Estimation of life history parameters for river catfish Eutropiichthys vacha: insights from multi-models for sustainable management.

The river catfish, Eutropiichthys vacha is a vital protein source for rural communities and has high commercial value, but understanding its life history and management strategies reveals major inadequacies and ambiguities in the riverine ecosystems. Consequently, this study employs multi-models to analyze the life history parameters of E. vacha in the Ganges River (northwestern Bangladesh) from January to December, 2020. The total length (TL) and body weight (BW) of 362 individuals (male = 170, female = 192) were measured by a measuring board and a digital weighing balance, respectively. The overall sex ratio (male: female) was 1.0: 1.13 and did not oscillate statistically from the standard 1:1 ratio (p > 0.05). The TL varied from 6.7-19.2 cm for males and 6.3-19.0 cm for females. The length-frequency distributions (LFDs) revealed females outnumbered in 8.0-9.99 cm TL whereas males in 7.0-7.99 cm TL. The slope (b) of the length-weight relationship (TL vs. BW) for both sexes (b = 2.87) was substantially lower than isometry, specifying negative allometric growth pattern for E. vacha. Sex-specific relative (K R ) and Fulton's (K F ) condition analysis revealed better state of well-being of males than females. Only K F exhibited significant correlation with both BW and TL, hence making it ideal condition for predicting the fitness of E. vacha in this river. Moreover, the relative weight (W R ) suggests an imbalanced habitat for females with higher abundance of predators but suitable for males. The form factor (a 3.0 ) was 0.0062 and 0.0065, whereas the size at first maturity (L m ) and mean natural mortality (M W ) were 11.38 and 11.27 cm TL and 1.29 and 1.28 year-1 for the respective sexes. Besides, the calculated mean optimum catchable length (L opt ) was 13.58 and 13.09 cm TL for each sex. These findings will be crucial for further studies and to recommend appropriate strategy for the sustainable management of E. vacha in the Ganges River and adjacent watersheds.

Assessing the exploitation status of main catfish Eutropiichthys vacha based on length based stock assessment models in the Kaptai Lake from Bangladesh.

The current study focuses on the detailed data on stock assessments including population structure, growth parameters, mortality, recruitment pattern, exploitation rate (E), maximum sustainable yield (MSY) and relative yield per-recruit of Eutropiichthys vacha (Hamilton, 1822) based on 2512 specimens through regular monthly sampling using gill net, cast net, and square lift net in the Kaptai Lake, located in the hilly region of Bangladesh during January to December 2017. Total length (TL) and body weight (BW) were measured using digital slide calipers and electronic balance with 0.01 cm and 0.01g accuracy for each individual. The asymptotic length (L ∞) was 44.40 cm and growth coefficient (K) was 0.70 year-1. The growth performance index (Ø') was 3.14. The age at zero length (t 0 ) was 0.027 year and life-span (t max ) was 2.73 year. We estimated total mortality (Z), natural mortality (M) and fishing mortality (F) as 4.23, 1.27 and 2.96 year-1, respectively. The recruitment pattern was throughout the year with two pick-events during May and September. Length at first capture (L c ) was 20.65 cm TL. The E was 0.70 where the E max (exploitation rate producing maximum yield) was 0.45 which indicates 25% over fishing. The MSY was estimated as 34257 metric ton. In conclusion, the results of this study would be very operative to execute specific management for E. vacha in Kaptai Lake, Hilly region of Bangladesh.

Climato-environmental influence on breeding phenology of native catfishes in River Ganga and modeling species response to climatic variability for their conservation.

The main objectives of the present study were to quantify the environmental, especially temperature and rainfall, effects on breeding phenology of selected catfish species and to predict changes in breeding phenology of the selected species in relation to climatic variability for the Ganga River Basin. The study showed that changes in rainfall pattern may have the most profound effect on gonad maturation and breeding of Mystus tengara and Mystus cavasius followed by the effect of increased water temperature due to rising air temperature. Indication of region-specific adaptation was noticed in reproductive phenology of Eutropiichthys vacha based on local trends of warming climate. The other habitat parameters, such as dissolved oxygen, alkalinity, nitrate, and phosphate, were correlated with gonad maturity and spawning. Climatic variability may bring region-specific changes in breeding phenology of fish species in the Ganga River. Under a warming climate, changes in precipitation pattern manifested into riverine flow pulse may be the key driver in dictating breeding phenology. Our study indicates E. vacha as a climate sensitive species that may be selected as a target species for climate change impact studies.

