Natural food intake by juvenileArapaima gigasduring the grow-out phase in earthen ponds

Abstract

In carnivorous fish species, zooplankton is one of the main food items in the early life stages and some fish species continue feeding on such food items further along the life stages even in the farming environment. In this study, the intake of natural food items was assessed in juvenile pirarucu Arapaima gigas reared in earthen ponds. Juvenile pirarucu (12.2 ± 4.32 g and 12.1 ± 1.13 cm) were stocked in fertilized earthen ponds (240 m²). For the analysis of the fish stomach content and plankton in the pond water, the fish and pond water were sampled weekly for 75 days and biweekly until the fish reached a mean weight of 750 g. Although artificial feed was used, pirarucu also ingested the natural food available in the pond water. Among the zooplankton, pirarucu demonstrated feeding preference for cladocerans despite the abundance of rotifers and copepods. Cladocerans were present in more than 80% of the stomach contents of fish up to 300 g and in 65%, 45% and 17% of fish of 301–500 g, 501–700 g and 701–900 g respectively. Copepods were present only in fish up to 500 g at low abundance. High ingestion of insects and plant material was observed in the stomach content of fish of all size classes. The results demonstrate that juvenile pirarucu ingest natural food available in the farming pond and suggests that the adoption of pond fertilization practices may have positive effects on fish growth performance.

Slightly salinized water enhances the growth and survival of Arapaima gigas larvae

“…It tolerates high stocking density, being resistant to handling, presents rapid growth of 10–12 kg in the first year of breeding (Brandão, Gomes, & Chagas, ; Rebaza, Rebaza, & Deza, ; Tavares‐Dias, Araújo, Gomes, & Andrade, ). In 2016, approximately 8 million tons of this species were produced in Brazil (IBGE, ), which has been increasing in the last few years in this country (Lima, Tavares‐Filho, & Moro, ). However, it is necessary to increase early A. gigas supply to meet the growing demand and to decrease the price of juveniles for its grow‐out phase (Nuñez et al, ).…”

Feeding frequency affects feed intake and growth in juvenile pirarucu (Arapaima gigas)

“…However, field validation of these results is needed, as agonistic behavior may be enhanced in intensive farming conditions (Costa-Bomfim et al 2014). Additionally, pirarucu of up to 900 g can feed on natural food available in the rearing pond, even when fed commercial feeds (Lima et al 2018), so that feeding frequency may be affected at this initial stage (Biswas et al 2006), further supporting the need for field validation.…”

“…10 g weight until they reach 500-1,000 g, and are transferred to the second stage until they reach 10-12 kg, which is the market size of farmed pirarucu (Lima et al 2015). Daily feed intake and feeding behavior have been studied with fish in the first stage Mattos et al 2016;Mattos et al 2017;Lima et al 2018). However, feeding frequency has been studied only for juvenile pirarucu of 1.0 to 1.7 kg (Gandra et al 2007), and no information is available on the feeding frequency of smaller fish.…”

Frozen zooplankton is efficient as natural food during pirarucuArapaima gigasweaning

“…Characteristic that reinforces the need to adapt the pirarucu not only to an inert food, with different texture and composition in relation to the natural food, but also to the behaviour of searching for food on the water surface. This is because the species, in the initial stages, feeds on zooplankton (Lima et al, 2018) and this is available in the water column, it is not a natural behaviour of the species to surface on the surface to apprehend the food. At the end of the training, the pirarucus were already conditioned to go to the surface to food search, and all animals were able to feed the commercial feed, similar to what was observed by Cavero et al (2003) when they performed the pirarucu feed training using artemia and zooplankton as the initial live food.…”