Re-analysis of an Historical Benthic Data Set from the Irish Sea

In the period 1946–1953 Dr N. S. Jones sampled the benthos around the south of the Isle of Man at over 200 sites. At the time, he analysed the data in the best ways possible with contemporary techniques, and developed the idea that benthic communities were continuously inter-graded and strongly dependent on substrate type. Dr Jones proposed four distinct community types based on a combination of sediment, characterizing species and numbers and size of dominants. Fifty years on, this data set can now be re-analysed using multivariate statistical methods and the huge processing power of modern computers. Here, a re-analysis is presented using hierarchical agglomerative clustering of Bray–Curtis similarity indices, represented by dendrograms and non-metric multidimensional scaling plots, in an attempt to compare Jones’ subjective community groupings with those obtained objectively. Despite problems encountered with the assortment of different gears used, some confirmation of Jones’ divisions was found.