Int. J. Aquat. Biol. (2013) 1(4): 143-149 E-ISSN: 2322-5270; P-ISSN: 2383-0956 Journal homepage: www.ij-aquaticbiology.com © 2013 Iranian Society of Ichthyology Original Article An investigation on morphology, age and growth of the Caspian Sea Kilka (Clupeonella cultriventris) in Babolsar, southern Caspian Sea Zohreh Mazaheri Kohanestani *1, Rasoul Ghorbani1, Saeid Yelghi2, Abdolazim Fazel3, Mahmood Zoghi1 1 Department of Fisheries, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. 2 Gorgan Research Center of Inland Water Fishes, Gorgan, Iran. 3 Department of Fisheries, University of Guilan, Guilan, Iran. Abstract: In this study, 160 fishes were randomly collected from commercial catch by a cone net in Babolsar Port from January to October 2010. The biological features of specimens were measured. 2 + years old fishes made the dominant age group with 33.75% and 1+ and 5+ years old had the least frequency (8.75%). Relationship between length and weight indicated negative allometric growth pattern (b=2.581). The Von-Bertalanffy growth parameters were calculated as L=131.57 mm, k=0.26 and t0=-1.02. Growth performance index was 1.66 and the total mortality (Z), natural (M) and fishing (F) mortality coefficients were 0.9 year, 0.43 and 0.47, respectively. The exploitation ratio (E) was calculated as 0.52. Introduction Identification of fishes is the first stage to manage the aquatic ecosystem and conservation of the stocks (Yaoungs and Robson, 1978). Kilka belongs to the species Clupeonella and Clupeidae or Herring family. There are three genus of Kilka in the Caspian Sea including common Kilka (Clupeonella cultriventris), anchovy (Clupeonella engrauliformis) and Big-eye Kilka (Clupeonella grimmi) that are identified by morphometric parameters (Anonymous, 1978). Kilka is fished by cone nets using under water light to attract fishes at nights (Yermalchev and Sedov, 1990; Fazli and Rouhi, 2002). Kilka has an important role in the Caspian Sea ecosystem and costal countries economic. They are considered as an important part of the trophic chains (Mamedov, 2006) and also a health indicator of the Caspian Sea environment (Fazli, 1990; Razavi Sayyad, 1993; Pourgholam et al., 1996). Their stocks are needed to be protected (Pourgholam et al., 1996). * Corresponding author: Zohreh Mazaheri Kohanestani E-mail address: zohremazaheri_65@yahoo.com Article history: Received 8 May 2013 Accepted 27 June 2013 Available online 2 0 August 2013 Keywords: Morphology Growth Natural and Fishing Mortality Caspian Sea Since 1998, Kilka populations have decreased due to invasion of Mnemiopsis leidyi as a new trophic rival, chronic poisoning with oil, phenol and heavy metal pollutants, temperature variation of the Caspian Sea and over-fishing (Paritskii et al., 2001). Mnemiopsis leidyi has already damaged the pelagic ecosystem of the central and southern Caspian Sea, directly or indirectly impacting all trophic levels. Previous studies confirm decline of Kilka biomass in some neighbor countries as Mamedov (2006) reported that exploitable biomass of Kilka varied from 18500t to 5100t between 2000-2004 in Azerbaijan. Since Kilka is an important part of diet of some valuable fishes like sturgeon (Acipenser spp. and Huso huso) and seal (Phoca caspica), decline of its biomass can threat their stocks. There are some studies on distribution (Besharat and Khatib, 1993; Razavi Sayyad, 1993), stock assessment (Pourgholam et al., 1996; Fazli et al., 2002) and biology (Karimzadeh et al., 2010; Fatemi 144 Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 et al., 2009; Parafkandeh Haghighi, 2009; Fazli et al., 2002, 2004, 2005, 2007; Sayyad Bourani, 1997) in Kilka of southern part of the Caspian Sea. The present study aimed to provide a renew of information on biological characteristics of Clupeonella cultriventris in southern part of the Caspian Sea. Such information may help to manage Kilka stocks. Materials and Methods This study was carried out from January to October 2010. 