The vulnerability of juvenile signal crayfish to perch and eel predation

• Published in: Freshwater Biology
• Main Authors: BLAKE, M.A., HART, P.J.B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1995
• Subjects: Anguilla anguilla
• Online Access: http://dx.doi.org/10.1111/j.1365-2427.1995.tb01164.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-2427.1995.tb01164.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2427.1995.tb01164.x

SUMMARY 1. We conducted laboratory experiments to determine how juvenile signal crayfish ( Pacifastacus leniusculus ) responded to two predators with different foraging behaviours (European eel Anguilla anguilla and European perch Perca fluviatilis ), and whether these responses affected their vulnerability. 2. By accelerating a model predator towards crayfish which had been temporarily blinded, we assessed whether crayfish had to see predators in order to escape. Blind crayfish escaped later than did sighted crayfish attacked in the same manner. 3. Both eels and perch elicited similar evasive behaviour when approaching and attacking sighted crayfish. Crayfish usually escaped these initial attacks but perch chased and caught more crayfish than did eels. 4. In a third experiment, perch preyed more rapidly on a population of crayfish than did eels. By the end of the experiment, however, crayfish survival rates were similar in response to eel and perch predation. 5. Our results show that crayfish are well adapted to evade predatory attacks based on rapid responses to both visual and/or mechanical stimuli. The results also suggest that behaviourally, crayfish are more vulnerable to attacks by perch than by eels. We discuss these findings in relation to other factors that affect the vulnerability of crayfish to these predators.