14. Conclusions and Priorities for Otter Conservation
Chris Mason and Sheila Macdonald
All otter species are associated with aquatic habitats. Water, of course, is also an essential resource for man. For millennia the wetland habitat has been modified to provide water for domestic uses, for agricultural irrigation, and for industries. Wetlands have also provided foods, such as fish, and have acted as a cheap and simple way of disposing of the wastes of human civilization. Human settlements have also concentrated in river valleys, alluvial plains, or along coasts, with their important wetland habitats. The biotope of otters has always been under threat from drainage, habitat destruction, overexploitation, and pollution. However, the enormous growth in the human population during this century, together with rapid increases in industrialization, agricultural production, and overexploitation of natural resources, have had major impacts on otter populations.
Before presenting priorities for each species in turn, we first consider, in general terms, factors which need to be taken into account in developing conservation strategies for this remarkable subfamily of animals.
Contamination of food resources with organochlorine pesticides and PCBs has led to large and widespread declines in the numbers and range of the Eurasian otter (Lutra lutra), the only species which has been systematically studied for pollutants. Evidence suggests that they have also had a negative impact on at least some populations of the North American river otter (Lutra canadensis). There have been no studies on other species. The use of organochlorine pesticides has been largely curtailed in the developed world, but they are still exported to and widely used in the developing world. Restrictions have also been placed on the use of PCBs, but they are still manufactured and are widely present in closed systems, such as transformers, and present a problem not only now, but for decades or longer to come. Organochlorine pesticides and PCBs are frequently dispersed over vast distances, thereby causing ecological problems in areas remote from their manufacture or use. We therefore strongly urge that there should be a worldwide ban on the use of persistent organochlorine pesticides. PCBs should be replaced by non-accumulative compounds as a matter of urgency, and proper facilities for the destruction of PCBs by incineration should be further developed and strictly controlled.
As with many species, otters are under threat due to habitat destruction, in some areas on a large scale. Most otter species live naturally at low densities, so that viable populations are unlikely to be maintained in all but a few of the largest protected areas. We need more information on the habitat and resource requirements of all otter species and on the size and configuration of suitable habitats necessary to maintain viable populations. It is essential to link the conservation of otters to the conservation of other wetland species to provide an integrated approach to wetland protection. An inventory on the status of otters in all national parks and Ramsar sites would be useful first steps. Where the modification or destruction of significant wetlands is envisaged, there must be an environmental impact assessment on which rational decisions can be based, and the impact of developments on otters should be an integral part of such assessments. It is essential however, to consider the conservation of otters both in the wider landscape and the small scale, for steady attrition of riparian habitat is, in the long term, as damaging to otters as the loss of major wetlands. We must press for the conservation of riparian habitats and for the restoration of those which have been degraded. The concept of habitat corridors between protected areas is of crucial importance to the survival of otter populations, for it will prevent the fragmentation of populations. The numbers of animals in fragmented units may be too small to ensure long-term survival, while enforced inbreeding will result in the loss of genetic diversity and eventually population viability.
Otters have long been hunted for their pelts which, historically, resulted in major population declines of the North American river otter (Lutra canadensis) and the sea otter (Enhydra lutris), the latter almost to extinction. In recent times, trapping and hunting has had a major impact on South American species, especially the giant otter (Pteronura brasiliensis). At present, international trade in many otter species is prohibited. We are concerned that trade in certain species may allow the illicit exploitation of protected species, for pelts are difficult to tell apart (for instance between the Eurasian, smooth, and hairynosed otters). The only species for which there is a regulated trapping season is the North American river otter. Although the management of this species is generally effective, we are concerned that quotas are in some instances based on rather inadequate independent information on population trends, especially as it is known that otter declines can occur rapidly and go largely unnoticed. The management guidelines that have been developed by the authorities in Canada and the United States need to be implemented strictly, and if any populations become depleted, exploitation of them should cease until full recovery has taken place.
