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Comparative migration ecology of striped bass and Atlantic sturgeon in the US Southern Mid-Atlantic Bight flyway

Citation

Rothermel, Ella; O'Brien, Michael; Secor, David (2020), Comparative migration ecology of striped bass and Atlantic sturgeon in the US Southern Mid-Atlantic Bight flyway, Dryad, Dataset, https://doi.org/10.5061/dryad.6hdr7sqx3

Abstract

Seasonal migrations are key to the production and persistence of marine fish populations but movements within shelf movement corridors or, “flyways”, are poorly known. Atlantic sturgeon and striped bass, two anadromous species of concern, are known for their extensive migrations along the US Middle-Atlantic Bight. Seasonal patterns of habitat selection are well described within spawning rivers, estuaries, and shelf foraging habitats, but information on the location and timing of key coastal migrations is limited. Using a gradient-based array of acoustic telemetry receivers, we compared the seasonal incidence and movement behavior of these species in the near-shelf region of Maryland, USA. Atlantic sturgeon incidence was highest in the spring and fall and tended to be biased toward shallow regions, while striped bass had increased presence during spring and winter months and selected deeper waters. Incidence was transient (mean = ~2 d) for both species with a pattern of increased residency (> 2 d) during autumn and winter, particularly for striped bass, with many individuals exhibiting prolonged presence on the outer shelf during winter. Flyways also differed spatially between northern and southern migrations for both species and were related to temperature: striped bass were more likely to occur in cool conditions while Atlantic sturgeon preferred warmer temperatures. Observed timing and spatial distribution within the Middle-Atlantic flyway were dynamic between years and sensitive to climate variables. As shelf ecosystems come under increasing maritime development, gridded telemetry designs represent a feasible approach to provide impact responses within key marine flyways like those that occur within the US Middle-Atlantic Bight. 

Methods

All data were collected using VEMCO acoustic-release telemetry receivers deployed within the shelf region off the coast of Maryland and Delaware, USA from November 2016 to December 2018. All unique transmitter ID codes have been assigned reference numbers so that individual acoustically-tagged fish can be distinguished for analyses, but other identifiers have been removed to respect the data ownership rights of primary tagging organizations. These are the minimal required data to reproduce the results of "Comparative migration ecology of Striped Bass and Atlantic Sturgeon in the US Southern Mid-Atlantic Bight flyway". Additional details are available upon request to the author.

Residency and transit data were formulated by running original VEMCO detection data through the “RunResidenceExtraction” function in the R (R Development Core Team, 2015) V-Track software (c/o Franklin Ecolab, The University of Queensland, St Lucia, Qld, Australia). Residency events were only calculated using data collected in the focal acoustic receiver array of 24 receivers centered on the proposed Maryland Wind Energy Area (WEA). In the function, a residence event began when an acoustically-tagged fish was detected at least two times at a single receiver and was terminated when the tag was detected at a different receiver or if no new detections were recorded for 12 hours. Transit events were calculated using detections that occurred in both the Maryland acoustic receiver array and an adjacent array located of the coast of Delaware, in the proposed Delaware WEA. Only serial detections between the two arrays are reported; in the function, a transit event occurred any time an individual tag was detected sequentially between the Maryland and Delaware acoustic telemetry arrays within the span of a month.

Usage Notes

Hourly occurrence of Atlantic sturgeon and striped bass

Frequency of species detections within hours of the day were summarized from 20 acoustic telemetry receivers off Maryland, USA. Data include all dates and hours between November 16, 2016 and December 4, 2018. The first column (Time) specifies the date and hour, with the column “freq” indicating the number of individuals detected in that time period. Additional columns describe the Day, Temperature (hourly average as recorded by the receiver), Hour, Month, Year, Season, Season/year (Seasonyr), and species (Atlantic sturgeon or striped bass). All_hourly.csv

Residence events of Atlantic sturgeon and striped bass in the Maryland Wind Energy Area

These residency data were collected off Ocean City, MD November 2016 to December 2018. Columns indicate the STARTTIME and ENDTIME (yyyy-mm-dd HH:MM:SS) of the event, the Transmitter (unique number associated with a tagged individual), STATIONNAME (receiver where the residence event occurred), DURATION of the event (in hours), ENDREASON for why the event was terminated, and NUMRECS for the number of detections that comprise the residence event. The remaining columns denote the month, year, season, seasonyr (season/year) and species that correspond with each event. All_residency.csv

Transit events of Atlantic sturgeon and striped bass in the Maryland Wind Energy Area

These transit data were collected off the coast of Maryland and Delaware, USA November 2016 to December 2018. Columns indicate the STARTTIME and ENDTIME (yyyy-mm-dd HH:MM:SS) of the event, Transmitter (unique number associated with a tagged individual), STATIONNAME1 and STATIONNAME2 (receivers where the first and second detections occurred, respectively) DURATION of the event (in seconds), DISTANCE (between receivers, in meters), and ROM (rate of movement, in m/s). Other columns of note include the array in which each detection occurred (Array1, Array2), the direction of transit along the coast (Direction), and the rate of transit in km/h. Species and individual characteristics used for other analyses are also indicated (Sex, Weight, TL). All_transit.csv

Frequency of individual striped bass detections offshore of Maryland, USA

These detection data for acoustically-tagged striped bass were collected using a primary array of 20 acoustic-release telemetry receivers deployed off the coast of Ocean City, Maryland, USA from November 2016 to December 2018. All potential days and sites for species detection are included. Relevant columns denote Site (acoustic receiver ID), Day (yyyy-mm-dd), transmitter (unique tag identification number), and freq (number of detections). NA values occur in the transmitter column when no individuals were detected. Temperature, Noise, Lat, Long, Array, and Depth_m are also included for reference information. Temperature and noise values are based on daily averages recorded in-situ by receivers at each site. Individual_detections_bass.csv

Frequency of individual Atlantic sturgeon detections offshore of Maryland, USA

These detection data for acoustically-tagged Atlantic sturgeon were collected using a primary array of 20 acoustic-release telemetry receivers deployed off the coast of Ocean City, Maryland, USA from November 2016 to December 2018. All potential days and sites for species detection are included. Relevant columns denote Site (acoustic receiver ID), Day (yyyy-mm-dd), transmitter (unique tag identification number), and freq (number of detections). NA values occur in the transmitter column when no individuals were detected. Temperature, Noise, Lat, Long, Array, and Depth_m are also included for reference information. Temperature and noise values are based on daily averages recorded in-situ by receivers at each site. Individual_detections_sturg.csv

Daily, receiver-based presence/absence of striped bass and sturgeon for quotient analysis

These data were collected using a primary array of 20 acoustic telemetry receivers offshore of Maryland, USA from November 2016 to December 2018. The file contains a column for the Day (yyyy-mm-dd), Site (receiver ID), Temperature, freq (presence/absence of acoustically-tagged individuals), and Season. Temperature values are based on daily averages recorded at each site. There are separate files for each species. Quotient_analysis_bass.csv, Quotient_analysis_sturg.csv

Funding

Bureau of Ocean Energy Management, Award: M16AC00008