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Spatial structuring within a reservoir fish population: implications for management

Marine and Freshwater Research

By:
, ORCID iD , and
https://doi.org/10.1071/MF14085

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Abstract

Spatial structuring in reservoir fish populations can exist because of environmental gradients, species-specific behaviour, or even localised fishing effort. The present study investigated whether white crappie exhibited evidence of improved population structure where the northern more productive half of a lake is closed to fishing to provide waterfowl hunting opportunities. Population response to angling was modelled for each substock of white crappie (north (protected) and south (unprotected) areas), the entire lake (single-stock model) and by combining simulations of the two independent substock models (additive model). White crappie in the protected area were more abundant, consisting of larger, older individuals, and exhibited a lower total annual mortality rate than in the unprotected area. Population modelling found that fishing mortality rates between 0.1 and 0.3 resulted in sustainable populations (spawning potential ratios (SPR) >0.30). The population in the unprotected area appeared to be more resilient (SPR > 0.30) at the higher fishing intensities (0.35–0.55). Considered additively, the whole-lake fishery appeared more resilient than when modelled as a single-panmictic stock. These results provided evidence of spatial structuring in reservoir fish populations, and we recommend model assessments used to guide management decisions should consider those spatial differences in other populations where they exist.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Spatial structuring within a reservoir fish population: implications for management
Series title:
Marine and Freshwater Research
DOI:
10.1071/MF14085
Volume:
66
Issue:
3
Year Published:
2014
Language:
English
Publisher:
CSIRO Publishing
Contributing office(s):
Coop Res Unit Atlanta
Description:
11 p.
First page:
202
Last page:
212
Online Only (Y/N):
N
Additional Online Files (Y/N):
N