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CalCOFI Scientific Report 23 Jul 2004 -
CalCOFI Scientific Report - With the first half of the Summer 2004 CalCOFI cruise completed, we all have to thank our lucky stars for the opportunity to be out here studying the ocean.
We are ahead of schedule with calm conditions that are optimal for CTD casts and net tows alike, making transits from station to station very timely. I knock on wood as I state, all equipment and personnel are functioning at peak performance, to be expected under these cooperative conditions.
Team work has been the order of the day aiding our efforts, not only with long standing friends from National Marine Fisheries, but also with a relatively new Marine Mammal observation program
being integrated into the existing work. Thanks to John Hildebrand and his representatives at sea which include graduate student Melissa Soldevilla and two observers from Cascadia Research. Using acoustic devices we have heard from a sperm whale feeding, Pacific White Sided dolphins and some Common dolphins.
In the past, CALCOFI cruises have had a single dedicated bird/marine mammal observer to document all species sighted along the transect lines between stations. Beginning with this cruise there are three observers on the flying bridge, one for birds, and two to identify and count marine mammals. Although numbers of species seen this week are in the single digits, and the sea state has been mostly Beaufort 4 or 5, the marine mammals that we did observe were quite interesting. Of the 46 sightings recorded, 23 were Common dolphins. Aside for the south/westernmost transect line when all marine mammal life deserted us, we could count on our daily dolphins visitations. Distant Blue and Fin Whales blew great chimneys of vapor into air between 118° and 120° of longitude, while farther west we were surprised by a breaching Cuvier's Beaked whale! On July 17, the stations were situated along a steep slope that goes from 3000m depth to 800m. Generally, these areas are very good for viewing a number of species that feed in the colder upwelling waters along the slope. It was in these waters that we saw a group of 10 or more Baird's Beaked whales! The week ended with a spectacular sighting of 300 + Common dolphins feeding beneath Elegant Terns and Western Gulls.
Bird numbers and distributions have generally been as expected. Relative near shore locations have had the highest concentrations of bird numbers, species diversity and feeding observations. Common near shore species were Western Gull, Heermann's Gull, Pink-footed Shearwater, and Elegant Tern with smaller numbers of Brown Pelican, Pelagic and Double-crested Cormorant, Sooty and Black-vented Shearwater, and Red-necked Phalarope. Several small (<100 bird) feeding flocks were observed the
morning of July 19, apparently associated with baitfish, and primarily involved Western Gulls, Pink-footed Shearwaters, and Elegant Terns. Large numbers (hard to estimate for a large area, but 200+) of Pink footed Shearwaters were also observed at these feeding flocks and surrounding ocean this morning (more in one place than I had ever seen before.) 4 Xantus’ Murrelets (July 17) and 4- 5 South Polar Skuas (18 19th) were fairly exciting, and in fairly deep waters, as expected, beyond the
Channel Islands. Further off shore in deeper waters species diversity, overall numbers, and active feeding observations were much lower. The birds found there are deep water obligates and travel huge areas to find food, and therefore spend most of their time flying. Leach’s Storm-petrels were scattered throughout the deep waters (we began observing them the evening of July 13th), with most concentrated in the middle area of the transects, i.e. the area we covered on July 14 (heading
offshore) and 17th (heading inshore). Those days almost all observations were of Leach's Storm Petrels. Cook's Petrels were fairly common over the farthest areas (we began seeing them the morning of the 15th, and were virtually the only species observed by the 16th.) Two groups of up to16 Cook's Petrels were seen floating on the water, suggesting active feeding. Small numbers of Black-footed Albatross and Red-billed Tropicbirds were observed over deeper waters. With promises of more
animals to the north we look forward to next week, and what the sea might bring.
Rounding out are efforts this cruise, graduate student Andrew King is continuing his iron centric sampling program in addition to assisting with the standard CalCOFI work.
After completing only two transects, examination of the preliminary data seems typical of the summer season.
A cool band of water at 150 miles offshore that has available nutrients in the surface likely represents the California Current. Inshore of that water mass there is a push of warmer, higher salinity water characteristic of the Davidson counter current. A warm intrusion of central gyre water is becoming evident as we collect station data during our progression north.
