Stocking
Once the nursery pond is fully prepared for a new season, it’s time to move newly developed fry to the nursery pond. The fry stage is reached when hatchlings’ yolk sacks have been fully absorbed and they’re capable of surviving on planktonic algae. Most species are dependent entirely on algae until they’re large enough to process more complex foods, so a minimum amount of plankton density must be present, relative to stocking density.
Spawn should typically be moved to the nursery pond in the morning or evening when temperatures are cool, and it’s not necessarily a good idea to move them all at once. A well prepared pond with adequate food density can handle a relatively higher stocking rate, but overall survival rate will decrease with stocking intensity. Be sure to apply a prophylactic treatment to incoming fry to reduce the possibility of infection.
Stocking (transfer) is a stressful process for fry, and resulting shock or infections will increase post-stocking mortality. To minimize this possibility, slowly acclimate your fry to the new water by slowly adding pond water and giving it time to mix and equalize before adding more. Eventually, you can float the container in the pond and tip it to the side so that the fry can freely swim out.
Post-Stocking
Feeding
Regardless of the life stage of your fish, they’ll start consuming available natural food as soon as it’s available. Even spawn grazes voraciously on plankton. This means that supplementary feed for your fry should be provided immediately. Typically, a feed in the form of fine powder is broadcast across the pond surface each morning.
In additional to natural and basic supplemental feed, additional feed rich with protein, carbohydrates, lipids and a full panel of vitamins and minerals is called for. Keep in mind that no artificial feed source can provide a complete diet comparable to natural sources. It’s always best practice to provide a balanced menu of both types.
Environmental Monitoring
In managing any aquaculture concern, strict record keeping is necessary. Changes in products, procedures or equipment should be followed by comparison to performance prior to the changes, to catch changes, whether negative or positive. This information can inform future decisions about potential repairs and upgrades.
Fish Health Monitoring
Thanks to a dependable, optimized environment, cultured fish are generally healthy, even when pathogens are present. Robust health helps any organism resist disease, but acute and chronic environmental stressors can shift the balance in favor of disease when pathogens flourish. If the situation is not quickly remedied and the fish are unable to adjust, active disease will appear. Typically, if effective treatments are administered and environmental parameters are established, fish loss can be prevented. Pond environmental factors and fish health monitoring work hand-in-hand as an important factor in the success of your aquaculture operation, particularly in ponds that are not drained and disinfected through annual dry outs.
