Egyptian Journal of Aquatic Research 43 (2017) 291–295

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Egyptian Journal of Aquatic Research

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Full length article Growth and longevity of the mola Amblypharyngodon mola () in the Payra River, southern Bangladesh ⇑ Ferdous Ahamed a, , Zoarder Faruque Ahmed b, Md. Yeamin Hossain c, Jun Ohtomi d a Department of Fisheries Management, Patuakhali Science and Technology University, Bangladesh b Department of Fisheries Management, Bangladesh Agricultural University, Bangladesh c Department of Fisheries, Faculty of Agriculture, University of Rajshahi, Bangladesh d Faculty of Fisheries, Kagoshima University, Kagoshima, Japan article info abstract

Article history: The growth and longevity of Amblypharyngodon mola was studied in the Payra River, southern Received 29 March 2017 Bangladesh, using length-frequency distributions during February 2016–January 2017. Both males and Revised 14 November 2017 females first recruited in June, with modal size around 25 mm standard length. Growth for both sexes Accepted 19 November 2017 was described by the von Bertalanffy growth equation as: L = 50.10[1 exp {0.145(t + 2.926)}] for Available online 27 November 2017 t males and Lt = 51.64[1 exp {0.135(t + 3.326)}] for females. Both sexes showed similar growth patterns as no significant difference was observed between the sexes (F-test, F = 1.89; p = .167). The longevity of Keywords: this was estimated to be 1 + year (13 months for males and 15 months for females). Standard Growth length vs. body weight relationship indicated an isometric growth in both sexes. However, ANCOVA Standard length Length-frequency revealed significant differences in intercept (p < .05) between sexes, though not with slopes (p = .420). Longevity Ó 2017 National Institute of Oceanography and Fisheries. Hosting by Elsevier B.V. This is an open access Amblypharyngodon mola article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction length-weight relationships of A. mola from different water bodies of its distribution area, which are outlined in Table 1. However, The cyprinid fish Amblypharyngodon mola is widely distributed there is no published report on growth of A. mola from any geo- in Indian south Asian countries including Bangladesh, , graphic region where this species is distributed. Therefore, the pre- , Myanmar, and Afghanistan (Coad, 1981; Talwar and sent study aimed to provide information on growth and longevity Jhingran, 1991). This is an important species for the artisanal fish- of A. mola based on monthly length-frequency distributions. In eries of the Indian sub-continent and is an important source of addition, the length-weight relationship was examined for both livelihood for many of the subsistence and artisanal fisher folks sexes. (Talwar and Jhingran, 1991; Jayaram, 1999; Daniels, 2002). There, this fish is highly demandable to consumers due to its good taste Materials and methods and high nutrient value (Alam et al., 2004; Saha et al., 2009) including high protein, vitamin, mineral, Fe, Zn, and Ca content Fish sampling and measurement (Zafri and Ahmed, 1981; Roos et al., 2007; Kongsbak et al., 2008; Mazumder et al., 2008). In Bangladesh, this species has been The present study was conducted in the Payra River running reported as a vital source of micronutrients essential to prevent through Patuakhali, a southern district of Bangladesh (straddling 0 0 malnutrition of rural people, particularly women and children 22° 35 N and 90° 26 E). Monthly samples were collected from (Thilsted et al., 1997). The species is also important as an ornamen- the small-scale, set-bagnet fishery in the Payra River during Febru- tal (aquarium) fish (Gupta and Banerjee, 2012). ary 2016–January 2017. Set-bagnet is a traditional fishing gear Though several studies have been conducted on different bio- similar to trawl net having larger mesh size at mouth and wing, logical aspects including reproduction, feeding ecology and whereas the mesh size gradually decreased to <2 mm and some- times mosquito net at the codend. All collected specimens were preserved in 10% formalin and transferred to the laboratory for Peer review under responsibility of National Institute of Oceanography and analysis. The standard length (SL) of all specimens was measured Fisheries. ⇑ Corresponding author at: Department of Fisheries Management, Patuakhali to the nearest 1 mm using a measuring ruler, whereas weight body Science and Technology University, Patuakhali, 8602, Bangladesh. weight (BW) was recorded using a digital balance to 0.01 g accu- E-mail address: [email protected] (F. Ahamed). racy. Sex determination was done by incision of each individual’s https://doi.org/10.1016/j.ejar.2017.11.002 1687-4285/Ó 2017 National Institute of Oceanography and Fisheries. Hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 292 F. Ahamed et al. / Egyptian Journal of Aquatic Research 43 (2017) 291–295

Table 1 male and female A. mola was described by the von Bertalanffy List of published works in different aspects of Amblypharyngodon mola along with growth equation (von Bertalanffy, 1938): their locations and references.

