بیولوژی تولید مثل گونه سنگسر مخطط (pomadasys stridens forsskal, 1775) در آب های بخش شمالی خلیج فارس (استان بوشهر)

ماهی سنگسر مخطط (pomadasys stridens) پراکندگی گسترده ای در خلیج فارس دارد. اختصاصات تولید مثلی این ماهی کمتر مورد مطالعه قرار گرفته است. نمونه های سنگسر مخطط ماهیانه از خرداد 1389 تا اردیبهشت ماه 1390 از اسکله های صیادی بندر بوشهر از طریق صیادان محلی جمع آوری و برای مطالعات بعدی به مرکز تحقیقات شیلات بوشهر و سپس به دانشگاه صنعتی اصفهان انتقال یافت. از مجموع 540 ماهی مورد مطالعه، 155 قطعه نر و 385 قطعه ماده بودند. طول کل ماهی ها با دقت میلی متر و وزن کل آنها در حد 0/1 گرم اندازه گیری شد. قطعاتی از گناد برای مطالعه بافت شناسی به مدت 24 ساعت در فرمالین 10 درصد و پس از آن در الکل 70 درصد نگهداری شد. طول کل ماهیان ماده 12/6 تا 23 سانتی متر و نرها 11/7 تا 22 سانتی متر بود. گستره وزنی ماده ها از 27/4 تا 144/8 گرم و برای نرها از 21 تا 124/9 گرم به دست آمد. ماده ها اندازه بزرگ تر از نرها نشان دادند گروه سنی برای هر دو جنس نر و ماده بین +1 تا +8 متغیر بود. میزان نمایه نمو گنادی gsi در سنگسر مخطط دارای دو اوج بود که اولی کوچک تر و در آذر ماه و اوج دوم بزرگ تر بود که در اسفند ماه مشاهده شد. کمینه و بیشینه هماوری مطلق به ترتیب برابر با 28597 و 198672 عدد تخمک و هماوری نسبی 288 و 1558 عدد تخمک به ازای هر گرم از وزن بدن به دست آمد. نسبت جنسی در تمام زمان نمونه برداری 1:3/3 (m/f) محاسبه گردید. با بررسی نمایه نمو گنادی، قطر تخمک و بافت های گنادی ، فصل تولید مثل این گونه در آذر و اسفند به دست آمد.

Reproductive Biology of Stripped Piggy (Pomadasys stridens Forsskal, 1775) in Northern Part of Persian Gulf (Bushehr)

Stripped piggy (Pomadasys stridends) is widely distributed in coastal waters of Persian Gulf. However, the reproductive characteristics of this fish were underresearched. Specimens of Pomadasys stridens were collected from the local catches at Bushehr fishery harbor from May 2010 to April 2011, by regular monthly collections. A total of 540 specimens, including 155 males and 385 females were collected and transported to Bushehr fishery research center and then to Isfahan university of technology for analysis. The total length (in millimeter) as well as the total weight (in 0.1 grams) of the fish was carefully recorded. The total length of the mature fish ranged from 12.6 cm to 23 cm (females) and 11.7 cm to 22 cm (males) and their total weight ranged from 27.4 g to 144.8 g (females) and 21 to 124.9 (males). In both length and weight, females showed larger size than males. Age groups in both sexes were determined and ranged between 1 and 8 years. Monthly distribution of GSI for female and male P. stridens, showed that the GSI values have two peaks, the first one which was smaller occurred in December and the second one, the maximum, was in March. The minimum and the maximum of absolute fecundity were 28597 and 198672 per gram of body weight, respectively and the relative minimum and maximum fecundity was 288 and 1558 per gram of body weight, respectively. The mean of the sex ratio was 1: 3.3 (M/F). According to the GSI, ova diameter and histological observations, spawning period was determined from December to March.Stripped piggy (Pomadasys stridends) is widely distributed in coastal waters of Persian Gulf. However, the reproductive characteristics of this fish were underresearched. Specimens of Pomadasys stridens were collected from the local catches at Bushehr fishery harbor from May 2010 to April 2011, by regular monthly collections. A total of 540 specimens, including 155 males and 385 females were collected and transported to Bushehr fishery research center and then to Isfahan university of technology for analysis. The total length (in millimeter) as well as the total weight (in 0.1 grams) of the fish was carefully recorded. The total length of the mature fish ranged from 12.6 cm to 23 cm (females) and 11.7 cm to 22 cm (males) and their total weight ranged from 27.4 g to 144.8 g (females) and 21 to 124.9 (males). In both length and weight, females showed larger size than males. Age groups in both sexes were determined and ranged between 1 and 8 years. Monthly distribution of GSI for female and male P. stridens, showed that the GSI values have two peaks, the first one which was smaller occurred in December and the second one, the maximum, was in March. The minimum and the maximum of absolute fecundity were 28597 and 198672 per gram of body weight, respectively and the relative minimum and maximum fecundity was 288 and 1558 per gram of body weight, respectively. The mean of the sex ratio was 1: 3.3 (M/F). According to the GSI, ova diameter and histological observations, spawning period was determined from December to March.