دراسة العمر والنمو لأسماك الجحش Lethrinus nebulosus (Forskal, 1775) (Fam. Lethrinidae) في المياه الساحلية لمحافظة حضرموت (اليمن)

Abstract

Emperor fishes ( Lethrenus nebulosus), is one of the commercially fish species landed in Hadhramout fish markets. These fishes targeted to be transported abroad due to its favorable and tasty meat. These fishes are mainly caught in Hadhramout coastal waters by artisanal fleets, which mainly caught by long line ,traps and trawl fishing gears. For the purpose of this study, fish samples were collected from Al sheher and Mukalla fish markets. These fishes were taxonomically identified and some biological aspects were studied as well as fish aging were conducted. The results of size composition shows that, moderate sized fishes (30-40cm) was dominated the sample studied. Aging was done by means of otoliths and scales where maximum aged fishes obtained was four (IV) years old. Fishes of the ages 0-II was dominate the sample which might be due to that bigger and older ones are sold outside fish markets. The length weight relationship shows that b and a values were 2.9 and 0.02 respectively whereas the average value of condition factor (k) was 1.5.The results shows that the growth of Emperor fishes, L. nebulosus was faster at the first year of old. Aging by means of otoliths is the most accurate while a scale reading is the appropriate method that scales is easy to get from fish markets.