Otters feed extensively on fish and/or shellfish, and therefore come into conflict with fishermen and fish farmers. Because most otter species occur naturally at low density, it is likely that much of the alleged damage is exaggerated. However, it is important to obtain more concrete information on the impact of otters on both natural and farmed fisheries and, where damage is considered significant, to develop effective methods of ameliorating it.
Because otters can only be conserved in the wider environment, it is essential that effective educational programs be developed. Otters are naturally appealing animals, and where their image has been imaginatively promoted (for example the sea otter in the United States and the Eurasian otter in several European countries), the public has developed considerable empathy with the animals. In Britain, for example, some mention of the otter occurs almost every week in the media. It is therefore an important priority to raise the profile of otter conservation in other parts of the world.
Much has been learned recently about keeping and breeding otters in captivity and, provided the welfare of the animals is kept paramount, zoos have a role to play in this promotion of conservation. Studbooks should be maintained for all otter species in captivity, especially as some reintroduction programs are contemplated and more will be in the future. Captive breeding programs are probably needed for some of the rare otter species.
Reintroduction programs should be seen as a last resort in otter conservation and any program should strictly adhere to IUCN guidelines. They are likely to prove extremely expensive. Nevertheless, there are occasions when reintroductions are the only possible option, and in these cases, they should be encouraged.
It is clear that we still have much to learn about the biology of otters. All well-founded scientific studies into the biology of otters should have our strongest support where the results will further our aims of otter conservation. Research is needed to elucidate the effects of the factors listed above, in particular pollution, habitat management, hunting, population fragmentation, and conflicts with fisheries. Research will also be needed on breeding biology and general husbandry for maintenance in captivity, as well as on reintroduction techniques and strategies.
Since this action plan deals with only 13 species, we present here summaries of priorities for each species in turn, based on the information provided in the preceding chapters. We have categorized otter species into three broad groups based on current information as follows:
Species of Global Conservation Concern. This category comprises those species known to be endangered and/or those limited to a restricted geographic range for which there is little or no recent information.
Species of Local Conservation Concern. This category comprises those species which are considered to be threatened locally or regionally following recent declines, but which are not yet globally threatened.
Species Receiving Adequate Conservation. This category comprises two species which, although potentially vulnerable, are confined to regions where conservation measures, and resources for their implementation, should be adequate and readily available.
The distribution of this species is very poorly known, and it is thought to have disappeared from wide areas from where it was formerly recorded. Nothing is known of its ecology. Conservation priorities are as follows:
Field surveys, using standard methods, should be conducted throughout the range of this very rare species to determine current distribution and status. Priority areas for such surveys are those areas where populations are thought to survive in Sumatra, Kalimantan, and Java (Indonesia), and Sabah and Sarawak (Malaysia). Surveys should also be conducted in parts of the former range from which there are no recent records but in which populations might survive: Brunei, Peninsular Malaysia, southern Thailand, Cambodia, and southern Vietnam.
Studies on the ecology and conservation requirements of this very poorly-known species should be initiated in protected areas where it is known to occur. Priority sites for such studies would probably be in Sumatra, Java, or Kalimantan in Indonesia. Such studies should seek to identify those habitat features that must be conserved if this rare species is to survive and recover its numbers.
Improved protected area management is needed for all reserves in which the hairy-nosed otter occurs, and management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. The draining of wetlands in Sumatra and Kalimantan in particular should be considered in this light, and ways should be explored to increase agricultural output to meet human needs, while at the same time retaining the ecosystems in a satisfactory condition for this species. Likewise, the extraction of gravel from river beds in Sumatra also needs careful regulation.
The use of pesticides in agriculture, and the dumping of toxic wastes from factories and domestic wastes and detergents from human settlements needs to be strictly regulated. In particular, the use of certain persistent chemicals, such as organochlorines, should be phased out.
