Classification: The generic name, Pontoporia, refers to the belief - now found to be untrue - that this species moved from fresh to salt water. Blainville was a famous French naturalist.
Local Names: La Plata Dolphin; Toninha; Cachimbo
Franciscana is the best of many names for this tiny dolphin, also called the La Plata River Dolphin, toninha, and boto amarelo by fishermen in small villages that know it all too well from net entanglements. Found along the coast from the Province of Chubut, Argentina, to Espírito Santo State, Brazil, genetic and parasite studies suggest at least one isolated population of franciscana near Rio de Janeiro.
Description: The Franciscana is one of the world's smallest cetaceans. It has a long narrow beak which grows even longer with age, and a small but well-developed melon. The dorsal is small and triangular, with a rounded peak, and continues as a ridge down the tail stock. The flippers are broad and almost triangular in shape. Body colour is brown-grey, with paler undersides. Franciscanas measure between 1.3-1.7m in length, and weigh from 30-53kg.
Most babies are born between October and February, after a gestation period just over 11 months. Mothers with nursing calves tend to be in deeper waters than other franciscana. Fully weaned after seven months, still learning how to hunt for food but not knowing the dangers, these young franciscana are most vulnerable to becoming entangled in fishing nets.
Recognition at sea: The Franciscana can be readily identified by its small dorsal and long beak.
Habitat: Although related to the river dolphins, the Franciscana is a marine species which lives within 30m on the shore, in waters less than 10m deep.
The franciscana rarely swims in water deeper than 30 meters, catching squid, octopus, and many species of small fish. They use tidal currents in bays and estuaries for hunting, as many other species do worldwide. Their long jaws can be 15 percent of an adult's length, and with many small teeth are well suited to catching elusive prey in water so murky or turbid that a dolphin might not see another dolphin swimming right alongside. Although groups of up to 20 have been seen, probably brought together by rich hunting, the mean group size is only four dolphins.
Food & Feeding: These dolphins take fish, squid, crustaceans and octopus.
Behaviour: Little is known about Franciscana behaviour. They travel in groups of between 1-5 individuals.
Longevity: Approximately 18-20 years.
Estimated Current Population: Unknown.
The Influence of Man: There is no direct fishery for Franciscanas, but hundreds/thousands are killed annually in gillnets across all of their range.
BIBLIOGRAPHY:Balcomb, Kenneth; Minasian, Stanley, The World's
Whales. Illustrated by Larry Foster. A Complete Illustrated Guide. Smithsonian
Books, New York; W. W. Norton, 1983
Ellis, Richard, The Book of Whales. Alfred A. Knopf, New York, 1984
Folkens, Pieter A. (Illustrator), Randall R. Reeves, et al. National Audubon Society, Guide to Marine Mammals of the World. New York, NY: Alfred A. Knopf, 2002.
Leatherwood, S; Reeves, R. Whales and Dolphins. San Francisco; Sierra Club Books, 1983