'I understand that, Miss Doris,
but let me say just one thing
about that. The momma manatee
only has a baby once every
three or four years;
now if you keep hunting them for barbecue, what's going to happen to the
manatee?'
"And she straightened up and
said, 'Yes, mon!! I saw it on TV!! If we keep hunting our
manatees, they'll become distinct!!'
"...
Actually, the story has a happy
ending. She said that she didn't eat manatee
any more, anyway.
Her grandchildren wouldn't let
her."
Manatee
Project Status. - Vera da Silva, widow
of Robin Best, writes
concerning the situation of INPA's manatee project as of July 1987. The Division of Aquatic Mammals is now reduced to only three persons in addition to
assistants, technicians and secretarial
help. Elton Colares, a student of Robin who was doing a thesis on manatee
reproductive physiology, is now working
with otters. He plans to move to Sa~o
Paulo next year for his doctoral work,
accompanied by his wife
Ioni, who has been working on a master's
thesis on manatee
feeding and nutrition.
Vera is continuing her
own work on river dolphins. They
are trying to contract others
to work in
[At
last report, Dr. Iain J.
Gordon of the University of Cambridge, England, was awaiting approval of
his contract to join the manatee project in
Vera
also plans to finish the studies,
begun by Robin, of radio-tagged manatees at the Curua'-Una hydroelectric reservoir, and manatee age determination
using x-rays of flippers and growth rings
in ear bones. Some collaborative projects with
foreign researchers will hopefully also be finished, including ones with Jim Gallivan
on manatee activity and physiology.
She and her colleagues are trying hard to keep the
manatee project going, but at
present the only source of funds for
manatee studies in Amazonia
is the electrical
company ELETRONORTE, which
is primarily interested in using manatees for weed control.
Finally, Vera reports the sad news that
Catue^te^ Albuquerque, who had begun a study of T. manatus on the Brazilian coast, died recently
and has not been replaced.
______________________________________________
DEATH REPORTED
Catue^te^
May 1987, in Brazil (?)
______________________________________________
Exotic
Weevils Introduced for Aquatic Weed
Control. - The Spring 1987 issue
of Aquaphyte, the newsletter of the
Center for Aquatic Plants of
the Institute of
Food and Agricultural Sciences, University
of Florida, Gainesville, reports on
two recent introductions of exotic insects to serve as
biological controls on aquatic macrophytes. The introductions were carried out
by the
On
The
following day, 1200 individuals
of Bagous affinis, a weevil
native to
These
are the first large-scale tests in the
Buddy
Powell was recently hospitalized
for hepatitis and malaria,
but we are relieved to hear that he is now feeling much better and is back at work. With the following news from
Wildlife Conservation International's
(WCI) manatee research project in
These
traps are constructed from a number of wooden stakes stuck
in the bottom and secured together with vine. The
stakes are placed to form a small
semi-circle (2.5 x 1 m) open at one end.
A sliding door of sharpened stakes is placed on
the open end. The
door is held open by a system of smaller sticks which are
balanced together to act as a trigger
mechanism. The trap itself is usually placed in water about
one meter deep. The trap is then baited nightly with fresh cassava peels
thrown randomly inside the trap. When the manatee enters to eat the
cassava, he accidentally pushes
the trigger stick and the door
falls. The manatee is held uninjured in the corral. Normally he
would be killed when found by the
owner of the trap. For research purposes this type of trap has proven very
useful for capturing and radio-tagging manatees unharmed.
The
capture rate using this method can be quite impressive. For
example, using two traps, we caught five manatees in eight days. Unfortunately, illegal use of
these traps still persists in many areas of
We
have had few problems with our
tagging and monitoring program. The VHF radio transmitters developed by
the
We are finding that coastal West African
manatees generally are very
similar in habits to their
Our
tagged manatees have largely
remained in the coastal lagoons; on only a few occasions have they ascended
rivers. They appear to be primarily
solitary, but loose associations with up
to six
other individuals have been noted.
