Casting light and fishing lures on long-term coarse woody habitat effects

Abstract

Coarse woody habitat (CWH) modifications to aquatic ecosystems are often a short-term plan for management goals. Positive CWH effects can often be a draw for fish in the area to utilize it for feeding, reproduction, and survival. Though this woody debris can start to degrade and move, further altering the ecosystem, the long-term effects of these modifications are often not thoroughly studied. Following a CWH study (Sass, 2004-2012) on Camp Lake in Vilas County, Wisconsin, there was little to no follow-up research on the system. Half of Camp Lake was subject to a CWH addition (treatment basin; 140 log/km) while the other half was left untouched (reference basin; 40 log/km). Our study focused on the long-term effects following the modification, would the CWH still provide enough essential benefits for the largemouth bass (Micropterus salmoides) that it would impact their movements and habitat usage? In utilizing hook-and-line fishing and PIT tags over 3 months, there were 154 tagged largemouth bass, and only 1 moved between the basins. In addition, a CWH survey was conducted and found that the basins’ CWH density had flipped over the last 15 years with the treatment having 85 log/km and the reference having 103 log/km. The results indicate that water systems are extremely dynamic and subject to substantial long-term changes. However, the largemouth bass have also been able to adapt to those changing habitat conditions. Unfortunately, increasing lakeshore residential development and the removal of CWH from lakes may remove the possibility of fish moving and adapting to long-term habitat changes. So, in making CWH management decisions, both short-term and long-term effects should be taken into consideration

Full text

Casting Light and Fishing Lures on
Long-Term Coarse Woody Habitat Effects
RESULTS
INTRODUCTION
METHODS
ACKNOWLEDGEMENTS
DISCUSSION
CONCLUSIONS
Emma Millsap, Quinn Smith, Joe Mrnak, Greg Sass
QUESTION
2004
Reference Basin: 40 logs/km
Treatment Basin: 141 logs/km
2023
Reference Basin: 103 logs/km
Treatment Basin: 85 logs/km
Reference Basin
Treatment Basin
Fish Movement
CWH Changes
154 Fish Marked
9 Fish Recaptured
1 Fish moved from Treatment into Reference Basin
Movement: Constant
Encounter: State Based
•Camp Lake, Vilas
County WI
•Mark/Recapture
•Hook-and-Line
Sampling
•PIT Tags/Fin Clips
•Coarse Woody
Habitat Survey
•June-August 2023
1. Ahrenstorff, Tyler & Sass, Greg & Helmus, Matthew. (2009). The influence of littoral zone coarse woody habitat on home range size, spatial
distribution, and feeding ecology of Largemouth Bass (Micropterus salmoides). Hydrobiologia. 623. 223-233. 10.1007/s10750-008-9660-1.
2. Dassow, Colin & Ross, Alelexander & Jensen, Olaf & Sass, Greg & Van Poorten, Brett & Solomon, Christopher & Jones, Stuart. (2019).
Experimental demonstration of catch hyperstability from habitat aggregation, not effort sorting, in a recreational fishery. Canadian Journal
of Fisheries and Aquatic Sciences. 77. 762-769. 10.1139/cjfas-2019-0245.
3. Sass, Greg & Carpenter, Stephen & Gaeta, Jereme & Kitchell, James & Ahrenstorff, Tyler. (2012). Whole-lake addition of coarse woody
habitat: Response of fish populations. Aquatic Sciences. 74. 255-266. 10.1007/s00027-011-0219-2.
4. Sass, Greg & Kitchell, James & Carpenter, Stephen & Hrabik, Thomas & Marburg, Anna & Turner, Monica. (2006). Fish Community and Food
Web Responses to a Whole-lake Removal of Coarse Woody Habitat. Fisheries. 31. 321-330. 10.1577/1548-
8446(2006)31[321:FCAFWR]2.0.CO;2.
5. Theis, Sebastian, Jonathan LW Ruppert, and Mark S. Poesch. "Coarse woody habitat use by local fish species and structural integrity of
enhancements over time in a shallow northern boreal lake assessed in a Bayesian modelling approach." Ecological Solutions and Evidence
4.2 (2023): e12200.
REFERENCES
Huge thank you to everyone else who helped on this
project in a multitude of ways; my co-authors, Jack
Abel, Chris Rounds, Max Wilkinson, Kayla Witliff, Elise
Bass, the Juday Family, and Trout Lake Station Staff
•Program MARK
•Probabilities of Interest
1. Movement
2. Encounter
•Constant, State, or
State and Time Based
•‘Best Fit’ Model
selected on AICc
•LMB movement was less and in
opposite direction of hypothesis (1 fish)
•Log densities of basins reversed over
the course of 20 years
•Degradation, ice/flooding/drought
dynamics, human intervention
•Much more likely to encounter a fish in
reference basin
•Fish density, limnological factors, etc.
•Lakeshore residential development
removes available CWH both in water
and shoreline
•Removes the chance for CWH inputs
into the waterbody from
storm/flooding/natural events in the
long-term
•Coarse woody habitat (CWH) additions
provide many ecosystem services to fish
species
•Over time, CWH starts to degrade and move,
once again changing the system
•Lakeshore residential development can
remove vital CWH and its long-term benefits
for fish populations
•2004: Tagged logs added as CWH into
treatment basin shoreline
•2008-2012: Found very little largemouth bass
movement + smaller home ranges in CWH
•Hypothesized to see fish movement from
reference to treatment basin
What are the long-term effects of
coarse woody habitat additions
on largemouth bass (LMB)
movements and habitat use?
Largemouth bass
(Micropterus salmoides)
Lakes are extremely dynamic in
the long-term, though
largemouth bass have been
able to adapt to changing
habitat structure.
Some logs tagged in 2004 and put into treatment
basin were found within the reference basin in 2023
Tagged
logs
Probability of
Movement: 1.5%
Probability of
Encounter:
0.041%
Probability of
Encounter:
0.38%