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The Valdes Peninsula and its areas of influence have a predominant plateau configuration that takes up 90% of the total area, the remaining 10% consisting of closed basins (salt marshes) and coastline with cliff, sand and rolling stone beaches. Chubut Northwestern region is a cold semidesert climatic zone with an average annual rainfall of 150 to 200 mm. The Peninsula itself has, however, the characteristics of an island due to the presence of the Nuevo and San Jose Gulfs which lend it better hydric conditions than those prevailing on the wholly continental lands, with a consequent increase in its vegetation.
These differential marine and land conditions have favored the development of an extraordinary fauna potential turning it into a place of great importance for conservation and tourism. The region is influenced by the Southern limit of the woodland phytogeographical area represented by many shrub species and birds and mammals adapted to arid climates such as mara (Patagonian hare), cuis and copetona (small emu). Other species cover much larger areas and live under more diverse conditions over the whole of Patagonia, such as the Guanaco (lama guanicoe), the Gray Fox, Choique (rhea) and the Patagonian Skunk.
Marine birds
Which birds reproduce in the zone?
Almost every species reproduces in Patagonia except:
The Snowy Sheathbill (chionis alba), that reproduces in the Antarctic Peninsula and subantarctic islands.
The Sanderling (calidris alba), that reproduces in the Northern hemisphere and migrates over 11,000 kilometers to the South.
Reproductive seasons vary:
Spring: Magellan Penguins (spheniscus magellanicus) and most birds.
Summer: many birds continue their spring reproductive season.
Which species migrate?
The Magellan Penguins during the Autumn and Winter.
The Sanderlings migrates to the Northern hemisphere between March and July.
Which are more abundant?
Kelp gulls, Magellan penguins.
Coastal and Marine Birds
Kelp Gull
An abundant species that reproduces in coastal areas although it also flies hundreds of kilometers away from the sea.
It feeds on fish and small invertebrates such as crabs and small mussels.
It also eats eggs and newborns of other marine bird species and obtains part of its food in urban rubbish dumps.
Southern Giant Petrel
An adult male can weigh up to 5 kg.
The span between the end of the extended wings can reach 2 mts.
It has an excellent sense of smell that helps it to find food in the coast: dead penguins, sea lions and elephant seals. It does not always eat carrion but sometimes kills penguins to feed itself.
Black-browed Albatross
Its extended wings cover a span of over 2 mts.
In Argentina it only nests in the Malvina Islands and Tierra del Fuego.
The reproduction cycle of this species lasts 8 months (as compared to 2 - 3 months for other species).
Many die in the open sea caught in fishing nets.
Two-banded Plover
It can be distinguished from other varieties by a double dark band on its chest.
It weighs only 65 grams, the approximate weight of a hen egg.
During the winter it migrates from Patagonia to Uruguay and the South of Brazil.
This bird feeds on marine worms and other invertebrates living in the sand.
American Oystercatcher
A bright orange ring around the eyes distinguishes it from the Magellanic Oystercatcher (haematopus leucopodus).
The other species found in Argentina is the Blackish Oystercatcher (haematopus ater).It builds nests in the ground that are difficult to see. They are very territorial, faithful to their mates and the nesting place.
Large Maca
It has a long thin beak and neck.
It reproduces in fresh water, on river, lake and pool shores. At sea, it is always seen close to the coastline, outside its reproductive season.
It dives for fish and crabs to feed on.
Imperial Shag
It is distinguished from other cormorant species by its blue eye ring and white neck.
It dives down to over 50 m depths and feeds on fish.
It builds large nests on the ground, covered with seaweed, which it uses for several reproductive seasons.
Snowy Sheathbill
It has the appearance of a white dove but does not belong to this group of birds.
It nests only in the Antarctica Peninsula and SubAntarctic islands.
Curious, a great walker, it rarely settles on the sea.
It feeds solely on the ground, eats dead animal remains and robs food from other marine birds.
South American Tern
It is the most common tern in the Argentine coasts. Its V-shaped tail distinguishes it from the other two tern species that reproduce in Patagonia.
It feeds on fish near the coast, flies low over the sea and plunges to capture its prey.
