Digestive tract evacuation in northern squawfish (Ptychocheilus oregonensis)

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Digestive tract evacuation in northern squawfish (Ptychocheilus oregonensis) (170–1900 g) was studied in fish allowed to feed voluntarily on salmon (4–70 g) at three water temperatures (10, 15, and 20 °C). Squawfish were sacrificed at 1- or 2-h intervals until evacuation approximated 90%. Amount of food evacuated for a given time interval increased approximately three times as the temperature was increased and as the prey weight was increased and two times as the predator weight was increased. The 90% emptying time (ET90) decreased by about two thirds as the temperature doubled and by about one half as the predator weight increased 10 times, but approximately doubled when the prey weight increased 4 times. Two-fish meals (17–20 g each, 35–39 g total) were evacuated more slowly than meals of one fish weighing 17–20 g, but at the same rate as meals of one fish weighing 35–40 g. Equations derived are easily applied to a wide range of water temperatures, prey weights, and predator weights.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Digestive tract evacuation in northern squawfish (Ptychocheilus oregonensis)
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f88-064
Volume 45
Issue 3
Year Published 1988
Language English
Publisher Canadian Science Publishing
Contributing office(s) Western Fisheries Research Center
Description 6 p.
First page 548
Last page 553