Reproduction of Eutropiichthys vacha (Schilbeidae) in the Ganges River (NW Bangladesh) with special reference to potential influence of climate variability.

The Batchwa vacha, Eutropiichthys vacha is commercially important, supporting a viable small- and large-scale fishery throughout the Ganges River, NW Bangladesh. This study provides detail information on reproduction of E. vacha including size at sexual maturity, spawning and peak spawning season, and fecundity based on 734 female specimens through regular monthly sampling using cast net, gill net, and square lift net in the Ganges River during January to December 2016. Also, our study estimated the effects of climate change including temperature and rainfall on reproduction of E. vacha in the Ganges River. For each individual, lengths (total length, TL; standard length, SL) and body weight (BW) were measured with slide caliper and digital balance, respectively. Gonads (ovaries) were collected carefully by ventral dissection of each female specimen and weighed to the nearest 0.01 g accuracy. The gonadosomatic index (GSI % = (GW/BW) ×100), modified gonadosomatic index (MGSI % = (GW/BW - GW) × 100), and Dobriyal index (DI = [Formula: see text]) were calculated to estimate the size at sexual maturity (L50) and spawning season. Based on GSI, MGSI, and DI, the L50 was calculated as 12.5 cm TL for female. The TL50, the TL at which 50% of individuals become mature, was calculated by logistic equation as 12.7 cm. Also, on the basis of higher values of GSI, MGSI, and DI, spawning season was ranged from April to August, with the peak in June-July, signifying the peak spawning season for E. vacha in the Ganges River. The total fecundity (FT) ranged from 4800 to 77,976 (mean ± SD, 31384 ± 23,747) and was highly correlated with TL and BW. Water temperature during the spawning period ranged from 28 to 34 °C, with an average of 31 °C and there was significant correlation between temperature and GSI. Also, the spawning season coincides with the peak rainfall and there was significant correlation between rainfall and GSI. Additionally, analysis of long data series indicated that annual average air temperature is increasing by 0.0258 °C/year, while the annual average rainfall is decreasing by 3.107 mm/year. Finally, the findings of this study would be very effective to impose specific management for E. vacha in the Ganges River and surrounding ecosystems.

Benchmarking pre-spawning fitness, climate preferendum of some catfishes from river Ganga and its proposed utility in climate research.

The concept of threshold condition factor (Fulton), beyond which more than 50% of the female fish population may attain readiness for spawning coined as pre-spawning fitness (K spawn50), has been proposed in the present article and has been estimated by applying the non-parametric Kaplan-Meier method for fitting survival function. A binary coding strategy of gonadal maturity stages was used to classify whether a female fish is "ready to spawn" or not. The proposed K spawn50 has been generated for female Mystus tengara (1.13-1.21 units), M. cavasius (0.846-0.945 units), and Eutropiichthys vacha (0.716-0.799 units). Information on the range of egg parameters (fecundity, egg weight, egg diameter) expected at the pre-spawning stage was also generated. Additional information on species-specific thermal and precipitation window (climate preferendum) within which K spawn50 is attained was also generated through the LOESS smoothing technique. Water temperatures between 31 and 36 °C (M. tengara), 30 and 32 °C (M. cavasius), and 29.5 and 31 °C (E. vacha) and monthly rainfall between 200 and 325 mm (M. tengara), > 250 mm (M. cavasius), and around 50 mm and between 350 and 850 mm (E. vacha) were found to be optimum for attainment of K spawn50. The importance of parameterization and benchmarking of K spawn50 in addition to other conventional reproductive biology parameters has been discussed in the present article. The purposes of the present study were fulfilled by generating baseline information and similar information may be generated for other species replicating the innovative methodology used in this study.

Complete mitochondrial genome of catfish Eutropiichthys vacha (Hamilton, 1822).

Complete mitochondrial genome of catfish, Eutropiichthys vacha, was isolated by LA PCR (TakaRa LAtaq, Dalian, China); and sequenced by Sanger's method to obtain the complete mitochondrial genome, which is listed Critically Endangered and Red-listed species. The complete mitogenome was 16,478 bp in length and contains 13 typical vertebrate protein-coding genes, 2 rRNA and 22 tRNA genes. The whole genome base composition was estimated to be 31.06% A, 27.59% C, 15.65% G, and 25.68% T. The complete mitochondrial genome of catfish, E. vacha provides the fundamental tool for genetic breeding and conservation studies.

