Industry and researchers in Japan have recently made promising breakthroughs in full-cycle, land-based farming of oyster and eel, both species notoriously difficult to raise from larvae to market size. The Tokyo-based producer General Oyster had been faced with declining productivity in raising oysters in inshore operations due to warming waters and shrinking availability of healthy (non-poisonous) plankton to feed oysters, both problems caused in part by climate change. So, the company invested in a world-first on-land oyster farm, which is supplied with offshore water (from depths of 200+ meters) that is free of viruses and bacteria. In addition, algae for oyster food is now produced separately, using mass cultivation technology. The operation is still at an experimental stage but shows promise because onshore farms allow greater control over the factors influencing oyster growth and product quality.
The latest news for eel full-cycle farming is even more exciting. Eels are famously hard to farm full-cycle, as European aquaculturists know all too well. From birth to death eels do not simply grow, they undergo a multi-stage metamorphosis from larvae to adult, and then undertake a long migration to spawn, experiencing conditions which are difficult to artificially reproduce on a farm. Enter Japan, where eels traditionally have been farmed (more accurately “ranched” after capture as young eels) in the usual way from slender glass eels to nice fat adults ready for market. Japanese eels, like European eels, are on the IUCN (International Union for Conservation of Natural Resources) Red List of threatened species, and their scarcity is turning kabayaki, or grilled eel, from a traditional dish to an expensive luxury. But a different way to farm eels is emerging thanks to research by specialists at Kindai University’s Aquaculture Research Institute (which has already developed techniques for full-cycle farming of tuna).
In the summer of 2023, the university’s researchers announced that they managed to successfully raise eels from larvae all the way to adults in an onshore site. The commercialisation of this technological advance will not be immediate, however. Early in their lives farmed eels need large volumes of expensive fish meal treated with enzymes. Costs for labour and complicated temperature and quality control systems are also high, making entry into this new segment of the industry risky for now. But many had said tuna would never be farmed, too.