This species requires strict legal protection in Indonesia, where it is thought the bulk of the known populations survive. All trade in the pelts of the hairy-nosed otter should be prohibited by national laws, and there is a need for stricter compliance with the wildlife protection laws in several parts of its range.
There should be initial attempts to keep and breed this species in captivity, with a view to starting a coordinated captive breeding program. In the long-term, the possibility of reintroducing the species in parts of the former range might be considered.
A young Congo clawless otter (Aonyx congica) in captivity (Photo by Elizabeth Joy).
This species is known only from Angola, Cameroon, Central African Republic, Congo, Gabon, Nigeria, Rwanda, Uganda, and Zaire. It might also occur in Burundi. Its ecology and conservation requirements are unknown. Conservation priorities are:
Field surveys, using standard methods, should be conducted in the range of this rare species to determine current distribution and status. Priority areas for such surveys are the large protected areas within the equatorial forest belt in Africa: Dja and Korup in Cameroon; Dzanga-Sangha in Central African Republic; Conkouati and Odzala in Congo; Lope in Gabon; Oban Hills in Nigeria; and Ituri, Kakuzi-Biega, Maiko, and Salonga in Zaire. Surveys in Zaire are of the highest priority, since it is here that the largest areas of habitat are conserved.
Studies on the ecology and conservation requirements of this very poorly-known species should be initiated. Such studies should seek to identify those habitat features that must be conserved if this rare species is to survive.
Improved protected area management is needed for all reserves in which the Congo clawless otter occurs, and management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of timber concessions in the African equatorial forests on a long-term sustainable use basis, rather than clearance. There is also a need to integrate indigenous people and their needs into the conservation and sustainable management of these forests. In local situations, it might be necessary to limit excessive hunting of otters.
In local situations, it might prove necessary to devise means of reducing the numbers of this species being accidentally killed in fish traps.
There should be initial attempts to keep and breed this species in captivity, with a view to starting a coordinated captive breeding program.
This species is one of the most endangered of the Latin American otters, having suffered severely from overhunting for pelts. Conservation priorities are:
Field surveys, using standard methods, should be conducted throughout the range of this rare species to determine current distribution and status, and degree of recovery (if any) in populations following protection and closing of the trade in pelts. Priority areas for such surveys are: the Misiones and Corrientes provinces in Argentina; the Manuripi Faunal Reserve and Amboro National Park in Bolivia; the Pantanal, Rio Negro (Matto Grosso do Sul), the Parana-Iguacu area, and appropriate sites in the Amazon basin in Brazil; El Tuparro and Sierra de la Macarena National Parks, Arauca Sanctuary, and Miritiparena River in Colombia; the Bobonaza, Ishpingo, Cuyabeno, Guapi, Lagarto Cocha, and Tarapuy Rivers in Ecuador; the interior of French Guiana; Morawhanna, Russel Lake, Lama and Maduni Creeks, and Mahaica, Abary, Mashivean, and Morewan Rivers in Guyana; tributaries of the Paraguay and Parana Rivers in Paraguay; Manu National Park and other lowland areas in eastern Brazil; the Corantijn, Nickerie, Wayombo, Coppename, and Commewijne Rivers in Suriname; and the Apure, Caura, Ventuari, Arauca, Cunaviche, Capanaparo, Claro, Aguaro, Cinaruco, and Portuguesa rivers, and the Orinoco Delta in Venezuela.
Studies on the ecology and conservation requirements of this remarkable species should be continued. Such studies should seek to identify those habitat features that must be conserved if this rare species is to survive.
Improved protected area management is needed for all reserves in which the giant otter occurs, and management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of forest and wetland habitats on a long-term sustainable use basis. There is also a need to integrate indigenous people and their needs into the conservation and sustainable management of the habitats of this species. When major development projects are being considered (e.g. dam construction, mining operations), environmental impact assessments should be mandatory and should include a review of likely effects on giant otters and other threatened species.
