Much of the fish we eat is commercially grown. Are fish more efficient converters of plant to animal protein since they are cold blooded and don’t waste a lot of energy producing heat? How much more efficient?
Great American Food Almanac quoted in Catfish Ponds & Lily Pads by Louise Riotte:
Work is the curse of the drinking classes. (Oscar Wilde)
My uncle is much more qualified than I to answer this (he raises fish for stocking purposes) but I’ll throw a little bit into this. Speed of weight gain is a factor and this is greatly affected by the temperature of the surrounding water. He has a heated recirculating system in his building for the specific purpose of growing fish during the winter months when they wouldn’t otherwise gain were they in an outdoor pond. He gets very good results with this system, mostly with bass and perch this winter.
Anyhow on to a study…
Feed and Water Quality in an Aquaculture Facility
“On average each participant in this survey had tried between two and three different brands of feed. These figures do not count the different varieties tried within a particular brand.
Most producers (87%) indicated that they did not know what their feed conversions rates were. Aquaculture producers knowing and reporting their feed conversion indicated that feed conversion averaged 1.29:1. For Purina the feed conversion rate was known by only 25 percent of the users of this feed. The average reported conversion rate was 1.1:1, with a range between 1:1 and 1.2:1. Only 23 percent of the producers using Southern States feed reported knowing their feed conversion with that feed, with the average being 1.2:1 and ranging between 1:1 and 1.4:1.”
There is quite a bit more material at this site. Your best bet is to search for individual feed conversion rates for each specie.
Hey, thanks for the info on fish farming. Its really amazing how efficient fish are. It seems to me that we should be encouraging people to eat more fish on top of the proven health benifits.
I have been raising cattle and catfish for 23 years. Average feed conversion ratios for cattle are 5-7 lbs feed = 1 lb beef. For catfish the figure is 2-1.
In response to the question about keeping warm, during the winter the fish’s metabolism slows down drastically. One feeding in the winter will last them for a week or more. In the summer they eat every day.