Fate of ß-asarone in Ayurvedic Sodhana process of Vacha.

BACKGROUND: Calamus (Acorus calamus Linn., Araceae) rhizome synonymously called sweet flag or Vacha is an aromatic herb indigenous to Central Asia and Eastern Europe. It has been used by the Ayurvedic practitioners since time immemorial for diseases ranging from weakness of memory to being used as an anthelminthic. Reports of its use have been found in books like Charak Samhita, Sushruta Samhita, etc., The major constituent of the oil of Vacha is a phenyl propanoid called ß-asarone, which is reported to show carcinogenic properties. Due to the toxic effects of ß-asarone, sodhana prakriya (detoxification process) has been prescribed for Vacha before its inclusion in the Ayurvedic medicines. Shodhanaprakriya (S. prakriya) of Vacha has been mentioned in the Ayurvedic texts. OBJECTIVES: This study was undertaken with an aim to find out the mechanism involved in the S. prakriya of Vacha and also to suggest an alternate method for the conventional one. MATERIALS AND METHODS: The conventional method was studied in the laboratory and equivalent alternate methods were designed based on the mechanism involved. Vacha samples were subjected to the conventional method as well as the alternate methods and the content of ß-asarone in the different samples was monitored using Gas Chromatography technique. RESULTS: Various alternate methods have been devised based on the mechanism involved in the S. prakriya which have given results comparable with those of the conventional method. CONCLUSION: The scientific mechanism involved in the S. prakriya of Vacha has been established and alternate methods have been proposed.

Anticonvulsant activity of raw and classically processed Vacha (Acorus calamus Linn.) rhizomes.

The rhizome of Vacha (Acorus calamus) has been used in Ayurvedic medicine for the treatment of various ailments, such as epilepsy, headache, eye disorders, insomnia, loss of memory, etc. Previous studies demonstrated that Vacha rhizome is having significant anticonvulsant activity against various induced seizures models in experimental animals. Ayurvedic pharmacopoeia of India has advocated Shodhana (purificatory procedures) to be done prior to its use. In the present study a comparative anticonvulsant activity of raw and Shodhita (classically processed) Vacha rhizomes were screened against Maximal Electro Shock (MES) seizure model to assess the effect of classical purificatory procedure on pharmacological action of Vacha. Phenytoin was used as standard antiepileptic drug for comparison. Pretreatment with both raw and classically processed Vacha samples exhibited significant anticonvulsant activity by decreasing the duration of tonic extensor phase. Further classically processed Vacha statistically decreased the duration of convulsion and stupor phases of MES-induced seizures. The results obtained from the present study clearly confirmed the anticonvulsant activity of raw Vacha and subjecting to classical Shodhana procedure did not alter the efficacy of Vacha rhizomes instead it enhanced the activity profile of the Vacha.

Experimental evaluation of antidepressant effect of Vacha (Acorus calamus) in animal models of depression.

Depression is a common diagnosis throughout India. It is one of the major sequelae of modern lifestyle which is full of stress. Several drugs and therapies have been tried but a safe and effective treatment of depressive illness is yet not fully established. The main objective of this experimental study on animal models is to evaluate the antidepressant action of plant drug Vacha (Acorus calamus). The behavioral study was conducted and at the same time 5-HT receptor involvement was evaluated. The experimental study was done in rats to evaluate their Open Field Behavior (OFB), High Plus Maze (HPM) activity and 5-hydroxytryptamine (5-HT) receptor syndrome, before and after feeding Vacha. Concurrent Vacha administration in the depression model prevented the development of behavioral deficit in ambulation and rearing due to stress. Similarly, in High Plus Maze Test (HPMT), exploratory activity of rat was restored with Vacha administration. In adopted model of depression, when the animal was subjected to Vacha administration, the behavioural deficit was prevented very well as compared to stressed group. While eliciting the 5-HT syndrome, only two components out of five were influenced by Vacha, indicating that Vacha does not sensitize postsynaptic 5-HT1A receptors, which explains the behavioral deficit prevention in stressed rat group. Vacha definitely has antidepressant effects in animal model of depression.