Common name: Spinipinne porpoise
HABITAT AND GEOGRAPHICAL DISTRIBUTION
There Phocoena spinipinnis, known as spinipinne porpoise, is found only along the coasts of South America, starting from the southern part of Brazil, to continue along the coasts of Uruguay, Argentina, Chile and Peru.
It is not certain that it is present continuously along all the aforementioned coasts also considering the fact that we are dealing with a very different range of temperatures: in the southern part of Cape Horn and in Tierra del Fuego the water temperature varies from 3 ° C in June to about 9 ° C in the summer months; going up north there are more temperate waters up to the Gulf of San José in Argentina, where the water reaches temperatures of 19.5 ° C.
Usually it inhabits shallow waters, usually within 150 m of depth and are also found at the mouths of rivers. Along the coasts of Tierra del Fuego it has been seen that it is also found within the algae line.
It has been observed that, contrary to expectations, there is a greater population along the coasts of the Pacific Ocean rather than the Atlantic Ocean despite the latter having a much wider continental shelf. This fact is explained considering that in the Atlantic coast the Phocoena spinipinnis it has greater competition for food and therefore tends to be concentrated along the coasts of the Pacific Ocean.
There Phocoena spinipinnis compared to other species it is easily recognized as it has a particular dorsal fin: it is placed very distally, with respect to the head, and is particularly curved backwards and rich in tubercles along the anterior edge from which it takes its name spinipinnis "Spina" (from the Latin) and from which the Spanish name of this cetacean derives marsopa espinosa which means "thorny porpoise".
It is a very small porpoise, not exceeding 1.4 - 1.8 m in length (males are slightly larger than females).
The color is dark, black or gray particularly accentuated on the back which gradually becomes lighter as you move on the belly.
Like all porpoises it does not have the classic dolphin-beaked snout but remains short and with the head more similar to a cone.
A distinctive feature compared to the other species is to have a light gray halo around the eyes and have a dark colored stripe starting from the chin and stripes in the ventral part.
CHARACTER, BEHAVIOR AND SOCIAL LIFE
There Phocoena spinipinnis it is a very shy cetacean that immediately moves away when a boat tries to approach and perhaps in consideration of this fact, it is one of the least known and studied species.
It has been observed that they do not live in large groups, no more than eight individuals and are not particularly "noisy" in the sense that they do not perform acrobatic jumps out of the water, on the contrary they swim very discreetly and silently. They seem to tend to approach the coast after dark.
The maximum speed recorded was 4 km / h.
There Phocoena spinipinnis it feeds mainly on anchovies, hake, squid and shrimp.
REPRODUCTION AND GROWTH OF THE SMALL
The reproductive season is between June and September with a gestation period of about 10 months at the end of which small about 40 cm long are born.
Sexual maturity occurs when the young (males or females) reach a length of about 1.5 m.
The only known natural predator of the Phocoena spinipinnis is the orca.
STATE OF THE POPULATION
There Phocoena spinipinnis is classified in the IUNC Red list (2009.1) among animals with insufficient data, DATA DEFICIENT (DD) for which therefore it is not possible to make any type of evaluation.
Although we do not have precise data on the population of this cetacean, it is certain that many specimens are killed every year to be used as bait for crab fishing in the southern part of Chile. Also in Peru this cetacean is widely fished with nets to be intended for human consumption. The number of catches along the coasts of Peru has been estimated at 450 individuals per year, a number that is starting to cause serious concern. Even incidental catches with fishing nets along all coasts, especially fixed gillnets, begin to cause perplexity given the increasing reports.
There was only one study on the influence of pollution on the mortality rate on this cetacean which found that out of eight animals captured off the coast of northern Argentina, organochlorine levels were low, an almost foregone conclusion in line with the relatively low degree of pollution of those waters.
The species is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known simply as Washington Convention) which includes species not necessarily threatened with extinction, but whose trade must be controlled in order to avoid exploitation incompatible with their survival.
SOCIAL, ECONOMIC AND ECOSYSTEM IMPORTANCE
The meat of the Phocoena spinipinnis it is widely used both for human consumption and to obtain fishing bait.Note
(1) Image taken from Gobierno de Chile - Subsecreteria de pesca