Title: Sirenews
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00099157/00016
 Material Information
Title: Sirenews newsletter of the IUCNSSC Sirenia Specialist Group
Alternate Title: Siren news
Physical Description: v. : ; 29 cm.
Language: English
Creator: International Union for Conservation of Nature and Natural Resources -- Sirenia Specialist Group
International Union for Conservation of Nature and Natural Resources -- Sirenia Specialist Group
Publisher: IUCN/SSC Sirenia Specialist Group
Place of Publication: Washington D.C
Washington D.C
Publication Date: October 1991
Frequency: two no. a year[apr. 1984-]
Subject: Sirenia -- Periodicals   ( lcsh )
Marine mammals -- Periodicals   ( lcsh )
Genre: periodical   ( marcgt )
Bibliography: Includes bibliographical references.
Additional Physical Form: Also issued via the World Wide Web.
Dates or Sequential Designation: No. 1 (Apr. 1984)-
Issuing Body: Supported 1984-Apr. 1992 by the Species Survival Commission of IUCN, the U.S. Fish and Wildlife Service, and the U.S. Marine Mammal Commission; Oct. 1992 by the U.S. Marine Mammal Commission & U.S. Fish and Wildlife Service; Apr. 1993-Oct. 1994 by the U.S. Marine Mammal Commission; <Oct. 1995>- by the U.S. Marine Mammal Commission and Sea World, Inc.
General Note: Title from caption.
General Note: Latest issue consulted: No. 48 (Oct. 2007).
 Record Information
Bibliographic ID: UF00099157
Volume ID: VID00016
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 35841617
lccn - 2009208704
issn - 1017-3439


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DUGONG (p. 16)



The Sirenia Specialist Group has been reorganized; an updated list of the current
members follows. The previous distinction between Executive and Corresponding Members
has been eliminated. Telex and Fax numbers are given where known.

Dr. Paul K. Anderson, Dept. of Biological Sciences, Univ. of
T2N 1N4, CANADA (FAX: 1/403/2899311)

Dr. Eduardo Rafael Asanza Cruz, Dept. de Biologia, Universidad
2184 Quito, ECUADOR

Dr. Daryl P. Domning, Dept. of Anatomy, Howard University,
USA (FAX: 1/202/2657055)

Calgary, Calgary, Alberta

Catolica del Ecuador,

Washington, D.C. 20059,

Dr. William J. Freeland, Principal Wildlife Research Officer, Conservation Commission of
the Northern Territory, P.O. Box 496, Palmerston, N.T. 0831, AUSTRALIA

Dr. Jerry Freeman, Dept. of Biology, Interamerican University,

San German 00753,

Dr. Hans de Iongh, Ecologist, Centre for Environmental Studies, Leiden University,
Garenmarkt la, P.O. Box 9518, 2300 RA Leiden, THE NETHERLANDS (TELEX:
39427 burul; FAX: 31/71/277496)

Dr. Toshio Kasuya, Leader, Small Cetacean Section, Far Seas Fisheries Research
Laboratory, 5-7-1 Orido, Shimizu-shi, Shizuoka-ken 424, JAPAN (TELEX: 03965689
farsea j; FAX: 81/543/359642)


Ms. Janet Lanyon, Dept. of Ecology & Evolutionary Biology, Monash
Victoria 3168, AUSTRALIA

University, Clayton,

Dr. Helene Marsh, Zoology Department, James Cook University, Townsville, Qld. 4811,
AUSTRALIA (TELEX: 7009 aa; FAX: 61/77/796371) (CHAIRPERSON)

Dr. Edgardo Mondolfi, UNEP, P.O. Box 30552, Nairobi, KENYA

Dr. Thomas J. O'Shea, Sirenia Project Leader, U.S. Fish & Wildlife Service, 412 N.E.
16th Ave., Gainesville, Fla. 32601, USA

Dr. Daniel K. Odell, Sea World of Florida, 7007 Sea World Drive, Orlando, Fla. 32821,
USA (FAX: 1/407/3455397)

Mr. Demei Otobed, Chief Conservationist, Palau National Museum, Koror, Palau 96940,

Mr. James A. Powell, Jr., P.O. Box 303, Buea, CAMEROON (FAX: 237/322331 [ask for

Mr. Tony Preen, Zoology Department, James Cook University, Townsville, Qld. 4811,

Dr. R. I. T. Prince, Wildlife Research Centre, Department of Conservation & Land
Management, P.O. Box 51, Wanneroo, W.A. 6065, AUSTRALIA (TELEX: aa94616; FAX:

Dr. Hector Quintero, Dept. of Biology, Interamerican University,

Dr. Galen B. Rathbun, U.S. Fish & Wildlife Service, P.O. Box 70,
USA (FAX: 1/805/9273308)

Dr. John E. Reynolds III, Dept. of Biology, Eckerd College, P.O.
Fla. 33733, USA

San German 00753,

San Simeon, Cal. 93452,

Box 12560, St. Petersburg,

Mr. Patrick M. Rose, Marine Mammal Coordinator, Florida Marine Research Institute, Dept.
of Natural Resources, 100 8th Ave. S.E., St. Petersburg, Fla. 33701, USA (FAX:


Mr. Ismu Sutanto Suwelo, Directorate General of Forests, Centre for Forestry Official
Education & Training, Jalan Gunung Batu, P.O. Box 42, Bogor 16001, INDONESIA

Mr. Tas'an, Gelanggan, Samudra, Jaya Ancol, Jalan Lodan Timur, Jakarta, INDONESIA

Biol. Manuel Vasquez Phillips, Sanchez Ascona 313, Col. del Valle, 03100 Mexico D.F.,


We remind our readers that material faxed to Sirenews should
be directed to Dr. D. Domning, Dept. of Anatomy, at the following number only:
1/202/2657055. Please do not use any of the other numbers formerly given in these pages, as
this may result in charges to your editor for receipt (!) of the material.


