Are individual differences in fish movement related to angling vulnerability? Whole-lake experiments using high-resolution acoustic telemetry

Date: 
Thursday 15 November 2018 - 14:00 to 15:00
Location: 
NOC Southampton - Node Room (074/02) (Waterfront Campus).
Speaker: 
Dr Chris Monk, IGB Berlin

Passive  fishing  gears,  such  as  hook-and-line  angling,  are  expected  to  selectively  capture  fish  of  certain  behavioural  types  because  by  definition   passive   gears   exploit   fish   behaviour.    Behaviours    increasing    angler  encounters  (e.g.,  activity  or  activity  space  size)  and  behaviours  promoting  bites  (e.g.,  boldness  or  aggression) are good candidates for angling  induced  behavioural  selection,  but  the  importance  of  specific  behaviours  is  likely  a  function  of  a  given species‘ foraging mode in light of the lures and baits by which it is targeted.   Further,   fishing   induced   behavioural selection is expected to be modified by the searching strategies and techniques of  fishers.  Our  aim  was  to  comprehensively  tease  apart  the  role  of  fish  and  fisher  behaviour  as  it  relates  to  fish  vulnerability  in  the  wild  by  analyzing  long-term  acoustic  tracking  data  at  a  whole  lake-scale  collected  from  both   piscivorous   and   omnivorous   fishes, viz.: perch (Perca fluviatilis), carp  (Cyprinus  carpio),  tench  (Tinca tinca) and pike (Esox lucius). All species were experimentally angled. Direct  encounters  with  anglers  and  related behaviours including activity, activity space size, or distance to the shore were unrelated to angling vulnerability  in  carp,  tench  and  perch.  Perch  preferring  a  certain  habitat  (north  lake  shore)  were,  however,  preferentially captured independent of  angler  encounters.  By  contrast,  activity  space  size  was a  significant  driver of vulnerability in pike, supporting the idea that the relationship between fish behaviour and vulnerability  is  species  specific.    All  behaviours  we  assessed  were  repeatable  in the wild, such that ultimately our data  suggest  angling-induced  selection  targets  different  behaviours  in  different species.     

Seminar category: 
POETS Corner