Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

24-6-2015 4:00 PM

End Date

24-6-2015 4:15 PM

Description

Abstract:

The use of BL/s, i.e. body lengths per second (dimensions of s-1), to express relative swim speeds for fish is very common. The physiological literature demonstrates the following: a) fish length is a strong predictor of swimming performance; b) longer fish achieve higher absolute swim speeds (dimensions of m/s) than shorter ones, at least for the same species; c) when swim speeds are expressed in BL/s, shorter fish have higher relative speeds than longer ones. Therefore, it is difficult to estimate swim speeds of large fish from small fish and vice versa, when using these absolute or relative swim speed metrics. It is important to recognize that regressions with data from small fish (e.g. juveniles) expressed in BL/s, would lead to overestimates of absolute swim speeds for large fish. It also follows that BL/s regressions with data from large fish, would lead to underestimates of absolute swim speeds for small fish. Yet, costs and complexity often lead to considerable data sets for small fish and limited tests with large fish, even though swim speed estimates are frequently needed for large fish. Regression strength for the same data sets, is higher when using dimensionless swim speed expressions, rather than BL/s. Such ecohydraulic analyses, demonstrate swimming performance similarity between small and large fish and provide better absolute swim speed estimates. Furthermore, ecohydraulic analyses point to efficient strategies for testing length classes, particularly when swim speeds for considerable numbers of sizes and species are needed.

Comments

Presenting Author Bio: Christos (Chris) Katopodis is a Professional Civil Engineer, International Consultant, Adjunct Professor (1995-2014) and President of Katopodis Ecohydraulics Ltd. The company develops integrated and innovative solutions which transcend relevant disciplines by bridging water related engineering and ecology, or ecohydraulics. Katopodis Ecohydraulics Ltd. brings worldwide experience and provides consulting services, including: a) expert advice on planning and design to address and mitigate environmental concerns, protect, pass or exclude fish, provide E-flow regimes (i.e. ecological, in-stream or environmental flows), assess or advance new technologies, develop guidelines, and enhance or restore habitat and river health; b) advice on regulatory issues, environmental assessments and mitigation options, particularly for fish and fish habitat; c) workshops and short training courses.

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Jun 24th, 4:00 PM Jun 24th, 4:15 PM

Session B9: Size Matters Even for the Ubiquitous Fish Speed Metric of BL/S

Groningen, The Netherlands

Abstract:

The use of BL/s, i.e. body lengths per second (dimensions of s-1), to express relative swim speeds for fish is very common. The physiological literature demonstrates the following: a) fish length is a strong predictor of swimming performance; b) longer fish achieve higher absolute swim speeds (dimensions of m/s) than shorter ones, at least for the same species; c) when swim speeds are expressed in BL/s, shorter fish have higher relative speeds than longer ones. Therefore, it is difficult to estimate swim speeds of large fish from small fish and vice versa, when using these absolute or relative swim speed metrics. It is important to recognize that regressions with data from small fish (e.g. juveniles) expressed in BL/s, would lead to overestimates of absolute swim speeds for large fish. It also follows that BL/s regressions with data from large fish, would lead to underestimates of absolute swim speeds for small fish. Yet, costs and complexity often lead to considerable data sets for small fish and limited tests with large fish, even though swim speed estimates are frequently needed for large fish. Regression strength for the same data sets, is higher when using dimensionless swim speed expressions, rather than BL/s. Such ecohydraulic analyses, demonstrate swimming performance similarity between small and large fish and provide better absolute swim speed estimates. Furthermore, ecohydraulic analyses point to efficient strategies for testing length classes, particularly when swim speeds for considerable numbers of sizes and species are needed.

https://scholarworks.umass.edu/fishpassage_conference/2015/June24/11