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Growth, sex ratio and age of 188 specimens of Tench, Tinca tinca, from Anzali wetland were recorded during Nov. 2013 to June 2014. The age range of fish was 0⁺ to 6⁺ years. Male to female sex ratio was 1:1.7 that differed significantly (P<0.05). Maximum total length (TL) and weight (W) was 40.7 cm and 1000g, respectively. The b value of the length-weight relationship was 2.70 that showed negative allometric growth (p<0.05). The growth performance index (ϕ) was calculated as 2.61. The estimated von Bertalanffy growth parameters were (L_∞= 47.48 cm, k= 0.18 yr^- and t₀= -1.07 yr). T_maxwas calculated 16.41 years. Also infinity weight (W_∞) was estimated as 1261.43 g. The present investigation provides basic information about population structure of Tench (T. tinca) in Anzali wetland.

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Ditylenchus azarbaijanensis n. sp. is described and illustrated based upon morphological and morphometric characters. The new species is mainly characterized by having six lines in the lateral field, rudimentary postuterine sac (PUS) ca. 0.2 vulval body width long, anteriorly inclined vagina and conical female tail with a pointed terminus, 48-70 µm long (c = 15-21, cʹ = 2.4-3.7). It is further characterized by having fine stylet 7.5-10.0 µm long with small knobs, small pyriform pharyngeal bulb offset from the intestine, and males with 26.5-31.0 µm long spicules. By having a rudimentary PUS, the new species is morphologically compared with three closely related species, namely Ditylenchus apus, D. deiridus and D. khani. Moreover, morphological differences of the new species with eight similar species of the genus, namely D. arachis, D. convallarie, D. dauniae, D. medicaginis, D. silvaticus, D. tenuidens, D. valveus, and D. virtudesae are presented. The status of the rudimentary or absent PUS of D. deiridus and the new species is also discussed.