William F. Perrin

Principles for the Conservation of Wild Living Resources

We describe broadly applicable principles for the conservation of wild living resources and mechanisms for their implementation. These principles were engendered from three starting points. First, a set of principles for the conservation of wild living resources (Holt and Talbot 1978) required reexamination and updating. Second, those principles lacked mechanisms for implementation and consequently were not as effective as they might have been. Third, all conservation problems have scientific, economic, and social aspects, and although the mix may vary from problem to problem, all three aspects must be included in problem solving. We illustrate the derivation of, and amplify the meaning of, the principles, and discuss mechanisms for their implementation. The principles are: Principle I. Maintenance of healthy populations of wild living resources in perpetuity is inconsistent with unlimited growth of human consumption of and demand for those resources. Principle II. The goal of conservation should be to secure present and future options by maintaining biological diversity at genetic, species, population, and ecosystem levels; as a general rule neither the resource nor other components of the ecosystem should be perturbed beyond natural boundaries of variation. Principle III. Assessment of the possible ecological and sociological effects of resource use should precede both proposed use and proposed restriction or expansion of ongoing use of a resource. Principle IV. Regulation of the use of living resources must be based on understanding the structure and dynamics of the ecosystem of which the resource is a part and must take into account the ecological and sociological influences that directly and indirectly affect resource use. Principle V. The full range of knowledge and skills from the natural and social sciences must be brought to bear on conservation problems. Principle VI. Effective conservation requires understanding and taking account of the motives, interests, and values of all users and stakeholders, but not by simply averaging their positions. Principle VII. Effective conservation requires communication that is interactive, reciprocal, and continuous. Mechanisms for implementation of the principles are discussed.

Stenella clymene, a Rediscovered Tropical Dolphin of the Atlantic

Stenella clymene has not been recognized as a valid species in recent lists of cetaceans. Examination of new material allows the redescription of this valid species. Externally, it closely resembles S. longirostris ; cranially, it resembles S. coeruleoalba in shape, but is smaller. S. clymene shares many features with these two species and is probably closely related to both of them. S. clymene is now known from New Jersey, Florida (both coasts), Texas, the Caribbean, the mid-Atlantic and West Africa. New records of S. longirostris extend its known range in the western Atlantic north to Cape Hatteras and south to Rio de Janeiro.

Movements of whale sharks (Rhincodon typus) in South‐east Asian waters as determined by satellite telemetry

Management of whale shark Rhincodon typus populations is hampered by a lack of information on the range travelled by individual whale sharks. This applies particularly in South-east Asia where the whale shark is increasingly used in commercial trade and for ecotourism. In this study an investigation of the movements of individual whale sharks from the greater Sulu Sea region was initiated using satellite telemetry. The movements of six sharks were monitored from 7 to 128 days. Two sharks travelled distances of 4567 and 8025 km. Both sharks moved through multiple political jurisdictions, confirming the need to manage the populations on a multilateral or regional level.

South American Sea Lion: Otaria flavescens

Publisher Summary The scientific name of the South American sea lion has been under discussion for many years. Two names were in use until a few years ago: Otaria flavescens and Otaria byronia. More recently, the use of O. flavescens has been recommended; this is the name used throughout the distribution area in South America. This species is one of seven that make up the subfamily Otariinae, part of the family Otariidae, usually called otariids, or pinnipeds with ears. It is one of the largest and most dimorphic otariids. Adult males are much heavier than females. South American sea lions are widely distributed along the Atlantic and Pacific coasts of South America: from Torres in southern Brazil to Cape Horn in the extreme south of the Atlantic coastline, and from Cape Horn to Zorritos in northern Peru, on the Pacific. The South American sea lion eats mainly demersal and benthic species, including fish and squid, but its diet is very variable and it adapts easily to locally abundant prey, including crustaceans and even penguins. Adult males and females arrive at the breeding rookeries during the first half of December. The males defend a position on the central breeding area, and during the peak of the breeding season they also defend females in estrus. In other rookeries such as Puerto Piramide, males defend the territories where females go to mate. The sex ratio at birth is 1:1. Males become sexually mature in their sixth year of age, whereas females produce their first offspring about the fifth year or before. The reproductive behavior of marked individuals was studied for 10 years at Punta Norte rookeries in Peninsula Valdes, Argentina. Human exploitation has been hard on pinnipeds. Some species were hunted down to extinction or barely survive, whereas others were spared thanks to the remoteness of their location, as the Antarctic phocids and the fur seals at Patagonian islands. Pinnipeds in general were killed to obtain oil, fur, and meat either for subsistence or for commercial purposes.

Pantropical Spotted Dolphin: Stenella attenuata

Publisher Summary The pantropical spotted dolphin can be identified externally by its long beak sharply demarcated from the melon, slender body, strongly falcate dorsal fin, and (in adults) spots. The newborn calf is unspotted. Dark spots begin to appear ventrally in large juveniles. Near-adult animals and some young adults have large discrete or overlapping spots both above (light) and below (dark). In adults, the ventral spots fuse and fade to a medium gray, and the dorsal light spots intensify, sometimes to the point of making the animal appear nearly white above. This species may be confused in the tropical Atlantic with the endemic Atlantic spotted dolphin, S. frontalis, which is of similar size and may be seen in the same area. A distinguishing characteristic of S. frontalis is a light spinal blaze that sweeps up through the cape toward the dorsal fin, but this may be almost absent in some individuals. In the eastern Pacific, the offshore form, S. a. attenuata, inhabits the tropical, equatorial, and southern subtropical water masses, being most abundant in waters underlain by a sharp thermocline at depths of 50 m or less, a surface temperature over 25°C, and salinities less than 34 parts per thousand. Prey of the offshore form includes mainly small epipelagic fishes, squids, and crustaceans. Flying fish are a major diet item in some regions. Spotted dolphins exhibit a wide variety of aerial behavior; juveniles make especially high vertical leaps. Pantropical spotted dolphins have been implicated in depredation on or interference with hook-and-line fisheries for squid and fish in Japan, and 538 were culled during the period 1976–1982.

