What are You Feeding the Fish? – Best Feed Choices!

Aquaculture may be a very water efficient way of producing animal protein but it is not without its problems. In particular what the fish farmer feeds their fish is a big issue.

We had a great weekend at the Melbourne Sustainable Living Festival Big Weekend. Thanks again to all that made it possible.!

We met lots of people and were asked lots of questions. I will answer them over the next few days and the first one is today: What are we feeding the fish?

I love detail and I tend to like to explore issues in depth. All too often there are no simple answers and often the best answer is: “It depends!”. So a format I’m going to use when answering questions is the following: Short Answer/Long Answer. This allows people to skim through and get an overview, but also to learn about the subject in detail. Here we go:

Short Answer

We will be feeding the fish commercially made pellets manufactured by Skrettings, in Tasmania. We would like to use an organic feed, but there is none available at this point in time. We have been talking with a new innovative feed manufacturing startup based in QLD. They have developed a new technology modular technology that allows them to establish small manufacturing operations to tailor to local demand., They are also able to utilises a range of different feed stocks that can reduce the amount of fish meal and oil in the fish food even further than currently possible. As we have encountered ourselves and heard so often from other startup teams, this manufacturer needs signed contracts from buyers of their food in order to unlock funding to get their operation started. They are hoping that we will be able to do this for them, once we have our own operations up and running.

After Fish Farmers has established a significant market presence we will use our market position to try and shift market demand away from carnivorous fish to more sustainable omnivorous and vegetarian fish species. Some people will always want their carnivorous trout, salmon, barramundi or murray cod. Others will appreciate more economical and sustainable choices that Fish Farmers will offer environmentally minded eaters.

Long Answer

Feeding fish on a farm is one part of a complex system to produce fish and in our case plant crops as well. Many other parts of the operation determine the overall environmental footprint. While choice of feed is an important part of an aquaculture operation that wants to be called “sustainable” its not the only consideration.

I first started to look at drought proof farming methods over ten years ago. It quickly became apparent that current drought proofing techniques create substantial environmental impacts, particularly because of the amount of energy they consume. Aquaculture was a method that quickly got my attention because I saw that there was an alternative way to drought proof fish farming. An alternative that didn’t rely on the massive consumption of fossil fuels. As counter intuitive as it appears, the fish themselves do not actually use much water and because it is not the fish using the water its actually quite easy to drought proof fish farming. In reality it is the farmer that is using the water to flush waste from the fish out of the farms ponds and raceways, just like a dairy farmer uses water to hose out their dairy.

I’ll talk about this more below but I want to start with the feed. While a lot of work is being done by the industry to reduce the amount of wild caught fish in aquaculture feeds the issue is still a challenge.

Believe it or not but the emerald green water in this picture represents ideal water conditions for fish farming. Managing ponds to ensure a constant algal bloom is one of the most difficult aquaculture techniques to get right consistently.

Alternative Fish Feed on Farms

Farmers using aquaculture intend to reduce their impact and are generally considerate of the production cycle form start to end. So the dependency on fish-feed with a high proportion of wild-caught fish is a problem that the industry has been working to fix for years. When I first started researching aquaculture I immediately wanted to find an alternative feed source but before striving to change something, I set out to understand the reasons for the current situation.

There is in fact an established aquaculture technique that is already independent of wild-caught fish. This technique is called Green Water Aquaculture. It is an excellent method that is more about farming algae and zooplankton than fish.. However the reason this method is not more widely used is that the system is vulnerable to fluctuations and very difficult to consistently run successfully. In this way it resembles more an arcane art than a reproducible production method. It is not often recognised how highly skiled an occupation farming is but Green Water Aquaculture is a whole other level of difficulty. Furthermore, the necessary ponds with large surface areas are not drought proof and therefore not a suitable farming technique for most of Australia.

However, the hope of wild-fish free production encouraged me to learn about fish nutrition and fish food manufacturing. I already new a fair bit about farming insects from my research on the social behaviour of cooperatively breeding like huntsman spiders. I re-visted the farming of meal worms, crickets, silver fish, termites, algae, azolla, black soldier flies, duck weed and a whole stack of other potential food sources. What I quickly learnt was that it is a lot more difficult to feed fish than other livestock. While many of these sources of food have great potential for feeding to fish, keeping fish health high is no simple task using such foods.

