Lobster Hatcheries – Sow Before We Reap
January 27, 2016
Todd Fisheries Technology is committed to helping create Sustainable Fisheries.
Our mission is to have hatcheries all around the UK coast helping to guarantee the future of the commercial shellfish fisheries.
A female lobster lays eggs or berries under her tail. She can have between 4,000 to 40,000 eggs depending on her size. The larger the lobster, the more eggs she can carry. Perhaps more importantly, the larger the lobster, the larger each egg is and this gives the hatched larvae a higher chance for survival. These eggs take about 9 months to hatch (depending on sea temperatures) and turn from black to purpley red to green.
When they hatch, the larvae float around in the plankton and catch their food. They are most vulnerable at this stage as they cannot escape predators and can be easily damaged. To grow they moult their shell and after three moults (about 2 – 4 weeks) they settle out on the sea floor. At stage four they face another challenge because as well as other predators they become canabalistic and will eat one another. They need to find shelter and food to enable them to grow to an adult lobster. They can be caught once they reach 87mm carapace length (measured from behind the eye to the base of the start of the tail). Only 0.01% of eggs survive to adulthood. This is a very poor return to the fishery.
I’m sure it will surprise most readers who are not fishermen to know that it is not illegal to catch or sell a berried female. Most of the fishermen we work with however know this would be daft and always return them to ensure a fishery for tomorrow. Although we are focussing on hatcheries in this blog we are also advocates for other improvements relating to the shellfishery, e.g V-notching etc., but more about that another day.
A Lobster Hatchery works by bringing the berried females into a land based aquatic recirculation system and raising the juveniles to between stage 4 and 7 before releasing them back to the fishery. This ensures a much larger return to the fishery with on average an 80% survival to this stage and an 11% return to the fishery (much more than the 0.01% in the wild). The tanks are designed to optimise each stage of growth and development and the diets are managed to ensure they are healthy, strong and environmentally fit.
A traditional hatchery could cost over £1,000,000 capital costs and return up to 24,000 juvenile lobsters per year. We are proud to have developed new technology which can be purchased for between £50-120,000 depending on the size of hatchery and raise hundreds of thousands of juveniles. More about our technology and ideas for multi-species hatcheries in future Blogs.