Browsing by Author "Zielinski, Daniel Patrick"

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    Bubble barrier technologies for common carp.
    (2011-03) Zielinski, Daniel Patrick
    Great ecological benefit will be gained if effective barriers can be constructed to control the movement of invasive common carp. Carp feeding habits lead to an over-enrichment of nutrients in lakes that dramatically reduces water quality and ecosystem health. Bajer et al. [2010] demonstrated that in Minnesota lakes, juvenile carp are recruited from nursery lakes to larger water bodies through small connecting channels. Reducing juvenile carp recruitment through the use of a barrier at the entrances to the interconnecting channels could prove useful in an integrated carp management plan for the entire watershed. Current barrier technologies are not well suited for these sites due to the shallow water and rapidly changing water level. This research focuses on the use of bubble curtain barriers, which has been relatively ignored in previous barrier studies, as a barrier technology that shows promise for this application. Bubble curtains generate distinct acoustic and hydrodynamic fields, and through proper manipulation could be used to deter juvenile carp migration. The initial stage of the barrier design was to quantify and measure the physical fields generated by a bubble curtain. An understanding of the physical fields helps to design full barrier systems by exploiting certain features of the bubble curtains. Experimental data revealed that a coarse-bubble curtain created a weaker flow field, but a stronger acoustic field than a fine-bubble diffuser. The subsequent stage of research included barrier tests with live carp using a PIT tag tracking system, which allowed quantification of carp passage over a barrier sans video recording. Three incrementally stronger bubble barriers were designed. A single diffuser design exhibited a mildly retarding effect of carp passage time (passages were delayed 10-15 sec) but not on the actual number passage attempts. Two separate multi-diffuser barriers (varying in configuration and air-supply) exhibited approximately a 75% decrease in carp passages, in upstream and downstream directions. The reduction of passes for each barrier was calculated by taking the ratio of the number of passages during a barrier-on trial to the number of passages during a control (barrier-off) trial. Carp mobility remained constant between tests, indicating that the two larger barriers did not limit total carp activity, but limited carp passage over the barrier. This research represents the first stage of characterization of bubble curtain features with respect to carp sensory systems and rigorous testing of bubble barriers under controlled laboratory settings. The experimental results suggest that bubble barriers create a flexible barrier that appears to deter juvenile carp movement in shallow channels, and may prove to be an effective tool in an integrated carp management plan.
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    An Engineering Perspective on Invasive Fish Control: A Study of Bubble Curtain Deterrent Systems to Control Carp Movement
    (2013-07) Zielinski, Daniel Patrick
    The objective of this research was to investigate the ability of bubble curtain deterrent systems to inhibit the movement of invasive fish. Bubble curtains, which consist of a wall of bubbles (e.g. produced by forcing air through perforated pipes), fall into the category of behavioral deterrent systems that rely on aversive stimuli (e.g. sound and light) to guide fish in taxon specific manners. These systems provide advantages over physical/mechanical screens because they do not restrict fluid flow or negatively impact navigation. Bubble curtains are particularly appealing, because they are less expensive than other electrical or sonic barriers, are easily maintained, safe, and produce complex acoustic and hydrodynamic stimuli which may be optimized to deter fish movement. However, few studies have examined whether or how bubble curtains might work. In three studies, the common carp (Cyprinus carpio), a cyprinid responsible for water quality degradation in shallow water ecosystems, was used to investigate how bubble curtains influence fish behavior and might be optimized. First, through a laboratory experiment, two different bubble curtains were shown to reduce passage of common carp by 75-80% in both up- and down-stream directions. These findings also suggested that avoidance behaviors were attributed to fluid motion and sound stimuli. Second, a field test demonstrated that the performance of a bubble curtain under natural conditions was consistent with laboratory results, blocking 57±12% of downstream swimming carp, versus 75-80% in the laboratory. Third, a fish movement model based on diffusion theory and phonotaxic response was derived. In a novel application, a stability analysis of the fish movement model demonstrated that acoustic stimuli produced by the bubble curtains can be sufficient to disrupt movement (i.e. deter passage) of common carp. Overall, I have shown through rigorous experimental and holistic quantitative analysis that bubble curtains can indeed deter common carp movement, but improvements must be identified in order for bubble curtains to remain a viable management tool in the future.