The response from sirenian biologists to the prospect of a Sirenia Workshop as part of the
International Theriological Congress to be held in Australia in 1993 has been enthusiastic, and
Barry Fox of the ITC organizing committee has agreed to timetable it. Unfortunately for us,
the venue for the conference has been changed to the University of New South Wales in Sydney
(well south of the nearest dugongs) because the University of Queensland does not have a
900-seat lecture theatre for the plenary sessions.
At the Conservation Biology meeting in Brisbane in September, I participated in an
excursion to look at dugongs and turtles in nearby Moreton Bay (see Tony Preen's report in this
issue). We used the Sea World Boat, and the weather was kind. We had dugongs in clear water
all around the boat. Sea World would be happy to allow their boat to be used for a similar
excursion associated with ITC, and I am trying to organize this. The boat will take 40 and the
cost was A$40 per head including bus fares to the wharf (bring your own lunch, drinks
provided). Helene Marsh


In discussions with both biologists and the public I find myself repeatedly having to
explain that a dugong is not a manatee. My explanation naturally starts with a few details of
anatomy, and progresses to differences in ecology, presumed differences in physiology, and


the still controversial period over which dugongid and trichechid evolutionary lines have been
evolutionarily separated. I point out that formal classification places the dugong and the
manatees in a relationship similar to that existing between canids and felids.
The question I'd like to raise is whether my fellow sirenologists would look favorably
on popular names that better reflect both classification and major niche differences among
living and recently extinct sirenians. My proposal is as follows:
1) Manatees are grazers and browsers. As manatees may be obligated to drink fresh water,
and as the two species which enter salt water may therefore be only secondarily marine,
manatees should be referred to as river cows.
Although T. manatus does enter the marine environment and root out rhizomes, it is the
atypical member of the extant manatees, departing from the riverine "mode" of the other
contemporary trichechids (T. inunguis is exclusively riverine, and T. senegalensis is primarily
riverine in habitat).
2) Hydrodamalis gigas is obviously a seacow, being both marine and a grazer on marine
algae. No name change needed.
3) The dugong should be referred to as the seapig. Like the seacow it is strictly marine, but
many months of watching dugongs feed on a variety of seagrasses, having observed
dugongs deliberately foraging on two species of macroinvertebrates, and reflection on the
unique aspects of dugong anatomy, all incline me toward regarding the dugong as a somewhat
omnivorous rooter into the bottom (at the very least a rhizome specialist). The dugong's
"pigness" is recognized by indigenous peoples who know it well, as indicated by the
Sinhalese and Tamil names "cudalpandi" and "kadalpani", both of which translate literally as
sea pig. I suspect even the Malay word "dugong" is similarly translatable. Paul K. Anderson

[EDITOR'S NOTE: Comments on the above proposal are welcome! As for myself, I think of
Hydrodamalis as more of a browser (= leaf-eater) than a grazer, and of the dugong as more like
terrestrial grazers (= broad-snouted, relatively unselective croppers of "grassy" meadows) as
well as being a rooter (though some extinct dugongids probably did a lot more rooting than
dugongs do today). But what's in a name: could any single name, let alone one borrowed
from some mammalian landlubber, ever do justice to the natural history of a sirenian? If a
dugong is not a manatee, still less is it a cow or a pig. Maybe we should be content to use
"dugong" and "manatee" and let the journalists draw the terrestrial parallels!]



_Indigenous Hunting of Dugongs in Queensland. The current liberalization of community
attitudes to indigenous peoples in Queensland is long overdue, but may have unfortunate


consequences for dugongs. Dugongs are currently protected by the Fisheries Act, from which
people who are resident on Trust Territories (formerly reserves) are exempt. Other people
may apply for permits to take dugongs, but these are rarely granted (once in the last five
years). This has meant no legal hunting throughout most of the populous coastal areas of
Queensland. The Act is now being interpreted differently. Aborigines and Islanders living in
Trust Territories are being told they can hunt anywhere in the State. This means that any
hunting party is legal as long as it is led by an Aborigine or Islander who is officially resident on
a Trust Territory. As Aborigines and Islanders move around a lot, this change has effectively
opened up the whole of the Queensland coast to traditional hunting, a development which I
view as serious, in view of the large-scale movement of Aborigines and Islanders to coastal
areas with limited dugong habitat. Helene Marsh

Home Range and Movements of Dugongs in Subtropical Australia. Thirteen
dugongs in Moreton Bay, southeast Queensland, were tracked using satellite transmitters.
Six were tracked in winter, four in spring and three in summer. Home ranges, based on 95%
of fixes and calculated using the kernel estimator, averaged 64 sq. km and ranged from 28 to
123 sq. km. Because the dugongs were only tracked for an average of 50 days (range 20-88),
these values probably underestimate the dugongs' annual range.
Females maintained larger home ranges than males. There was no difference in the range size
between age classes or season of tracking. The dugongs did not have distinct core areas in their
ranges, but they did have areas of concentrated use. On average, 50% of locations occurred in
15% of the home range area. There was extensive overlap between home ranges, averaging 55%
for full ranges and 25% for "core areas."
Most locations (79%) occurred on seagrass banks. Most of the remainder came from low tide
refuges (channels between banks, or deep water in the Bay). During winter, dugongs undertake
regular migrations between the feeding areas on the seagrass banks in Moreton Bay and a
warm-water refuge in the oceanic waters seaward of the Bay. By travelling 15-25 km from their
feeding areas, the dugongs can move from water temperatures of 16-17 C to temperatures
of 20-21 C. The dugongs synchronize these movements with the tidal currents. None of the
dugongs undertook large movements or left the study area. The maximum rate of travel
recorded was 4.7 km/h (14.3 km in 3 h). The dugongs were more active during the day than at
night. Tony Preen