For example: Black Soldier Flies (BSF) have an amazing ability to process (agricultural) waste into usable food. They even self-harvest themselves in well designed culture vessels by crawling out of the feed pile along gutters and into buckets. The problem lies in their body composition. They contain too much fat. So much fat that I was once asked to be part of a project that was going to grow the BSF larvae as a feedstock for bio-diesel with the surplus/waste protein to be used for fish food. Trout love eating BSF larvae and other insect larvae, but they contain such high amounts of fat that the trout can develop liver disease quite quickly. Furthermore, if a mixed diet of diverse insect larvae is fed, faster individual fish may predominantly feed on the preferred and fat insect larvae, leaving the remainder for smaller and slower fish. As a result all the fish are not getting a balanced diet. This, in turn, will impact negatively on fish production. This drop does not only affect the productivity of the aquaculture operation, but also the environmental footprint of the operation as a whole.

Skrettings, Fish Farmers current fish feed supplier, produces feed containing about 23 % of wild-caught fish components. Some of these come from by-catch and the trimmings of fish processed for human consumption. The purpose wild-caught fish they use consists what they call “forage fish” which are not widely used as a fresh fish for human consumption. Furthermore, these foraging fish are not the large predatory fish like tuna, which are under threat through human fishing. Skrettings are investing substantially in reducing the environmental footprint of their products, but currently they still need to use some wild-caught fish. Commercially available fish foods in general are designed to cater to the fish growth stage and dietary needs, ensuring a balanced diet throughout their life. Alternative feeds therefore, in whole or in part, can be seriously counter productive for fish health and growth, because it changes the carefully balanced diet of the fish. The drop in health through alternative foods does not only affect the productivity of the aquaculture operation, but also the environmental footprint of the whole operation.

At Fish Farmers, we are striving to produce more with less, using methods that keep the environmental footprint as low as possible overall. Thus the adverse effects on productivity and efficiency using alternative food sources to wild caught currently still outweigh the advantages. It was with some regret that I put researching alternative fish foods ‘on ice’, because I realized there were bigger and lower hanging fruit to be had in solving the engineering problems of integrating aquaculture and hydroponics first.

That leaves us using the feed from Skrettings – for now.

Fish Feed loss and Feed Conversion Ratio

Unfortunately, not all feed in fish production ends up being eaten by the fish and turned directly into growth. A metric that is used to asses the performance of an aquaculture operation is the Feed Conversion Ratio or FCR.

The food conversion ratio should reflect all feed delivered to the aquaculture operation, divided by the overall weight of all fish harvested*.

The smaller the Food Conversion Ratio number the better. A small FCR means less feed is needed/purchased to produce 1 kg of fish. In other words, a highly efficient operation requires a low amount of food for fish production, while an inefficient operation requires higher amounts of feed delivered to the operation.

Since only the harvest weight of the fish is counted any premature deaths or losses reduce the total mass of fish harvested and hence increase the ratio. The FCR is a measure of management as much a fish performance. Which is why the Denmark government requires their Trout farmers to achieve an FCR of 1 or better! If they don’t they risk having their license revoked. In Denmark the trout industry is heavily regulated and in order to comply with those regulations farm mamangement has to be incredibly good. So good that FCRs of less than 0.9 are regularly achieved and some farms report FCRs as low as 0.79. Although Denmark is not the only country to have operations that perform this well it is the only industry that is regulated to have to perform this well or else.

