Diel feeding periodicity of torrentfish (Cheimarrichthys fosteri) in two braided rivers of Canterbury, New Zealand
作者:
G. J. Glova,
P. M. Sagar,
C. R. Docherty,
期刊:
New Zealand Journal of Marine and Freshwater Research
(Taylor Available online 1987)
卷期:
Volume 21,
issue 4
页码: 555-561
ISSN:0028-8330
年代: 1987
DOI:10.1080/00288330.1987.9516259
出版商: Taylor & Francis Group
关键词: Ashley River;Rakaia River;noctur‐nally active;benthic prey;diet;bottom‐dwelling fish;stream invertebrates;riffle habitat
数据来源: Taylor
摘要:
TorrentfishCheimarrichthys fosteriHaast were collected at 4‐hour intervals over a full day in winter and summer, 1984–85, from the Ashley and Rakaia Rivers in Canterbury, New Zealand, to determine their diel feeding periodicity. Both populations fed, almost exclusively, from dusk to dawn in both seasons, with the quantity of food in their stomachs accumulating to peak levels by early morning. However, Ashley females had significantly less food in their stomachs than did males in summer, the season with a high incidence (91%) of females in spawning condition. Aquatic stages ofDeleatidiumspp. (Ephemeroptera: Leptophle‐biidae) and Chironomidae constituted from 85 to 98% by number and 63 to 80% by dry weight of all foods eaten. Chironomids (small prey) comprised up to 85% of the total foods eaten by number but only 17% by dry weight, whileDeleatidium(large prey) comprised up to 69% of the prey by number and 63% by dry weight. Numerically, chironomids were an important component in the torrentfish diet in both seasons in the Rakaia (71 to 75%), but only so in winter in the Ashley (85%). The reported daily feeding cycle is consistent with observations in a simulated stream, that torrentfish largely remain inactive during the day and come out to feed at night.
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