Imprimir Republish


Whales and dolphins in sight!

Species diversity and animal abundance along the São Paulo coast are greater than imagined

Atlantic spotted dolphin: ongoing survey along the São Paulo coast

Eduardo CesarAtlantic spotted dolphin: ongoing survey along the São Paulo coastEduardo Cesar

Standing on the right side at the front of the motorboat that swung like a pendulum as it glided quickly along, Victor Uber Paschoalini was the first person to see something moving far off in the middle of the ocean around 11:00 on the morning of February 10, 2014, less than a kilometer from the island of Queimada Grande off the coast of the state of São Paulo. He thought they were dolphins—precisely what they were looking for. For confirmation, he called for the expedition’s leader, biologist Marcos César de Oliveira Santos, a professor at the Oceanographic Institute of the University of São Paulo (USP). They brought the boat closer in and got their confirmation: there were over 20 Atlantic spotted dolphins (Stenella frontalis), 2 to 2.5 meters in length, which then began to jump in the clear water alongside the boat. Santos asked the pilot to slow down, and he and his team photographed the animals—in particular their dorsal fins, which serve as identity cards because of the scars and unique marks on each individual—and recorded their sounds with a hydrophone placed in the water. Then, with an arrow fired from a crossbow, he collected a 1-millimeter-thick skin sample for genetic analysis, and a 2-centimeter fat sample for analysis of chemical contaminants.

It was the beginning of the fifth in a series of 23 expeditions, planned to take place between then and 2015, to map the diversity and distribution of cetaceans—whales and dolphins, also referred to as botos—along the São Paulo coast. Based on the dead animals they have found on the beach in recent years and the live ones they are seeing now, so far Santos and his team have recorded over 300 individuals from 29 species of cetaceans, which represent 63% of the 46 species observed to date along the Brazilian coastline. In rivers, there is less diversity of dolphins. A new species—the fifth on record—was given the name Inia araguaiaensis and announced in January by researchers from the state of Amazonas, who found it in the Araguaia River and its tributaries. Although they are seldom seen and rarely studied, cetaceans along the Brazilian coastline account for about half of the 87 species identified so far in the world’s oceans.

Flocking together: groups of up to 20 dolphins (here, Atlantic spotted) show up on the way to the island of Queimada Grande

Eduardo CesarFlocking together: groups of up to 20 dolphins (here, Atlantic spotted) show up on the way to the island of Queimada GrandeEduardo Cesar

The preliminary findings also suggest greater species diversity and abundance than had been imagined. They range from the La Plata River dolphin (Pontoporia blanivillei), one of the smaller freshwater mammals measuring up to two meters in length, which can be found from the state of Espírito Santo southward to Argentina and is often caught accidentally in fishing nets, to the colossal Bryde’s whale (Balaenoptera brydei), which can grow to a length of 15 meters.

These efforts are also generating new conclusions and hypotheses about the whales and dolphins that roam along the Brazilian coast. Comparing DNA samples, Santos and other researchers from USP, the Universidade Estadual Paulista (Unesp), Colombia and Puerto Rico have confirmed that the populations of Atlantic spotted dolphins found in southern and southeastern Brazil and the Caribbean are distinct from one another and do not mingle. A misconception about another species is also being cleared up. Bryde’s whales, a shy, nimble species that spend little time on the surface, apparently travel along the São Paulo coastline throughout the year, not just in spring and summer, as had been thought because divers saw them only during diving season.

Skin sample, for phylogenetic analysis

Eduardo CesarSkin sample, for phylogenetic analysisEduardo Cesar

Another possible and oft-used approach to mapping populations of cetaceans is to start from a fixed point. This is the approach used in the Abrolhos Archipelago, off the coast of the state of Bahia, to study humpback whales (Megaptera novaeangliae), one of the most widely distributed species throughout the world and the most extensively studied in Brazil because of its unique features. These include pectoral fins that can be up to a third of the animal’s body length, and its predictable spatial and temporal distribution: 80% of the humpback whales that visit the Brazilian coast are concentrated in the Abrolhos region, particularly from July to November, to give birth and feed their calves in warm, shallow waters. Biologist Salvatore Siciliano, currently with the National School of Public Health (Ensp), part of the Oswaldo Cruz Foundation (Fiocruz) in Rio de Janeiro, was there in 1989 and 1990 studying for his master’s degree and remembers “sitting on a rock with a clipboard and binoculars” and seeing 604 groups of humpback whales (half were females with calves) in 191 days of observation. At that time the only established marine mammal research terms were in Manaus, Amazonas, and Rio Grande, in the state of Rio Grande do Sul. Other groups were formed later on, but cetacean studies prior to 1980 are very rare, Siciliano recalls. This has made it difficult to do analyses and comparisons, unlike the situation with birds and land mammals, which have been studied for three centuries.

