|Seasonal variation of gonado-somatic index and length-weight relationship in the horse mackerel, Trachurus trachurus (Osteighthyes: Carangidae) from the eastern Adriatic Sea|
Santic, M.; Pallaoro, A.; Jardas, I. (2008). Seasonal variation of gonado-somatic index and length-weight relationship in the horse mackerel, Trachurus trachurus (Osteighthyes: Carangidae) from the eastern Adriatic Sea. Cah. Biol. Mar. 49(4): 303-310
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723; e-ISSN 2262-3094
Secretory organs > Glands > Endocrine glands > Animal reproductive organs > Gonads
Trachurus trachurus (Linnaeus, 1758) [WoRMS]
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- Santic, M.
- Pallaoro, A.
- Jardas, I.
Seasonal changes in length-weight relationships (LWRs), gonado-somatic index (GSI) and condition factor in the horse mackerel Trachurus trachurus (Linnaeus, 1758) were studied. A total of 1136 specimens (580 males and 556 females) ranging from 15.7 to 37.0 cm in total length (TL) were collected in the eastern Adriatic Sea. Samples were taken at monthly intervals (January-December 2004) using bottom-trawls. The GSI reached maximum values in March and minimum in September. Including specimens collected in all seasons, the b values of length-weight relationships (W = aLb) showed that growth of both males and females was isometric. However, values of b varied during the year: positive allometric growth was noted in winter, while in late spring (May) and summer (June and July) negative allometric growth was observed. The condition factor was the lowest immediately after spawning (July) and the highest at the recovery phase (September). Seasonal variations of LWRs and condition factor of the horse mackerel were probably connected with the gonadal changes.