جستجوی مقالات مرتبط با کلیدواژه "weight relationship" در نشریات گروه "زیست شناسی"

The age and growth parameters of the brond-snout, Chondrostoma regium in Beheshtabad River of Chaharmahal & Bakhtiari Province were investigated during April 2013 to April 2014. The males ranged between 8.04-22.10cm and 5.20-105.00g. The females ranged between 7.84-23.15cm and 8.70-155.00g. Males were categorized in age classes 1+5 and females in age classes 1+6. The age class 3 was the dominant one in the whole samples. The length-weight relationship for males, females and all individuals was as W=0.0089L3.045 (r2=0.95), W=0.0082L3.109 (r2=0.85) and W=0.0107L3.000 (r2=0.92), respectively, indicating a positive allometric growth pattern for the females and an isometric growth for the males and all fish.
The age-length and age-weight relationships in males and females were estimated as Lt=26.23[1-e-0.267(t.483)], Wt=160.77[1-e-0.267(t.483)]3.045 and Lt=31.89[1-e-0.148(t.067)], Wt=266.11[1-e-0.148(t.067)]3.109, respectively. The growth performance index (Ф') value was 3.84 in males and 2.18 in females, indicating a faster growth rate in males. The mean condition factor was 1.02±0.01 for males and 1.14±0.02 for females. The relative length of gut was 1.18±0.05 for all fish, indicating a herbivorous habit for this fish. The highest mean feeding intensity of males was in July and the lowest in March and April. In the female, the highest was in January and the lowest in June. The highest mean value of Gut vacuity index of males and females was in the spring and the lowest in summer. About 55% of the studied stomachs were full. The highest number of empty stomachs was in May (80%) and the lowest in July (32%). Based on the mean Gut vacuity index (48%), this fish is considered a medium feeding fish (40

The objectives of this study were to determine the age, growth, mortality and exploitation of a commercially important fish of northeastern Mediterranean Sea, Mullus barbatus from the Karatas coast of Iskenderun Bay during September 2002 and April 2003. A total of 212 specimens of red mullet were collected by monthly sampling using traditional bottom trawl net by commercial vessel (Coskun Reis, 22m length and 285HP) from 3 stations in three depth contours in ≤20m, 20-50m and 50-100m, respectively. The age of M. barbatus specimens was estimated by examining sagittal otoliths and it found that the age composition varied from I to V age classes. The mean total length and total weight values was calculated as 10.07±1.83cm and 12.04±8.22g, respectively and the calculated length-weight relationship was W=0.0072*L3.1618. The von Bertalanffy growth parameters were L¥= 21.98cm, k= 0.194 year-1 and to= -1.168 year. The instantaneous rate of total mortality (Z) was 1.39, the natural mortality (M) was 0.45 and the fishing mortality (F) was estimated to be 0.93. The exploitation rate (E) was calculated as 0.67 using value of M and F. As a result of the analysis, the population of M. barbatus from the Karatas coast of Iskenderun Bay was exploited over the optimum level because of overfishing pressure.