FEATURE
Live feed production The bottleneck for shellfish, marine finfish and shrimp hatcheries
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by Industrial Plankton, Victoria, Canada
ndustrial Plankton is a Canadian company manufacturing live feed equipment focused on biosecurity and automation. The equipment stabilises hatchery yields by increasing the predictability and reliability of on-site live feed production. To handle biosecurity, the 1000L algae photobioreactor shown here is automatically cleaned and sterilised between culture runs using an internal spray cleaning system and biodegradable detergent. Air is micron filtered as it enters and exits the sealed tank. Incoming water is micron filtered, then UV sterilised at the point of entry, and a peristaltic pump is used for the automated harvest. The harvested algae is ideal for feeding shellfish larvae, spat and broodstock, providing greenwater for shrimp and marine finfish hatcheries, or providing feed for zooplankton. The large volumes produced also make a great inoculant for larger tanks or raceways. Stable culture parameters achievable through automation are also important for biosecurity. Large fluctuations in water temperature, nutrient availability, light levels, and other factors, can cause a portion of the algae culture to die off. The decomposing cells spike the total organic carbon (TOC), creating an environment that encourages the growth of early colonisers, often pathogenic bacteria like vibrio, the most common and
serious pathogen in fish and shellfish marine aquaculture worldwide (Chatterjee, et al. 2012). Despite efforts to maintain biosecurity in the algae room, pathogenic vibrio species can often be found in algae bag cultures, and even in stock cultures at aquaculture hatcheries (Elston, et al. 2008). A 20L carboy is an ideal starter culture for these bioreactors, which the control system will scale up to the full tank volume in seven to 10 days. Once full, harvest is done continuously by overflow, or periodically using the onboard peristaltic pump, with water and nutrients added automatically after each harvest. Alternatively, the whole tank can be harvested as a batch. The optical density sensor can be used to fine-tune the culture’s production. To boost the productivity, a specially designed tank is used to double the surface area exposed to light, letting cultures grow denser before self-shading limit cell growth. In 2016 Industrial Plankton released an automated 1250L LED algae bioreactor for aquaculture hatcheries, as a follow on product to its original 1000L reactor. The 1250L is ideal for continuous diatom production, which is traditionally challenging for even experienced algae producers. A touchscreen gives operators control over the various parameters, such as nutrient addition rates, light levels, harvest density, etc. The data is graphed in real-time, and logged for later analysis to help operators optimise their production.
20 | September 2017 - International Aquafeed