Manatee Exploitation in Brazil: A Reply. In regard to the report by Monica Borobia
excerpted in Sirenews No. 15, I would like to provide some clarifications that I consider
very important.
First of all, the former government agencies IBDF and SUDEPE today form a single unit,
responsible for enforcement of protective regulations for all flora and fauna in Brazil. This


agency is IBAMA Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais
Renova'veis [Brazilian Institute of the Environment and Renewable Natural Resources] -
which maintains offices throughout the country in an attempt to minimize the impact of
hunting and commercial capture on species in general, by means of laws and regulations that
seek to protect them.
The Amazonian manatee is officially protected by law, as a species in danger of extinction,
since 1967 (Fauna Protection Law, no. 5.197, 3 Jan. 1967; Portaria 3.481, 31 May 1973;
Portaria N-11, 21 Feb. 1986). Nevertheless, it should not be overlooked that illegal hunting
of manatees still occurs in Brazil, and although the number of captures is being reduced with
every passing year, it has not yet reached zero. It is worth emphasizing that this hunting is
neither encouraged in any way nor overlooked by government agencies, since there exists an
agency (IBAMA) charged with enforcing and executing the protective laws and punishing
those who break them.
However, the Amazonian region and its great extent should be taken into consideration.
Many difficulties and unforeseen circumstances can arise in the course of enforcing a
Fauna Protection Law in such a vast and inaccessible region. Each and every capture of
manatees and other protected species is considered illegal, but it is not always possible to
enforce the law, due to the conditions that exist in the region.
Seeking to better protect manatees, officers of IBAMA, during the low-water season,
inspect areas near large lakes where the animals are concentrated for the duration of the dry
season, and where they eventually become very vulnerable to hunters. This inspection is in order
to prevent possible large-scale massacres of the manatees. Whenever lawbreakers are met
with, their equipment is confiscated, fines are imposed, and the data are recorded and
compiled in the Anua'rio Estati'stico of IBGE. This registration of the information does not in
any way represent approval of the hunting on the part of the government agencies, but rather a
recognition of the real situation, without omission of data.
In regard to the published issues of IBGE's Anua'rio Estati'stico which were quoted in
Sirenews No. 15, we are trying to contact the office of IBGE in Brasilia to find out the source
of these figures and to ask that this type of information be identified as pertaining to illegal
captures of animals threatened with extinction, in order to avoid further
misunderstandings in relation to the figures presented.
It is worth emphasizing here once more that we consider correct the attitude of IBGE in
publishing the data on captures of manatees, since if the hunting is taking place, even if it is
illegal, this should be made public. We believe it would be worse for such data to be omitted, in
the attempt to present a false image of what is really happening today in regard to manatee
hunting in this country.
On the other hand, regarding T. manatus, it is worth remembering that the Manatee
Study and Conservation Center of IBAMA is doing very interesting work in preserving the
manatee and raising consciousness among the populations of fishermen on the Brazilian coast.
They are providing talks, educational campaigns, posters, videos, and teaching materials


to the schools, and thereby obtaining very promising results. Planned for 1992 is a similar
project of manatee protection and consciousness-raising in Amazonia, to be developed by us
here at the Aquatic Mammals Laboratory of INPA, in cooperation with the group working with
T. manatus. Ioni Colares [translated from the Portuguese]

Manatees Found in Maranhao, Northeastern Brazil. A recent marine mammal survey
along the Ceara' and Maranhao coasts, northeastern Brazil, revealed the presence and hunting
of West Indian manatees (T. manatus) in areas not previously investigated. On 21 April
1991, I interviewed a former manatee hunter at the locality of Rasgado, Prefecture of
Alcantara, Maranhao. He informed me that he hunted and caught at least eight manatees, as
recently as September 1990, at which time he was advised by officials of the Department of
Environment, Prefecture of Alcantara, that this activity was illegal. Skeletal remains of these
specimens, caught in two distinct areas (Rasgado and Jenipauba) in Alcantara, were
retrieved. These included two mandibles, one partial skull, four ribs and other damaged bones,
reportedly from the last manatees he killed in September 1990.
Since D. P. Domning's collection of an indeterminate rib fragment in 1978, from an
animal killed circa 1975-76 in the lower Mearim River, my findings are the first confirmed
evidence of manatee occurrence in Maranhao. Further investigation should be carried out in the
future to determine whether T. manatus also occurs in other parts of the state and to evaluate
how illegal hunting is affecting the species in the region.
This survey was sponsored by World Wildlife Fund-US through a grant to Salvatore
Siciliano. The Prefecture of Alcantara, through its Department of Environment, provided
logistical support. A paper containing details of the survey is being prepared for Marine
Mammal Science. Salvatore Siciliano


Status and Distribution of Manatees in Cameroon. During June, July, and August of 1989,
a preliminary survey of manatees (T. senegalensis) in Cameroon was conducted under the
supervision of James Powell, with support from the World Wildlife Fund and Wildlife
Conservation International. The objective was to determine the distribution and status of this
species in Cameroon by conducting land and boat surveys of specific watersheds in
conjunction with standard village interviews. The study was intended to complement the
biological research activities of Korup National Park. For this reason, priority was given to
locating manatee populations in the Korup vicinity. After this inventory was complete, other
regions in Cameroon were surveyed to determine the relative importance of Korup manatees to
other manatee populations in the country.
Information on manatee distribution and status was obtained for four regions: (1) Korup
region (Rio del Ray estuary, Ndian and Akpa-Yafe rivers); (2) Mamfe region (Cross, Manyu,
and Munaya rivers); (3) Edea region (Sanaga and Nyong rivers); and (4) Kribi region


