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
Operculum (gastropod) sea shell fragrance) or ""kai kou"" (Japanese: 甲香, "lit." shell/armour fragrance) respectively. Incense producers in these countries use the operculum of many conches and other marine snails, including those found in Southeast Asia, South America, and East Africa. The opercula are traditionally treated with vinegar, alcohol and water in order to remove any fishy smell. The clean opercula are then ground to a powder and used as a scent fixative, in a technique similar to that used in perfumes with certain plant resins. When burnt on its own, high quality operculum reportedly smells of castoreum or other animal musks, while