Dạng sinh trưởng quần đàn và phổ thức ăn của cá đù mõm nhọn Chrysochir aureus (Richardson, 1846)

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Tác giả: Viết Văn Mai

Ngôn ngữ: Vie

Ký hiệu phân loại:

Thông tin xuất bản: Khoa học (Đại học Trà Vinh) 2022

Mô tả vật lý: 74-81

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ID: 407785

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Nghiên cứu về dạng sinh trưởng quần đàn và phổ thức ăn của cá đù mõm nhọn Chrysochir aureus (Richardson, 1846) được thực hiện từ tháng 6/2021 đến tháng 01/2022 tại vùng biển từ tỉnh Sóc Trăng đến tỉnh Bạc Liêu. Cá được thu định kì hằng tháng bằng tàu lưới kéo đáy. Mẫu dạ dày cá được cố định trong dung dịch formol 4% để thức ăn không bị tiêu hóa. Kết quả phân tích 198 cá đực và 215 cá cái cho thấy chiều dài toàn thân và khối lượng thân cá đù mõm nhọn có mối quan hệ hồi quy rất chặt chẽ theo phương trình hàm số mũ: W cá đực = 0,0064L3,1425, R2 = 0,9735 với chiều dài toàn thân dao động 14,0 - 40,0 cm (cá đực)
W cá cái = 0,0046L3,2425, R2 = 0,9504 với chiều dài toàn thân dao động 13,5 - 41,0 cm (cá cái). Chỉ số tương quan giữa chiều dài ruột và chiều dài toàn thân của cá nhỏ hơn 1 (RLG = 0,08 ± 0,02 cm ở cá nhỏ và RLG = 0,08 ± 0,04 cm ở cá lớn). Điều này chứng tỏ cá có tính ăn động vật. Số lượng cá thể đang ở tình trạng đói mồi chiếm tỉ lệ cao trong quần đàn. Thành phần thức ăn trong dạ dày của cá nhỏ là ba loại thức ăn (cá con, tôm và thức ăn khác), cá lớn là sáu loại thức ăn (cá con, tôm, mực, cua, con rươi và thức ăn khác). Phổ thức ăn của cá nhỏ hẹp hơn so với cá lớn., Tóm tắt tiếng anh, A study on growth and food spectrum of Reeve's croaker was carried out from June 2021 to January 2022 in the coastal areas from Soc Trang to Bac Lieu provinces. Fish samples were collected monthly by bottom trawl. Fish stomachs were fixed in a 4% formol solution to prevent feed items from being digested in the stomach. The analysis of 198 male and 215 female samples showed that the total length (L) and body weight (W) of the fish had a regression relationship according to the equations Wmale = 0.0064L3,1425 and R2= 0.9735 (total length ranged 14.0 - 40.0 cm) and Wfemale = 0.00463.2425 and R2 = 0.9504 (total length ranged 13.5 - 41.0 cm). The relative length of the gut (RLG) <
1 (RLG = 0.08 ± 0.02 cm in immature fish and RLG = 0.08 ± 0.04 cm in mature fish), indicated that Reeve's croaker was a carnivorous fish. Many individuals in the population have no food in their stomachs. The immature fish eat three types of food (small fish, shrimp and other food) while mature fish eat six types of food (small fish, shrimp, squids, crabs, nereid and other food). The feed spectrum of immature fish was narrower than that of mature fish.

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