Coral fish
Coral fishAs a by standee over viewing the preparation and or the act of courtship in the coral reef fishes, one may think they have taken leave of their senses. The bicolor damselfish tends to quiver while performing a headstand. Blue pullers engage in a series of high-speed jumps. Lyretailfish swim in jerky zigzag patters. Frillfish goby undulates frantically against the sand. The Sergeant major rubs its body hard against the side of a rock or coral cavity and nips at these surfaces. (P 92)
These are methods by which coral reef fish readies a nest site or signals to prospective mates. Raped head-to-head circling and/or nose-to-belly nuzzling may signify that spawning is about to take place. Any of these performances are usually accompanied by dramatic changes in the patters or intensity of colors of the fish. Males and females tend to advertise their sex and availability through vibrant colors. This sexual dimorphism is most evident in such reef residents as groupers. The color patters change predictably from the "juvenile: to the "initial" subdued pattern of small adults to the "terminal" pattern in the largest adult males. The terminal male is the one with the brightest colors and gaudiest patterns.
The moon seems to play an important role in fish reproduction. According to Peter H. Pressley, it appears that the moon/s light may be as important as its gravitational pull. "Some fishes may use periods of maximum moonlight for effective nest guarding during the week or so it takes for many demersal eggs to incubate. Since the larvae of many dermersal-spawning species are light sensitive, bright moonlight may help to orient them towards the water's shallows after nighttime hatching." (P 96)
Regional weather patterns such as monsoons, periods of high wind velocity, and major current shifts affect procreation. "Extreme weather and fierce currents make it difficult for young fishes ready to assume reef niches to find their way out of pelagic waters.
Within these constraints, the reef fishes breed according to their individual seasonal patterns. Among the coral fish, there are at least four major spawning patterns.
"Some fishes migrate to spawn, some remain on the reef and spawn in pairs, some build reef nests where they guard their eggs, and a few actually protect their eggs, and a few actually protect their eggs in their mouths." (P 97)
The Sergeant majors of the genus Abudefduf are usually found in tropical and subtropical shallows all over the world. In the inter months, they are generally solitary or swim in small groups. From April to August, many schools are formed among them and the migration begins. During its reproductive season, the early morning hours are spent feeding in the upper layers of plankton. At about 10:00 AM and 4:30 PM the eating in interrupted as the male of the species gather in groups of a few...
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