Academic Journal of Current Research Vol.5, No.11, 2018; ISSN (2343 – 403X); p –ISSN 3244 - 5621 Impact factor: 5.67 LENGTH-WEIGHT RELATIONSHIP AND CONDITION FACTOR OF SOME FISH SPECIES OF RIVER TUNGA IN AWE, NASARAWA STATE, NIGERIA Abari, M.A*. and Umar, K.A Department of Fisheries Technology, College of Agriculture, Lafia *Correspondence author: [email protected]; [email protected] Abstract: The fishery of river Tunga is well known but little has been studied about it. Length-weight relationship and changes in the condition factor of some fish species from order characiformes, family characidae-Hydrocynus brevis, Alestes dentex, Hydrocynus forskahlii and Brycinus leuciscus were analysed from samples collected between January – December, 2016, Length-weight relationship of the species in this study revealed a negative allometric growth with “b” value below 3, only Alestes dentex had “b” slightly above 2 while others had values below the range of 2 – 4. However, higher condition factors were observed for Brycinus leuciscus compared to the other species in this study. Keywords: Length-weight Relationship, Condition Factor, River Tunga in Awe, Nasarawa State, Nigeria. INTRODUCTION ecological and biological factors such as degree of fitness, gonad Every living organism grows in both length and weight and the development and the suitability of the environment with regard to relationship between them is of both theoretical and practical the feeding condition (MacGregoer, 1959). importance (Sarkar, et al., 2008). Length-weight relationship is The objectives of this study are to compare the length-weight one of the most important estimated biological aspects of fish in relationship and condition factors of four species from order fisheries study (Mendes et al., 2004). However, fishes in the characiformes for family characidae (Hydrocynus brevis, Alestes tropics and some of the tropical water bodies usually experience dentex, Hydrocynus forskehlii and Brycinus leuciscus) of Tunga frequency growth fluctuations due to so many factors. Some of River. the factors includes; environmental changes, availability of food, MATERIALS AND METHODS sex spawning rate etc. To assess the influence of the Collection of Fish Sample and Measurement aforementioned factors, the knowledge of the length-weight Monthly specimens of four species of fish of characidae family relationship is very essential (Kulbichi et al., 1993). Like other from river Tunga were randomly collected between January to morphometric characters, the length-weight relationship can be December, 2016 from fisher folks catch for this study. The four used as character for differentiation of taxonomic units and the fish species namely Hydrocynus brevis, Alestes dentex, relationship changes with various developmental events in life Hydrocynus forskahlii and Brycinus leuciscus. The fishermen such as metamorphosis, growth and onset of maturity (Thomas et used different types of fishing gears (passive and active fishing al., 2011). gears) which include seine nets, traps, gillnets, cast net, hook and The condition factors show the degree of well-being of fish in line and crafts. Each sampling was conducted between the hours their habitant is expressed by coefficient of condition also known of 7.00am to 1.00pm. The specimens were transported to the as length-weight factor. The factor is a measure of various college of Agriculture Lafia, in the fisheries department Academic Journal of Current Research An official Publication of Center for International Research Development Double Blind Peer and Editorial Review International Referred Journal; Globally index Available www.cird.online/AJCR: E-mail: [email protected] 77 Academic Journal of Current Research Vol.5, No.11, 2018; ISSN (2343 – 403X); p –ISSN 3244 - 5621 Impact factor: 5.67 laboratory for laboratory analysis: The specimens were mopped DISCUSSION on filter paper to remove excess water from their body surfaces. Some authors reported that “b” values usually ranges from 2.0 to Their total and standard lengths were then measured using a ruler 4.0 for several fish species (Taiwo and Aransiola, 2001, Offem et to the nearest one tenth of the centimeter. The total length was al., 2009, Riedel et al., 2007, Ikomi and Odum, 1998, Lawal et al. measured as the distance from the snout to the tip of the caudal fin (2010), Al-Baz and Grove (1995) and Ofori-Danson et al., (2002), while the standard length was measured as the distance from the however, Carlander (1969) and Frose (2006) reported that the snout to the caudal peduncle. acceptable range of condition factor as between 2.5 and 3.5. The The body weight was taken on a top loading metler balance to the results obtained indicated that the length weight relationship of nearest 0.1g. only Alestes dentex was within this range while others had a very Length-weight relationship: A scatter plot of log body weight low “b” value. Pauly (1983) reported that a slope greater than 3 against log, total length was made for each species. The regression denotes allometric growth. Abobi (2015) noted that a “b” value