INFORMATION AND CHARACTERISTICS.

This dolphin is one of two species of the genus Lissodelphis. It is a toothed cetacean found only in the southern hemisphere. Bernard Germain de LacépèdeIt described this species in 1804 based on a specimen he saw near the island of Tasmania.

PHYSICAL DESCRIPTION.

Morphology.
This dolphin has the thinnest body of all cetaceans. Its body, incredibly hydrodynamic, is similar to the one of the northern right whale dolphin (Lissodelphis borealis) with a slender shape, a short snout and lacking the dorsal fin. It has a tilted forehead instead of rounded like most species and pectoral flippers with a sickle shape.

Weight and size.
The adult dolphin measures 1.8-2.9 meters in length and weighs between 60 and 100 kilograms. The sexual dimorphism is very slight, being the male bigger than the female.

Order: Cetacea
Family: Delphinidae
Genus: Lissodelphis

Skin Coloration.
The body of this cetacean is bicolor. The dorsal area is black from the forehead to the tail lobes. The white color starts from the snout and continues to the belly and up to the middle of both sides. The pectoral flippers are usually gray, and some individuals exhibit small white patches on the head.

Distinctive characteristics.
Their coloring pattern and the lack of dorsal fin are the main distinguishing features. There may be confusion with the northern right whale dolphin because they have a similar appearance, but the difference between them lies in the fact that the sides of this dolphin are entirely black, and the snout is not white as the southern species. Besides, the distribution area of each species is far from each other.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

It has a circumpolar distribution only in waters of the southern hemisphere, between the Antarctic Convergence and the Subtropical Convergence. Its limits are between latitudes 30° south and 65° south, being the north of Peru the northmost limit of its distribution.

It is present in countries such as Australia, Chile, Argentina, New Zealand, Uruguay, South Africa, Mozambique, and Peru.

It is a pelagic dolphin that prefers high seas and only approaches the coasts if the waters are deep on the edge of the continental shelf. The temperatures of their cold habitats range between 1° and 20° Celsius degrees.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Studies of the stomach of specimens of this species report a carnivorous diet in which mesopelagic fish, crustaceans, and cephalopods have preponderance. Their preys commonly inhabit depths between 200 and 1,000 meters.

Given its thin and hydrodynamic body, most scientists think that this dolphin is quick and agile to capture its prey, but if it feeds on the surface or in lower layers of the water column, it is still unknown.

Some of its favorite prey are lanternfish (Myctophidae), bigeye tuna (Thunnus obesus), squid, shrimp and species of the family Euphausiacea, which includes several species of krill.

HOW DO THEY BEHAVE? BEHAVIOR

It is a highly gregarious species which the creation of pods influence its social and individual behavior. A pod of Lissodephis peronii is usually composed of more than 100 members and may have up to 1,000 members. However, the average number of dolphins in a group is around two hundred.

If a dolphin is alone without company, it shows a relative shyness and avoids the ships. On the other hand, if a dolphin is with its pod, it shows more activity and dynamism. They can jump and hit the water with their belly or tail and create disturbances on the surface of the ocean due to the massive number of individuals in the pods.

Pods usually submerge for more than 6 minutes, but a single dolphin only dives for a very short time, so it tends to surface every 10 seconds or so. When swimming slowly, it only keeps the spiracle and part of the head out of the water; this is usually done while resting or during periods of low activity.

To date, there is no significant data on the existence of migration patterns, although it is likely that during the spring and summer they move northwards.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

There is a lack of information about most of the breeding habits of the southern right whale dolphin, but research suggests that males reach sexual maturity when they have a length of 2.51 meters and females are sexually mature with an approximate length of 2.18-2.28 meters.

The birth season is not known although in winter and spring more calves are seen, so perhaps the births occur around those seasons.

A calf can measure 0.86 meters in length and weigh about 5 kilograms at birth. Its longevity is approximately 42 years in the wild.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: Data Deficient.

It is true that there are more doubts than confirmed facts about this species. In fact, not even the International Union for Conservation of Nature (IUCN) has sufficient data to assess its conservation status which has a “Data deficient” classification due to the lack of information about the species.

However, this does not mean that the southern right whale dolphin is out of danger as this species has several threats, most of them derived from human activities. In Peru and Chile they have been caught for consumption, and in other regions, bycatch is common when these cetaceans become entangled in gillnets, particularly those trying to catch swordfish.

There are no specific conservation efforts for the Southern right whale Dolphin yet, but CITES has included it in Appendix II of endangered species where this organization lists the animals whose commercial trade must follow strict regulations.

References

Jefferson, Webber, Pitman. Marine Mammals of the World: A Comprehensive Guide to Their Identification. Academic Press, 2015. Page 306.

http://www.iucnredlist.org/details/12126/0

http://www.cms.int/reports/small_cetaceans/data/L_peronii/l_perronii.htm

http://www.fao.org/fishery/species/18218/en

INFORMATION AND CHARACTERISTICS.

