International Journal of Aquatic Biology
Volume:9 Issue: 4, Aug 2020

Characteristics of the Lecane (Rotifera) community in psammon in Central Coast Vietnam were investigated. A total of 50 taxa were identified in samples collected at hygropsammon zones of temporary pools, contributing 4 new species to rotifers’ record of Vietnam. Psammonxenic species accounted for the largest percentage of Lecane community with 82%, followed by psammophiles (12%) and psammonbionts (6%). Influences of some environmental factors on the distribution of psammic lecanids were also observed. This group of organisms showed a slight tendency towards sand with grain sizes larger than 125 µm. Besides, other abiotic factors including pH, total phosphorus (TP) and total dissolved solids (TDS) were also found to significantly related to the distribution of some common Lecane species.

Blood biochemical parameters are important factors that can show the changes in health offering critical feedback on physiological condition of fish. In the present study, we examined a comparative study on the blood biochemical parameters in mature male and female goldfish, Carassius auratus. Plasma samples of 72 male and female goldfish that have been kept at 24°C for 30 days were analyzed and their biochemical parameters levels were determined. There were significant differences in all measured parameters between genders so that, maximum concentrations of the glucose (73.45±0.68 mg/dl) and calcium (8.32±0.05 mg/dl) were found in female fish, while the highest levels of the total protein (3.14±0.01 g/dl), cholesterol (281.65±3.19 mg/dl) and triglyceride (428.31±1.17 mg/dl) were measured in males. Based on the results, the plasma biochemical parameters changes vary considerably between male and female goldfish.

This study determined the influence of the lunar cycle, tidal fluctuation, as well as water physicochemical factors on the gonadal maturation of green mussel, Perna viridis, in Malampaya Sound, Taytay, Palawan, Philippines. Monitoring and sampling were conducted for the 6 months, from October 2017 to March 2018. It was observed that the lunar cycle has a direct influence on gonadal maturity. Gonadal changes in both male and female P. viridis were observed histologically and both exhibit the characteristic of lunar-synchronous pattern. It was observed that a high number of green mussels with spawning stages usually occur during the full moon and new moon. Furthermore, gonadal maturity was also affected by the tidal fluctuation. A higher number of P. viridis with spawning stages were recorded during spring tide, whereas the percentage of spent individuals were higher during neap tides. Furthermore, it was observed in the present study that salinity fluctuation could influence spawning of green mussel, wherein the number of spent individuals increased after the sudden drop in water salinity from 30 to 13 ppt after the heavy rainfall, an indication that spawning had occurred. The presence of individuals with spawning stages was also observed throughout of period of sampling which indicates that mussels were continuously breeding in the area. The highest percentage of individuals having spawning stages were recorded in October and November. The information on the factors that affect gonadal maturation and spawning schedule can help mussel growers predict the schedule of spatfall.

Lobocheilos falcifer is a rare and vulnerable freshwater fish species from Java, Indonesia and currently listed as Vulnerable (VU) within the IUCN Red List. In 2019, three specimens of L. falcifer were collected and photographed on Rawa Pening Lake, Semarang Regency, Central Java Province and Solo River, Karanganyar Regency, Central Java Province as two new localities for this species, extending its distribution in about 80 km to southeast. We also provided the morphological data of this species as well.

The main objective of this study was to examine the growth, mortality, and exploitation rate of Chloroscombrus chrysurus from the continental shelf of Ghana, West Africa between July 2018 and June 2019. This study provided results on fishery dynamics parameters to contribute to estimating the stock assessment of these fish species. Monthly length-frequency data were collected from 697 samples and analyzed using fisheries models fitted in TropFish R. The von Bertalanffy growth parameters were utilized to analyze the population dynamics of these species using ELEFAN Simulating Annealing. The estimated asymptotic total length (L∞), coefficient of growth (K), and growth performance index (Φ′) was 24.9 cm, 0.84 year-1, and 2.72, respectively, with a Response surface (Rn) value of 0.79. The total mortality (Z), natural mortality (M), and fishing mortality (F) rates C. chrysurus from the continental shelf of Ghana were 3.27 year-1, 1.31 year-1, and 1.96 year-1, respectively. The exploitation rate (E) estimated was above the optimum level of 0.5 which indicates that the species is overexploited. Based on the Emsy (0.69) value, analyses show that the exploitation rate has exceeded the sustainable limit and hence the need for proper fisheries management measures.

Seeds of Phaseolus vulgaris L. and Pisum sativum were planted in separated pots, then these pots divided into two groups, each group divided into four subgroups. Four different wastewater were used to irrigate the treatments. The results showed the effects induced by irrigated wastewater on P. vulgaris L. and P. sativum. The degree of water salinity induced increasing SOD, protein content and the area of xylem elements, but reduced chlorophyll-α in P. vulgaris. The CAT, protein and chlorophyll-α were increased in in P. sativum as a result to salinity which also reduces the area of xylem elements.

Geometric morphometric method was used to examine the body shape variations among the six populations of Garra rufa, in Iranian part of Tigris basin. A total of 15 landmark-points was used for 170 specimens to hypothesize population differentiation of G. rufa in the six rivers and reservoir. In discriminant function analysis, 85.9% of original grouped cases correctly classified. Principal component analysis (PCA) and canonical variates analysis (CVA) confirmed the significant difference between the populations. The results revealed that the studied populations are divided into three clades based on differences in body depth, caudal peduncle length, backward moving of anal fin. Caudal peduncle showed shortening trend in five populations. Narrower body shape was dominated among specimens of four regions. Studies on body shape provide supporting data on fisheries, stock management, and conservative programs.

Parameters of length-weight relationship of freshwater and marine fishes have long been of interest as a longstanding theme fisheries sciences and have been estimated for many fishes around the world. In this study, for the first time, length weight relationship (LWRs) was estimated for a native fish, the long nose goby, Awaous jayakari (Gobiidae) collected from the inland waters of Oman in 2020. The parameter of b for male and female specimens based on standard length (SL) was within the range of 2.666-4.377 and 2.852-3.374, respectively. As proposed for different fishes there was high and significant correlation coefficients with r 2≥0.97 between length and weight (0.970- 0.983). Bailey’s ‘t’ test revealed that b value significantly deviated from 3 for both males and females showing their positive allometric growth pattern.