of of weight against length was computed from the relationship W = between 2.5 and 3.5 for Brycinus leuciscus, Hydrocynus aLb forskahlii, Labeo coubie, Labeo parvus, Labeo senegalensis and Where W = weight (g), L = Total length (cm), a = regression Schilbe mystus which is higher than the figure reported in this constant and b = allometric coefficient. study. However, differences in the “b” value reported by the The logarithms transformation of the equation gave a regression various authors is due to species variation, strain variation, stock expression: LogW = Loga+blogL (Pauly, 1984). variation, differences in environmental factors, sex variation to Condition factor (K): The condition factor (K) was calculated mention but a few. The trend of result observed in this study for individual species of the family characidae for each month shows that all the species studied had a negative allometric growth using the conventional formula described by Worthington and (”b” value below 3) hence, the population of fish can therefore be Richard 1930, K = Wx100 considered as having homogenous groups with body weights L3 varying indifferently from the cube of total length (L3). Negative Where K = condition factor, W = body weight in grams, L = allometric growth according to Riedel et al. (2007) implies the Standard length of fish (cm). According to Wooton (1992) fish in fish becomes more slender as it increase in weight while positive good condition will have K-value greater than 3. allometric growth implies the fish becomes relatively shorter or Statistical deeper-bodied as it increases in length Norejo (2006) had stated Analysis of variance (ANOVA was used to test for significant that the departure of “b” values from 3 would be due to the difference at 95% confidence limit in data for length, weight and seasonal changes while, Le Cren (1951) reported that the condition factors. Using instat statistical package, the values of a deviation of “b” value from isomeric growth either due to and b can be estimated by regression method of analysis. Linear environmental condition or condition of fish. relationship graph of the different species was plotted using Several authors have reported both isometric and allometric Microsoft excel 2007. growth for various fish species from various fish species from RESULTS different water bodies. Allometric growth patterns for Tilapia Negative growth patterns was obtained for all the fish species species from Umuoseriche Lake had been reported by Kings studied Hydrocynus brevis had a “b” value of -0.19 Alestes dentex (1991). Kings (1996) also reported isometric growth for had “b” value of 2.87, Hydrocynus forskahlii and 1.12 and Pseudotolithus elongatus from Qualboe estuary. Pervin and Brycinus leucinus had 0.12. The length-weight relationship reveal Mortuza (2008) reported isometric growth pattern for Ethmalosa a week correlation between the log of length weight of Alestes fimbriata from cross river estuary in Nigeria. dentex (<0.075); Brycinus leuciscus (R2 = 0.021) and Hydrocynus Ogbe et al. (2008) reported that condition factor (K) reflects brevis (R2 = 0.007) and Hydrocynus forskahlii had a value of R2 through its variations, information of the physiological state of the = 0.300. Average condition factor was higher in Brycinus fish in relation to its environment. Higher condition factors were leuciscus (10.42±0.64) and lowest in Hydrocynus brevis (1.54 ± observed Brycinus leuciscus compared to the other species. 0.15). Alestes dentex and Hydrocynus forskahlii had 1.99± 0.22 Different in condition factors can be attributed to different reasons and 1.65+0.08 respectively as condition factors. which includes: stress, sex, season, food availability and other Academic Journal of Current Research An official Publication of Center for International Research Development Double Blind Peer and Editorial Review International Referred Journal; Globally index Available www.cird.online/AJCR: E-mail: [email protected] 78 Academic Journal of Current Research Vol.5, No.11, 2018; ISSN (2343 – 403X); p –ISSN 3244 - 5621 Impact factor: 5.67 water quality parameters (Khallaf et al., 2003). Saliu (2002) average natural conditions. Bagenal (1978) and Frose (2006) further justified that condition factor is not constant for a species opined that variation in condition factor is significantly due to or population over time as it is influenced by both biotic and biological factors, food availability, temporal and sampling abiotic factors such as feeding regime and state of gonadal factors, as well as health and sex. According to Wade (1992) K development. should be equal to 1, below 2 indicate a low condition, K equal 1 The values of relative condition factor in Shahririar Nazrul et al. is an average conditions generally condition factor greater or (2011) experiment ranged from 0.897 – 1.097 for Genetically equal to one is good. Nutritionally, it is assumed that increase or improved farmed Tilapia (GIFT) and were lower than that higher condition factor reflects improvement in nutritional status recorded in the present study.