بررسي مقايسه‌ايي برخي از خصوصيات زيست شناختي ماهي زمين‌كن دم‌نواري (Platycephalus indicus) در آب‌هاي سواحل بندرعباس

A comparison study on some biological aspects of Platycephalus indicus in coastal waters of Bandar Abbas

مطالعه حاضر با هدف بررسي برخي از خصوصيات بيولوژيكي و پويايي جمعيت ماهي زمين‌كن دم‌نواري طي يك دوره يك ساله از خرداد 1390 تا ارديبهشت 1391 در آبهاي ساحلي بندرعباس بررسي شد. در مجموع 1106قطعه ماهي مورد بيومتري قرار گرفت. همچنين هر ماه 35 قطعه ماهي به منظور بررسي وضعيت توليد‌مثلي و سنجش وزن گناد، وزن كبد و تعيين مراحل جنسي به آزمايشگاه منتقل شدند. تعيين سن 250 نمونه بوسيله برش اتوليت صورت گرفت، سن تخمين زده شده براي ماهيان ماده بين يك تا بيش از هفت و براي ماهيان نر بين يك تا بيش از چهار سال تعيين شد. رابطه وزن و طول (طول كل) براي ماهيان نر1635/3L004/0W= و براي ماهيان ماده 1293/3L0042/0W= محاسبه شد. كه نشان دهنده رشد ناهمگون اين ماهي است. نرخ مرگ و مير طبيعي براي ماهيان ماده 886/0 و براي ماهيان نر 736/0 بر سال، و مرگ و مير صيادي براي جنس ماده 43/1 و جنس نر 62/1 بر سال محاسبه شد. رشد بر اساس معاله برتالنفي محاسبه شد.

Study was conducted to determine some biological characteristics and population dynamic of Platycephalus indicus were studied during one year from May 2011 to March 2012 in the coastal waters of Bandar Abbas. A total of 1106 samples were collected. Also, each month 35 fish was chosen and transferred to the laboratory for evaluation of spawning season. The ages of 279 specimens were determined by sectioned otoliths. The ages of the females were estimated to be between 1 to more than 7,while the ages of the males were from 1 to more than 4.The relationship between weight and length (Total length) can be expressed as W=0.004L3.16 35 for male and W = 0.0042L3.1293 for female. This equation indicates that keeled mullet has allometric growth. The values for natural mortality (M) resultant coefficient were M = 0.886 year-1 for females and 0.736 year-1 for males, and the estimated Z values were 1.43 year-1 for females and 1.62 year-1 for males. These ages were then ®tted to the von Bertalanffy growth equations. Equations obtained were Lt = 43.4 (1-exp(-0.45 (t +0.32))) for males, and Lt = 63 (1-exp(-0.50(t + 0.30))) for females.