Blue Whale: Balaenoptera musculus

Summary Blue whales are the largest creatures on Earth, and probably the largest creatures to have ever existed on Earth. They occur in all oceans, with three subspecies currently recognized. They feed on euphausiid crustaceans, close to primary productivity. They make infrasonic sounds that reach to hundreds of kilometers, and may communicate effectively over long distances in an ocean basin. Social/sexual strategies have not yet been fully described.

Spinner Dolphin: Stenella longirostris

Summary The spinner dolphin is the most commonly seen dolphin in tropical pelagic waters, as it leaps and spins in the air. There are several recognized subspecies. The skull is similar to that of several other small delphinids. It can be very abundant, with regional populations of up to hundreds of thousands. Habitats vary from shallow waters around islands to the high seas. Prey consists mostly of small fishes and squids. Predators include sharks and some smaller toothed whales. The reason for the spinning behavior is unknown. Sexual maturity is reached in females at about 8–9 years and in males at 7–10 years. Gestation is about 10 months. The mating system may vary among populations. Large numbers have been killed as bycatch in the tuna purse seine fishery of the eastern tropical Pacific; one population has been reduced to half its original size. They are also hunted and taken as bycatch in many other regions.

Whaling as Science

In an open letter published last year in the New York Times, 21 distinguished scientists (including three Nobel laureates) criticized Japan’s program of scientific research whaling, noting its poor design and unjustified reliance upon lethal sampling. In a recent Forum article in BioScience, Aron, Burke, and Freeman (2002) castigate the letter’s signers and accuse them of meddling in political issues without sufficient knowledge of the science involved in those issues. As members of the Scientific Committee (SC) of the International Whaling Commission (IWC), we can attest that the signers of the open letter correctly summarized criticisms made by researchers very familiar with Japanese

Bryde's Whales: Balaenoptera edeni/brydei

Publisher Summary This chapter describes the Brydes whale, least known of the large baleen whales. Brydes whales are medium-sized balaenopterids. They were long confused with sei whales ( Balaenoptera borealis ) because of morphological similarities; this confusion lasted into the 1970s. Brydes whales were first described based on examination of a stranded balaenopterid on Thaybyoo Creek beach, Gulf of Marataban, Burma. Females are larger than males throughout life, by about 2 ft (0.5–0.6 m) at full maturity. It is believed they reach 15.5 m, but most are much smaller. As demonstrated for South African Brydes whales, animals from coastal stocks or stocks inhabiting rather areas are generally smaller than those from migratory pelagic stocks . Southern Hemisphere animals are also larger than Northern Hemisphere animals. In the South Africa and western North Pacific stocks, body length increases rapidly until 4–5 years, reaches about 90% of asymptotic length for both sexes at about 10 years, and ceases to increase at about 20–25 years. If mean lengths at physical maturity in the western North Pacific stock are substituted into the equation, weight estimates are 15.0 (at 13.0 m) and 16.6 (at 13.5 m) tons for males and females, respectively. Brydes whales do not gather into large groups. They are usually seen singly or in groups of 2–3 in the North Pacific, with a maximum group size of 12. Although Brydes whales have a life history similar to that of other balaenopterids, there are species-specific aspects due to the fact that they remain in tropical and temperate waters throughout the year.

The evolving male: spinner dolphin (Stenella longirostris) ecotypes are divergent at Y chromosome but not mtDNA or autosomal markers

The susceptibility of the Y chromosome to sexual selection may make this chromosome an important player in the formation of reproductive isolating barriers, and ultimately speciation. Here, we investigate the role of the Y chromosome in phenotypic divergence and reproductive isolation of spinner dolphin (Stenella longirostris) ecotypes. This species contains six known ecotypes (grouped into four subspecies) that exhibit striking differences in morphology, habitat and mating system, despite having adjacent or overlapping ranges and little genetic divergence at previously studied mtDNA and autosomal markers. We examined the phylogeographic structure for all six ecotypes across the species range (n = 261, 17 geographic locations) using DNA sequences from three Y chromosome markers, two maternally inherited mitochondrial (mtDNA) markers, and a biparentally inherited autosomal intron. mtDNA and autosomal analyses revealed low divergence (most ΦST values <0.1) between ecotypes and geographic regions, concordant with previous studies. In contrast, Y intron analyses revealed fixed differences amongst the three most phenotypically divergent groups: S. l. longirostris vs. S. l. roseiventris vs. combined S. l. orientalis/S. l. centroamericana/Tres Marias ecotypes). Another ecotype (whitebelly), previously postulated to be a hybrid between the two phenotypically most divergent ecotypes, had Y haplotypes from both putative parent ecotypes, supporting a hybrid designation. Reduced introgression of the Y chromosome has previously been observed in other organisms ranging from insects to terrestrial mammals, and here we demonstrate this phenomenon in a marine mammal with high dispersal capabilities. These results indicate that reduced introgression of the Y chromosome occurs in a wide taxonomic range of organisms and support the growing body of evidence that rapid evolution of the Y chromosome is important in evolutionary diversification.