Gillnet catchability of brown trout Salmo trutta is highly dependent on fish size and capture site
Main Article Content
Abstract
Use of experimental gillnet fleets is common both in scientific studies of fish populations and in fish
sampling for management purposes. Fish catchability may vary considerably with fish and gillnet mesh
size, and catches obtained by gillnet fleets composed of nets with different mesh sizes may give length
and age distributions that deviate considerably from the length and age structure of the population.
We have estimated the absolute catchability of allopatric brown trout (Salmo trutta) in the littoral and
pelagic habitat of a small lake based on a mark-recapture experiment. The brown trout catchability
varied considerably both with fish size and habitat type, probably due to a size-related variation in
swimming distance per time unit and a size-related use of the different lentic habitats. The sampling
bias in experimental gillnet fishing may be reduced by operating the gillnet fleets in all possible lentic
habitats and most fundamentally, by use of catchability data obtained from populations with ‘known’
length and age structures. By reducing this sampling bias, more realistic estimations of the age and
length distribution for a given population will be possible.
Downloads
Article Details
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).