~ 419 ~  International Journal of Fisheries and Aquatic Studies 2015; 3(1): 419-422  ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62  (GIF) Impact Factor: 0.352 IJFAS 2015; 3(1): 419-422 © 2015 IJFAS www.fisheriesjournal.com Received: 15-07-2015 Accepted: 16-08-2015 Lydia Jyrwa Department of Fishery Science St. Anthony’s College, Shillong - 793001, Meghalaya, India. R N Bhuyan Department of Fishery Science St. Anthony’s College, Shillong - 793001, Meghalaya, India. R Nath Department of Fishery Science St. Anthony’s College, Shillong - 793001, Meghalaya, India. Correspondence R. N. Bhuyan Head, Department of Fishery Science St. Anthony’s College, Shillong - 793001, Meghalaya, India. Email: rnbhuyan60@gmail.com Length – Weight relationship and condition factor of Neolissochilus hexagonolepis (McClelland) in Meghalaya, India: A comparative study Lydia Jyrwa, R N Bhuyan, R Nath Abstract The Length-Weight Relationship and Condition Factor of Neolissochilus hexagonolepis, collected from three different rivers of Meghalaya were studied. The data was analyzed using the formula, W = aL b . The values of ‘b’ indicate a wide variation of growth pattern of the fish in different rivers of the state. The values of ‘r’ proved to be highly significant. The value of Condition Factor indicates a good well-being of the fish. The result also reveals healthy condition of the habitat. Keywords: Length-weight, Condition factor, hexagonolepis, Growth pattern. 1. Introduction Meghalaya, the important hill state of North-Eastern India lies between 25⁰1΄N and 26⁰5΄N latitude and 92⁰52΄E longitude which is crisscrossed with various rivers of different size and length. However, it has been observed that the population structure of different indigenous fish has been declined in the rivers of the state over the years. One such important fish species is Neolissochilus hexagonolepis. Chocolate Mahseer, N. hexagonolepis locally known as ‘Khasaw’ is an icon in the water bodies of Meghalaya. Besides its importance as food fish and sport fish, it also plays an important role in eco-tourism of the North-Eastern region of the country in general and Meghalaya in particular. Growth of a fish is defined as the change in size with reference to time and weight is expressed as a function of length [1] . Knowledge of Length-Weight Relationship (LWR) is of prime importance in fishery biology as it serves several practical purposes. Firstly, it provides a mathematical relationship between the two variables i.e. length and weight of a particular species of fish, so that the unknown variable can be easily calculated from the known variable. The values are important for estimation of number of fish landed at a particular time and comparison of fish species caught from various places at similar or different time [2] . It also allow to estimate the productivity and biomass of a fish population [3] determining the condition factor of fish making a morphological comparison between species and populations. Also, we can get information about the type of fish growth (whether isometric or allometric) by means of LWR [4] . Secondly, a published report on LWR is important for the studies of biology, population and management of species and their fisheries [4, 5] . Besides, it provides information on growth, gonadal development and general condition of the fish. Therefore, it is useful for comparison of body forms as general well-being of different populations of particular species [4] . The LWR in fish is significantly important in terms of fishery ecology and stock management [6] and essential for stabilizing taxonomic characters of the species [7] . Finally, the LWR, is a wide application in delineating the growth patterns during their developmental pathways, in measuring the yield of fish from water masses, etc. [8] The Condition Factor (K) is used in order to compare the ‘condition’, ‘fatness’ or well-being of fish [9] and it is based on the hypothesis that heavier fish of a given length are in better condition than lighter fish of same length from the same population [10] . It is universal that growth of fishes or any other animal increases with the increase in body weight. Thus, it can be said that length and weight are co-related [11] . The LWR parameters and Condition factor have been found very useful to evaluate the well-being of populations, their biology for scientific management of fisheries in stock assessment [12] . It is also important to note that the