160 samples were randomly collected from the commercial catches, which taken by fishing boat and cone nets with a 1500 kW light to attract the fish in Babolsar Port, the southern part of Caspian Sea. Samples were preserved in 10% formaldehyde and transported to laboratory. Weight and standard length were measured by a digital scale (0.01 g) and vernier calipers (0.01 mm), respectively. Age was determined using annuli of 10 scales. In order to increase precision of age determination, scales were examined by 3 experts and, in some cases, compared with otolith. Relationship between length and age estimated using regression model. The standard Von Bertalanffy growth equations and Ford-Walford method were used to estimate growth in each age (Bagenal and Tesch, 1978; Erdogan, 2002): Lt = L∞ (1-e-K (t-t0)) Where Lt is the length-at-age t, L∞ is the maximum theoretical length, k is growth coefficient and t0 is equal to age of fish when the length is zero. The growth performance index was calculated using the following equation (Pauly and Munro, 1984): φ´= Log k +2 Log L∞ The condition factor (CF) and instantaneous growth rate (G) was calculated, respectively, as: CF = W/L3 and G = (Lnw2-Lnw1)/(t2-t1) Where W1 = initial wet weight of fish, W2 = final weight of fish, t1 = age at stocking and t2 = age at end of the period (usually one year). Total morality (Z) was calculated based on Beverton and Holt (1956) method follow as: ( L  Lc) Z= K[ ] ( Lc  Lc) Where Lc, is average length of captured fishes and Lc is length at first capture. Also, Natural (M) mortality was estimated by Pauly’s empirical equation (1984): Ln M=0.0066 -0.279 Ln (L∞) + 0.6543 Ln (K) + 0.4634 Ln (T) According to Total (Z), Natural (M) mortality and bellow relationship, fishery mortality (F) was calculated as: Z= M+F The exploitation ratio (E) was calculated using the equation: F E M F For the morphological study, 10 features (7 morphometric and 3 meristic features) described by Berg (1949), were measured and illustrated in Tables 2 and 3. Before analysis, data were examined for normality by Kolmogorov-Smirnov test. Morphological features were standardized before the analysis and were compared in different ages by oneway analysis of variance (for metric parameters) and the Kruskal-Wallis test (for meristic parameters). Result Age of samples ranged between 1+ and 5+. The 2+ years old fishes were the dominant age group (33.75%) and also 5+ years old with 8.75% had the lowest frequent age groups (Table 1). The specimens had an average age of 2.9 years. Standard length ranged from 63 to 115 mm. Mean values and standard deviations of characteristics are shown in Table 2. Morphometric and meristic characteristics did not vary significantly with increasing age (Table 2). According to length-age relationship, length increased with increasing age logarithmically (Fig. 1, P<0.001) indicating that young specimens grow faster than older ones. Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 145 145 Table 1. Mean value of standard length (±SD), weight (±SD) and condition factor of common Kilka. Age Number Frequency (%) Standard length (mm) Weight (g) Condition factor Growth rate 1+ 16 10 67.4 ± 3.2 3.64± 0.26 1.14 ± 0.08 ------ 2+ 54 33.75 80.2 ± 6 5.37 ± 1.16 1.03 ± 0.1 0.17 3+ 40 25 95.9 ± 2.1 8.65 ± 1.73 0.98 ± 0.18 0.18 4+ 36 22.5 102.1 ± 1.9 9.32 ± 1.16 0.88 ± 0.12 0.06 5+ 14 8.75 109.1 ±1.8 10.95 ± 1.15 0.88 ± 0.12 0.07 Total 160 100 89.3 ± 13.2 7.38 ± 2.64 0.98 ± 0.15 0.48 Table 2. Mean (±SD) of morphometric-meristic characteristics of common Kilka. Character/age 1+(n= 16) 2+(n= 54) 3+(n= 40) 4+(n=36) 5+(n=14) Mean Body depth 15±1.41 18.13±2.67 20.82±2.72 22.21±1.93 23.24±2.82 20.23 5.62±0.75 7.19±1.71 8.10±1.58 8.05±1.02 8.08±1.05 7.71 13±0.82 16±1.83 18.15±1.86 18.83±2.04 19.88±2.18 17.58 Distance between eyes 2.17±0.15 2.81±0.80 3.29±0.76 3.52±0.62 3.43±0.48 3.17 Eyes diameter 3.5±0.27 4.12±0.55 4.51±0.54 4.80±0.38 5.03±0.49 4.45 35.50±1.29 40.98±3.18 46.71±4.61 50.29±1.60 51.88±2.87 45.56 Caudal depth Caudal fin length Head and dorsal fin D Dorsal and caudal fin D* 28±0.82 32.82±3.29 36.62±3.90 39.88±2.52 41.65±1.77 36.17 Dorsal fin rays 14.25±0.50 14.84±0.89 14.80±0.83 14.71±0.86 14.88±0.78 14.79 Pelvic fin rays 14.75±0.50 15.13±2.07 15.09±2.30 14.71±0.81 14.82±0.64 15 Caudal fin rays 28.25±0.96 26.71±3.73 27.30±4.09 27.46±2.08 