Daniela Abras, a researcher with the Oceanographic Institute at USP, was in Abrolhos in July 2013. With support from the Navy, the Jubarte Institute, the Chico Mendes Institute for Biodiversity Conservation (ICMBio) and Cetacean Society International (CSI), she sat at one of the highest points of the archipelago and recorded 500 majestic whales, considerably more than the 200 recorded in 2004. “The population of humpback whales has been growing as a result of the hunting ban, but their numbers are still far below what they were,” she says. Today the population of humpback whales is estimated at 7,900, and they can be seen along the coast from the Cabo Frio region in Rio de Janeiro State, northward to Rio Grande do Norte. That figure is well below the estimated population of 25,000 humpbacks before they began being aggressively hunted. As described in the book A baleia no Brasil colonial (The Whale in Colonial Brazil) by historian Myriam Ellis (Edusp/Melhoramentos, 1969), beginning in 1650 in the principal coastal cities, whaling was an important economic activity. Whales were the source of fish oil, used as building mortar and in public lighting, and whalebones, which were sold in Europe for manufacturing girdles. Boats 10 to 12 meters in length were used to harpoon and capture the whales, which were then killed with successive thrusts of two-meter-long spears, dragged to the beach and cut open. Each animal supplied 7,000 liters of oil on average. Not until 1987 did a federal law prohibiting whaling take effect.

Bottlenose dolphin, another species found along the São Paulo coast

Eduardo CesarBottlenose dolphin, another species found along the São Paulo coastEduardo Cesar

“This is the first time we are making oceanographic cruises specifically to map cetaceans along the 600-kilometer São Paulo coastline,” Santos says. “Before now, a lack of specialists and financial limitations meant that this work could only be done with dead animals,” Santos says. During his master’s program studies, Santos himself rode a bicycle or moped along the beaches of Cananeia and Ilha Comprida on the southern coast of São Paulo, collecting skulls of cetaceans he found dead. He gathered and examined a total of 124 skulls. For the first time a photojournalist—Eduardo Cesar from Pesquisa FAPESP—went along on one of the February trips and spent three days with the researchers at sea.

Two weeks before the trip, Santos, impressed with Paschoalini’s inquisitiveness in the classroom, invited him to round out his team on this expedition. But he never imagined the degree of luck that was in store for the young 19-year-old, now in his second year in the oceanography curriculum, whose right arm displays the Breton proverb, “Fight, and fight again, until lambs become lions.” The four team members took turns observing in one-hour shifts with half-hour rests, but it was Paschoalini who spotted the second group of dolphins two hours later. This time there were some 20 bottlenose dolphins (Tursiops truncatus), a different species slightly larger and less abundant than spotted dolphins, now in muddy waters under a bright sun.

Alongside Paschoalini, oceanographer Giovanna Corrêa e Figueiredo noticed that the animals, which are normally docile like the friendly Flipper in the old television series, were acting erratically. She thought they might be hungry and hurrying after a shoal of fish, or bothered by the water temperature of 30 to 33º Celsius—nearly five degrees higher than usual. Algae and other organisms proliferate more easily in warmer water and form a dark spot that hinders visibility, like the one in February on the coast between the states of Rio de Janeiro and Santa Catarina. On this and the next two days—as they traveled about 650 kilometers from São Vicente to llha do Mel, northern Paraná State—they kept their eyes on the ocean, gazing from bow to stern, even with the sun reflecting on the late afternoon water, but there were no further dolphin or whale sightings. “Sometimes you get so fatigued that you see a wave and think it’s a dolphin,” Figueiredo comments.

Beach at the port of Imbituba, Santa Catarina, late 1940s: unchecked slaughter of southern right whales

JOÃO HIPÓLITO DO NASCIMENTO / IMBITUBA WHALE MUSEUM COLLECTION Beach at the port of Imbituba, Santa Catarina, late 1940s: unchecked slaughter of southern right whalesJOÃO HIPÓLITO DO NASCIMENTO / IMBITUBA WHALE MUSEUM COLLECTION

She has accompanied Santos since the first expedition in December 2012. On that first day, they and other researchers in the group explored the ocean without seeing any cetaceans, but on the second day they marveled at the sight of a group of 16 orcas (Orcinus orca), the largest of the dolphins (no, they are not whales)—the biggest males can be 10 meters long and weigh 10 tons—behind Ilhabela, on the north coast of São Paulo. They are not usually seen so close to the coast. “We spent almost two hours with the orcas, watching and photographing them,” Santos recalls. “We know very little about them, how many there are, when they’ll show up.”