In local situations, it might prove necessary to devise means of reducing conflicts between giant otters and fisheries.
Much stricter regulations need to be enforced to prevent the escape of toxic wastes from factories, human settlements, or agriculture into rivers and wetlands. Of immediate concern is mercury pollution in the Amazon basin arising from gold washing. It is also recommended that the use of certain persistent chemicals, such as organochlorines, be phased out.
This species requires continued strict legal protection throughout its range. In many areas, enforcement needs to be improved, especially in relation to illegal hunting, and efforts to eliminate the illegal trade in pelts should be maintained.
Public education campaigns are needed in all countries within the range of the giant otter to draw attention to the plight of this species, and to develop support for its conservation.
There should be initial attempts to keep and breed this species in captivity, with a view to starting a coordinated captive breeding program.
Giant otter (Pteronura brasiliensis) (Photo by Russell Mittermeier).
This species is threatened within its known range, the Pacific coasts of Argentina, Chile, and Peru. Conservation priorities are:
Field surveys, using standard methods, should be conducted throughout the range of this rare species to determine current distribution and status. Priority areas for such surveys are: Staten Island in Argentina; the entire coastline of Chile; and the Peruvian coastline south of 6° S. Such surveys should be most efficient if they concentrate in the first instance on areas of suitable rocky habitat. These surveys should develop into regular monitoring programs.
Studies on the ecology and conservation requirements of this poorly-known species should be continued. Such studies should seek to identify those habitat features that must be conserved if this rare species is to survive and recover its numbers. Research is also needed on food requirements, and the impact of human activities (such as harvesting of marine resources, including algae) on the marine otter needs evaluation.
Coastal protected areas need to be established for this species in all three countries. Management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Even outside protected areas, this species requires strict protection from hunting and persecution in order to prevent the fragmentation of populations. Continued efforts are needed to eliminate the illegal trade in pelts.
In local situations, it might prove necessary to devise means of reducing conflicts between marine otters and fisheries, most notably with prawn harvesters in Peru.
The effects of inshore pollution of various forms on the marine otter also need to be evaluated, and if necessary, there should be stricter controls on the discharge of pollutants into the sea. In particular, much tighter controls are needed on mining activities in northern Chile (that have been causing severe inshore heavy metal pollution).
Public education campaigns are needed in all three countries within the range of the marine otter to draw attention to the plight of the species, and to develop support for its conservation.
There should be initial attempts to keep and breed this species in captivity, with a view to starting a coordinated captive breeding program. In the long term, the possibility of reintroducing the species in parts of the former range might be considered.
This species is restricted to Argentina and Chile, and is threatened in both. Conservation priorities are:
Field surveys, using standard methods, should be conducted throughout the range of this rare species to determine current distribution and status. Priority areas for such surveys are: Staten Island and the Nahuel Huapi basin and surrounding areas in Argentina; and suitable areas of freshwater and marine habitat in Chile south of 36° S. Such surveys should be most efficient if they concentrate in the first instance on areas of suitable habitat. These surveys should develop into regular monitoring programs.
Studies on the ecology and conservation requirements of this poorly-known species should be continued. Such studies should seek to identify those habitat features that must be conserved if this rare species is to survive and recover its numbers. Research is also needed on food requirements, and the impact of human activities such as harvesting of marine and freshwater resources (including algae), on the southern river otter needs evaluation.
Coastal and inland protected areas need to be established for this species in both countries. Management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above. There should be close cooperation between Argentina and Chile in implementing conservation programs for this species.
Even outside protected areas, the habitat of the species needs careful management to prevent population fragmentation. The clearance of large areas of forest in southern Chile, and of riparian vegetation in central Chile, is of particular concern and needs to be carefully regulated.
This species requires strict protection from hunting and persecution in order to prevent the fragmentation of populations. Continued efforts are needed to eliminate the illegal domestic trade in pelts, and this is another issue which depends on close cooperation between Argentina and Chile.
