DOI: 10.5061/dryad.gqnk98sz3
title: Data from: The combined effects of multiple invasive species on persistence of imperiled Pahrump Poolfish

description: Many ecosystems have been invaded by more than one non-native species, but
 research evaluating the combined effects of multiple invasive species has
 been limited. In the southwest USA, many aquatic systems have been invaded
 by multiple species such as non-native crayfish and non-native fishes. We
 used experimental mesocosms to test individual and combined effects of
 invasive Red Swamp Crayfish, Procambarus clarkii, and Western
 Mosquitofish, Gambusia affinis, on endangered Pahrump Poolfish,
 Empetrichthys latos. We found that crayfish alone reduced adult poolfish
 survival; however, crayfish by themselves had moderate but non-significant
 impacts on the production of poolfish juveniles. Mosquitofish had no
 effect on the survival of poolfish adults, but significantly reduced
 recruitment of juveniles. When both crayfish and mosquitofish were
 present, both adult survival and juvenile production were significantly
 decreased. These findings were consistent with the recent decline of a
 wild poolfish population from over 10,000 fish to less than 1,000 poolfish
 following the establishment of crayfish and mosquitofish. This study
 demonstrates that conservation management of the Pahrump Poolfish must
 have active management and removal of invasive species, otherwise
 extirpation and eventually extinction will likely occur. This study also
 provides an example of the compounding effects of multiple invasive
 species.
description: Western Mosquitofish were obtained from Sutter-Yuba Mosquito and
 Vector Control district in Yuba City, CA. Poolfish used in this experiment
 included a mixture of wild poolfish and lab-reared poolfish. The wild
 poolfish were collected from on 13 June 2017 from Shoshone Stock Pond
 (White Pine County, NV) while the lab-reared poolfish were descendants
 from poolfish originally collected in 2014 from Spring Mountain Ranch
 State Park, Clark County [31]. Red Swamp Crayfish were sourced from
 Carolina Biological suppliers Burlington, NC.  Three
 fish communities were used in this experiment forming a single block
 within a randomized block design. Each of seven blocks contained a total
 of three mesocosms including the following treatments: I.) allopatric
 poolfish, II.) poolfish sympatric with crayfish, and III.) poolfish
 sympatric with both mosquitofish and crayfish. We did not include a
 poolfish + mosquitofish treatment because of the limited number of
 poolfish available for this experiment.  Further, three previous
 experiments consistently showed that mosquitofish effectively eliminated
 the production of juvenile poolfish. Each block of
 three tanks was replicated seven times for a total of 21 experimental
 tanks, arranged in a linear sequence. All 21 tanks received seven adult
 poolfish of indeterminate sex and of indeterminate population of origin
 (Shoshone Stock Pond 2017 or Spring Mountain Ranch 2014). Four individual
 crayfish were introduced into two randomly selected mesocosms per block.
 One of the two crayfish mesocosms within each block was randomly selected
 to receive mosquitofish, including five gravid females and two males.
 Crayfish density was maintained by replacing any crayfish that
 died. All mesocosms were provided with reclaimed PVC
 vinyl Fishiding® structures to simulate aquatic plants and to provide
 spatial structure along with ~57 L of river rock. Supplemental food was
 provided every day to each tank at rates of ~2-3% of total fish biomass,
 while crayfish were fed twice weekly. Food consisted of Tetra tropical
 flake, and Aquatic Arts (Fish, Inverts, and Aquatic Plant) sinking
 pellets. Water quality was assessed weekly for ammonia and nitrates. All
 tanks were checked daily for mortalities, and to ensure air flow was
 constant from air stones. After ten-weeks, the tanks were drained, and
 juveniles and adults were counted. Data were analyzed
 using JMP Pro 17® software. We tested for treatment effects on adult
 survival, juvenile production, and the number of juveniles produced per
 surviving adult poolfish. We used ANOVA followed by Tukey HSD while
 maintaining experimental-wise alpha at 0.05. For each test, block was not
 significant and was eliminated from the final model. Non-parametric
 analyses produced the same significance levels among treatments for all
 tests, but here we report the parametric ANOVA results.
