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Distribution of b values of (a) LWR and (b) LLR for all the species and from all the Rivers considered in the current study. Both the plots show good fit for the normal distribution.
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p>Length-weight (LWR) and length-length (LLR) relationships of seven loach species (Teleostei: Cypriniformes): Botia striata, Lepidocephalichthys thermalis, Paracanthocobitis mooreh, Indoreonectes evezardi, Nemacheilus anguilla, Nemachilichthys rueppelli and Schistura denisoni were studied from five localities within the Krishna River system of the...
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Context 1
... the investigated species for all sites ranged between 2.72 to 3.92 (Table 3). There was considerable variation in the LWR b values across species and across sites for the same species (Fig. 2a). The distribution of LWR b values for all the species from all different sites followed a Gaussian curve with a mean of 3.11 and standard deviation 0.21 (Fig. 3a). The mean value of LWR b was significantly larger than cubic value (t = 7.99, df = 4, P = ...
Context 2
... b value of LLR ranged between 0.96 to 1.06 (Table 4). There was considerable variation in the LLR b values across species and across sites for the same species (Fig. 2b). However, the distribution of LLR b values for all the species from all different sites followed a Gaussian curve with a mean of 0.98 and standard deviation 0.03 (Fig. 3b). The mean value of LLR b was significantly lower than unity as expected by isometry (t = 3.08, df = 4, P = ...
Context 3
... the populations studied in the present case are from relatively less polluted areas as compared to the populations studied by Kharat et al. (2008), andKharat & Dahanukar (2013). The distribution of b values of LWR and LLR followed a normal distribution with a mean significantly different from three and unit values for LWR and LLR respectively (Fig. 3). The mean b value for LWR was significantly larger than expected for isometry, indicating that the increment in the weight is more per unit increment in the length. This indirectly suggests that the loaches in the studied sampling locations are quite healthy. The mean b value for LLR was significantly lesser than unity as expected by ...
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Citations
... which exhibited negative allometry. Nonetheless, the negative allometry observed in juvenile fish may be considered unreliable due to the limited number of immature fish in our sample, as the sample size can also influence the estimation of the allometry coefficient (Keskar et al. 2015). Consequently, based on the findings of this study, it can be concluded that the bogue population in Mersin and Iskenderun Bays showed positive allometric growth. ...
The bogue (Boops boops (L. 1758)), is a commercially important fish species listed within top landed marine species in Turkish fisheries. This study was performed to assess feeding, growth, mortality, and level of exploitation of the population in Mersin and Iskenderun Bay, in the Eastern Mediterranean Sea. The ratio of males to females (1:1.04) was not significantly different from 1:1. The growth profile was positive allometric, except for juveniles. The von-Bertalanffy growth parameters for the combined sexes were L∞ = 32.991 cm, k = 0.181 years⁻¹ and t0 = -1.928 years, and growth performance index was Ø = 5.286. Total mortality (Z) was estimated as Z = 1.402, with natural mortality (M) and fishing mortality (F) of M = 1.162 and F = 0.829, respectively. The exploitation ratio was calculated as E = 0.829, indicating that bogue stock that inhabits Mersin and Iskenderun Bay was overexploited. Fishing pressure should therefore be reduced in order to preserve the population. A total of 190 stomach contents were analysed, of which 46 (24%) contained undigested food. The diet consisted of larval and juvenile fish, copepods, shrimps, and squids. The larval and juvenile stages of the invasive Bregmaceros nectabanus were the most prevalent prey items, occurring in 95% of the examined specimens with full stomachs. This serves as a notable example of how an invasive species can emerge as a vital dietary component for native species.
... The LWR pattern helps to know the relationship between body size and shape. Through LWR and Kn, fish production, stocking density, maturity, spawning can be calculated (Ama-Abasi, 2007;Keskar et al., 2015;Gohain and Deka, 2017;Biswas et al., 2018). The present study recorded 'b' values in the range of 5.5 -5.7 which is greater than the theoretical 'b' value 3 (cube law). ...
