Feeding Baitfish Fry

With the spawning season over for the year, it's a good time to evaluate baitfish fry survival and growth. Hopefully it's been a good year and you have ponds full of new fish. If not, you may want to consider some pond management changes.

What's a normal survival rate? In a study conducted in UAPB research ponds, survival from matted egg to juvenile size (called "peewee", weighing 0.5-2 lb/1000 fish) ranged from 9 percent to 47 percent and averaged 24 percent. The losses took place during the egg incubation and fry stage. Research information on survival of hatchery fry to juvenile size is limited and a current study at UAPB will provide additional information. Major factors influencing fry growth and survival are water quality (especially pH in the first week), food availability, predators (such as some copepods and insects) and abrupt temperature changes (as when a cold front arrives). This article is about increasing food availability for baitfish fry.

In nature, newly hatched golden shiner fry are found along the shore in shallow water. As they grow they congregate in schools, and over time, move into deeper water. Golden shiner fry feed on zooplankton which are sometimes free-swimming and sometimes attached to plants and other surfaces in the pond. Evidence from commercial farms suggests that golden shiner fry can thrive even in ponds with relatively low numbers of zooplankters. Early work at UAPB by Morrison and Burtle found that golden shiner fry consume phytoplankton (algae). It is not known if the fry can digest the algae as well, but it is a possible explanation for the observations from commercial farms.

Work in Russia found that the young of two native cyprinids (the same family as the golden shiner) were able to utilize phytoplankton in the absence of zooplankton. Nevertheless, golden shiner and goldfish fry are often stocked at extremely high rates (as compared to the fry of other fish species) up to 500,000 or 1,000,000/acre. At such high densities, feeding baitfish fry with a prepared diet is critically important to fry growth and survival. It has been shown in a study on hybrid striped bass that fry with access to more food grew faster and reacted more quickly to simulated predator attacks.

Newly stocked baitfish fry benefit from being fed a prepared feed in the form of a meal. Fry consume meal directly; excess meal is eaten by zooplankton and also serves as an organic fertilizer. Newly hatched golden shiner fry weigh about 1.2 milligrams, or 400,000 fish per pound, so at 500,000 fish/acre, that is only a little over a pound of fish per acre at stocking. A typical feeding rate is 2 to 5 pounds/acre/day, divided into two feedings a day. In tank culture of goldfish fry, the feeding rate for best feed utilization was found to increase with water temperature, increasing from 35 percent to 70 percent of initial body weight per day as the temperature was increased from 68ºF to 82ºF. In commercial ponds, fry are best fed to excess, rather than on a percent of body weight basis, because feed drifts away from the fry or is lost to bottom muds.

As fish grow, increase the feeding rate up to 5 to 10 pounds/acre/day after a month. Fry will quickly grow, and by seven weeks a pond may contain 200 to 275 pounds/acre of fish (at a size of 500 to 1,000 fish per pound). Feed meal for the first 5 to 6 weeks. Switch to crumbled extruded feed after 4 to 6 weeks, and then to a pelleted feed by 8 weeks.

Many farmers already feed fish in ponds with blowers. However, on windy days, which occur frequently in Arkansas in the spring, a lot of the meal blows away. Because fry hang in a band around the pond edge for the first few weeks of life, delivering prepared feed directly to them will increase growth and survival. UAPB Extension Aquaculture Specialist David Heikes has developed a mealer that applies the feed in a band around the edge of the pond.

 

 

 

Meal is an excellent feed for young fish. However, as fish grow, the feeding rate increases so switch to larger forms of feed - crumbles and then floating pellets. Large amounts of meal causes water quality problems and a good portion of the feed is wasted.

Have you ever thrown a pinch of meal into a glass of clean water and watched? The following picture series shows what happens minute by minute after a teaspoon of meal is sprinkled on top of a cone of water. For comparison, the picture on the left was taken after almost all the meal had settled to the bottom.

As you can see, about one-third of the meal (by volume) settles out of the water within 4 to 5 minutes. That happens in production ponds as well. When fish are small extra feed is beneficial and serves as fertilizer. However, as fish become larger extra feed is no longer beneficial, and leads to water quality problems.