The catfish Pseudopimelodus atricaudus is a recently redescribed species from the Magdalena-Cauca basin. This catfish is vital in food security and has qualities that can be used for aquaculture production systems. However, more information on its bioecology and role in aquatic ecosystems is needed. Colombia fish farming reflects an annual sustained increase in production volumes. Nevertheless, the activity is restricted to a small number of farmed species, of which a large part are introduced species that could affect natural environments. Therefore, diversification with native species is essential, but reliable reproduction, larviculture, fry, and fattening technologies are necessary to develop their fishculture. The study aimed to evaluate the effect of four different types of prey on the first feeding of P. atricaudus larvae.
The yolk larvae (n=1200) of P. atricaudus were randomly distributed in 12 aquaria of 5 L volume, at a density of 20 larvae/L, and fed for ten days with four types of prey: nauplii of Artemia (NA), wild zooplankton <400 µm (ZS<400 µm), wild zooplankton >400 µm (ZS>400 µm) and decapsulated Artemia cysts (CD), at a rate of 10 prey/mL. Each treatment was evaluated with triplicates. In the experimental units, water quality parameters were measured daily: temperature, dissolved oxygen, oxygen saturation, pH, total ammonium, nitrite, hardness and alkalinity. Excess food and feces were removed from the bottom daily, and 20% of the water was exchanged in each aquarium. At the end of the trial, zootechnical variables were evaluated: weight gain (WG), length gain (LG), survival (S), and stress resistance (SR). Also, the first feeding larvae were morphologically described.
The results suggest that P. atricaudus begins exogenous feeding at 48.0 hours post-fertilization, with a maximum mouth opening of 491.8±30.1µm (90°), total length (TL) of 5.5±0.2 mm and total weight (TW) of 1.5±0.2 mg. Among the treatments evaluated, the higher LG (1.4±0.1 mm) and WG (9.5±1.4 mg) were recorded in larvae fed with ZS>400 µm (p<0.05) (Table 1). Likewise, the higher survival was recorded in this treatment (91.2±0.7%), showing a significant difference with those fed NA (73.2±3.1%) and CD (47.0±2.4%). The stress resistance test due to severe hypoxia was not statistically different between treatments (p>0.05) (Table 2).
The results suggest that using ZS >400µm to manage the first feeding of P. atricaudus larvae guarantees good growth and survival rates.