Sea cucumbers belonging to echinoderm are traditionally used as tonic food in China and other Asian countries. They produce abundant biologically active triterpene glycosides. More than 300 triterpene glycosides have been isolated and characterized from various species of sea cucumbers, which are classified as holostane and nonholostane depending on the presence or absence of a specific structural unit γ(18,20)-lactone in the aglycone. Triterpene glycosides contain a carbohydrate chain up to six monosaccharide units mainly consisting of d-xylose, 3-O-methy-d-xylose, d-glucose, 3-O-methyl-d-glucose, and d-quinovose. Cytotoxicity is the common biological property of triterpene glycosides isolated from sea cucumbers. Besides cytotoxicity, triterpene glycosides also exhibit antifungal, antiviral and hemolytic activities. This review updates and summarizes our understanding on diverse chemical structures of triterpene glycosides from various species of sea cucumbers and their important biological activities. Mechanisms of action and structural–activity relationships (SARs) of sea cucumber glycosides are also discussed briefly.

Salmacis sphaeroides(Linnaeus, 1758) is one of the regular echinoids, occuring in the warm Indo-West Pacific, including Johor Straits, between Malaysia and Singapore. In order to investigate the developmental basis of morphological changes in embryos and larvae, we documented the ontogeny ofS. sphaeroidesin laboratory condition. Gametes were obtained from adult individuals by 0.5 M KCl injection into the coelomic cavity. Fertilization rate at limited sperm concentration (10−5dilution) was96.6±1.4% and the resulting embryos were reared at 24°C. First cleavage (2-cell), 4-cell, 8-cell, 16-cell, 32-cell, and multicell (Morulla) stages were achieved 01.12, 02.03, 02.28, 02.51, 03.12, and 03.32 h postfertilization. Ciliated blastulae with a mean length of174.72±4.43 μm hatched 08.45 h after sperm entry. The gastrulae formed 16.15 h postfertilization and the archenteron elongated constantly while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larva started to feed unicellular algae in 2 d, grew continuously, and finally attained metamorphic competence in 35 d after fertilization. Metamorphosis took approximately 1 h 30 min from attachment to the complete resorption of larval tissues and the development of complete juvenile structure with adult spines, extended tubefeet and well-developed pedicellaria, the whole event of which usually took place within 1 d postsettlement. This study represents the first successful investigation on embryonic, larval, and early juvenile development ofS. sphaeroides. The findings would greatly be helpful towards the understanding of ontogeny and life-history strategies, which will facilitate us to develop the breeding, seed production, and culture techniques of sea urchins in captive condition.

The present study is an attempt to describe the size frequency distribution, length weight relationships and fecundity estimates of long-spined Sea Urchin, Diadema setosum from the Pulau Pangkor, Peninsular Malaysia. In total 101 specimens of D. setosum were collected from the inter-tidal reef of Pulau Pangkor of Parek during the breeding season in May–August, 2010. Individual total length (TL) was measured using digital slide calipers and individual body weight (BW) was taken using a digital balance. Mean length of D. setosum was estimated as 59.66 mm and the mean weight was 101.68 g. Among the 101 specimens, 52 were males and 49 were females, indicating a sex ratio of male to female of 1:0.94. The logarithmic form of length-weight relationship of D. setosum was Log W = −1.3977 + 1.9049*Log TL, while the exponential form of equation obtained for the length-weight relation was W = 0.04*TL^1.9049. The value of regression co-efficient (r²) estimated for the species was 0.63. The mean fecundity was estimated at 7,313,600 (±567,992) with a range between 6,290,000 and 7,980,000 eggs. Analysis of the relationship between the absolute fecundity (F) and total length (TL), and also between the fecundity and drained body weight (DW), revealed a linear regression model with a positive and significant relationship. This study presents results on the total length-body weight relationships and fecundity estimates of this Sea Urchin from Pulau Pangkor, Peninsular Malaysia for the first time.

