(Blue Ocean Network – September 6, 2013) — Some pale whales appear to tan in order to protect themselves from sunburn says a new study. An international team of scientists took mitochondrial DNA samples from blue whales, fin whales and sperm whales to check for genetic damage from ultaviolet rays. The palest of the three study whales, with mottled blue-grey skin, blue whales appear to adjust their pigment as they move from higher UV environments to lower. In contrast, fin whales, the blue whale’s darker-skinned, stay-at-home cousins, showed a reduced ability to change the level of melanin in their skin.
The scientists found that higher melanin levels in the whale’s skin correlated with lower levels of skin lesions and DNA damage, suggesting melanin protects the ocean mammals from sun damage.
“We found molecular evidence that blue whales increase production of melanin, so this would indicate that they tan,” Karina Acevedo Whitehouse, a zoologist from the University of Queretaro in Mexico, and one of the authors of the study published that came out this past week in the journal, Scientific Reports. “Increasing their pigmentation (tanning) appears to be the way blue whales protect themselves from UV damage.”
They also found that the ability to modify skin pigment – or tan – may be linked to migration patterns.nAbout Blue WhalesnBlue whales are believed to be the largest animal to have ever lived on Earth. They’re found in every ocean in the worlds, spending summers in polar waters before the lengthy migration toward the equator for winter. These magnificent marine mammals rule the oceans at up to 30 meters long and upwards of 200 tons. Their average life span in the wild is between 80 to 90 years.
Blue whales feed almost exclusively on krill, during certain times of the year, a single adult blue whale consumes about 4 tons of krill a day. Blue whales typically feed at depths of more than 100 meters during the day and only surface-feed at night. Dive times are typically 10 minutes when feeding. The blue whale also accidentally eats small fish, crustaceans and squid caught up with krill. Blue whales have few predators but are known to fall victim to attacks by sharks and killer whales. Moreover, many are injured or die each year from impacts with large ships. Blue whales are currently classified as endangered on the IUCN Red List. There are only 12,000 or so left in the world, from a population once numbering 250,000. More detailed information about Blue Whales can be found here.
Diving with Blue Whales
Diving with Blue whales is very rare, they are hard to find, spending lots of their time at depth and are most commonly seen from boats or on whale watching cruises or helicopter flights. Amos Nachoum of Big Animal Expeditions has encountered many blue whales during his career as a marine life photographer. He conducts trips out of San Diego to Baja California where a small group of guests can snorkel and free dive with these amazing mammals. Nachoum’s team has created an elaborate blue whale tracking system, recruiting fishermen along the Pacific coast of Baja California to radio in the first sign of the blue whale’s northern migration. Nachoum brings four professional kayakers, take his four guests, each in their own kayak, closer to the gentle giants. The kayakers intercept the whale’s route as directed by the scout plane, and then, quickly and very quietly, the snorkelers enter their space and let the whales get comfortable with them. Says Nachoum, “It’s then that it hits you: you’re diving alongside a blue whale. It’s like swimming next to an 18-wheeler, cruising along at 12 mph.”
The next US blue whale trip is scheduled for July 13 – 19, 2014. For more information about the Baja California Blue Whale trip visit Big Animal Expeditions. Big Animal Expeditions is also running two upcoming trips (march 8 – 16; march 15 – 23, 2014) to Sri Lanka to dive with the pygmy blue whale, a 60′ whale version. For more information about the Sri Lanka Pygmy Blue Whale trip visit Big Animal Expeditions or email email@example.com.
Photo Credit: Amos Nachoumn