Length-weight relationship and relative condition factor of some hill stream fishes, India

Knowledge of some quantitative aspects such as length-weight relationship is important in fishery science. During present study four fish species were studied from different streams for length-weight relationship and relative condition factor. The regression coefficient (b) was unique for each species in each stream. It was lower in the streams of smaller dimensions and higher in the streams of larger dimension; P. conchonius low in Suswa Mothoronwala, high in Asan Chakmansa, B. bendelisis low in Henwal at Khadi, high in Asan at Dharmawala, and T. putitora low in Shyampur Khadri Nala, high in Khoh at Kotdwar. However, low and high ‘b’ values for S. rupecola could not be explained on similar grounds because the dimensions of the brooks did not differ. The b value helped to determine allometric or isometric growth in these fishes. B. bendelisis shows isometric growth in all streams while P. conchonius, T. putitora and S. rupecola shows both isometric and allometric growth in different streams. In most of the cases the relationship followed cube law. The Kn values ranged from 0.790 to 1.447 for B. bendelisis, 0.713 to 1.627 for T. putitora, 0.366 to 1.868 for P. conchonius and 0.211 to 1.754 for S. rupecola. The highest variation in the Kn value was observed for P. conchonius at SuM and S. rupecola at Dhundseer Teen Chhade which may be attributed to varied environmental conditions of the streams inhabited by them.