Body Shape of Fishes


Electrofishing students In a new study published in the Journal of Fish Biology, Luke Bower, a graduate of the MS in Biological Sciences (now a doctoral student at Texas A&M), and Kyle Piller, Professor of Biological Sciences, Bower and Piller use "geometric morphometrics", a sophisticated statistical technique designed to analyze body shape, in an entirely new way: analyzing how the shapes of fishes are associated with aspects of the streams in which they live. They were asking the old and still-controversial question "Is there a relationship between the body shape of a fish and the habitat that it occupies?" They collected 580 fishes of 26 species from the nearby Tickfaw River, used gene sequences to determine their relationships, and compared their relationships and shapes with aspects of the stream area that they were collected from, e.g., temperature and flow rate. Using this powerful statistical approach they discovered something new, some that couldn't be discovered in the past: that the place a fish chooses to occupy is very reliably predicted by the fish's shape. This pattern exists even among unrelated species of fish, which is an idea that was formerly disregarded. Their discovery was made possible by the powerful use of gene sequences and the geometric morphometric tools that they used in a new way.