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The Lobster Pond on the left contains the broodstock of fertilised females, known as berried hens (banded to prevent them from fighting). Female lobsters mate in the autumn, and then carry their 20,000+ eggs on the underside of their tails, as they slowly mature. These eggs hatch into larvae during mid to late summer.
After hatching, the lobster larvae float to the surface of the water and tend to accumulate under the lights. At this point we transfer the larvae to the conical bins, which contain swirling and upwelling water. Here the planktonic, mid water stage is stimulated, during which time the lobster larvae molt (shed there shells) four times in order to grow. The stage four larvae (approx 1 cm in length) are miniature replicas of the adult form. In the wild they would sink to the seabed where they would burrow into the mud.
In captivity the stage four larvae are transferred into individuals cells seen here to prevent the tiny lobsters from eating each other. They are fed twice a day on a varied diet, to mimic what they would normally have in the wild: small pieces of mussel, crab, winkle, shrimp, prawn, mysid shrimp and sand hoppers. They are released into the wild after approximately one year. At this stage the lobsters are around 2-3 cm in length, and have a much better chance of growing to maturity.
Our lobster breeding station was set up to combat some of the effects that commercial exploitation has had on lobster populations. Lobsters are a highly prized and valuable commercial species. Drastic overfishing for the restaurant trade, combined with lobster?s extremely slow growth rate, has severely reduced lobster populations in many areas of Ireland. It takes between 5 to 7 years for lobsters to reach maturity, and by this stage they are at marketable size, so many have been caught by fishermen.
Here at Lahinch Seaworld, we enhance our lobster breeding programme in several ways:
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The larvae displayed here were bought in from a hatchery on the Orkney Islands this week. We bought in juveniles at an older age (stage five) as they have a much higher probability of survival at this age. There are no predators to reduce numbers in our system, but the larvae do attack each other so this can limit survival. We avoid this problem by settling them in separate calls so they cannot eat each other.
Hatching and growing juvenile lobsters in captivity ensures that a higher number of them survive. In the wild it is estimated that up to 90% of juvenile lobsters die before they become fully mature. We too have some mortalities in our breeding programme, but we strive to ensure that each juvenile lobster gets the care and attention it would need to survive to adulthood.
Our Lobster Breeding Programme has been a great success over the past few years. Since the programme has started we have released several hundred of our strongest and fittest lobsters into the local enviroment. We hope that these have gone on to help rebuild the local lobster populations. We also aim to educate people on the life cycle and importance of this species.
