NUMBER 14
OCTOBER 1990
IN THIS ISSUE:
- NEW DUGONG PROJECT IN INDONESIA
(p. 10)
- PROGRESS IN MANATEE AGE
DETERMINATION (p. 15)
UNITED NATIONS
CONFERENCE ON ENVIRONMENT AND DEVELOPMENT
RIO DE JANEIRO, BRAZIL, 1992
A United
Nations conference of
potentially great
significance to the environment will be
held in Rio de Janeiro, June 1-12, 1992,
coinciding with World Environment Day on June 5. This intergovernmental
meeting, known as UNCED '92 or ECO '92, is being planned
by an UNCED Preparatory
Committee open to all
member governments of the UN. Maurice Strong of Canada will serve as UNCED's
Secretary-General. The UNCED Secretariat, with a staff of about 40, is located in Geneva with additional small
units in New York and Nairobi.
The
Preparatory Committee has two open-ended working groups, which seek
to arrive in
1992 at "specific agreements
and commitments by Governments
and international organizations for defined
activities on environment
and development, specifying targets and
timetables and providing the basis
for concrete action plans."
Issues to be dealt with
by Working Group
1 include, among others,
conservation of biological diversity; those of Working Group 2 include protection of seas
and coastal areas and their living
resources.
The
Preparatory Committee held its first substantive session in Nairobi in August
1990; three further substantive sessions are scheduled (in Geneva, Mar. 18-Apr.
5 and Aug. 12-30, 1991, and in New York in early 1992). Documents approved at
these sessions can be obtained directly
from UNCED's offices in Geneva or from
the Centre for Our Common Future
(Palais Wilson, 52 rue des Paquis,
CH-1201 Geneva; tel. 022-732-7117, telex 27910 ch, FAX
022-738-5046). The UNCED Secretariat has also set up a series of
read-only electronic "conferences" or
databases where the
most important documents in
preparation for UNCED will be posted for
reading and downloading.
These are called
EN.UNCED.UPDATES, EN.UNCED.GENERAL, and some related ones not yet on
line. They are accessible through any
of the Association
for Progressive
Communications electronic networks (Alternex,
Econet/Peacenet, The Web, GreenNet, Nicarao, FredsNaetet, Pegasus).
National
preparatory processes, resulting in the development of national
reports, are also to occur in all
countries under guidelines adopted by
the Preparatory Committee. There is also
a series of regional meetings: regional conferences for
Africa, Europe, and Asia
and the Pacific have already been
held, a further Asia-Pacific meeting is planned for
February 1991, and meetings for Latin America and the
Caribbean and for Western Asia are also planned for early 1991. A fund has been established by the
UN to help the least developed countries participate in the preparatory process.
A significant feature of the UNCED planning
process is the provision for
participation by "Independent Sectors." These include non-governmental organizations
(NGOs) having consultative status
with the UN,
all environment and
development NGOs, business and
industry, trade unions, professional associations, scientific and
academic institutions, women's
organizations, youth groups, religious and spiritual groups, indigenous
peoples' organizations, and other citizens' groups.
A parallel
meeting of the "Independent Sectors" will be held in Rio at the same time as the main
conference, and a series of other UN-sponsored
events will take place
throughout Brazil during 1992.
These will include an official ceremony for heads of state and government in Manaus. The "Independent Sectors" also plan a wide range of preparatory, participatory, and
follow-up activities.
Independent sector organizations
wishing to become involved in the '92 process can obtain information from the
Centre for Our Common Future, which has
(among many other initiatives) begun to publish
a monthly review of
independent sectors' activities called Network
'92. NGOs and individuals are
already actively organizing in many countries (including Brazil and the
U.S.) in order to have an impact on the UNCED process and
to modify the conference themes proposed by the
UN. For example, the proposed themes are
widely viewed as presenting a fragmented picture of ecological and social issues; as omitting some important issues; and as improperly addressing topics such as
the eradication of poverty
as isolated issues rather than as general principles for guidance of
discussion on all themes.
It is important to realize that action must be
taken in the next few weeks and months if it is to have any effect
on the final outcome
of UNCED. By June 1992 the conclusions of the
process will have long since been
effectively set in concrete. There is a
need to ensure that the national reports
now being formulated address the issues as appropriately as
possible, and this will not be easy to
achieve - especially in the U.S., where
Administration policy remains completely and determinedly out of step
with the views of most other
governments on many crucial environmental issues.
