The Hawaiian Sergeant Major Fish

By Romana Annette 03/03/2009

While on Maui, we drove down to Lahaina to take a tour on the Reef Dancer, which is referred as a submersed view boat, rather than a real submarine.  This was in preference to going on an actual submarine, such as the Atlantis, since my wife, Carolyn, would have had trouble descending the steep set of steps.

As we pulled away from Lahaina Harbor, we got an excellent view of the city itself, with the ancient volcano in the background.

Here is a picture of the viewing area of the Reef Dancer.  Through the many windows, we could watch the underwater world move by as we headed to the reef with the best views.

While on the tour, we learned about the Hawaiian Sergeant Major fish, so-named because of their striped markings.  We were told that these fish considered the Reef Dancer to be their home.  Not only did they accompany the boat on its daily tours, but they also went with the boat to the Big Island for servicing. My picture from the boat did not turn out very good.  The black fish in the background is a Black Durgeon Triggerfish, one of the predators of young Sergeant Major fish.

Here are clearer pictures from the Maui Ocean Center Aquarium, using our underwater cameras dunked into shallow pools.

Sergeant Major fish are reef-dwelling fish, a member of the Damsel Fish family, the same as Clown fish, as shown in Disney’s Finding Nemo.  I am not sure exactly how these fish have converted a boat to a reef.  Perhaps they lay their eggs somewhere on the hull of the boat, since reproduction is a necessary part of these fishes’ life cycle.

Sergeant Major fish have complex lives.  The male broods the eggs, and there is generally only one male in an area.  These are harem fish, so each breeding male has a harem of females.  If a dominant male should die, the most dominant female will change sex and become the new keeper of the harem.

If there should be excess males, some of them will change sex and become females in a dominant male’s harem.  This is efficient and allows as many fish as possible to fit into the social scheme.

There is no corollary for human beings, except in transgender fiction.  In some very sexist stories, vanquished warriors are changed to women and sent to live in their conqueror’s harem.  For Sergeant Major fish, I just see a model of biological convenience, not one of dominance or subjugation.