Location
Groningen, The Netherlands
Event Website
http://fishpassage.umass.edu/
Start Date
23-6-2015 11:05 AM
End Date
23-6-2015 11:20 AM
Description
Abstract:
Gregarious behaviour is found throughout the animal kingdom. Although many fish species live in groups during a certain period of their life cycle, rarely has this collective behaviour been incorporated in fish passage studies, which tend to focus on individual behaviour of target species. Near fish passes, local hydrodynamics are highly variable, potentially affecting school cohesion. Since schooling has several drivers, such as antipredatory benefits and energy savings mechanisms, a loss of school integrity might be a reason fish passes act as an ecological trap for fish species that live in schools. An understanding of how hydrodynamics, encountered near fish passes, affect school cohesion and schooling behaviour is needed. A ‘back-to-basics’ study was executed that explored the response of fish schools to hydrodynamics in an experimental setting. The Common Minnow (Phoxinus phoxinus) was chosen, since it is a strong schooling species and abundant in English rivers. Minnows are quite similar in morphology and swimming movements to the important (migratory) salmonids and could therefore serve as a proxy. Movements of schools of two individuals were recorded in flowing and standing water, and their individual trajectories extracted from video data. Results show that minnows switch from a tandem configuration in standing water to a close side-by-side configuration in flowing water. Modelling work revealed that in this side-by-side configuration, energy savings could not be realised. It was concluded that fish aim to maximize information transfer when encountering flow and therefore have to rely on vision more than their lateral line system as the effectiveness of the latter is disturbed by the flow conditions. These findings suggest that passage of schooling fish is highly dependent on flow characteristics as these determine the success of collective movement and navigation through fish passes.
Session B4: New Insights into Schooling Behavior in Response to Flow
Groningen, The Netherlands
Abstract:
Gregarious behaviour is found throughout the animal kingdom. Although many fish species live in groups during a certain period of their life cycle, rarely has this collective behaviour been incorporated in fish passage studies, which tend to focus on individual behaviour of target species. Near fish passes, local hydrodynamics are highly variable, potentially affecting school cohesion. Since schooling has several drivers, such as antipredatory benefits and energy savings mechanisms, a loss of school integrity might be a reason fish passes act as an ecological trap for fish species that live in schools. An understanding of how hydrodynamics, encountered near fish passes, affect school cohesion and schooling behaviour is needed. A ‘back-to-basics’ study was executed that explored the response of fish schools to hydrodynamics in an experimental setting. The Common Minnow (Phoxinus phoxinus) was chosen, since it is a strong schooling species and abundant in English rivers. Minnows are quite similar in morphology and swimming movements to the important (migratory) salmonids and could therefore serve as a proxy. Movements of schools of two individuals were recorded in flowing and standing water, and their individual trajectories extracted from video data. Results show that minnows switch from a tandem configuration in standing water to a close side-by-side configuration in flowing water. Modelling work revealed that in this side-by-side configuration, energy savings could not be realised. It was concluded that fish aim to maximize information transfer when encountering flow and therefore have to rely on vision more than their lateral line system as the effectiveness of the latter is disturbed by the flow conditions. These findings suggest that passage of schooling fish is highly dependent on flow characteristics as these determine the success of collective movement and navigation through fish passes.
https://scholarworks.umass.edu/fishpassage_conference/2015/June23/8
Comments
Presenting Author Bio: After completing an MSc in Marine Biology (2008) and a second MSc in Physical Oceanography (2011), I started my PhD at the University of Southampton in 2012. My research focuses on the behaviour of fish schools in moving fluids, while other work has investigated the downstream passage efficiency of fish schools when encountering fish screens.