Southern Right Whale
Generalities
There exist 11 species of whales two of which are known as Right Whales. The Southern Right Whale, eubalaena australis, lives in the Southern hemisphere and the Northern Right Whale, eubalaena glacialis, in the Northern hemisphere.
Whales are mammals and as such breathe air, maintain a stable body temperature and give birth to and nurse their young.
In spite of their size, Right Whales feed on small few millimeter long organisms.
The first whale hunters considered these whales to be the most appropriate ones for hunting because they move slowly, are easy to follow and to reach. Once dead, the Right Whales float (other species sink quickly) and render a large amount of oil, the main commercial product to be obtained therefrom.
Size & weight
Females are larger than males. They measure up to 16 meter long and an adult can weigh over 50 tons.
Distribution & abundance
They extend between 20’ and 64’ of Southern latitude.
The world-wide population is estimated to amount to just 3,000 individuals.
Conservation
During centuries and until some decades ago they were exposed to intensive hunting. Nowadays they are protected by international regulations.
The Southern Right Whale is threatened, whereas the Northern Right Whale is in danger of becoming extinct.
Familiar whales
The Right Whales bear natural marks that facilitate the identification of individuals.
Over 1,300 whales have been identified in Patagonia since 1970.
Whales arrival
The Right Whales arrive at the waters surrounding the Valdes Peninsula between March and May and reach their highest number during September and October. By the end of December almost all of them have migrated to the feeding areas.
Whales as individuals
The individual identification based on their natural marks started in 1970. It was discovered through aerial photography that individuals could be identified by their callosities (thickened rough skin found in some parts of the head and body).
Like a giant fingerprint, the callosity pattern remains unaltered throughout the animal lifetime.
Over 1,300 whales have been identified by their callosities. Approximately 130 adults are identified every year with about 30 calves being added to the list.
Some females have been seen in the Valdes Peninsula coasts for over twenty years.
The Patagonian population of Southern Right Whales is growing at an annual rate of 7.6% and is one of the most important world populations for a non-abundant species
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Biting and filtering cetaceans
Large whales, small preys
Mysticeta are in general larger than odontoceta. A Blue Whales (with 30 m long they are the largest-sized animals that ever existed) duplicates the length of a male sperm whale, the largest of all odontoceta.
In spite of their monumental dimensions, whales feed on small invertebrates that they filter in large amounts. The 16 m long, 60 ton Right Whale feeds on almost microscopic preys. These whales swim slowly with a slightly open mouth. Water enters their mouth from the front and exits from the sides. Food gets caught in the uneven edge formed by the 200-270 baleens that hang from the maxilla.
How do cetaceans feed?
Most of the species have teeth and belong to the odontoceta group. There exist approximately 65 species, commonly known as porpoises and dolphins. They feed on fish, squid and, in the case of orcas, on other marine mammals.
The other cetacean species do not have teeth. This group is composed of whales having baleens or mysticeta. The baleens consist of keratin, a material similar to that of nails. An individual possesses hundreds of baleens, in a side by side arrangement. The number and size vary according to the species but all serve to filter and retain food.
Right Interpretation
Some behaviors of the Right Whale are an enigma. A thorough study will be required to be able to interpret them, if possible at all.
Jump outside the water
It is one of the most spectacular behaviors developed by adults of both sexes, calves and young ones. The body emerges suddenly, almost vertically, while the tail remains submerged. The animal turns in the air and falls on its back or side.
The behavior is repeated in sequences of ten or more consecutive jumps.
Several whale species perform these acrobatics. The jump is a huge display of energy that generates an explosive noise when the animal strikes the water. Is it a remote communication signal?
Striking with the fins
The body remains partially submerged with the caudal fin (tail) outside the water. The whale bends the tail and strikes the surface of the sea with force. They perform the same movement with the pectoral fins.
Several individuals can carry out this behavior simultaneously. The noise they make is transmitted to a long distance both through the air and the water. Another form of communication?
Quiet tail outside the water
The whale remains vertically submerged with the caudal fin out of the water. It can remain in this position, practically motionless and without breathing, for 20 minutes. Is it resting? Or listening to other whales?
Generating descendants
Aloof females
The females mate on the year following the one they give birth. The males detect the sexually receptive females and follow them during hours. In order to mate, the whales must position themselves belly to belly.
