Relationship between the Composition of Food Organisms of Skipjack Tuna Katsuwonus pelamis and Plankton in the Waters Adjacent tl Cronulla, New South Wales, Australia

濠洲 Cronulla 近海에 있어서 가다랭이의 먹이생物과 浮游생物의 組成과의 關係硏究

an analysis of stomach contents of skipjack tuna Katsuwonus pelamis and plankton samples collected during troll fishing operations showed that the abundance of some dominant organisms in tuna stomachs was related to their abundance in the plankton. Fish larvae mainly pilchards, Nyctiphanes australis, brachyuran and other decapod larvae and calanoid copepods are important food item for skipjack. The copepods Undinula vulgaris and Nannocalanus minor occurred consistently throughout the survey period in both stomach contents and plankton samples. U. vulgaris appeared to be a preferred food considering its high percentage composition in tuna stomachs compared with its low percentage composition in the plankton. Temora turbinata and N. minor may also serve as important food items for skipjack. The largest catches of the fish were made in January and February when plankton organisms were composed dominantly of N. australis, copepods and brachyuran larvae. The main stomach contents during this period were N. australis and brachyuran larvae.

1975年 12月에서 1976年 5月 사이에 濠洲 Cronulla近海에서 實施한 가다랭이 漁業試驗時 採集한 浮游生物과 가다랭이 胃內容物의 造成 및 量的 相互關係性을 分析硏究 하였다. 가다랭이의 먹이생물의 造成과 豊度는 富裕生物의 그것들과 잘 一致하였으며 그 主要먹이 생물로서는 Nyctiphanes australis, brachyura幼生, 정어리種漁 및 Copepoda등임을 밝혔다. 가장 많은 가다랭이 漁獲은 富裕生物組成上 N. australis와 brachyura유생이 가장 豊富했던 1月과 2月에 있었다. 特히 Copepoda중의 Undinula vulgaris는 가다랭이의 먹이생물中 선택적 기호성먹이로서 가치가 큰 것으로 나타났다.