To study length-weight relationship (LWR) and length-length relationships (LLRs) of farmed Catla catla, thirty fish specimens were collected from a fish farm located at Muzaffargarh, Pakistan during January, 2019. Total length (TL), standard length (SL), fork length (FL) and body weight was taken of each fish specimen. Mean TL and body weight (W) of studied fish specimens of C. catla was found 49.14±1.58 cm and 1775.29±191.18 g, respectively. Results of regression analyses revealed highly significant (P < 0.001) correlation for LWR and LLRs in farmed C. catla. Value of exponent b was found 3.23 in LWR of farmed C. catla indicating positive allometric pattern of growth in C. catla. While, in LLRs, b-value was observed 1.00 or close to 1.00, indicating isometric pattern of growth in SL and FL with an increase in TL for the studied fish species. Mean condition factor value was found 1.49±0.04 in the present work. Results of this work will be useful for fishery biologists and fisheries management.

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I n flourishing fish industry, one of the major impediment is the cost of fish feed ingredients of the total production budget (Cheikyula et al., 2020) because fish meal is the preferred gold standard component of fish feed but highly expensive and limited in supply (Radhakrishnan et al., 2016). Although, now it is considered both environmentally and ecologically unsustainable and requires to find alternative proteins due to economic pressure on the aquaculture industry (Turchini et al., 2019). For successful aquaculture, there is a need to replace fish meal for the preparation of fish feeds, particularly for omnivorous fish species. Plant based protein sources can cope the need of the time due to increasing fish culture as population is increasing day by day (Daniel, 2018; Zettle et al., 2019). Alternative plant protein sources like pulses, grains and oilseeds are widely used for economic fish feed preparations (Abdel-Warith et al., 2019).

DNA barcoding is a rapid, precise, and effective way of species identification. A short and standard target gene marker is used to create sequence profile of identified species. Specific tag or marker is used, which is derived from mitochondrial COI for identification. Effectiveness of this method axes the degree of divergence among species. Identification is necessary for their representation. In the present work, Catla catla was used to study by using Cytochrome C Oxidase 1.The genetic distances were computed, and Neighbor Joining tree was constructed based on the Kimura 2 Parameter method. GenBank and BOLD revealed definitive identity matches. Conspecific and congeneric K2P nucleotide divergence was estimated. Evolutionary tree was analyzed clearly by relating their species to phylogenetic tree, as same as species were bunched under same tree node, while species were differently clustered under distinct nodes. These findings conclude that the gene sequence may serve as a milestone for identification and phylogenetic history of related species at molecular level.

Cirrhinus mrigala (Family Cyprinidae) have vast presence in different studied rivers of Pakistan. Present study was designed to formulate the genetic diversity of desired sites in Cirrhinus mrigala populations using nine Random amplified polymorphic DNA markers. Total hundred individuals were used to conduct this study and were collected from three distinct rivers (River Indus, Chenab and Ravi) with four specified sites with wild of Pakistan were used to study. A random Amplified Polymorphic DNA primer analyzes various bands of polymorphic loci. Mean genetic diversity within and between populations found 81.53% and 2.27% respectively by using analysis of molecular variance. Fixation index was found variably and Pairwise Fst analysis showed significant difference between different sites of studied populations. Genetic divergence information would mark essential in order to improve genetic programming its management and conservation of natural inhabitation. In order to quantify the study of population divergence by using these molecular markers is an efficient way to pin point the genetic diversity within and among population.