About Raja eglanteria Bosc, 1800
Raja eglanteria, commonly called the clearnose skate (and also the brier skate), gets its common name clearnose skate from the characteristic light-colored to translucent patches along both sides of its rostrum. Its dorsal surface is primarily brown to grey, while its ventral surface is white. The dorsal side of its pectoral fins also has dark brown to black bars and spots. This species has a roughly rhombic disc shape, where the snout and pectoral fins form an approximate right angle. Mature clearnose skates can reach up to 79 cm (31 in) in total length and 52 cm (20 in) in width. The tail makes up approximately half of the skate’s total length. Another key characteristic is a line of thorns running along the middle of the back and tail. The rest of the dorsal surface is covered in small prickles, which is how the species got the alternate common name brier skate. These prickles are concentrated on the anterior portion of the disc, as well as along the spine, the same as the thorns.
The geographic range of Raja eglanteria extends along the eastern coast of the United States, from Massachusetts in the north to Florida in the south. Its range continues around the Florida peninsula into the eastern and northern parts of the Gulf of Mexico. Like other skate species, clearnose skates are demersal. They can be found on soft substrates such as mud and sand, or on harder surfaces such as rock and gravel. Clearnose skates prefer shallow water that is at least partially saline, with a salinity of 22 ppt or higher. These skates are most commonly found at depths less than 111 m, but can occur in waters as deep as 330 m. Their depth distribution changes with the seasons: Raja eglanteria is found mostly further inland during winter and spring, and offshore during summer and fall. Clearnose skates can live in water temperatures ranging from 41 to 86 °F (5 to 30 °C). Their preferred temperature ranges vary by latitude, with skates in the northern parts of their range tolerating a wider temperature range than those in southern areas.
The life cycle of the clearnose skate begins when a female deposits an egg. The embryo grows as its cells divide. During cell division, regionalization of the developing skate becomes visible, with distinct head and tail regions. Development continues with the formation of neural components, as well as spiracles and gill filaments. Other structures and organs continue to differentiate and grow, and finally the mottled pattern of the dorsal surface develops. Embryos incubate inside the egg case for approximately 12 weeks. Eventually, the embryo outgrows the egg case, and breaks free by extending its pectoral fins and tail. Newly hatched clearnose skates measure approximately 13 to 15 cm (5.1 to 5.9 in) in total length, and 8.4 to 10.5 cm (3.3 to 4.1 in) in disc width. Age at maturity ranges between two and six years, depending on sex: females take longer to reach maturity than males. The minimum size of a mature male is 56 cm (22 in) in total length, while for mature females it is 59 cm (23 in).
