Worldwide, light emitting diode (LED) lighting technology is being whole-heartedly embraced by agricultural enterprises because of the sustainability inherent in its use. Energy costs are 60% less than that of other lighting systems. But additionally, and perhaps more importantly, LED lighting systems can be an incredibly powerful production tool in indoor aquaculture facilities, if designed and managed properly.
At Aquaculture America 2015, the management staff at a commercial freshwater recirculation facility growing barramundi reported a significant reduction in their feed conversion ratios (1.4 to 1.06) after replacing the traditional lighting in their grow-out area with a programmable, dimmable, custom-LED lighting system.
Animals respond to light. It is one of the essential elements for life on earth. Each species’ response to light has evolved over thousands of years and has developed so the animal can not only function but also prosper in its natural environment. Most importantly, in nature, light patterns, not temperature, are the most constant of environmental parameters throughout an animal’s lifetime.
Until now, the artificial lighting used in indoor aquaculture operations has not been representative of lighting in nature. This is mainly because of the limitations of traditional lighting sources. Environmental light has three characteristics: intensity, which is the quantity of illumination; wavelength, which is the colour or spectral output; and photoperiod, which is the duration of the light. Traditional lighting sources such as incandescent, fluorescent, and high-pressure sodium (HPS) lights can deliver photoperiod but are mostly fixed in respect to their intensity and colour, and therefore severely limited in creating a lighting system truly representative of light in nature.
In nature, light intensity gradually increases during the day and slowly decreases toward sunset. The quality of the light also changes during the day so that sunrise has a lot of red, high noon has a lot of blue, gradually changing back towards red by sunset. Additionally, the quantity and color of light an animal experiences in nature are governed by its geographical location. The intensity and colour of light at high noon in June is not the same for Bergen, Norway as it is for Seattle, Washington or Puerto Montt, Chile. Still more to consider, is that the quantity and quality of light an animal perceives in nature is also dependent on the seasonal changes in the earth’s orientation to the sun. So even at the same geographical location, the color and intensity of the light an animal receives is quite different between days in July and December.
Natural light changes continuously but traditional artificial light sources, because of the limitations of the technology, are unable to adequately simulate this change and therefore do not provide optimum rearing conditions for animals under culture.
The magic of LEDs
Enter Light Emitting Diode (LED) lighting technology. This new source of lighting has undergone major advances in development over the past 10 years. Because the method of light generation differs from traditional lighting sources, LED lighting can provide variable light intensity and wavelength, along with variable photoperiod, in a single lighting system.
This has opened up a whole new frontier in science for aquaculturists. For years, so many of us have been aware that traditional lighting systems were severely limited and in some cases counter productive to the aims of enhancing animal performance. Case in point, most of us have wondered about the “startle response” – a well known physiological and behavioral phenomena that occurs when the lights are suddenly turned on in the morning and how this negatively affects the animal’s first feeding of the day – the lessening of optimum feed intake and metabolism because of physiological stress. Yet, there has been, up to this point, no easily available lighting technology to create more comfortable, more enriching, and more natural light environments in indoor aquaculture.
LED Lighting systems can now do this but they must be properly designed and applied with expertise. Similar to traditional light sources, single LED lamps do not simulate natural light conditions. It is the lighting “system” that does this.
What do you want in an LED lighting system?
An optimum lighting system is designed to deliver a uniformity of light. Variability in light treatment delivery – with some tanks receiving one mixture of wavelength and light intensity, and others receiving a different mixture – will work against the aquaculturist’s goal of narrow grades of harvested animals with consistency in presentation. We all realize there are differences in the performance of fish in different tanks, but how many times do we acknowledge that this difference could be the difference in the lighting treatment (intensity and spectrum).
Secondly, a lighting system must be designed with the animals’ needs first, and those for human activity second. Unfortunately, it is all too common to see lighting systems in indoor facilities that have these priorities reversed: the lighting system having been designed to support husbandry activities rather than the needs of the animal under culture. With a properly designed LED lighting system the needs of both groups can be optimized.
An indoor aquaculture lighting system must be robust. It must be able to withstand the high humidity conditions often found in aquaculture environments. Yet, at the same time it should have broad flexibility, being able to accommodate the specific lighting needs at the different life stages (and even species of fish) as they move through the facility.
— Julie Delabbio
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Programmable LED lighting systems can even reproduce the colours and intensity of light observed at sunrise and sunset.
The ONCE Master Control programs up to 500 days divided into 20 lighting periods and up to 12 cycles, allowing for changes in light intensity and colour simulating sunrise and sunset, etc. Twin channels permit different lighting treatments in different parts of a facility.
Typical LED application illuminating grow-out tanks