The effect of turbidity and illumination on the reaction distance and search time of the marine planktivore Gobiusculus flavescens

Abstract

Both reduced illumination and increased turbidity caused a significant reduction in reaction distance of Gobiusculus flavescens. The longest reaction distance, 18.9 cm for larger prey (Calanus finmarchicus), occurred at a light level of 80 μmol m −2 s −1 compared to 12.9 cm for a smaller prey (Acartia clausi) at 8 μmol m−2 s−1. Above a light saturation level of 10 μmol m−2 s−1, additional light had little influence on reaction distance. In the turbidity experiments, the longest reaction distances were measured at turbidity levels of 10–20 JTU. Prey size influenced reaction distance at all tested light levels. Search time was influenced by prey size only at low illumination. With increasing turbidity, reaction distance to a group of prey was longer than to one prey.

Fish or jellies—a question of visibility?

“…3) that the light flux in the basin waters will be several orders of magnitude lower in Lurefjorden, suggesting a severe reduction in the potential for visual feeding (Giske and Aksnes 1992; Aksnes and Giske 1993; Aksnes and Utne 1997). The importance of light flux and water optics for predator-prey relations has been well documented experimentally (Vinyard and O'Brien 1976;Wright and O'Brien 1984;Montgomery et al 1989;Gregory and Northcote 1993;Thetmeyer and Kils 1995;Utne 1997) and in the field (Kaartvedt 1996;Kaartvedt et al 1996). Hence, we cannot reject the hypothesis that a much higher light absorbance in the basin water of Lurefjorden (Figs.…”

“…Light limitation in visual foraging-The present work and the study of Eiane et al (1997) emerged as a result of theoretical and experimental work on how predation by fish is affected by light and optical properties of prey and environment (Aksnes and Giske 1993;Giske et al 1994;Aksnes and Utne 1997;Utne 1997). Furthermore, field studies on the mesopelagic fish Maurolicus muelleri, an important zooplanktivore in Norwegian fjords, have revealed that both the feeding and the vertical behavior are highly sensitive to the prevailing light conditions of the water column (Giske and Notes Aksnes 1992;Baliño and Aksnes 1993;Rosland andGiske 1994, 1997).…”

Small-scale patterns in distribution and feeding of Atlantic mackerel ( Scomber scombrus L.) larvae in the Celtic Sea with special regard to intra-cohort cannibalism

“…Since measurements were taken at mid-depth of each depth stratum, it is possible that the bulk of mackerel larvae had encountered suboptimal light levels on the second day of the drift study. However, reactive distance of fish larvae to their potential prey is also positively correlated to prey size (Aksnes and Utne 1997;Utne 1997) and mobility (Utne-Palm 1999). Therefore one might expect a higher proportion of larger and more mobile prey in the larval stomachs on the second day of our study.…”

Light sensitivity in larval fishes: Implications for vertical zonation in the pelagic zone

“…However, it is unlikely that fish will feed at these threshold limits as visual resolution and prey detection distances are generally low at the limits of light sensitivity (Blaxter 1988;Utne 1997). A more likely scenario is one in which there are a number of trade-offs.…”

“…However, the proximate mechanism by which light interacts with larval behavior to influence vertical stratification remains unknown. As visual resolution and prey visibility vary with light intensity (Blaxter 1988;Utne 1997), light may act by affecting the ability of the larvae to detect and capture prey. Indeed, the combination of light intensity and prey density (ϭprey availability) may better predict lar- val fish distributions than prey density alone for some taxa (Gronkjaer and Wieland 1997).…”