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INTRODUCTION

The occurrence of color morph variations has been documented for some species of reef fishes of the families Serranidae (Graves & Rosenblatt 1980; Medioni et al. 2001), Cirrhitidae (DeMartini & Donaldson 1996), Syngnathidae (Guimarães 1999), Ostraciidae (Pattengill-Semmens 1999) and Pomacentridae (Planes & Doherty 1997). Among Pomacanthids, a case of melanism inHolacanthus tricolorwas detected south of the Caribbean island of Porto Rico (Colin 1982). Holacanthus ciliaris is a common reef fish species of St. Paul’s Rocks (Feitoza et al. in press) and its color variants there were first reported by members of the Cambridge Expedition to St. Paul’s Rocks in 1979 (Lubbock & Edwards 1981; Edwards & Lubbock 1983) but there are no additional registers for H. ciliaris color morphs in the entire spectrum of their geographic range. In a recent visit to the Rocks I had the opportunity to make a photographic register of many of these bizarre fishes. All the color variations observed in H. ciliaris are presented in this paper.

METHODS

St. Paul’s Rocks are an oceanic group of small islands located 960 km off the northeast coast of Brazil, lying just north of the equator (00 55’N; 29 21’W). They are emerged bits of the Mid- Atlantic Ridge, caused by an up thrust of the oceanic upper mantle (Melson 1966). A general account of they’re ecology is provided by Edwards & Lubbock (1983a).

I visited the Rock’s as a member of a documentary expedition in november/1999. On that occasion, 16 dives were

made

and

a

total

of

Tropical Fish Hobbyist

Above: This is the normal coloration of H. ciliaris, as found off the continental Brazilian coast.

Opposite: The coasts of St. Paul’s Rocks in the Atlantic are home to a number of unique color variants of the queen angelfish, Holacanthus ciliaris. The most common is the golden one, photographed in its natural habitat.

approximately 20 hours of underwater observations were completed.

The fishes were photographed using a reflex still camera in an underwater housing loaded with color slide or negative film. They are also filmed with a digital mini- DV camcorder camera in an underwater housing.

RESULTS

The following types of H. ciliaris color morphs were found:

  • GOLD MORPH

This is the predominant coloration in the St. Paul’s population and differs from the Brazilian coast and Caribbean populations by having a bright orange coloration in the body in contrast to the normal pattern of yellow and blue body color. The Saint Paul’s population also has shorter tips of the dorsal and anal fins, which do not reach the end of the caudal fin.

  • ALL WHITE MORPH

  • WHITE MORPH WITH ORANGE

AND BLACK BLOTCHES

  • BRIGHT BLUE MORPH WITH A

PALE CAUDAL FIN

  • BRIGHT BLUE MORPH WITH A PALE CAUDAL FIN AND YELLOW FACE

  • BRIGHT BLUE MORPH WITH YELLOW CAUDAL AND PECTORAL FINS

  • BRIGHT BLUE MORPH WITH BLACK AND WHITE CAUDAL AND PECTORAL FINS, WHITE OPERCULE AND MOUTH

DISCUSSION OF GENETIC AND BIOGEOGRAPHIC CONJECTURES

The occurrence of intraspecific color morphs in fish populations are relatively common and can be attributed to many reasons, such as (1) ontogeny; (2) behavioural responses and communication, and (3) genetic differentiation. When the colour changes are a result of ontogeny or by induced responses of the skin pigments, they could be variable with the age of the fish, time of day, and social interactions (e.g. Nemtzov 1993) and could be distributed all along the species’ geographic

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