the reproductive biology of the iranian cichlid, iranocichla hormuzensis coad, 1988, was investigated for 13 consecutive months in lower mehran river, from august 2008 through august 2009. four hundred and eighty six individuals (252 males and 234 females) were captured using a seine net (5 mm mesh size). the observed sex ratio was 1m: 0.93f (χ², df = 1, p = 0.414). mean ± sd of total length (t...

The selective pressures involved in the evolution of semelparity and its associated life-history traits are largely unknown. We used species-level analyses, independent contrasts, and reconstruction of ancestral states to study the evolution of body length, fecundity, egg weight, gonadosomatic index, and parity (semelparity vs. degree of iteroparity) in females of 12 species of salmonid fishes....

this study was carried out to determine some biological characteristics including age, growth and somatic condition of carasobarbus luteus and capoeta trutta in the turkish part of the tigris river. the examined samples of c. luteus were distributed between ii-ix years of age. the length-weigth relations of females and males were calculated as log w =-4.7314 +3.0113 log fl and log w = -4.7631 +...

This study attempts to look into the energetic status of demersal fish species with their maturity stages and evaluate their energetic condition. Demersal fish species from wild were captured, total length and weight of each fish were measured and gonads were observed, weighted and collected with fish flesh. Gonadosomatic index, water content of gonad and flesh and gonadal and somatic caloric v...

the correlation between serum steroid hormones, testosterone (t), 17β-estradiol (e2), and progesterone (p) and weight of female fishes, biological characteristics of gonad (e.g. fertilization rate, fluid egg rate, gonadosomatic index , polarization index and oocyte diameter) in 10 female of the migratory population of sterlet (acipenser ruthenus) and 5 female of the migratory population of sibe...

The fish family Cichlidae has a large diversity and dominates African freshwater bodies, with over 200 species reported in inland waters. Sampling for the fish Oreochromis niloticus (Linnaeus) in Opa reservoir, Nigeria, started in October 1997 and extended until February 2000. The fishing methods employed for collecting the 1 430 specimens were cast netting and gillnetting. Egg diameter varied ...

The sex ratio, gonadosomatic index, stages of gonadal development and fecundity of sompat grunt Pomadasys jubelini off Lagos coast, Nigeria were investigated. P. jubelini had sex ratio of 1: 0.85 (male to female). The difference in sex ratio was not significantly different (p > 0.05) from the expected 1:1 distribution. Gonadosomatic index ranged from 0.07 to 7.29% with mean of 2.25 ± 0.08%. Hig...

Champotón River is an unknown area within the Mesoamerican hotspot in Southestern México. Reproductive traits and population structure of Astyanax aeneus were analyzed along an environmental gradient of the upper, middle and lower sections of the river, where diverse environmental factors were recorded. For this, nets were cast for 1 h at each site and A. aeneus were collected from all sections...