The commercial rearing technique for Indian spiny loach is yet to be standardized. Therefore, a 45-days preliminary study was undertaken in two different pond conditions i.e., lined pond without sand substratum (treatment-1) and lined pond with sand substratum (treatment-2) to evaluate the growth performance and length-weight relation of Lepidocephalichthys thermalis. For this, loach fish (2.0-2.3 cm and 0.006-0.009 g) were collected from natural collection sites and, after proper acclimatization, they were stocked in the prepared experimental ponds. In each pond, 250 number of loach fish were stocked at the early morning and feed with supplementary feed at ad libitum level. At the end of trial, significant difference was found in growth performance of fishes reared in two different pond conditions, except survival rate. Significantly higher final weight (0.5253±0.002 g), specific growth rate (10.80±0.01%/ day), weight gain (0.52±0.002 g), weight gain percentage (7280.82±32.12%) and gross biomass (76.70±0.81 g) were recorded in the treatment-2 reared fish. Survival rate was in the range of 96±0.67 to 98±0.67% between two groups. The calculated equation for LWR of loaches as follows, W = 0.00153*L5.561, r2-0.9806 and W = 0.000124*L5.708, r2-0.9823 for fish reared in treatment-1 and treatment-2, respectively. Between the two treatments, the b value was found to be highest in treatment-2 reared fish. Further, the results of this study showed positive allometric growth in both treatments. The k factor value of was recorded lower (0.57) in treatment-1 group. On the other side, the lined pond provided with sand substratum exhibited higher k factor and it was recorded as 0.75. Overall, the present preliminary study results indicate that L. thermalis can be cultured in a controlled environmental pond conditions with sand substratum. However, further studies are needed to improve farming practices with different farming systems and conditions.
... km (Dahanukar, 2011). Because of the current decline in habitat area, size and/or quality, indirect impact of destructive fishing practices and dubious information on population trend, the zebra loach has been listed as endangered in the IUCN Red List of Threatened Species (Dahanukar, 2011;Keskar, Kumkar, Paingankar, Padhye, & Dahanukar, 2015;Keskar, Raghavan, Kumkar, Padhye, & Dahanukar, 2017). Despite its threatened status, India's zebra loach trade volume contained more than 382,575 individuals and ranked second in the volume of trade in aquarium pets (Raghavan et al., 2013). ...
... There is a lack of knowledge about zebra loach reproduction, which hinders efforts at artificial breeding and commercial farming to meet global demands for aquarium sales and reduce the harvesting of wild populations. Zebra loach are also susceptible to artisanal fishing, which affects their survival because of the use of destructive techniques such as dynamite fishing (Keskar et al., 2015(Keskar et al., , 2017. As a result, fishers have seen a rapid decrease in the wild zebra loach population, predicting the extinction of this species in the near future. ...
... It is evident from the present investigation that the current level of zebra loach export is unsustainable, but efforts towards conservation of the fish are fraught with significant social, economic, cultural, biological and political challenges. For instance, the zebra loach forms a large part of the local subsistence fisheries and provides a wide range of societal benefits (Keskar et al., 2015(Keskar et al., , 2017, employment and food security for millions of rural poor in its range. We do not have a method for differentiating between commercial and subsistence fisheries of zebra loach and it is difficult, therefore, to implement a single management strategy to accomplish both conservation and a sustainable trade in zebra loach. ...
Countless animals, including threatened species from invertebrates to vertebrates, are the victims of the world's largest illegitimate business—illicit sales of wildlife. Botia striata (zebra loach) is an endangered freshwater fish endemic to the Western Ghats of India. Because of its distinctive stripes, it is heavily exported and ranks second in the volume of trade in aquarium pets from India. However, maintaining a sustainable aquarium trade is a complex task which depends on the availability of authentic data on the volume of trade, trade routes and the supply chain of the species involved. In this study, therefore, we collected five years of trade data including daily exports of zebra loach from India's international airports to identify the global centers for its trade, its exact traded volume and trade routes. To support artificial breeding programs of zebra loach, the breeding season and size at first maturity were also determined. Using reproductive biology data, the number of individuals traded during the breeding season and the total contribution of immature individuals to the trade were also determined. Results revealed that 265,610 zebra loach were exported from five exit points in India to sixteen different countries (global centers in Asian countries). The greatest number of consignments was from Kolkata, which makes it the top exit point for the zebra loach trade. Singapore is the top importer (73.05 %) of zebra loach and thus probably acts as a transit hub for the distribution of zebra loach individuals across the globe. About 60% of the zebra fish were exported during the breeding season suggesting that the global aquarium pet trade may increase the fish’s risk of extinction. Our global maps of trade centers of the study species would serve as “The past as a guide to the future”. The present study indicates that sustainable trade in wildlife can be achieved if laws are enacted and enforced to require information on traded species, support functional artificial breeding programs, include species of conservation concern into CITES appendices and ensure strict enforcement of laws to preserve biodiversity.
