The present morphometric analysis represented the actual scientific length-weight relationships (LWRs) for commercially important five fish species namely Salmostoma bacaila, Setipinna phasa, Polynemus paradiseus, Silonia silondia, Chelon parsia from Rupnarayan River in South West Bengal, India. Samples were collected from different fishing centre at Rupnarayan River basin on regular mode of quarterly interval from the year August 2016 to January 2018. LWRs parameters likewise intercept (a ), slope (b) from the formula W= a TLb have been calculated out of total 1190 individual sample under five families. Thus, the LWR parameter b value ranged from 2.89 to 3.13 whereas regression coefficients (r2) range confined within 0.95% to 0.98%. Hence, the current assessment may help concerned to researchers and policy makers for sustainable management and conservation aspects of these commercial fishes available in Rupnarayan River, West Bengal, India.

Six different supplementary feeds (Mostly agricultural wastes) have been tested to assess the effectiveness on growth of Labeo rohita (Ham.). The experiment was continued for 100 days in cemented tanks. The daily average weight increment for individual (g/fish/day) fish was 0.762 with rice bran + ground nut oild cake + poultry droppings (1:2:1); 0.478 with goat gut content; 0.453 with poultry droppings + its gut wall (1:1); 0.391 with rice bran + mustard oil cake (1:1); 0.310 with boiled (spoiled) egg + wheat bran (1:2) and 0.108 in control. The merits and demerits of different feeds have been discussed in this paper.

Studies on energy budget in relation to various dietary conditions were made in an air breathing fish, Channa striatus (BL.). The feeds used were-poultry gut content + goat liver (Group A), blood clot or meal (B), Poultary droppings + Rice bran (C) and goat gut content (Group D). Food efficiency (%) ranged from 11.50 -48.4%. Daily individual growth increment (g/fish/day) ranged from 0.117 (Group A) to 0.501 (Group D). The details have been discussed in this paper.

The present paper deals with the statistical relationship between body weight (g) Vs. total gill diffusing capacity per unit time (mlOiminImmHg) and per unit body weight (m102/min/mm/kg) in a hill stream fish, Garra gotyla (Gray). In this fish total diffusing capacity per unit time (m102/min/mm/Hg) showed increasing trend with the increase in body with a slope (b value) of 0.872 while diffusing capacity per unit body weight (m102/mm/mmHg/kg) decrease with the increase in body weight with a slope (b value) of -0.130. The correlation coefficient (r value) were very high. The details have been discussed in this paper.

Studies on sublethal concentration of Carbofuran (a carbamate pesticde) and Ekalux EC 25 (an organophosphate pesticide) on changes in some haemato-biochemical parameters in an air breathing fish, Channa striatus (Bloch) were made. In control group of fishes, the values of blood glucose, plasma protein and blood urea were 68.92±1.23; 4.92±0.36 and 29.32±1.3 mg/100m1 of blood respectively. The exposure of fishes to sublethal concentrations of both the pesticides for 96 hrs caused significant increase in blood glucose and blood urea but significant decrease in plasma protein. The reason for such changes has been discussed in this paper

Studies on relative energy budget in different weight groups in a fresh water siluroid fish, Mystus cavasius (Ham.) has been made at water temperature 30.0±1.0°C. The total energy available in feed (C)/day/fish ranged from 2192.4 Joules (in 12.2g fish) to a value of 26989.2J (in 102.0g fish). The percent energy value ranged from 12.3-13.6, 7 (fixed), 35.2-36.8, 36.0-43.3 and 0.6-8.2% respectively in faeces (F), Urine formation (U), growth (P), respiratory metabolism (R) and miscellaneous activities (M.A.). The details have been discussed in this paper.

Studies on the effect of Nuvan (Dichlorvos 76% EC-an organophosphate pesticide) on changes in certain haematological values were made in a fresh water air breathing climbing perch, Anabas testudineus (Bloch). The control level of different haematological values in the blood of this fish such as- RBC counts, Hb content, PCV, MCH, MCV, MCHC, ESR, CT and leucocyte (WBC) counts were respectively 3.46±0.07 (million/mm3), 11.7±0.12g%, 46.8±2.43%, 32.94pg, 135.26pm3, 24.675%, 2.9mm/h, 24.35±0.023 and 4.6±0.67 104/mm3. The acute exposure (96 hrs) of Nuvan at sublethal dose (15 mg/I) caused reduction in RBC counts, Hb content, PCV, MCH, MCV, ESR and WBC counts and an increase in the values of MCHC CT, small lymphocytes and Neutrophil % as compared to control. The reason for such changes has been discussed in this paper.

Mastacembelus armatus (Lac) has bimodal gas exchange mechanism as the fish uses both the gills and skin to obtain 02 from water. The skin can obtain 02 both from water as well as air. 02 consumption in this mud eel have been determined by the method as followed by Kumar and Ahsan (2018) at the water temperature 20.0±1.0°C (winter) and 30.0±1.0°C (Summer). The statistical relationship between 02 consumption (V02) vs. body weight during winter (20.0±1.0°C) and summer (30.0±1.0°C) months are represented by the equation :- V02 (ml/hr) = 0.1397.14/97286 and V02 (ml/hr) = 0.219514r1° respectively. The details have been discussed in this paper in the light of thermal compensatory metabolic regulation in this fish.