REANALYSIS 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 t he data in the best ways possible with contemporary techniques, and de veloped the idea that benthic communities were continuously inter-grad ed and strongly dependent on substrate type. Dr Jones proposed four di stinct community types based on a combination of sediment, characteriz ing species and numbers and size of dominants. Fifty years on, this da ta set can now be re-analysed using multivariate statistical methods a nd the huge processing power of modern computers. Here, a re-analysis is presented using hierarchical agglomerative clustering of Bray-Curti s similarity indices, represented by dendrograms and non-metric multid imensional scaling plots, in an attempt to compare Jones' subjective c ommunity groupings with those obtained objectively. Despite problems e ncountered with the assortment of different gears used, some confirmat ion of Jones' divisions was found. (C) 1998 Academic Press Limited.