DOI: 10.5061/dryad.jdfn2z3mw
title: Data from: Selectivity of invasive species suppression efforts influences control efficacy

description: Highly fecund invaders and size-selective suppression efforts often limit
 the effectiveness of invasive species control programs, as compensatory
 processes can allow suppressed populations to recover. While population
 models have long explored how demographic characteristics impact
 management feasibility, there is a growing need to evaluate how the
 selectivity of suppression efforts might impact the long-term feasibility
 of control. We use a simulation framework that integrates age-based
 selectivity to evaluate the effect of increasing the range of ages
 selected for during harvest-based invasive species control. We applied
 this approach to common carp in Utah Lake, the location of one of the
 world’s largest freshwater vertebrate species control programs, to assess
 how selectivity impacts the level of control effort necessary to achieve
 management targets. Model simulations suggest that increasing the range of
 ages effectively targeted by removal gears has the potential to
 significantly reduce the amount of effort required to reach control
 targets. We found that increasing selectivity on younger, but mature, age
 classes allowed the control program to maintain the carp population below
 the 75% biomass reduction target with only 2.5 times the maximum historic
 effort level, while further increasing juvenile selectivity conferred
 minimal benefit. Furthermore, we evaluated historic levels of harvest
 effort against both previously set management targets and theoretical
 sustainable harvest targets (MSY). The historic level of suppression
 effort was less than that required to produce MSY regardless of the
 selectivity scenario explored, suggesting the control program would be
 harvesting at a sustainable rate even if it increases the range of ages
 effectively targeted by removal gears. Controlling highly fecund invasive
 species becomes much more feasible if managers can identify an approach
 that targets all adult age classes. Explicitly considering sustainable
 harvest metrics provides a framework for evaluating a harvest control
 program’s ability to overcome density-dependent processes and achieve
 management objectives.
description: Site description Utah Lake is a large (~380
 km<sup>2</sup>), shallow (average depth 3.2 m) lake located in
 Utah County, Utah, USA. In the early 2000s, non-native carp accounted for
 over 90% of the lake’s fish biomass (SWCA, 2002) and have contributed to
 reduced water quality, altered food web dynamics (King et al., 2024), and
 pose a threat to the endemic and federally threatened June sucker
 (<em>Chasmistes liorus</em>; USFWS, 2021). Since preliminary
 reports deemed complete carp eradication infeasible due to the lake’s size
 and connectivity, managers began carp removal efforts in 2009 with a
 target to reduce carp biomass by 75% (SWCA, 2002; 2005; Walsworth et al.,
 2020). Initial reports suggested the harvest program could suppress the
 population’s reproductive potential, achieve the control target in five
 years, and decrease harvest once the program achieved the target (SWCA,
 2005; 2006). Data collection Since
 2012, standardized annual surveys using the same commercial gear applied
 during removal efforts, a 184 m long, 3 m deep commercial beach seine with
 1½-inch square mesh (<em>hereafter </em>“large mesh” seine)
 have been conducted by Utah State University, the Utah Division of
 Wildlife Resources, and Loy Fisheries. Beginning in 2020, a subset of
 hauls was conducted using a “small mesh” seine with ¾-inch mesh. While
 commercial fishers typically conducted hauls in targeted locations, each
 year researcher-led crews collected between 27 and 43 (depending on site
 accessibility) standardized seine samples from a consistent set of
 spatially stratified sites around the lake perimeter (see Landom et al.,
 2014). Field data collection was conducted under the auspices of Utah
 State University IACUC 10229 and Utah Division of Wildlife Resources
 collection permit 4COLL10240. For each seine sample in
 2020 and 2021, we recorded the total number of carp captured and randomly
 selected a subsample (up to 30 individuals) for total length and weight
 measurements. The age composition of carp caught was calculated with a
 probabilistic approach based on fitting a Von Bertalanffy growth curve to
 length-at-age data (ages estimated from the dorsal spines of a subset of
 carp) and length-frequency data (see Walsworth et al., 2020; Walsworth,
 Wallace, et al., 2023 for a full description of methods). The data
 presented in UTL_CarpSeine_DensityAge_byHaul is the resulting
 density-by-age for each seine haul from the 2020 and 2021 surveys,
 respectively.  The UTLCarp_Natage_Medians data are the
 median model outputs of abundance from the carp population model developed
 for Utah Lake. We used estimates of carp abundance-at-age from a
 statistical catch-at-age model which used standardized seine sampling
 catches, commercial fisheries effort, commercial removal data, and lake
 level measurements (see Walsworth et al., 2020 for a full model
 description, Walsworth & Landom, 2021 for an updated catchability
 component, and Walsworth, Wallace, et al., 2023 for updated abundance
 estimates). The model follows a standard age-structured framework
 (Caswell, 2001) with the addition of a Ricker stock-recruitment model
 (Ricker, 1954) and incorporates parameters for fishing effort, age-based
 gear selectivity, and lake-level effects on both catchability and
 recruitment. 
