NUMBER 17 APRIL 1992

IN THIS ISSUE: - ENCOURAGING RESULTS FROM FLORIDA MANATEE

CENSUS (p. 5)

- DUGONG RESEARCH IN THE PHILIPPINES AND

THAILAND (pp. 8, 9)

EDITORIAL: THE ENDANGERED RIO SUMMIT

The United Nations Conference on Environment and Development (the so-called Earth Summit) is now only a few weeks away. At this writing it appears that many of the hopes for this unprecedented meeting will be dashed. The great gathering in Rio de Janeiro is in acute danger of degenerating into a media show, largely devoid of substance in the form of binding international treaties to protect the environment. Much of the blame for this belongs to one government - that of the United States of America.

The U.S. is the only nation on Earth that stands in the way of an international global warming treaty, refusing to pledge to reduce or even stabilize its emissions of greenhouse gases. The Bush administration has shown some movement on this issue in recent weeks, but not nearly enough. What is needed is a binding commitment to a 20% reduction of carbon dioxide emissions by the year 2000. The National Resources Defense Council and other energy advocacy groups have estimated that such a policy, far from demanding a major sacrifice on the part of Americans, would actually save the U.S. $2.3 trillion over 40 years.

At a moment when dramatic and visible leadership are called for, not only in the national interest but in the planetary interest, President Bush has only belatedly and reluctantly agreed to attend the Rio summit. This disappointing performance merely leads the long list of environmental issues on which effective American leadership has been sorely lacking - ranging from increased energy efficiency at home, to debt relief and increased aid for the developing world, to an effective response to the root problem of overpopulation.

Unfortunately, leaders do not always appear in the moment of need. As the U.S. approaches a national election, neither political party appears capable of meeting the challenge to think anew and act anew.

Fortunately, in society as in science, revolutions sometimes come not from lone, charismatic leaders but from the ranks of ordinary individuals who come to share a common vision of a better way. These people will be represented at Rio by a wide variety of non-governmental organizations (NGOs), which will be holding their own forum in parallel with the meeting of heads of government - and hopefully pressuring the latter to act responsibly. Many of this newsletter's readers belong to one or more of these NGOs; all of us should be involved in these activities. As scientists and citizens, we must continue to sound the alarm, today and long after the Rio summit, over what is happening to our world. We must seize every opportunity to convince other ordinary people that we may, can, and must take responsibility for, and control of, what our societies are doing.

As sirenologists, we can speak authoritatively about a group of endangered species which are increasingly well-known and popular among the public worldwide, and on which the impacts of human activities can be vividly demonstrated. The message is getting out. Even organizations such as Zero Population Growth are now citing the death toll of Florida manatees as a prime example of human-caused environmental havoc.

The Rio summit may fizzle out in futility; at least it will probably fall short of its goals. This will be the fault of the greedy elites of both North and South, who wish to go on profiting at the expense of the needy majority and of Earth itself. But the resulting, well-deserved reproach to the U.S. government and other obstructors of global sanity will itself bear eloquent witness to how far we have yet to go - as eloquent as any mangled manatee. - DPD

AERIAL SURVEYS FOR SIRENIA: WHERE DO WE GO FROM HERE?

I spent the first five weeks of this year as a guest of the Sirenia Project in Gainesville, Florida. The workshop on the population biology of the Florida manatee in the last week of my stay was the highlight of my very fruitful, interesting and enjoyable visit.

The workshop reviewed most aspects of manatee population ecology through a series of working groups, each of which reviewed a specific topic. I was surprised at the consensus. There was strong agreement that the lack of an accurate population estimate for the Florida manatee is the major obstacle to evaluating its status.

Workshop participants were not optimistic about the suitability of using the data base on scarred animals for estimating absolute abundance. So we will probably have to continue relying on aerial surveys to obtain information on the sizes of sirenian populations.

Most aerial surveys for sirenians still use techniques developed in the 1970's. Animals are usually counted from aircraft flying at fixed heights and parallel to shore. If a large group is detected, a count is made while the aircraft circles. Such surveys assume that sirenians mainly occur close to shore, although in some studies additional transects are flown over areas where suitable habitat is known to extend further offshore. No corrections are made for animals which are not seen by observers.