Recreational fishing efforts are bolstered by our medical officer, Lt. Commander Robert Frickey's, enthusiasm even if
they have so far gone completely unrewarded. Our hope springs eternal and so will our efforts. As long as steward, Rick Hargis, continues to fill our bellies and our spirits alike. Food being a major morale booster at sea, Rick doesn't depend only on his ample skills in the galley but also on his comedic emphasis on our origins as children of the world.
Able ship handling and experienced ultra-friendly winch operators make our work easier and has made it a pleasure to sail with our friends and work mates alike. (Dave Wolgast)
- CalCOFI Cruise Report 30 Jul 2004
Week two of the Summer CalCOFI cruise was a sweeping success thanks in part to the relatively calm seas. All regular stations were completed, plus some additional shallow stations have been tested (20 meter). Preliminary data
plots indicate a strong California Current coursing down the coast and ranging far offshore between 120 and 200 miles. A warm core eddy pushes the current toward shore in the middle of our sample grid, and near surface temperatures within the current trend on the higher than average side, especially in areas where it is usually very strong. Whereas salinity anomalies in surface waters are not far from average. Deeper (100 meter) data seem to indicate the dynamic nature of
the current with large (1 to 2 degree differences from 50 year average) anomalies in regions well offshore, both in the cold current and in the warm eddy waters. This is also reflected in 100m salinity data, where positive salinity anomalies follow negative temperature anomalies throughout the pattern. All told, the data should lend itself to interesting analysis and modeling in the near future and bolsters the need for continued collection of our 50 year data set.
Preliminary data
from phytoplankton grow out experiments show iron limitation, not completely unexpected considering the distance offshore of the upwelling area within the current. These regions should be well outside major anthropogenic, aolian input.
As to our continued mammal observing efforts, hope of “more animals to the north” at the end of last week came to fruition, with almost double the number of marine mammal sightings (93 in the 8 days since the last report). Although sea conditions
remained marginal for optimal mammal observations most of the week, we were treated to two days of relatively calm seas in deep offshore waters. Many of our sightings, including 9 sightings of sperm whales, came from those two days of effort. The most common “species” sighted in the last 8 days were deemed “unidentifiable”, animals seen only at a distance. For the entire 8 days, short-beaked common dolphins were the most numerous, with nine groups often in the hundreds of
individuals. Highlights of the week included a close look at a Cuvier’s beaked whale, close sightings of blue whales, fin whales, and a probable sei whale. The species list for whales and dolphins on the trip topped 11 with our first sighting of Dall’s porpoise, just before our last daylight station as we headed towards the end of our survey lines. All in all a very productive two weeks.
Seabird observations reveal Leach’s Storm-petrels continue to be the most commonly encountered
species, with individuals and small groups seen scattered over deep off shore waters. Cook’s Petrels are fairly common at the furthest areas beyond 150-200 miles from shore, true mariners. Small numbers of Black-footed Albatross and Red-billed tropicbirds were also seen over the deeper waters.
July 23, 24 and 27th we covered some areas of relatively cold water, and associated with it were large numbers of Pink-footed and Sooty Shearwaters, Western Gulls, and Cassin’s Auklets, among
others. This corresponded to much higher plankton net tows as well. The morning of July 27 shortly after completing the last transect seemed like a grand finally of wildlife sightings. Some of the highest concentrations of birds and whales seen during this cruise were observed. Dozens of Common Murres fathers toted around small chicks and Sooty Shearwaters zipped across the surface of the water left and right. A memory not soon to be forgotten!
Congratulations to the science party as a
whole for acting as a coordinated team in getting the work done well and in a timely manner. Finally, our usual thanks and praise go to the acting captain, executive officer, Brian Parker and the rest of the crew of the R/V David Starr Jordan for making our voyage such a success. It has been a pleasure sailing with them again, and I wish them safe passage on the South Cruise in the months to come. May the fishing be much more favorable for that cruise than it was for
us. These are not sour grapes, but acceptance of fate as seen fit by luck or the powers to be.
We look forward to our next cruise and the opportunity to voyage out upon the beautiful blue Pacific Ocean again, especially on the flag ship of the Scripps fleet, the R/V Roger Revelle (Nov. 2-21).
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