Readers of this newsletter,
especially those in developing
countries, now have a short-lived window
of opportunity to get involved in the
UNCED process and affect its
outcome. People from all nations and all walks of life
need to mobilize on an unprecedented
scale, and send their governments to Brazil
with the weight of global
public expectation on
their shoulders. Only this
will make the difference between
holding just another indecisive,
time-wasting intergovernmental
ritual, or moving the world measurably toward a sustainable future. -
DPD
NEW
ADDRESS, PHONE, AND FAX NUMBERS
Please note the new addresses and numbers listed at
the end of this issue
- especially those for the
manatee project in Manaus, Brazil, and for Sirenews.
Also note
that, although most issues of Sirenews
are mailed in franked envelopes
generously provided by the U.S. Fish
and Wildlife Service lab in Gainesville,
Florida, they are produced in and
mailed from Washington, D.C. All Sirenews correspondence should
therefore be directed to Washington and not Gainesville.
RESEARCH FUNDS AVAILABLE
The Foundation
for Field Research is
looking for marine mammal
field projects to support. Grants
to researchers range from
US$1,000 to $25,000, and are derived from
share-of-cost contributions
by volunteer participants on the
research teams. Contact them at P.O. Box 2010,
Alpine, Calif. 92001-0020 USA; telephone 619-445-9264.
LETTER
To Sirenews:
The editor
of Sirenews has recently proposed
the slogan, "Never underestimate a sirenian". I suggest something else,
a reminder which could
be tucked away for ready retrieval.
My slogan is, "Never
overestimate an artist." I'm
stimulated to propose this
bit of grafitti
as a result
of too-frequent encounters with
misrepresentations (or worse)
of sirenian morphology. To
date I know of only one artist,
a delightful Britisher named
Hubert Pepper, who has
produced a reasonably accurate dugong representation.
The latest
in the many offenses
that lie behind
this complaint appears in The Pilot (the Newsletter of the UNEP MArine Mammal
Action Plan) [No. 4, 1989,
p. 13]. A reproduction of a
Vanuatu postage stamp purports to
represent a dugong mother and calf. Mother
dugong's muzzle and mouth
are truly remarkable, strongly reminiscent of those of
a St. Bernard dog. The partial view of
junior's pectoral is quite manatee-like.
The latter brings to mind two occasions when I have picked
up coffee-table books of
Australian mammals in which
the impressive "dugong" closeup showed an
unmistakable West Indian manatee.
Perhaps I'm oversensitive, having to routinely explain to laymen
(and even fellow mammalogists) that dugongs and manatees are,
taxonomically, as different as
dogs and cats, or sheep and goats.
That brings
up another pet peeve which is
relevant here. Steller described
the pectorals of Hydrodamalis gigas
as terminating in hoof-like, bristle-covered pads with which
the animals maintained position
on surf-washed rocks while cropping
kelp. I've yet to see an illustration portraying this feature (as opposed to
manatee or dugong-like
flippers). Rise up, sirenologists! Let's
help them get
things right!
Paul Anderson
[EDITOR'S
COMMENT: A reconstruction of Hydrodamalis,
done by artist Dugald
Stermer under my direction,
appeared in Oceans 13(5): 10-11, 1980. It attempted
to show the flipper correctly. A new
poster by Pieter Folkens, also with my
advice, seeks to improve the depiction further. However,
we'll probably never know if we've got it exactly right.]
LOCAL NEWS
AUSTRALIA
Changes to Fishing Regulations in Southern
Queensland. - Ever since the
introduction of monofilament nylon nets, there has been concern all over the world about the impact
of gill nets on marine mammals,
including dugongs. The only
region in Australia where management
measures have been specifically
introduced to minimize this
problem is the Great Barrier Reef Marine
Park, where some important dugong areas have been closed to commercial fishing. This
response is understandably
very unpopular with fishermen.
In the
last few years,
there have been several
well-publicized incidents of animals drowning in commercial gill nets set
in Hervey Bay in southeast Queensland. This is
the most important area for
dugongs in Queensland south of Cape York,
and the area where fisheries and dugongs are most likely to overlap. Most of the incidents have occurred
in the winter, when seasonal
concentrations of dugongs apparently
occurred in the same areas as similar
concentrations of commercial fish, particularly school mackerel. The numbers of dugongs drowned in some such incidents are
high. For example,
the local Fisheries
Patrol Officer informed me that
at least seven and up to 14 dugongs drowned in a net in August 1986. The toll from this incident is greater than
the number of
dugongs caught by
many remote Aboriginal communities in a year.
The impact
of commercial gill netting on dugong stocks in southern
Queensland is unknown.
However, this mortality is of concern
to urban Aborigines and
Islanders, who understandably resent their hunting being restricted when little
has been done about the problem of incidental capture of dugongs
in gill nets. This mortality is also used by recreational fishermen
opposed to commercial gill netting in an
effort to close this fishery.