This technique has proved very useful for identifying major areas of inshore sirenian habitat, especially in developing countries where its ease of implementation is an advantage. However, the method is of limited use in large embayments and areas where the continental shelf is broad, particularly in the case of dugongs which tend to be more coastal than manatees.

The method is also unsuitable for tracking temporal changes in abundance, especially at large spatial scales, because:

a) The number of animals sighted is dependent on their distribution relative to the shoreline, which can be very variable.

b) The sampling fraction is probably variable.

c) The method yields a count without a standard error.

d) The method has no mechanism for compensating for changes in the visibility biases.

The fixed-width survey technique was developed for use at large spatial scales (tens of thousands of square km) and has been used successfully for dugongs in Australia and the Arabian region. The technique incorporates methods for estimating perception bias (animals that are visible but missed) and standardizing for availability bias (animals that are unavailable due to water turbidity). This technique provides a repeatable, standardized minimum population estimate and is useful for producing density distribution maps, for monitoring trends in abundance over large spatial scales and long time periods, and for assessing the likely impact of direct anthropogenic mortality. However, even at large spatial scales, the population estimates produced by the technique have a precision of 12% at best, which means that it would take at least a decade to detect a low-level chronic decline in abundance. The precision of the population estimate is negatively correlated with the population size, which means that it would take even longer to detect changes in smaller populations (or at smaller spatial scales).

Tim Gerrodette of the Southwest Fisheries Center in La Jolla, California, has done simulations which indicate that for populations in the low hundreds of animals, the most likely outcome of any series of surveys will be a non-significant trend even when the population is actually declining.

Thus it will probably be impossible to detect trends in most sirenian populations. Even in areas such as Australia where densities are relatively high, it will not be possible to detect trends in localized areas of impact.

In most areas, a demographic approach will be more productive. We know from population models of other mammals with similar life histories that the crude death rate of stable populations is likely to be between two and ten percent per year. Provided an accurate population estimate is available, this allows us to estimate a sustainable level of mortality for a sirenian population, or at least to put estimates of anthropogenic mortality in perspective. For example, on the basis of his experience in two Aboriginal communities, Andrew Smith estimated that their combined take of dugongs was substantially less than the sustainable yield of the associated dugong population, which I estimated to be on the order of 8,000 animals using a very conservative correction for availability bias. When I repeated the survey five years later, the estimated population estimate had increased slightly (but not significantly). I am optimistic that we were correct in advising the management agencies that the hunting should be allowed to continue.

Where do we go from here? The biggest obstacle to obtaining accurate estimates of sirenian abundance is lack of a method of compensating for the variable proportion of the animals which are invisible to observers due to water turbidity. I have made a first attempt to do this for dugongs, but improvements are needed.

I believe that we should be putting a great deal of effort into obtaining data which will allow us to model the diving and surfacing behavior of dugongs and manatees under a range of conditions. These models could then be used to calculate appropriate corrections for availability bias so that accurate population estimates can be obtained.

Lack of accurate population estimates is a major obstacle to the evaluation of the status of all sirenians, not just Florida manatees. - Helene Marsh

LOCAL NEWS

CARIBBEAN REGION

International Conservation Agreement. - Recently a second Protocol was added to the Convention for the Protection and Development of the Marine Environment in the Wider Caribbean Region: the Protocol Concerning Specially Protected Areas and Wildlife (SPAW). This Protocol was adopted in two stages: its text on 18 January 1990 and the initial versions of its three Annexes on 11 June 1991. The Annexes list protected marine and coastal flora (Annex I), fauna (Annex II), and species to be maintained at a sustainable level (Annex III). The Protocol will enter into force following ratification by nine Contracting Parties.

The Conference of Plenipotentiaries for the adoption of these annexes, which was convened in Kingston, Jamaica, 10-11 June 1991, adopted the draft annexes in their entirety, and showed the region's commitment to a strong Protocol by listing entire groups of species, such as most corals, all mangroves, all sea turtles, and major groups of sea mammals. Listed under Annex II are all species of Cetacea, Sirenia, and Phocidae. Listed under Annex III are all mangroves and a number of species of seagrasses.

