Production planning for our 20 ton tilapia farm begins where we take our 0.5 gram fry into our quarantine and grow them out through the planned stages until harvest. We estimate growth and time for each stage based on the previous calculations we applied in our yearly production (Part 1) and culture conditions (Part 2). Staged production on your fish farm is designed to get the most out of every tank in your system and avoid having any tanks not being used to their full potential. Remember every square meter (or foot) on your farm comes with a capital and operational cost. Finding the sweet spot between practical operations, husbandry and capital expense can be quite difficult. It is here where we define the staging which will determine the amount of tank and with that, that amount of handling the fish will have to put up with. Every farm must have a quarantine stage if fish are bought into the farm from outside. There is some disagreement between aquaculture professionals surrounding biosecurity on your farm is it an essential cost. No argument from me, biosecurity is an absolute must on every farm. To not have those points of control will have very unfortunate affect on the farms viability. Don’t make the mistake of thinking separated tanks are biosecurity. Biosecurity Sidebar: A good friend of mine discovered the value of proper biosecurity on his farm a little too late. He had biosecurity in terms of cleaning stations, foot baths, all the bells and whistles which were inherited with the farm he bought. However, his quarantine tanks were inside his culture room. Meaning any air borne (aerosols) transferred diseases introduced to those tanks will, not might, but will makes its way into your culture tanks and will wipe out your entire stock. As my friend found out too late. Recovery from the cash losses was impossible or impossibly expensive. “Doors close on unclosed doors”. When I see integrated systems with fish tanks in the greenhouse and no biologically separated systems, I shiver. Not only do you have no temperature control, there are no points of control for disease entry. Every farm will experience some disease at some point during production, how far it spreads through the farm is directly related to how well your biosecurity is set up. While biosecurity will not guarantee immunity to disease, prevention while it can be costly, is far better and less expensive than the cure. Not to mention, HACCP certification issues may also be raised. Ok enough said, I think you get the point. We know in our scenario from the previous steps it will take approximately 35 weeks to grow our fish out to 500 grams so we set our overall plan to meet that production time. The tricky part is working out how the staged production will be broken up. This will depend greatly on the species you are growing and how much grading they require through the growth cycle. In our case with Tilapia, they do not need the level of grading like, say Asian Sea Bass, but we do want to grade them at around 100 grams to weed out the runts if there are any. So we set up a simple three stages. The first is obviously the quarantine. Five weeks in quarantine is quite a long time, were a week or two is suitable to, treat the new fish and identify if they carry any disease/parasite before moving into the grow out facility. What I have found is the quarantine will have its own life support systems (eg biofiltration pumps etc.) so it pays to use them to their full potential. This saves some time in the grow out which will reduce the size of the tanks and life support in there. You can most certainly build a much smaller quarantine and run the new fish through quickly, but in a small farm such as this, you will find the trade off on available tank size and management of them to outweigh the cost of running them for longer in the quarantine. This is something you will need to consider. The fish entering the quarantine are extremely small (0.5 grams or 2.89cm) and if kept in the system for a week they would only double in size and be a little bit longer compared to 6 grams and 6.8cm which are much easier to grade out of the quarantine. With such small fish, the outlets in the grow out will be very small requiring regular maintenance and you will want to add another stage to the grow out with much smaller tanks. There is nothing worse than chasing 1 inch fish around in a large tank when shifting from stage to stage. Avoid that if you can and utilize the quarantine life support to its maximum. On the other side of the coin is if you plan to run more cohorts (batches of fish) more often. For example you get new fish in every week, you will need to adjust your quarantine to have the previous fish out the from the week before. Again, in a small farm such as this, getting in new fish every week will add to your buy price of the fingerlings and will add to the management of the fish. You can see we are building a balancing act in every part of the design. Give proper thought to all areas and apply some basic logic to see your operations as easy as possible. Keeping in mind, the quarantine in our scenario determines the harvest cycle of 5 weeks. If we make it shorter we apply a great deal more work managing the farm and again at this size you may find the day to day cost too much. So calm the farm operations down as much as you can. If you were running a much larger facility and you have labor on the farm daily, you can ramp up the staging to utilize that labor more efficiently. Back to the staging. As our fish would benefit from at least one grading after quarantine, we only want to end a stage around the 100 gram mark, grade the fish and move them into the final grow out stage. It is important for your fish and you not to over handle them. Some will not handle very well, even if they require constant grading. Over working your fish will impact on their health and growth so keep it to a practical minimum. You can always grade within a stage if you think the stock needs it. We only have two stages following quarantine and the 5 weeks in quarantine remove 5 weeks of our grow out leaving us with 30 weeks to distribute evenly to be sure all of our tanks are being used all the time. So 2 stages of 15 weeks each works well in our case. It is important to make the staging all divisible by each other or you will end up with empty tanks. Our production planning looks like this. 5 weeks in quarantine, 15 weeks in fingerling and 15 weeks in grow out. Remember this is only for one batch of fish through the system. We will have one cohort entering the system every 5 weeks and one leaving (harvested) every 5 weeks. This five weeks will allow you to harvest 400 kg per week over that period, while you are waiting to clear your quarantine fish, then everything shift up one stage. Example, one tank will be empty, so one tank in the fingerling stage will be graded, culled and moved into that grow out tank, then you will bring in your batch of cleared new fish. The length and weight are estimates calculated from our condition factor and growth per month. These are indicative of healthy fish something you must keep an eye on when in production. You will take weights and measure of your fish quite often to adjust your feed rate, but you will also gain an insight to what condition your fish are in (too fat, too thin, just right). These will be used later to determine feed rates and then further broken down to daily feed applications later in the series. This article is getting a little long and would have liked to talk about the mortality/culling rates. However, as this is an important discussion, we will cover these in more detail in the next part of our series….
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