The commercial gill net fishermen who regularly
operate in southwestern Hervey Bay have
reacted to this public opposition by using their local knowledge to develop
strategies to minimize the chances of dugongs tangling in their nets. These strategies have been supported by the Queensland Fish Management
Authority, who have changed the
regulations governing the fishery in key
dugong areas in Hervey Bay: (1)
the specifications of offshore set gill or
drift nets have
been changed to increase the chances
of dugongs escaping from the nets if incidentally captured; (2) each
master fisherman can set only one net and must remain at that net at all times to increase the chances of
dugongs being released alive after
accidental capture; (3) netting has been
banned between 4pm and 4am in the months of July, August, and September to reduce the chances
of incidental capture.
If successful,
this approach may be a model for some other areas, especially
those from which it is
impracticable to ban commercial
fishing. - Helene Marsh
Dugong
Pelvic Bones are Sexually Dimorphic. - During a visit to Townsville this past summer, I had the opportunity to study the
large collection of dugong skeletal material that has
been assembled by the James Cook University dugong project and that is
now kept
at the Townsville branch of the Queensland Museum. Thanks to the voluminous and detailed data
associated with this unparalleled collection,
it was possible to demonstrate for the first time that dugong pelvic bones do vary
systematically with sex and,
to some degree, age. I
studied pelvic bones of 70 dugongs (41 males, 29 females), most of
which had previously been aged by Marsh and her coworkers using growth layers
in tusks. I constructed
a dichotomous key that was 93% accurate in placing a given specimen in a category consistent with what
was known of its sex, age, and sexual maturity.
This information
should prove useful to those
needing to extract data on sex and sexual maturity from dugong
carcasses, especially when condition of the carcass precludes use
of more direct indicators.
It may also prove useful, by
analogy, in sexing skeletons
of extinct dugongids. A paper reporting
the results of this
study has been submitted for publication
in Marine Mammal Science. Data will be welcome on whether
pelvic variation in other parts of the range of Dugong dugon conforms
to the pattern here documented for Queensland.
- DPD
Dugongs Do Not Use Their Tusks For Feeding. - Also in
the course of my visit to
Townsville, I was able to examine
stomach content samples from
many of the dugongs in the
James Cook University collection,
as well as ones collected by
Brydget Hudson and her coworkers in Papua New Guinea. As far as I
could determine, there was no difference between males and females
in the amounts of seagrass rhizomes ingested (as opposed to leaves), nor did
adult males appear to have eaten larger
rhizomes than females. This
suggests that the erupted tusks of males are not used
in feeding (specifically, to
harvest rhizomes more effectively than can females), and hence that previous workers have
been correct in assuming that the sexually dimorphic tusks of dugongs are used only in social
interactions.
There
is, however, no evidence that extinct dugongids were
similarly dimorphic, and I
am in the process of testing
the hypothesis that many of these
forms did use their tusks to feed on seagrass rhizomes [see abstract in this
issue]. As one such test,
I used plastic casts of four different kinds of
fossil dugongid tusks, plus an
actual Dugong
tusk, as digging tools to extract rhizomes
by hand from seagrass beds at two
sites in northern
Queensland. With the help of Helene
Marsh's statistical wizardry, I was able
to demonstrate that, whereas size and shape of
tusk are irrelevant
to ability to excavate
rhizomes of Cymodocea and Halodule, longer
and more bladelike tusks are significantly better when the task is excavation of
the larger, tougher, and more deeply buried Thalassia. This
corroborates the hypothesis, and may
help to explain how three, four, five,
or even more species of dugongids were able to coexist sympatrically in
the Caribbean region during the Miocene.
I also conferred with Tony Preen at James
Cook University, and visited Janet
Lanyon at Monash University in Melbourne.
Both have gathered voluminous
and diverse data on dugong
feeding ecology for their nearly-completed doctoral dissertations, and I venture
to predict that we are on the threshold of a significant new synthesis
in our understanding of this topic. I
thank Helene and Janet for their
generous hospitality and help in
making my Australian visit highly
productive as well as enjoyable. - DPD
Dugong "Nose Valves". - In the letter above, I unburdened myself of my frustration with artists' dugong renditions.
