Comparative study on feeding strategy and activity patterns of two Antarctic fish: Trematomus newnesi Boulenger, 1902 and Gobionotothen gibberifrons (Lonnberg, 1905) (Pisces, Nototheniidae) under different light conditions

• Main Authors: Edith Fanta, Ana Aparecida Meyer, Sonia Regina Grotzner, Marcia Fabiana Luvizotto
• Format: Report
• Language: English
• Published: Universidade Federal do Parana 1994
• Subjects: 591.5; Admiralty Bay; Antarctic; King George Island; The Antarctic; Antarc*
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=8839; http://id.nii.ac.jp/1291/00008839/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=8839&item_no=1&attribute_id=18&file_no=1

南極半島にあるキングジョージ島, アドミラルティ湾ではノトセニア科の2種Trematomus newnesiとGobionotothen gibberifronsは生育場所を共にする底生魚である。しかし, 水槽内での飼育観察の結果, 両種の行動は, 24時間連続照明の場合と10時間暗, 14時間明の連続照明の場合とでは相違した。すなわち, 24時間照明の場合, G. gibberifronsはT. newnesiより, 早く, 長時間遊泳したが, 呼吸頻度は低かった。ところが, 10/14周期の場合, 両種の関係は逆転した。また, 生きている端脚類を餌として与えた場合, T. newnesiの採餌成功率は, G. gibberifronsの15倍と高い。形態観察の結果, 視覚の差が, これらの行動の差をもたらしていると考えられる。一方, G. gibberifronsを本種だけで飼育した場合, 採餌は水槽の表面付近でなされるが, T. newnesiが共存すると, G. gibberifronsは底付近でのみ採餌するようになる。餌の飲み込み行動にも差があり, これは味蕾の分布が両種で異なっていることによるものであろう。生育場所を同じくする両種は, それぞれの行動を違えることによって共生している。 The behavior of Trematomus newnesi BOULENGER, 1902 and Gobionotothen gibberifrons (LONNBERG, 1905) (Pisces, Nototheniidae), caught in Admiralty Bay, King George Island, during the Antarctic summer, is compared. Experiments were done at 2℃ and two different light conditions. If both species are kept together in light for 24 hours, G. gibberifrons is usually more active than T. newnesi, swimming for longer periods, with higher speed, but showing lower respiratory frequency. An inversion occurs at 10/14 photo period. Rhythms may be observed in both light conditions for some behavioral patterns. If compared to G. gibberifrons the feeding success is 15 times higher for T. newnesi : it seems to detect shapes and movements at longer distances, swimming directly toward the prey, ingesting and swallowing at once. G. gibberifrons, in the presence of T. newnesi, takes a long time to react to the food and catches it only at the bottom, swimming through short jumping movements. If not in the presence of T. newnesi, it may catch the prey near the surface, with slow movements, but in any case food must be tasted inside the mouth before it is accepted as such. G. gibberifrons has more taste buds in the upper lips and in the pharyngeal region of the branchial arches than T. newnesi. The eyes seem better developed in T. newnesi. They are differently planced in both species, leading to different visual fields. One can conclude that when G. gibberifrons and T. newnesi share the same ...