نتایج جستجو برای: spawning effectiveness
تعداد نتایج: 329732 فیلتر نتایج به سال:
Despite a wealth of information on sexual reproduction in scleractinian corals, there are regional gaps in reproductive records. In the Gulf of the Oman in the Arabian Sea, reproductive timing was assessed in four common species of broadcast spawning corals using field surveys of gamete maturity and aquarium observations of spawning activity. The appearance of mature gametes within the same mon...
Length and age at maturity are important life history parameters for estimating spawning stock biomass and reproductive potential of fish stocks. Bias in estimates of size and age at maturity can arise when disparate distributions of mature and immature fish within a population are not accounted for in the analysis. Here we investigate the spatial and temporal variability in observed size and a...
Environmental conditions may have previously underappreciated effects on the reproductive processes of commercially exploited fish populations, for example eastern Baltic cod, that are living at the physiological limits of their distribution. In the Baltic Sea, salinity affects neutral egg buoyancy, which is positively correlated with egg survival, as only water layers away from the oxygen cons...
In the Baltic Sea the autumn spawning herring forms a smaller number of groups than the spring herring does. This is probably connected with the different location of their spawning grounds. Spawning grounds of the spring herring are concentrated in favorable sites near the coast (in gulf, estuaries, etc.) while between such spawning centers gaps occur usually. Contrary to it, in most parts of ...
We evaluated habitat features (i.e., substrate particle size, water depth, water velocity) at spawning redds and randomly selected reference locations (where spawning activity was not apparent) to determine importance of these features to rainbow trout (Oncorhynchus mykiss) spawning habitat use in the Pere Marquette River, Michigan, 1997 to 1999. Rainbow trout selected areas with small gravel, ...
This paper develops a sustainable yield harvesting model for the wild Atlantic salmon (Salmo salar), where the population comprises different age classes. It is shown that the weight– fecundity relationship of the spawning population, comprising young and old fish, is crucial for the maximum sustainable yield fishing composition. First, the optimal harvest is found when fecundity is approximate...
A model is presented that simulates the effects of streamflow and sediment transport on survival of salmonid embryos incubating in spawning gravels in a natural channel. Components of the model include a 6-yr streamflow record, an empirical bed load-transport function, a relation between transport and infiltration of sandy bedload into a gravel bed, effects of fine-sediment infiltration on grav...
BACKGROUND Fish sound production is widespread throughout many families. Territorial displays and courtship are the most common reasons for fish sound production. Yet, there is still some questions on how acoustic signaling and reproduction are correlated in many sound-producing species. In the present study, our aim was to determine if a quantitative relationship exists between calling and egg...
The aquaculture of Senegalese sole (Solea senegalensis) is limited by the failure of cultured breeders (G1 generation) to produce fertilized spawning. Critical reproductive dysfunctions have been observed in both female and male Senegalese sole cultured breeders, including reduced fecundity and diminished sperm production. The present work aimed to study the effectiveness of different hormonal ...
We re-tested stored (frozen) DNA samples in 5 independent polymerase chain reaction (PCR) replicates and confirmed that equivocal test results from a previous study on white spot syndrome virus (WSSV) in brooders and their offspring arose because amounts of WSSV DNA in the test samples were near the sensitivity limits of the detection method. Since spawning stress may trigger WSSV replication, ...
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