Nutritional quality of the hepatopancreas and gonads of orange portunid mud crab, Scylla olivacea was evaluated for each gender under four treatment of different water velocities (0, 20, 40 and 60 cm s −1 ), in terms of nutrient reserve and nutrient for reproduction. About 56 crabs were used in this study in which fatty acids composition was analysed using gas chromatography mass-spectrometry (GC-MS). For hepatopancreas analysis, monounsaturated fatty acids (MUFAs) were present in the highest fatty acids concentration, followed by polyunsaturated fatty acids (PUFAs) and, saturated fatty acids (SFAs). However, long-chain polyunsaturated fatty acids (LC-PUFAs) were displayed in low concentration in the hepatopancreas. Total fatty acid (TFAs) composition was significantly higher at moderate velocity of 20 cm s −1 compared to other water velocity treatments. For gonad analysis, 20 cm s −1 showed the highest TFA concentration of 93.34 mg g −1 while, the lowest concentration of 3.90 mg g −1 occurred at 0 cm s −1 . There were significant differences in male and female crab’s fatty acids contents of gonads at all flow velocities challenged ( p < 0.05). PUFAs and MUFAs were dominant while, SFAs were observed at low concentration. This study revealed that, concentration of PUFAs increased as gonad maturation increased. The decreasing concentration of hepatopancreas fatty acids over the culture period indicated that nutrient was shifted from the hepatopancreas, to be used as energy reserved to gonads for further growth of eggs and offspring. The linkages between water flow strength, hepatopancreas, and gonad fatty acids concentrations, is fundamental knowledge useful in establishing efficient habitat velocities selection which will improve aquaculture production of mud crabs with high quality broodstock.

The data collected in the present work correspond to the behavioral, Hepatosomatic Index (HSI), Gonadosomatic Index (GSI) and total lipid analysis between male and female mud crabs, Scylla olivacea at different water velocities. A total of 56 immature male and female crabs were used in this data article. The important criteria for estimating the selective habitat facing by S. olivacea is a considerate of (1) the behavioral range in response to abiotic factors (and how it adapt ontogenetically) and (2) the movement of the crab under wild velocities situations. This work purposes to recognize the performance, locomotion rate and escaping capability of S. olivacea under stagnant and flowing water situations and to discuss the significance of horizontal walking to habitat choice. The collective outcomes clearly show that the locomotor activities and escaping capabilities of S. olivacea were influenced by water flow in the mangrove habitats. For the HSI data, velocities of 20 cm/s were the highest increased mean HSI percentage and highest mean HSI percentage in males and females was recorded on the end of the experiment. For GSI percentage of male and female crabs, 20 cm/s dominates the highest increases mean GSI, followed by 60, 40 and 0 cm/s. For total lipid percentage, the results showed that, the mean total lipid of hepatopancrease, muscle and gonad were increased at the beginning and decreased at the final in each water velocities except for 20 cm/s over a culture period of 60 days. Velocities of 20 cm/s were the highest increased mean total lipid percentage followed by 40, 60, and lastly 0 cm/s. The high flow velocities inhibit the production of hepatopancrease and gonad, in terms of nutrients from food used to endeavor the stress condition faced.

This study was designed to determine the locomotor, escaping capability and fatty acids (FAs) composition of muscle Scylla olivacea mud crabs at different water velocities. Male and female immature S. olivacea were cultured at 0, 20, 40 and 60 cm/sin a recirculating marine aquaculture system. Increase in flow velocity increased the mean locomotor activity and escaping capability of the crabs. Significant differences were observed between sexes for both activities in all velocities tested (p < 0.05). Male and female crabs reared at the lowest flow velocity (0 cm/s) exhibited a mean of 13 and 55 locomotion per 15 minutes tested, respectively. Meanwhile, in the highest flow velocity (60 cm/s), male and female crabs exhibited 61 and 70 locomotion’s per 15 minutes. A total of 3111 locomotion were recorded during the entire experiment. An increase in the water velocities increased the mean escaping capability of the crabs. A total of 32 crabs attempted to escape during the flow velocity tests (0 cm/s; n = 3, 20 cm/s; n = 9, 40 cm/s; n = 11, and 60 cm/s; n = 9). The locomotor of crabs increased gradually and peaked at 40 cm/s (seeking for shelter). By contrast ≥ 40 cm/s the locomotor of crab decreased (defensive mode). For FAs analysis, total fatty acids (TFAs) content was found highest at 20 cm/s compared to other velocities. This study clearly show that the locomotor activities, escaping capabilities and FAs composition of S. olivacea were affected by water velocities under laboratory conditions.

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