The first meeting of the Interim Scientific and Technical Advisory Committee to the Protocol will be held in Kingston, 4-8 May 1992. The agenda will include protection of manatees as well as other threatened species. (Sources: UNEP Caribbean Environment Programme, CEPNEWS 5(3), September 1991; Dr. M. M. Kaufmann, Monitor International)

FLORIDA

Synoptic Manatee Aerial Surveys. - Another statewide aerial survey of Florida's manatee population was conducted on January 17 and 18, 1992. Biologists surveyed coastal and river areas throughout peninsular Florida and four sites in southern Georgia. The survey included known winter habitats but concentrated on warm-water refuges such as natural springs and power plant discharge canals.

Raw counts based on verbal reports from each participating biologist indicate that a record 1,856 manatees were counted, 907 on the East Coast and 949 on the West Coast. These figures are preliminary and may be subject to revision.

These results will be used to update information from two statewide surveys conducted in 1991 (See Sirenews No. 15). Those two surveys counted 1,268 and 1,470 manatees, respectively. Each count provides a minimum count of the population, and is a single event that cannot be used to reliably estimate population size. Surveys over several years are necessary to assess the actual status of the population and determine population trends.

We attribute the higher count this year to better (in fact, nearly perfect) survey conditions such as colder temperatures, improved water clarity, and less wind, rather than a large increase in the population. The count of 1,856 manatees is about as high as the most optimistic researchers would have guessed possible three or four years ago. While it of course does not mean that manatees are no longer endangered, it does give them a little more "breathing room"; the number of mortalities we have been seeing could be better sustained by a population of that size. In any case, this is the first really good news about manatee population biology in some years.

The manatee is still considered endangered because total population size is not the only factor to be considered when determining endangered status. Biologists must also consider other factors affecting the Florida manatee population, such as low reproductive rates, high infant mortality rates, high mortality rates from boat collisions and other causes, water pollution, and loss of habitat. In particular, the record numbers of documented deaths in recent years remain a major impediment to the recovery of the species. More manatees died from human-related causes (68) in 1991 than ever before. Likewise, more small ("perinatal") calves died (53) than ever before. This survey certainly provides no reason to halt any ongoing manatee conservation strategies.

The Department of Natural Resources would like to thank the 27 biologists - representing 14 local, state, and federal agencies, private research groups, and educational institutions - as well as all the other staff who made this survey possible. For example, apart from tasks directly connected with the survey, other staff had to cover two rescue attempts while the local biologists were flying the survey. Ten aircraft were in the air simultaneously on the first day, nine on the second!

The survey was funded largely by the Save the Manatee Trust Fund, which derives its funds from manatee auto license tag sales, boat registration fees, and contributions. Additional funding was provided by the Florida Power and Light Company. - Bruce Ackerman (Florida Dept. of Natural Resources)

Manatee Telemetry Project. - The Florida Department of Natural Resources' Florida Marine Research Institute and the U.S. Fish & Wildlife Service tagged eight manatees at Tampa Electric Company's Big Bend Power Plant in Apollo Beach on December 16 and 17, 1991. Researchers captured and released 15 animals during the two days, but only eight (five females and three males) were found suitable and fitted with satellite transmitter tags. These eight join one male tagged earlier in 1991. Their movements will be monitored for at least three years.

Each transmitter is 21 inches long and is marked by unique colored bands for visual identification. A four-foot tether (designed to break away if entangled) connects the transmitter housing to a rubber harness that encircles the base of the tail. Sensors in each transmitter record water temperature and animal activity. The information is transmitted via satellite to a computer database, and also provides the location of the tagged animals.

A pilot study of four males tagged in Tampa Bay in February 1991 showed that the animals migrated from Tampa Bay as far north as the Suwannee River and as far south as Charlotte Harbor.

In addition to tagging the eight manatees, biologists also obtained measurements of all 15 captured, photographed distinctive scar patterns, and drew blood samples for genetic analysis. The project was funded by the Save the Manatee Trust Fund. - Florida Dept. of Natural Resources

Population Biology Workshop. - A Workshop on Manatee Population Biology was held in Gainesville on February 4-6. A panel of eleven national and international experts on marine mammals, population dynamics and modeling, and wildlife statistics was convened to comment on existing research programs and suggest innovations. Bruce Ackerman and Tom O'Shea served as co-chairmen. (See also the article by Helene Marsh, above.)

