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Sea urchins are easily recognisable marine animals. They look like spiny spheres under the sea and they grow to around 1-4 inches in diameter. There are hundreds of different species of sea urchins. Their colour vary depending on their species, but most of them are green, red, purple, black and brown.
They belong to a group of marine animals called echinoderms. The literal translation for Echinodermata is “spiny skin”. Apart from having spines, all echinoderms have radial symmetry. There are claw-like structures on their spines which act as their main protection against predators. Those that feed on sea urchins include sea birds, crabs, otters and humans. Some species of sea urchins have venom on their spikes. This is why there are cases wherein people who accidentally step on sea urchins experience pain, swelling and discomfort on their affected foot/leg.
Sea urchins are omnivores and mainly feed on plankton, algae and sea weeds. They reproduce through external fertilisation like most marine animals. On the average, a sea urchin can live up to 30 years, but one particular species, the red sea urchin, can live up to 200 years.
Sea Urchin As A Delicacy
Decades ago, the biggest market for sea urchins was Japan. This was due to their love for “uni”, which is served raw like sushi. “Uni” is actually the roe of the sea urchins or to be more technically accurate, they’re the gonads of the sea urchins that produce the roe. Apart from being served raw, the roe can also be used to cook pasta. Italians call it ‘Ricci Di Mare’; it is mainly used in pasta sauce.
Some people call them the foie gras of the ocean because of its smooth and custard-like texture. However, much like foie gras, eating sea urchin is not for everyone. Some people find it delectable and there are also those who do not like its taste.
The Rise In The Global Demand For Sea Urchin
Demand for sea urchins globally has dramatically increased in the last couple of decades. In the US, the surge in demand for sea urchins was once hailed as the “Green Gold Rush”. Apart from the primary market which was Japan, the demand in the US has increased greatly. The main reason cited for this was the American palate which was continuously looking for something new. Sea urchins are now expensive and considered as hot-ticket items just like truffles and foie gras.
In a report released by the Icelandic Food and Biotech R&D Institute, Matis in October 2017, they mentioned that the worldwide annual supply of sea urchins peaked in the 1990s at around 120 thousand tons. However, currently, it decreased by more than 35% with supply now at 75 thousand tons. If the trend continues at this rate, the annual supply is going to be less than 30 thousand tons in around 50 years.
In the UK, the demand for purple sea urchins also increased in the past years. Purple sea urchins are considered by some to be the best tasting sea urchins available in the market. They are quite rare, mainly because the supply is unpredictable. According to experts, it is the combination of a very cold sea and the correct type of kelp, the seaweeds that sea urchins eat, which gives rise to this fantastic flavour.
What’s Causing The Decline In Sea Urchin Population?
The increase in demand and the fact that sea urchin exploitation is unregulated in the British Isles have caused a significant decline in the sea urchin population in the UK. While some experts are trying to replenish the population through hatcheries, it still has not been enough to regain what was already lost.
Studies done in previous years have shown that one of the main causes of global warming has also negatively affected the sea urchin population. The continuous increase of carbon dioxide levels in the atmosphere does not only aggravate global warming; it also causes the acidification of the ocean. What’s its effect on sea urchins? The rising acidity of the ocean makes sea urchin eggs more vulnerable to fertilisation by a second sperm. In marine animals, fertilisation by a second sperm is fatal. This has resulted in the decline in the birth rate of many marine animals including sea urchins.
Are Sea Urchins About To Be Endangered?
Statistics show that the economic value of sea urchins is rapidly going down due to the decreasing supply. In Nova Scotia Canada, the annual value of the sea urchin catch has decreased by more than 60% in 15 years. In the state of Maine in the US, the sea urchin industry was once valued at $35 million but is now just worth $5M, an 85% decrease from its peak value.
These figures and the significant decrease in the annual supply of urchins all indicate that the world is consuming them at a much faster rate compared to how much is replenished. While hatcheries, aquaculture and roe enhancement have helped in addressing some of the demand, sea urchins harvested from these efforts account for less than 0.01% of the annual supply. Sea urchins are now threatened and may soon become endangered.
While the acidification of the oceans have also affected sea urchin population, it is clear that consumption is the top reason for the decline in sea urchin population. As such, it is imperative that the global consumption is decreased greatly to allow the sea urchin population to replenish and avoid becoming an endangered species.
Image Attribution: Karachi Scuba Diving Center at the English language Wikipedia [GFDL or CC-BY-SA-3.0], via Wikimedia Commons
Image Resource: https://commons.wikimedia.org/wiki/File%3ASea_Urchins_enjoying_sunbathing.jpg
Purple Sea Urchin
Image Attribution: By Gregory “Slobirdr” Smith (Purple Sea Urchin – Strongylocentrotus purpuratus) [CC BY-SA 2.0], via Wikimedia Commons
Image Resource: https://commons.wikimedia.org/wiki/File%3APurple_Sea_Urchin_-_Strongylocentrotus_purpuratus_(16455860102).jpg