28.12±1.65 27.24 *D= distance Table 3. Some biological parameters of C. cultriventris were taken from previous studies (Abtahi et al., 2002; Abtahi et al., 2005; Fazli et al., 2006 and Janbaz and Abdolmaleki, 2009) and present study. Parameter Fork length (mm) Body weight (g) Age Dominant ages (year) (year) 2.6 0-5 1 (0-3) b Year Mean S.D Min Max Mean S.D Min Max 1997 92.8 9.92 67.5 112.5 6.24 1.55 3.1 9.5 1998 87.3 12.38 57.5 122.5 4.89 1.77 1.4 10.2 1999 82.5 8.48 47.5 107.5 4.17 1.17 0.8 8 2000 81.5 6.76 57.5 107.5 3.82 0.84 1.5 7.5 2.512 0-5 2 (0-3) 2001 88.3 5.89 67.5 107.5 5.24 0.83 1.7 10.9 2.455 0-5 3 (2-4) 2002 85.12 7.84 52 121 4.446 1.35 1.37 14.02 2.28 1-6 3 (2-4) 2004 84.35 --- 65 105 4.28 --- 1.7 7.19 --- --- --- 2008 93.8 11.8 50 127 7.1 2.1 1.1 16.5 2.77 1-6 4 (4-6) 2010 90.3 13.2 63 111 7.42 2.72 3 13.03 2.581 1-5 2 (2-4) According to Pauly test (P<0.05), weight and length had negative allometric relation (b=2.58), showing that the length increased faster than the weight (Fig. 2). Standard Von-Bertalanffy growth equation was estimated as follow: Lt=123.7 (1-e -0.356(t+1.4)) According to this formula, coefficient growth, infinity length (basically standard length) and age of fish at zero length calculated as 0.3585 per years, 120.71 mm and -1.4 years, respectively. Growth performance index was 1.66. The total mortality (Z), natural (M) and fishing (F) mortality coefficients were 0.9 year, 0.43 and 0.47, 146 Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 Figure 1. The relationship between standard length and age in common Kilka Figure 2. Relationship between standard length and weight, in common Kilka respectively. The exploitation ratio (E) was calculated as 0.52. (2006) suggested that after Mnemiopsis sp invasion in 1998, the Kilka stock migrated to deeper waters because of food competition with Mnemiopsis sp. Migration of common Kilka to deeper waters has resulted in over-exploitation and decrease of C. engrauliformisas as the main species in commercial catch (Fazli et al., 2002). Kilka had negative allometric growth which varied during these years. Variation of the coefficient b depends on species, habitat, sex, age, feeding, season, etc. (Bagenal and Tesch, 1978). Age composition data help us to understand the effect of environment factors on growth parameters and fishery recruitment (Stevensen and Campana, 1992). At the present study five age groups were found. Age structure varied like other parameters described before. The dominant age has increased from 1+ to 4+ since 1999, and decreases to 2+ (because the mean age is 2.9 and the 3+ years old have a high frequency (25%), we can considered it equal 3). A decrease in the mean and maximum length, number of age groups and dominant age in present study, indicate that Kilka population is under pressure and also it can be a sign that other species of Kilka who lived in deeper water may be in risk. At the present study fishing (F) mortality coefficient was 0.47, whereas Janbaz and Abdolmaleki (2009) reported this value as 0.44. Also the exploitation ratio of common Kilka reported as 0.294 – 0.411 and 0.51 by Chilton et al. (1982) and Janbaz and Discussion Among the Clupeonella species, common Kilka (C. cultriventris) has a distinctive distribution depth and lives in pelagic area at depth less than 50 m in the Iranian water. Recent study has shown that Kilka stocks are over-exploited (Karimzadeh et al., 2010). Also, comparison of the caught rates of three Clupeonella species indicates that, cone net is not proper fishing device for Kilka, so it can be exploited by independent catching methods (Abtahi, 2001; Paritskii et al., 2001; Razavi Sayyad, 1993). Some biological parameters of C. cultriventris which were reported in previous studies are showed in Table 3. According to Table 3, similar changes have happened in some parameters such as length, weight compositions and regression coefficient (b) since 1997. These changes show that common Kilka stock has been changed. For example the mean fork length was 92.8 mm in 1997 and it decreased to 81.5 during 1997-2000 (Fazli et al., 2006). After 2000, it increased to 93.8 (in 2008) again. In present