The effect of density of Macrobrachium rosenbergii raised in earthen ponds on their population structure and weight distribution

Effect of Intensification on Grow Out of the Amazon River Prawn, Macrobrachium amazonicum

“…Decreasing mean harvest weight of prawns as stocking density increased was reported previously in several studies conducted with M. rosenbergii (D’Abramo et al 1989; Valenti et al 1993; Sampaio and Valenti 1996; Tidwell et al 1999). The same was observed with the average weight of each morphotype (Cohen et al 1981; Karplus et al 1986; D’Abramo et al 1989; Siddiqui et al 1997). The results of the present study shows that the density effect is markedly stronger when the variation occurs at lower levels in M. amazonicum ; the same occurs in M. rosenbergii (Valenti et al 1993).…”

On the safety of RNAi usage in aquaculture: The case of all-male prawn stocks generated through manipulation of the insulin-like androgenic gland hormone

“…OC males are less territorial than are the dominant BC males and hence, in many cases, are the most desirable for growers (Karplus et al, 1986). In accordance with previous studies Nair et al, 2006;Sagi et al, 1986), regarding marketable yields, the all-male population in the present study proved to be superior with an increase of about 17% in yields compared to mixed-sex population.…”

“…In M. rosenbergii, however, such mapping is not yet available, as the sex chromosomes are not morphologically distinguishable (Justo et al, 1991) and further research is needed to test this hypothesis. Moreover, the different growth rates could be attributed to the different ponds in which other environmental variables, including density, could have played a major role (Cohen and Ra'anan, 1983;Karplus et al, 1986;Sandifer and Smith, 1975). Furthermore, in the mixed-sex population,~50% of the total population grown in the pond were males, which could contribute to the lower growth rate of the normal females (Sagi et al, 1986).…”

Sediment-rejection mechanisms of 42 species of Australian scleractinian corals

“…The previous reports that crowding reduces growth rate and survival in prawns (Sandifer and Smith 1975;Smith et al 1981;Cohen and Ra'anan 1983;Karplus et al 1986) can be explained by these observations. Even with excess food available, prawn behaviour is modified by high density, so more time is spent in nonfeeding activities and less in feeding.…”

“…Crowding has been shown to reduce growth and survival in several prawn species (Sandifer and Smith 1975;Smith et al 1981; Cohen and Ra'anan 1983;Karplus et al 1986). The present paper looks at behavioural responses to crowding in Penaeus latisulcatus and examines how the distribution of food in an enclosure may modify that behaviour.…”