پايش كمي، كيفي و بهداشتي بچه‌ماهي آزاد توليدي در مجتمع تكثير و پرورش شهيد باهنر استان مازندران تا رهاسازي به درياي خزر

Hygienic, quantitative and qualitative monitoring of Salmo trutta caspius fingerling in Shahid Bahonar culturing and propagation complex in Mazandaran until their releasing to the Caspian Sea

پروژه پايش كمي، كيفي و بهداشتي ماهي آزاد در مركز تكثير و پرورش ماهي شهيد باهنر كلاردشت تا مرحله رهاسازي به دريا طي سال‌هاي 83-1382 انجام شد. در اين بررسي تعداد 118 عدد ماهي مولد از مصب رودخانه تنكابن با ميانگين وزني 35/2 كيلوگرم صيد گرديد. تعداد 79 عدد از مولدين جهت دست‌يابي به رسيدگي جنسي به‌مدت دو ماه در آب شيرين نگهداري شدند. 197 قطعه ماهي مولد ماده در سال 82 تكثير شد. ميانگين وزني و طولي مولد ماده تكثير شده به‌ترتيب 92±2330 گرم و 54/1±4/56 سانتي‌متر و ميانگين وزني و طولي مولد نر تكثير شده به‌ترتيب 13±2350 گرم و 86/0±60 سانتي‌متر و نسبت ماهي نر به ماده 2:2 بوده است. تعداد تخم استحصالي طي فصل تكثير 568989 عدد (به‌ازاي هر مولد 2888 عدد) و ميانگين‌هاي درصد لقاح، درصد بازماندگي تخم تا مرحله چشم‌زدگي و درصد بازماندگي تا مرحله تخمه‌گشايي به‌ترتيب 86/0±97 ، 39/2±95 و 22/1±90 درصد تعيين گرديد. تعداد و درصد لارو به‌دست آمده از كل تخم استحصالي 486523 عدد (5/85 درصد) و ميانگين به‌ترتيب 10±96 ميلي‌گرم، 12±130 ميلي‌گرم و 7±200 ميلي‌گرم بوده است. ضريب تبديل غذايي در اوزان مختلف به‌ترتيب 87/0: 130-96 ميلي‌گرم، 95/0: 200-130 ميلي‌گرم، 1: 400-200 ميلي‌گرم، 1/1: 2000-400 ميلي‌گرم، 2/1: 5000-2000 ميلي‌گرم و 4/1: بيش از 5 گرم محاسبه گرديده است. حداقل و حداكثر وزن، طول و ضريب چاقي بچه‌ماهيان يك تابستانه به‌ترتيب 1 گرم و 95/21 گرم، 2/5 سانتي‌متر و 6/12 سانتي‌متر، 01/1 و 22/1 تعببن گرديد. در ماهيان دو تابستانه حداقل و حداكثر وزن و طول به‌ترتيب 5 و 80 گرم، 80/3 و 19 سانتي‌متر بوده است. بچه تعداد 756 عدد بچه‌ماهي در دامنه وزني 20-95/1 گرم مورد بررسي انگل‌شناسي قرار گرفت كه، 54 درصد آن به انگل Gyrodactylus، 2/14 درصد به انگل Myxobolus و 8/13 درصد به انگل سفيد يا آلوده بودند. در آزمايش مقاومت در برابر شوري، درصد ماندگاري بچه‌ماهيان يك تابستانه در آب شور درياي خزر 53 درصد و براي بچه‌ماهيان دو تابستانه 100 درصد بود. پارامترهاي فيزيكوشيميايي (TDS، EC، PH، DO، Po4-3، NH4+، No2-، Co32-، BOD5، Ca+2، Mg+2) درجه حرارت آب ورودي كارگاه، چشمه و رودخانه تنكابن اندازه‌گيري گرديده است.

This study has been conducted for duration of two years (2003-2004) with the aim of hygienic, quantitative and qualitative monitoring of fingerling fish (Salmo trutta caspius). A total of 118 brood stock fishes (Brown trout) were caught from opening place of Tonekabon River with an average weight of 2.35 kg. 79 of adult fishes were kept in fresh water fish farm to reach sexual maturity for duration of two months. During breeding time (along with other adults that were already kept from previous years), a total of 197 fishes were bred and the results were as follow: The average weight (kg) and length (cm) of propagated females were 2.33±0.92 and 56.4±1.54 respectively. But in males the average weight (kg) and length (cm) of propagated fishes were 2.35±13 and 60±0.86 respectively. At this time the males ratio number to females were 2:2 and the number of egg yield during propagation was 568989 (each matured female was holding 2888 of eggs). The average percentage of fertilization, eggs eyes survival and percentage of hatching survival were 97±0.86, 95±1.39 and 90±1.22 respectively. The total number of and percentage of larvae earned from obtainable eggs were 486523 and 85.5% respectively. The average larvae weight (after post hatching), larvae (mix feeding) and fry fishes (active feeding) were 96±10, 130±12, and 200±7 milligrams respectively. Therefore, food conversion in different weights were 96-130 mg :0.87, 130.200 mg:0.95, 200-400 mg:1,400- 2000 mg:1.1,and for conversion of 1.4 need more than 5 grams respectively. The biometric factors on fingerlings are related to those fingerlings which their propagation happened during 2001 and 2002. Maximum and minimum weight, length and fat coefficient of one year class were 21.95 and 1 gram, 12.6 and 5.2 cm, 1.22 and 1.01 respectively. Maximum and minimum weight and length of two years class were 80 grams and 5 grams, 19and 3.8cm respectively. From parasitological point of view about 756 fingerlings with the weight of 1.95-20 grams were under consideration. In this connection the percentage of parasitic infestation such as gyrodactylus, myxobolus and scyphidia were 54, 14.2 and 13.8 respectively. The resistance of those fingerlings and direct exposure to 12.5 ppt (Caspian Sea water) for one-year and two-year classes were 53 and 100 percent. The physicochemical parameters in this survey for main entrance water to fish farm, stream and Tonecabon river water were determined as follows: TDS, EC, PH, DO, PO4 3- , NH4 + , CO3 2- , BOD5, Ca 2+ and Mg 2+ .