Sea-urchins belong to the phylum Echinodermata. They are widespread throughout the world’s oceans, warm and cold. Humans were known to consume sea-urchin gonads since prehistoric era (Lawrence, 2007). The gonad is considered delicacies and is mostly consumed in the Mediterranean, and the Western Pacific. Today as fishery products, the sea-urchin gonads have become an important commodity in various countries, such as United States, Japan, Chile, Spain, and France (Keesing & Hall, 1998). Then, the current market demand for sea-urchin products tends to increase, and it is predicted to grow in the future. Unfortunately, after reaching peak production in 1995, the harvesting of wild sea-urchins continued to decline due to overfishing and lack of proper fisheries management (Andrew et al., 2002). However, the world production of sea-urchins essentially comes from the wild, and this activity looks ecologically unsound. Therefore, the practice of unsustainable fishing of wild sea-urchins should be stopped because it can disrupt the balance of marine ecosystems, and it reduces the economic potential of fisheries, and also it can be manage during harvesting time and replaced with aquaculture.
First, over-exploitation of sea-urchins should be banned because it causes ecological damage. Sea-urchins are an important biological agent, and they are responsible for maintaining the health of coral reefs. The depletion of sea-urchins leads to uncontrolled invasive algae growth covering the coral surface thus inhibiting the formation of new coral polyp and limiting total coral growth. In addition, sea-urchins provide a significant contribution to nitrogen cycles in seagrass ecosystems. Sea-urchins eat seagrass leaves in large quantities, but they have a limitation in absorbing nitrogen, so they excrete nitrogen in the form of ammonium in a significant amount. Then the bacteria will turn ammonium into nitrate which will be reused by seagrass. Moreover, sea-urchins are an important food source for marine biotas that live in the seagrass and reef ecosystems. Some predators, such as triggerfish, starfish, wolf eels, sharks hunt and feed on sea-urchin gonads which are used as a protein source to meet their energy adequacy.
Another reason why overfishing of sea urchins needs to stop is that it may reduce coastal community revenues from the fisheries sector. One of the ecological effects of the depletion of sea urchins is to decline the health of coral reefs. Such losses often have a domino effect, not only on the coral reef ecosystems themselves but also on the local economies that rely on it. For example, fishermen will spend more money to buy fuel because they are sailing farther than before. They have no choice because the amount of fish in shallow waters has diminished. Another example is the decline in incomes of local people who rely their lives on collecting ornamental fish. The reduced population of sea urchins caused some species of ornamental fish to lose shelter. One of them is the Banggai cardinalfish which is a popular fish for aquarium display hiding among the spines of sea urchins for protection against predators.
Finally, collection of sea urchin from the wild can be managed by setting the harvesting time. Harvest time of sea urchins can be arranged based on the maturity level of the gonads. Based on the research, spawning season generally occurs in October to December. Therefore, it is better to harvest the sea urchins in June-August. Of course, the harvesting must leave some of the existing population. Another strategy to save the population of sea urchins is by replacing natural sea urchin products with sea urchin products from aquaculture activities. Several articles have reported that some countries have successfully developed aquaculture system of sea urchin, land base or offshore system.