Females can select the best reproductive males by adopting behaviors that make mating difficult. Sometimes a female swims in shallow waters, stays with the belly upwards or pushes the tail out of the water this position preventing the mating. The males compete, dive and push one another to place themselves underneath the female. Finally the female must breathe or decides to move away and then one or several males manage to copulate with it.
Maternal care
The newborns spend most of the time near the mother. Swimming, playing and resting are the most usual activities and only 5% of the day is dedicated to nursing.
Mothers and calves spend hours performing activities that might serve the latter as a practice of useful behaviors for other moments of their life. The calves play with seaweed uprooted by storms, buoys or ropes. However, playing has a cost. The calf spends energy playing and it is the mother who must provide it the food. Perhaps this is the reason why mothers sometimes interrupt the games of the young and avoid their interacting with other whales.
Southern Right Whale
The submarine messages of the right whales are emitted on a frequency range of about 50-2,100 Hertz and last from 1 to 2 seconds. Unlike the sounds of the humpbacks, they are not organized as a song. Part of the sound spectre is below the audible range for a human being and they possibly produce others on even lower frequencies than the ones found until now.
The richest and most complex sounds take place in the mating groups in which ten individuals move together but only one of them apparently makes sounds. There is no evidence that this or any other whale species use an echo location system for locating objects, as is the case with dolphins.
Dusky Dolphin
They live in the Southern hemisphere temperate zone. The color pattern varies from one individual to another as well as the dorsal fin shape. They can measure up to 2 meters long and weigh 90 kilos. They make up groups of from 6 to 15 individuals although during the feeding activities over 400 may gather. They approach the cost during spring and the beginning of summer, choosing deeper waters towards the end of the summer and autumn. Their displacements seem to follow the movement of their main prey: small anchovies and squid. They are accidentally caught in fishing nets.
Common Dolphin
They live in tropical and temperate waters all over the world. In some areas they can be seen all the year round.
They have a slender body and a prominent dorsal fin. Males, slightly larger than females, reach a
2.6 meter lenght and weigh up to 75 kilos. The newborns measure approximately 0.8 meters.
They gather in groups that sometimes consist of several hundreds of individuals, are fast swimmers and perform spectacular jumps out of the water. They can be usually seen swimming next to boat prows.
They feed on fish, cephalopoda and squid.
Some specimens are incidentally caught in fishing gear.
Commerson’s Dolphin
They can be seen in Patagonian coastal waters, the Malvinas, Georgias del Sur and the Southern end of Chile. They are also found in the Indian Ocean. Their body is small and the dorsal fin rounded. Adults are white and black but newborns are either brown or gray in color. They can measure up to 1.5 meters and both sexes weigh from 30 and 45 kilos.
They live in small groups of 2 to12 animals. They occasionally swim next to boat prows and visit ports. Tides are conveniently used by them to catch their prey which consists, among others, of squid and fish. They are illegally caught to be used as bait in spider crab traps. They get incidentally caught in coastal and deep-sea fishing gear.
Southern Elephant Seal
General information.
Elephant seals are seals.
The Southern elephant seal is the largest of the 19 seal species existing in the world.
It is one of the mammals having the greatest size difference between sexes: males can be five times larger than females.
One species in each hemisphere
There exist two Elephant Seal species: Mirounga leonina in the Southern hemisphere and Mirounga angustirostris in the Northern hemisphere.
Abundance
There exist around 700,000 Southern elephant seals in the world. The vast majority of groups are found in the Sub Antarctic islands. In Valdes Peninsula there are 12,000 new births per year and the total population amounts to 45,000.
Annual cycle in the Patagonia
They feed at sea.
They go on the shore only to rest, molt and reproduce.
Adults molt during the summer.
Calving and mating take place between September and November.
Olympic capacities
They fast during 100 days.
They dive constantly for months.
Ninety percent of their time at sea they remain under the water.
They get to 1,500 m depths and can remain submerged for two hours. Investment in the offspring.
Early reproduction
Southern elephant seal females can get pregnant for the first time at four years old. As from that moment, they give birth every year. After impregnation, the embryo development stops. Only after three months does implantation in the uterus take place and the embryo begins to take shape. This delay in implantation gives the mother enough time to replenish the energy reserves required for nourishing the foetus during its development.
