Cultivating Palmaria palmata - Bord Iascaigh Mhara

not clear. In the worst cases, the numbers of spores left on the string are very low (10 per cm, or less) and, if this
occurs, the collector should be discarded or re-seeded.
Light intensity: Light is essential for the growth of Palmaria, and the optimal light levels change as young plants
develop. In its natural habitat, Palmaria grows in the dense shade created by the canopy of kelp fronds and it is
not adapted to grow under high light levels. During the earliest phase of development, Palmaria spores and
sporelings are even less tolerant of high light levels. Therefore, lower light is required during the first few weeks.
For ongrowth, the light intensity can be increased to accelerate the growth of small Palmaria plants. If the
collectors are to be kept in the hatchery for more than 6 months (i.e. for deployment in autumn), an irradiance of
about 20 µmol m -2 s -1 will maintain a slow rate of growth and reduce fouling by more light-hungry competitors.
Maintenance: Tanks should be cleaned and the tank water renewed every two to three weeks. Aeration of the
tanks is essential to supply the growing sporelings with CO2 for photosynthesis and to enhance nutrient uptake. If
fouling organisms start to settle on the culture string and the holding structure of the collector, the collectors
should be gently rinsed with UV-sterilised water and fouling algae may be wiped off the holding structure/frame
with a cloth. Larger algae may be removed individually.
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