study it was 90.3 ± 13.2 mm. This variation can be seen in weight, too. Mean body weight of Kilka is reported 6.24 g in 1997, 3.84 g in 2000 and 7.1 g in 2008. Based on the previous and present studies it seems that Kilka population has become younger during 1997-2000 and then older in 2000-2010. Fazli et al. 147 Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 Abdolmaleki (2009). At the present study, it was 0.51. All of these data confirm that the Kilka population is under pressure (Fazli et al., 2002). The analysis of mean values of characteristics did not reveal significant differences between age groups especially in meristic characteristics because, most of specimens were adult (Kilka matured in 2 years old), so there was not a lot of variation in morphological characteristics. The average of body and caudal depths, caudal fin length, distance between eyes, eyes diameter and caudal fin rays of C. engrauliformis were 19.3±1.33, 6.96±0.7, 3.61±1.24, 5.59±0.88, 5.02±0.72 and 14.64±2.5, respectively (Rahimi Bashar and Alipour, 2009). Except the caudal fin length and distances between eyes which are higher in common Kilka, other parameters are similar to each other. This is maybe explained by species-specific characteristics’. In conclusion, it is important to avoid over- and unmanaged fishing in spawning period of Clupeonella sp to recruit and preserve their stocks. We suggest continuation of Kilka’s biological features to have a good view on status of stocks for better management and conservation. Also we suggest design of special fishing method for common Kilka. Acknowledgment We are grateful to Alireza Kalantari for providing samples from Babolsar commercial catch site, to Masoud Mollaei, expert of fishery laboratory and to fishery Department of Gorgan University of Agricultural Sciences and Natural Resources for his support. References Abtahi B. (2001). A review on biological and fishery resource of Caspian Sea, lecture presented on Caspian Sea framework, oceanology national center, 1: 147-167. Abtahi B., Jelodar T.H., Yousefian M., Fazli H. (2005). Anatomical and histological study of ovary maturity stages of common Kilka delicatula). Pajouhesh and (Cluponella 147 Sazandegi, 63: 47-54. Abtahi B., Jelodar T.H., Fazli H., Yousefian M. (2002). Study on fecundity and some morphological indexes of common Kilka (Clupeonella cultriventris) in Mazandaran province water. Journal of Iranian Marine Science and Technology, 1: 1-9. (in Farsi) Anonymous. (1978). Ecological features of the Caspian Sea (Genus Clupeonella). KaspNIRKH (Caspian Fisheries Research Institute), 15p. Bagenal T.B., Tesch F.W. (1978). Age and growth. In: T.B. Bagenal (Ed.). Methods for assessment of fish production in freshwater. Blackwell Scientific Publication, pp: 165-201. Besharat K., Khatib S. (1993). Determination of Kilka (genus: Clupeonella) fishing area in northern parts of Iran and hydrologic and Hydrobiologic studies on the Caspian Sea. Final Report. Mazandaran Fisheries Research Center. 181 p. Berg L.S. (1949). Freshwater fishes of Iran and adjacent countries. Trudy Zoologicheskogo Instituta Akademii Nauk SSSR, 8: 783-858. Beverton R.J.H., Holt S.J. (1956). A review of methods for estimating mortality rates in exploited fish population, with special reference to sources of bias in catch sampling. Rapp. P. V. Reun. CIEM, 1: 67-83. Chilton D., Richard E., Beamish J. (1982). Age determination methods for fishes studied by the Groundfish program at the Pacific Biological Station. Canadian Special Publication of Fisheries and Aquatic Sciences, 60: 102 p. Erdogan O. (2002). Studies on the age, growth and reproduction characteristics of the Chub, Leuciscus cephalus orientalis (Nodman. 1840) in Karasu River, Turkey. Turk Journal of Veterinary and Animal Science, 26: 983-991. Fatemi S.M.R., Kaymaram F., Parafkandeh Haghighi F., Vosooghee G.H., Taghavi Motlagh S.A. (2009). Validation of back-calculation methods using otolith to determine the length of anchovy Kilka (Clupeonella engrauliformis). Iranian Journal of Fisheries Sciences, 8: 115-126. 