Morphology Data of Thunnus obesus
Identification keys
Abnormalities
Main Ref. Collette, B.B., 2001
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

Descriptive characteristics of juvenile and adult

Striking features none
Body shape lateral fusiform / normal
Cross section oval
Dorsal head profile more or less straight
Type of eyes more or less normal
Type of mouth/snout more or less normal
Position of mouth terminal
Type of scales
Diagnosis

This large species is distinguished by the following characters: robust, fusiform body, slightly compressed from side to side; total gill rakers on first gill arch 23-31; dorsal fins separated only by a narrow interspace, the second followed by 8-10 finlets; anal fin followed by 7-10 finlets; pectoral fins moderately long (22 to 31% of fork length) in large specimens (over 110 cm FL), but very long (as long as in Thunnus alalunga) in smaller specimens; 2 flaps (interpelvic process) between pelvic fins; very small scales on body; corselet of larger and thicker scales developed, but not very distinct; caudal peduncle very slender, with a strong lateral keel between 2 smaller keels; ventral surface of liver striated; swimbladder present. Colour of back metallic dark blue, lower sides and belly whitish; a lateral iridescent blue band runs along sides in live specimens; first dorsal fin deep yellow, second dorsal and anal fins light yellow, finlets bright yellow edged with black (Ref. 9684).

Ease of Identification

Meristic characteristics of Thunnus obesus

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 23 - 31
Vertebrae
preanal
total 39

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 2
Finlets No. Dorsal   8 - 9
Ventral  7 - 8
Spines total 13 - 14
Soft-rays total 14 - 15
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 14 - 14

Paired fins

Pectoral Attributes  more or less normal
Spines     
Soft-rays   
Pelvics Attributes  more or less normal
Position    thoracic  beneath origin of D1
Spines     
Soft-rays   
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Reyes, Rodolfo B.
Modified by Capuli, Estelita Emily
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cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17