Food and Feeding Habits of the Common Carp (Cyprinus carpio L. 1758) (Pisces: Cyprinidae) in Lake Koka, Ethiopia

Feeding habits of Cyprinus carpio was studied in Lake Koka, Ethiopia, in April and May (dry months) and July and August (wet months), 2011. The objective of the study was to identify the diet composition, seasonal variation in diet and ontogenetic dietary shift. Gut contents of435 fish were analyzed using frequency of occurrence and volumetric analysis. In frequency of occurrence method the number of gut samples was expressed as a percentage of all non-empty stomachs examined while in volumetric method the volume of each food category was expressed as a percentage of the total volume of the gut contents. Detritus, insects and macrophytes were the dominant food categories occurring in 97.0%, 85.2% and 53.3% of the guts and comprising 39.8%, 36.4% and 12.4% of the total volume of food items, respectively. The remaining food categories were of low importance in the diet. The frequency of occurrence and volumetric contributions of the different food categories of C. carpio significantly varied (U-test, p<0.05) during the dry and wet seasons. During the dry season, insects and detritus were important food categories, occurring in 94.4% and 98.6 of the guts and comprising 42.3% and 36.1% of the total volume of food, respectively. During the wet season, detritus was the most important food category. It occurred in 93.9% of the guts and accounted for 48.8% of the total volume of food. Insects and macrophytes were also important during the wet season, occurring in 68.2% and 74.3% of the guts and comprising 23.6% and 22.6% of the total volume of food, respectively. The contributions of animal origin food categories were important in the diet of juveniles whereas food of plant origin were more important in the diet of adults. However, there were no significant variations in the diet of individuals in the different size classes. Based on the results, it was concluded that C. carpio was omnivorous in its feeding habits in Lake Koka with considerable seasonal variation but insignificant onto genetic change in its diet.Keywords: Cyprinuscarpio, Lake Koka, Seasonal and Ontogenetic Variation in Diet, Ethiopia

A four-season prospective study of muscle strain reoccurrences in a professional football club

The aim of this investigation was to characterise muscle strain reinjuries and examine their impact on playing resources in a professional football club. Muscle strains and reoccurrences were prospectively diagnosed over four seasons in first-team players (n = 46). Altogether, 188 muscle strains were diagnosed with 44 (23.4%) of these classed as reinjuries, leading to an incidence of 1.32 strain reoccurrences per 1,000 hours exposure (95% Confidence Interval [CI], 0.93–1.71). The incidence of recurrent strains was higher in match-play compared with training (4.51, 95% CI, 2.30–6.72 vs 0.94, 95% CI, 0.59–1.29). Altogether, 50.0% of players sustained at least 1 reoccurrence of a muscle strain, leading to approximately 3 days lost and 0.4 matches missed per player per season. The incidence of recurrent strains was highest in centre-forwards (2.15, 95% CI, 1.06–3.24), peaked in May (3.78, 95% CI, 0.47–7.09), and mostly affected the hamstrings (38.6% of all reoccurrences). Mean layoff for nonreoccurrences and recurrences was similar: ∼7.5 days. These results provide greater insight into the extent of the problem of recurrent muscle strains in professional football

Assessment of Skeletal Muscle Contractile Properties by Radial Displacement: The Case for Tensiomyography

Skeletal muscle operates as a near-constant volume system; as such muscle shortening during contraction is transversely linked to radial deformation. Therefore, to assess contractile properties of skeletal muscle, radial displacement can be evoked and measured. Mechanomyography measures muscle radial displacement and during the last 20 years, tensiomyography has become the most commonly used and widely reported technique among the various methodologies of mechanomyography. Tensiomyography has been demonstrated to reliably measure peak radial displacement during evoked muscle twitch, as well as muscle twitch speed. A number of parameters can be extracted from the tensiomyography displacement/time curve and the most commonly used and reliable appear to be peak radial displacement and contraction time. The latter has been described as a valid non-invasive means of characterising skeletal muscle, based on fibre-type composition. Over recent years, applications of tensiomyography measurement within sport and exercise have appeared, with applications relating to injury, recovery and performance. Within the present review, we evaluate the perceived strengths and weaknesses of tensiomyography with regard to its efficacy within applied sports medicine settings. We also highlight future tensiomyography areas that require further investigation. Therefore, the purpose of this review is to critically examine the existing evidence surrounding tensiomyography as a tool within the field of sports medicine

Food and feeding habits of the straightfin barb Barbus paludinosus (Peters, 1852) (Pisces: Cyprinidae) in Lake Ziway, Ethiopia

The feeding habits of the straightfin barb Barbus paludinosus was studied in Lake Ziway, Ethiopia, from 504 gut samples collected from April to May (dry months) and July to August (wet months) of the year 2011. Gut contents were analyzed using the frequency of occurrence and volumetric analysis methods. Insects and detritus were the dominant food items and they occurred in 86.3% and 93.5%, and constituted 47.3% and 38.0%, of the total volume of food items, respectively. Macrophytes, phytoplankton, zooplankton and ostracods occurred in 36.1%, 40.3%, 32.7% and 15.5% of fish guts and volumetrically they constituted 4.8%, 4.7%, 3.9% and 1.3% of the food items, respectively. Insects, detritus and zooplankton were important food categories in the dry season while detritus, insects and phytoplankton dominated in the wet season. Insects were the dominant food items in all size classes followed by detritus. The proportion of macrophytes increased with size of fish while the importance of detritus and zooplankton declined with fish size. Based on these results, it was concluded that B. paludinosus in Lake Ziway has an omnivorous habit. Keywords: B. paludinosus, Diet composition, Fish feeding habit, Lake Ziway, Ontogenetic diet shifts

Feeding habits of the catfish Synodontis schall (Bloch & Schneider) (Pisces: Mochokidae) with emphasis on its scale-eating habits in Lake Chamo, Ethiopia

Synodontis schall (Bloch & Schneider) is an abundant fish in Lake Chamo, but its feeding ecology is not well-known to guide its management. Diet composition and ontogenetic diet shift were investigated from stomach contents of 545 fish from August 1998 to February 2000. Volumetrically, the dominant food items were zooplankton, fish scales and macrophytes. Zooplankton occurred in 83.3% of the stomachs and accounted for 26.5% of the total volume. Fish scales occurred in 35.0% of the stomachs and accounted for 30.6% of the total volume of food. Macrophytes occurred in 9.8% of the stomachs and contributed 19.4% of the total volume of food eaten. Insects occurred in 37.3% of the stomachs and contributed 8.3% of the total volume of food eaten. Fish fry occurred in 13.7% of the stomachs and constituted 10.9% of the total volume of food consumed. Diatoms, zooplankton and insects constituted 89.8% of the volume of food eaten by juveniles, but their importance declined with the size of fish. Importance of fish scales increased with size of fish. From these results, it is evident that zooplankton and insects were the most important food items of juveniles while fish scales, fish fry and macrophytes were the most important food items of adults. The information obtained from this study allows us to determine the effect Synodontis has on other organisms through competition and predation. This knowledge can be used in management of Synodontis fisheries by determining the prey type of the species and how the changing biological and physical conditions in the lake affect them.Key words/phrases: Ethiopia, Feeding, Lake Chamo, Synodontis schall