description: # Data from: Selectivity of invasive species suppression efforts
 influences control efficacy
 [https://doi.org/10.5061/dryad.jdfn2z3mw](https://doi.org/10.5061/dryad.jdfn2z3mw) ## Description of the data and file structure This dataset is associated with the accepted paper "Selectivity of invasive species suppression efforts influences control efficacy". The study evaluated the selectivity of two commercial beach seines (a 1.5 in and a 0.75 in mesh seine) used to capture invasive common carp in Utah Lake. The study found no significant difference in selectivity between the two mesh sizes, but developed a simulation modeling framework for evaluating the control efficacy of hypothetical gear selectivities. ## Experimental setup and sampling protocols To obtain the density-by-age by seine haul for the 2020 and 2021 surveys: For each seine sample in 2020 and 2021, we recorded the total number of carp captured and randomly selected a subsample (up to 30 individuals) for total length and weight measurements. The age composition of carp caught was calculated with a probabilistic approach based on fitting a Von Bertalanffy growth curve to length-at-age data (ages estimated from the dorsal spines of a subset of carp) and length-frequency data (see Walsworth et al., 2020; Walsworth, Wallace, et al., 2023 for a full description of methods).  To obtain the median model estimates of carp abundance in Utah Lake from 2009 to 2021: We used estimates of carp abundance-at-age from a statistical catch-at-age model which used standardized seine sampling catches, commercial fisheries effort, commercial removal data, and lake level measurements (see Walsworth et al., 2020 for a full model description, Walsworth & Landom, 2021 for an updated catchability component, and Walsworth, Wallace, et al., 2023 for updated abundance estimates). The model follows a standard age-structured framework (Caswell, 2001) with the addition of a Ricker stock-recruitment model (Ricker, 1954) and incorporates parameters for fishing effort, age-based gear selectivity, and lake-level effects on both catchability and recruitment. ### Files and variables #### File: UTL\_CarpSeine\_DensityAge\_byHaul\_2020.csv **Description:** Contains the density-by-age by seine haul for the standardized annual monitoring surveys conducted on Utah Lake in 2020. Every consecutive 8 lines is an independent haul.   ##### Variables * year:  the year a given haul was conducted * mesh: denotes if it was a largemesh (1.5in) or smallmesh (0.75 in) seine haul * age: the corresponding age class * density:  the catch density #### File: UTL\_CarpSeine\_DensityAge\_byHaul\_2021.csv **Description:** Contains the density-by-age by seine haul for the standardized annual monitoring surveys conducted on Utah Lake in 2021. Every consecutive 8 lines is an independent haul.  The variables are the same as the 2020 dataset.  #### File: UTLCarp\_Natage\_Medians.csv **Description:** Contains the median model estimates of carp abundance in Utah Lake from 2009 to 2021.  ##### Variables * Age: labels the age class of each row * 2009: abundance at age in 2009 * 2010: abundance at age in 2010 * 2011: abundance at age in 2011 * 2012: abundance at age in 2012 * 2013: abundance at age in 2013 * 2014: abundance at age in 2014 * 2015: abundance at age in 2015 * 2016: abundance at age in 2016 * 2017: abundance at age in 2017 * 2018: abundance at age in 2018 * 2019: abundance at age in 2019 * 2020: abundance at age in 2020 * 2021: abundance at age in 2021 ## Access information Other publicly accessible locations of the data: * [https://github.com/rfadlovi/SuppressionSelectivity](https://github.com/rfadlovi/SuppressionSelectivity)