By Jami Smith
The best way to count the world’s whales just might be from hundreds of miles above them, in space. High-resolution images from satellites are proving useful for calculating whale populations, according to a new study published in PLoS ONE last week.
Southern right whales were hunted extensively from the 17th into the early 20th century. The pre-whaling population was estimated at 55,000–70,000, but their numbers are believed to have dropped to as low as about 300 animals by the 1920s. The cessation of whaling has helped, and in 1997 the estimated total population was 7,500 animals. Surveys have found their overall numbers since then have continued to increase.
But recently there has been a rise in southern right whale deaths on the Atlantic coast of Argentina. According to the Wildlife Conservation Society:
The southern right whales that use Península Valdés, Argentina, as a nursery ground have suffered the largest mortality event ever recorded for the species in the world. At least 605 right whales have died along the Argentine coast since 2003, including 538 newborn calves. One hundred and thirteen calves died in 2012 alone.
Assessing the cause of this die-off has been a challenge to researchers. Having reliable population numbers from season to season would help. But traditional methods of whale population assessment –counts executed by trained researchers from land, air or ships– are costly, time-consuming and inefficient.
When Peter Fretwell and his colleagues from the British Antarctic Survey decided to test satellite imagery as a tool for surveying whales they chose the southern right whale for some of the same reasons the whale was once a hunting target: its large size and its tendency, in the breeding season, to bask near the surface in sheltered, coastal waters. A big marine mammal swimming in calm, shallow water should be easy to see from space.
The authors selected a high-resolution image from a WorldView2 satellite made over Golfo Nuevo Bay in the Península Valdés in September 2012, mid-breeding season. The image shows the middle of the bay, an area with a high density of southern right whales, on a cloud-free day with calm seas.
Using image-processing software and automatic detection of whale-like features in the water column, scientists identified 55 probable whales and 23 other features that could be whales on, or just below, the surface of the bay. The authors also observed 13 objects that were only detected under certain wavelengths of light that also may have been whales. They found that automatic detection of whale-like objects was most accurate at specific wavelengths. Through these tests, they concluded that their satellite imagery methods are more efficient than traditional methods of assessing populations of marine mammals. The authors suggest satellites might even be able to survey behavioral patterns of marine mammals in the future.
The process is not yet perfect: Rocks, seabirds and other species of whales could be confused as the target species by automatic analysis. And rough surface waters, whales rolling or bubble blowing can also affect accuracy. But overall, the authors are encouraged by their findings. Fretwell says, “The ability to count whales automatically, over large areas in a cost-effective way will be of great benefit to conservation efforts for this and potentially other whale species.”
Sea Shepherd Conservation Society’s Cove Guardian Lead and Campaign Director, Scott West has been denied entry into Japan. West sees it as an effort to prevent the actions of the Taiji Fishermen’s Union as they slaughter dolphins and small whales, from being exposed.
Upon trying to enter Japan to join Sea Shepherd’s Cove Guardians on the ground in Taiji, Scott West was detained by Immigration, held and interrogated for more than 4 hours. Following the questioning, Immigration denied him entry and released him to leave Japan and return home.
West was told that he is being denied entry on the basis that he would be photographing the Taiji fishermen against their wishes. It is not hard to see why the Taiji dolphin killers do not want to be photographed as they drive entire pods of dolphins and whales into the killing cove, where they tear their families apart to sell some for lives of slavery in captivity and brutally slaughter the others, he says. Traumatized dolphins and small whales swimming in the blood red waters of the Cove do not make an image that Japan wants the world to see.
Sea Shepherd’s Cove Guardians are regularly held and questioned by Japan Customs as to why they are seeking entry into the country. Some have been permitted to enter, while others are sent home.
“The dolphin killers and the government of Japan continue to claim that the hunt in Taiji is a long-held cultural tradition. The bottom line is that this barbaric “tradition” only started in 1969 when the captive dolphin industry started to grow, and the hunt continues for the same reason it began: greed. If this is a proud tradition, why is Japan trying so desperately to stop our Cove Guardians from showing it to the world?” said West.
The drive hunt and slaughter of thousands of dolphins, porpoises and small whales occurs throughout Japan each year. The most well-known among these annual hunts occurs in Taiji from September 1st and usually continues to March 1st of the following year. Sea Shepherd Conservation Society first brought Taiji’s killing Cove to the world’s attention by capturing and releasing now-iconic undercover footage and photos of the brutal captures and slaughters in 2003, revealing the blood-red waters of the Cove. Later the Academy Award-winning film “The Cove” again shone a spotlight on the hunts, bringing international attention to the dolphin killings. These dolphin hunts also used to occur in other parts of Japan, like Futo and Iki Island, but they have since ended. The continual mass slaughter left no more dolphins to be found. If the annual massacre of dolphins and whales in Taiji continues, they will vanish from the waters surrounding Taiji’s killing Cove, as well.
In a strongly worded letter to all of Scotland‘s MSPs, Orri Vigfusson, chairman and founder of the North Atlantic Salmon Fund (NASF), accuses Holyrood of contributing to a catastrophic decline in salmon stocks on Scottish rivers.
Vigfusson, who is lauded in Iceland for his work in salmon conservation, writes: “Your country encourages and supports the proliferation and expansion of unsustainable fin fish farms. You overfish your fish stocks and you encourage interceptory mixed-stock salmon fisheries that target the fish we have protected while they feed in our waters.
“We have given these salmon safe passage in the belief that they will be allowed to spawn and help restore Scottish rivers. Instead, far from being rebuilt, your salmon abundance has declined by 80-90% in recent decades. This is principally due to the failure of your authorities to manage them properly.”