This will bring them to the same point as the spray dried phytoplankton thread from a little while ago.

I missed this thread, so I don't know if I have anything to offer, but I'll throw in my two-bits anyway...

The spray-dried product has some advantages (primarily cost and storage) and some disadvantages (primarily size and nutritional composition) over live or cryo-preserved phytoplankton. It depends on which animals you're feeding which product will best suit your goals.

The expansion of polyps in response to adding something is *not* necessarily an indication that the corals are getting anything from the food -- this is a common misconception that I see posted -- "the animals respond, so it must be doing something!". Most studies with filter-feeding animals show that they capture and ingest particles of cotton, polystyrene and other nutritionally useless particles flavored with phytoplankton and will often stuff themselves so full of these particles that they can no longer ingest real food when subsequently added. Just because the animals capture and eat something does not mean that they are getting anything out of it.

While Spirulina is high in protein and carbohydrate, it is low in Vitamin C and utterly lacking in the Omega-3 fatty acids that are so important to the nutritional health of most marine animals. The two Omega-3 fatty acids of primary interest are the long chain highly unsaturated fatty acids (HUFA for short) DHA (docosahaxaenoic acid) & EPA (eicosapentaenoic acid) which come almost exclusively from marine sources. The primary source of these essential fatty acids for fish in nature is from phytoplankton and the small things that eat phytoplankton. One of the major breakthroughs in the aquaculture of marine animals was the discovery that these fatty acids were an essential part of the diet, and without them, nutritional deficiencies or arrested development are common problems. For example, newly hatched brine shrimp (Artemia) are a simple and easily cultured food for the larvae (juveniles) of many marine organisms, but because these shrimp lack sufficient quantities of EPA & DHA, most larvae fed exclusively on baby brine die off a few days after they start feeding. The widespread success of culturing and breeding many marine animals has come only since the discovery of the importance of including these fatty acids in the diet. Among the common symptoms reported for EPA/DHA deficiencies are

1. Sudden fright syndrome - shock, convulsion or even death when the animals are frightened
2. poor vision, and reduced ability to locate prey
3. worn or mysteriously eroding fins
4. poor growth rates or sudden massive die offs during early development
5. low egg viability or infertility
6. high mortality and disease rates, particularly when under stress (e.g., shipping or acclimation)

Vitamin C has also been shown to be important to the health of marine animals. For example, growth and survival of milkfish larvae fed unenriched, HUFA-enriched, and HUFA+Vit. C-enriched diets in a variety of conditions indicated that the addition of both HUFA and Vitamin C were important to fish health. The HUFA-enriched fish showed increased growth and resistance to salinity stress over controls, but there were no significant differences between the HUFA and HUFA+Vit. C treatments. The use of Vit.C+HUFA, however, led to significant decreases in the incidence of larval eye deformities over both the HUFA and unenriched controls.

Finally, there are known to be problems with drying algae as a method of preservation and storage. For example, urchins grown on fresh kelp showed the highest growth rates of any trial in tests on artificial urchin diets developed for aquaculture. When the same kelp was dried prior to feeding, however, the air-dried kelp performed the *worst* of any treatment, and the authors conclude that drying algae causes nutritional changes that are ultimately detrimental to the health of the culture animals.

While an appropriate mixture of phytoplankton will provide adequate HUFA and Vitamin C, dried algal powders will not -- therefore, although this may be a convenient and easy way to feed your animals, and although they may gain some benefit from it, there is really no substitute for feeding live or cryo-preserved phytoplankton to your reef.

I would MUCH rather use live phytoplankton, but I don't have access to any.

I agree with you completely on this one, although the frozen stuff is showing the same growth and survival as the live in my lab tests. You should contact Inland SeaFarms . I don't know about the shipping regulations for a frozen phytoplankton product going to Australia, but if it's possible, you could start to market the stuff there. I'd look into it, and then if you can import their frozen phytoplankton, I'd talk to the Reeds about the possibility of becoming the Aussie distributor for the stuff...

New information becomes available, Thursday 17th August 2000.

I have previously posted that until the nutritional information for Spray Dried Marine Phytoplankton (SDMP) was released by the company, there were several reasons to be suspicious of the utility of such a food product.

1. although we have reasonably good expectations of the nutritional requirements of many marine invertebrates, we know nothing of the nutritional value of the product
2. drying kelp and Spirulina leads to significant changes in the nutritional value of these algae to the organisms to which they are fed, and pending testing of the product, there is no reason to suspect that SDMP is any different, and
3. feeding trials with invertebrate larvae I have conducted showed that the product performed very poorly, and in fact larvae fed this product did not develop at all, but rather died at the same rate as sibling larvae maintained in filtered seawater.

Based on these three concerns I have voiced my suspicion of the value of SDMP as a phytoplankton supplement for reef aquaria.

I am happy to report that the nutritional profile for SDMP has now become available, however, and it looks pretty good -- it has a decent amount of Vitamin C (~320 mg/lb) and a good fatty acid profile (of total fatty acids, roughly 24% is DHA, and 0.6% EPA). My initial concerns over the nutritional changes involved in drying these plankton seems to have been unfounded, and a shrimp hatchery has recently reported that larval survival increased to 42% using it at 70 percent replacement level, compared with 23 percent survival using traditional feeds. Furthermore, growth studies by CIAD in Mexico found that SDMP performs almost as well as live phytoplankton for later stages of shrimp development, although not for the initial stages. CIAD obtained the same results I did for early stage shrimp larvae (the product performed quite poorly), but found that after the initial stages of larval development (up to Z1) are fed on live phytoplankton, there is no significant difference in the survival rate or development time to post-larval stage among larvae fed on live phytoplankton and the SDMP product after that stage. The only difference researchers found was that the animals grown on live phytoplankton were significantly larger than those raised on SDMP.

It is worth noting that the shrimp larvae become progressively more omnivorous during this period, and will typically accept rotifers and newly hatched brine as well as phytoplankton. Together with my tests, these results can be easily interpreted as an issue of particle size, and the fact that advanced stage shrimp larvae do perfectly well on the food is not surprising given the particle size obtained by mixing this product. In tests with samples of SDMP I was sent, I found that there was a strong interaction between both the method and duration of storage, and the method of mixing in the particle size provided by the product. I ran some tests to see what effect storage duration and mixing technique had on the mean particle size generated from the product, and the results are presented below.

For size comparison, the average size of phytoplankton cells would be something on the order of roughly 2-9 um in diameter. If you get SDMP fresh from ESV, store it in the freezer, and actually use a blender to mix it for 2 minutes like the directions suggest, you do get a lot of particles in the correct size range. If you get it from the petshop, store it on the shelf behind the aquarium (like I did during my tests) and then (even worse) mix it by hand (as most people do), then the particles come out at roughly the size of rotifers rather than phytoplankton. This particle size issue appears to be the biggest concern with the product at this point.

IMO the best source of phytoplankton for a reef tank remains live cultures (which are available from suppliers such as DT's Marine Phytoplankton Farms & Liquid Life USA), but barring the availability of such products, properly stored and mixed SDMP or cryopastes appear to be viable options...