In general, West African
manatees seem extremely secretive
and shy.
They are, probably with good
reason given hunting pressure, quite difficult for a
casual observer to see. Our preliminary tracking
data suggest that they feed and travel primarily at night; during the day they rest quietly in the
middle of a lagoon or river. Three "resting" areas have been
identified where small aggregations (5-10 individuals) of bottom-resting
manatees are often seen. These
resting places are in midstream where there are shallows
less than 2 m deep.
After
this rainy season we will conduct a series of aerial census
and distribution surveys over the coastal lagoons
and major rivers. In cooperation
with the University of Abidjan, we
have begun an extensive project to
identify and map vegetation found along
the coastal lagoons
and rivers. Environmental monitoring of the lagoon
waters is continuing on a routine basis.
Our
training program is progressing
well. We now have an Ivorian
botany student and wildlife officer associated with the project. WCI has invited Mr. Moussa
Kienta of the Malian ministry of water and forests and Mr. Paul Ishaya,
a wildlife biologist from
Between
1 and 14 April 1987, I visited
Nigeria at the invitation of the Nigerian
Conservation Foundation and
the Plateau State Tourism Corporation. The primary objectives were to
survey the status
of West African
manatees (Trichechussenegalensis) in
the Pandam region of the lower
Benue River system (BRS)
and to assess local attempts at
conserving them. Pandam contains
a small lake that has been declared
a manatee reserve by
A
simple survey method was used to assess the status
of manatees in the
Pandam region. This
method has been
used extensively by the
The
survey included primarily the
Pandam region and other associated
rivers to determine the relative importance of
Pandam lake to manatees. A close inspection of Pandam was made by
boatto look for
spoor and evidence of feeding
activity. Aerial surveys were conducted over the Niger River near
its confluence with the
Benue River to look for
manatees and to
obtain an overview of the area and habitat. We could not fly over Pandam because of the limited range of the
aircraft.
Based on the results of this trip, and information reported by Sikes,
it appears that manatees in the
BRS, including the Pandam reserve, are very different in habits from those found
in coastal regions such as Ivory Coast [see report above]. Manatees in the BRS are constrained in their
movements and access to food by low
water during the dry season. As a
result, during the wet season manatees begin to move into lakes, such as
Pandam, via temporary streams.
They will also seek refuge in oxbows or deeper pools of larger rivers. They then spend the dry season in these lakes
and pools which, as the water level drops, become isolated. In Pandam lake I found that there were a number
of aquatic and emergent
plant species which could provide
food for
manatees. Among the few
that I could
tentatively identify were: Ceratophyllum sp., Jussiaea sp.,
Najas sp., Typha sp., Nymphaea sp., and Echinochloa sp.
At
Pandam I saw no
definite sign of manatee
presence. Fishermen say that during the height of the dry season,
because of the decreased
availability of food, manatees do not
feed or defecate. This might explain why
I could find no sign even though the
fishermen assured me that they
were in the lake.
If the fishermen's observations are correct, it is a very
interesting fact and one that
should be investigated more thoroughly.
Robin Best, for example, has reported similar behavior for T. inunguis.
Manatees seem to be found in every
tributary of the BRS that allows access during the rainy season. They were even
reported to reach Yankuri Game Reserve via the
Their overall numbers, however,
appear to be depleted. In
all reports from fishermen it was stated
that manatees were once more
common, but because of hunting
pressure they are now more difficult to find.
I was given three manatee harpoons
and one bottle of manatee oil.
The manatee is hunted for its meat, but it is
actually more valued for its long-lasting oil, which is said to have excellent medicinal
properties.
Pandam
and other lakes like it in the BRS seem to serve as natural
refugia for manatees during the
dry season. It
would appear that Pandam, along with the other lakes,
is extremely important for the
manatees' survival in that region.
