Astroscopus guttatus or the northern stargazer is a species of fish belonging to the Uranoscopidae family and was first described by Charles Conrad Abbott in 1860. Members of the Uranoscopidae family are characterized by dorsally or dorsolaterally directed eyes placed on or near the top of a large, flattened cuboid head, an oblique to vertical mouth often lined with cutaneous cirri, and an elongated, sub-compressed body. Typically found on the Atlantic shores between the states of North Carolina and New York in the United States, the northern stargazer can sometimes be confused with its sister species the southern stargazer, Astroscopus y-graecum. Both A. guttatus and A. y-graecum overlap in their distributions in Cape Hatteras One way to distinguish the northern stargazer from the southern stargazer is by the presence of numerous small white spots closely spaced along its head and back, whereas the southern stargazer has fewer, larger spots on its back. The northern stargazer is a moderately sized fish that can reach lengths of 22 inches (56 cm). The northern stargazer can be found buried in sandy substrate at depths up to 120 feet (37 m) where the species remains buried awaiting prey. The strategic placement of the eyes on the top of the head allows for their eyes to remain functional despite being buried. In addition to the location of the eyes, stargazers—as well as other bottom dwelling fish—have the ability to change the height of their eyes by filling tissues at the back of the eye with body fluid. Stargazers also have ventral fins that have been moved forward in such a way that they assist with digging. A. guttatus has pectoral fins that act as shovels allowing the fish to bury itself in seconds. The mouth of the stargazer faces up so that it can ambush prey while hiding in the sandy bottoms of coastal bodies of water. In addition to placement of their mouth, Astroscopus fish can breathe when the water is full of sand or when buried due to a row of fine comb-like structures on the edge of each jaw. These comb-like serrations are positioned in a way that when the jaw is closed, they interlock allowing water to flow through but preventing sand.
Distribution
Astroscopus guttatus is typically found in coastal waters from New York to Virginia. But there have been sightings of the northern stargazer in the waters of South Carolina. Northern stargazers can be found in deep ocean water at depths up to 120 feet or 37 meters. The northern stargazer enjoys rocky reef and soft bottom habitats. In places lacking natural reefs, scientists experimented with placing oyster cages on the bottom of the ocean floor. These scientists observed an increase in fish diversity including an increase in northern stargazer sightings following the addition of the oyster cage as the cage created additional reef like habitat for fish.
Ecology
Northern stargazers live primarily along the eastern seaboard of the United States. They do not swim much except when migrating as they swim clumsily and slowly. Instead, northern stargazers bury themselves in the sand using short side to side motions of their ventral fins and tail to bury themselves until three quarters of their body plane is covered by sandy substrate. If disturbed, stargazers can bury themselves beneath as many as 12 inches of sand to hide from predators. Northern stargazers primarily feed on small fish that swim above them in the sand. The eyes of the northern stargazer are also home to an electrical organ that sits under each eye. The electrical apparatus is composed of 200 thin layers of electric tissue which gives it a jelly or mucus like appearance.
Taxonomy
The northern stargazer was first described by Charles Conrad Abbott in 1860.