Live fish highway: Uncovering the pathways that move millions of minnows across the United States
Data files
Apr 14, 2026 version files 2.46 MB
Abstract
The long-distance transport of live baitfish represents a significant yet under-quantified pathway for the spread of aquatic invasive species and pathogens, posing a substantial threat to freshwater ecosystems and local economies across the United States. To address the lack of high-quality, quantitative data necessary for rigorous risk assessment and biosecurity policy, this dataset provides a comprehensive record of interstate baitfish trade flows between 2022 and 2024, synthesized from Freedom of Information (FOI) requests submitted to 58 government agencies across 43 states. The dataset captures the movement of 39.3 million live baitfish and an additional 746 transport events where specific quantities were not recorded, with data disaggregated by species and geographic origin-destination pairs. While the records reflect inherent variability in state government record-keeping, resulting in some data gaps, the dataset offers high reuse potential for researchers and policymakers to identify high-traffic trade routes, model pathogen dispersal, and strengthen environmental biosecurity frameworks. All data were obtained through public records requests and represent official government documentation of trade activities.
Dataset DOI: 10.5061/dryad.34tmpg4zg
Description of the data and file structure
This spreadsheet contains the data obtained from open records request relating to trade flows of live baitfish across the United States, extracted and assembled into a structured format more amenable to statistical analysis.
For each of those 58 state government departments, we lodged a freedom-of-information/open records request with that department under the corresponding state's freedom-of-information/open records legislation. The request letter asked for copies of the completed license application documents corresponding to all licenses granted for the import of live finfish into the state during calendar years 2022, 2023, and 2024, as well as additional documents held by the department that contains details of species and quantity of live fish imported into the state during that period. We also followed up several times with the handful of departments that did not promptly acknowledge the request.
Of our 58 freedom-of-information/open records requests across 43 states, 49 requests across 39 states were fulfilled. Of these, 31 provided documents, yielding a total of 2.3 GB of original documents (PDF, XLS, and DOCX file formats). In 16 states, departments either confirmed that the requested records did not exist or provided records that exclusively related to non-bait purposes (Table 1). Six requests were rejected for administrative reasons (one for each of Alabama and Kentucky and two for each of Arkansas and Tennessee), and a further three requests were ignored even after multiple follow-ups (one for each of Arizona, North Carolina, and Wisconsin).
The final dataset contained 7,863 data points.
The main file "Trade_flows_data_obtained_from_FOIA_records_data.csv" contains the information useful for future analysis. Each row contains a record of a trade flow into a state from another state. If a record describes multiple species (e.g. a shipment that contains several different species of baitfish), then this record corresponds to multiple trade flows, and hence is represented by multiple rows in this spreadsheet. In this file, the value "n/a" represents no data for that row, or a blank cell.
The other file "Trade_flows_data_obtained_from_FOIA_records_departments.csv" provides additional metadata. It describes the status of open records request lodged with departments during our research project, and some key facts about those departments.
Files and variables
File: Trade_flows_data_obtained_from_FOIA_records_data.csv
Description:
Variables
| Column | Description |
| state_data | The state to which the data relates (i.e., the state into which this trade flow is coming), almost always the same as the state from which the record or data was obtained. State name is expressed as the full state name. |
| record_file_name | The path to the file that contains this record or evidence, expressed relative to the directory of records obtained. In the case of records that are available publicly (specifically, the public lists of bait suppliers that are posted by some states), this is instead the URL of the persistent link (on Internet Archive) to that page. |
| record_id_in_file | If more than one record exists in record_file_name (e.g. a spreadsheet of license holders or a PDF of multiple scanned documents), a string that uniquely identifies the row within the file. This will depend on the file itself and will differ across files, but will usually be something like a row ID, a page number, or a license number. |
| department_name | Name of the government department that provided the record. |
| data_type | One of three options: Is the data quantitative, qualitative, or a confirmation that the government does not have this data? (expressed as "quantitative", "qualitative", and "non-existent" respectively) Qualitative data records only the existence of a trade flow, e.g. somebody in State A who is licensed to ship minnows into State B but with no evidence of quantity. Quantitative data records the existence of a trade flow *and* a measure of the magnitude, e.g. weight or dollar value of minnows. |
| record_year | The year to which the record corresponds (i.e. the year of the *trade flow*, not necessarily the year in which the data was published) |
| facility_source | The location or business from which the trade flow has come |
| state_source | The state from which the trade flow has come, i.e. state of origin. If this is not reported directly by the record, then it can be determined based on facility_source (e.g. Googling a business name and seeing what state it is in). State name is expressed as the full state name. |
| fish_quantity | If available, the quantity of fish |
| fish_quantity_unit | The unit in which fish_quantity is expressed |
| fish_species_original | If available, the species of the fish, as expressed in the original record (preserving common names). This will be automatically translated into the binomial (taxonomic) species name during data analysis. |
| confidence_bait | Our confidence, based on the information provided in the record, that this row represents fish used for bait. One of: likely, possible, unlikely, insufficient information |
| confidence_bait_reasoning | Brief notes as to the reasoning for the row's assigned confidence_bait category |
Code/software
Any software that can open a CSV text file, e.g., Microsoft Excel or OpenOffice Calc