CalCOFI cruise 0901NH, the winter 2009 cruise encountered relatively calm conditions due to the persistent high pressure and off shore winds. Once our calibration of Tony Koslow's new EK-60 sonar was completed inside San Diego Bay, hydrographic data collection could begin. Preliminary hydrographic data revealed the California Current to be strongest well off shore in the range of stations 90 and 100 and beyond. Salinity, 10m & 100m salinity anomalies plus 100m temperature revealed the current flowing in this region and then jetting in to the coast towards Dana Point. Both 10 and 100 meter temperature anomalies showed a preponderance of negative values, this was consistent with our casual observation of cooler than average sea surface temperatures and air temperatures. Windy, stormy conditions were known to have preceded this cruise but the mild conditions may have given way to higher phytoplankton production as seen in higher-than-usual offshore near-surface chlorophyll values. In addition to these observations, nutrients were assayed to be high in some of the same offshore regions, further bolstering the observed productivity of the region. Upon processing data for this cruise, a peculiar down-welling event was evident at Station 83.3 100.0. Higher temperatures and lower nitrate were evident down to 500m. Oxygen was elevated compared to depths at other stations in the region. Density was low enough to be anomalous, but not impossible. This feature will likely be evident in the deep flow field of the California Current (as seen post cruise).
Marine mammal observations by Andrea Havron & Dominique Comacho: This cruise was marked by higher than normal species diversity and whale abundance. This increase of sightings could be related to the superior weather conditions allowing for better ability to sight and identify marine mammals. This cruise was marked by a high number of humpback whales. Past winter CalCOFI surveys tally numbers of unidentified large whales while concurrent acoustics detected humpbacks in the vicinity. This survey raises the question of whether humpbacks frequent the CalCOFI lines over winter and warrants further investigation. As to be expected, areas surveyed around the Channel Islands offered the largest variety of whale and dolphin species. Near San Clemente Island, between stations 90/45 and 90/37, we encountered about 15-18 humpback whales, minke whales, and common dolphins. Near Santa Rosa and Santa Cruz Islands between station 83/51 and 83/42, we sighted fin whales, humpbacks, grey whales, risso’s dolphins, bottlenose dolphins, and both forms of common dolphin, long and short beaked. Dall’s porpoises were encountered during the transit north to line 80 and continued through line 77. This section also offered us additional sightings of grey whales, humpbacks, minkes, and common dolphins. Other species of interest include killer whales, seen just before station 90/60 and station 77/51 and one sperm whale sighted past station 90/70.
Marine mammal acoustic comments by Lisa Munger: Acoustic operations overall went smoothly without incident. We towed a six-element hydrophone array (capable of detecting odontocetes but not baleen whales) during transits and deployed omni-irectional Navy sonobuoys (capable of detecting baleen whales and low-frequency odontocete sounds) on stations. Delphinid clicks and whistles were detected offshore at ends of lines 93, 90, 87, and 83, and inshore on lines 90, 87 and 77. Species sighted during acoustic detections included common dolphins, bottlenose dolphins, Risso's dolphin, and killer whales. Dall's porpoise were also sighted along lines 87 and northward, but we were not capable of monitoring in real-time for Dall's porpoise clicks, so Dall's acoustic detections are pending. During sonobuoy deployments, humpback whales were detected at the majority of offshore stations (16 of 30 sonobuoys) on all lines (figure 1). Fin whale calls were detected on two sonobuoys, 93 inshore and line 87 about midway offshore. Sperm whale clicks were detected on four sonobuoys, three of which were midway out on lines 90 and 87.
All station work was performed well within the time allotted, including SCCOOS and LTER/CCE. A fortuitous encounter with Humboldt squid, Dosidicus gigas, at station 77.80, yielded 15 specimens on deck and numerous lost. Supplemental fish collections were performed, further testing our acoustic abilities and intentionally delaying our return for a quick touch-and-go to allow for a final acoustic calibration in the bay. The loss of the bongo net with the Laser Optical Plankton Counter due to rusty hydro wire and possibly other unknown deep sea encounters was a dark spot on an otherwise perfect cruise.
We thank Captain Chris Curl and the cooks for keeping it light and helping us to get our work done unabashed and smiling.