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Saturday September 17 2011 BIBI Monitoring Report

posted Nov 18, 2012, 10:40 PM by Derek Brown   [ updated Jan 9, 2013, 7:49 PM ]

Eleven LFP StreamKeepers turned out Saturday morning, Sept. 17, to collect aquatic insects and other macroinvertebrates on McAleer Creek about 100 yards upstream from Perkins Way. The skies were threatening, but the temperature was balmy, and it turned out to be an excellent morning on the stream. The group included three Shorecrest students, and was joined by Jo Wilhelm of the King County Department of Natural Resources and Parks.

Aquatic macroinvertebrates include several types of flies, beetles, worms and crustaceans that live all or part of their lifecycles in streambeds. Since some of these organisms are tolerant of polluted conditions, and others are very intolerant, understanding the types of macroinvertebrates that live in a stream is an important indicator of the overall health of the stream. This method of analysis is called the benthic index of biologic integrity, or BIBI for short.

The purpose of the collection was to help evaluate two different sample collection protocols. Most groups doing BIBI base their analyses on the average of three samples per site. Others feel that eight samples collected over a larger section of streambed gives a more accurate analysis. King County is leading a study, with partners Pierce and Snohomish Counties, to see if the results from the two methods are significantly different. So in our work on Saturday we collected a total of eight samples. Three will be analyzed separately, and then all eight will be analyzed together to see how the two methods compare. Similar side-by-side sampling is being conducted at many locations throughout Western Washington to get a large enough database to draw meaningful conclusions.

Thanks to the residents who allowed us to work on their properties, and thanks to all who gave up their Saturday morning to help improve this important stream monitoring tool.