Cultivating Palmaria palmata - Bord Iascaigh Mhara

Chapter 9: Results of tank cultivation trials of Palmaria palmata in
2010/2011 and economic analysis
9.1 Case study: land-based tank cultivation of Palmaria palmata: Summary of results
Trials on land-based tank cultivation were started in August 2010 at the three hatcheries (DOMMRS, MRI Carna
Laboratories, QUB Marine Laboratory Portaferry) and at Cartron Point Shellfish Ltd., Co. Clare. The tank set-up
varied depending on the facilities and equipment available (Table 9.1) but followed the recommendations in
Chapter 8.1 and 8.2. Different tank sizes were used, and growth in both natural and nutrient-enriched seawater
was compared.
Table 9.1 Tank set-up at the different hatchery sites.
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QUB Portaferry NUIG Carna
Laboratories
DOMMRS Cartron Point
Shellfish
No of tanks 8 small 4 large 2 large 2 large
Tank volume 230 L 1000 L 1000 L 1000 L
Tank depth 60 cm 90 cm 90 cm 90 cm
Tank diameter 70 cm 119 cm 119 cm 119 cm
Tank surface area 0.385 m 2 1.112 m 2 1.112 m 2 1.112 m 2
Stocking density 0.8 – 3.3 kg m -2 3.6 kg m -2 3.6 kg m -2 1.8 kg m -2
Flow-through
(turn-over day -1 )
Nutrient supply
17 – 20 times 7 - 15 8 - 9 times 8 - 9 times
Sand-filtered
seawater;
Nutrient applications
2x wrasse effluent
2x natural seawater
Raw seawater +
slow release
fertiliser
Sand-filtered
seawater + slow
release fertiliser
First trials starting in late summer were conducted at QUB Portaferry, using high seawater flow rates, different
stocking densities (0.78 kg m -2 , 1.3 and 1.82 kg m -2 ) and no additional nutrient supply. The biomass
approximately doubled (i.e. about 100% increase) every 14 days over a 2-month period between August and
October without significant differences among the stocking densities (Table 9.2). A maximum yield of 2 kg FW
m -2 14d -1 was achieved at the highest stocking density in September. From October onwards, yield dropped
sharply to an average of 15-20% per 14 days. In contrast, at DOMMRS and Cartron Point Shellfish, yields of
approx. 30% and 40% per 14 days were achieved during November and December 2010. Additional nutrient