Dataset on reproductive status of ovary mud crab at different salinity levels

This article investigated how crabs responded to different culture salinities through ovarian maturation stages using combination of external morphology (ovarian coloration and gonadosomatic index), and histological assessment (oocyte structures and diameter sizes). A total of sixty immature crabs were sampled from coastal water of Setiu Wetlands, Kuala Nerus, Terengganu, Peninsular Malaysia, and were introduced to limb autotomy technique in order to induce molt. Crabs were reared until successfully molted, and leaves prior to hardened shell, before proceed with salinities acclimatization prior to salinity treatments (10, 20 and 30 ppt). Five crabs were randomly selected every 15 days throughout 60-day of culture (Day 15, 30, 45 and 60) for the assessment. The different between each ovarian maturation stages was recorded based on the color appearances, and Kruskal-Wallis analysis were done between gonadosomatic index and oocyte diameter sizes with different salinity treatments. Part of the data is associated with the recent articles [1], [2] and provided here as raw data of Supplementary materials.

Histological Characteristics on the Testes of Mud Spiny Lobster, Panulirus polyphagus (Herbst, 1793)

BACKGROUND AND OBJECTIVE

Mud spiny lobsters, Panulirus polyphagus (P. polyphagus) are one of the most important fisheries resources now-a-days due to quality that it's possessed. However, there is still lack of in-depth study about this species mainly on males testicular characteristics and sexual maturity size. Therefore, the present study was carried out to investigate the histological characteristics on the testes and sexual maturity sizes of mud spiny lobster, Panulirus polyphagus.

MATERIALS AND METHODS

The testes were dissected out and fixed in 10% buffered formalin solution for 11 h, dehydrated in 70% alcohol and lastly placed in tissue processor for 18±1 h at 60°C. The tissues blocks were cut at the thickness of 4 μm on a rotary microtome. Stained tissues were taken under Advance Microscope (Nikon Eclipse 80i Nomarski DIC). Collected data were analyzed using Microsoft Excel 2013. Data were presented as mean±standard deviation. Statistical analyses were done using one-way ANOVA using SPSS (Version 22).

RESULTS

These lobules of mature P. polyphagus were formed via different germinative lineage cells such as spermatogonia, spermatocytes, spermatids and spermatozoa. The histological characteristics of testes showed that the process of spermatogenesis went through the stages of four testes maturation which were spermatogonia I and II, spermatocytes I and II, spermatids and spermatozoa stages within different body weight of P. polyphagus. It was found that there were significant difference between body weight and carapace length to the testicular maturation stages (one-way ANOVA and p = 0.000).

CONCLUSION

The results of this experiment indicated that males P. polyphagus have four stages of testes maturation and can be considered to have fully mature testes that ready for fertilization at 452 g body weight (BW) and 107 mm carapace length (CL) or more.

Effect of Water Salinity on the External Morphology of Ovarian Maturation Stages of Orange Mud Crab, Scylla olivacea (Herbst, 1796) in Captivity

BACKGROUND AND OBJECTIVE

Mud crab from the genus Scylla are considered as one of the most demanded seafood items nowadays as their flesh has high quality, tasty and higher growth rate thus support and boosted expansion in aquaculture sector especially in Malaysia. Present study was designed to focus on the effect of water salinity on the ovarian maturation of orange mud crab, Scylla olivacea based on morphological characteristics.

METHODOLOGY

Samples were collected from Setiu wetlands, Terengganu, Malaysia from July-September, 2015. Ovarian maturation of S. olivacea was classified into four stages based on previous study which were: Immature (Stage 1), early mature (Stage 2), late mature (Stage 3) and fully mature (Stage 4).

RESULTS

Morphologically as the ovary develop the colouration start to change from translucent or whitish in colour and sometimes creamy to pale yellow, follow by light orange and lastly reddish orange. Stage 1 ovary was translucent and whitish in colour, stage 2 ovary was pale yellow in colour, stage 3 was light orange and stage 4 ovary was reddish orange in colour. Gonad Somatic Index (GSI) of S. olivacea remained low at stage 1 and 2 and began to increase started at stage 3. This present study involved three different salinities treatments, which treatment 1 (10 ppt), treatment 2 (20 ppt) and treatment 3 (30 ppt). Treatment 2 produce the highest number of stage 4 ovarian maturation based on colouration and the highest GSI recorded, follow by treatment 1 and lastly treatment 3.

CONCLUSION

This present study proved that salinity does affected the ovarian maturation of S. olivacea in captivity and provides important information regarding the effect of water salinity on ovarian maturation for further studies on reproductive biology of this species.

Sperm Viability Assessment over elapsing time maintained at 2 degrees C of orange mud crab, Scylla olivacea (Herbst, 1796)

The aim of this study was to evaluate how long the fresh sperm maintained at 2 degrees C would be utilized for fishery management. The study was conducted every 2 h to assess the sperm viability of orange mud crab Scylla olivacea. Evaluations were conducted as 3 treatments; T1, T2 and T3. In T1, the live specimens were sacrificed; for T2, only spermatophores were extracted and for T3 spermatophore extraction followed by homogenization to create a sperm suspension. All samples were stored with ice in an insulated box was keep fresh longer at 2 degrees C. The time '0' referred the immediate collection of sperm after the specimen was sacrificed. Spermatophore viability was determined using the sperm suspension by eosin-nigrosin staining method. Sperm viability for the fresh sample at time zero was 97.36 ± 0.53%. Viability of the sperm significantly decreased in the 2nd h in all treatments, T1 was 44.66 ± 0.54 to 4.2 ± 0.22% at 16 and 18th h, T2 was 36.56 ± 0.5 to 2.69 ± 0.06% at the 12 and 14th h and T3 was 33.69 ± 1.26 to 6.4 ± 0.29% at 8 and 10th h. In comparison, T1 showed significantly higher than other treatments (p < 0.05). Extremely low viability percentages were recorded in T3. This study also proved that the time elapse had significant impact on the percentage of viable sperm count.