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In Ekiti State, southwest Nigeria, Oreochromis niloticus is significant to live. This investigation was conducted to improve its sustainable management and access the length-weight relationship and condition factor of O. niloticus across important reservoirs in Ekiti State from November 2017 to October 2019. Collected specimens were weighed to the nearest gram, while the entire lengths were measured to the closest centimetre. Log-transformed regression was used to determine the fish's growth pattern in the reservoirs. The gradient comparison was done using the T-test. The length and weight of the species in the reservoirs showed a significant association. All length-weight relationships had r2 values greater than 0.8150 and were significant at P < 0.05. In the length-weight relationship of O. niloticus, the values of the exponent b in Egbe, Ero, and Ureje reservoirs varied from 2.45 to 2.87, 3.02 to 3.20, and 2.45 to 2.82, respectively. The results of regression coefficient b obtained showed that in the combined season, male, female and combined sexes from the Ero reservoir had isometric growth patterns with growth exponent b values of 3.18, 3.20 and 3.19 respectively that were not statistically different from 3. These results contradicted the negative allometric growth pattern in the Egbe and Ureje reservoirs. The condition factor during the dry season ranged from 1.93-2.05, 2.05-2.11, and 1.93-2.03 for fish in Egbe, Ero, and Ureje reservoirs, respectively while in the rainy season, it ranged from 2.00-2.02; 2.08-2.09 and 1.96-2.01 respectively. The fish species studied in the reservoirs lived aboveaverage life and thus indicate that the prevailing ecological conditions in the reservoirs were not beyond the forbearance range for the fish species since their condition factors were within the range considered adequate for freshwater fishes in tropical waters. [ABSTRACT FROM AUTHOR]

Information on the length-weight relationship (LWR) and condition factor (K) of the common smooth-hound shark, Mustelus mustelus collected from fish landing sites located in the coastal areas of Lagos and Ondo States, Nigeria were provided in this study. The sharks were collected from March 2018 to September 2021. In total, 1,018 sharks were measured to the nearest centimeter with a tape measure for their total length while total weight was measured to the nearest gram on a digital balance. The linear regression equation for males, females and combined sexes using log-transformed length-weight relationship revealed a positive allometric growth (b>3) for the females and combined sexes while the males showed negative allometric growth reflecting a comparatively slower growth rate in total weight than in total length throughout the species ontogeny. The analysis of variance indicated a significant difference (P< 0.05) in the length and weight of the female M. mustelus sharks in both sampling locations. The newborn (TL < 50cm), medium (90cm=TL<110cm) and large (TL=110) size classes recorded a mean condition factor value of 0.4 while the young (50cm=TL<70cm) and small (70cm=TL<90cm) size classes had mean condition factor value of 0.3. The lowest K was recorded in October 2018; (0.33) while the highest K value was in January 2019; (0.43). The information obtained from this study would contribute greatly to the efforts to enrich the database on shark fisheries in Nigeria to achieve a better management of this critical species. [ABSTRACT FROM AUTHOR]

The black-chinned tilapia (Sarotherodon melanotheron) is a member of the cichlid family, which can be cultured to complement the output from a predominantly catfish aquaculture industry in Nigeria. In order to achieve this objective, it is important to study the bio-ecology of the fish to ascertain the exploitation status and the potential for culture. Fish were collected monthly from February to November 2018 from three sampling sites (Topo, Akarakumo and Ajido) in Badagry Creek, Lagos, Nigeria using gears like cast net, gill nets and traps. The samples were analysed for length-weight relationship, population parameters and feeding preference. The population dynamics of the stock was assessed by the Von Bertalanffy growth model (VBGM) using Electronic Length Frequency Analysis. The parameters of VBGM; asymptomatic length (L∞) and growth coefficient (K) were 20.46 cm and 0.62 year−1, respectively. The growth performance index (Ǿ) was 2.41 and the potential longevity (tmax) was 4.84 years. The total, natural and fishing mortalities were 1.06, 0.68 and 0.38 year−1, respectively. The exploitation rate was estimated as 0.36. The length at first maturity (L50) was 13.79 cm and the length at first capture (Lc) was 12.27 cm. E0.1, E0.5 and Emax are 0.60, 0.38 and 0.70, respectively. The dominant food items in the gut of the fish belong to the algae phylum, Chlorophyta. The study showed that S. melanotheron from Badagry Creek are planktivores and the exploitation rate of the fish is currently close to optimum and should be sustained at this level to prevent overexploitation. [ABSTRACT FROM AUTHOR]

