NUMBER 16                                            OCTOBER 1991

 

 

IN THIS ISSUE:  -  UPDATE ON GULF WAR OIL SPILL (p. 12)

 

                -  COMPUTER ANALYSIS CLARIFIES ANCESTRY OF THE

                   DUGONG (p. 16)

 

                -  MANATEE EXPLOITATION IN BRAZIL: A REPLY (p. 5)

 

 

 

                SIRENIA SPECIALIST GROUP MEMBERS

 

     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      Calgary,   Calgary,   Alberta   T2N   1N4,   CANADA    (FAX:      1/403/2899311)

 

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

 

Dr.  Daryl  P.  Domning,  Dept.  of Anatomy,  Howard  University,      Washington, D.C. 20059, USA  (FAX: 1/202/2657055)


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, PUERTO RICO

 

Dr. Hans de Iongh,  Ecologist,  Centre for Environmental Studies,      Leiden University,  Garenmarkt 1a,  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      University, Clayton, Victoria 3168, AUSTRALIA

 

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, REPUBLIC OF PALAU

 

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

 

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

 

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: 61/9/3061641)

 

Dr. Hector Quintero,  Dept. of Biology, Interamerican University,      San German 00753, PUERTO RICO

 

Dr. Galen B.  Rathbun, U.S. Fish & Wildlife Service, P.O. Box 70,      San Simeon, Cal. 93452, USA  (FAX: 1/805/9273308)

 

Dr. John E.  Reynolds III, Dept. of Biology, Eckerd College, P.O.      Box 12560, St. Petersburg, Fla. 33733, USA

 

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: 1/813/8230166)

 

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., MEXICO

 

 

       SIRENEWS FAX NUMBER:  PLEASE CHANGE YOUR RECORDS!!!

 

     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.

 

 

                 SIRENIA WORKSHOP IN AUGUST 1993

 

     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

 

                    RIVER COWS AND SEA PIGS?

        A PROPOSAL FOR REVISION OF SIRENIAN POPULAR NAMES

 

     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!]

 

 

                           LOCAL NEWS

 

AUSTRALIA

 

     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

 

BRAZIL

 

     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

 

CAMEROON

 

     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 region.

     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

 

     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)

 

INDONESIA

 

     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

 

IVORY COAST

 

     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)

 

JAMAICA

 

     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.

 

MOZAMBIQUE

 

     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)

 

PALAU

 

     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 weather.

     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

 

PERSIAN GULF

 

     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

Arabia

 

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 polluition  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): 165-179.

 

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.

 

 

PERU

 

     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)

 

 

                            ABSTRACTS

 

     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, 1991.]

 

     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 "p1" 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.

 

 

                        RECENT LITERATURE

 

Anonymous.  1991.  Threat  to  manatees.  Marine Pollution  Bull.      22(5):  221.  [Brief  account of conservation activities  by      INPA in Brazil.]

 

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      pelvic  bones of Dugong dugon  (Sirenia).  Mar.  Mamm.  Sci.      7(3): 311-316.

 

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. Biostratigraphy of the Mexican      continental   Miocene:   Part   I,   introduction  and   the      northwestern and central faunas.  Paleontologia Mexicana No.      56: 7-53.  [Reports a new southernmost record of Desmostylus      at La Purisima, Baja California.]

 

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

 

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): 165-179.

 

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.]

 

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 Goeldi

 

Vallee,  J.D.  1991.  Save the Manatee Club.  Florida  Naturalist      64(2): 16.

 

 

                       CHANGES OF ADDRESS

 

Lic. Lourdes T.  Ferrer,  Apartado Postal 627, Zona Postal Habana      13, C.P. 11300, CUBA

 

Larry Hurst,  Desert Sun Science Center, P.O. Box 572, Idyllwild,      Calif. 92349 USA

 

 

 

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