Truss network based morphometric and meristic variations among south-western populations of Macrognathus aculeatus in Bangladesh

Aim: Landmark-based truss network system was applied to examine the morphometric and meristic differences among four different populaces of Macrognathus aculeatus namely; Dhakuriabeel, Jashore (DBJ); Arial Kha River, Madaripur (AKRM); Nabaganga River, Jhenaidah (NRJ); Kopotakkha River, Jashore (KRJ) in Bangladesh. Methodology: Completely 80 samples of M. aculeatus were collected (20 individuals from each population) for this study. Six meristic characters, 6 morphometric characters and 15 truss-based morphometric characters were measured for one-way analysis of variance (ANOVA) and Tukey-HSD post hoc test. Discriminant function analyses were also performed by using morphometric and truss-based morphometric characters to detect potential characters responsible for population separation. Results: Completely 80 samples of M. aculeatus were collected (20 individuals from each population) for this study. Six meristic characters, 6 morphometric characters and 15 truss-based morphometric characters were measured for one-way analysis of variance (ANOVA) and Tukey-HSD post hoc test. Discriminant function analyses were also performed by using morphometric and truss-based morphometric characters to detect potential characters responsible for population separation. Interpretation: The baseline information derived from the present study would be useful for appropriate conservation of M. aculeatus populations as well as for the researchers for further investigation.

Length-weight relationships of three freshwater eel species from the floodplain ecosystems of northeastern Bangladesh

This study reports the Length-weight relationships (LWRs) of three freshwater eel species from the northeastern wetlands of Bangladesh. A total of 2684 specimens of Mastacembelus armatus, Macrognathus aculeatus and Macrongathus pancalus were sampled between in the months of June and December 2019 using different nets and eel traps at every 4 days working schedule per month. The calculated a values of the LWRs ranged from 0.008 to 0.020; b values ranged from 2.35 to 2.70, and r2 from 0.907 to 0.944. The lowest values of regression coefficient found for M. aculeatus and the highest for M. pancalus. All the regression parameters for LWRs found highly significant (p ˂ 0.001). These results will provide baseline information for sustainable management and conservation of the fisheries resources in the northeastern floodplain region of Bangladesh.

Post-mortem changes in three fresh water eels, Mastacembelus armatus, Macrognathus aculeatus and Mastacembelus pancalus during ice storage

The progress of rigor-mortis and the post-mortem changes in three species of freshwater eelsduring storage at room temperature (30° to 35°C) and ice (0°C) were studied. Rigor-mortis in fish sample atroom temperature, started 1hr after spiking and it reached to a maximum of 76%, 57.14% and 100% within 4hrs after death in Mastacembelus armatus (Baim), Macrognathus aculeatus (Tara baim) and inMastacembelus pancalus (Guchi), respectively. In ice stored eels rigor also started within one hour of spikingand gradually reached to a maximum of 88.89% within 3 hrs in Baim and 85.71%, 100% in Tara baim and inGuchi respectively within 2 hrs. Rigor continued for 17, 14 and 18 hrs in Baim, Tara baim and Guchi,respectively and then started to relax. The pH of the muscle was 6.84, 6.80 and 6.92 immediately after catchin Baim, Tara baim and in Guchi, respectively which decreased gradually with the lapse of storage periodregardless of the storage temperature. The organoleptic quality of eels during ice storage was assessed on thebasis of sensory parameters. Baim was found in acceptable conditions for 24 days whereas Tara baim andGuchi were in acceptable condition for 28 days in ice storage. Percent moisture content increased but proteinand lipid contents decreased in almost all the fish samples with the lapse of storage period but a little changewas observed in ash content. The TVB-N, peroxide and NPN value remained within the recommended valueup to 24 days in Baim and 28 days in Tara baim and Guchi. The initial bacterial loads were 6.5×103,6.2×103 And 6.3×103 CFU/g in Baim, Tara baim and in Guchi, respectively. At the end of the 24 days ofice storage, bacterial load increased in all the fish samples.

