Using the back calculation to study of the age and growth of Caspian trout (Salmo Caspius)

The present study was aimed at studying the growth and age structure in the Caspian trout (Salmo Caspius). The back calculation and biometrical parameters including body length and weight, and age were, respectively determined in 43 and 101 individuals captured from Cheshmehkileh River, Tonekabon, Iran. The fish were with minimum and maximum age of 4 and 7 years, respectively, while the 5 year-old fish were the most frequent. The mean length and weight of cathead individuals were measured to be 69.2±6.2 cm and 3323±677 g, respectively. According to the back calculation method in 2014, the mean length of 1-, 2- and 3-year-old fish were 18.98±3.5, 30.5±7.24 and 41.7±9.1 cm, respectively that were below maturity age, and thus did migrate to the coastal area for spawning. The males showed larger size, however greater prevalence and frequency were occurred in females. Growth parameters including growth coefficient (K) and L∞ were measured to be 0.18, 104 cm, respectively, and growth performance index (Ø’) was calculated 3.289 indicating an allometric negative growth. Calculated L∞ and K were in an acceptable range. Here, we provide back-calculated size-at-age estimates based on otoliths from individuals belonging to native fish from the Cheshmekileh River while male possessed larger size however the greater prevalence and frequency occurred in female fish.

Using the back calculation to study of the age and growth of Caspian trout (Salmo Caspius) Keywords:

Back calculation , Caspian trout (Salmo caspius) , Caspian Sea , Growth , Age