When major development projects are being considered (e.g. hydroelectric power development and agricultural expansion around rivers), environmental impact assessments should be mandatory and should consider the effects of such schemes on otters and other species of conservation concern.
In local situations, it might prove necessary to devise means of reducing conflicts between southern river otters and fisheries.
The effects of pollution of various forms on the southern river otter also need to be evaluated, and if necessary, there should be stricter controls on the discharge of pollutants into the sea. Particular points of concern include freshwater pollution in central Chile.
Public education campaigns are needed in both countries to draw attention to the plight of the species, and to develop support for its conservation.
There should be initial attempts to keep and breed this species in captivity, with a view to starting a coordinated captive breeding program. In the long term, the possibility of reintroducing the species in parts of the former range might be considered.
Though still widespread throughout its extensive range from Mexico south to Argentina, it is thought to be declining in many areas. Conservation priorities are:
Field surveys, using standard methods, should be conducted in each of the 21 countries in which the Neotropical otter occurs to determine current distribution and status. These surveys should develop into regular monitoring programs.
Studies on the ecology and conservation requirements of this species should be continued. Such studies should seek to identify those habitat features that must be conserved if this species is to survive in good numbers.
Protected area management plans should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of forest, wetland and riparian habitats on a long-term sustainable use basis. There is also a need to integrate indigenous people and their needs into the conservation and sustainable management of the habitats of this species. When major development projects are being considered (e.g. dam construction, mining operations), environmental impact assessments should be mandatory and should include a review of likely effects on otters and other species.
In local situations, it might prove necessary to devise means of reducing conflicts between otters and fisheries.
Much stricter regulations need to be enforced to prevent the escape of toxic wastes from factories, human settlements, or agriculture into rivers and wetlands. Of immediate concern is mercury pollution in the Amazon basin arising from gold washing. It is also recommended that the use of certain persistent chemicals, such as organochlorines, be phased out.
This species is widespread and common in parts of its range, but its distribution is poorly known or unknown in several countries. Conservation priorities are:
Field surveys, using standard methods, should be conducted in each of the 14 countries in which the Asian smallclawed otter occurs to determine current distribution and status. These surveys should develop into regular monitoring programs. Information is particularly sparse from the following countries: Bhutan, Brunei, Burma, Cambodia, Laos, Nepal, and Vietnam. However, adequate data on which sound conservation strategies can be based are not available for any country.
Studies on the ecology and conservation requirements of this species should be continued. Such studies should seek to identify those habitat features that must be conserved if this species is to survive in good numbers. It is also necessary to determine whether or not the ecological requirements of this species vary in areas where it is sympatric with other otter species.
Protected area management plans should take the particular needs of this species into account. These needs should be identified by the research studies referred to above. There is probably a need to establish additional protected areas for this species, for instance in mangrove areas of Peninsular Malaysia.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of forest, mangrove, wetland, and riparian habitats on a long-term sustainable use basis. There is also a need to integrate indigenous people and their needs into the conservation and sustainable management of the habitats of this species. When major development projects are being considered (e.g. dam construction, mining operations), environmental impact assessments should be mandatory and should include a review of likely effects on otters and other species. Special management practices are required to ensure the survival of this species in paddyfields, where it plays a valuable role in the control of pests; this requires maintaining areas of shrubs and other dense vegetation to provide the necessary cover for the species in the paddyfields.
Much stricter regulations need to be enforced to prevent the escape of toxic wastes from factories, human settlements, or agriculture into rivers and wetlands. The use of pesticides should be monitored to determine their effects on this species and its food. It is also recommended that the use of certain persistent chemicals, such as organochlorines, be phased out.
Education campaigns are needed to promote support for the conservation of this species, targeting in particular farmers who need to understand the role played by the Asian smallclawed otter in controlling pests in paddyfields.