Aspects of reproductive biology of the lesser spiny eel Macrognathus aculeatus (Bloch, 1786) from river Ganga, Uttar Pradesh, India

A total of 315 samples of Macrognathus aculeatus (Bloch, 1786) were collected for this study from the river Ganga at Sant Ravidas Nagar, Bhadohi, Uttar Pradesh during June 2016 to May 2017. Chi-square test (χ2) confirmed that the male to female sex ratio was 1:0.93 which was not significantly different from hypothetical ratio of 1:1. The maximum numbers of stage IV gonads were encountered during the month of June indicated its spawning period. Mass and length ratio showed a negative allometric growth (b<3) in males (2.08102), females (2.50212) and for the sexes pooled (2.25371). The maximum and minimum values of condition factor for both the sexes of M. aculeatus were recorded during non-breeding and breeding seasons respectively. The ova diameter of ripe eggs of M. aculeatus ranged between 1.25-1.40 mm during the month of June while the single mean peak value (male =1.40 ± 0.091; female= 4.49 ± 0.059) of the gonado-somatic index of the fish pointed out that the fish has only one breeding season during monsoon. Absolute fecundity varied from 800 to 1510, with an average value of 1247 eggs. Fecundity was found to be highly correlated with the total length (r = 0.9041), body weight (r = 0.8901), ovary length (r = 0.8721) and ovary weight (r 0.9210) which were found to be significant

Analysis of stomach content of piscivorous fishes caught in Danau Panggang Peatland, South Kalimantan, Indonesia

Sofarini D, Herawati EY, Mahmudi M, Hertika AMS, Arfiati D, Musa M, Amin M, Supriharyono. 2019. Analysis of stomach content of piscivorous fishes caught in Danau Panggang Peatland, South Kalimantan, Indonesia. Biodiversitas 20: 3788-3793. The purpose of this study was to analyze the stomach content profile of piscivorous fishes caught at the reservaat station and the station without activity as The control station, in the Danau Panggang peatland. Sampling was carried out four times and the index of preponderance stomach content was determined in piscivorous fishes. The results showed there were nine fish species in the reservaat area, including Cryptopterus spp., Pangasius nieuwenhuisii, Chana striata, Anabas testudineus, Pangasius sp., Mastecembelus erythrotaenia, Macrognathus aculeatus, Mystus nigriceps, and Mystus nemurus. Their gut was dominated 89% by Chrysophyta, and 37.5% by Diatom and Navicula. In the area without activity, six species of fish were caught, including Cryptopterus spp, Pangasius nieuwenhuisii, Anabas testudineus, Pangasius sp, Mystus nigriceps, and Mystus nemurus, with 83% of their gut dominated by Diatom. The water temperature was 28.07-33.25º C, brightness (6-115 cm), pH of 4.23-6.97, dissolved oxygen (DO) (1.4-6.5 mg/L) and BOD (7.52-24.92 mg/L) i.e., water quality parameters that tend to be incompatible with the persistence of fishes. These limiting factors of peatland water and extreme conditions led to a limitation at availability of natural food for piscivorous fishes.

Pengaruh Pemberian Berbagai Jenis Pakan Terhadap Pertumbuhan Dan Tingkat Kelulushidupan Ikan Silih (Macrognathus aculeatus) [The Effect Of Vary Feed On Growth And Survival Rate Of Spiny Eel (Macrognathus aculeatus)]

The purpose of this research was to know the effect of kinds of feeding on growth and survival rate of spiny eel. This research used experimental method and Completely Random Design method with six treatment and each treatment was replicated four times. The treatments are : artificial feed (A), nila fish (B), shrimp (C), combination of artificial feed with nila fish (D), combination of artificial feed with shrimp (E) and combination of nila fish with shrimp (F). The main parameter observed are specific growth rate, growth of absolute length and survival rate. The support parameter is water quality. The data analiysis of this research used a Analysis of Varian (ANAVA) and to determine the best performed used Duncan’s Multiple Range test. The result of this research showed that given kinds of feeding was not significantly difference (p>0,05) to specific growth rate, growth of absolute length and survival rate of spiny eel. The average value of growth of absolute length, specific growth rate and survival rate of each treatment are treatment C (2,5062 mm), treatment C (0,9375 %BT/hari) and treatment C (71,6495%).