Density and gender segregation effects in the culture of the caridean ornamental red cherry shrimp Neocaridina davidi Bouvier, 1904 (Caridea: Atyidae)

Abstract

The effect of density on growth, sex ratio, survival, and biochemical composition of the red cherry shrimp, Neocaridina davidi Bouvier, 1904, was studied to determine optimum rearing conditions in this ornamental species. It was tested whether gender segregation affected growth and survival of the species. To test the effect of density (Experiment 1), hatched juvenile shrimp were kept at three different densities: 2.5, 5, and 10 individuals l-1 (D 2.5 , D 5 and D 10 , respectively). To test the effect of gender segregation (Experiment 2), 30-day juveniles were reared in three conditions: culture with only females, culture with only males, and mixed culture (females: males 1:1) at 5 individuals l-1 density. Experiments lasted 90 days, and shrimp were weighted either every 30 days (Experiment 1) or 15 days (Experiment 2). At day 90, females kept at D 2.5 weighted 45% more than females stocked at D 10 (P < 0.05), whereas females from D 5 did not differ from those of other densities (P > 0.05). Males at D 2.5 weighted 29% more than D 5 and D 10 (P < 0.05). Survival was high and unaffected by treatment. Sexual differentiation did not differ among treatments. Females from D 2.5 had the lowest lipid and protein content, which would occur if they had a higher spawning. Males from D 2.5 had higher content of proteins, probably due to their larger size. Gender segregation had no effect over growth and survival; females grew up to a larger size than males both in monosex and mixed culture. It was shown that given to their non-aggressive behavior, N. davidi is tolerant to a highdensity condition, which makes it feasible as an ornamental species.

Assessment of potential trade‐off between maternal colouration and offspring quality in the ornamental “red cherry” shrimpNeocaridina davidi(Bouvier)

“…Offspring weight and length increment of N. davidi for the period 30-60 days was significantly different for either males or females offspring. It was previously reported for N. davidi an increment in females' growth rate in this period with respect to males, related to the differential growth at sexual maturity (Vazquez, Delevati Colpo, Sganga & López Greco, 2017), which could account for the differences observed in this study. Weight increment for the period 0-30 days was higher in second spawnings as compared to first ones.…”

First report of Scutariella japonica (Matjašič, 1990), a temnocephalid epibiont from South-East Asia, found on introduced ornamental freshwater shrimp in European waters

“…Among infected shrimp, females more likely presented damages in the cuticle, suggesting that the activity of S. japonica might be higher on them than on males, what is supported also by the presence of eggs only on females. This is most likely a result of more surface available to attach on females which grow bigger than males (Vazquez et al, 2017), what can also be observed in quantity of vorticellids, which was also lower in males. On the other hand, females are often characterised with body covered by more intense pigmentation (Tomas et al, 2019), which probably creates favourable shelter conditions for scutariellids hiding in host gill chambers.…”

Body coloration, carotenoid content, spermatophore quality and biochemical parameters by effect of temperature in the caridean shrimp Neocaridina davidi (Atyidae)

“…This small caridean species is native to Asian lakes and streams (Cai, 1996), where temperatures range from 6 to 8°C in winter and nearly 30ºC in summer (Klotz et al, 2013). Several studies have demonstrated how easily this species can be cultured and maintained under laboratory conditions, due to its natural hardness to starvation (Pantaleão et al., 2015) and high tolerance to a condition of conspecific density (Vazquez, Delevati Colpo, Sganga, & López Greco, 2017). Moreover, female reaches sexual maturity approximately 50 days after hatching at 28ºC (Tropea, Stumpf, & López Greco, 2015) and displays a short life cycle with direct development, producing several successive spawnings with the same offspring quality (Marciano, Tropea, & López Greco, 2018; Sganga, Tropea, Valdora, Statti, & López Greco, 2018; Tropea & López Greco, 2015).…”