A gruesome beauty

What lacks a jaw, has horn-like projections for teeth, looks like an eel (but is really a fish) and is found in the Delaware River? The sea lamprey.

Startling in appearance, this anadromous fish spends the majority of its life in its larval, or “ammocoete” stage. When it reaches sexual maturity following a metamorphosis process, the adult sea lamprey travels from the salt water environment of the Atlantic Ocean to spawn in fresh water like that of the Delaware River.

Lampreys excavate nest-like depressions in the riverbed by moving gravel with their mouths. After depositing eggs and sperm, the lamprey lifecycle comes to an end.

The parasitic adult sea lamprey feeds on other fish by attaching its sucker mouth to the prey fish and using its raspy tongue to open a wound and drain the victim of its blood and body fluids.

Although perhaps shocking to observe, particularly in relation to their parasitic practices, sea lampreys display fascinating physical features, including their artfully arranged spiraling teeth and beautiful skin with mottled patterns of silver and gray.