The
zoo at Jos has been unable to
maintain manatees alive for longer than
three years. They have lost four or five manatees since the manatee facility was constructed in the
early 1970's. It appears that the water
temperature in the pool cannot be kept
warm enough during periods of
exceptionally cool weather (Jos is located
on a 1500-m
plateau). Health problems,
possibly complicated by cold stress and perhaps inadequate diet, may have resulted in the Jos zoo's poor record with keeping
manatees. It was also reported that some
may have died from skin infections.
The
zoo at Makurdi
presently has one
manatee at its facility. Its
sex is unknown.
This animal, from
cursory observation, seems to be
in fairly good health; that is, it is not
emaciated or suffering from skin lesions. The zoo has
lost two other manatees in the past few years. I was told that it has had up to 10 manatees
at one time.
The director of the zoo at Jos has agreed
to a moratorium on capturing
manatees until the facilities
have been improved and more information is available on the condition
of wild
stocks. The directors at both Jos and Makurdi seem very keen on
promoting manatee conservation. They
are to be complimented
on their attempt to regulate the
taking of manatees from the wild.
I was very pleased to see the degree of
interest in manatees and their conservation in
Dugong
Replenishment Project. - Between
August and October last year, almost
all of the suitable dugong
habitat in the
These
results are remarkably similar to those of Marsh for
These
estimates also demonstrate the need for
dedicated quantitative aerial surveys
to establish the
abundance of sirenians in the marine environment. As a result of qualitative overflights in the
early 1980's, it was believed that the
dugong population of the western Arabian
Gulf prior to the 1983 Nowruz oil spill was only about 50-70 animals. When 38 dugongs died at the time of the oil
spill [see Sirenews Nos. 1, 4, and 5],
grave concern was expressed for the
future of dugongs in the area and
sensational and now apparently
unjustified claims were made in the
international press. Such
reactionary responses, based on minimal
data, are likely to do more harm
than good to sirenian conservation in
the long term.
Using
observer-specific perceptual bias correction factors but
no availability correction
factor (because of
lack of information on surfacing
behavior), the dolphin population in the study
area was estimated to be made up of
3100+_280 Tursiops truncatus, 1300+_200
Sousa chinensis and
1600+_200 unidentified dolphins.
During September 1986 an unknown event or
events resulted in the deaths of at
least 7 dugongs, over 500 dolphins and
tens of thousands of
fish along the Gulf coasts
of Saudi
Arabia and Qatar. Although these
deaths are well documented in extent, their cause has not yet been established and the Regional
Organization for the Protection of the Marine Environment (ROPME)
and the Meteorology and
Environmental Protection Administration
(MEPA) are continuing their investigations.
During
1987 the Dugong Replenishment Project will continue with
surveys of the
Saudi Arabian and North Yemen
Red Sea coastline and parts of
the Arabian Gulf. These later surveys will help
elucidate seasonal patterns in
dugong distribution which will be related to water temperature
and seagrass patterns.
In
June we will attempt to deploy two satellite (PTT)
and VHF transmitters on wild-caught dugongs. This aspect of the work has been made possible through the very
considerable assistance of Galen Rathbun
and Helene Marsh. - Anthony Preen
ABSTRACTS
Lack
of Bile Acids in the West Indian
Manatee (Trichechus manatus latirostris):
First Report of Bile Alcohol Sulfates
as the Dominant Surfactant in
Bile of a Mammal (S.S. Rossi,
L.R. Hagey, C.D. Schteingart,
A.F. Hofmann, S. Kuroki, T.
Hoshita, E.H. Mosbach, and D.K. Odell). - Gallbladder bile from the
West Indian manatee, an herbivorous aquatic mammal of
monophyletic origin dating back to the early Eocene period, was found to lack bile acids,
in contrast to the bile of all mammals.
