Key to the Identification of Skates and Rays (Raja) Found in British Waters

Note on how to use the key:

Starting at section 1 compare each of the two descriptions (a) and (b).
Having decided which of these best fits the specimen follow the arrows » to the section number indicated.
Continue until the specimen is identified

1 (a) under-surface black, blueish-black or white heavily coloured with bluish black markings » 2

(b) under-surface pure white, or white with a few small dark areas only » 4

2 (a) black or grey markings confined only to a band along the posterior edge (that nearest the tail) of the wings = R.alba white bellied skate, owl or bottle nosed ray (see also section 17b)

(b) black or grey markings not confined only to a band along the posterior edge of the wings » 3

3 (a) snout very much elongated; distance from the mouth to tip of snout = 1/3rd wing span = R. oxyrhynchus long nosed skate

(b) snout elongated but not extremely so; distance from the mouth to tip of snout = ¼ wing span = R. batis common skate

4 a) ocellus present (an ocellus is a very distinct mark or group of spots found approximately in the centre of each wing on its upper surface. They occur one on each wing) » 5

(b) ocellus absent » 9

5 (a) ocellus entirely black = R. clavata thornback ray (see also section 14a)

(b) ocellus not entirely black » 6

6 (a) ocellus entirely white » 7

(b) ocellus not entirely white » 8

7 (a) upper surface light brown marked with darker brown stripes and many white spots = R. undulata undulate ray

(b) upper surface mottled black and grey = R. clavata thornback ray (see also section 14a)

8 (a) ocellus made up of individual spots = R. monttagui spotted or homelyn ray note 1

(b) ocellus black and yellow marbled, very prominent = R. naevus cuckoo ray

9 (a) upper surface spotted » 10

(b) upper surface not spotted » 13


10 (a) spots lighter than background » 11

(b) spots darker than background » 12

11 (a) upper surface plain except for about six small white spots = R. circularis sandy ray (see also section 16b)

(b) upper surface light brown marked with darker brown stripes and many white spots = R. undulata undulate ray

12 (a) spots reach edge of disc = R. brachyura blonde ray note 2

(b) spots do not reach edge of disc = R. monttagui spotted or homelyn ray note 1

13 (a) large spines on upper surface of disc » 14

(b) no large spines on upper surface of disc » 15

14 (a) spines not striated; some with swollen bases embedded in skin; occur on upper and lower surfaces of the disc which is rough like course sandpaper; colouration of upper surface very variable but usually mottled black and grey = R. clavata thornback ray

(b) spines striated; bases broad and flat but not spherical; never occur on lower surface; a row of 12-19 prominent spines down mid line of disc and tail; disc smooth between spines, brownish colour = R. radiata starry ray

15 (a) snout not elongated or only slightly so » 16

(b) snout elongated » 17

16 (a) upper surface with whitish stripes = R. microcellata painted or small-eyed ray

(b) upper surface plain or with six white spots; two rows of heavily curved, closely packed spines along each side of the tail = R. circularis sandy ray

17 (a) leading edges of the wings, excluding the snout, form an acute (sharp) angle; two rows of spines along the tail = R. fullonica shagreen ray

(b) leading edges of the wings, excluding the snout, form an obtuse (blunt) angle; one row of spines along the midline of the tail = R. alba white bellied skate, owl or bottle nosed ray

Notes:

Note 1 R. monttagui spotted or homelyn ray. Spotting is variable. In juveniles only the ocellus may be present and the other spotting little or absent. A slimy fish

Note 2 R. brachyura blonde ray. Spotting always present even in juveniles. There are aften lightish patches in background colour but these may occur anywhere and should not be confused with ocelli. A firm fish; the skin having a very fine sandpaper texture.


The above key is produced by courtesy of The Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Lowestoft, Suffolk.