نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه شیلات، دانشکده علوم دریایی، دانشگاه دریانوردی و علوم دریایی چابهار، چابهار، ایران.

2 گروه شیلات، دانشکده علوم و فنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران.

چکیده

مطالعه حاضر با هدف بررسی انتخاب‌پذیری طولی تورهای گوشگیر شناور سطحی رایج صید ماهی هوور معمولی (Thunnus tonggol) و تعیین اندازه چشمه بهینه صید در آب­های سیستان و بلوچستان (صیدگاه‌های چابهار، کنارک و رمین) از مهرماه 1395 تا خردادماه 1396 صورت پذیرفت. تورهای گوشگیر مورد بررسی دارای اندازه چشمه‌های 100، 110، 130 و 165 میلی‌متر به صورت کشیده بودند. در طول 45 مرحله دریاروی با قایق ­های فایبرگلاس و لنج چوبی تعداد 477 عدد ماهی هوور صید شد که داده­ های فراوانی طولی، وزن کل و دور آبشش و دور بدن آن­ها ثبت شد. تعداد 228 نمونه نیز کالبد شکافی شده و مراحل رسیدگی تخمدان آن­ها جهت برآورد طول بلوغ جنسی (Lm50) تعیین گردید. حداقل، حداکثر و میانگین (±انحراف ‌معیار) طول چنگالی نمونه­ ها به ترتیب 32، 90 و 13.35±55.1سانتی‌متر به دست آمد. روابط طول چنگالی- دور آبشش و طول چنگالی- حداکثر دور بدن به ترتیب /0.4955FL+ 0.5379= Gop   و 0.5879FL+0.5095  = Gmax محاسبه شد. طول بلوغ جنسی ماهی هوور 53.7 سانتی‌متر به دست آمد. با استفاده از روش سچین، انتخاب ­پذیری طولی تورهای گوشگیر با اندازه چشمه‌های 100، 110، 130 و 165 میلی­ متر به ترتیب 35، 38، 46 و 57 سانتی‌متر تعیین شد. با استفاده از ضرایب انتخاب‌پذیری و طول بلوغ جنسی ماهی هوور، چشمه استاندارد برای صید این گونه 170 میلی‌متر تعیین گردید. به دلیل عدم صید ماهیان نابالغ توسط چشمه‌ی 165 میلی‌متر، این چشمه می‌تواند مناسب باشد و این امر تأییدی بر محاسبه‌ی اندازه‌ی چشمه‌ی استاندارد این تور به روش سچین می‌باشد.   

کلیدواژه‌ها

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