How do we reproduce?

The Napoleon Wrasse, or Humphead Wrasse, have quite interesting reproductive patterns. These reef-located giants gather together in large numbers to spawn, similar to groupers in location choice (Sluka 2000). Wrasses earn the name “pelagic spawner” because they lay their eggs in the open water. More specifically, the process of fertilization begins when the male points the anal fin, or the fin on his stomach, down and folds the tail and dorsal fins, on its back,
against the body while hovering just above the ocean floor (
Bester 2013). The females then rise up as the male swims past, releasing gametes for fertilization near the surface of the water (Bester 2013). Therefore, the lifecycle continues, beginning with the combination of the gametes followed by mitosis in the gametic lifecycle.

After the fertilization of the eggs, according to the Shedd Aquarium, the specifically chosen current takes these eggs to float in the epipelagic zone, or near the surface of the open ocean (Shedd Aquarium 2006). After the offspring are hatched in the epipelagic zone, the larvae bid their time and float until they become large enough to swim down to a coral reef environment (Shedd Aquarium 2006).  

Picking out a large Napoleon Wrasse is easy when compared to the other relatively small reef organisms! The only thing that makes the determination a bit challenging is the multiple colors they display throughout their life cycle. Small juvenile Napoleon Wrasses in the reefs are easily identifiable with a black and white exterior (NOAA 2009). To view an example of these small juvenile organisms, take a gander at Massimo Boyer's photograph. In contrast, the larger juveniles have developed a pale green color and two black lines behind their eyes (NOAA 2009). With an increase in age, the fish develop a more prominent hump on the back of their neck, brighter colors in males like the green and blue spots and scribbles on their heads. More specifically, females develop a dimmer red-orange color on their upper body (NOAA 2009).

There are other differences when comparing the various stages of this magnificent fishes’ life. Sexual maturity is reached between five and seven years of age and, the most interesting difference is that this species is actually a protogynous hermaphrodite (NOAA 2009)! This implies that this species can have a female-to-male sex change (NOAA 2009). Although, the Wrasse ARE able to develop males directly from juveniles within the life cycle as well (Sluka 2000). This sex change typically occurs around nine years of age, according to Cathleen Bester from the Florida Museum of Natural History, even though Wrasses begin life with both gender organs (2013).

When they become adults, they adopt the name ‘initial phase male’, or ‘initial phase female’. Males that were born male, never have the chance to become a dominant male (Shedd Aquarium 2006). On the contrary, those that have undergone a sex change from male to female are the only fish that can become dominent males (Shedd Aquarium 2006). Therefore, the larger female wrasses are the only ones that have an opportunity to become a dominant male! They have this chance because they become “supermales” after their sex change if they are larger than the typical individual (Shedd Aquarium 2006). They also have distinct colors and patterns to attract more females than their lesser competition next mating period (Shedd Aquarium 2006).  Only supermales breed with numerous females in the temporary aggregation because of their dominance over the area and those within it due to their many advantages (Shedd Aquarium 2006). Isn’t it interesting the adaptations species have developed even within their own lifecycles?!?

Continue to Interactions to learn about who the Napoleon Wrasse associates with.

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