Length-frequency distributions, length-weight relationships, length-length relationships and condition factors (Fulton's KF, allometric KA, and relative KR) of Arius gigas in the Obuama Creek in Rivers State, Nigeria were investigated. 217 samples were collected from artisanal fishermen fishing on the Obuama Creek from March to September 2019. The parameter b of the length-weight relationship was 2.52 indicating negative allometric growth. The KF ranged from 0.51 to 2.03 with a mean value of 0.85 ± 0 while the overall low values of KR and KA in this study are generally a characteristic of fish in poor health. This study provides basic information on some of the biological features of A. gigas which should be useful for facilitating management strategies and regulations of the stocks. [ABSTRACT FROM AUTHOR]

The body characteristics and yield indices of Clarias gariepinus, Bagrus bajad, Synodontis nigrita, Labeo senegalensis and Mormyrus rume from lower Benue River in Nigeria were determined in this study using 60 samples each for the fish species. Length, weight and fillet correlations were also determined during the study. Results obtained showed that M. rume, L. senegalensis and C. gariepinus had the highest percentage of edible parts (= 55%) compared to the other species (= 39%). Concerning correlations of the fillet with the morphological variables, results obtained suggest that fillet yield is independent of fish size (except for C. gariepinus which was positively correlated). Also, only samples of L. senegalensis showed isometric growth pattern; the other fish species had either positive (C. gariepinus and B. bajad) or negative (S. nigrita and M. rume) allometric growth. While the difference in fillet yield and body characteristics was attributed to the structural anatomy and other biological dynamics of the fishes, this study could not establish a connection between fillet yield and the length-weight relationship. It was concluded that M. rume, L. senegalensis and C. gariepinus would be better export products because of their higher fillet yields. [ABSTRACT FROM AUTHOR]

Length-frequency distribution, length-weight relationship and condition factor of sompat grunt Pomadasys jubelini off the Lagos coast, Nigeria were investigated in order to study the growth pattern of P. jubelini. A total of four hundred and fifty specimens of P. jubelini were used for this study with body lengths ranging from 13.9-26.6cm (total length) and 11.2-22. lcm (standard length). The body weight ranged from 26.8g to 175.1 g. The length-frequency distribution revealed high abundance of P. jubelini in the 21.0-21.9cm (total length) size group which accounted for 17.8% of the total specimens examined. The length-frequency distribution showed a poly-modal size distribution. Length-weight relationship was determined by the regression equation Log W = -1.5325 + 2.8177 Log L (n= 450, r²= 0.69, p < 0.05). P. jubelini showed negative allometric growth (b = 2.8177) which indicated proportionate growth was more in body length than in body weight. The mean condition factor was significantly higher for males (1.92 ± 0.02) as compared to females (1.75 ± 0.03) (p < 0.05). Results of this study are important and relevant for the stock assessment and fishery management of P. jubelini in the Lagos coast. [ABSTRACT FROM AUTHOR]

Length-weight relationship (LWR), condition factor (K) and stomach content of three cichlid fishes (Hemichromis bimaculatus, Sarotherodon melanotheron, and Chromidotilapia guentheri) were calculated at Eleiyele reservoir, Nigeria, Africa. The fish were collected monthly from fishermen during the dry season (January-March 2001) and the rainy season (April, May, June 2001). Gill nets of mesh sizes 50-55 mm were used. The LWR had a significant correlation for the three species and the growth exponent (b) for H. bimaculatus indicates a negative allometric growth (S. melanotheron and C. guentheri had isometric growth). Condition factor values were higher than one in the three species, and varied with size and season. Stomach contents revealed that the three species are omnivorous and that diet composition varies seasonally. [ABSTRACT FROM AUTHOR]