The Northern right whale dolphin and its close relative the southern right whale dolphin (Lissodelphis peronii), are the only dolphin species of the family Lissodelphis that lack a dorsal fin. The naturalist Titian Peale was the first to describe this species in 1848. Its scientific name comes from word Lissos that means “soft” in Greek, and the Latin borealis which means “north.”

HOW DO THEY LOOK? PHYSICAL CHARACTERISTICS.

Morphology.
The slender, hydrodynamic body of the northern right whale dolphin allows it to reach great speed when swimming. Both species of the genus Lissodelphis are the thinnest of all the small cetaceans, and this, in particular, is endowed with a short “snout” and a tilted forehead, both separated by a fold. It has no dorsal fin but has two small, curved and pointed pectoral flippers.

Order: Cetacea
Family: Delphinidae
Genus: Lissodelphis

Weight and size.
Usually, males are larger and heavier than females. An adult male individual measures approximately 3.1 meters in length but the range of the female is 2.3-2.6 meters. The weight oscillates between 60 and 100 kilograms.

Skin Coloration.
The shining dolphin’s skin has a dark color on the dorsal area that contrasts with the white belly, however, this is little visible. Under the lower jaw, it has a white spot. Both the pectoral flippers and the caudal fin are black.

Distinctive characteristics.
It is easy to distinguish this dolphin from other species, but it can be confused with sea lions because of the lack of dorsal fin. It is necessary to observe the dorsum and the coloring pattern characterized by black and white to avoid confusion with other animals.

WHERE DO THEY LIVE? DISTRIBUTION AND HABITAT.

The Northern right whale dolphin has a limited distribution. It is found only in temperate and cold waters of the North Pacific Ocean between latitudes 30° and 50° north. They inhabit from northern Baja California in Mexico to the Gulf of Alaska, and in the west from Kamchatka in Russia to Japan. It is present in Russia, Mexico, the United States, Canada, and Japan.

It inhabits waters of the platform and the continental slope of great depth as well as (occasionally) areas near the coasts as long as they are deep. The temperature of its habitat is generally below 19° C but can tolerate those equal to or less than 24° C.

WHAT DO THEY EAT? DIET AND EATING HABITS.

Fish and cephalopods make up most of the diet of this carnivorous dolphin. It feeds on a wide variety of species. Some of its favorite prey are:

– Lanternfish (myctophids).
– Hake.
– Saury (family Scomberesocidae).
– Octopus.
– Squid.

When they inhabit around the center of the Pacific Ocean, the lanternfish make up the prey most consumed by this dolphin.

HOW DO THEY BEHAVE? BEHAVIOR.

The Northern right whale dolphin is very gregarious and creates pods quite large. They are comprised of 100-200 dolphins although the most common number is 200. However, sometimes they form superpods up to 2,000-3,000 individuals. The organization of such pods is somehow similar to some birds; they can travel forming a V.

It often associates with other dolphins and marine mammals, especially the Pacific white-sided dolphin (Lagenorhynchus obliquidens) and the Risso dolphin (Grampus griseus). It swims very fast, and its average speed is about 25 kilometers per hour, but it has speed bursts up to 40 kilometers per hour.

Sometimes the pod creates disturbance in the surface of the water due to its acrobatics, jumps, splashes with the tail and belly. It is also a little nervous and if something disturbs it, then flees immediately.

There are reports of seasonal migrations triggered by changes in water temperature. During spring and summer, the southernmost individuals travel to the north, and the northern ones migrate south.

HOW DO THEY REPRODUCE? MATING AND REPRODUCTION.

Data on the reproductive habits of this cetacean are very scarce. They reach sexual maturity between 9.7 and 9.9 years of age, being the later in males. In the winter-early spring period, there is more birth frequency, but other researchers believe that most births occur during the summer months, between July and August.

The female gives birth every 2 or more years to one offspring whose length is 0.8-1 meter.

WHAT IS THEIR CONSERVATION STATUS? THREATS AND CONSERVATION.

Conservation Status: “Least Concern.”

The conservation state of this dolphin is “Least Concern” on the Red List of the International Union for the Conservation of Nature (IUCN). A few years ago thousands of Northern right whale dolphins (Lissodelphis borealis) were killed annually in waters of Japan, Korea, and Taiwan as result of bycatch. Today, the number of deaths has reduced, but gillnets, direct harpoon hunting and contamination of its habitat still threaten the survival of this dolphin.

Efforts to preserve this dolphin involve its inclusion in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) and taking the measures recommended by the Pacific Offshore Cetacean Take Reduction Team of the National Marine Fisheries Service (NMFS) to reduce incidental fishing mortality.

References

Annalisa Berta. Whales, Dolphins, and Porpoises: A Natural History and Species Guide. University of Chicago Press, 2015.

http://www.iucnredlist.org/details/12125/0

http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/northernrightwhaledolphin.htm