My main research focus is the systematics and biology of copepods, with special emphasis on parasitic and planktonic forms. I am interested in the adoption of parasitism which has happened in at least 10 separate lineages in copepods and they exploit almost every other phylum as hosts from Porifera to chordates. I find that WoRMS is enormously useful when I need to get up-to-date host nomenclature. I believe that there is robust evidence from host-specificity and from biogeography that allows us to look at the relative importance of co-evolutionary versus colonization events in determining host-parasite relationships. I am involved in the preparation of an interactive web-based key for the identification of sea lice (family Caligidae). These copepods are one of the major health problems for farmed fish worldwide. I am also interested in the colonization of marine and anchialine caves by crustaceans. These habitats seem to serve as refuges for basal representatives of numerous lineages and I have been studying the basal radiation of the Calanoida prior to their conquest of the open ocean pelagic zone.

I have been employed as a researcher at the Natural History Museum, London since 1974. I am also the Secretary of the Zoological Society of London, and I currently serve as a Trustee on the Board of SAHFOS, the Sir Alister Hardy Foundation for Ocean Science.

Taxonomic terms: Branchiura [WoRMS]; Copepoda [WoRMS]; Mystacocarida [WoRMS]; Tantulocarida [WoRMS]