Spotted rat fish

Introduction:

The spotted ratfish, Hydrolagus colliei, is a chimaera found in the north-eastern Pacific Ocean. Often seen by divers at night in the Pacific Northwest, this harmless shark relative gets its characteristic name from a pointed rat-like tail. The ratfish lays leathery egg cases on the bottom of muddy or sandy areas which are often mistaken by divers as something inanimate. While mainly a deep-water species, it occurs at shallower depths in the northern part of its range. The generic name, Hydrolagus, comes from the Greek words "hydro", meaning water, and "lagus", meaning hare, and the specific name honors Alexander Collie, who was a ship surgeon and early naturalist. The ratfish is not typically eaten by humans and is not commercially caught.


Diet:
The spotted ratfish swims slowly above the seafloor in search of food. Location of food is done by smell. Their usual hunting period is at nighttime, when they move to shallow water to feed. Spotted ratfish are particularly drawn to crunchy foods like crabs and clams. Besides crabs and clams, the spotted ratfish also feeds on shrimp, worms, small fish, small crustaceans, and sea stars. Species known to predate on the spotted ratfish include soupfin sharks, dogfish sharks, Pacific halibut, and Pigeon guillemots.

Reproduction:

Like some sharks, spotted ratfish are oviparous. Their spawning season peaks during the spring to autumn months. During this time, the female releases up to two fertilized eggs into sand or mud areas of the seabed every 10 to 14 days. The extrusion process can last anywhere from 18 to 30 hours and the actual laying can last another four to six days. The egg sack is leather-like, five inches long, and has a filament connected to it which is used to attach it to the ocean floor when it is let go by the mother. It is not unheard of to see a female ratfish swimming around her newly laid eggs, in hopes of preventing predators from finding them. Development of the egg can take up to a year, which can be dangerous because the eggs are sometimes mistaken for inanimate objects by divers. When the young finally hatch, they are about 5.5 inches (14 cm) in length and grow, reaching 11.8 inches (30 cm) in length their first year.