(Lokoundje, Kienke, and Lobe rivers). These all lie on the Atlantic coast with the exception of
the Mamfe region.
Manatees inhabit estuarine and riverine habitats in the first three of these four regions.
Manatee occurrence, based on the frequency of reported sightings, appears to be high in
certain areas of Korup, such as the Ndian River and its tributaries. Ndian fishermen see
manatees regularly and can observe up to five manatees a day during the rainy season.
Manatees are seen in the Akpa-Yafe River as far upstream as Korup National Park, where a
waterfall is located. Fishermen in the Akpa-Yafe report seeing at least one manatee a day
during the rainy season. The Akpasang is a small river directly off of the Akpa-Yafe where an
average of two manatees are seen each week during the rainy season. To a lesser extent,
manatees are distributed throughout the Rio del Ray estuary, and are usually seen during the
dry season when the upstream rivers become shallower and less suitable for manatees. Rio del
Ray fishermen see the animal a few times a year; usually no more than one animal is sighted
per observation.
The area of highest manatee density in the Mamfe region is at the confluence of the Cross
and Munaya rivers. They are seen several times a year at this place, and sometimes as many as 3-
5 are spotted during one sighting. Manatees are distributed up the Munaya as far as the village of
Tabo. They are rarely seen in the Manyu or the Awa River (which flows into the Cross River at
the Nigerian-Cameroonian border). Neither the Munaya nor the Manyu is entirely suitable for
manatees because they are shallow and rocky in several areas. In addition, rapids are frequent,
particularly in the Munaya where a series of rapids occurs near Korup National Park.
In the Edea region, the highest concentration of manatees is where the Sanaga River meets the
Atlantic Ocean. Manatees occur in the Sanaga up to the hydroelectric dam in Edea, but are not
observed as frequently in Edea as in areas downstream. They are seen in both the Dihende and
the Dipombe rivers, but rarely in the Nyong. There are also two lakes in this region where
manatees can be found: Lake Ossa (which is connected to the Sanaga River) and Lake
Tissongo. We were unable to visit Lake Tissongo to confirm reports of manatee presence.
The Sanaga River hydroelectric dam, which regulates the amount of water flowing into the
Sanaga River, may have an adverse effect on local manatee populations. A large area of
potential manatee habitat upstream of the dam may no longer be available to manatees since the
dam's construction. More important is its impact on manatees downstream. The dam can
potentially affect manatee habitat by amplifying tidal changes downstream and hence
altering food availability and habitat suitability.
Most of the major rivers in the Kribi region are interrupted by waterfalls and rapids where
bands of harder rock cut across the river bed. While in Kribi, we obtained no positive reports of
manatees inhabiting the Lokoundje, Kienke, or Lobe rivers. The Ntem River, which flows
between Cameroon and Equatorial Guinea, may contain excellent habitat for manatees,
particularly near the Campo Reserve. Unfortunately, we were not able to census this area.
The vegetation varied throughout each region, but most areas contained a diverse array of
overhanging trees and emergent vegetation. Due to poor water quality, submerged aquatic


vegetation was difficult to observe. Natant vegetation was found predominantly in the Edea
Most villages do not use manatee meat, so heavy exploitation is unusual. In Edea, permits are
issued to high-level ministry officials that allow them to take a manatee for a special
occasion. Two manatees were killed for such an occasion in 1987. Nigerian exploitation of
manatees appears to be heavy in the southern Korup region. Due to Korup's proximity to
Nigeria, Nigerians regularly fish in Rio del Ray near Korup National Park.
This three-month study enabled us to assess the possibility of a manatee conservation project
in Cameroon. One promising strategy would be to extend the borders of Korup National Park in
order to safeguard an aquatic sanctuary for manatees. What is needed now is a qualitative
estimate of manatee status, movements, and behavior in Cameroon. In addition, in order to
assess the manatee population trend, monitoring both the manatees and the degree of hunting
pressure is necessary. Melissa M. Grigione


Florida Manatee Mortality Update. The mortality total for the year as of the end of
September has reached 131, which is one more than the total by September of 1990 with the
exception of cold stress deaths (46), and greater than the September 1989 total of 125. Of
the 131 manatees recovered in 1991, 43 were killed by watercraft, 6 by floodgates or canal
locks, 4 by other human-related causes, and 1 by cold stress. Perinatal deaths amounted to
40, other natural causes accounted for 6, and 30 deaths were from undetermined causes.
Finally, an abandoned calf died at Sea World after valiant attempts to save its life over the last
three months.
The total watercraft mortality is up slightly from 40 as of September 1990 and 41 as of
September 1989. Perinatal deaths are also up from 37 (1990) and 32 (1989). Floodgate/canal
lock deaths are up markedly from 1 (1990) and 3 (1989).

Dr. Bruce Ackerman evaluated the mortality data and came up with the following
conclusions. During the decade of the 80's (1980-89), the average annual increase in mortality
was 6.8% per year from all causes and 12.9% due to watercraft impacts. One may infer from
these data that the threat from watercraft is increasing faster than the overall threat to
manatees. (Source: Florida Dept. of Natural Resources)


Fifteen Dugongs Sighted near Ambon, Indonesia. Within the framework of the Dugong
Management and Conservation Project in the Maluku Province of eastern Indonesia, an aerial
survey was carried out covering dugong populations in coastal waters of East Ambon and the
nearby islands of Haruku, Saparua, and Nusalaut. The project is a cooperative one between the