Save the Manatee Club Sues for Independence. - In an unusual outbreak of hostility between environmental groups seeking to protect the Florida manatee, the Save the Manatee Club (STMC) has filed suit in Circuit Court to gain corporate independence from its parent organization, the Florida Audubon Society (FAS).

STMC currently has a $640,000 annual budget which is separate from that of FAS, and some 30,000 members compared with FAS's 65,000. In addition, some 60% of FAS's income (exclusive of STMC funds) reportedly comes to them for manatees.

In response to recent efforts by STMC to gain a more independent role for itself, the FAS board of directors voted in late March against allowing STMC to incorporate itself. Judith Delaney Vallee, STMC's executive director, has been fired and FAS has advertised for a replacement. Meanwhile, the locks on STMC's office have been changed and Michael Nelson has been appointed acting director.

According to court papers filed by STMC's attorney, FAS launched "a hostile takeover" against his clients, improperly taking charge of STMC's budget, copyrights, trademarks, and property. The lawsuit also discloses a 1989 memo in which a FAS vice president expressed concern about losing donations to STMC if the organization incorporated. (Based in part on reports in the Orlando Sentinel)

INDONESIA

More Sea Piggery. - At the recent Marine Mammal Conference I had the pleasure of talking with Hans de Iongh about dugong studies in Indonesia, and I took advantage of the opportunity to ask about precise translations of local names for the dugong. He kindly followed up on this and wrote to me as follows: "With respect to your specific question, I traced some information which might interest you through my colleague anthropologist Gerard Persoon, who did his Ph.D. on Siberut. According to him the local people on Siberut call the dugong sakoko ka koat. which literally means 'pig in the sea'. In the Indonesian Dictionary 'Purwadanuda', the seacow is called babi duyung which means 'sea pig'."

There may be a conservation angle to this discussion. It has been suggested that it would be judicious to promote "seapig" and "seacow" as alternatives, according to which local taboos would provide maximum protection! Better yet, as a reporter from the Times of India once suggested, we could promote the idea that dugong "products" were anti-aphrodisiacs! - Paul K. Anderson

IVORY COAST

World Bank Changes Policy on Commercial Logging. - As reported in Sirenews No. 16, the Ivory Coast was discovered to be continuing construction on a major road that threatened coastal ecosystems used by manatees and other wildlife, contrary to an agreement with the African Development Bank (which was funding the project) and a request from the World Bank. The subsequent controversy over this loan, which environmentalists feared would open huge tracts of pristine forest to unsustainable logging, has reportedly led the World Bank to change its former policy and promise to stop funding commercial logging operations in undisturbed tropical forests. No news is available, however, on the present status of the actual road construction. (Source: Environmental Defense Fund, EDF Letter 22(5), November 1991)

THE NETHERLANDS

Manatee Births. - In a letter to Warren Zeiller dated October 29, 1991, Dick Dekker of the Amsterdam zoological park Natura Artis Magistra reports that their male West Indian manatee Joop and female Mary are doing fine, and that the female is pregnant again. The calf born in 1977 was sent to the Antwerp Zoo in 1981, where, unfortunately, he died three years later. Mary's second calf, a female, was stillborn in 1987. Her third calf, a male, was born in 1989 and is now living with other manatees at Burgers Bush at Arnheim.

PHILIPPINES

The Feeding Ecology of Dugongs at Calauit Island, Busuanga, Philippines. - As part of my Master's degree studies, I developed a simultaneous monitoring system which used a team of local observers to count dugongs around Calauit Island from nine shoreline vantage points. Monitoring was implemented each month from March 1989 to May 1990. This allowed me to identify the important dugong habitats around the island. On average, five dugongs were seen per survey day. More dugongs were observed during the months of March and July 1989. These periods coincided with the lull between monsoons that year. The site where dugongs were most often sighted was about 1.5 m deep and supported a seagrass biomass averaging 1060 g/sq. m (wet weight).

