Abstract
This study was conducted in Lake Hayq between January and December 2018. The objectives of this study were to determine the growth, condition, sex ratio, fecundity, length at first sexual maturity (L50), and spawning seasons of common carp (Cyprinus carpio). Monthly fish samples of C. carpio were collected using gillnets of stretched mesh sizes of 4, 6, 7, 8, 10, and 13 cm and beach seines of mesh size of 6 cm. Immediately after the fish were captured, total length (TL) and total weight (TW) for each individual were measured in centimeters and grams, respectively, and their relationship was determined using power function. Length at first maturity (L50) was determined for both males and females using the logistic regression model. The spawning season was determined from the frequency of mature gonads and variation of gonadosomatic index (GSI) values of both males and females. Fecundity was analyzed from 67 mature female specimens. The length and weight relationship of C. carpio was TW = 0.015TL2.93 for females and TW = 0.018TL2.87 for males that indicate negative allometric growth in both cases. The mean Fulton condition factor (CF) was 1.23 ± 0.013 for females and 1.21 ± 0.011 for males. The value of CF in both cases was > 1 that shows both sexes are in good condition. Among the total 1055 C. carpio collected from Lake Hayq, 459 (43.5%) were females and 596 (56.5%) were males. The chi-square test showed that there was a significant deviation between male and female numbers from 1:1 ratio (χ2= 22, df = 11, P > 0.05) within sampling months. The length at first sexual maturity (L50) for females and males were 21.5 and 17.5 cm, respectively. Males mature at smaller sizes than females. The spawning season of C. carpio was extended from February to April, and the peak spawning season for both sexes was in April. The average absolute fecundity was 28,100 ± 17,462. C. carpio is currently the commercially important fish while Nile tilapia fishery has declined in Lake Hayq. Therefore, this baseline data on growth, condition, and reproductive biology of common carp will be essential to understand the status of the population of carp and design appropriate management systems for the fish stock of Lake Hayq, Ethiopia, and adjacent countries.
Highlights
Common carp (Cyprinus carpio) is one of the widely cultured commercially important freshwater fish species in the world (FAO 2013)
The length-weight relationship of both female and male C. carpio in Lake Hayq was curvilinear, and as a result, the line fitted to the data was described by the regression equation (Table 2)
Sex ratio From 1055 specimens of C. carpio collected from Lake Hayq, 459 (43.5%) were females and 596 (56.5%) were males
Summary
Common carp (Cyprinus carpio) is one of the widely cultured commercially important freshwater fish species in the world (FAO 2013). C. carpio is native to Eastern Europe and Central Asia. It can tolerate a wide range of water quality parameters. Common carp is omnivorous fish species that consume animals (aquatic insects, macroinvertebrates, and zooplankton) and plant origin (phytoplankton, macrophytes) (Rahman et al 2008, 2009; Weber and Brown 2009). C. carpio grows rapidly, achieves sexual maturation in the second year of life, and is highly fertile (about 2 million eggs per female) (Balon 1975; Hossain et al 2016).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
