modified lung Posted May 5, 2022 Share Posted May 5, 2022 (edited) Because I like to collect from the wild, I come across a lot of Interesting zooplankton. Generally, I discard the ones I can't identify as a viable food source and feed the ones I can to my fish. In the past, I haven't put much effort into keeping any of these zooplankton. Because they're collected from the wild, any culture tends to become contaminated with numerous known and unknown microorganisms. Without closely monitoring what's growing in them, you're not really sure what you're feeding your fish. Well all that's about to change because daddy bought a microscope ... that's me …. I'm daddy. So, for the past few weeks I've been doing a lot of digging for information on some of these zooplankton, mostly various types of water fleas, and thought I'd share some of it. First, note that I've listed the higher percentages of nutrional content I've found. The nutritional content of zooplankton can vary by a large degree depending on the quality of their food source. For example, I found reports of the % protein of Daphnia magna to be anywhere between 42–62%. The quality of the food for water fleas, with the exception of Bosmina, seems to be based on it's phosphorus content which is their limiting nutrient. The quantity of food is also important. Water fleas increase their filtering rate when food is scarce. When exposed to prolonged periods of low feed concentrations, the increased filtering rate can use more energy than they receive from their food resulting in nutrient deficiencies or even death by starvation. Too much food can have a similar effect. Water fleas slow filtering rates when food is abundant, but they also increase grooming activity. When feed concentrations are too high, grooming can speed up to a rate that also uses more energy than the water flea can receive from their food. ...Anyways here are some of the interesting zooplankton I've found: Bosmina longirostris Length: 0.2–0.6 mm 60% protein, 18% lipid, 12% carbohydrates, 6% ash, 4.8 kcal/g Found clinging to plants and detritus. Confirmed food sources in the wild include phytoplankton, bacteria, protozoans detritus, and feces. Can both filter feed and graze particles from surfaces. Mass cultures are rare but have been successful using phytoplankton, snail feces, and animal manure. Chydorus sphaericus Length: 0.3–0.6 mm 70% protein, 19% lipid, 8% carbohydrates, 3% ash, 6.1 kcal/g Found clinging to plants, detritus, and suspended in open water. Tolerant of an extremely wide range of water parameters. Confirmed food sources in the wild include phytoplankton, protozoans, bacteria, and detritus. Midge fly larvae feces has been reported to be important for reproduction. Chydorus is often found to be the major food source of wild fish larvae. Mass cultures are rare but have been successful using phytoplankton and a mixture of yeast, powdered trout feed, and cerophyl (wheatgrass vitamin supplement). Ceriodaphnia dubia Length: 0.4–1.2 mm 54% protein, 12% lipid, 30% carbohydrates, 4% ash, 4.9 kcal/g Found suspended in open water in a way very similar to Daphnia. Confirmed food sources in the wild include phytoplankton and suspended bacteria. Ceriodaphnia are commonly used in toxicity studies and are considered a water quality indicator species by the EPA. Mass cultures have been successful using yeast, powdered trout feed, and animal manure. Cerophyl has been successful as a feed in soft water to medium hard water only. Mixed species of phytoplankton have been successful but isolates of many single phytoplankton species have not. Ceriodaphnia have the highest feeding rates in lowlight conditions but stop feeding in the dark. Multiple daily peaks in feeding rates can be induced with exposure to multiple high/low light cycles a day. Ceriodaphnia also do much better under low feed conditions than most other water fleas. Daphnia magna Length: 1.5–4.5 mm 62% protein, 9% lipid, 22% carbohydrates, 7% ash, 2.5–5.6 kcal/g Found suspended in open water also in a way very similar to Daphnia ...because they are Daphnia. Confirmed food sources in the wild include phytoplankton, suspended bacteria, cyanobacteria, detritus, feces, and even inorganic forms of nutrients such as phosphate when organic forms are unavailable. Mass cultures have been successful using yeast, phytoplankton, animal manure, and waste products from food processing plants or powdered forms of soybean, green pea, and rice bran. Daphnia fed yeast were found to have the much higher nutritional content but much lower growth and reproduction rates compared to daphnia fed phytoplankton. Cyanobacteria fed cultures have similar reproduction rates to phytoplankton diets but only after an intial die off and adaptation period. Daphnia cannot survive on pure bacteria diets but can achieve bery rapid growth and reproduction rates on 50/50 to 80/20 ratio phytoplankton/bacteria diets. Cultures using mixed diets always outperform pure diets. Daphnids do 85% of their feeding in the hours surrounding sunrise and sunset. Feeding rates are moderate during daylight periods and slows dramatically around midnight. Moina macrocopa WHY CAN'T I FIND YOU?!?! Here's some info anyways... Length: 0.6–1.8 mm 63% protein, 18% lipid, 18% carbohydrates, 1% ash, 4.0–4.3 kcal/g Confirmed food sources in the wild are similar to that of Daphnia magna. Moina has been successfully mass cultured with the same feeds as Daphnia. Moina however can be fed fish and canola oils, a higher percentage of suspended bacteria, and cyanobacteria without the initial die off. Moina is being seriously tested by some hatcheries as a full replacement for baby brine shrimp which has resulted in higher reported fry survival rates. This may be because Moina contains higher levels of a few very important essential nutrients for many fish larvae than BBS. Simocephalus vetulus Length: 0.6–2.6 mm 54% protein, 12% lipid, 30% carbohydrates, 4% ash, 3.7–4.0 kcal/g Found clinging to solid objects, especially vegetation. Confirmed to feed on phytoplankton, bacteria, protozoans, and detritus. Can feed by filtration or by scraping algal or bacterial growth off the surface of objects. Bacteria can play a major dietary role. Simocephalus feeding rates are not affected by light levels. Mass cultures have been successful using phytoplankton and biofloc. Brachionus rubens (Freshwater rotifer) [The numbers below are from a non-specific rotifer species] Length: 0.2–0.3 mm 52% protein, 26% lipid, 18% carbohydrates, 5% ash Found in open water, clinging to surfaces or to larger zooplankton such as Daphnia magna. Mass culture has been successful using phytoplankton and yeast. ____________ That's it for now. In the future I'll share some culture techniques and experiments I'm doing for each of these and with greenwater. More species might be added if found. Sources either directly from or from the reference sections of: Physiology of the Cladocera by Nikolai N. Smirnov Plankton of Inland Waters by Gene E. Likens Ecology and Classification of North American Freshwater Invertebrates by Thorp and Covich Moreau A, Dupuy C, Bocher P, Farau S (2021) Morphological, calorific and nutritive characteristics of 656 freshwater invertebrates taxa. Biodiversity Data Journal 9: e70214 Edited August 30, 2022 by modified lung Added journal links 5 2 2 Link to comment Share on other sites More sharing options...
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