Instead, manatee bile contained a
mixture of bile alcohol sulfates. The dominant bile alcohol identified by
TLC, mass spectrometry, and NMR
spectroscopy was 5 -cholestane- 3
,6 ,7 -25,26-pentol. The trivial name
-trichechol is proposed
for this previously undescribed compound.
Other C27 bile alcohol sulfates
(pentols and tetrols) present at
lesser amounts were likewise identified
and found to be epimers at C6 and C7 of
-trichechol. The manatee presumably lacks the ability to oxidize the
26-hydroxy group to a carboxylic
acid functionality, and
thus resembles primitive vertebrates such as the coelacanth
and shark. In contrast to the bile alcohols of fishes, however,
the trichechols lack a 12-OH group.
It is not known if trichechols function as
biological surfactants to promote lipid
digestion. NIH grants
DK21506, DK32130,
grant-in-aid from the
Falk Foundation e.V. (
RECENT LITERATURE
Bergey, M., and H. Baier.
1987. Lung mechanical properties in the
West Indian manatee (Trichechus manatus). Respir.
Physiol. 68(1): 63-76.
Burn, D.M., and
D.K. Odell. 1987.
Volatile fatty acid
concentrations in the digestive tract of the West
Indian manatee, Trichechus
manatus. Comp. Biochem. Physiol. 88B(1):
47-49.
Canocchi, D.
1987. On a
skull of a sirenian from the Early
Pliocene of Siena, Tuscany.
Riv. Ital.
Paleont. Strat. 92(4): 497-513.
Colmenero-R., L.C. 1986. Aspectos de la ecologia y comportamiento de
una colonia de manaties (Truchechus [sic] manatus) en el Municipio de Emiliano Zapata, Tabasco. An.
Inst. Biol. Univ. Natl. Auton.
Mexico 56, Ser. Zool. (2): 589-602.
Colmenero-R., L.C., and Ma.
E.H. Zavala. 1986. Distribucion de
los manaties, situacion y su conservacion en Mexico.
An. Inst. Biol.
Univ. Natl. Auton. Mexico 56,
Ser. Zool. (3): 955-1020.
Cornide, R.I. 1984. Anticuerpos
leptospirales en suero sanguineo del
manati (Trichechus manatus L.). Acad. Cienc. Cuba, Misc. Zoologica No. 18 [abstract].
Domning, D.P. 1987. Halianassa
studeri von Meyer,
1838 (Mammalia, Sirenia): proposed designation of a neotype,
and proposed conservation
of Halitherium Kaup,
1838 by designation of a type species. Bull.
Zool. Nomencl. 44(2):
122-125.
Estrada, A.R.,
and L.T. Ferrer. 1987.
Distribution of the West Indian manatee
Trichechus manatus (Mammalia:
Sirenia) in
Furusawa, H. 1984. Discovery of a juvenile sirenian rib
from the Lower Pliocene
in the
Gallivan, G.J.
1987. Robin Christopher Best
1949-1986. Marine Mammal Science 3(3): 292-293. [Obituary.]
MacKay-Sim, A., D. Duvall,
and B.M. Graves. 1985. The West Indian
manatee (Trichechus manatus) lacks a
vomeronasal organ. Brain Behav. Evol. 27(2-4): 186-194.
McKillop, H.I.
1985. Prehistoric exploitation of the manatee in the Maya and circum-Caribbean areas.
World Archeology 16(3): 337-353.
Marsh, H.,
and G.B. Rathbun.
1987. A comparison
of the effectiveness of VHF and satellite telemetry for
studying dugong movements and
habitat usage. In: H. Marsh, Report
to the
Marsh, H.,
G.B. Rathbun, A.J.
Smith, J.G. Peters, and C.J. Limpus.
1987. Dugong capture techniques. In:
H. Marsh, Report to the
Marsh, H., and W.K. Saalfeld.
1987. Aerial censuses of dugongs in
the Central and Capricorn sections of the Great Barrier Reef Marine Park. In: H. Marsh, Report to the
Novacek, M.J., and A.R. Wyss.
