Ecological Evaluation Technical Guidance - State of New Jersey

Surber or Square-foot BottomThis sampler consists of a strong close-woven fabric (0.595-mm opening) approximately69-cm (27 in.) long held open by a one-square-foot metal frame hinged at one side toanother frame of equal size. The sampler is generally used in procuring samples in fastflowingstreams less than 1m deep. It can also be used in pools where the water depth iswadeable. Three replicate samples are usually obtained at each sampling station.Carefully place the sampler in position with the net opening facing upstream, using thecurrent to hold the net open while standing downstream and to the side of the samplingarea. By imbedding the separate two- or four-inch extensions of the horizontal frame, thesampled area will be more effectively isolated. When taking replicate samples, alwayswork across or in an upstream direction. Dislodge the rocks, stones, and other bottommaterial within the frame to a depth of at least 2 inches and collect them in the net.Remove the sampler and empty the contents into a plastic tub. Carefully inspect thelarger rocks and stones removing any organisms clinging to them, and discard the stoneswhen cleaned. Also carefully inspect the net and remove any organisms remaining. Afterthe larger materials have been inspected and removed, add a small amount of water to thetub and pour the slurry through an US Standard No. 30 sieve. This may have to berepeated several times to completely empty the tub.Grab SamplersThe Ponar, Peterson, and Ekman grab are the most commonly used grab samplers. ThePonar is similar to the Peterson except that it has side plates and a screened top to preventsampling loss. The Ekman grab is useful in sampling silt and muck in water with littlecurrent. Extreme care should be employed when locking open the jaws of the samplersbecause premature tripping will squash or sever fingers or hands. Handling by theattached line is recommended with an open sampler. Carefully lower the grab to thebottom so as not to agitate the substrate prior to sampling. Slacken the rope to trip jaws(the Ekman grab employs a messenger, which is released by the operator) and retrieve thesampler. Place it in a plastic tub or large screened bin and carefully open the samplerjaws to release the sample. The sample should be discarded if sticks or stones haveobstructed the jaws or if there is incomplete closure for any other reason. Inspect thelarger debris for organisms and discard the debris when cleaned. Filter the samplethrough a #30 sieve to remove small particles.Rapid BioassessmentBenthic rapid bioassessment procedures (RBPs) usually employ direct sampling ofnatural substrates, as do Surbers and grab samplers. Under certain conditions, however,such as in large rivers, the use of artificial substrates may be more appropriate for RBPanalysis. The collection procedure should provide representative samples of the benthicmacroinvertebrate fauna from comparable habitat (substrate) types at all stations in aparticular survey. Either single or multiple habitat samples can be employed dependingon which is more suitable for a particular survey. A riffle and run habitat with rocksubstrate will generally provide the most diverse community of major benthicmacroinvertebrate groups. If the stream or river is not wadeable or has an unstablesubstrate, fixed structures (e.g., submerged boulders, logs, bridges, and pilings) canEcological Evaluation Technical Guidance Document 120Version 1.2 8/29/12