Here I'd like to point, more briefly,
to a frequent misconception regarding dugong anatomy (one
of which I suspect I've been guilty in
the past). On the basis of superficial observation
one can easily conclude that on
submergence, dugong nostrils are closed by an anteriorly attached flap, and
this erroneous impression has crept into
the popular literature. The true
situation is quite different. The openings are actually closed by means of
cushion-like pads in the floors
of the nostrils. It appears that in the
relaxed position the floor of the passage is elevated so
that this pad blocks the opening,
and that exhalation and inhalation
require muscular retraction of the floor
to open the air passage (see Domning,
1978, Acta Amazonica 8, Supl. 1, p. 57). It's an eminently sensible
sirenian invention. - Paul Anderson
COLOMBIA
New Amazonian Manatee Project Planned. - Antonio Villa L. reports
that the Colombian natural resources service is planning a program for
the conservation, research, and reproduction of the Amazonian manatee. They are also trying to interest local people
in the
work and educate them about
manatees. Some research facilities and related projects are already in existence
at the Amacayacu National Park. This park, which comprises 3,000 square
kilometers and was gazetted in 1975, is located
in the most southern
territory of Colombia, in close contact with
human populations along the
Amazonas and Putumayo
rivers, where manatees were
abundant in the past.
The project's
planners are looking for help with references, suggestions, and comments.
The contact address is: J. Antonio Villa L., Jefe, Parque Nacional Amacayacu, INDERENA,
Apdo. Aereo 006, Leticia, Colombia.
FLORIDA
Creative Justice
Dept. - A boater caught speeding in a
manatee protection zone
has been sentenced to 32 hours
of shouting warnings to other boaters along the Withlacoochee River.
"It seemed
a common-sense solution to a
problem," Citrus County Judge
Gary Graham said of the sentence
he gave
Al L. Porter on June 19, 1990.
Porter, working his community
service under the Florida Marine Patrol,
will stand on the banks of the
Withlacoochee and holler to speeding
boaters to slow down. The judge
waived a fine and withheld a finding of guilt for Porter, 19,
of Sebastian Inlet on Florida's east coast, but ordered him to carry a personal message to boaters on
the Withlacoochee in west-central Florida.
"If they
have to come back for four or five
weekends and work to
solve the problem they are creating,
it will stick in their
minds," the judge added. "We've
got manatee zones designed to
protect the manatee and they are
just not working.
The manatees continue to be killed." -
Associated Press
The following information is excerpted from a
recent report of the Marine Mammals Section, Florida Department of
Natural Resources.
Manatee Mortality. - As of the end of September,
manatee mortality in Florida in 1990 has soared to 176, already
exceeding the total mortality
for all of last
year by ten
animals. Practically all of the
increase over 1989, however, is due
to last winter's heavy cold-related mortality; mortality from other causes is tracking about
evenly with the 1989 rates. Nonetheless, it's
getting much harder
to be uplifting as we continue
to experience new records in mortality.
Manatee Salvage/Research. - The
emphasis of the salvage program over the last several months
has been to achieve a higher standard
of performance. There have been several
significant positive
changes. We have
capitalized on the
initially inconvenient
circumstance whereby the
Kissimmee Diagnostic Laboratory
abruptly discontinued its involvement in salvage. This necessitated planning
for construction of a
centrally located necropsy facility
using funds from the U.S. Fish
and Wildlife Service (USFWS). A site for this facility is being
secured, and much of
the scientific equipment
for it has
already been purchased. Ground-breaking is expected later this
fall. Also integral to the
operation of a central necropsy facility
is a network of refrigerated trailers to transport carcasses;
these have been designed by Section staff and will be
engineered and manufactured by a
national company.
Research funding
for collaborative projects
on the pathogenesis of clostridial organisms and genetic relationships of captive manatees has been
committed. A request for proposals on manatee acoustic research is in
preparation. Dr. Scott Wright is supervising
the research project
of a student
at the University of
Central Florida concerning the
microanatomy and dynamics of the
manatee thyroid gland. He is
collaborating with Dr. Greg
Bossart (Miami Seaquarium) on the
relationship of circulating levels
of thyroxine and
the immunohistochemical staining
of the thyroid in manatees. Dr. Wright is working with Mote Marine
Laboratory to establish the incidence of
pulmonary anthracosis.
Geographic Information
System. - The GIS
has been extensively used
to create maps that accurately
represent the proposed manatee
protection zone boundaries. Protection zone maps are used along with maps
showing manatee distribution as observed during
aerial surveys and locations of dead animals for display during public
hearings. The maps are also
used by
management staff reviewing water-related projects to determine
potential impacts to manatees.
In September,
new digital base maps were received
which bring GIS coverage
to the entire Florida
shoreline with the exception of Monroe County and Lake
Okeechobee. These two missing pieces
should be received from the National
Ecology Research Center by
late October. The
available base maps have
been provided to other governmental GIS users including the
USFWS, Everglades National
Park, Florida Department of
Environmental Regulation,
and numerous county
governments. Digitized aerial survey
data sets, along with mortality
data through 1989, have also been
distributed to agencies for their use
in protection plans and permit
reviews.
