Grammatorcynus bilineatus, Great barrier Reef, Australia, Photo: Rick Stuart-Smith
Grammatorcynus bilineatus, Coral Sea, Australia, Photo: Andrew Green
Distribution
Tropical Indo-Pacific
Description
Elongate silver body, greenish on back, double lateral line, lower line departing on perpendicular angle behind pectoral fin and re-joining on tail base. Common large mackerel around reefs, difficult to distinguish from G. bicarinatus (Shark Mackerel), which also has 2 lateral lines, but has proportionally smaller eye.
Information
Max Size: 100 cm
Sea Temperature Range: 22.4-31.2°C
Depth: 1-50m
Habitat: Coral Reef, Rocky Reef
Habitat Generalisation Index: 0.4
Also referred to as the SGI (Species generalisation index), this describes the habitat niche breadth of the species.
Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most
hard substrates within their range (generalists). Learn more here
Rarity
IUCN Threat Status: Least Concern
Occurrence: Infrequent (5% of sites)
Occurrence describes how often the species is found on surveys within its distribution.
It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed
Abundance: Few (2 per transect)
Abundance is calculated as the average number of individuals recorded per RLS transect, where present.
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