148 Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 Fazli H. (1990). Biology of genus Clupeonella in Caspian Sea. Conference of suitable exploitation of the Caspian Sea aquatics. Babolsar, 81-89. Fazli H., Bourani M., Janbaz A., Naderi M., Abo M., Moghim M., Ofi F., Azari A. (2002). Study of Kilka biology and statistics in commercial fishing regions. Final report. Mazandaran Fisheries Research Center, 112 p. Fazli H., Rouhi A. (2002). Probable effect of ctenophore entrance on Kilka species composition, catch and stock in southern Caspian Sea (1997-2001). Iranian Journal of Fisheries Science, 1: 63-72. Fazli H., Sayyad Bourani M., Janbaz A.A. (2004). Big eye Kilka (Clupeonella grimmi) biological characteristics in Iranian commercial fishing during 1997-2001. Iranian Journal of Fisheries Science, 13: 125-138. Fazli H., Sayyad Bourani M., Janbaz A.A. (2005). Common Kilka (Clupeonella cultriventris caspia) biological characteristics and the effects of Mnemiopsis Leidyi in southern part of the Caspian Sea. International Journal of Research in Marketing, 69: 87-96. (in Farsi) Fazli H., Sayyad Bourani M., Janbaz A.A. (2006). The biological characteristics of Clupeonella cultriventris caspia in southern coast and the impacts of Mnemiopsis leidyi invasion on the Caspian ecosystem. Pajouhesh and Sazandegi, 69: 87-96. Fazli H., Zhang C.I., Hay D.E., Lee C.W., Janbaz A.A., Sayyad Bourani M.S. (2007). Population dynamics and stock assessment of common Kilka (Clupeonella cultriventris caspia) in the Caspian Sea. Iranian Journal of Fisheries Science, 7: 4770. Janbaz A., Abdolmaleki SH. (2009). Age, growth and mortality of Clupepnella cultriventris caspia in the coastal Mazandaran. Pajouhesh and Sazandegi, 81: 78-80. Karimzadeh G., Gabrielyan B., Fazli H. (2010). Population dynamics and biological characteristics of Kilka species (Pisces: Clupeidae) in the southeastern coast of the Caspian Sea. Iranian Journal of Fisheries Science, 9: 422-433. Mamedov E.V. (2006). The biology and abundance of Kilka (Clupeonella spp.) along the coast of Azerbaijan, Caspian Sea. Journal of Marine Science, 63: 1665-1673. Naderi M., Fazli H. (1996). Study on reproductive, fecundity and feeding of Clupeonella spp in north costal of Caspian Sea. Iranian Journal of Fisheries Science, 6: 1-6. Parafkandeh Haghighi F. (2009). Population dynamics of Kilka fishes in southern Caspian Sea. PhD thesis in marine biology. Islamic Azad University, Sciences and Researches Branch. Tehran. Paritskii Y.A., Kolosyuk G.G., Mikhin S.P. (2001). On the results of the Caspian Kilka stocks decrease in 2000-2001. The international conference “The questions of the investigation and rational use of marine natural resources”. CaspNIRKH, Astrakhan (Russia), 171-174. Pauly D. (1984). Fish population dynamics in tropical waters: A manual for use with programmable calculators. ICLARM. Manila. Pauly D., Munro J.L. (1984). Once more on the comparison of growth in fish and invertebrates. ICLARM Fish byte. Pourgholam R., Sedov V., Yermalchev V., Besharat K., Fazli H. (1996). Stock assessment of Kilka fishes by hydro acoustic method, 1994-1995. Final report, Mazandaran Fisheries Research Center, 125 p. Rahimi Bashar M.R., Alipour V. (2009). Study on biometric parameters and natural diet of Clupeonella engauliformes in coast of Guilan province. Biological Science Journal of Lahijan University, 3 (2): 25- 35. (in Farsi) Razavi Sayyad B. (1993). Abundance and distribution of Kilka in Iranian waters. Scientific Bulletin of Iran Fisheries, 2: 11-25. (in Farsi) Stevensen D.K., Campana S.E. (1992). Otolith microstructure examination and analysis. Canadian Special Publication of Fisheries and Aquatic Science, 117-126. 149 Kohanestani et al./ Int. J. Aquat. Biol. (2013) 1(4): 143-149 Sayyad Bourani M. (1997). Survey on some biological characteristics of anchovy Kilka (Clupeonella engrauliformis) in Guilan waters. Iranian Journal of Fisheries Science, 6: 59-70. Yaoungs W., Robson O. (1978). Estimation of population number and mortality rates In: T.B. Bagenal (Ed.). Methods for assessment of fish production in freshwater. Blackwell Scientific Publication. pp: 137-164. Yermalchev V., Sedov S.A. (1990). Caspian Sea Kilka fishes stock assessment with hydroacostic method. Murmans, 90 p. 149