The Marine
Resources GIS (MRGIS), of which the Marine Mammal Section GIS is a part, has purchased a new computer system which
will replace the outdated system purchased in
1982. The SUN fileserver and associated workstations will run at
speeds up to 15 million instructions per second, provide at least 4 billion bytes
of on-line data, and have graphic resolution four times that of microcomputers currently used
by Section personnel. The Section
has purchased a workstation to act as the Marine Mammals node into the
MRGIS via an Ethernet network. By the
end of 1991, each marine mammals researcher and manager should have access to the MRGIS through a menu-driven system on
the network. Until the network is
complete, the Section's GIS personnel will continue to provide both researchers
and managers with data and maps required to publish scientific papers and
effect public presentations.
Population Assessment
and Aerial Surveys.
- Plans are underway for the Synoptic Survey, a statewide aerial survey of manatees
to be conducted twice between
December 15, 1990
and March 15, 1991, after major cold fronts. These surveys must be conducted under
specific weather conditions to
be meaningful. Each survey will require about 25 airplane days
and 50 observer days of effort.
Twice-monthly aerial surveys are
currently being conducted to count manatees and dolphins in Tampa Bay and
Collier County. Another aerial
survey is set to begin in St.
Lucie and Martin counties. Three cooperatively funded manatee aerial
surveys are also ongoing or starting up in Cocoa Beach, Palm Beach
County, and Everglades National Park. An aerial survey of
endangered right whales on their
calving grounds off northeast Florida will be conducted in the coming winter.
Plans are underway for an assessment of visibility
bias in John Reynolds' winter aerial survey of manatees at
power plants in cooperation with the
USFWS and Eckerd College. The objectives
of the research are to estimate the
reliability of power plant aerial
counts and to establish a
population index that can be used
to determine whether the
population is rising or falling. The
percentage of satellite- and radio-tagged animals seen during aerial surveys
will be used to estimate what percent
of all manatees present at the
warm water discharges is observed.
USFWS
satellite telemetry locations have been processed and added to our GIS system, for data obtained between December 1986
and June
1989. These data
are being used as an
additional indicator of manatee distribution for the development of manatee protection zones
and to better predict what weather
conditions will optimize aerial counts at power plants.
Passive Integrated
Transponder (PIT) Tags. - A
research project to investigate the potential to permanently mark
manatees using PIT tags has recently been initiated. PIT tags are
minute glass-encased microchips which have no power source of their own.
An external power
source called a scanner
"reads" the tag's unique
12-digit identification code when passed close to the
injection site. Tags will be injected
under the dermis, at two sites
on each animal. The first phase of the project is being conducted on fresh manatee carcasses to determine the
best site and the best method of injection. Work on this phase began
in late August. The second phase
will be directed toward animals in captivity,
with two animals being tagged
initially at Homosassa Springs Nature World,
Sea World, and Epcot. Epcot Living
Seas contributed $6,000 toward this research. Ultimately, this project
should facilitate obtaining an accurate
population estimate once it is applied to the wild population over several
years.
Telemetry. - A three-year west coast telemetry project
will be begun in February 1991 by
tagging up to five manatees at the warm water
discharges of power
plants in Tampa
Bay with assistance from the
USFWS Sirenia Project. Up to 90 manatees have been counted at the Bay's thermal refuges in
winter, but aerial survey counts
indicate that more than half leave
in the non-winter
seasons. While aerial surveys
have been used to map the
distribution of animals throughout the
Bay, the telemetry study should provide
additional data on daily movements,
migratory pathways, and reactions of tagged animals to boating
traffic. Staff for the
telemetry project will be working
with Sirenia Project personnel this fall to assemble
transmitters and build belts
necessary for tag attachment.
Telemetry project staff and staff members from Tequesta and Jacksonville
will also assist in tracking manatees
tagged on the east
coast by the
Sirenia Project.
Manatee Protection
Zones. - Manatee
protection zones in Collier
and Brevard counties
were adopted in
June by the Governor and Cabinet. Public hearings have been conducted on the
zones in
Palm Beach and Martin counties;
these zones will be presented for adoption at the November 15
meeting of the Governor and Cabinet. The
next rules to be drafted will contain the zones for Dade, Broward, and Duval
counties.
Protection in
the vicinity of the Ft. Pierce power plant has recently been
increased to year-round
status. Sign posting projects are
planned or in progress in the Banana River and in Brevard,
Palm Beach, and Martin counties. The Florida
Inland Navigation District (FIND) was directed by the Legislature
to take over from
the Department of Natural Resources
the sign-posting activities for
the 13 key manatee counties. FIND's fiscal year started on October 1, with $700,000 budgeted for the sign-posting projects.
