Science Centres: Fisheries

 

The layflat bags at Bream Bay. (Photo: Ian Cameron, NIWA)

A recently installed continuous algal production system utilising state-of-the-art technology is now supplying microalgae to one of NIWA’s onsite clients at Bream Bay, Sealord Shellfish Ltd.

The unit, which is called a layflat bag system, consists of 20 x 1500 litre polyethelene bags into which nutrients and pasteurised seawater are constantly injected. The bags are inoculated with a variety of microalgal species which rapidly divide and build up to a density of 3–4 million cells per millilitre.

The harvested algae is supplied to Sealord’s production unit, where it is used to feed greenshell mussel broodstock and feed the subsequent spat ultimately destined for ongrowing on lines in the Sounds. Jon Bilton, Sealord hatchery manager at Bream Bay, is pleased with developments: ‘Once the layflat bag system was up and running, the reliability of supply to our spat rearing tanks was vastly improved and we are able to confidently feed larger numbers of juveniles, without the boom and bust cycles inherent in batch cultures.’