Species
Atlantic Salmon
(Salmo Salar)
The use of photoperiod in Atlantic salmon is implemented in freshwater to induce smoltification, a process specific to Salmo salar, in which the species develops anatomophysiological adaptations preparing it for entry into seawater (Björnsson et al., 2000). In seawater, artificial photoperiod serves two parallel objectives: on one hand, it aims to prevent premature maturation by inhibiting melatonin, a hormone secreted by the pineal gland that, under a certain threshold and frequency, stimulates gonadal development (Migaud et al., 2006). On the other hand, continuous light stimulates growth through improved feeding behavior and muscle fiber development (Johnston et al., 2003), allowing for larger fish and reduced production cycles.
Coho Salmon
(Oncorhynchus kisutch)
The strategy of artificial photoperiod in Coho Salmon aims to induce enlarge during the growth phase (Thorarensen et al., 1989). The most common strategy is to apply a constant light photoperiod in the months leading up to harvest to take advantage of androgenic stimulation provided by the natural increase in daylight hours.
Nile Tilapia
(Oreochromis niloticus L.)
Aware of the potential of this species as a source of animal protein for human consumption, the R&D Department of Bioled -along with producer partners in Central America- have focused on studying different photoperiod regimes to enhance the growth and feeding of tilapia on a commercial scale. Additionally, field testing of submersible luminaires that meet the high-temperature conditions characteristic of these types of cultivation is currently underway. The effect of photoperiod on Nile Tilapia growth has been demonstrated in various studies under experimental, RAS, or indoor conditions (Wang et al., 2020; López Betancourt et al., 2020; Cinense et al., 2018).
Whiteleg Shrimp
(Litopenaeus vannamei)
In crustaceans, light stimulates feeding behavior (Sanudin et al., 2014), growth, and molt rate (Guo et al., 2011; Flecknstein et al., 2019). The widely cultivated species Litopenaeus vannamei have specific receptors for certain wavelengths of light (Matsuda and Wilde, 2010), indicating they are more sensitive to certain light spectra when exposed to photoperiod. The main challenge of using photoperiod is to provide the quality and quantity of light conditions to find the best application of artificial photoperiod in current farming systems. In this regard, Bioled has conducted two commercial-scale studies where a high degree of attraction of L. vannamei to light sources in the 380 nm-690 nm spectrum, especially during natural darkness hours, has been observed. This implies new alternatives for the use of artificial photoperiod in the species, such as increasing the feeding rate during the night or using light as a mechanism to attract individuals during harvesting.
Pacific Bluefin Tuna
(Thunus orientalis)
It has been demonstrated that the use of photoperiod in Pacific bluefin tuna is capable of increasing larval growth and inducing recirculation (Chen et al., 2016), while also reducing mortality during transfer to sea (Ishibashi et al., 2009). It is also relevant to consider that providing a uniform photoperiod during the winter solstice stage is effective in accelerating sexual maturity and obtaining more resilient individuals for seeding in the sea (Higuchi et al., 2023). Continuous light regime is capable of increasing development and improving survival (Partridge et al., 2011). Multiple studies confirm that the latter significantly improves larval survival, which is the main bottleneck during RAS production (Kazunori et al., 2018; Tamura et al., 2017). In other words, the use of artificial photoperiod in this species is an alternative to explore for current production systems, both in RAS and at sea.
Rainbow Trout
(Oncorhynchus mykiss)
The use of artificial photoperiod in rainbow trout (Oncorhynchus mykiss) is employed similarly to Atlantic salmon, aiming to achieve objectives such as smoltification induction and subsequent improvement of productive performance by increasing growth rates and reducing farming times through constant light regimes (Taylor et al., 2006). It has been observed that artificial photoperiod increases certain molecular markers linked to growth (Morro et al., 2019). On the other hand, there are studies (Leonardi & Klempau, 2003; Valenzuela et al., 2006) linking the use of photoperiod with various immunomodulations caused by it.