INDONESIA
New Dugong
Project in the Moluccas. - In
April 1990 a project
was initiated on dugong
management and conservation in the
Maluku Province, Indonesia. The project
is a cooperative one between the Environmental
Study Centre of
the Pattimura University (UNPATTI) at Ambon and the Foundation Aid
Environment at Amsterdam; it is financed by the Commission of the European Economic Community. Participating Dutch
research institutions are the Centre for Environmental Studies of the Leiden
University and the Research Institute for Nature Management at Texel.
The major
objectives of the program
are to
implement a research and monitoring program on dugong populations
and their habitat in selected project areas in the Maluku
Province and to train UNPATTI staff in
research methodology.
Since virtually no research on dugongs has been
carried out in Indonesia, and very little information is available
for the Maluku Province, the project had
to start with a very meager data base.
Initially the eastern part of the
Aru Archipelago had been selected as the
major area for field studies. Nishiwaki and Marsh referred in 1985 to the Aru
Islands as an area where "toward
the end of 1979 dugongs were
apparently still very
numerous". This
information was based on reports provided by Salm in 1984
and Compost in 1980, based in turn on a field survey during 1979.
However, since the visit by Compost in 1979 no more
studies were reported from Aru. This lack of information is partly due to
the remoteness of
the Aru Archipelago
and the logistical constraints on the
implementation of major studies in
such an area.
Compost, who
spent two months on Aru, made
mention of a serious
threat to dugong populations from the increasing use of shark
nets in shallow coastal areas. Based on interviews with local informants, he estimated an annual catch of approximately 1,000 animals in the main
fishing zones.
A project
team visited eastern Aru during April
1990 and selected a suitable site
for further research on the eastern side of
Kobroor Island, near
the village of
Balatan. Based on interviews
with local fishermen in seven villages and
actual observations of dugong catches,
the estimated catch for eastern
Kobroor, in 1989, amounted to 20-40 dugongs. Compost estimated in 1979 an
annual catch of 80-200 dugongs for the fishing zone of East Kobroor (Mairiri and surroundings),
indicating a significant decline in the annual catches in this area.
Although
Compost reported in 1980 that harpooning of dugongs by specialized dugong
hunters was still common in the
area, the team observed in 1990
that this method had been abolished.
Local villagers stated that the major reasons for this were depleted dugong stocks
and the increasing importance of
pearl oyster diving and shark
netting as major sources of income.
Dugongs were
mainly reported as an accidental side catch
in the shark nets.
However, dugong meat
was still a
favored commodity, and dugong tusks and ribs were still traded
for the manufacture of cigarette
holders, as reported by Compost in 1980.
A detailed
analysis of dugong catches in
the village of Balatan
from 1975 onwards revealed that harpooning was a
major cause of dugong
mortality until 1981;
thereafter shark nets contributed almost exclusively to
dugong catches. Incidentally, dugong catches
were reported in tidal traps
(sero) made from wooden fences and placed close to the
mangrove fringe.
Based on this
analysis, it is concluded that
shark netting is the
major cause of dugong mortality in the project area
of eastern Kobroor.
Within the
framework of the project, a plan was
drafted for further studies in the
project area. It was, however,
decided that, due to the
archipelago's remoteness, only part of the
program would be implemented in Aru. Since the project team found feeding tracks of dugongs in several intertidal seagrass
meadows of Halodule uninervis
and Cymodocea rotundata
during an additional field
survey in coastal areas of
Ambon, Saparua, Hairuku, and
Nusa Laut, it was decided to focus part of the
program on the area of Ambon and adjacent islands.
Since April
1990, a field
station in Aru
has been permanently staffed
by scientists and
students of UNPATTI, whereas Dutch
students and scientists of the Leiden
University and the Research
Institute for Nature Management participate
in the research programs in both Ambon and Aru.
A major
theme in the
study is the
seagrass-dugong relationship.
The team investigates in
particular the carrying capacity of
littoral seagrass meadows,
recolonization of feeding tracks,
biomass and growth of rhizomes
and shoots, and dugong distribution. However, since scientific
information on dugongs is very scarce in
Indonesia, the project also covers
dugong catch statistics, dugong aerial
surveys, processing of recovered dugong carcasses, dugong
field observations (an observation tower
was constructed at Aru), dugong
behavior, and habitat mapping. Apart from
biological and ecological
aspects, the program
gives particular attention to the socioeconomic aspects. Project funds have been
allocated to give support for an
improved community water supply
and school facilities in the village of Balatan.