Environmental Study Centre of the Pattimura University (UNPATTI), Ambon, Indonesia; the
Foundation AID Environment; and the State University of Leiden, The Netherlands. It aims
at improved conservation and management of dugong stocks in the province.
No aerial census of dugong populations in coastal waters of Ambon and its surroundings has
so far been reported. The main objective of the survey was to make a first estimate of the
numbers of dugongs surviving in the coastal waters of these densely populated islands.
The flight was carried out on 19 December 1990 with a Piper Aztec lower-decker rented
from the Summer Institute of Linguistics, starting at 9:11 AM during low tide and
comprising one and a half hours of effective survey time. The position of the wings was
clearly a disadvantage for a more quantitative survey, but the view was sufficient to
obtain confirmed observations from more than one observer. Five observers joined the flight,
two UNPATTI staff and three Dutch staff and students. The survey was carried out at 400 m
distance from the shoreline, at a height of 135 m and a speed of 180 km/hr, covering a strip of
200 m on both sides of the plane. There was little cloud cover, low wind velocity, and no
glare. All dugongs were recorded by more than one observer.
A total of 15 dugongs was sighted, of which none was near the east coast of Ambon, 9 were
near the coast of Haruku, 5 near the coast of Saparua, and 1 near Nusalaut. Of these, one was a
cow with a neonate calf. All dugongs observed were within 500 m of the shoreline.
The number of dugongs observed is very encouraging, considering the limited scope of
the survey and the fact that Ambon and surrounding islands belong to the most densely
inhabited part of the province. The project will continue to implement aerial surveys in order
to compile more specific data on dugong population size and distribution. Hans H. de Iongh
and Bob Wenno


Road Threatens Coastal Manatee Habitat in Ivory Coast. A major road is being built
directly through one of the last intact blocks of tropical rainforest in the Ivory Coast, and also
threatens coastal ecosystems, particularly mangrove forests around lagoons, that support
West African manatees. The road, which runs along the Atlantic coast between Sassandra and
Grand Lahou, was being funded by the African Development Bank, which agreed in March
1990, at the request of the World Bank, to delay construction until money to minimize the
habitat destruction could be found. However, an economist employed by the New York-based
Environmental Defense Fund (EDF) subsequently found road building fully underway before
any protection measures had been taken. Sirenews will welcome further information on this
project and the status of manatees in the affected area. (Source: EDF Letter 22(2), April 1991)


Status of Captive Manatees at Alligator Hole River. In June 1991, Antonio A. Mignucci


Giannoni, acting with UNEP funding under the auspices of the Jamaican Natural Resources
Conservation Department (NRCD), led a team to the Alligator Hole River nature reserve in
southern Jamaica, where four Antillean manatees were introduced into a semi-captive
environment in the early 1980's (see Sirenews No. 12). The team's objective was to determine
the status and gender of the impounded manatees.
They were able to account for three of the animals, but did not locate the fourth, which had
not been seen by the reserve wardens in the two previous months. Two of the others appeared
externally healthy, but the third had suffered a deep cut to its peduncle as a result of having once
been tethered to the shore by its tail (as were all the manatees), and was only observed to swim
slowly with its front flippers. All the animals are now allowed to swim at liberty in the river,
but are extremely shy and could not be approached closely or captured by the team. The data
available to the team led them to conclude that at least two, and possibly all three, of these
manatees are female.
The team stated that "no justification exists, not even for education, to hold four, possibly
reproducing female manatees (actually 4 to 8% of the total Jamaican population) apart [from]
the rest of the Jamaican manatee gene pool." They recommended that a thorough
environmental impact statement be drafted to assess the effects of the manatees on the river
system; that a dedicated local biologist be found, hired by NRCD, and trained to monitor the
manatees; that the manatees should meanwhile be left to roam the river undisturbed; and that no
more manatees should be impounded in the river, especially since "it is not clear whether the
river can sustain indefinitely the small manatee population now impounded there."
Sirenews endorses the team's recommendations, and hopes that NRCD will implement them.


Dugong Study Planned in Mozambique. A graduate student and I are beginning a study of
dugongs and dolphins in Mozambique. The work will examine dolphin and dugong
occurrence and distribution in Maputo Bay in relation to increasing gillnet use and
environmental degradation through massive population increase and demographic changes. The
work will encompass four broad facets:
1. Monitor and document the gillnet fisheries of the Bay area, through direct observations
at landing points and markets and interviews with fishermen.
2. Assess the occurrence of marine mammals (dolphins and dugongs) in Maputo Bay
through boat surveys and searching beaches surrounding the bay for carcasses, etc.
3. Document any fisheries interaction, through interviews and observations at markets,
etc., and the examination of carcasses found.
4. Determine which factors, other than fisheries, influence marine mammal distribution and
abundance (an assessment of organic pollution and hydrographic features of the Bay). Vic
Cockcroft (Centre for Dolphin Studies, Port Elizabeth Museum, Humewood, South Africa)



Dugongs in Palau Resurveyed. Dugongs have been exterminated from several
isolated archipelagoes through direct human exploitation. In the Micronesian region, dugongs
now occur only in Palau, and Palauan waters support what is probably the most isolated dugong
population in the world. The closest dugongs are found in Irian Jaya to the south and the
Philippines to the west. In both these areas, dugongs are believed to be under threat from
human exploitation. Thus it is very unlikely that the Palauan population is being supplemented
by recruitment from these areas.
Last August, the Nature Conservancy sponsored a visit to Palau by Galen Rathbun, Tom
O'Shea, Tony Preen, and myself. The objective of our visit was two-fold: (1) to repeat the
aerial surveys for dugongs that had been carried out in 1977, 1978, and 1983; and (2) to
resurvey the area using the more quantitative fixed-width transect techniques that Tony and I
have used in the Arabian region and Australia, respectively.
Unfortunately we managed to complete only the first half of our mission. The transect
survey was terminated by aircraft engine problems (luckily we were in a seaplane) and bad
We saw 26 dugongs, including four calves, on the more qualitative survey. This is
within the range of the numbers counted in the other surveys; however, we consider that,
unless numbers have declined, more dugongs should have been sighted in 1991 than in past
years. We used four very experienced observers. Only three observers, some of whom were
inexperienced, were used in each of the other surveys. On the basis of all the surveys in Palau
and our experience in other areas, we consider that there are likely to be fewer than 200
dugongs in Palau and that their numbers are probably decreasing.
We interviewed knowledgeable residents and dugong hunters with the assistance of
government agencies. The deliberate poaching of dugongs for sport and meat still occurs
regularly even though it is illegal. The hunters regard the penalties as trivial and the likelihood
of their being caught as negligible. The illegality of hunting adds to the thrill!
Although hunting is done primarily for meat, we found jewelry locally crafted from
dugong ribs on sale in four shops. All the retailers knew this was illegal.
Some hunters readily conceded that dugongs are much less common than in the 1960's and
1970's. However, they are reluctant to stop hunting while others continue to do so, despite
social pressure from other Palauans, particularly women. We believe that unless the poaching is
stopped as a matter of urgency, dugongs will become extinct in Palau as they have in
many other archipelagoes. Helene Marsh


