Preliminary Examination of Gill Vasculature in the Grey Snapper (Lutjanus griseus) using Vascular Corrosion Casting

Preliminary Examination of Gill Vasculature in the Grey Snapper (Lutjanus griseus) using Vascular Corrosion Casting

While much research has been done on the gross structure and function of gills in bony fish, little work has been done to examine the blood spaces enclosed by the gill structure. The objective of this research project is to compare and contrast the blood spaces in the Grey Snapper (Lutjanus griseus) in relation to overall gill structure and the respiratory vasculature in particular. A single fish was caught using hook and line. The specimen was humanely euthanized using an excess of anesthesia (MS-222, tricane methansulphonate) in seawater. The gills were cleared of blood by perfusion with saline solution followed by perfusion with a liquid polymer (Mercox , methylmethacrylate). To remove the soft tissue around the cast, a 3 molar solution of sodium hydroxide was used. The resulting cast was examined using light microscopy and photographed to characterize the blood spaces in comparison with published diagrams and descriptions of gill structures of bony fishes. The structures observed include the afferent branchial arteries, afferent filament arteries, filament central sinus, and lamellae. The afferent branchial arteries and filament arteries transport deoxygenated blood to the lamellae which are the specific places where gas exchange takes place. In addition to gas exchange, the lamellae are also the site of ion transfer and pH stabilization. Although it is believed that most bony fish share this overall structure, few fishes have been examined at this level. This is, therefore, an area of research that offers many new opportunities for study.