A public
awareness and information
campaign is in preparation, to
inform local villagers about the importance of dugong
conservation. So far in Indonesia,
no particular conservation measures
have been proposed or implemented
with respect to dugong populations. The team concluded in this respect
that the recently established Aru Tenggara
National Marine Park does include
limited areas suitable as
dugong habitat. The project should, therefore, eventually lead to recommendations
on the designation of appropriate
conservation zones. - Hans
de Iongh
School Children
and Dugongs. - In order to
obtain more information about the
dugong, but from another angle, the
pupils in a number
of classes in Koijabi (Aru)
were asked to
make drawings of the
animal, which could
also be used
as an interesting basis for a discussion with them. We expected
that the drawings would give an
indication of the familiarity of the
children with the animal. (On Aru there are no pictures, books or posters
showing the animal.) The teacher, a man
from Kei, though clearly instructed about the aim of the exercise,
wanted his pupils to make a good impression. He presented his image of the animal to the
children first, though it was obvious
that he had never clearly observed the
dugong. He drew one like a fish. Some of
the drawings of the pupils, however, clearly show a good image of the
animal. Interesting in particular were some
drawings showing a kind of "evolution" from the teacher's fish
to the real animal [see illustration below].
All children
had seen dugongs a number of times, even though in Koijabi
some animals might be caught, dragged
ashore and consumed without
being noticed. About 15 children
(out of 48) informed us that their
father had ever caught a dugong, while all of them (except for the boys of the
Chinese shopkeeper) had eaten dugong
meat. Attempts to learn
frequencies of dugong catches or consumption from the children proved to be
very difficult and did not result in very clear answers. -
Gerard Persoon
MADAGASCAR
Madagascar has signed
a treaty with Japan
which opens several sensitive
dugong habitats to the Japanese [fishing] nets. It may spell the end for an already
severely depleted [dugong] stock in
the Antongil and Ile Ste. Marie
areas of eastern Madagascar. -
Pieter Folkens
PUERTO RICO
Stranding Network
Established. - Antonio A.
Mignucci Giannoni reports that a
Red Caribena de Varamientos (Caribbean Stranding Network)
has been created in Puerto Rico to
assess mortality of and to rescue and rehabilitate stranded, sick
or injured manatees, dolphins, whales, and sea turtles. Participants
in the
Network are found so far in
six Caribbean countries (Puerto Rico,
U.S. Virgin Islands,
British Virgin Islands, Dominican Republic, Colombia,
and Venezuela), and more will be
added as the organizers approach other
countries for traineeship and
cooperative agreements. The
Network's address is:
Red Caribena de Varamientos, c/o Departamento de Ciencias Marinas, Universidad de Puerto Rico, RUM,
Apartado 908, Lajas, Puerto Rico 00667-0908.
In order
to attend emergency cases of
sick or injured animals, a
24-hour-a-day phone pager has been established. The number is (809) 782-8686, pager unit
124-3565.
WEST AFRICA
Manatee Surveys.
- Buddy Powell, now based in
Cameroon, reports that he conducted
some brief manatee surveys this past spring
in Guinea-Bissau and Senegal,
where the governments are
hoping to set
up some reserves and management
programs for manatees.
"The
most interesting area", says
Buddy, "was the Bijagos Archipelago, which lies off the coast
of Guinea-Bissau. There are about
50 islands and only 19 are
inhabited. The outermost
is about 40 miles
offshore. It appears that all of
the larger islands have manatees. Orango Island seems to have the largest population. On
Orango there is very little hunting
pressure. However, on Formosa Island, where there also appear to be
quite a few manatees, Senegalese
fishermen build platforms
near freshwater seeps where they
can harpoon the manatees when they come
to drink from the springs. On a 2 km stretch of river
I counted six platforms. It was at the end of the dry season, so only
one seep was still flowing. I tested it with a
salinity meter - sure enough,
very fresh. Manatees seem to feed primarily on Rhizophora, but I also found an extensive meadow of probably Zostera between Formosa and
Carache islands. The fishermen report that manatees are often seen feeding on
the meadow.
"The Bijagos also
has a sizable population of
'marine' hippos. They live in the
mangrove estuaries and can sometimes be seen
in the ocean adjacent to
beaches. We saw only one in the mangroves, but also tracks on the
beach."
Buddy also mentions that manatee meat is still
openly sold in the fish market at
Douala, Cameroon; in fact,
it has become fairly common lately.
At least some
of the manatees
are apparently taken in the
Wouri River adjacent to
Douala. He expects to do some
satellite tracking in Ivory Coast next
spring to follow up on his
earlier research and the current work
being done there by Akoi.
