Effects of different temperatures on the growth and survival of mud crab (Scylla paramamosain) larvae

Abstract

This study aimed to evaluate the effects of temperature on the growth and survival of mud crab (Scylla paramamosain) larvae in two stages including zoea-1 to megalopa (the first experiment) and megalopa to crablet-1 (the second experiment). Each experiment was conducted in a completely randomized design with four temperature levels (27, 30, 33, and 36℃) in triplicate. Stocking density of 200 ind./L for the first experiment and 4 ind./L for the second experiment. Fiberglass tanks of 500-L (containing 300-L and 250-L of 25‰ water for the first and second experiment, respectively) were used in the experiments. The results showed that S. paramamosain larvae at zoea-3 and zoea-4 died at 33℃ or above, while the highest survival rate of this stage was found at 27℃ (11.5%). The growth and larval stage index during the zoea to megalopa stage were significantly higher in 30℃ (p<0.05) compared to those in the 27℃ treatment. In the second experiment, the survival rates of crablet-1 were highest (72.9%) at 27℃ and lowest (34,7%) at 36℃. The growth rate of crablets at this stage increased with increased temperature. The highest carapace width and weight (3.41 mm and 0.030 g, respectively) were recorded at 36℃. The findings of this study suggested that mud crab larvae should be reared at the temperature range of 27-30℃ to maximize their production.

Effects of different feeds and stocking densities on growth and survival rates of mud crab (Scylla paramamosain) at the stage from megalopa to crablet-1

“…59 S. paramamosain had the highest survival rate of 72.9% when fed 100% Lansyshrimp feed (called Lansy pellet feed in the present study). 29 In addition, the metamorphosis duration in the megalopa-to-crablet-1 stage of S. paramamosain (10.03-11.70 days) (Figure 3 ) was within the ranges recorded in species of the Sylla genus in other studies. The megalopa mud crab stage often lasts 7-10 days before molting to the first crab stage.…”

“…52 The information mentioned above may explain the low growth performance of experimental crabs fed NRD pellet feed compared to Lansy pellet feed. Besides, it recommended that in the practice of nursing crustaceans in the megalopa stage, formulated particle feed could completely replace live prey, 29,32 as pellets offer many advan-Effects of different feeds and stocking densities on growth and survival rates of mud crab (Scylla paramamo… Israeli Journal of Aquaculture -Bamidgeh tages compared to natural or live feeds. In terms of nutrient content, artificial feed offers a nutritionally balanced diet with known nutrient content, such as total lipids and protein, that will promote growth and reproduction in the crustacean.…”

“…For the natural and live feeds, Artemia with live or frozen forms has often been practiced with the addition of prawn or shrimp meat, fish meat, and dried shrimp. Besides, Acetes shrimp, 25 dried mud worms, or artificial feed (larva-shrimp feed), 3,9,10,26 minced trash fish, green mussels, 15 brown mussels, 1 or artificial feed 10,[27][28][29] have also been used. Some previous studies have shown that the role of natural feed in the hatchery in the larval stages of mud crabs cannot be completely substituted for artificial feed, but the combination of them is still recommended.…”

“…30,31 Still, in the megalopa stage, formulated particle feed could completely replace live prey. 29,32 The development of pellet diets or aquafeed for aquaculture species has gained much interest nowadays, as pellets offer many advantages compared to natural feeds. In terms of nutrient content, artificial feed offers a nutritionally balanced diet with known nutrient content, such as total lipids and protein, that will promote growth and reproduction in the crustacean.…”

Efficacy of different wet feeds on the growth performance of mud crab Scylla serrata during fattening in cages

“…Each treatment had 10 replications, and there were 40 cages in total. As crab is a highly cannibalistic animal, they are usually cultured with a stocking density of one crab per cage (Begum et al 2009; Gabito and Baltar 2023). Growth parameters such as the initial weight of the mud crabs and length and width of the carapace were recorded prior to stocking.…”