The effects of turbidity, prey density and environmental complexity on the feeding of juvenile Murray codMaccullochella peelii

Abstract

Juvenile Murray cod Maccullochella peelii exhibited a type II functional response while preying on blackworms Lumbriculus variegatus, and the parameters of the type II model did not differ significantly between clear (0 NTU) and turbid (150 NTU) treatments. Further experiments showed that vision may not be necessary for prey detection and capture by juvenile M. peelii; consumption of inanimate prey was not significantly different between light and dark (<1 × 10(-4) µE m(-2) s(-1)) trials. These results imply that the sensory physiology of M. peelii is well adapted to a turbid visual environment. In addition, habitat complexity increased the food consumption rate of juvenile M. peelii, perhaps by relaxing innate predator avoidance behaviours that depress foraging in more open environments.

Physiological Trade-Offs Along a Fast-Slow Lifestyle Continuum in Fishes: What Do They Tell Us about Resistance and Resilience to Hypoxia?

“…fluviatilis were transported to the laboratory in 20 L buckets at low densities (5 per bucket) to minimise stress while in transit (< 1 h). Further details concerning fish collection and accommodation can be found in Dwyer et al [63] and Allen-Ankins et al [65]. Water temperature for accommodation and all experiments was fixed at 25°C, a temperature commonly experienced by these fishes in the wild during spring-summer-autumn [60].…”

Environmental enrichment for fish in captive environments: effects of physical structures and substrates

“…Complexity may also affect foraging rate, either negatively due to decreased activity from sheltering, lowered manoeuvrability or reduced prey detectability (reviewed in Gotceitas and Colgan ), or positively due to modification of innate predator avoidance behaviours in protected complex environments (Allen‐Ankins et al . ) and accumulation of prey organisms (Gustafsson et al . ).…”

“…Increased complexity also creates refuges for subordinate individuals (H€ ojesj€ o et al 2004). Complexity may also affect foraging rate, either negatively due to decreased activity from sheltering, lowered manoeuvrability or reduced prey detectability (reviewed in Gotceitas and Colgan 1989), or positively due to modification of innate predator avoidance behaviours in protected complex environments (Allen-Ankins et al 2012) and accumulation of prey organisms (Gustafsson et al 2014). Generally, negative effects tend to be more common (Gotceitas and Colgan 1989).…”

Structural complexity and turbidity do not interact to influence predation rate and prey selectivity by a small visually feeding fish

“…In addition, with increased turbidity, prey reduce (or do not show) antipredator behaviour because of the availability of the visual refuge Carter et al 2010). In this way, the true effects of structural complexity and turbidity on predation and prey selectivity may be influenced by prey characteristics, such as mobility (Banks et al 2000), body size (Dörner and Wagner 2003), body colour (Jönsson et al 2011) and abundance (Allen-Ankins et al 2012). The balance between prey preference and vulnerability could determine the foraging costs to the predator (Griffiths 1980), and predation rates are not exclusively defined by environmental conditions but, rather, are affected by a combination of prey characteristics and environmental conditions.…”