ABSTRACTS
The following abstract is of a paper being
presented at the IV Reunion de Trabajo de Especialistas em Mamiferos
Acuaticos de America del Sur, held in
Valdivia, Chile, Nov. 12-15, 1990. It is here translated from the Portuguese.
Feeding Habits
of the Amazonian
Manatee (Trichechus inunguis)
(I.G. Colares and R.C. Best).
- Trichechus inunguis is the
only sirenian endemic to the
Amazon region and
lives exclusively in fresh water.
It is a non-ruminant herbivore
that feeds on a wide variety of aquatic and
semiaquatic plants. To determine
its feeding habits,
we used an
indirect method: comparison of epidermal tissue of plants found in the digestive tract and/or feces with epidermal
specimens of plants previously
identified in the animal's habitat. Microscope slides were made of specimens from digestive tracts of animals
found dead and/or from feces found floating in different regions of
the Brazilian Amazon, with the objective
of identifying the plants in the diet. We identified 24 species of aquatic
macrophytes in the digestive tracts and
feces analyzed. Among these,
15 species were of emergent plants, 6 of floating plants, and
3 of submerged plants. The greatest number of plants (13 species) belonged to
the family Gramineae; of these,
the animals preferred Paspalum repens and Echinochloa polystachya. The second most frequent family was the
Pontederiaceae, with Eichhornia
crassipes. We observed variation from 1 to 7 plant species in each sample,
with 2 to 3 species per animal being the most common observation. Separating the samples by season
(dry or flood), we found in each season
the same tendency of animals to
have eaten predominantly 2 or 3 species of plants, except
that during the dry
season 23 species
were identified, while only 10 species had been consumed during the flood season.
The following
abstract is of a paper presented at the annual meeting of the
Society of Vertebrate Paleontology,
Lawrence, Kansas, Oct. 13, 1990.
The Rytiodontine Radiation: Diverse Large-tusked Sirenians as Key
Species in Cenozoic
Seagrass Communities (Daryl
P. Domning). - The chief
discovery in sirenian paleontology in
the last five years is that Rytiodus, a rare and "aberrant" dugongid
described in France in 1866, was really the Old World tip of a New
World iceberg. The
Subfamily Rytiodontinae now
stands revealed as a major dugongid clade, probably Caribbean in origin,
that radiated vigorously in the Late
Oligocene and Early Miocene and persisted into the Pliocene. It is so far known to comprise at least five genera, most of which had large, bladelike, self-sharpening tusks.
I hypothesize
that these animals specialized in
excavating large, tough seagrass
rhizomes, thereby disrupting
"climax" seagrass
communities and increasing the latter's
diversity and productivity. This in turn could have helped create and
maintain niche space for other dugongids with smaller tusks and/or body size.
This hypothesis, for
which I have
begun to develop experimental tests, is an attempt to
explain the fact (also newly discovered) that Miocene Caribbean faunas included
at least three and probably five
or more sympatric
dugongid species - a situation unparalleled in the modern
world.
The following
abstracts are of papers presented
at the VIIIth Biennial Conference
on the Biology of Marine Mammals, held in Pacific Grove, California, Dec. 7-12,
1989.
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CHANGES OF ADDRESS
Ioni G.
Colares, Laboratorio de Mamiferos
Aquaticos, INPA, C.P. 478, 69011 Manaus - AM, BRASIL; FAX NUMBER: 092-236-0255
[= Brazilian manatee project
address]
Hans H. de Iongh,
Centre for Environmental
Studies, Leiden University, Garenmarkt 1a, P.O.
Box 9518, 2300 RA Leiden, THE
NETHERLANDS
Daryl P. Domning,
Sirenews, Dept. of Anatomy, Howard University, Washington, D.C.
20059 USA; NEW FAX NUMBER:
202-806-5523; NEW TELEPHONE NUMBER:
202-806-6026.
Tony Preen,
Zoology Dept., James Cook University, Townsville, Qld. 4811, AUSTRALIA
Qiu You-xiang,
Dept. of Zoology, Univ. of
Florida, Gainesville, Fla. 32611 USA
Pat M. Rose,
Florida Dept. of
Natural Resources, 3900
Commonwealth Blvd., Tallahassee, Fla. 32399 USA
Essam Samson, Ingenieur des Eaux, Fore^ts et Chasses,
Ministere du Tourisme, Yaounde,
CAMEROUN
Jeheskel
Shoshani, Elephant Interest
Group, 106 East
Hickory Grove Road,
Bloomfield Hills, Mich. 48304 USA
U. S. Marine Mammal Commission, 1825 Connecticut Ave. NW, Suite
512, Washington, D.C. 20009 USA
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