Serpent's Table Brittlestar

O. albida has separate sexes, external fertilization and pelagic larvae. The maximum age is estimated at 3 years. This shortlived species shows a relatively fast-growing strategy. O. albida may be particularly vulnerable to predation. It shows a high reproductive effort, thus maintaining the populations (Wolff, 1973; Fish & Fish, 1989; Gage, 1990). The species moves freely on the sediment (Mortensen, 1927). Small invertebrates, particularly polychaetes, bivalve mollucs and crustaceans, comprise the main food of Ophiura spp. There is evidence that scavenging and surface deposit feeding are also fairly frequent (Wolff, 1973; Warner, 1982; Fish & Fish, 1989). Young stages of trematodes and nematodes can be found in the body cavity of this brittle star (Mortensen, 1927).

Ophiopluteus larva. Summer

Brittle stars consist of a central disc clearly separated from the slender, very agile and very strong arms. Ophiura albida is very similar to Ophiura ophiura and can be distinguished from this species by the absence of pores between the arm plates and by its fewer arm comb papillae. The top is reddish to orange-brown; the bottom side is dirty white.

In both periods Ophiura albida was widely spread across the Belgian part of the North Sea and was only absent in the eastern coastal zone. The species was found in relatively high densities (1976-1986 period: maximum 100 ind./m2; 1994-2001 period: maximum 900 ind./m2).

From about 10 to more than 200 m depth, common on sand, muddy sand and fine gravel, all round the British Isles

O. albida lives in areas with a variety of sand and muddy sand deposits.

Ophiura albida prefers fine to coarse-grained sediments (median grain size 150-650 µm) without any preference for a particular median grain size. The species furthermore prefers sediments with a low to medium mud content (maximum 40%).

O. albida has a disk with rather coarse scales. The diameter of the disk can be up to 15 mm. The arms are about four times the diameter of the disk. The dorsal and ventral arm plates have a convex outer edge. The mouth shield is small, approximately one-third of the disk radius. In contrast to O. texturata (q.v.) there are no pores present between the lower arm plates. The colour of the dorsal surface usually is reddish-brown, that of the radial shields whitish (Mortensen, 1927; Southward, 1972; Gage, 1990; Hayward & Ryland, 1990).