No infancy
Calves are born eight months after implantation (eleven-month pregnancy) and nurse only for three weeks. Maternal milk has an exceptionally high fat content and it allows the newborn to rapidly increase its weight. Weaning takes place between 19 and 25 days after the birth and the calf becomes independent as from such early age. Approximately 19 days after starting nursing, the mother becomes sexually receptive and gets pregnant again. Except for those 19 days in the year, elephant seal females are permanently pregnant.
Prolonged fasting
Elephant seal femaless do not feed during the one-month reproduction and nursing period and lose 40% of their body weight. In this short period, the calves triple their weight. They are born weighing 40 kg and by the time they are weaned, they already weigh 130-150 kg.
While the young gains around 4 kg/day, the mother loses 9 kg/day.
Some calves nurse with more than one female and may weigh as much as 190 kg at the time of weaning.
Differences between Sea Lions and Seals
Seals are marine mammals that can be identified by the following characteristics:
• They have no outer ears. The external ear is just a small orifice located on both sides of the head.
• They move on the ground by means of undulatory movements of the body (crawling) driving themselves along only with their front fins. They cannot turn the rear fins forwards.
• They swim with the rear fins while maintaining the front ones stuck to the body.
• The front fin nails are near the edge of the fin.
• Nursing of the calves lasts from a few days to some weeks and weaning is abrupt.
Another group of marine mammals is that of the Otariidae or Sea Lions, whose characteristics are:
• Small triangular ears.
• They move on the ground using the front and rear fins. This givers them access to high platforms or rocks where elephant seals cannot reach.
• They swim driving themselves only with the front fins.
• They have nails in both fins but away from the edges.
• Nursing extends over months or even years and weaning is gradual.
The only representative of a seal species to be found along the Patagonian coast is the Southern elephant seal. South American sea lions and fur seals are otariidae. There are in all 34 species of seals and otariidae in the world.
South American Sea Lion
General information
Its scientific name is otaria flavescens.
It has a single layer of hair, this being the reason why it has been less attractive than the fur seal for the world-wide fur industry.
It feeds on different species of fish, squid and octopus.
Sexual differences
In all sea lion species the size and appearance of the males differ from those of the females of the same species.
Adult males have an extremely great head and neck. The hair on the neck is longer than on the rest of the body, thus giving them a lion appearance (hence the name). The males aggressively compete for the control of harems composed of reproductive females.
Size & weight
This is one of the largest species of sea lions.
Adult males can weigh up to 350 kg and be 2.3 m long.
Females do not exceed 200 kg.
Calves weigh at birth from 10 to 14 kg.
Distribution
They live on the South American coasts, from the south of Brazil to Tierra del Fuego in the Atlantic and up to the Equator in the Pacific. Over 100 groups have been described for the Patagonian coast.
Forty of them are reproductive and the remaining ones are either winter colonies or formed by yong animals.
The population estimated for the Patagonian coast is 70,000.
Conservation
During the first half of this century over 500,000 sea lions were killed along the Patagonian coast.
It is not uncommon for them to get caught in fishing nets and drown to death. An unknown number of animals die when getting entangled with ropes or pieces of net thrown into the sea.
About harems, mothers and offspring
Harem life
The South American Sea Lion reproduces between December and February.
Successful adult males reproduce with 5-10 females per season.
Females give birth to a single calf per season. Mating takes place six days after the birth.
Maternal care
As is the case with most mammals, females are the ones in charge of taking care of the offspring. Each female is pregnant on arriving at the beach and on the verge of giving birth, as a result of the previous mating season.
Since harems are not stable, it is unlikely for a male to be the father of the young born in its harem. Although adult males do not ill-treat those young individuals, they do not take care of them either.
Prolonged infancy
During the early months of their life, the survival of the young depends on maternal milk. As they learn to capture prey in the sea, they step into a mixed diet in which, in addition to milk, they include fish and invertebrates. Some young continue nursing after the first year.
Sea Lions do not adopt calves
Females usually nurse only their own young. A female that nurses other animal’s calves puts the life of its own offspring at risk. Consequently, a calf that loses its mother has few chances of surviving.