The dugongs were shy, making observations difficult. They were observed to graze once per day, usually starting in the late afternoon or at night. Animals usually stayed in front of the spur and groove sections of the reefs. Short seagrasses such as Halodule uninervis, Cymodocea rotundata, C. serrulata, Syringodium isoetifolium, and Thalassia hemprichii showed more evidence of being grazed than the taller species Enhalus acoroides. By direct observations of the area grazed by a single dugong, I estimated that it consumed an average of 68.5 kg (wet weight) of seagrass per day.

I have outlined appropriate conservation measures for dugongs on this island, which is a nature reserve. - Lemnuel Aragones

PUERTO RICO

Protecting the Caribbean Manatee through Education. - The Caribbean Stranding Network and the University of Puerto Rico's Sea Grant College Program have coordinated the printing of 13,000 copies of a full-color manatee poster in Spanish. The poster is based on the theme of "Miss them now, or miss them forever", and its purpose is to let the residents of different Spanish-speaking Caribbean islands learn about how they can help protect this species from extinction.

Save the Manatee Club, the Interamerican University's Biology Department in Puerto Rico, and Joe Pauley sponsored the printing of the poster. It will be distributed free of charge in public and private schools, fishing villages, marinas and natural resources government agencies in Puerto Rico. With the purpose of encouraging other Caribbean organizations to initiate similar education projects, a number of posters have been reserved for distribution in other Caribbean countries.

In a related effort, the Caribbean Stranding Network and the Chelonia Society of Puerto Rico received a small grant from Save the Manatee Club and Puerto Rico's Conservation Foundation to print additional "Caution - Manatee Area" signs in Spanish. The signs are being placed in areas identified as inhabited by manatees and where manatees are in danger of being hit by speeding boats. In addition, Yuisa y Salvador, a natural-size sculpture of a manatee mother and calf, was produced by high-school students and professor Frank Rodriguez at the Commonwealth School in San Juan. The sculpture has visited different schools and activities in Puerto Rico, educating those who were not aware of these sirens' endangered status. - Antonio Mignucci

THAILAND

Dugong Research on the Coast of Thailand. - Dugong dugon, a marine mammal that is very close to being extirpated in Thailand, has long been an interest of Mr. Suwan Saiaueng, a marine scientist working with the Research Section of Thailand's National Park Division. He was the driving force behind establishing a small group of scientists as a dugong research team that is presently studying a dugong population in southern Thailand. The team chose to conduct their research in Had Chao Mai National Park and Koh Libong Non-Hunting Area, where dugong sightings were often reported. These two protected areas are located in Trang Province and both are composed of islands, beaches and extensive seagrass beds in the surrounding waters of the Andaman Sea.

The team decided to carry out three aerial surveys of five days each, to estimate the number of dugongs remaining. Permission from the Ministry of Agriculture and Extension was granted to use their 4-passenger helicopter.

The first survey began on December 7, 1991. Transects were mapped out and a direct count was made covering approximately 72 km. Of the five days flown on the first survey, only three proved to be conducive for observing dugongs; the other two were overcast and rainy. From the first survey, the team estimated that there were about 14 dugongs living in the surrounding area. Of interest was one sighting that appeared to be of a mother with twin calves. Another sighting, of an albino calf, was met with slight skepticism. However, the albino calf sighting was reconfirmed on the second survey.

The second survey occurred in January 1992. Again the team flew for five days, with similar results. This time they were fortunate enough to see the largest herd sighted so far, a group of 20 animals. An albino calf was again sighted, as well as the mother with twin calves. After the second survey the team recalculated the number of dugongs to be approximately 30.

The third survey is scheduled to take place at the end of March 1992, before the monsoon season begins. The actual numberof days on which dugongs will be counted is only two. The other three days will be set aside to allow local village headmen the opportunity to see the dugongs from the air. The team realizes that the dugong's survival depends on the cooperation of fishing villages in the area. Dugongs accidentally caught in fishermen's nets are killed for their meat, oil, and bones, all of which help to enhance the fishermen's very meager income. At present, programs have been initiated to educate and inform villagers on the importance of conserving the endangered dugong. Educational efforts seem to be paying off; after the first aerial survey, on two separate occasions villagers accidentally caught dugongs in their nets and released them instead of killing them. An additional seven days will be spent in the area mapping the seagrass beds, calculating biomass and density, and measuring water temperatures in different areas.