Gulf War Oil Spill. In the previous issue of Sirenews, I reported on the Gulf War oil spill,
up to early April 1991. Here I provide an update on the die-off of marine mammals which


occurred during the spill.
On the order of six million barrels of oil flowed into the Arabian (Persian) Gulf during the
spill that commenced in late January 1991. Most of the oil impacted the coast of Saudi
Arabia. It took the oil almost four weeks to reach Abu Ali, a prominent island nearly halfway
down the Saudi coast [see map in previous issue]. This island prevented the further spread of the
main slick. Huge volumes of oil remained buoyant and mobile until May, eventually covering
nearly all of the 460 km of shoreline north of Abu Ali in a blanket of thick oil. In addition to
the main slick, large sheen slicks, made up of a very thin layer of oil and covering thousands of
square kilometers, moved through the open waters of the central Gulf.
At least 93 marine mammals, representing four species, died in the western Gulf during the
spill (see Table 1). Based on my estimates of the time-since-death for 81 carcasses, the die-off
commenced in late February, peaked in late March, and had finished by mid-April.

Table 1. The number of marine mammals known to have died and washed ashore during the
Gulf War oil spill. Data current for period 27 February to 1 May 1991 (for Bahrain, current
to 8 April 1991 only). One dugong in Bahrain was found in a gillnet. One additional dolphin
carcass was seen floating off Khafji.

Country Dugong Tursiops Sousa Neophocaena Unident. Total
dugon truncatus chinensis phocaenoides cetacean

Saudi 11 55 11 0 4 81

Bahrain 3 2 2 1 3 11

Total 14 57 13 1 7 92

Only one dolphin is known to have died along the north coast of Saudi Arabia, where the
impact from the oil pollution was greatest. Dolphins continued to live in this area for at least
the first three months of the spill. All other carcasses were located at least 120 and as far as
250 km south of Abu Ali.
Equal numbers of male and female dugongs and dolphins died. The 11 dugongs for which
body lengths were available comprised mainly adults (7/11) over 2.2 m long and calves (3/11)
less than 1.5 m long. The distribution of body lengths of Tursiops truncatus was normal,
but skewed towards large adults.
Although coincident in time with the oil spill, the die-off was not obviously related to it. No
marine mammals washed ashore along the northern Saudi coastline, where the impact of the oil


was greatest. All but one of the animals were found at least 120 km and as far as 250 km beyond
Abu Ali, where the main oil slick was stopped. In the Gulf of Salwa, where most of the
carcasses washed ashore, a thin layer of oil sheen was the only evidence of the spill. The lack of
carcasses in the northern area was not due to the absence of dolphins. Both Tursiops truncatus
and Sousa chinensis were frequently seen in the area, often within hundreds of meters of oil, or
even surfacing through sheen.
The concentration of carcasses along the southern coast is not likely to be due to an
accumulation of wind-driven carcasses originating in the polluted northern areas. This is
because: (1) dugongs do not normally occur north of Bahrain (Preen, 1989) and so had to have
died locally; (2) very few turtle carapaces (old or recent) were found along the shores of the
Gulf of Salwa, suggesting floating marine vertebrates may not drift far before sinking or being
consumed; and (3) the relative abundance of T. truncatus and S. chinensis carcasses in the
northern and southern parts of the Gulf of Salwa reflected the distribution of these species in
this area (Preen, unpublished data).
Other possible causes of the deaths of these marine mammals include poisoning by a different
pollutant, poisoning by natural toxins, or disease. At present there is no evidence to support
any of these possibilities. Natural poisoning by red tide toxins has been implicated in the death
of hundreds of dolphins along the Atlantic coast of the United States (Geraci, 1989) and the
death of 37 manatees in Florida (O'Shea et al., 1991). The tissue samples collected during this
die-off should be analyzed for clues to the cause of death.
Viewed in isolation, this die-off is not necessarily of great concern. The Gulf War oil spill
was an exceptional event and large numbers of many types of animals died. However, there
have now been a series of marine mammal die-offs in the western Arabian Gulf in recent years.
In 1983, at least 38 dugongs and 33 dolphins died coincident with the Nowruz oil spill (Preen,
1989). In this spill there was no direct evidence to implicate oil in the cause of death. In 1986,
over 500 dolphins and seven dugongs died in Saudi Arabia, Bahrain, and Qatar (Preen,
unpublished data). Again there was no obvious cause of death, although I suspect a red tide.
This series of die-offs (and there are likely to have been more: the 1986 and 1991 die-offs would
not have been detected if I had not been conducting fieldwork in the area) may also be a
manifestation of the poor health of the marine mammal populations of the Gulf, perhaps as
a result of chronic pollution. This possibility should be investigated. Tony Preen

Literature Cited

Geraci, J.R. 1989. Clinical investigation of the 1987-88 mass mortality of bottlenose
dolphins along the U.S. central and south Atlantic coast. Final Report, U.S. Marine
Mammal Commission, Washington, D.C.: 1-63.

