- Effective at all life stages – larvae, setting, spat, fattening and maturation
- Effective when used with open tanks, silos, bottle upwellers, header tanks (with circulation), cultch tanks and depuration tanks
- Works best when there is moderate circulation to keep the algae suspended
- Freshwater applications - Shellfish Diet is an effective feed for freshwater as well as marine organisms. Shellfish Diet and other Instant Algae products are widely used in freshwater mussel research.
- Other uses of Shellfish Diet - Shellfish Diet is an effective feed for a wide range of filter feeders including bivalves, crustaceans, corals, and sea cucumber larvae
Feeding with Shellfish Diet
- When feeding into open tanks or header tanks pre-dilute the algae 10:1 with seawater
- We suggest pouring the slurry through a 20 to 50 micron mesh bag to ensure algae are dispersed
- When water is circulated with a centrifugal pump, such as with an upweller or downweller, Shellfish Diet can be added in front of the pump intake and the pump will disperse the algae cells
- Do not use a blender to mix the algae!
- Store refrigerated at 0 - 4°C
- Use within 4 weeks of opening
- Shelf life of 18 to 24 weeks when unopened
- Do not freeze (see related product LPB Shellfish Diet)
Automated feeding for convenience and regulation of food density
Dispensing feed at frequent intervals makes it easier to maintain a steady food concentration in the culture tank, avoiding both overfeeding and underfeeding. A peristaltic pump, controlled by a timer, may be used to automatically dispense Shellfish Diet into the culture tank Shellfish Diet should be pumped from a reservoir housed in a refrigerator or ice-water bath. Experience has shown that the residence time of the feed in the tubing that delivers the feed to the culture tank is so short that this brief exposure to higher temperatures has no adverse effects on the quality of the feed.
A wealth of information on bivalve culture is available in the FAO's manual "Hatchery culture of bivalves", available as free download (be sure to download using the "ZIP" option, otherwise you will not get the complete manual). The following feeding rates are based on the FAO recommendations.
The following feeding rates are based on the FAO recommendations...
Larviculture may run up to 20 days, but maximum feed is 20 mL/day/million larvae because there is no growth beyond 300 µm. Setting can be delayed if larvae are fully developed but do not set because they don’t detect suitable setting conditions.
Daily Feed Rates per million larvae, for Crassostrea virginica (from FAO protocol)
||Mean Shell Length
||Billion cells of Isochrysis per million larvae
||Liters of Live Isochrysis at four million cells per ml
||ml of Shellfish Diet 1800 or Isochrysis 1800
Feed By Live Weight:
– OR –
Feed by Seed Count:
(Feeding 1 million Oyster Spat; based on FAO manual, p. 137, Table 14)
||Shellfish Diet feed per day
Feeding Broodstock (Conditioning) and Fattening Shellfish for Market
The required food ration for conditioning is based on the meat weight of the adults. It is usually between 2 and 4% of the mean dry meat in dry weight of algae fed per day. This is approximately equivalent to 0.03 – 0.06ml Shellfish Diet per gram of wet meat weight.
Typical Broodstock feed rates:
0.03 ‐ 0.06 ml Shellfish Diet per gram wet meat weight per day
– OR –
0.3 – 1.2 ml Shellfish Diet per adult animal per day
Batch Feeding - Dispensing Shellfish Diet
Shellfish Diet can be poured directly into the culture tank with stirring, but pre‐dilution is preferred.
Because Shellfish Diet is so highly concentrated, sometimes cells may form clumps when the feed is added directly to seawater, due to interaction of extracellular polysaccharides with polyvalent ions such as calcium (cf. gelling of alginate). An initial dilution (e.g., 1:10) with fresh water (free of Ca++ or Fe+++, which can also cause gelling), or even better a NaCl solution (typically 30 g/L; concentration is not critical), ensures that the cell‐to‐cell separation is great enough that cells cannot stick together when they are mixed into seawater. It also helps to pour the diluted feed through a 20 µm mesh filter—there is negligible retention on the mesh, and it ensures that dispersion is complete. Stir to mix feed; DO NOT MIX IN A BLENDER.
Automated feeding for convenience and regulation of food density
A peristaltic pump, controlled by a timer, may be used to automatically dispense Shellfish Diet into the culture tank. Dispensing feed at frequent intervals makes it possible to maintain a steady food concentration in the culture tank, avoiding both overfeeding and underfeeding. Shellfish Diet should be pumped from a reservoir housed in a refrigerator or ice‐water bath. Experience has shown that the residence time of the feed in the tubing that delivers the feed to the culture tank is so short that this brief exposure to higher temperatures has no adverse effects on the quality of the feed.
Dilution of the feed is particularly advantageous when it is dispensed by pump:
- The increased volume reduces feed viscosity, so pumping is easier.
- The increased volume requires faster pumping rates, which helps prevent the feed from settling in the lines.
- Higher pumping rates are easier to measure and regulate (more difficult to precisely pump very small volumes).
The only disadvantages to dilution are the need for a larger feed reservoir, and the need to continuously stir the feed, because the reduced feed viscosity cannot maintain the algal cells in suspension. Some users stir the diluted feed with aeration or magnetic stirrers, but we found that a mini submersible pump (such as used in small aquariums or decorative garden fountains) is very cheap, reliable and effective. Their power consumption is typically 3 watts, so they contribute insignificant heat.
Shellfish Diet is an effective feed for freshwater as well as marine organisms. Shellfish Diet and other Instant Algae products are widely used in freshwater mussel research. Because the algal cells in these products are not living their cell membranes are not osmotic barriers, so the cells are not subject to swelling in fresh water.
Other uses of Shellfish Diet
Shellfish Diet is an effective feed for a wide range of filter feeders including bivalves, crustaceans, corals, and sea cucumber larvae.
Feed rates for bivalves
(see also here: Feeding Shellfish with Instant Algae)
One of the greatest advantages of feeding Shellfish Diet in place of phytoplankton cultures is that this feed provides a known concentration (dry weight) of food, whereas phytoplankton cultures normally must be monitored and frequently quantified (usually by cell counts) so they can be fed out at controlled rates. The simplest technique for feeding shellfish is by monitoring water color; add a dose of Shellfish Diet to the culture tank and watch how long it takes for the animals to clear it. If they clear it in less than 60 minutes, feed more, etc.. To obtain good growth, juvenile and adult shellfish should be fed at least is 1‐2 times each day, while for maintenance feeding can be as seldom as once per week.
Dry Weight vs. Cell Count
We specify the concentration of our Instant Algae products by biomass dry weight (Shellfish Diet is 80 g/L dry weight), not by cell count. There is such a large difference in cell volume (and biomass) for a small difference in cell diameter (volume is a cube function of diameter) that cell number is not a reliable measure of food value.