The NOAA ship McArthur II left San Francisco on Wednesday September 17th for the third leg of the ORCAWALE cruise, a marine mammal assessment survey of the U.S. West Coast waters. The objective of ORCAWALE (Oregon, California, Washington Line-transect and Ecosystem survey) is to estimate the abundance and to understand the distribution of dolphins and whales off of the west coast. The cruise also characterizes the open ocean ecosystem through physical and biological oceanographic sampling, studies of mid-trophic level organisms, and seabird research.
Our 22-day leg will take us from San Francisco to San Diego on designated transect lines which stretch out to 300 nautical miles offshore. The first day our survey started off of Drakes Bay and headed out past the Farallon Islands. The waters in the Gulf of the Farallons were teeming with life: humpback whales, Dall’s porpoise, and groups of porpoising sea lions were all around us. Large flocks of shearwaters were around the islands, including one Flesh-footed Shearwater, a rare visitor to Sanctuary waters. We then headed north towards Mendocino to try and fill in gaps from the previous leg, which was plagued by bad weather.
To survey marine mammals a team of observers is on the flying bridge, the highest deck of the ship. From dawn until sunset the six observers on board rotate through three positions. Two observers constantly scan the waters through the “big-eyes”, mounted 25×150 binoculars. The third observer records data as well as scans the water close to the ship through hand-held binoculars. When cetaceans are sighted the ship will turn on the animals to get group size estimates and try for photo ID shots and biopsy samples. One of my duties on board is to act as the Independent Observer, which tries to catch animals that the survey team has missed…no luck on this front yet.
On Thursday we headed offshore 90 miles and encountered a large group (20+) of Baird’s beaked whales. They are 30-40 feet long and have a bulbous head and dolphin-like beak. I had never seen this cryptic species before – although they are the largest of the beaked whales they are infrequently seen because they are usually only found in deep waters (>1000 meters/3,000 feet) and have low, bushy blows that are hard to spot at sea.
Friday and Saturday were spent off of Humboldt County. Although the forecast kept predicting bad weather we lucked out with flat seas and sunny skies. 60 miles offshore we spotted 2 blue whales. They were surfacing for short intervals and the ship could not get close enough for photos and biopsy samples. The decision was made to launch the small boat to approach the animals closely so that we could get photo ID shots to individually identify the animals as well as to collect blubber samples for genetic analysis. For the biopsy samples they shoot darts out of crossbows at the base of the dorsal fin.
Only a few minutes after we launched the small boat the whales suddenly surfaced right next to us, only about 15 feet away. It is hard to describe being right next to the largest animal on the planet in a tiny zodiac; I not only gasped but also think I shouted some superlatives. My heart was pounding as they were blowing and rolling right by us, the backs on these animals just go on and on and on before you see the little dorsal fin.
They dove again and we started waiting (they had been diving at 16 minute intervals). 30 minutes went by and nothing. All observers were searching from the big ship as well but they completely disappeared before we could get biopsy samples. I could not believe we lost them, but they had vanished into the abyss.
Sunday and Monday we headed 200 miles offshore of Fort Bragg. We sailed through patches of empty ocean that was occasionally broken up by flocks of Long-tailed Jaegers flying by. We traveled over the Mendocino Ridge, a deep underwater canyon. Fin whales started appearing all around us, as well as schools of common dolphins. The dolphins came over to the ship to bow ride. They were so fun to watch, they kept leaping out of the water in small groups. The biopsy team was able to get a couple shots as the animals came out of the water. Surprisingly the small nick did not seem to bother them, after being shot they could not help but come back over to play with us.