1986. Higher-level relationships of
the Recent eutherian
orders: morphological evidence. Cladistics 2(3): 257-287.
Novacek, M.J.,
and A.R. Wyss. 1987.
Selected features of the
desmostylian skeleton and their
phylogenetic implications. Amer. Mus. Novitates No. 2870: 1-8.
O'Keefe, M.T.
1987. Mandate without
muscle. Scubapro Diving & Snorkeling, Winter
1987: 72-75. [Manatee
conservation problems in
Packard, J.M., and O.F. Wetterqvist. 1986. Evaluation
of manatee habitat systems on the northwestern
Rathbun, G.B.,
J.P. Reid, and
Tas'an. 1987. Design
and construction of a
tethered, floating radio-tag assembly
for dugongs. In:
H. Marsh, Report to the
Rathbun,
Reynolds, J.E., III, and J.R.
Wilcox. 1987. People, power plants,
and manatees. Sea Frontiers 33(4): 263-269.
Shaul, W.,
and A. Haynes. 1986. Manatees and
their struggle to survive.
Sokolov, V.E.
(ed.) 1986. Lamantin: morfologicheskie adaptatsii [The manatee: morphological adaptations].
Wang P. and Sun J. 1986.
Distribution of the dugong off the coast
of
Whittow, G.C.
1987. Thermoregulatory adaptations
in marine mammals:
interacting effects of exercise
and body mass. A review. Marine Mammal Science 3(3):
220-241.
Wootton, J.T. 1987. The
effects of body mass, phylogeny, habitat,
and trophic level on mammalian age at first reproduction. Evolution 41(4): 732-749.
Wyss, A.R., M.J.
Novacek, and M.C. McKenna.
1987. Amino acid
sequence versus morphological
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Evol. 4(2): 99-116.
Yalden, D.W.,
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Catalogue of the mammals of
CHANGES OF
ADDRESS
Luz del Carmen Colmenero-Rolon,
C.I.Q.R.O., Apartado Postal 886,
C.P. 77500, Mexico
Lic. Lourdes T. Ferrer, Apartado
Postal 23040 Buenavista, Ciudad de
la Habana, Cuba
Gregor Hodgson, Dept. of Zoology, Edmondson Hall, 2538 The
Mall,
Dr. Sidney Holt,
International League for the
Protection of Cetaceans, Via della Fonte di Fauno 29/6,
00153
Dr. Daniel K. Odell, Sea World of
James A.
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ISSUE:
EDITORIAL: THE ETHICS OF CAPTURING SIRENIANS
Information has
reached Sirenews of a
most regrettable incident
involving the capture of dugongs for public display. It seems
that personnel of a well-known aquarium recently undertook an expedition
for this purpose to a
Good
displays of endangered species in zoos
and aquaria increase public
awareness of and support for species preservation efforts. It is worthwhile to take a few dugongs and
manatees out of the wild
so that they
and their wild
cousins can be appreciated, and in the long run protected, by the millions of people who will inevitably determine their
fate. But this cannot excuse incompetent handling and excessive mortality
of animals, or guilty attempts to hide
the evidence. Such blunders only give
ammunition to those
who would shut down all
captive animal facilities, beginning
with the commercial ones. Many
aquaria around the world (including
the one involved in this incident) have shown that they can do a
conscientious job of keeping marine mammals.
For their own survival as well as
that of the animals, they must not relax their standards.
These standards should include, among
others: proper training
and supervision of personnel in capture and handling
techniques; openness to public scrutiny
of all matters relating to animal care;
and a policy of taking
animals only from populations
known to be sufficiently numerous, even if permits are more easily obtainable
elsewhere - and even if such a policy rules out the taking altogether. To do otherwise will be increasingly
condemned as unethical by both the scientific community and the public. - DPD
EDITORIAL: _____
From
January through August 1987, 27