July 14, 2003

We are halfway through the first leg of the cruise. Our goal for this
portion of the cruise was to complete a map of an area on the north side
of San Migel Island.click here to see map.The area is centered on the Harris Point Marine Protected Area and includes waters to the east and west of the reserve.
We had begun mapping this area last year using the McARTHUR, starting closer to shore. This ship, the McARTHUR II, is fifty feet longer and would not have been able to manuver as close to shore, so it is fortunate that we already completed the inside transect lines. On Wednesday, July 9th, we started offshore of last
year's efforts and are working our way offshore to the 100 meter contour
(the maximum depth we operate this sidescan fish).

With four days of sidescan behind us, we have completed 15 of our
transect lines. Each line is between 10 and 17 kilometers long and maps
300 meter swaths. The lines are spaced 225 meters apart therefore there
is 75 meters of overlap between lines. To date, we have mapped
approximately 64 square kilometers of habitat north of San Miguel
Island, representing over half of the area we intend to map. This is a
significant effort, which has been accomplished with the help of
excellent weather conditions. This is typically a difficult place to
work, with high winds and seas being common. During our four days in
the area, the highest winds we've encountered were 32 knots with 8-10
foot seas. Fortunately the McARTHUR II is better able to handle seas
than it's predecessor the McARTHUR. It is likely we would not have been
able to continue working on the McARTHUR given current conditions.

The sidescan data we have collected thusfar is excellent - with the
exception of one transect line. Our data had "noise" which we
attributed to the pitching of the ship in high seas. However, after we
completed the transect and pulled the sidescan fish aboard, we
discovered the problem in the data was due to approximately three
hundred pounds of kelp that had gotten tangled in the fish.
We hope to contine mapping this area for the next few days. Weather
permitting we could finish this area in less than two days.

7-19-03

CINMS/McARTHUR II Cruise Update - Sidescan Operations:
After completing our intended survey area at Harris Point Reserve, San
Miguel Island, we moved east to Santa Rosa Island to continue surveys
begun in previous years on the south east side of the island. We would
have preferred to work on the north side of the island, to begin mapping
the reserve there, however the seas would not permit our working on the
windward side of the island. Therefore we spent Wednesday, Thursday and
early Friday working a swath on the leeward side of Santa Rosa. During
that time we were able to map 27 square kilometers (we completed seven,
17 km long lines, each line mapping a 225 meter swath). This was a
continuation of an area mapped closer to shore using the McARTHUR.
The cruise was a complete success with regard to sidescan operations,
with zero time lost to weather or equipment problems.

Sarah Fangman
Research Coordinator
Channel Islands National Marine Sanctuary