Diversity of Fishes
Profile: Dr. Ian Harrison
Dr. Ian Harrison
Dr. Ian Harrison

Dr. Ian Harrison is a content coordinator for the Museum's online courses, Seminars on Science. English by birth and an ichthyologist by training, Ian received his B.S. in Zoology at the University College of North Wales and his Ph.D. from the University of Bristol. He attributes his early interest in marine life to family vacations spent at the coast of Cornwall, in southwest England. "My dad would always make sure that we had a good supply of shrimping nets and a mask and snorkel," recalls Ian, "so as a kid I always had a great time just wandering along the seashore and fishing around in rock pools." At college he became a scuba diver, but admits that despite the hours spent in and under water, "I didn't think about fish too much except for when I was face to face with them underwater." It was a summer internship at the Natural History Museum in London that turned the university student into a serious fish fan.

Ian was assigned to the fish section, and the curators took him around their wonderful historical collections. "I was just fascinated by the amazing diversity," he explains. "Certainly in terms of vertebrates, there's almost nothing that touches them. There's pretty much nothing that fishes don't do. They don't only swim; they walk, and they fly. Fishes span an incredible range of habitats, from the deepest ocean trenches to Tibetan hot springs over five kilometers high. Some can tolerate very high temperatures or salinity four times the strength of sea water-while ice fish can live in temperatures below freezing. African lungfish can pretty much just sit in the mud for a few months or even years, and come back out when the rains return." The London museum gave Ian his first taste of fish diversity, but what really hooked him, as he says, was that, "We know a great deal about them, but there's actually so much more to find out."

Scientists at the museum in London were excited about the application of cladistics as a challenging and promising way to understand relationships between organisms. "I was very much aware that I was watching something very important in terms of the development of scientific theory," Ian recalls. Much of his work focuses on taxonomy and phylogeny: the process of describing species according to their diagnostic characteristics (whether they be morphological, molecular, or behavioral) and explaining the genealogical relationships between the species. "You have to know what the organism is and how you're going to refer to it before you can do much else," he explains. "Because unless everyone's on the same page in terms of how it's described, where it's found, how it's related to other organisms, any other kind of scientific work is on shaky ground."

After completing his Ph.D., Ian studied fish in museums and universities in France, Italy, and Belgium before coming to the American Museum of Natural History (AMNH) in 1994 on a postdoctoral fellowship to work with Dr. Melanie Stiassny, in the Department of Ichthyology. At the AMNH, Ian studied the taxonomy, phylogeny, and biogeography of mullets, an important group of coastal fishes. He loved the challenge and the stimulation of being at the AMNH. "Apart from the fact that the staff here are all particularly brilliant, the museum is very scientifically adventurous. That's part of its character, its reputation. The staff isn't afraid to ask probing questions and challenge scientific theory," he maintains.

Then security beckoned in the form of a permanent job back in England. Ian went to work in a fisheries museum in a town on the coast of the North Sea, called Grimsby; it had been the biggest fishing port in the world in the mid-1900s. "It was a great chance to become involved in some of the applied aspects of fishery science, rather than fish biology per se, and to see firsthand the socio-economic repercussions of the catastrophic decline in 20th-century fisheries. Our goal at the fisheries museum was to work with other museums to figure out how to present an overview of the history of British fisheries," he explains. But Ian missed the AMNH and the unfinished work on mullets that he'd left behind. So in 1996 he returned to New York to restart his postdoc. "My research opened up as many questions as it closed, which is always the way," he says, managing to sound both wistful and content. It turns out that mullets have some interesting muscles of the head that scientists find useful in understanding their evolutionary relationships. Also, the diet of the fish is affected by the development of these muscles, because the muscles control how the fish use their mouth and jaws to feed. Consequently, the study of the development of the muscles can be important in order to recognize how to optimize the feeding conditions for these fish when they are used in commercial aquaculture.