Biological parameters and current status of European eel (Anguilla anguilla Linnaeus, 1758) from Asi River, Northeastern Mediterranean region, Turkey

The biological characteristics of eels from the Asi River, Turkey, were assessed between December 2017 and November 2018. Eels were sampled monthly using fyke nets (operated by professional fishermen), yielding a total of 509 specimens. Total length and weight were measured, sex, age and maturity stages (silver or yellow eel) were determined. Catch Per Unit Effort (CPUE) was calculated for both biomass per unit effort and numbers caught on a monthly and annual basis. The length‐weight relationships (LWRs) of silver and yellow eel was W = 0.009*TL3.22 (n = 262) and W = 0.0106*L3.09 (n = 247), respectively. The age of the sampled fish ranged from year class II to VI. Von Bertalanffy growth parameters were estimated as L∞=69.25 cm, K = 0.43 1/year, t0= −0.41 and phi prime index (ǿ)= 3.31 for all samples. The overall eel fishing mortality rate (F) was 0.31 year‐1, and the exploitation and survival rates of silver stage eels were estimated with 30% and 39%, respectively.