How do the types of fish differ between the MHI and NWHI?
Scientists use the phrase “fish assemblage” to refer to the collection of species and their relative abundance in a given location. It’s a convenient phrase, so we’ll use it here as well. Friedlander and DeMartini used multivariate statistics to place the islands on a statistical “map” based on their fish assemblages rather than on geographic location. Two islands are closer together on this map if they have similar fish assemblages, and further apart if the fish are different. Looking along the horizontal direction of their statistical map, the MHI are clustered together and clearly separated from the NWHI. That is, the fish species found around the NWHI are similar to each other but different from the NWHI. Looking along the vertical dimension of the map, basalt islands such as Gardner, Necker and Nihoa (around which the water drops off quickly into deep reefs exposed to ocean weather) are near each other and separated from the atolls and reefs (which have much more protected shallow
