River lampreys (Lampetra fluviatilis) were caught in the fall 2014 on entering Perhonjoki for spawning and kept at a hatchery until late spring 2015 to produce larvae compensatory stockings. Since died massively from early February onwards, they investigated March May clarify cause of deaths. The symptoms resembled those lipid-related thiamine (vitamin B1) deficiency salmonines, called M74 synd...

The progenetic opecoelid trematode Coitocaecum parvum can reproduce either precociously by selfing in its second intermediate amphipod host or by mating in its normal definitive fish host. In this study, we describe and compare the infection parameters and some life history traits of both egg-producing worms and non-egg producing worms in both their second intermediate and definitive hosts. We ...

Proximate analysis of broodstock and grow-out feeds for gamitana (Colossoma macropomum) and paco (Piaractus brachypomus) and their constituent feedstuffs was conducted. Literature values for specific nutrients known to affect fish reproduction were calculated from published sources for the broodstock diet. Fatty acid and amino acid profiles of broodstock eggs were obtained. Analytical informati...

The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance rat...

The present research was aimed to study the effects of different sources of carotenoids and their varying concentrations on the reproductive functions of goldfish. The study was carried out in seven treatments with three replicates at the Bony Fish Hatchery Complex (Rasht, Iran) from December 2011 to May 2012. Experimental diets containing 50, 100, and 150 mg kg-1 astaxanthin and 50, 100, and 1...

Although fertilization was observed by Fol more than 100 years ago, mechanisms for effecting a block to polyspermy in fish are largely unknown. In this review, the recent studies of polyspermy block mechanisms in teleost fish eggs will be presented, including morphological, biochemical, and molecular results.

—Praziquantel, an anthelmintic, is commonly used to control the Asian fish tapeworm Bothriocephalus acheilognathi in grass carp Ctenopharyngodon idella and baitfish. We treated 50 individuals from three different cyprinid fish species with praziquantel at 6 mg/L, a dose higher than the minimum recommended for complete Asian tapeworm removal in 24 h but much less than the concentration that woul...

The gene for vitellogenin, an egg yolk protein precursor, is usually silent in male fish but can be induced by estrogen exposure. For this reason, vitellogenin production in male fish has become a widely used indicator of exposure to exogenous estrogens or estrogen mimics in the aquatic environment. The utility of this indicator to predict impacts on fish reproductive success is unclear because...

The induction of synthesis of the "female" yolk precursor protein vitellogenin (VTG) in male fish by estrogenic chemicals in the environment has been demonstrated in many recent reports. However, little is known about the organismal and biological significance of this phenomenon. To examine the relationship between VTG production in male fish and reproductive impairment, adult male medaka were ...

We investigated occurrence, transport pathways, and effects of polybrominated diphenyl ether (PBDE) flame retardants and other endocrine disrupting chemicals (EDCs) in aquatic media and the foodweb in the lower Columbia River. In 2009 and 2010, foodweb sampling at three sites along a gradient of contaminant exposure near Skamania (Washington), Columbia City (Oregon) and Longview (Washington) in...