Installation, operation and evaluation of a submerged cage at 45M depth in crete for the rearing of red porgyPagrus pagrus

Abstract

Socio‐economic factors related to management of costal zones and biological parameters related to species‐specific requirements set limitations for the rearing location of net‐pen sea cages. A cage was designed and installed at 45 m depth based on the REFA Tension Length Cage technology at the cage facility of the Hellenic Centre for Marine Research in Crete. The cage‐net module consisted of a net‐pen contained within a hexagonal rigid frame to maintain the shape of the net. Vertical beams of the frame glider on six tension legs were placed in a circle. The operation of the cage was evaluated using a group of red porgy (Pagrus pagrus) for a rearing period of 4 months whereas a second group reared in a surface net‐pen cage served as control. Growth performance was similar between the experimental groups. The rearing method significantly affected fish skin pigmentation. Individuals reared in the submerged cage had a brighter skin colour and lower skin melatonin content compared with the ones reared in the surface cage. The presented submerged cage may provide a feasible alternative for rearing fish in exposed areas and particularly species requiring specific biological conditions, such as narrow temperature ranges and low light intensity.

Effect of feeding delay after self-feeder activation on growth performance and feeding behaviour of red porgy (Pagrus pagrus L. 1758): application to submergible cages with surface hopper

“…During the last decade, research associated with the optimization of red porgy's culture has improved, especially in matters that concern its reproductive biology (Kokokiris, Brusle, Kentouri & Fostier 1999; Mylonas, Papadaki & Divanach 2003; Mylonas, Papadaki, Pavlidis & Divanach 2004), larval rearing (Kolios et al 1997; Hernandez‐Cruz et al 1999; Mihelakakis et al 2001; Papandroulakis et al 2004) and growth (Rueda et al 1998; Maragoudaki et al 1999, 2001). However, research associated with the development of the technology for rearing in submergible cages is still at a preliminary stage (Papandroulakis et al 2008), although it is of considerable commercial importance for the aquaculture industry. The development of this technology will contribute not only to the solution of red porgy's discolouration problem, but also to the introduction of many demersal species, that demand considerate depths, in aquaculture (e.g.…”

“…Wild pre‐adult and adult red porgies can be found at depths between 50 and 150 m (Vassilopoulou and Papaconstantinou 1992), where conditions of temperature, intensity and spectrum of light differ from those of typical surface aquaculture. Trials of red porgy's culture in deep submergible cages seem to give satisfactory results concerning colouration (Papandroulakis, Anastasiadis, Lisac, Asderis, Bakolias, Divanach & Pavlidis 2008) and could potentially become the breakthrough needed for the successful cultivation of the species.…”

Suitability of artisanal fishery discards as feed for juvenile tub gurnard (Chelidonichthys lucerna L.) reared in sea bottom cages in the mid Adriatic Sea

“…The development of bottom cage technology may help resolve the current issues that exist with rearing tub gurnard and other benthic marine species that would be considered potentially interesting to aquaculture. For instance, bottom cages reduce the discoloration of red porgy (Pagrus pagrus L.) due to low light penetration (Papandroulakis et al, 2013). Bottom cages produce satisfactory growth rates for lobster (Homarus gammarus) (James, 2007).…”

Natural‐like pigmentation in cultured fish stocks, not only a matter of nutrition. A review of Salmonidae and Sparidae families, with a particular focus on the red porgy Pagrus pagrus

“…However, important physical factors such the water temperature (17°C-19°C), background bright colour, light intensity and blue light spectrum play important role in skin colour of this species (Pavlidis et al, 2008). This method achieves lighter skin and by affecting the concentration of melanin in melanosomes and the mobility of melanophores (Papandroulakis et al, 2013). Another alternative method for natural P. pagrus light pink without dark shadows pigmentation is achieved with rearing fish in sea cages with canopy, which protects the fish from sunlight (Figure 3).…”