In many countries, better enforcement is needed of existing conservation measures, illegal hunting for domestic markets being one of the principal threats to the species. The trade in pelts from this species needs to be carefully monitored.
Methods need to be devised to reduce conflicts between otters and fishermen, and to minimize the loss of otters in fish traps.
Providing that the original causes of extinction have been removed, a reintroduction program for this species should be considered in Hong Kong.
Asian small-clawed otters (Aonyx cinerea) (Photo courtesy of the New York Zoological Society).
This is the most common of the Asian otters but it is in decline and absent from parts of former range. Conservation priorities are:
Field surveys, using standard methods, should be conducted in each of the 15 countries in which the smooth otter occurs to determine current distribution and status. These surveys should develop into regular monitoring programs. Information is particularly sparse from the following countries: Bhutan, Brunei, Burma, Cambodia, Iraq, Laos, Nepal, and Vietnam. Particular priority should be given to the disjunct population in Iraq. However, adequate data on which sound conservation strategies can be based are not available for any country.
Studies on the ecology and conservation requirements of this species should be continued. Such studies should seek to identify those habitat features that must be conserved if this species is to survive in good numbers. It is also necessary to determine whether or not the ecological requirements of this species vary in areas where it is sympatric with one of other otter species.
Protected area management plans should take the particular needs of this species into account. These needs should be identified by the research studies referred to above. There is probably a need to establish additional protected areas for this species, for instance in mangrove areas of Peninsular Malaysia.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of forest, mangrove, wetland, and riparian habitats on a long-term sustainable use basis. There is also a need to integrate indigenous people and their needs into the conservation and sustainable management of the habitats of this species. When major development projects are being considered (e.g. dam construction, mining operations), environmental impact assessments should be mandatory and should include a review of likely effects on otters and other species. Special management practices are required to ensure the survival of this species in paddyfields, where it plays a valuable role in the control of pests; this requires maintaining areas of shrubs and other dense vegetation to provide necessary cover.
Much stricter regulations need to be enforced to prevent the escape of toxic wastes from factories, human settlements, or agriculture into rivers and wetlands. The use of pesticides should be monitored to determine their effects on this species and its food. It is also recommended that the use of certain persistent chemicals, such as organochlorines, be phased out.
Education campaigns are needed to promote support for the conservation of this species, targeting in particular farmers who need to understand the role played by the smooth otter in controlling pests in paddyfields.
In many countries, better enforcement is needed of existing conservation measures, illegal hunting for domestic markets being one of the principal threats to the species. The trade in pelts from this species needs to be carefully monitored.
Methods need to be devised to reduce conflicts between otters and fishermen, and to minimize the loss of otters in fish traps.
This species is rare or very rare throughout much of its range, though locally common in restricted areas of Angola, Central African Republic, Congo, Kenya, Liberia, Malawi, Rwanda, Tanzania, Uganda, Zaire, and Zambia. Conservation priorities are:
Field surveys, using standard methods, should be conducted in the range of this uncommon species to determine current distribution and status. Priority areas for such surveys are the lakes and large river systems of central Africa, with the priority countries being listed above.
Studies on the ecology and conservation requirements of this poorly known species should be continued. Such studies should seek to identify those habitat features that must be conserved if this species is to survive in viable populations.
Improved protected area management is needed for all reserves in which the spotted-necked otter occurs, and management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat management practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the management of the great lakes and river systems of tropical Africa through broadlybased integrated management programs. Priority areas for this approach are Lakes Victoria, Tanganyika, Malawi, Edward, Kivu, Muhazi, Bulera, and Luhondo, and the rivers of the Zaire/Congo basin.
In local situations, it mights prove necessary to devise means of reducing the numbers of this species being accidentally killed in fish traps. Controls on hunting might also be needed for some of the more important populations.