A comparison of dorsal fin photographs shows that two individuals in the Ilhabela group had been seen near the beaches of the city of Rio de Janeiro, 400 kilometers away, two months earlier. Alexandre Azevedo, an oceanographer from Rio de Janeiro State University, helped compare the photographs and confirmed that they were the same animals. After each trip, one of tasks of the researchers was to examine the dorsal fin photos using a special computer program, to find the ones that showed new individuals and enter them into the catalog on the laboratory’s website. The catalog now lists 104 animals from two whale species and three dolphin species, all represented by their unique fins.

There are reasons for concern as well. Because of port construction, the growing number of boats and increasing pollution levels along the coast, cetaceans may be moving away from the coast in search of calmer areas. Giovanna Figueiredo, from Santos’ team, has confirmed that since 2002 there have been fewer records of sightings of the 18-meter, 60-ton southern right whale (Eubalaena australis), once common on the beaches closest to the coast in the Southeast, even though the population has been growing since whaling was banned. On one excursion, the USP team sighted one of these whales with a calf off the island of Queimada Grande, 27 kilometers from the coast. Karina Groch and other biologists from the Southern Right Whale Project are mindful of the potential effects of the construction of the port of Imbituba, in Santa Catarina, and the increasing boat traffic in the region, which was once a regional center for hunting the southern right whale. In 2005, Groch estimated the number of southern right whales that regularly visit the Brazilian coast to be 500, of which 100 take shelter along the southern coast, especially during the reproductive period from July to November.

“We are driving away the whales and dolphins through a series of actions that have a cumulative effect,” says Siciliano, who has published a number of articles in recent years pointing to contamination by heavy metals and other toxic substances, which in dolphins can lead to bone deformations, as he himself has recorded, and skin diseases, which Santos described in 2009. “It’s a shame, because the populations are recovering, and cetaceans are seeking out inlets they used to occupy, but are finding them turned into ship parking lots and sewage dumps.”

Siciliano was one of the researchers who helped develop the action plan for conservation of the La Plata River dolphin, a species that lives near the coast and has a high mortality rate from getting caught in fishing nets (Santos is helping fishermen in Cananeia look for possible ways to reduce the mortality rates of these river dolphins). The action plan, approved and made public in 2010, called for the creation of two national parks (in Santa Catarina and Rio Grande do Sul) and the expansion of another on the northern coast of Rio de Janeiro State that currently features only restinga coastal dunes. The objective is to designate a suitable area for La Plata River dolphins, sharks, rays, turtles and other marine animals. Siciliano, commenting that the parks have not yet been created, recalled that there was resistance to a fishing ban and to transforming an area coveted for port construction into a national park. At one of the meetings on creation of the marine conservation units, he remembered, an official from a public environmental agency asked the researchers, “After all, what is a La Plata River dolphin good for?” In a play written by the playwright Bertolt Brecht, a cardinal asks a similar question as he declines to look through Galileo’s telescope: “Are stars really necessary?”

1. Cetacean occurrence, distribution and movements along the coast of São Paulo State (nº 11/51543-9); Grant mechanism Regular Line of Research Project Award/Biota; Principal investigator Marcos César de Oliveira Santos – IO/USP; Investment R$454,775.03 (FAPESP).
2. Accidental captures of small cetaceans during fishing activity along the southern Sao Paulo coast: seeking support for the development of conservation policies (nº 10/51323-6); Grant mechanism Partnership for Technological Innovation (PITE); Principal investigator Marcos César de Oliveira Santos – IO/USP. Investment R$242,490.33 (FAPESP).

Scientific articles
CABALLERO, S. et al. Initial description of the phylogeography, population structure and genetic diversity of Atlantic spotted dolphins from Brazil and the Caribbean, inferred from analyses of mitochondrial and nuclear DNA. Biochemical Systematics and Ecology. V. 48, p. 263-70. 2013.
SANTOS, M.C.O. et al. Cetacean records along São Paulo state coast, Southeastern BrazilBrazilian Journal of Oceanography. V. 58, No. 2, p. 123-42. 2010.