Production trials of threatened snakehead fish (Channa striatus) were carried out under different stocking densities in earthen ponds of Bangladesh. The average weight and length of the fingerlings during stocking was 17.63 ± 1.23 g and 13.21 ± 0.52 cm. Fingerlings were stocked at 5000 ha⁻¹ in treatment-1 (T₁), 6250 ha⁻¹ in treatment-2 (T₂) and 7500 ha⁻¹ in treatment-3 (T₃) respectively. Fish in all the experimental ponds were fed with supplementary feed comprising of fish meal (30%) and mustard oilcake (70%) at the rate of 3–6% of estimated body weight two times per day. In addition, trash fish were supplied at the rate of 2–3% of the estimated biomass on each alternate day. In situ water quality parameters of the pond were within the suitable range for fish culture. The growth and survival of fingerlings were significantly higher in T₁ than in T₂ and T₃. The food conversion ratio was significantly lower (P<0.05) in T₁ than in T₂ and T₃. The estimated gross and net production of fish was higher in T₁, followed by T₂ and T₃. Overall, the highest growth, survival and production were obtained from T₁. Therefore, it could be concluded that of 5000 fingerlings ha⁻¹ is the most suitable stocking density for culturing C. striatus under a monoculture system in the earthen ponds for better production.

The fingerling-rearing experiment of the threatened catfish, Mystus cavasius was carried out at different stocking densities in earthen nursery ponds. Twelve-day-old fry were stocked at 200 000 ha⁻¹ in treatment-1 (T₁), 250 000 ha⁻¹ in treatment-2 (T₂) and 300 000 ha⁻¹ in treatment-3 (T₃) respectively. The mean length and weight of fry at stocking was 1.24 ± 0.25 cm and 0.11 ± 0.04 g respectively. Fry in all the experimental ponds were supplemented with SABINCO nursery feed for the first 14 days and starter-I feed for days 15–56. The physico-chemical parameters and plankton population of pond water were within the suitable level for fish culture. Growth in terms of final weight, final length, weight gain, length gain and specific growth rate and survival of fingerlings were significantly higher in T₁ than those in T₂ and T₃. Feed conversion rate was significantly lower in T₁ followed by T₂ and T₃ in that order. Significantly higher number of fingerlings was produced in T₃ than that in T₂ and T₁. Even then, consistently higher net benefits were obtained from T₁ than those from T₃ and T₂. Among the treatments evaluated, 200 000 fry ha⁻¹ was the best stocking density considering the highest growth, production and net benefits of fingerlings of M. cavasius in nursery ponds.

The present study investigates the geo-morphological features, hydro-biological profiles and resource characteristics of some selected wetlands in Brahmanbaria district, Bangladesh. Two categories of wetland have been classified on the basis of area such as the small category (40–100 ha), which belongs to 11 wetlands and the large category (100–200 ha) to nine wetlands. The mean depth of all the surveyed wetland does not exceed 3.29 ± 0.83 m. The mean value of organic matter was measured as 7.5 ± 6.34%. The maximum organic matter was recorded at Gagotia beel (24.60%) and the minimum organic matter was recorded at Kajolia beel (2.06%). The mean value of organic carbon was measured as 3.93 ± 3.33%. The highest amount of organic carbon was found at Gagotia beel (12.95%) while the lowest amount of organic carbon was observed at kajolia beel (1.08%). Soil texture indicates the percentage composition of sand, silt and clay in sediment. The average concentration of sand, silt and clay was recorded to be 53.31 ± 15.32, 17.61 ± 9.56 and 29.08 ± 12.87%, respectively. Among the 20 selected wetlands examined, 13 were found to be perennial wetlands where water is available throughout the year. There was significant difference among different wetlands in terms of organic carbon, organic matter, sand, silt and clay (P < 0.05) as analyzed by One Way Analysis of Variance (SPSS v.22). The sampling stations were presented as a map created by GIS (ArcMap v.10.1). This qualitative and quantitative assessment will not only provide new information about the geo-morphological and hydro-biological insights into the wetland but also will facilitate the development, management, and conservation of aquatic biodiversity in a significant and worthwhile manner.