A Sampling Technique for Littoral Stone Dwelling Organisms
- 1 January 1979
- Vol. 33 (1) , 106-112
- https://doi.org/10.2307/3544518
Abstract
A reliable method of quantitative sampling on stony substrata was elaborated during an investigation of the littoral leech fauna in Lake Esrom, Denmark. The method requires a rather homogeneous substratum and can be used only for strictly stone living organisms. Sample units consisted of randomly selected clusters of stones from an area of about 185 cm2, each including a sample of gravel from underneath the stones. One fortnightly sample (primary sample, 100 stones) required on average 13.8 sample units. The total surface area of stones (i.e., larger than 2.5 .times. 2.5 .times. 1.0 cm) was calculated for entire samples after measuring length (L), width (W) and height (H) of each stone. The term .pi./LW + LH + WH) was used as an estimate of surface area. The ratio between surface area of stones and bottom area was deduced from 5 samples each of 1 m2 of bottom, to have a mean of 2.77 m2 stone surface area per m2 of bottom. Additional samples of leeches from stones of fist size showed no difference in mean individual dry weight but improved estimates of growth and production. Sampling interval was 2 wk for both the primary and the additional sampling.This publication has 0 references indexed in Scilit: