Twait shad destruction. Conservation of this species is covered by Appendix III of the Bern Convention and Appendix II and V of the European Community Habitats Directive. The twait shad is a typical herring-type fish and much resembles the allis shad. It has no lateral line and the belly is more rounded than that of the sprat and Baltic herring. The gill cover is ridged and the caudal peduncle has large, plate-like scales. This fish is more colourful than the Baltic herring. The back is a bluish green colour and the head brownish with a golden tinge on the operculum. The flanks
Whitefin dogfish is distinctive in being the only "Centroscyllium" species with abrupt black markings beneath its head, trunk, and pectoral fins, with a black stripe running from under the caudal peduncle to over the pelvic fins. These markings are in fact concentrations of tiny light-emitting photophores. Unusually, this shark also has photophores along the undersides of its upper eyelids. What function these structures could serve is unclear; Tchernavin speculated that they could be used to illuminate prey or stimulate the eye. The rest of the body is gray-brown, with white fin margins. There are numerous small cone-shaped, hooked prickles over the body,