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| dc.contributor.author | Nigussie Arega | |
| dc.date.accessioned | 2022-01-12T12:16:07Z | |
| dc.date.available | 2022-01-12T12:16:07Z | |
| dc.date.issued | 22-01-12 | |
| dc.identifier.uri | http://ir.bdu.edu.et/handle/123456789/12932 | |
| dc.description.sponsorship | The migratory Labeobarbus intermedius was a least concern fish species. The aim of this study was to assess life history traits of this least concern fish species to assist its future conservation. Life history traits of L. intermedius were described by examining whole asteriscus otoliths from 727 specimens (400 females, 308 males and 19 unidentified) collected monthly between June 2016 to May 2017 in Lake Tana using gillnets of various stretched mesh sizes. Otolith were prepared by using whole otoliths submerged in water and placed in glycerol to take the image. Length-weight relationship was fitted using a power equation. The reproducibility and uncertainty of the growth zones counts between readers were computed by means of coefficient of variation (CV), average percentage error (APE) and percentage of agreement (PA). Edge analysis (EA) and marginal increment analysis (MIA) were also used to validate the rate of growth zone deposition on otolith. Akaike’s information criterion (AIC) and Akaike’s weight (AICwt) were used to select the best fit growth model. The relationships between total weight (W) and fork length (FL) were curvilinear and not significantly different between sexes (TW = 2.72 x 10-4 FL 2.86(n = 727, R2=0.94, P = 0.36)). Sex ratio (1.3:1) shows that females were predominant over males. The size of L. intermedius individuals ranged from 120-495mm fork length. The majority of the specimens (68%) were within the length group of 158–271 mm. From the three readers, reader1 Vs. reader 2 had low CV and APE and relatively high PA value (7.4%, 5.2% and 64%, respectively). Edge analysis (EA) and Marginal increment analysis (MIA) showed that a single growth zone is formed each year. A marginal increment ratio analysis indicated that the translucent zone was formed from December to January. The maximum ages recorded were 10 and 15 years for male and female, respectively. The logistic growth model had the best fit to age-at-length data. The growth parameter (L∞, K and to) value in the present study was 412 mm, 0.30 and 4.3 yr-1 for males and 483 mm, 0.29 and 4.95 yr-1 for females, respectively. The highest natural mortality was estimated based on maximum observed Age (tmax) (0.4 yr-1 for females and 0.6 yr-1 for males). The estimated life history traits, which are important input parameters in further stock assessment evaluation might help fisheries managers to optimize future conservation strategies. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | FISHERIES AND AGRICULTURE | en_US |
| dc.title | LIFE HISTORY TRAITS OF Labeobarbus intermedius IN LAKE TANA, ETHIOPIA | en_US |
| dc.type | Thesis | en_US |