The plight of the dugong in Thailand has been much publicized since the team's first aerial surveys. Legislators, governors, academicians, musicians, actors and actresses, and local villagers have all expressed a desire to help protect the species.

Unfortunately, aerial surveys are quite expensive and impossible to conduct on a regular basis in Thailand. Therefore, the team is now investigating the possibility of establishing a small observation platform on a small mountain in the area. It is still uncertain whether this idea is feasible, since only one dugong has ever been sighted near the mountain. The team is also looking into using radiotelemetry to assist in obtaining vital data on the dugongs. If these animals are to be protected in Thailand, information is vitally needed on their population, distribution, migration, ecology, and habitat requirements. The dugong research team welcomes any advice or suggestions, especially in regard to radiotagging, and surveying small populations. Correspondence should be addressed to either Suwan Saiaueng or Sean O'Sullivan, Attn.: Dugong Project, National Park Division, Royal Forest Department, Jatujak, Bangkok 10900, Thailand; FAX # 579 2791. - Sean O'Sullivan

ABSTRACTS

The following abstracts are of papers and posters presented at the Ninth Biennial Conference on the Biology of Marine Mammals, Chicago, Ill., Dec. 5-9, 1991.

RECENT LITERATURE

Adam, E. 1988. Lamantin: une sirene deguisee en vache. Terre Sauvage No. 21: 60-69.

Beck, C.A., and N.B. Barros. 1991. The impact of debris on the Florida manatee. Marine Pollution Bull. 22(10): 508-510.

Bryant, J.D. 1991. New early Barstovian (middle Miocene) vertebrates from the upper Torreya Formation, eastern Florida panhandle. Jour. Vert. Paleo. 11(4): 472-489. ["Hesperosiren" crataegensis.]

Clark, J.M. 1991. A new early Miocene species of Paleoparadoxia (Mammalia: Desmostylia) from California. Jour. Vert. Paleo. 11(4): 490-508. [P. weltoni, n. sp.]

Domning, D.P. 1991. Why save the manatee? Pp. 167-173 in Reynolds and Odell, 1991, Manatees and dugongs [see below].

Domning, D.P., and V. de Buffre'nil. 1991. Hydrostasis in the Sirenia: quantitative data and functional interpretations. Mar. Mamm. Sci. 7(4): 331-368.

Eldredge, L.G. 1991. Annotated checklist of the marine mammals of Micronesia. Micronesica 24(2): 217-230.

Frey, R. 1991. Zur Ursache des Hoden-Descensus (descensus testiculorum) bei Sa"ugetieren: Die Galoppunfa"higkeit der Testiconda. Teil II. Zool. Jahrb., Abt. Anat. Ontog. Tiere 121(4): 277-330. [Sirenian locomotion.]

Lefebvre, L.W., and H.I. Kochman. 1991. An evaluation of aerial survey replicate count methodology to determine trends in manatee abundance. Wildl. Soc. Bull. 19: 298-309.

Lepthien, E.U. 1991. Manatees. Chicago, Childrens Press: 1-48. [Children's book on Florida manatees.]

Lowenstein, J.M., and G. Scheuenstuhl. 1991. Immunological methods in molecular paleontology. Phil. Trans. Roy. Soc. London, B. Biol. Sci. 333(1268): 375-380. [Proteins from bones of Hydrodamalis gigas.]

Ohnishi, K. 1991. A tentative evolutionary tree of mammalian orders constructed by Hennigian comparison of the amino acid sequences of alpha-crystalin A chain, myoglobin, and hemoglobin alpha chain. Sci. Rept. Niigata Univ., Ser. D (Biol.), No. 28: 19-31.

O'Shea, T.J. 1988. Manatee research efforts under way on Florida's east coast. Endangered Species Tech. Bull. 13(2): 3-4.

Patton, G.W., and E. Gerstein. 1992. Toward understanding mammalian hearing tractability: preliminary underwater acoustical perception thresholds in the West Indian manatee Trichechus manatus. In: D.B. Webster, R.R. Fay, & A.N. Popper (eds.), The evolutionary biology of hearing. New York & Berlin, Springer-Verlag: 783.

Rattner, R. 1990. Manatees among us. Animals, July/Aug. 1990: 26- 31.