A whole range of factors effect the efficiency with which an aquaculuture operation uses fish feed to convert into harvestable fish. These include factors associated with

• food storage (eg. spills, vermin, rot);

• operations (eg. care during feeding, feeding regime, right selection of feed)

• fish metabolism (eg poor health/stress, genetics

One of the major causes of a poor FCR is poor water quality leading to fish stress, slower growth rates and lowered immune systems. Good animal husbandry means that the fish not only eat well but grow well. The water quality in sea cage, pond and raceway systems is not always ideal. In other articles I explored effects of poor water quality on fish farming and it affects the FCR as well. Fish are under stress when water quality is low, be it low oxygen, high temperatures or other properties of the water. Even in sea cages water quality can be a problem, which is why Huon Aquaculture executives allegedly were concerned about their own operational waste in the water adversely affecting their farmed fish. This despite their earlier assurances to the public and government that their operations wouldn’t have a significant negative impact on the environment. No surprise really considering the history of sea cages in other parts of the world such as Canada, Norway, Scotland and in fact anywhere where cage culture is practised. The impact of – essentially – the indiscriminate dumping of feed and waste into the ocean can be massively harmful. For the purpose of this article and the feed comparison, however, we leave the environmental impact of fish feed and unprocessed and undiluted fish wastes on the water bodies adjacent to fish culture aside. However, the fact that we turn our fish waste into a resource to feed our plants is part of the reason why we are more sustainable than the mainstream aquaculture industry.

So what was the FCR used in Skrettings calculations? Turns out its a whopping 1.5. Why is Skretting using an FCR of 1.5 when Denmark mandates that their industry must have an FCR of 1 or less. Why the difference? Well a part of it is that in sea cages it can be very hard to efficiently manage fish feeding. Another part of it is that small fish grow more efficiently than large fish and largely what Denmark produces is relatively small plate sized fish. What is left is management is mostly management.

Trout farms using the standard methods in sea cages off the coast of Tasmania or in flow through systems besides rivers in Victoria or New South Wales tend to waste more than a little bit of food. In a murky pond its very hard to see if the fish are eating all the food or not especially if you use a sinking rather than floating pellet. In a sea cage it is not uncommon for a portion of the food to get swept out of the cage before it can be eaten.

Low water quality affects the ability of the fish to convert food to growth and weight gain. Furthermore, some fish may get sick and even die. The overall harvested fish weight, however, is one out of the two figures determining FCR. The less weight an individual fish gains and the fewer fish are harvested due to deaths, the higher the resulting FCR will get. Fish that are not growing at optimal water quality and health therefore cause a higher FCR. All of those management issues either don’t apply to tank based systems or are much easier to manage in a tank based system. For starters the water is crystal clear. You can see the fish, you can see them going after the food which is why I believe hand feeding is such an important practice for a fish farmer. Otherwise its all too easy to not notice that something is wrong with the fish. Many big farms install automatic or robotic feeders but the removal of the farmer from fish carries with it many risks. This is another reason why I really think Employee Ownership has a big role in operations like ours. Instead of just the “owner” being the farmer every employee is a farmer not just a labourer or employee. When we share not just the revenue of the operation through wages but also the ownership, profit, growth and most contentious of all control with employees it helps to ensure their motivation and continued diligence. This makes for not just more sustainable operations but also more profitable. On many large scale Aquaculture operations a feed spill is annoying, something to clean up, something the management is going to chew you out over. In an operation where the employees own a significant share of the operation a feed spill represents lost income, lost value, of not just the value owned by share holders but the employees as well since they are shareholders. In such an operation it is very easy to foster a culture where not just feed is managed well but the entire operation. Spills basically don’t occur and food is not merely dumped in the tanks but lovingly fed to the fish and their health assessed with each handful.

We use less food to grow more fish.

Further more there are a range of management techniques to improve FCR that are not practical in ponds or cages that we can use in our tanks. For example more frequent and effective grading separates big fish from little fish. By keeping the size of fish relatively uniform in the tanks. Separating size classes means that the big fish don’t get to monopolise the food and both big fish and little fish don’t waste as much energy chasing each other around the tank. We can also tailor the feed, the feeding regime and the feeding amount to the fish which means that again we use less food to grow more fish.

However, there is only so much we can do and carnivorous fish like Trout will still need to have a substantial part of their diet sourced from wild caught fish for the foreseeable future.

So how much wild fish do we need to produce 1kg of farmed trout?

Skrettings state that with their feed, about 1.9 kg of wild caught fish is used to produce 1kg of farmed trout. This ratio looks astonishingly low, but bear with me as we unpack and analyse that figure for Fish Farmers production.