Environmental education programs within the range of the spotted-necked otter should include mention of the special problems of otter conservation, in the context of wider issues such as high human population growth, unsound agricultural practices, overgrazing, erosion and siltation of rivers and lakes.
Cape clawless otter (Aonyx capensis) (Photo by David Rowe-Rowe).
This species is rare through much of its extensive range. Conservation priorities are:
Field surveys, using standard methods, should be conducted in the range of this uncommon species to determine current distribution and status. Priority areas for such surveys are countries in which resonable populations are known to occur: Guinea, Kenya, Liberia, malawi, Mozambique, Senegal, South Africa, Tanzania, Zaire, Zambia, and Zimbabwe. In some of these countries, such monitoring could be developed as part of regular monitoring programs on the health of wetland ecosystems.
Studies on the ecology and conservation requirements of this species should be continued. Such studies should seek to identify those habitat features that must be conserved if this species is to survive in viable populations.
Improved protected area management is needed for all reserves in which the cape clawless otter occurs, and management plans for these reserves should take the particular needs of this species into account. These needs should be identified by the research studies referred to above.
Habitat manamgement practices outside protected areas should also be carried out in such a way as to prevent population fragmentation. This implies the careful management of lakes, wetlands, and riparian habitats, perhaps concentrating initially on the countries listed above.
In local situations, it might prove necessary to devise means of reducing the numbers of this species being accidentally killed in fish traps. Controls on hunting might also be needed for some of the more important populations.
Environmental education programs within the range of the Cape clawless otter should include mention of the special problems of otter conservation, in the context of wider issues such as high human population growth, unsound agricultural practices, overgrazing, erosion, and siltation of rivers and lakes.
This widely distributed species has severely declined in much of western Europe, where it has recently received much conservation attention. Little is known of its status outside Europe. Conservation priorities are:
For the following countries basic information on current distribution is rudimentary and field surveys to determine current status and distribution are a priority: Afghanistan, Bangladesh, Bhutan, Burma, Cambodia, China, India, Indonesia (Sumatra), Iran, Iraq, Japan, Laos, Lebanon, Malaysia, Nepal, North Korea, Pakistan, Romania, South Korea, much of the Soviet Union, Syria, Taiwan, Thailand, Turkey, and Vietnam.
In the following countries distribution has been determined, at least in part, by field surveys. Priorities are to complete all unfinished surveys and/or to develop monitoring programs to assess future changes in status/distribution: Albania, Algeria, Austria, Belgium, Bulgaria, Czechoslovakia, Finland, France, German Democratic Republic, German Federal Republic, Greece, Hungary, Ireland, Israel, Italy, Jordan, Mongolia, Morocco, Netherlands, Norway, Poland, Portugal, parts of the Soviet Union, Spain, Sri Lanka, Sweden, Switzerland, Tunisia, United Kingdom, and Yugoslavia.
Coherent habitat management programs are needed for countries that are known to have viable populations. In some of these (e.g. Finland, Greece, Hungary, Indonesia, Ireland, Parkistan, Portugal, Spain, Sri Lanka, and Yugoslavia), conservation measures are inadequately defined at present, and national strategies need to be prepared and implemented. Such strategies should ensure that areas identified as priorities for otter conservation by national governments should receive protection from harmful development by these governments. In addition, grant-aided development schemes being funded by agencies such as the EEC should take care to respect national otter conservation strategies.
Nature reserve management plans should take the particular needs of the Eurasian otter into account. These needs should be identified by the studies referred to above. There is a need to establish additional protected areas for this species in most countries.
More research needs to be carried out on the extent of contamination with accumulating pollutants, both in otters and their food-chains, and trans-national cooperation between researchers and governments is required. Special attention should be paid to emerging water pollution problems in eastern Europe.
All developments likely to impact otters and their habitats (i.e. hydroelectric schemes, fish farms, and wetland drainage) should only proceed after having been subjected to environmental impact assessments, and subsequently modified to minimize risks to otter populations.