Orcas
General information
• Orcas (orcinus orca), are large sized dolphins.
• They are found in every sea of the world.
• The female average lifetime is 50-60 years.
• They give birth approximately every 10 years.
• Males generally die before reaching 30 years of age.
Size & weight
Males can be up to 9.5 meters long and weigh 8,000 kg.
Females rarely exceed 7 meters and 4,000 kg.
Bonds of kinship
They live in family groups formed by a male and several females, some young individuals and calves.
Born females remain in the family group. Thus, they are genetically related to the other females and the young males. Males leave the family group when they reach the reproductive age.
Predators and preys
They live on a varied diet: fish, penguins and other birds, marine turtles and mammals.
Orcas have a sophisticated predator behavior. They coordinate the attacks to their prey and can successfully hunt even great whales. Part of their success as hunters could be due to the communication they maintain under water by means of a varied sound repertoire.
Conservation
It is the most attractive species for aquariums, some of which have captured orcas from natural populations.
Orca (orcinus orca)
Like most toothed cetaceans, orcas emit complex high frequency sounds for situating themselves and communicating with other individuals.
They produce two types of sounds:
• Ample frequency band short pulse (0.8 to 25 thousandths of seconds) cracking-like sounds called “clicks” that are usually chain repeated for eco location purposes, a method which allows them to sail and find food by emitting sounds and receiving the echoes when the same bounce on submarine objects.
• 1.5 to 18 Khz whistling sounds lasting from 1 to 12 seconds, for communicating with other individuals.
As compared to orcas from other parts of the world, those that catch sea lions and elephant seals in Valdes Peninsula are quiet animals. Once the prey is caught the communication sounds increase, possibly to alert and attract the rest of the family group to the feeding place.
Magellan Penguin
General information
There exist 18 species of penguins living exclusively in the Southern hemisphere (only the Galapagos Penguins go as far as the Equator).
Penguins originated in flying ancestors but they lost such capacity in the course of evolution.
They are fast swimmers (almost as fast as dolphins) and dive to greater depths than other marine birds.
Two species reproduce in Patagonia: the yellow-tuft penguin and the Magellan one - Spheniscus magellanicus – which is the more abundant species.
Distribution and abundante
They reproduce in the coasts of South America, from Valdes Peninsula to Tierra del Fuego and the south of Chile. There exist 60 colonies on the Patagonian coast: approximately 890,000 reproductive pairs (1.800.000 animals) in Chubut, Santa Cruz and Tierra del Fuego. The Punta Tombo colony congregates more than 200,000 pairs.
Size, weight and colour
Length: 60 cm.
Adult weight: 4 to 5 kg.
Males are slightly larger than females.
Both sexes have the same coloring. Adults have a black back and white chest with a double black stripe.
Conservation
Contamination of the sea with oil and other hydrocarbons kills thousands of animals per year.
The fishing activity in some areas could affect penguin food availability.
Penguin calendar
September
To begin with, a good nest: the males arrive and compete for the best places to nest.
Feminine selection: two weeks later the females arrive and select a mate.
Some couples remain steady for life.
October
Laying: the female lays two eggs during a 1-4 day period. Incubation begins while the male is feeding at sea.
After 10-15 days, the male returns and starts its incubation shift.
November
First steps: the chicks hatch after 40 days of incubation. Chicks must be taken care of in order to maintain their bodily temperature. Parents alternate in this task.
December and January
Food on demand: both parents feed the chicks. By the end of December, chicks are left alone in the nest while both parents are at sea. Adults return to the colony for short periods to feed them.
Every year chicks die for lack of food and the predation of gulls, skuas and foxes.
February
Young individuals: these arrive to the colony to molt and practice the reproductive behavior. During molting they fast.
February and March
Metamorphosis: chicks change their down for the gray and white feathers that are characteristic of young individuals.
When molting is over, they go away to sea.
March & April
New costume: adults molt in three weeks, right after the reproductive season.
Between April and August
In the open sea: they leave the colonies from May to August. The apparently travel north, to the winter feeding areas, covering over 4,000 km between Patagonia and the Brazilian coast. This is the longest migration recorded for a nonflying bird.
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