Due to the issues with cage, pond and raceway systems outlined above Skrettings use an FCR of 1.5 for their calculations. For the purposes of our business planning we have used an FCR of 1.2. If we translate the figures provided by Skretting that would mean we are feeding our fish 1.5kg of wild fish to produce 1kg of farmed Trout. However, business plans are conservative and our real FCR is more like 1. Unfortunately that still means we would be feeding 1.25kg of wild fish to produce 1kg of farmed trout. Even once we get as good as the Danes and get our FCR down to 0.8 then we are still using 1kg of wild fish to produce 1kg of farmed trout. Not good.

How then can you claim to be sustainable?

Sustainable is really a poorly used word across society. What we really mean when we say sustainable is less damaging than what ever else we are currently dissing. Saying some thing is “more sustainable” would be better while “less environmentally damaging” would be better still. Its not as snappy though.

Wind, Solar, Hydro are great technologies that are way less damaging than using fossil fuels  but they are not without their own adverse impacts. Everything we do has an impact so being truly sustainable is often beyond us. That is why our mission at Fish Farmers is just be better than the alternatives. A lot better but not perfect. Just like solar panels our systems have their impacts but just like solar panels are footprint on the earth is much gentler and much smaller than the main stream technologies that we are seeking to replace.

Be the change you can be until you can be the change you should be.

If you have gone through the website you will know this already. Water is the number one limiting factor in agriculture. Drought proof farming and the ability to continue producing food when water is scarce is already possible. Farmers (virtually none) and agribusinesses (huge growth sector) with access to capital are already shifting their operations towards drought proof capability. The methods they are using to do this are feed lots, factory farms, aquaculture and hydroponics as well as building massive private water stores. All of these methods are capable of being made drought proof with sufficient food storage capacity, technology and energy. When water is scarce and food prices are high its worth the investment to be able to continue to supply the market. The worse droughts get the more the incentive to use these methods. The great tragedy is that as other industries are reducing their emissions due to climate change the agricultural industry is massively expanding its emissions because of climate change.

That is the problem that Fish Farmers wants to attack. We can make both aquaculture and hydroponics drought proof without all the waste water processing and recovery technology and obviously without all the energy to run all that gear. That is how we generate most of our greater than 70% electricity savings and pretty much all of our capital savings. That is our business case: the same productivity as an aquaculture and hydroponic operations with 30% less capital and a whole stack of operational cost savings. Fish and veg production at a lower cost of production that is also drought proof means reliability of supply and higher profits. It really is a no brainer. Good for the environment and good for our investors bank balances.

Ok I get that but still why grow trout then?

Trout are a carnivorous fish and at this stage they have to be fed a certain amount of fish meal from wild caught fish. Its probable that the CSIRO is going to be able to develop a non fish meal fish food for carnivorous fish just like they already have for prawns. However, its a common practice of unsustainable industries to ask to be allowed to continue as per normal while waiting for a future technological solution. I’ve never liked that in other industries (clean coal anyone) and I don’t want to do that myself. However, you have to be pragmatic and be the change you can be until you can be the change you should be.

Unfortunately the economic and regulatory factors mean that at this point in time its not possible for us to grow omnivorous or vegetarian fish** and the market isn’t too fond of them anyway. For example Carp is an excellent aquaculture species in terms of production but the market for carp is some what small to say the least. Even so we could still make a commercial aquaponics system work on carp and be very profitable if it were not illegal to farm carp. Especially with the extra legitimate environmental credentials that would give our plant products. Similarly other species like Tilapia, Basa and Paku are great candidates for future aquaponics operations but the market price for them is rather low and they are also illegal to farm in Australia.

There is nothing we can do about that now. So our strategy is to do what we can now, increase our market presence, clout and influence and work for profits to give us the capital to facilitate change over time. As the price of animal protein in general goes up and the price of fish in particular market forces will place pressure on our governments to allow the farming of vegetarian species. Putting the stand alone aquaculture and hydroponic industries out of business is a big enough goal for now.