does anything eat sea urchins?

Question

i wanna know,,,,,,,,

Answer 1

Various fish and starfish including some rays. And humans, they are very popular in Europe.

Answer 2

Yes. But do sea urchins eat anything?

Answer 3

Large trigger fish, parrot fish,cod fish, humans(especially asian eat the roe(eggs)), sea otter love them, starfish,crabs, sea birds, lobsters and fox(when washed up on shore).

Answer 4

Sea urchins are solitary animals that may live in loose groups. They are generally spherical or globose (“regular urchins”) but may be flattened into a biscuit-like shape (“irregular urchins”). The general body surface of sea urchins is dominated spiny protuberances of their internal skeleton. The tube feet are also located on this surface among the spines of sea urchins. Sea urchin tube feet have suckers at the tips and are used for locomotion and feeding. Sea urchins tend to be black but do occur in a range of other colours including purple, brown and white. Echinoids walk using their tube feet and their spines in order to gain leverage off the substrate. In some species, like the pencil sea urchin (Phyllocanthus sp.), spines are the principal means of movement. The spines of this species are commonly found among the gravel of beaches on open coastlines in NSW.

Where do they live?
Like most echinoderms, sea urchins are found in all oceans from the equator to the poles. They are also regularly collected from deep in the oceanic trenches. Also like other echinoderms, they are found in truly marine waters and are usually absent in estuaries, as they cannot control the amount of salts in their body (i.e. they cannot osmoregulate). Most urchins hide in crevasses by day and come out at night to feed. Some urchins differ from this general pattern. Irregular echinoids like sand dollars (e.g. Dendraster excentricus) have a limited degree of movement and spend most of their time half-buried within the sediments. Heart urchins burrow through the sediments and are completely buried most of their lives.

How and what do they eat?
Echinoids feed in two main ways. Regular echinoids graze on macroalgae like kelp (as above). Irregular echinoids deposit feed, either by waiting for particles to settle on their body surfaces or by directly ingesting sediment as in the heart urchins. Sand dollars feed by collecting particles on their body surface and by transferring these to the ventral mouth using their tube feet. Echinoids are very important ecologically as grazers. Ecologists at the University of Sydney have demonstrated that areas called “Barrens” which occur between stands of the kelp Ecklonia are due to echinoid grazing. Manipulative experiments in which echinoids were removed from some areas have revealed that Barrens disappear when echinoids (principally Centrostephenus rodgersii, shown above) are removed. Because the sea urchins are no longer there to eat the kelp, the kelp grows over the barren areas.

What eats them?
The spines of sea urchins make an impenetrable barrier for potential predators. Several fish, however, are known to prey on sea urchins (e.g. large trigger fish and wrasses). Human predators have an important impact on urchin populations with ripe gonads being a popular food item in a number of European, Pacific and Asian cultures. A range of other factors affect sea urchin survival. In the late 1980s, a suspected viral agent led to a massive reduction of sea urchin numbers in the Caribbean (Hughes et al. 1987). After the sea urchin die off, reefs that were mostly coral were replaced by reefs largely dominated by macroalgae.

How do they grow and reproduce?
Sea urchins generally have separate sexes and spawn seasonally every year. Eggs and sperm are usually released to the water column where fertilisation occurs. Development of the young involves several larval stages (i.e. indirect development). The first, an echinopluteus larva, looks like tiny shuttlecock. After 20-40 days, the echinopluteus settles and turns into a juvenile sea urchin. There are other ways that sea urchins develop. Their larval development is actually quite varied with a range of different developmental options being shown within the group. · Planktotrophic: develops via a feeding larva. · Lecithotrophic: develops using energy reserves contained with the egg. · Brooding: develops using energy reserves contained with the egg in a pouch or protected space within the maternal body.

Who do they live with?
There are a number of interesting symbionts and parasites that are found in association with echinoids. Polychaete worms and fish (e.g. cling fish) seek refuge within the spines of echinoids and may contribute to cleaning the surfaces between the spines which act somewhat like a sediment trap.

Their connection with people.
Some species of sea urchins are poisonous and they should generally be treated with care. One species, Toxopneustes pileolus, has large cup-shaped pedicellariae (special pincer-like spines) that are very poisonous. Sea urchins also have a commercial value – they are eaten by a wide range of cultures around Asia, Europe and the Pacific. This has lead to some worrying declines in sea urchin numbers around the world. Because they are so important ecologically (e.g. controlling the amount of sea weed on reefs), these declines have made some scientists think that changes on reefs may be related to the fishing pressure on sea urchins and other species.