... The "b" value of S. fasciata is almost similar to the specimens' data from the Simsang River in Meghalaya, India (Talukdar et al., 2017). Many authors reported 'b' values and correlation coefficients (r 2 ) for different sister species of Schistura which are very closed to our present findings (Akhtar & Khan, 2018;Ansumal & Subba, 2009;Froese & Pauly, 2019;Keskar et al., 2015;Negi, 2013;Talukdar et al., 2017). Correlation coefficients (r 2 ) value of the present study (between 0.9 and 1.0) indicated ideal growth of all species (Hanif et al., 2020). ...
The length weight relationships of six Nemacheilid species Schistura chindwinica (Tillak & Hussain, 1990), Schistura fasciata Lokeshwor & Vishwanath, 2011, Schistura khugae Vishwanath and Shanta, 2004, Schistura minuta Vishwanath & Shanta Kumar, 2006, Schistura reticulata Vishwanath & Nebeshwar Sharma, 2004 and Schistura rubrimaculata Bohlen & Ŝlechtová, 2013 sampled from Leimatak, Barak, Chakpi, Ayai, Duta, Maklang, and Taret River, in Manipur, India were studied. Samples were collected using fishing gear (cast nets) and electro fishing. The b values in the LWRs were estimated as 2.786 for S. chindwinica, 3.098 for S. fasciata, 3.000 for S. khugae, 3.142 for S. minuta, 2.992 for S. reticulate and 3.168 for S. rubrimaculata. Present study recorded maximum length for five species except S. chindwinica.
... The "b" value of S. fasciata is almost similar to the specimens' data from the Simsang River in Meghalaya, India (Talukdar et al., 2017). Many authors reported 'b' values and correlation coefficients (r 2 ) for different sister species of Schistura which are very closed to our present findings (Akhtar & Khan, 2018;Ansumal & Subba, 2009;Froese & Pauly, 2019;Keskar et al., 2015;Negi, 2013;Talukdar et al., 2017). Correlation coefficients (r 2 ) value of the present study (between 0.9 and 1.0) indicated ideal growth of all species (Hanif et al., 2020). ...
The length‐weight relationships (LWRs) of six Nemacheilid species (Schistura chindwinica, S. fasciata, S. khugae, S. minuta, S. reticulata and S. rubrimaculata) have been analyzed. Fish samples were collected on quarterly basis from March 2018 to February 2019. Sampling was performed using cast nets (mesh size 5–10 mm; about 50 sq m area covered each time and water depth was 4 ft approx.), and electrofishing (Ultrasonic Inverter Electro Fisher, 24 volts, 4 m) in the day time. The total length (TL) of individual fish was measured to 0.1 cm with a digital caliper and body weights (BW) were measured to 0.001 g with digital electronic balances. The parameters for the LWR equations were calculated, and the respective statistics such as the 95% confidence interval for parameters “a” and “b” are provided as well as the coefficient of correlation. For five species a new maximum total length has been documented.
... The present study uses head length (HL) along with TL and SL to establish linear regression; however they used fork length (FL). Our study on the LLR of Botia dario is also in a similar trend for LLR of seven species of loach namely Botia striata, Lepidocephalichthys thermalis, Paracanthocobitis mooreh, Indoreonectes evezardi, Nemacheilus anguilla, Nemachilichthys rueppelli and Schistura denisoni (Keskar et al, 2015). Since the species of loaches have an elongated body structure, ecological studies that can investigate the effect of shape on the LLR could shed more light on the non-isometric relations in LLR. ...
The present study documents the relationship between total length (TL) and live body weight (BW) and relationship between total length (TL), standard length (SL) and head length (HL) for four native fish species from Barak River, Assam, India. The relationship between TL, SL and HL was found to be linear for all cases. The b value for all the five studied fish species ranged from 2.47 to 3.14. No previous record on length-weight relationship (LWR) and length-length relationship (LLR) of these five fish species from Barak River, Assam has been found in Fish Base.
... In the northern region of the Western Ghats, a globally important ecoregion for freshwater fish diversity and endemism many native species of loaches are caught and sold by an indigenous tribal community called the Katkarifor whom fishing is one of the most profitable livelihood option and principal source of subsistence (Patnaik, 2004). This exploitation is however on-going despite suggestions by previous studies on the decline of loaches in this region (Kharat and Dahanukar, 2013;Keskar et al., 2014Keskar et al., , 2015. ...
