How do fishes find the shore? Evidence for orientation to bathymetry from the non-homing sea lamprey

Please see manuscript. To address the reviewers, our abstract is slightly longer than the word limit. Orientation to a shoreline is the critical first step for aquatic organisms that navigate to coastal waters, estuaries, and rivers to feed or reproduce. Most study of animal migration has focused on homing-based navigation while non-homing navigation is poorly understood. We quantified the navigation behavior of sea lamprey during their non-homing return migration to a coastline in the Laurentian Great Lakes. Acoustically-tagged sea lamprey were displaced 3.3 km from shore into the center of an acoustic listening array that provided high resolution (30s intervals,The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Data from: A simple, cost-effective emitter for controlled release of fish pheromones: development, testing, and application to management of the invasive sea lamprey

Semiochemicals that elicit species-specific attraction or repulsion have proven useful in the management of terrestrial pests and hold considerable promise for control of nuisance aquatic species, particularly invasive fishes. Because aquatic ecosystems are typically large and open, use of a semiochemical to control a spatially dispersed invader will require the development of a cost-effective emitter that is easy to produce, environmentally benign, inexpensive, and controls the release of the semiochemical without altering its structure. We examined the release properties of five polymers, and chose polyethylene glycol (PEG) as the best alternative. In a series of laboratory and field experiments, we examined the response of the invasive sea lamprey to PEG, and to a partial sex pheromone emitted from PEG that has proven effective as a trap bait to capture migrating sea lamprey prior to spawning. Our findings confirm that the sea lamprey does not behaviorally respond to PEG, and that the attractant response to the pheromone component was conserved when emitted from PEG. Further, we deployed the pheromone-PEG emitters as trap bait during typical control operations in three Great Lakes tributaries, observing similar improvements in trap performance when compared to a previous study using mechanically pumped liquid pheromone. Finally, the polymer emitters tended to dissolve unevenly in high flow conditions. We demonstrate that housing the emitter stabilizes the dissolution rate at high water velocity. We conclude the performance characteristics of PEG emitters to achieve controlled-release of a semiochemical are sufficient to recommend its use in conservation and management activities related to native and invasive aquatic organisms

What is the animal doing? Tools for exploring behavioural structure in animal movements

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A simple, cost-effective emitter for controlled release of fish pheromones: Development, testing, and application to management of the invasive sea lamprey

<div><p>Semiochemicals that elicit species-specific attraction or repulsion have proven useful in the management of terrestrial pests and hold considerable promise for control of nuisance aquatic species, particularly invasive fishes. Because aquatic ecosystems are typically large and open, use of a semiochemical to control a spatially dispersed invader will require the development of a cost-effective emitter that is easy to produce, environmentally benign, inexpensive, and controls the release of the semiochemical without altering its structure. We examined the release properties of five polymers, and chose polyethylene glycol (PEG) as the best alternative. In a series of laboratory and field experiments, we examined the response of the invasive sea lamprey to PEG, and to a partial sex pheromone emitted from PEG that has proven effective as a trap bait to capture migrating sea lamprey prior to spawning. Our findings confirm that the sea lamprey does not behaviorally respond to PEG, and that the attractant response to the pheromone component was conserved when emitted from PEG. Further, we deployed the pheromone-PEG emitters as trap bait during typical control operations in three Great Lakes tributaries, observing similar improvements in trap performance when compared to a previous study using mechanically pumped liquid pheromone. Finally, the polymer emitters tended to dissolve unevenly in high flow conditions. We demonstrate that housing the emitter stabilizes the dissolution rate at high water velocity. We conclude the performance characteristics of PEG emitters to achieve controlled-release of a semiochemical are sufficient to recommend its use in conservation and management activities related to native and invasive aquatic organisms.</p></div

Housing the PEG6000 emitter better controlled the rate of dissolution at high water velocity.

<p>In a recirculating flume, increasing water velocity accelerated the rate of PEG6000 dissolution. However, housing the emitter (filled circles, r² = 0.69) reduced the effect of velocity on the dissolution rate at velocities >0.25 m s^-1 relative to emitters fully exposed to the flow (white circles, r² = 0.87). Linear regression fits with 95% CI (dashed lines) are included to illustrate the patterns, see text for GLM results.</p

Emitter housing and test tank used during Objective 4.

<p>(a) Design of the emitter housing. The emitter was attached to the dowel with a single rubber band. The housing was mounted in the flow tank as shown, with the bottom open to the water. (b) Schematic of the recirculating flume tank. Flow was maintained with two trolling motors mounted upstream of a PVC collimator. During each trial five emitters were mounted at mid-depth and equidistant across the channel.</p

Performance of the emitter-baited traps (vs. a paired unbaited trap) during sea lamprey control operations.

<p>(a) Box and whisker plots of historical trap efficiency (proportion of the run captured) for each stream as estimated by mark-recapture (data obtained from P. Hrodey, USFWS, outliers omitted). The black triangle indicates the observed trap efficiency during 2012 when 3kPZS-PEG6000 emitters were applied, “n” indicates the number of years historical trap efficiency was estimated. (b) The proportion of the total catch that was captured in the 3kPZS emitter-baited trap with 95% binomial confidence intervals, “n” refers to the total number of sea lamprey captured in baited and unbaited traps during 2012. The dashed line indicates the null expectation of equal catch rate between the paired traps if the 3kPZS-PEG6000 emitter did not influence capture rate (which trap received the bait was alternated on subsequent nights).</p

A schematic of the Ocqueoc River field site.

<p>(a) Lampreys were held in cages at the release point (RP) until the start of the trial. The upstream test area (TA) was equipped with four PIT antennas; two to detect upstream movement into the area (#1 and #2), and one each surrounding the point of emission of 3kPZS, either by polymer emitter or pump tube, to detect attraction (#3 and #4). (b) Detail of the 3kPZS emission apparatus. The PIT antenna surrounded a simulated lamprey nest. At the center of the nest either a PEG6000 emitter was placed (both tests), or the end of a buried tube emerged from the sediment (Test #2 only). When used, the 3kPZS-methanol mixture was pumped from a carboy placed on the platform. In both diagrams the white arrows indicate the direction of water flow.</p

Migratory sea lamprey do not respond to the odor of PEG6000.

<p>Dissolution of PEG6000 (stimulus) into one side of the laboratory raceway did not alter the lateral distribution of sea lamprey vs. the pre-stimulus period (paired t-test, n = 8, P = 0.69).</p