Data on the abundance of spawning pink salmon (Oncorhynchus gorbuscha) are presented for rivers of southern Sakhalin Island and Iturup Island. Fluctuations in abundance are more dependent on marine survival than on the abundance of fry migrating downstream. This is explained by the favorable spawning conditions in small rivers with dense aggregations on the spawning grounds. We found stable lon...

Amphioxus is a best candidate for studying the evolutionary and developmental mechanisms of vertebrates, because of its vertebrate-like but much simpler morphology, embryonic development and genome structure. Producing live amphioxus embryos throughout the year is an ideal for comparative evolution and developmental studies. However, all amphioxus species have distinct breeding seasons in the w...

The effect of unilateral eyestalk ablation on reproduction, molting and quality of offspring was investigated in Cherax quadricarinatus females during the reproductive-arrest period (winter). At the end of the Autumn, females that had spawned for the first time had relatively uniform, early vitellogenic ovaries, while most females that had spawned previously had ovaries containing two distinctl...

Large offshore and small inshore populations of Atlantic cod Gadus morhua L. display differences in migratory patterns and settling regimes, but little is known about possible differences in spawning behaviour. Cod presumably of the Norwegian coastal cod type were therefore sampled during 7 spawning seasons (2002−2013) in Malangen, northern Norway. A spawning site in neighbouring Balsfjord was ...

The reproductive biology of albacore tuna, Thunnus alalunga, in the South Pacific Ocean was investigated with samples collected during broad-scale sampling between 2006 and 2011. Histology was done in a single laboratory according to standard protocols and the data analysed using generalized linear mixed-effects models. The sex ratio of albacore was female biased for fish smaller than approxima...

Environmental flows aim to mimic components of a river’s natural flow variability, including the magnitude, frequency, timing, duration, rate of change and the predictability of flow events. Aspects of the natural flow regime are thought to be linked to critical components of the life history strategies of many riverine fishes, including spawning and recruitment. In the Murray River, Australia,...

objective: this study was conducted with the aim to investigate and compare iranian produced and foreign oxytocin for use in induction of labor. materials and methods: this random clinical trial was conducted on a population of 198 pregnant women with live fetus and cephalic presentation and conditions conducive to induction of labor, monitored by obstetricians and gynecologists. they were rand...

Studies were undertaken to record distillery effluent induced quantitative alterations in the nucleic acids (DNA & RNA) and protein during three principal phases of ovarian cycle (prespawning, spawning and post spawning) of Colisa fasciatus , a tropical freshwater fish. Observation were recorded under three different concentrations of the distillery effluent after 30 days of exposure. Observati...

Spawning stock biomass (SSB) is one of the most common measures of stock status. However recent research on reproductive potential has shown that alternative variables may be an improvement over SSB. In the case of European hake (Merluccius merluccius), it is known that large individuals produce more eggs by unit of body weight, and their quality is better than those of small individuals. Under...

Hepatic ethoxyresorufin-O-deethylase (EROD) activity was measured in black gobies (Gobius niger) collected from seven sampling sites along the Slovenian coast during spawning and non-spawning periods. Sediments from the same sites were tested for their toxicity and for total polycyclic aromatic hydrocarbon (PAH) content. EROD activity was significantly higher during the non-spawning period in w...