NOAA Teacher at Sea
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004
Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 4, 2004
Latitude: 19 19
Longitude 156 05
Sunny with scattered clouds
Air temp 26C
Wind 130 degrees at 9 knots
Relative humidity 59%
Sea temp 26.5
Ocean depth 2770 meters
Scientific and Technical Log
This morning we hauled in the longline. This is the first time this team has used the larger hooks and herring (as opposed to squid) for bait as a means of avoiding taking of turtles. In that sense, we had tremendous success — no turtles. But on the downside, we caught only two fish — a mahi mahi (Coryphaena hippurus),still alive, and a wahoo (Acanthocybium solandri) which had died on the line. Eyes, liver, blood, and muscle tissue were taken from both. For the experiments on vision that Kerstin is doing only live eyes are useful.
Some surface plankton tows were conducted over a couple hours this afternoon. Several eggs were gathered and preserved. More tows will be conducted after the longline is set.
When nothing else was going on, two lines were trolled off the stern. This method yielded 4 fish including bigeye tuna (Thunnus obesus), skipjack tuna (Katsuwanus pelamis) and yellowfin tuna (T. albacares). These were sampled as above and in addition we kept stomachs for later study of contents. So 400 hooks sitting in the longline for 12 hours so far isn’t looking nearly as effective as a good old fishing line and a lure.
Tonight at 8PM we again set the longline, this one about 20 miles north of last night’s set. Because the winds are still very strong outside the shelter of the big island we are a bit restricted as to where we can go to fish right now. Winds are to becomes calmer over the next 48 hours.
Here is the longline set up in more detail than before. A spool holding about 40 miles of line sits parallel to length of ship on port side approx. mid-ship. Line feeds off to a pully along side of ship which directs line 90 degrees to stern. Via a couple more pullies the line goes to starboard side of stern. A team on the stern takes care of it from here. At center is person with basket of hooks attached to metal or monofilament leads with a clip on the other end. He withdraws the hook and clip, passing the hook to his right and the clip to his left while pulling the leader from the basket. The hook is baited, while the clip is passed to the next man to the left. On a signal about every 12 seconds, the leader is clipped to the line as it pours off the stern and the baited hook is tossed. A light stick goes on every fourth leader or so to attract fish. Better luck to us tonight!
My role this morning as line was retrieved was to record information (catch location, length, weight, sex) about each fish brought aboard and to assist in gathering muscle tissue samples for Brittany who is not present on this cruise as well as for others. Again I was brake man and bait boy on the longline tonight.
The afternoon hours seem to be those of least to do unless the troll lines are hot. Today I felt settled enough in the stomach to dare to enter a very confined space and enjoy my first shower at sea. Then I sought out a shady spot on the upper deck where I parked myself for a bit of reading. The wind was light and sea calm; I had a nice view of the west side of Hawaii. The lush, green slopes were interrupted in several places by lava flows. I had the opportunity to talk with the captain about many aspects of the ship, weather, ocean currents much of which I will try to incorporate into upcoming reports. But I was particularly interested in our rough weather of Sunday and he explained it as follows. As we crossed open water we were encountering winds of 20-25 knots, but as we entered the channel between Maui and Hawaii wind speeds were 35-40 knots. The reason for the increase is that both islands have very high mountains so the air is being funneled through a rather narrow slot and speeding up. This produced 10-12 foot waves with very short periods, and the ability to create a lot of discomfort in those at sea.
Tonight as we work, the light of a full (?) moon dances on the water.
One more (easy) location question for the astronomy buffs: Our latitude today is about 19 degrees north. What is the altitude of the North star (Polaris) as we view it from here? What is its altitude at your latitude?
OK, so we know where we are, but how did the Hawaiian islands get here? All of these islands are of volcanic origin. The Hotspot theory explains how the islands formed here. Briefly describe this theory.
Which of the islands (easternmost or westernmost) are the oldest in the Hawaiian Island chain? How long ago are the oldest islands estimated to have formed?
The Galapagos Islands also formed according to the hotspot theory. Which islands in that chain are oldest (eastern or western islands)? How old are the oldest of those islands?
For those who are wondering, yes, I do expect to be able to post some pictures, but we are not quite set up yet at this end to do so. That’s all for now,