DOI: 10.5061/dryad.8w9ghx3j8
title: Data for: Performance of a high-frequency (180 kHz) acoustic array for tracking juvenile Pacific salmon in the coastal ocean

description: Background Acoustic telemetry is now a key research tool used to quantify
 juvenile salmon survival, but transmitter size has limited past studies to
 larger smolts (&gt;130 mm fork length). New, smaller, higher-frequency
 transmitters (“tags”) allow studies on a larger fraction of the smolt size
 spectrum (&gt;95 mm); however, detection range and study duration are
 also reduced, introducing new challenges. The potential cost implications
 are not trivial. With these new transmitters in mind, we designed,
 deployed, and tested the performance of a dual-frequency receiver array
 design in the Discovery Islands region of British Columbia, Canada. We
 double-tagged 50 juvenile steelhead (Oncorhynchus mykiss) with large 69
 kHz tags (VEMCO model V9-1H) and small 180 kHz tags (model V4-1H). The
 more powerful 69 kHz tags were used to determine fish presence in order to
 estimate the detection efficiency (DE) of the 180 kHz tags. We then
 compared the standard error of the survival estimate produced from the
 tracking data using the two tag types which has important implications for
 array performance and hypothesis testing in the sea. Results Perfect
 detection of the 69 kHz tags allowed us to determine the DE of the 180 kHz
 tags. Although the 180 kHz tags began to expire during the study, the
 estimated DE was acceptable at 76% (SE = 9%) when we include single
 detections. However, confidence intervals on steelhead survival (64%) were
 1.5x larger for the 180 kHz tags (47-85% vs. 51-77% for 69 kHz) because of
 the reduced DE. Conclusions The array design performed well; however,
 single detections of the 180 kHz tags indicates that under slightly
 different circumstances the DE could have been compromised, emphasizing
 the need to carefully consider the interaction of animal migration
 characteristics, study design, and tag programming when designing
 telemetry arrays. To increase DE and improve the precision of 180
 kHz-based survival estimates presented here requires either an increase in
 receiver density, an increase in tag sample size (and modified transmitter
 programming), or both. The optimal solution depends on transmitter costs,
 array infrastructure costs, annual maintenance costs, and array use (i.e.,
 contributors). Importantly, the use of smaller tags reduces potential tag
 burden effects and allows early marine migration studies to be extended to
 Pacific salmon populations that have been previously impossible to study.
description: We
 double-tagged 50 juvenile steelhead (<i>Oncorhynchus
 mykiss</i>) with large 69 kHz tags (VEMCO model V9-1H) and small 180
 kHz tags (model V4-1H). The more powerful 69 kHz tags were used to
 determine fish presence in order to estimate the detection efficiency (DE)
 of the 180 kHz tags. We then compared the standard error of the survival
 estimate produced from the tracking data using the two tag
 types. 
description: File list: Tags_metadata.csv<br>
 Detections_data.csv<br> Detection_efficiency_69kHz.r<br>
 Detection_efficiency_180kHz.r<br> Count_detections.r<br>
 Survival_using_180kHz_tags.r<br>
 generate_capture_histories.r<br> util.r
 Instructions: It is simplest to put all files
 into a single working directory for all R scripts to work. In addition to
 the packages listed at the top of the R scripts, Program Mark must be
 installed to run Survival_using_180kHz_tags.r
 (http://www.phidot.org/software/mark/rmark/). See publication for detailed
 analytical methods. File descriptions:
 Tags_metadata.csv-- each row represents a steelhead smolt from
 Seymour River hatchery that was acoustic-tagged in 2015.
 fish_id=concatenation of the 69 kHz and 180 kHz codes transmitted by the
 acoustic tags implanted into this inidividual; code_label_69 and
 tag_id_69=identification codes transmitted by the V9 69 kHz tags;
 code_label_180 and tag_id_180=identification codes transmitted by the V4
 180 kHz tags; fl=fork length in mm; weight=fish weight in air in g;
 treatment_type=not populated; utc_release_datetime=date and time the
 tagged fish were released in universal coordinated time yyyy-dd-mm
 hh:mm:ss. Detections_data.csv-- each row represents a
 recorded transmission from an acoustic tag implanted into a steelhead
 smolt from Seymour River hatchery in 2015. tag_id and code_label= unique
 identification  codes transmitted by the tag; receiver_sn= serial number
 of the receiver that recorded the transmission; detection_datetime= date
 and time the detection was recorded in universal coordinated time
 yyyy-mm-dd hh:mm:ss; subarray= name for the group of receivers deployed at
 the same general location (see Figure 2 in publication for map);
 subsubarray= adds detail to subarray name; position= for subarrays
 deployed in lines, this is a numerical position from east to west or south
 to north; kintama_nickname= a shortened name the receiver subarray and
 position; final= direction of migration; tag_type= tag implated (V9-1H or
 V4-1H); utc_release_datetime=date and time the tagged fish were released
 in universal coordinated time yyyy-dd-mm hh:mm:ss; tag_id2= unique
 identification  code transmitted by the other tag implanted into this
 individual; fish_id=concatenation of the 69 kHz and 180 kHz codes
 transmitted by the acoustic tags implanted into this
 inidividual. Detection_efficiency_69kHz.r-- R script
 that calculates the detection efficiency of the 69 kHz V9 tags implanted
 into steelhead smolts from Seymour River hatchery in 2015.
 Detection_efficiency_180kHz.r-- R script that calculates the
 detection efficiency of the 180 kHz V4 tags implanted into steelhead
 smolts from Seymour River hatchery in 2015.
 Count_detections.r-- R script that counts the number of
 detections of each tag recorded at the Discovery Islands subarray and its
 component south and north subsubarrays.
 Survival_using_180kHz_tags.r-- R script that provides empicial
 estimates of the conficence intervals on the survival estimates that would
 have been obtained had fish been tagged only with V4 180 kHz tags and had
 exited the study area prior to tag expiry (i.e. as in a regular
 study). generate_capture_histories.r-- R function that
 generates a simulated frequency distribution for all possible capture
 histories and returns a data frame that can be passed to RMark.
 util.r-- R function called from
 generate_capture_histories.r