You can find hundreds of different types of shells on North Sea beaches. We distinguish between 2 types: sea snails, which consist of one piece, and bivalves, which consist of two parts. (you usually only find one part of the bivalvia on the beach)
The animals make their shell from calcium that they extract from the water. Their growth rhythm is determined by the quantity of food on hand. That's why shells grow faster in the summer than in the winter - there is more plankton in the water. Their growth process is gradual; every time they grow they make their shells a bit bigger. You can see that gradual growth process on the shell's ridges. That's why those ridges are called growth lines. On a bivalvia shell they are horizontal from top to bottom, on a sea slug they are vertical from top to bottom.
Below you can see the 10 most widespread shells on North Sea beaches. Place them next to their correct name and discover what kind of animals they are!
There are more than 220 different kinds of fish in the North Sea. Fishing is concentrated on about 25 species. Most of the fished species are Gadiformes (cod, pollack, haddock, whiting), Flatfish (plaice, sole, dab, turbot, brill) and others (herring, sprat, pout, sand eel and mackerel).
Compared to other seas, the North Sea is very productive and is heavily fished. Every year 3 to 3.5 million tons of fish are pulled out of the water.
Below you can see 10 fish that appear frequently in the North Sea. Place them next to their correct name and discover what kind of animals they are!