Behavioural responses of sablefish, Anoplopoma fimbria, to bait odour

Abstract

A behavioural bioassay was used to determine the response threshold to squid extract of sablefish, Anoplopoma fimbria, held at three different feeding regimens. Sablefish responded to the odour of bait by changing swimming activity and turning behaviour. The response threshold to bait odour was influenced by both the amount of food eaten and the duration of food deprivation. The total concentration of amino acids in the bait extract was assumed to determine the response threshold as chemical fractionation studies have shown that this class of compounds is essential for the stimulatory capacities of food extracts. When fed to satiation (9.4% wet body weight) and tested after one day of food deprivation, the mean response threshold to total dissolved free amino acids was 4.4 × 10−8m (range=7.6 × 10−8 to 3.6 × 10−8m). When fed at 1.6‐2.3% wet body weight, the threshold sensitivity had increased to a mean value of 1.8 × 10−10m (range=8.4 × 10−10 to 7.0 × 10−11m) after one day of food deprivation; after four days of deprivation, the sensitivity had increased even further to a mean value of 1.4 × 10−11m (range=1.6 × 10−10 to 1.4 × 10−12m). It was also apparent that the intensity of behavioural responses to the bait odour increased with both stimulus concentration and duration of food deprivation. These results suggest that sablefish intensify their search for prey under increased feeding motivation. The active space of a bait source was estimated from the threshold values obtained. Depending on state of food deprivation, rate of chemical release from the bait and the current velocity, maximum lengths of active space within which sablefish would exhibit food searching responses vary from 10 m to several km. Stock assessment based on catch data from baited gear will need techniques that take into account those factors influencing active space for food searching.

Behavioral responses of two deep-sea fish species to red, far-red, and white light

“…A. fimbria are capable of sustaining long periods of food depravation (Sullivan & Smith 1982), likely an adaptation to the periodic nature of food availability in the deep sea. Lokkeborg et al (1995) demonstrated that response to a low-concentration odor plume was higher in food-deprived A. fimbria, whereas satiated individuals spent the majority of their time resting on the bottom, away from the light during periods of exposure to odor plumes. We propose that the observed A. fimbria behavior around our baited camera was the result of competing sensory inputs.…”

Effect of several feeding stimulants on diet preference by juvenile gibel carp (Carassius auratus gibelio), fed diets with or without partial replacement of fish meal by meat and bone meal

“…Ž Many behavioural bioassays have been designed Carr and Chaney, 1976;Mearns, . 1985;Løkkeborg et al, 1995 . Such methods can be used to test a large number of stimuli within short periods.…”

Relative selectivity in trawl, longline and gillnet fisheries for cod and haddock

“…Fish with low condition factor, i.e. thin fish, probably have higher nutritional requirements and thus higher feeding motivation (Løkkeborg et al, 1995). It is likely that these fish are caught in higher proportions by longline, which exploits the feeding behaviour of the target fish.…”