In the present study, the effect of successive milt collection was investigated on spermatological parameters and reproduction successes of wild and cultured endangered caspian brown trout. The milt collection was done 3 times with two weeks intervals. After milt collection, amount of milt was allocated for milt quality evaluation and reminders used for fertilization. According to results, in w...

Many studies about endocrine pollution in the aquatic environment reveal changes in the reproduction system of biota. We analysed endocrine activities in two rivers in Southern Germany using three approaches: (1) chemical analyses, (2) in vitro bioassays, and (3) in vivo investigations in fish and snails. Chemical analyses were based on gas chromatography coupled with mass spectrometry. For in ...

eurasian perch, perca fluviatilis l., is one of the most important species in european freshwater aquaculture and probably one of most important of cold freshwater species in nearest future. the aim of this study was to test the ovaprim in artificial reproduction in eurasian perch in two temperatures (12 and 14°c) with using new oocyte maturation stage system. the results obtained in present st...

The conventional view (Hoar, 1970; Liley, 1970; Harvey and Hoar, 1979) of the sequence of events which, in fish, leads to first gonadal maturation and subsequent spawning, starts with "environmental stimuli" which the brain and pineal gland process and pass on to the hypothalamus, which passes its information to the pituitary; gonadotropic hormones are then synthesized and released which leads ...

Limited resources in the environment prevent individuals from simultaneously maximizing all life-history traits, resulting in trade-offs. In particular, the cost of reproduction is well known to negatively affect energy investment in growth and maintenance. Here, we investigated these trade-offs during contrasting periods of high versus low fish size and body condition (before/after 2008) in th...

The objective of this study was to determine the effect of human chorionic gonadotropin (hCG) on sexual maturation, plasma sex steroids (17β-estradiol, E2 and 17α-hydroxy progesterone (17α OHP)) and thyroid hormones (triiodothyronine, T3 and thyroxin, T4) levels in upstream - migrating Caspian lamprey. During the experiment, 36 fish (24 females and 12 males) in  spring 2013 and 36 fish (24 fema...