... All populations, irrespective of their anthropogenic impacts, showed a significantly (two tailed t test, P < 0.008) higher b value of LWR, as compared to cubic value expected from isometric growth, except for only L. thermalis population from Bhor (i.e. the low anthropogenic impact area, P = 0.7274) ( Table 1). This indicates that the weight of the fish grew with higher increments while the standard length grew with smaller increments, a result consistent with an independent study (Keskar et al., 2015) based on nonoverlapping samples. In general, populations from low anthropogenic impact area showed relatively higher asymptotic length (L ∞ ), length of first capture (L c ) and lower fishing mortality and exploitation as compared to populations from high anthropogenic impact areas ( Table 2). ...
... Further, we could also not record good catches of I. evezardi, P. mooreh and S. denisoni from the high anthropogenic impact areas, from where these species were previously reported to occur in moderate numbers (Kharat et al., 2001;Dahanukar et al., 2012). Although several anthropogenic stressors have been identified as potential threats to fish populations in the study area (Kharat et al., 2003;Dahanukar et al., 2011Dahanukar et al., , 2012Keskar et al., 2014Keskar et al., , 2015, there has not been any quantitative evidence as yet to understand species-specific impacts. However, in this study, we provide the first evidence that unmanaged Our results suggest that small fish species are vulnerable to overexploitation in subsistence fisheries, unless management interventions are implemented. ...
Small, least conspicuous fish species are targeted through subsistence fisheries in many regions of the world, but little is known about their population dynamics or exploitation levels. In the Western Ghats of India, part of a global biodiversity hotspot and an exceptional region of freshwater fish diversity and endemism, several small species of loaches are caught and sold in the local markets by marginalized communities through an unmanaged fishery, resulting in high levels of exploitation. Of particular concern is the fishery for the spiny loach, Lepidocephalichthys thermalis whose exploitation rates at various sites in the northern part of the Western Ghats region were observed to be greater than their E50 (exploitation rate where the stock is reduced to half its virgin biomass). A comparison of various fishing sites showed that populations in the high anthropogenic impact areas (located close to urban settlements with high human population density, and impacted by various threats, i.e. introduced species, pollution) are exploited at a rate greater than 86% of their Emax (exploitation producing maximum yield). The first quantitative information on population dynamics and exploitation levels of small indigenous fish species in tropical rivers indicates their potential vulnerability to over fishing, and is an important starting point for further investigations into similar fisheries in other regions of Asia and Africa.
... The present study uses head length (HL) along with TL and SL to establish linear regression; however they used fork length (FL). Our study on the LLR of Botia dario is also in a similar trend for LLR of seven species of loach namely Botia striata, Lepidocephalichthys thermalis, Paracanthocobitis mooreh, Indoreonectes evezardi, Nemacheilus anguilla, Nemachilichthys rueppelli and Schistura denisoni (Keskar et al, 2015). Since the species of loaches have an elongated body structure, ecological studies that can investigate the effect of shape on the LLR could shed more light on the non-isometric relations in LLR. ...
The present study documents the relationship between total length (TL) and live body weight (BW) and relationship between total length (TL), standard length (SL) and head length (HL) for four native fish species from Barak River, Assam, India. The relationship between TL, SL and HL was found to be linear for all cases. The b value for all the five studied fish species ranged from 2.47 to 3.14. No previous record on length-weight relationship (LWR) and length-length relationship (LLR) of these five fish species from Barak River, Assam has been found in Fish Base.
... Identification of three selected genus is difficult to identify only on the basis of morphological and anatomical characteristics. Till date, there is scarce information available regarding the ecology, biology and allometry of these loaches [18]. For the present investigation, morphological and molecular identification, like the polymerase chain reaction (PCR)-based RAPD, ISSR, AFLP and DNA barcoding techniques were used. ...
Genus Nemacheilus, Nemachilichthys and Schistura belong to the family Nemacheilidae of the order Cypriniformes. The present investigation was undertaken to observe genetic diversity, phylogenetic relationship and to develop a molecular-based tool for taxonomic identification. For this purpose, four different types of molecular markers were utilized in which 29 random amplified polymorphic DNA (RAPD), 25 inter-simple sequence repeat (ISSR) markers, and 10 amplified fragment length polymorphism (AFLP) marker sets were screened and mitochondrial COI gene was sequenced. This study added COI barcodes for the identification of Nemacheilus anguilla, Nemachilichthys rueppelli and Schistura denisoni. RAPD showed higher polymorphism (100%) than the ISSR (93.75-100%) and AFLP (93.86-98.96%). The polymorphic information content (PIC), heterozygosity, multiplex ratio, and gene diversity was observed highest for AFLP primers, whereas the major allele frequency was observed higher for RAPD (0.5556) and lowest for AFLP (0.1667). The COI region of all individuals was successfully amplified and sequenced, which gave a 100% species resolution.
