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 king scallop Pecten maximus is a high valuable species of great interest in Europe for both fishery and aquaculture. Notably, there has been an increased investment to produce seed for enhancement programmes of wild scallop populations. However, hatchery production is a relatively new industry and it is still underdeveloped. Major hurdles are spawning control and gamete quality. In the pres...

Ultrastructural studies on oocyte development and vitellogenesis in oocytes, and the functions of follicle cells during oogenesis and oocyte degeneration were investigated to clarifyb the reproductive mechanism on vitellogenesis of Scapharca subcrenata using electron microscope observations. In this study, vitellogenesis during oogenesis in the oocytes occured by way of autosynthesis and hetero...

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, ...

Enhancement projects within anadromous salmonid rivers of California have increased in recent years. Much of this work is intended as mitigation in regulated streams where salmon and steelhead spawning habitat is inaccessible or degraded due to dams, water diversions and channelization. Little research has been done to assess the benefits of spawning habitat enhancement to stream organisms othe...

The selection of spawning depth by Eurasian perch Perca fluviatilis was investigated in an experiment using artificial substrata in Lake Constance during the spawning season of 2007. The experiment compared spawning behaviour at substrata between 0.5 and 15 m depth at two sites exposed to different regimes of ship-generated wave action. The total abundance of egg ribbons did not differ signific...

Among fishes, courtship behaviour and nesting defense are strong predictors of reproductive success. We conducted three experiments to assess the impacts of exposure to 17α-ethynylestradiol (EE2) on the ability of male fathead minnows (Pimephales promelas) to establish and defend a spawning territory. Fish were exposed to EE2 (2 or 8 ng L-1) for 27 days, while spawning conditions were gradually...

In this lesson, students will learn methods for spawning bivalve mollusks (e.g. clams or oysters) using thermal induction. Students will acquire skills in using an ocular micrometer to measure the diameter of bivalve eggs and the length of bivalve larvae. The following lesson plan will have students monitoring the density of larvae in their culture system and understanding production protocols ...

this study aimed to investigate the spawning season, length at first maturity (lm 50 ) and sex ratio of metapenaeus affinis in the shrimp fishing grounds of hormozgan province, west of the persian gulf, iran. samples were taken by the swept area method and trawl net with 2 cm mesh size in the cod end from january 2010 to february 2011. results showed that the sex ratio deviated from 1:1 and fem...