Cruises 2011 Cruises CalCOFI 1108NH
CalCOFI 1108NH Scientific Report
The summer 2011 CalCOFI cruise began smoothly with favorable seas for the first two transects that puts us over 300 miles out to sea. Water temperatures are seasonal with warmer than average temperatures near shore off San Diego and below average around Santa Monica Bay. Warmer water is pushing into the outer waters of the Southern California Bight likely caused by the Davidson Current. The California Current is visible in our data when looking at the closeness of the isotherms of the 100 meter temperature between CalCOFI Stations 70 and 80, roughly 200 miles from shore. Eggs from spawning fish have been sparse, and salps and pyrosomes have been numerous especially in waters coming up from the south. Also noteworthy, oxygen around 100 meters is low compared to mean data although temperatures at that depth are seasonal. Net tows, bongo, manta and Oozeki seem to be seasonally sparse of krill normally encountered in the waters behind the Channel Islands, possibly as a result of numerous species of whales observed on the cruise. Winding up the cruise off Avila Beach we have encountered abundant krill in the Oozeki trawl with matching acoustic data. The usual albatross, storm petrels, gulls tropic birds and terns was joined by a brown booby from parts south.
Last Updated on Wednesday, 17 August 2011 15:44
All toll, with only moderate winds and seas and steady work, it’s hopefully been an enjoyable way for Captain Murray Stein to spend his last cruise before retirement. It has been all the more pleasurable with Mark Smith and Oscar Buon serving up some fine dining on steaks, fish and some fine ahi sashimi and poki plus a few celebratory cakes. I can only hope to one day enjoy such a bounty to end my time at sea.
13Aug2011 DMW, Chief Scientist CalCOFI 1108NH Marine Mammal Report
Marine Mammal Observation Summary
Last Updated on Wednesday, 17 August 2011 15:42
CalCOFI 1108, R/V New Horizon, Chief Scientist Dave Walgast
By Katherine Whitaker and Dominique Camacho
Marine mammal observations were conducted simultaneously with passive acoustic monitoring during daylight hours throughout the CC1108 cruise. Within a 17day period we performed observations on the CalCOFI grid. The first portion of this cruise was met with great weather, allowing for easy sight ability. Unfortunately, the weather condition on the second portion of the cruise was consistently Beaufort 5, giving us more of a challenge during observations. Overall, we accrued over 148 cetacean sightings totaling 3930 individuals, comprised of 8 different species. Acoustic effort confirmed presence of and sperm whales (Physeter macrocephalus), in the study area; however no visual sightings were made.
Odontocetes were the most diverse and commonly observed suborder this cruise. 68 sightings were comprised of common dolphins (Delphinus delphis, Delphinus capensis, and Delphinus spp.), bottlenose dolphins (Tursiops truncates), Risso’s (Grampus griseus), and Dall’s porpoise (Phocoenoides dalli). Sightings were most abundant along the continental shelf and steadily decreased as we progressed offshore. Coinciding with past trends short-beaked common dolphins (Delphinus delphis) were seen offshore while the long-beaked common dolphins (Delphinus capensis) were found near shore.
An exceptional sighting of blue whales Balaenoptera musculus), occurred while transiting along the near shore Sccoos line from station 87/33 to station 87/35. This group was comprised of 19 individuals, which surfaced for intervals of lunge feeding and then terminally dove. These whales were in an amazing feeding aggregation with 2 fin whales (Balaenoptera physalus), 2 minke whales (Balaenoptera acutorostrata) cow calf pair, and over 100 common dolphins comprised of (Delphinus delphis, Delphinus capensis, and Delphinus spp.).
Fin whales (Balaenoptera physalus), were sighted in two more large aggregations over the edge of the continental shelf. They were spread out for miles, and observed continually for up to three hours that numbered over 20 fin whales with some blue whales associated. On line 77/70 going to station 77/60 the smaller aggregation of fin whales, comprising of 10 or more, was on transect line 90 between station 60 and station 53.
California sea lions (Zalophus californianus) were predominately encountered within 200 nm from shore, for which we performed cumulative day counts. We observed 84 individuals over the course of the cruise.
There were 9 confirmed fur seal sightings scattered through out the survey near shore and into the offshore waters.
We can’t leave out the special observation of a jumping blue striped marlin as we headed out to 93/120, our farthest offshore station. A basking shark was observed near shore of San Diego while transiting back to port on the final day of our cruise.
1108NH Cruise Prospectus
CalCOFI 1108NH Passive Acoustics Report
Marine Mammal Acoustic Operations Summary
Last Updated on Wednesday, 17 August 2011 15:42
CalCOFI 1108, R/V New Horizon, Chief Scientist: Dave Wolgast
July 27 – August 13, 2011
Anne Simonis
Marine Physical Laboratory, SIO
Acoustic Methods:
Acoustic monitoring for marine mammals was conducted concurrently with visual observations during daylight hours. A six-element hydrophone array was towed during daylight transits between stations, and expendable Navy sonobuoys were deployed upon arrival at stations. Two marine mammal observers were present on the bridge during all daylight transits. Acoustic signals from the hydrophone array and sonobuoys were continuously recorded and monitored by the acoustician.
The six-channel hydrophone array was deployed during all daylight transits where at least 1.5 hours of data could be recorded. The array was towed 300 meters behind the ship and about 17 meters below the surface. Acoustic signals from the hydrophone array were continuously recorded with a sampling rate of 192 kHz for channels 1, 2, 3 and 6 and 500 kHz for channels 4 and 5. The acoustician monitored channels 1, 2, 3 and 6 aurally as well as visually by a scrolling spectrogram via Ishmael.
For all stations that were at least 3nm from shore and approached during daylight hours, two sonobuoys were deployed 1nm prior to arriving on station: one omnidirectional (omni) 57B and one Directional Frequency Analysis and Ranging (DiFAR) 53F. Both use a VHF carrier frequency to transmit acoustic signals to the ship, where the signals are received by ICOM R100 radios and recorded with a sampling rate of 48 kHz. Omni sonobuoys were monitored aurally as well as visually via a scrolling spectrogram in Ishmael.
Results:
In total there were 33 array deployments for a total of 95.5 hours and 860 nm and 63 sonobuoy deployments at 31 CalCOFI stations for a total of 139 hours. Throughout all of the hydrophone array deployments, 63 cetacean groups were detected with associated acoustic signals recorded by the acoustician, 21 of which had corresponding sightings by the visual observers. During the sonobuoy deployments, 29 detections were logged, three of which had visual confirmation. Species recorded included short-beaked common dolphins (Delphinus delphis), long-beaked common dolphins (Delphinus capensis), risso’s dolphin (Grampus griseus), sperm whales (Physeter macrocephalus) as well as unidentified odontocetes and unidentified large whales. Anthropogenic sounds such as ship noise, mid-frequency sonar, underwater communications and explosions were also noted.
CalCOFI 1108NH CTD Raw Cast Plots
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CalCOFI Report Vol 51, 2010 pdfs are online. |