O'Shea, T.J., G.B. Rathbun, R.K. Bonde, C.D. Buergelt, and D.K. Odell. 1991. An
epizootic of Florida manatees associated with a dinoflagellate bloom. Mar. Mamm. Sci. 7(2):



Preen, A.R. 1989. The status and conservation of dugongs in the Arabian region. Vol. 1.
MEPA Coastal & Marine Management Series Report No. 10: 1-200.


Peruvian Nature Reserve Threatened by Oil Exploration. A Houston-based American oil
company, Texas Crude, Inc., has (as of May 1991) reportedly negotiated an illegal contract for
petroleum exploration in Peru's Pacaya-Samiria rainforest wildlife reserve, which supports
Amazonian manatees. Nearly 75% of the 2.4-million-acre exploration area lies within the
reserve, which is the only flooded-forest reserve in Peru. Any such exploration in reserves is
forbidden under the Environmental Code enacted in Peru in September 1990. According to
the Peruvian Environmental Law Society, Texas Crude's $24 million contract directly violates
this law and will have a devastating impact on the Pacaya-Samiria reserve, especially if oil spills
occur. Sirenews will welcome information on further developments in this area. (Source:
Rainforest Action Network Action Alert #60, May 1991)


Territoriality, Display, and Mating in Shark Bay Dugongs: A Marine Mammal Lek (Paul K.
Anderson). Between late August and early January, solitary adult dugongs resided in a shallow
cove. Exceptional conditions made possible observation to distances of >500 m from a 10 m
sailing catamaran. Most patrolled exclusive territories. Patrollers had high rates of acoustic
signalling. Despite near absence of food, individuals recognizable by scars held territories for
up to 6 weeks. Patrollers were unusually alert. Approach of another dugong to a boundary
provoked confrontation and display. Intrusion led to combat followed by flight and pursuit.
Patrollers were inferred to be male. Cow-calf herds used rich feeding grounds nearby during late
summer, but the only calf seen in the cove was nearly full-grown and the accompanying cow
was herded and mated by a presumed male. This pair was briefly interrupted by two males
from adjacent territories, but both returned to their territories and the mating continued.
Within its territory a patroller apparently could maintain exclusive access to a female; a pair
followed for 6 hours copulated 10 times. Between copulations the presumed female was
herded against the shallows. All data were consistent with the classic lek pattern. These
observations contrast with "gang-rape" mating described for West Indian manatees in Florida
and for Australian dugongs elsewhere. The cove was occupied in both 1988 and 1989. I
conclude it is a traditional arena site and that patrolling dugongs were participants in a lek. This
is the 6th instance of a classic lek among mammals and the first for a marine mammal. [From


Annual Meeting of the American Society of Mammalogists, Manhattan, Kansas, June 15-19,

The following are abstracts of papers to be presented at the annual meeting of the Society of
Vertebrate Paleontology, San Diego, Cal., Oct. 26, 1991.

Metaxytherium (Mammalia, Sirenia) from California and Baja California (Aranda-Manteca,
F. J., Daryl P. Domning, and Lawrence G. Barnes). New Middle Miocene specimens of the
halitheriine dugongid Metaxytherium (including possibly the best-preserved fossil sirenian
skull yet found) have been discovered at La Mision, Baja California, in the Rosarito Beach
Formation, and in Orange County, California, in the Topanga Formation. Both formations
have yielded rich vertebrate and invertebrate assemblages that aid in correlations and
provide data on paleoecology. Species of Metaxytherium (or "Halianassa") previously
reported from California and Baja California are now referred to other genera and subfamilies
(the hydrodamaline Dusisiren or the dugongine Dioplotherium). Our new discoveries, the only
valid records of Metaxytherium in the eastern North Pacific, demonstrate greater diversity of
sirenians in this region during Middle Miocene time than previously known, as well as a range
extension of the genus. We are presently determining the relationships of these North Pacific
Metaxytherium to those of the eastern South Pacific, the Caribbean-West Atlantic, and
Europe, and to the hydrodamaline dugongids of the North Pacific, which were derived from
some species of Metaxytherium.

A Phylogenetic Analysis of the Sirenia (Daryl P. Domning). Cladistic analysis of 62 cranial
and dental characters in 36 species and subspecies of sirenians, using the Hennig86 computer
program with successive character weighting, yielded 6 maximally parsimonious trees of which
the Nelson consensus tree shown below has a length of 162 steps, a consistency index of 76,
and a retention index of 91. Sample size and intrapopulational variation are pointed out as
insufficiently studied problems in cladistic analysis, and a statistically-based method for scoring
variable characters is introduced.
The tree topology is least certain in three groups of taxa: Eocene dugongids; dugongines
(here including rytiodontines); and species of Metaxytherium. The most novel results of this
study are: (1) The Miosireninae are the sister group of the Trichechidae as previously
defined, and are here placed in that family. (2) The Trichechidae in this broader sense appear to
have arisen somewhat later than previously supposed (late Eocene or early Oligocene rather
than middle Eocene), and are rooted well within the Dugongidae instead of being separately
derived from the Protosirenidae. (3) Dugong is placed within the clade heretofore called the
Rytiodontinae; this is the first strong evidence of where among the Dugongidae the living
dugong's phyletic affinities lie. The subfamilial name Dugonginae is extended to this entire
clade in place of the junior name Rytiodontinae.


