Life Aboard Ship, Dispatches From South of the "Roaring Forties"

Life Aboard Ship

#19 July 14, 2004

#18 July 11, 2004

#17 July 6, 2004

#16 July 5, 2004

#15 June 30, 2004

#14 June 27, 2004

#13 June 23, 2004
Bouvet Island

#12 June 20, 2004

#10 June 16-17, 2004
South Sandwich Islands

#9 June 13, 2004

#8 June 9-10, 2004

#7 June 4-6, 2004

#4 May 26, 2004

#3 May 23, 2004

#2 May 19, 2004

#1 May 16, 2004
Punta Arenas, Chile

May 14, 2004
Landfall: Visiting Islands in the Atlantic Ocean

June 16, 2004
South Sandwich Islands

May 30, 2004
Falkland Islands

May 26, 2004
Science on the NATHANIEL B. PALMER

June 24-26, 2004

June 15, 2004

May 30, 2004

Questions & Answers

Tuesday, July 6, 2004

As you recall if you read Bulletin 16, we were due to arrive at Tristan da Cunha shortly. We did arrive, but we have a small problem: we are unable to land or collect the fish we came here to get! Tristan has no protected harbor; the anchorage is offshore of the only town, Edinburgh, and when it is too rough, it's not possible to land. This morning we were advised that the wind (almost 40 kts at the time) made it impossible. 

So, we steamed down the west side of the island until we reached Cave Point, behind which there is a wind shadow where we thought we could work. We put over our two inflatables and set fish traps and a long line in shallow water (about 20-30 feet) to try to catch B. diacanthus. We caught a few fish in the traps, but the long line came up with no fish and no bait. Unfortunately, the trapped fish were not what we wanted. We caught a rockfish, the false jacopever (Sebastes capensis) and a Tristan wrasse (Nelabrichthys ornatus) but no nototheniids. That wasn't too surprising, considering that it's a small fish (shorter than 10 inches maximum length) and seems to live in tide pools and just below the tide line in crevices. Where we were able to fish seemed to be boulders and cobbles, probably not the species' preferred environment. We also tried fishing with rod and reel, and that was quite successful for the species that dominates (by weight) the fish fauna of the shelf (near shore) areas in the Tristan group of three islands, the fivefinger (Acantholatris monodactylus). It is also the most commonly used for food and bait. We could hardly get a line to the bottom before hooking one. And, I can assure you that they really do taste good!


Just one of many five finger, Acantholatris monodactylus, caught off Tristan da Cunha.
The Tristan wrasse is particularly interesting because it undergoes a sex change during its life. Individuals start as females, but some change to males at 16-17 cm length. These become territorial during the spawning season, defending temporary territories of about 2 m diameter and enticing females to spawn if they enter the territory. What determines whether an individual changes sex is not understood.

Wednesday, July 7, 2004: This morning the weather is much the same, with the added possibility of an approaching front that seems very likely to make the surf even worse. We steamed up to Edinburgh and could see that the surf was quite spectacular all around the anchorage, where swells coming from the northwest collide directly with the lava cliffs to the north and south of the town. I would guess that some of the white water was reaching between 50 and 100 feet above the sea level. We sacrificed the remaining nototheniids several days ago before the seawater temperature rose to levels that would kill the fish. We need the B. diacanthus badly; for some of our researchers it is one of the primary reasons why they came. We are considering arranging for Tristanians to collect for us (for pay); these fish could probably be transferred by sending in an inflatable one time only. It would be a very wet trip, but we think it can be done. At least in that way we would have the specimens we came to get.


Anchorstock Point on Tristan. Barely visible on the lower slope are farm buildings, which give scale to the base of the island's volcanic center.
In the meantime, we have looked at the bottom around the other two islands here, Inaccessible and Nightingale, to see whether we might be able to collect near shore there but to no avail. We were rewarded by being able to see both of them this afternoon (this morning it was rainy and foggy) and I can state categorically that neither of them looks "friendly". Inaccessible merits its name: it is surrounded by cliffs of about 1000 feet in height; and how Nightingale got its name, we haven't a clue, because it doesn't look like "that kind of place"!

The wind has dropped this afternoon and we are hoping to be able to get ashore tomorrow. We have been in contact with the Fisheries officer on the island, and he thinks that if nothing changes, we will be able to collect; he has offered to meet us and drive us to the best locations. Stay tuned for the next installment to discover "did they ever get to the island?" and "did they ever get the fish they wanted?"!