Raja
Raja is a genus of skates, a type of cartilaginous fish closely related to sharks and rays. Skates are characterized by their flattened bodies, pectoral fins that extend forward to form wing-like structures, and a pair of small dorsal fins on their tails. They are found in marine environments worldwide, typically inhabiting the bottom of the ocean floor.
Common Names
Species within the Raja genus are commonly referred to as skates, with individual species having specific names. For example, Raja clavata is known as the Thornback skate, while Raja batis is called the Common skate.
Characteristics
Skates possess a number of distinct characteristics that set them apart from other fish. These include:
- A flattened body shape
- Enlarged pectoral fins that fuse to the head, forming wing-like structures
- A pair of small dorsal fins on the tail
- Ventral mouth located on the underside of the body
- Five gill slits located on the underside of the head
- A pair of claspers on the ventral surface of males, used for mating
Skates also have a number of adaptations that enable them to live on the seafloor, including:
- Specialized sensory organs (ampullae of Lorenzini) that detect electrical fields, allowing them to locate prey buried in the sand
- Spiracles, openings on the dorsal surface of the head, that allow them to breathe while resting on the seabed
- Pelvic fins that act as stabilizers and help with maneuvering
Environments
Raja species are found in a variety of marine environments worldwide, including:
- Coastal waters
- Continental shelves
- Deep-sea environments
They prefer sandy or muddy bottoms and can be found at depths ranging from shallow waters to over 2000 meters. Skates are generally benthic animals, meaning they spend most of their time on the seabed. They feed on a variety of prey, including crustaceans, mollusks, and smaller fish.