Cladogram of the Sirenia

A New Specimen of Behemotops proteus (Mammalia: Desmostylia) from the Oligocene of
Washington (Daryl P. Domning, Clayton E. Ray, and Malcolm C. McKenna). A new
specimen of the primitive desmostylian Behemotops proteus, from Middle or Upper Oligocene
rocks of Washington state, increases knowledge of its dentition and confirms close
relationship to Eocene anthracobunid proboscideans of Asia. This specimen and new
material of Behemotops from Japan indicate synonymy of B. emlongi with B. proteus,
provide knowledge of the upper dentition, and enable reinterpretation of the anterior dentition
of the immature type specimen. We now regard "pl" of the B. proteus holotype as the true
lower canine. M2 and M3 of B. proteus are very similar to M2 and M3 of Anthracobune
pinfoldi. However, we continue to regard Anthracobune as a proboscidean.


Anonymous. 1991. Threat to manatees. Marine Pollution Bull.
account of conservation activities by INPA in Brazil.]

22(5): 221. [Brief

Bradley, John J. 1991. 'Li-Maramaranja': Yanyuwa hunters of marine animals in the Sir
Edward Pellew Group, Northern Territory. Recs. So. Austral. Mus. 25(1): 91-110.

Domning, D.P. 1991. Sexual and ontogenetic variation in the
dugon (Sirenia). Mar. Mamm. Sci. 7(3): 311-316.

pelvic bones of Dugong

Domning, D.P. 1991. A new genus for Halitherium olseni Reinhart, 1976 (Mammalia:
Sirenia). Jour. Vert. Paleo. 11(3): 398. [Crenatosiren, new genus]

Domning, D.P., and V. de Buffre'nil. 1991. Hydrostasis in the Sirenia: quantitative data
and functional interpretations. Mar. Mamm. Sci. 7(4).

Ferrusquia-Villafranca, I. 1990.
Part I, introduction and the
No. 56: 7-53. [Reports a new

Biostratigraphy of the Mexican continental Miocene:
northwestern and central faunas. Paleontologia Mexicana
southernmost record of Desmostvlus at La Purisima, Baia

Hersh, S.L. 1991. Siren census. Sea Frontiers 37(4): 6. [Brief
census in Florida.]

account of statewide manatee


Kamiya, T. 1991. Marine mammals 27. Influence of the Gulf war to dugong. Aquabiology
13(2): 118-119. [In Japanese.]

Kumar, K. 1991. Anthracobune aijiensis nov. sp. (Mammalia: Proboscidea) from the
Subathu Formation, Eocene from NW Himalaya, India. Geobios 24(2): 221-239. [Argues
that the Eocene genus Ishatherium is a sirenian and not a proboscidean.]

Ogasawara, K., and R. Morita. 1987. Molluscan assemblage of the Yanagawa Formation,
Fukushima Prefecture -- co-occurred molluscs with Paleoparadoxia sp. Rept. Tohoku
Branch, Geol. Soc. Japan No. 17: 26-27. [In Japanese.]

Ogasawara, K., and R. Morita. 1990. A new Miocene gastropod species co-occurred with
Paleoparadoxia specimens from the Yanagawa Formation, Fukushima Prefecture, northeast
Honshu, Japan. Saito Ho-on Kai Mus. Nat. Hist., Res. Bull. No. 58: 25-30.

O'Shea, T.J., G.B. Rathbun, R.K. Bonde, C.D. Buergelt, and D.K. Odell. 1991. An
epizootic of Florida manatees associated with a dinoflagellate bloom. Mar. Mamm. Sci. 7(2):

O'Shea, T.J., and C.A. Salisbury. 1991. Belize a last stronghold for manatees in the
Caribbean. Oryx 25(3): 156- 164.

Provancha, J.A., and C.R. Hall. 1991. Observations of associations between seagrass
beds and manatees in east central Florida. Florida Scientist 54(2): 87-98.

Reid, J.P., G.B. Rathbun, and J.R. Wilcox. 1991. Distribution patterns of individually
identifiable West Indian manatees (Trichechus manatus) in Florida. Mar. Mamm. Sci. 7(2):
180- 190.

Reynolds, J.E., III. 1991. Distribution and abundance of the West Indian manatee (Trichechus
manatus) around selected Florida power plants following winter cold fronts: 1990-1991. iii
+ 39 pp. [Report prepared for Florida Power & Light Co., P.O. Box 14000, Juno Beach,
Fla. 33408, order number B89806- 00264.1

Schweigert, F.J., S. Uehlein-Harrell, G.V. Hegel, and H. Wiesner. 1991. Vitamin A (retinol
and retinyl esters), -tocopherol and lipid levels in plasma of captive wild mammals
and birds. Jour. Vet. Med., Ser. A, 38(1): 35-42.

Suzuki, K., et al. 1986a. New skeleton of Paleoparadoxia with stratigraphical and
sedimentary environmental remarks in Yanagawa-town, Date-gun, Fukushima Prefecture,


Japan. Essay in Geology (Prof. N. Kitamura Commemorative Vol.): 453-464. [In
Japanese; Engl. abstract.]

Suzuki, K., et al. 1986b. Investigated report on Paleoparadoxia of the Yanagawa Formation.
Yanagawa (Japan), Yanagawa Town Educational Committee: 1-22. [In Japanese.]

Toledo, P.M. de, and D.P. Domning. 1991. Fossil Sirenia (Mammalia: Dugongidae)
from the Pirabas Formation (Early Miocene), northern Brazil. Bol. Museu Paraense Emi'lio

Vallee J.D. 1991. Save the Manatee Club. Florida Naturalist

64(2): 16.


Lic. Lourdes T. Ferrer. ADartado Postal 627. Zona Postal Habana

Larry Hurst. Desert Sun Science Center. P.O. Box 572. Idvllwild.

13. C.P. 11300. CUBA

Calif. 92349 USA


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