Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

24-6-2015 3:15 PM

End Date

24-6-2015 3:40 PM

Description

Abstract:

The awareness of the importance of free fish migration in the Netherlands is reflected in the increasing number of fishways that has been built in the past decade. The intention is that all the bottlenecks will be solved before 2027.

Equally important as the realization of fishways, is the evaluation of the design. In other words, are all species and size classes that want to pass, truly able to pass the structure. The challenge in this type of research is to avoid interference of the measuring tools with the fish migrants. The conventional monitoring fyke, does not meet this requirement. Migration is obstructed and the gear is highly selective for small fish. Emerging electronic techniques offer this opportunity and makes it possible to watch fish migration behaviour on the road through the fishway. The use of a resistivity Fish Counter will be illustrated by means of a case study.

The counter detects the swimming direction and size of the passing fish. Species identification is achieved by the application of a camera, triggered by the passing fish. The placement of a counter station at both sides of the fishway, gives the unique opportunity to determine the efficiency in terms of the ratio between the number of fish entering the downstream side and the number of fish exiting at the upstream side. An example will be given of a fishway that originally was reviewed as a good functioning construction.

However, measurements of the efficiency showed that only a small part of the fish community was able to pass. The results also uncovered the weak spot in the design. This was not regarded as a failure, but as an opportunity to make use of the hidden potential of this fishway. It also contributed to the improvement of this type of design in general.

Comments

Presenting Author Bio:

Jan is a fisheries biologist for more than 25 year. The focus is on fish migration, fishway design and fish stock assessments with special interest in modern techniques. He started in 2005 with a private company, VisAdvies BV. This company concentrated further on applications like Acoustic telemetrie PIT telemetrie, sonar (fish stock assessment), fish counters etc..

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Jun 24th, 3:15 PM Jun 24th, 3:40 PM

Session E8: Efficiency Measurements as Tool in Evaluating Fishways

Groningen, The Netherlands

Abstract:

The awareness of the importance of free fish migration in the Netherlands is reflected in the increasing number of fishways that has been built in the past decade. The intention is that all the bottlenecks will be solved before 2027.

Equally important as the realization of fishways, is the evaluation of the design. In other words, are all species and size classes that want to pass, truly able to pass the structure. The challenge in this type of research is to avoid interference of the measuring tools with the fish migrants. The conventional monitoring fyke, does not meet this requirement. Migration is obstructed and the gear is highly selective for small fish. Emerging electronic techniques offer this opportunity and makes it possible to watch fish migration behaviour on the road through the fishway. The use of a resistivity Fish Counter will be illustrated by means of a case study.

The counter detects the swimming direction and size of the passing fish. Species identification is achieved by the application of a camera, triggered by the passing fish. The placement of a counter station at both sides of the fishway, gives the unique opportunity to determine the efficiency in terms of the ratio between the number of fish entering the downstream side and the number of fish exiting at the upstream side. An example will be given of a fishway that originally was reviewed as a good functioning construction.

However, measurements of the efficiency showed that only a small part of the fish community was able to pass. The results also uncovered the weak spot in the design. This was not regarded as a failure, but as an opportunity to make use of the hidden potential of this fishway. It also contributed to the improvement of this type of design in general.

https://scholarworks.umass.edu/fishpassage_conference/2015/June24/45