Aspect Location (water Reference Lt ¼ L1½1 expfKðt t0Þg body/country) Reproduction Mymensingh, Bangladesh Dewan and Doha, where Lt is SL (mm) at age t (month), L1 is asymptotic SL (mm), K is 1979 growth coefficient (year1), and t is theoretical age at zero length. India Mitra and Jain, 1985 0 Andhra Pradesh, India Piska and Waghray, An F-test was conducted to compare the growth curves between 1986 sexes according to Chen et al. (1992): Mymensingh, Bangladesh Kohinoor et al., 2003 Kaptai reservoir, Azadi and Mamun, F ¼½ðSp Sm Sf Þ=r=½ðSf þ SmÞ=ðnm þ nf 2rÞ Bangladesh 2004 Rajshahi, Bangladesh Hoque and Rahman, 2008 where Sm is residual sum of squares (RSS) for males; Sf, RSS of Netrakona, Bangladesh Saha et al., 2009 females; Sp, RSS for pooled data; nm, number of plots for males; nf, Wetland of West Bengal, Gupta and Banerjee, number of plots for females; and r, number of parameters. India 2013a Two floodplain lakes of Mondal and Kaviraj, India 2013 Length-weight relationship Feeding ecology India Das and Moitra, 1963 Andhra Pradesh, India Piska et al., 1991 The relationship between SL vs. BW in both sexes was esti- Bangladesh Miah and Siddique, mated according to Huxley (1932): 1992 Kaptai reservoir, Mamun et al., 2004 lnðBWÞ¼lnðaÞþb lnðSLÞ Bangladesh Wetland of West Bengal, Gupta and Banerjee, where a is intercept and b is slope. A t-test (Sokal and Rohlf, 1987) India 2013b was used to ascertain b value differed significantly from the isomet- Two floodplain lakes of Mondal and Kaviraj, ric value (b = 3), indicating positive (b > 3) or negative (b < 3) allo- India 2013 Rajshahi, Bangladesh Mondol et al., 2013 metric growth (Tesch, 1971). The analysis of covariance (ANCOVA) (Zar, 1984) was conducted to evaluate the significant differences Length-weight Mathabhanga River, Hossain et al., 2006 relationships Bangladesh in slopes and intercepts between sexes. Statistical analyses were Wetland of West Bengal, Suresh et al., 2007 performed using Microsoft Excel-add-in-Solver, Microsoft Excel- India add-in-DDXL and GraphPad Prism 6. Garjan beel, Assam, India Baishya et al., 2010 Padma River, Bangladesh Hossain, 2010 Assam, India Gogoi and Goswami, Results 2014 Wetland of West Bengal, Gupta and Banerjee, A total of the 1193 specimens of A. mola were collected during India 2015 Wetland of Assam, India Devi and Das, 2017 this study, with 558 (46.8%) males and 635 (53.2%) females. The sex ratio showed significant difference from the expected value abdomen and visual inspection of the gonad by naked eye. Then of 1:1, and was found to be slightly in favor of females (male:fe- the gonads were weighed to 0.001 g accuracy. male = 1:1.14, v2 = 4.97, p < .05). The SL ranged from 20.0 to 54.0 mm in males and 20.0 to 58.0 mm in females, whereas BW ranged Length-frequency analysis from 0.11 to 3.53 g and 0.12 to 4.40 g for male and female, respectively. Monthly length-frequency distributions were constructed using 1-mm SL intervals for both sexes. A series of component normal Modal analysis of length-frequency distribution distributions were fitted to the length-frequency data of each sam- ple by sex, using a computer analysis based on Hasselblad’s (1966) Length-frequency distributions for male and female A. mola are maximum-likelihood method. Each component normal distribu- presented in Figs. 1 and 2, respectively. Both male and female were tion was presumed to represent an age group in the population. first recruited in June, with a modal size of around 25 mm SL. The The outputs from this analysis include mean SL, standard devia- length-frequency distributions revealed one to three age groups in tion, and proportion of each age group explained by each compo- each month for both sexes. Only one age group was identified dur- nent normal distribution. ing July for males and April for females due to missing of younger age group or older age groups in that particular month. Two age Determination of birth date and longevity groups were identified in the majority of months for both sexes, whereas three age groups were identified during January for males The gonadosomatic index (GSI) was calculated for each female and January, June, July for females. The length-frequency distribu- individual as GSI =(GW/BW) 100. Then monthly mean GSI was tion showed a discrete new cohort evidently distinguishable from calculated and birth date was assumed to be an arbitrary day in the older individuals, which appeared in June. This newly recruited the month of highest GSI according to Ahmed et al. (2007). Ages cohort of male and females existed until May and July of the sec- (in months) were then calculated for the mean SLs belonging to ond year, respectively. each of the cohorts, and longevity was estimated from the time series of length-frequency distributions. Birth date and longevity

Age assignment and fitting growth curve The monthly variations of mean GSI of female A. mola are shown in Fig. 3. The mean GSI was low in February, then drastically Age was calculated as the time in months intervened from the increased and remained high during April to July, with a peak in assigned birth date to each sampling date. Growth of SLs for both May. Then the GSI began to decrease in August and remained