In local situations, it might prove necessary to devise means of reducing the numbers of this species being accidentally killed in fish and mammal traps. Controls on hunting might also be needed for certain populations, as well as the development of means to reduce conflicts between otters and fishermen.
Environmental education programs should be promoted throughout the range of the Eurasian otter, drawing attention to the plight of this species and promoting public support for its conservation.
Reintroduction programs might be considered in certain countries in which the species is now extirpated, provided that the original causes of decline have been removed. Countries for which such programs might be developed include Belgium, Hong Kong, Japan, Netherlands, and Switzerland.
Eurasian Otter (Lutra lutra) (Photo by Claus Reuther).
This species suffered population declines and loss of range, especially last century, mainly due to trapping for pelts. Conservation priorities are:
Critical evaluations of current status determinations are of highest priority for this species, especially in states and provinces where harvest is permitted. Exploitation should be permitted in those states or provinces that can scientifically demonstrate 1) that their otter population is stable or increasing, and 2) that the level of take is not jeopardizing the population. Consistent analytical procedures and decision criteria should be implemented by all states and provinces in which the species is harvested. A combination of methods, including the following, should be used in determining population status: density estimates, natality and recruitment estimates, age structure analyses, track and scat surveys, questionnaires, and harvest data analyses. Where possible, radio-tracking should be used to obtain population parameters and radioisotope tagging should be tested further as a means of obtaining density estimates.
Extensive and intensive studies of the distribution and relative abundance of the rare subspecies L. c. sonora in the Rio Grande, Colorado, and Canadian River drainages of the southwestern United States, and also in nearby Mexico, are urgently needed. In the interest of maintaining genetic diversity, release of otters from other areas should be curtailed until the status of this subspecies is fully assessed. Additional studies of the North American river otter in the North American interior (e.g. Great Plains of southern Canada and midwestern United States) are needed.
Carcasses from the fur harvest and accidental deaths should be analyzed more often to increase knowledge of pollutants, reproductive biology, parasite load, diet, and taxonomy. A detailed and geographically comprehensive analysis of pollutant levels is needed.
Guidelines provided in Chapter 7 on reintroductions should be followed prior to release in order to avoid needless deaths of otters, waste of time and money, and genetic mixing.
All beaver management plans should be developed to safeguard otter populations as well. In areas where otters are endangered, the use of Conibear traps should be prohibited. Modified leg-hold traps or Hancock live traps should be used in areas where beavers have become a nuisance and otters are endangered, taking into account any new developments in trap technology to make these more humane. Education and enforcement programs should be instituted to ensure that these guidelines are met.
Cooperative studies with aquatic biologists are needed to determine the North American river otter's habitat requirements, prey preferences, and role in the ecological community.
Cooperation is needed between neighboring states and provinces in studies of North American river otters within major drainage systems.
A concerted effort should be made to refine and publish final reports in order to disseminate the latest knowledge on the species.
A symposium on the ecology of the North American river otter is needed to synthesize current knowledge and to provide direction for future research and management. The last one was held in 1984 in Columbia, Missouri.
Once on the verge of extinction, this species has made a remarkable recovery due to protective legislation and considerable governmental funding for scientific studies and conservation action. More is known of the distribution and numbers of this species than any other otter. Nevertheless, the recent oil spill in Prince William Sound, Alaska, has shown how populations remain vulnerable to such catastrophes.
Management and recovery plans should be developed and implemented for the Asian populations.
Reintroduction programs should be considered for parts of the former range in which the species is still absent (i.e. Japan and Mexico). Californian populations also need strengthening through reintroductions and restocking.
Traditional hunting of the species in Alaska should be managed under a program of carefully regulated and scientifically defendable quotas.
Sea otters found dead in California should be examined for contaminants which might pose a threat to long-term population viability.
Means need to be found to resolve perceived conflicts between fisheries and sea otters.