common or edible sea urchin
The edible sea urchin is a large urchin with short but strong spines: mostly they are pink in color, but sometimes white. The common or edible sea urchin is the largest echinoid in the northsea. It can be found in the littoral zone of the sea up to 40 meters depth.
The common sea urchin behaves like a grazer on the bottom of the northsea: It feeds on the blades of seaeweeds and kelps and all those algae that grow on rocks: only the encrusted algae are save for its grazing.
But the common sea urchin is an omnivore: It also feeds on worms, barnacles, hydroids and tunicates.
A large (male) Ballan wrasse, Labrus bergylta, under a canopy of dabberlocks in the North sea. To right down two edible sea urchins can be seen, clibbing up and down the stalk. They feed on the leaves and on the "Aufwuchs", algae that are attached to blades of the dabberlocks. The sea urchin uses its tube feet to suck itself against the stalk.
the edible sea urchin, uni
The edible sea urchin is sought for its roe. Roe is the name for the male and female gonads, both are edible. The roe is a valuable product, the price is determined most importantly by the color (orange is the best) and the roe must be formed and firm. There is much demand for roe from Japan, were the urchin fishery is overexploited. As stocks of sturgeon in the Caspian Sea fall near to extinction levels, the roe of the sea urchin is a substitute for caviar on the menus of exspensive restaurants, usually under its Japanese name, uni. The taste is like ""the sea without being fishy", just like caviar or briny oysters." Green sea urchins can be found in much larger numbers and have a much better taste then the edible sea urchin. But they are much smaller, and cost more to harvest. There is a small fishery for edible sea urchin near Scotland and the Scilly islands.
The common sea urchin is variable in color: pink, purple and white are all possible.
Both foto's are made by Jim Greenfield .
Echinodermata, a painting of Theo Carreras, fin du siecle.
1 brittle star
2 echinus escalentus or edibble seaurchin
3 asteria rubens or red or common seastar
4 Neocrinus decorus a sealilie
5 sea cucumber
6 slate pencil urchin, red slate pencil urchin, or red pencil urchin or hererocotus mammilatus, underside
Enemies of the common sea urchin
If sea urchin are young they are eaten by many predators. In the North sea herring is an important one consumer of the young sea urchins. Adult sea urchins are eaten by lobsters and the Nortsea crab. Seagulls have been known to prey on sea urchins when they get the chance.
Echinoderms of the North Sea.
1 Common Starfish or Asterias rubens. (twice)
2 Sand Sea Star or Astropecten irregularis
3 Common Sun Star or Crossaster papposus or Solaster papposus.
4 Common Brittlestar or Ophiothrix fragilis.
5 brittle star or Ophiura albida
6 Amphiura filiformis
7 European Edible Sea Urchin or Echinus esculentus
8 Green Sea Urchin or Echinus miliaris
9 Sea Potato or Echinocardium cordatum