We're not perfect, we have all been there and its an area that we need to be in touch with daily during the summer if you want to make the most of the growing season!
So a little bit about Dissolved Oxygen then...
Maintaining a healthy level of oxygen is key to keeping your fish feeding, so its important to regularly take oxygen readings, by doing so you will quickly learn the contributors to changes in DO2, making it easier for you to anticipate a problem so you can act before any disaster.
Cool water holds oxygen much more effectively than warmer water, so as water temperatures increase, the waters ability to hold DO2 is decreased. Coupled with the rise in oxygen demand from aquatic life within the water, theres no wonder summer oxygen levels fluctuate so much, which is why its so important to check oxygen regularly.
We always measure oxygen in mg/l rather than %saturation, this gives us a more comparable reading. What happens when oxygen is low?
- Above 4mg/l is healthy
- Below 3.5mg/l carp will reduce feeding
- Below 3mg/l carp will almost stop feeding completely
- Below 1.5mg/l you will begin notice fish gasping for air at the surface
So by the time you see physical signs of distress, the oxygen has probably been too low for a long time, this is why its important to know when oxygen is on its way down because feeding when oxygen is low will add to the problem as the feed isn't going to be eaten and the feed waste will contribute to the decline in dissolved oxygen.
Oxygen is transferred through surface diffusion on a lake (another reason why water surface area is more important than depth) but once the water is at 100% saturation, no more oxygen can diffuse through the surface. However weed and algae produce oxygen as they photosynthesise, which lifts the dissolved oxygen level above 100%, this is how water becomes supersaturated. Obviously as photosynthesis can only occur during daylight hours, this is the period when oxygen will be increasing dramatically, although the respiration process during the night will cause oxygen to decline during the hours of darkness. So your highest reading of dissolved oxygen will be at the end of the day when the lake has had a full day of sunlight, and your lowest reading will be at first light after the lake has been through a night of weed/algae respiration before the sunlight then allows photosynthesis to lift the oxygen level once again. Its a good idea to take a reading just before first light occasionally, so that you know what level of oxygen you have when it is at its lowest point to give you peace of mind because taking a reading after just 1-2hours of sunlight can be the difference of as much as 1mg/l.
This is another reason why weedy waters are not ideal for growing fish, because DO2 will be very high during the daylight hours and very low during the night, this inconsistency is not what you want when growing fish!
Bacterial action during the organic breakdown process of silt, weed, leaf-fall etc will also contribute to a depletion in oxygen. Which is why its a good idea to apply chalk during the winter to accelerate the breakdown of silt before the summer when the biological oxygen demand (BOD) of the water is much higher!
Warm stormy weather is classic oxygen zapping weather, we had a few stormy days in the middle of the summer in 2016 which caused lots of problems in fisheries all over, and even some of our ponds suffered. So its always a good idea to have aeration on standby, and cut back on the feeding if oxygen takes a dive!
Summer is obviously the time to be on the ball with the oxygen meter, especially post-spawning with the added oxygen demand from the growing fry! This is why we take stock management so seriously, removing offspring and unwanted fish gives the best chance to resident fish that you want to grow!
Oxygen monitoring equipment
There are a number of oxygen reading probes on the market, and we see plenty of variations, but there is only 1 that I could recommend. Cheap probes don't last and they often need constant calibration, whereas the probe that we use is turned on and accurately reading oxygen with the touch of a button, I've had the same oxygen meter for 5 years, without an problems or battery changes! Without a doubt its a must have tool for any fish farmer or fishery owner! Contact for more information or order yours from us now!
We have been working with Scientific Analysis Laboratories (SAL) to analyse our feeds for impact on water quality comparing them to conventional fishmeal feeds, and traditional angling baits which often raise concern for their contribution to ammonia pollution (i.e. Oily processed meats).
The aim of the trial was to test the ammonia contribution of different feeds commonly associated with over-feeding. The trial was carried out over 3 weeks, independently verified by SAL, and the results were immediately eye-opening, consistently showing the ammonia contribution of our feeds to be as much as 5 times lower than fishmeal feeds.
We knew that by avoiding the use of fishmeal or high oil levels in our feed formulation, our feeds must have a much lower environmental impact, so its pleasing to have the data to back up our theory.
We have set up a youtube channel where we will archive all the videos we make. You will find videos featuring feeding advice, harvest clips, fishery work etc. All videos and news are also posted on our facebook page to so make sure your following!
Lots of fisheries and clubs have a stock pond facility, but we see so many which aren't utilised to there full potential.
Often they will be far to small to support any weight of fish at all. The purpose of a stock pond is normally just to hold unwanted fish from a main lake, however a stock pond is a valuable asset to any fishery. Its an opportunity to produce your own fish which is the safest source of stock fish for your own waters.
So its worth making the most of your assets by creating a productive environment that your fishery/club can benefit from. Our recently developed stock ponds were created for fish production so they need to suit the requirements of growing carp, if your going to invest in feeding your fish then its important to create an environment which will allow you to take full advantage of the growing season so the fish can fully utilise their diet at key times.
The key ingredients to a productive growing pond are:
Exposing the water to light and air
One of the most common and underestimated feature of stock pond is tree cover. This is the easiest and most productive job a fishery manager or club can do to make a water 10 times more healthy and productive. A shaded pond can be as much as 3 or 4 degrees cooler than an exposed pond during the summer, bad news if you want to make the most of the growing season! By cutting down trees and strimming around the pond you are exposing the surface of the water to air flow which will maximise oxygen diffusion and minimise leaf fall and silt build up. Light and air restrictions over water will disrupt the whole ecology of the pond, preventing the bloom of healthy algae which play an important role in the natural food chain and convert organic waste into healthy forms of nitrate.
