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Coral reef fishes
The most species-rich vertebrate
communities known
Seven important families of coral
reef fish
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Gobiidae
Serranidae
Labridae
Chaetodontidae
Zanclidae
Acanthuridae
Tetraodontidae
4000-4500 species worldwide,
comprising 25% of the known
species of marine fish
Latitudinal gradient in species
richness holds for all marine fishes
• Possibly a result of the high number of
coral reef fishes, which are found only in
the tropics
However, do coral reef fishes show such a
gradient within the tropical and subtropical
regions?
• Not clearly, and their species richness is
not clearly linked with reef area, which
does show a gradient within the tropical
and subtropical regions (more reef area at
the equator)
Longitudinal patterns of coral reef
fish species richness
• Most species-rich areas are in the western
Pacific, which also has the highest
richness of coral species
• Investigators have assumed that this is the
center of origin of the group
Also, a general pattern of less
species richness in the Atlantic
as compared to the Pacific exists
The relationship between reef
area and fish diversity
longitudinally is clearly
demonstrated
The high species richness in the western
Pacific could be because of
• Sea-level changes during the period 5-2
mya, resulting in basins of water being
isolated, where allopatric speciation of
fishes could then take place
• High endemism levels in western Pacific
support this idea, although high endemism
is also found in Arabian Sea, Hawaii, and
the Red Sea
Low species richness of eastern
Pacific may be because of
• Westward-flowing currents
• Lack of stepping stones across the Pacific
Lower species richness of Atlantic compared
to Pacific may be because of
• Lack of suitable refuges during times of
environmental stress leading to
• Generalist species and
• Lack of specialists
• Ex. Parrotfish
Take-home message
• Reef area and current patterns explain
some, but not all, patterns in coral reef fish
species richness
Expedition to coral triangle identifies many
new species