This picture shows two Sergeant Majors laying eggs in a nest. Sergeant Majors are small reef fish. Each was about 6 inches long.
This pair of fish was building a nest at night. It was about 8 P.M., and we were diving in water about 40 feet deep near the island of Bimini. The fish would take turns swimming to the nest. First, the female would lay eggs in the nest, and then the male would fertilize them. The nest contained many thousands of eggs when they were finished.
Young fish are easy prey for larger fish. The coral reef is a very competitive place. There are hungry fish everywhere. That's why it takes thousands of Sergeant Major eggs to guarantee that a few of the fish will survive to become adults.
After building this nest, the male Sergeant Major will stay near the nest for several days to guard the eggs until they hatch. The female will leave during this time. The male will chase away all other fishes to keep the eggs from being eaten. The male Sergeant Major can be very aggressive during this time, and will even attack people in the water if they accidentally get too close to the nest. Although the Sergeant Major probably couldn't hurt anyone, it will fearlessly try to drive away anybody that it thinks is too close to its nest.
Sergeant Majors are common worldwide in tropical waters.
This story first appeared in the e-ReefNews e-mail newsletter, Volume 1 number 13.
To subscribe to this free newsletter, check out the e-ReefNews subscription page.
You can order the entire e-ReefNews Volume 1 on CD-ROM, from the ReefNews Online Catalog.
Dr. Jonathan Dowell took this picture using a Nikonos V with 28mm lens and SB105 strobe.