Caranx crysos

blue runner | Black Jack | Bluestripe Jack | Boca Abou | Golden Jack | Green Jack | Hardnose | Hardtail | Hardtailed Jack | Carangoides crysos
Caranx crysos
Caranx crysos, Abrolhos, Bahia, Brazil, Photo: Graham Edgar


Mediterranean, Temperate northern Atlantic, Tropical Atlantic/Caribbean


Slightly elongate silver body with black margins on tips of tail lobes. Juveniles with about seven dark bars on sides, found drifting with sargassum mats. Forms schools usually not far from the shore.


Max Size: 70 cm

Sea Temperature Range: 6.8-29.8°C

Depth: 0-100m

Habitat Generalization Index: N/A

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.

Conservation and Rarity

IUCN Status: Least Concern

Occurrence: Infrequent (3.3% 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 (5 per transect)

Abundance is calculated as the average number of individuals recorded per RLS transect, where present.

Edit by: Joe Shields