What Could Chemistry Tell Us About the Ecology of Sharks and Rays?
Sharks and rays are a group of fishes that are referred to as elasmobranchs. This designation refers to the multiple gill slits (5-7) they have, an arrangement which is different from the gill openings of other fishes. Another major difference between sharks and rays and other fishes is that the skeleton of elasmobranchs is made up of cartilage rather than bone. Sharks and bony fishes alike are exposed to wide range of naturally occurring elements that are dissolved in the water that surrounds them. These elements may enter a fish and become incorporated into their bodies’ as a byproduct of respiration and feeding. Some elements will be excluded from the body and the concentration of others will be carefully regulated. However, the concentration of some elements that are taken up by fishes can reflect the concentrations that they were exposed to in seawater. As a fish grows and time passes, distinctive concentrations of elements that are incorporated into the hard body parts of fishes