description: # Crayfish and mosquitofish impacts on experimental poolfish populations
 This readme file was generated on 2024/12/20 by Craig Stockwell ## GENERAL
 INFORMATION Title of Dataset: Author/Principal Investigator Information
 Name: Brandon Paulson ORCID:
 [https://orcid.org/0000-0002-4635-1485](https://orcid.org/0000-0002-4635-1485) Institution: North Dakota State University Address: Biological Sciences, Stevens Hall 201, NDSU Box 6050, Fargo, ND 58108 Email: [brandonpaulson28@gmail.com](mailto:brandonpaulson28@gmail.com) Author/Associate or Co-investigator Information Name: Craig Alan Stockwell ORCID: [https://orcid.org/0000-0001-7882-8674](https://orcid.org/0000-0001-7882-8674) Institution: North Dakota State University Address: Biological Sciences, Stevens Hall 201, NDSU Box 6050, Fargo, ND 58108 Email: [Craig.Stockwell@ndsu.edu](mailto:Craig.Stockwell@ndsu.edu) Date of data collection: Experiment with Poolfish_Crayfish and Mosquitofish: 2017-06-01 to 2018-08-10 Geographic location of data collection: Experiment with Poolfish_Crayfish and Mosquitofish conducted at North Dakota State University, Fargo, ND USA Information about funding sources that supported the collection of the data: Desert Fishes Council Conservation Award; ## SHARING/ACCESS INFORMATION Licenses/restrictions placed on the data: NA Links to publications that cite or use the data: Links to other publicly accessible locations of the data: NA Links/relationships to ancillary data sets: NA Was data derived from another source? No If yes, list source(s): Recommended citation for this dataset: Paulson and Stockwell (2025). Data from: The combined effects of multiple invasive species on persistence of imperiled Pahrump Poolfish. Dryad, Dataset, [https://doi.org/10.5061/dryad.gqnk98sz3](https://doi.org/10.5061/dryad.gqnk98sz3) ## DATA & FILE OVERVIEW File List: File # 1 Paulson and Stockwell Pahrump poolfish mesocosm experiment This file has the mesocosm data for poolfish populations that were maintained as follows: a) Poolfish-Allopatry; b) Poolfish & Crayfish; c) Poolfish & Crayfish & Mosquitofish. The data includes the number of poolfish adults stocked, the number of poolfish adults that survived, the number of poolfish juveniles produced. The complete data set of 21 mesocosm trials is included. Relationship between files, if important: NA Additional related data collected that was not included in the current data package: NA Are there multiple versions of the dataset? No If yes, name of file(s) that was updated: Why was the file updated? When was the file updated? ### DATA-SPECIFIC INFORMATION FOR: Paulson and Stockwell Pahrump poolfish mesocosm experiment Number of variables: 10 Number of cases/rows: 21 **Variable List:** * Block: 7 blocks of 3 treatment tanks each * Tank: Tank Idenfication * Treatment: Three treatsments including a) Poolfish; b) Poolish & Crayfish and c) Poolfish & Crayfish & Mosquitofish * Poolfish Stocked: The number of adult poolfish stocked * Surviving Poolfish Adults: The number of adult poolfish alive at the end of the experiment * Poolfish Adult Survival: Percentage of adults that survived to the end of the experiment. * Poolfish Juvenile Number: Number of poolfish juveniles at end of the experiment. * Total Poolfish Juvenile Mass (g): The total mass of all surviving juveniles at the end of the experiment. * Relative Recruitment: Number of juveniles produced per surviving adult at the end of the experiment. * Mosquitofish juveniles: Number of mosquitofish juveniles at end of experiment for tanks with mosquitofish. Missing data codes (blank cells): NA Specialized formats or other abbreviations used: NA Notes: NA