An exposed pond in the middle of an open field is far more productive than a sheltered pond surrounded by trees!
The depth of the pond is key to making the most of a growing season, the shallower the pond, the quicker it will warm up. Fish will feed more actively in warmer water and will convert food into bodyweight much more effectively.
A featureless lakebed is a key property of a growing pond in order to keep fish actively moving and burning energy, so they need to feed to replace that energy. This is also important for harvesting, draining and sterilising the pond.
Having a drainable water makes stock management so much easier, if you cant drain the pond then you cant catch 100% of the fish. A simple down pipe on a 90 degree elbow which can be tilted to drop the water level is as simple as it gets.
Marginal plants not only look nice but they will protect the margins of the pond preventing bankside erosion and slippage, they also play an important role in the nitrification cycle of the pond.
Any feature in a stock pond will have an effect on the performance of the fish, snags and deep areas provide a feature where, at certain times, fish will spend a lot of time, which is fine from a fish husbandry point of view, but from a productivity point of view this is not what we want. You want fish to be constantly on the move and burning energy making it difficult for parasites to complete a life cycle by transferring from fish to fish. It also makes it more difficult for predators if fish are constantly moving around the pond rather than localised around a feature.
Cormorants, mink and otter are becoming a more widespread problem. The stress predators cause on fish is just as damaging as the physical damage they cause. Its important to keep stock ponds a stress free environment to prevent fish from taking refuge from predators. It doesn't take long to set up lines across a stock pond to prevent cormorants from landing. Fencing out otters and mink is slightly more labour intensive but if your not protected from them then you're on borrowed time!
If you have a stock pond, they are a very useful tool if taken seriously and you can achieve brilliant growth rates if you create the right environment, which will provide you with a useful source of home-grown fish.
Ben has been to back to where he studied at Sparsholt College to introduce BP Milling to the students before feed trials commence!
Fishery management students at the leading fishery management college, Sparsholt, have been running feed trials with our new cereal blend “BP GOLD” to assess its performance as a grower diet.
The trial will run for 6 weeks in the indoor NATC (National Aquatics Training Centre) facility on Carp between 5 and 15grams. From this we will receive FCR’s (Feed Conversion Rates), the effectiveness of protein utilisation and the cost efficiency the ration.
Whilst our focus will remain on a cost effective food source for conditioning and growing stock in a fishery environment, it will be interesting to see how the ration performs in a controlled environment.
We look forward to working with Sparsholt in the future analysis and development of our formulations, watch this space!
Our pellets are formed through ‘cold pressing’, this ensures that all proteins are un-damaged through the unnecessary and expensive process of excessive heat conditioning prior to pelleting. Our pelleted feeds are formulated to break down fast (typically within 30 minutes) for efficient digestion, but we have products available to lengthen breakdown time if required.
We don't lose any sleep over feeding fast breakdown pellets to fish for a number of reasons:
1. The breakdown of our pellets keep fish grubbing around, lengthening feeding spells which helps to combat silt build-up and prevents weed beds from establishing.
2. As the pellets break down, some flakes of cereal begin to float, suspended in the middle of the water triggering a feeding frenzy that current clients will be familiar with.
3. Our pellets are formulated from home-grown cereals without any fishmeal or high oil levels, so any wastage is organic with minimal environmental impact on water quality
4. In our trials, the fish have normally cleared up the daily ration within a few minutes anyway!
Stocking big fish is always risky, but to stock them and call it "job done" is madness.
A fish of upper 20 or 30lb has had things its way for 8 years or more on a fish farm. Lots of space, food and usually a clean clay pond, so they're used to having their pellet ration presented cleanly infront of them daily.
For example a 30lb fish fed 3% bodyweight/day would be fed around half a kilo/day everyday. Thats 3.5kg a week to feed 1 fish.
So when stocked into a silty lake with the added stress of competition and anglers, and the daily feed ration no longer presented on a clean clay substrate, is there any wonder these fish struggle to hold there weight, and often turn belly up.
You are expecting a huge fish to find 3.5kg/week by digging through the silt to find "naturals" to sustain its bodyweight. And these beasts are capable of eating in excess of 5%/day!!
Thats why smaller fish tend to do better, because in a fish farm you can stock a large number of fish and still keep a healthy biomass in each pond. More fish, therefore more competition for food when fed, so when they're stocked out they are used to searching for grub aggressively.
If your going to stock big, give it to them their way. If you put an obese man out in the jungle, who's had it his way on benefits, would you expect him to thrive?
Ben Pinniger the founder of BP Milling won the Young Entrepreneur of the Year Award at the recent Enterprise Wiltshire Awards.
Ben was up against a very strong field but the Judges really liked his hard work ethic and the positive environmental improvements his fish feed provides.
“This is a fantastic achievement for us in our first 12 months of trading and hugely encouraging to have our hard work recognised” said Ben. “It is great to have such an endorsement from Enterprise Wiltshire and I look forward to making the business more successful this year”
In addition to the Award Ben also received a cash prize which he is looking to invest in new production plant to increase his manufacturing capacity. “The recently launched BP Milling website has increased our volume of business and I need to keep my customers happy by producing good quality fish feed so the award was very timely” stated Ben.
BP Milling have made it into the final 3 of the "Enterprising Wiltshire Awards" for the "Young Entrepreneur" category, up against some strong competition, the winner will be announced at the awards on the 20th of March!
We would like to take this opportunity to thank our clients who have supported us in our first year of supply, the feedback has been fantastic and the results are already beginning to show in many of our clients waters! We look forward developing a new product this year and further improving our feed service!