Salmon Embryo Research Articles

Cultural characteristics of salmonid alphaviruses – influence of cell line and temperature

Laboratory studies were carried out to investigate the cultural characteristics of salmonid alphaviruses (SAV) from Atlantic salmon (AS, Salmo salar) and rainbow trout (RT, Oncorhynchus mykiss), particularly in relation to cell line and temperature. In an initial study, SAV was isolated from 12 viraemic sera and passaged in Chinook salmon embryo (CHSE-214) cells at 15 degrees C. Geometric mean titres (GMT) after initial isolation were found to be significantly higher (P < 0.05) relative to those after two or four passages. Primary isolation of SAV was conducted from 12 viraemic sera (six AS and six RT) in seven different cell lines at 15 degrees C: CHSE-214, rainbow trout gonad (RTG-2), TO (derived from Atlantic salmon head kidney leucocytes), salmon head kidney (SHK-1), blue fin-2 (BF-2), fat head minnow (FHM) and Epithelioma papulosum cyprini (EPC). Overall, significant differences were found between cell lines in both the numbers of strains where growth was detected and in the GMT obtained. For both AS and RT strains, GMT values were significantly (P < 0.01) higher in both TO and BF-2 cells relative to the others, including CHSE-214 and RTG-2, the cell lines conventionally used for SAV. The effects of temperature of incubation (4, 10, 15 and 20 degrees C) on growth in TO, CHSE-214 and RTG-2 were investigated. In TO and RTG-2 growth was optimal at 15 degrees C, whereas in CHSE-214 results at 10 and 15 degrees C were more similar. Little or no growth was detected at 4 or 20 degrees C.

Comparison of Temperature Data Collected from Artificial Chinook Salmon Redds and Surface Water in the Snake River

AbstractDuring three incubation periods, we collected temperature data from within artificial redds constructed in known spawning locations of Chinook salmon Oncorhynchus tshawytscha and from the surface water of the Snake River. Our objectives were to compare the data to determine (1) whether estimates of fry emergence timing differed between the two environments and (2) whether surface water data could be used to predict thermal conditions within redds. Statistical tests indicated that no differences could be detected between accumulated thermal units calculated from intraredd and surface water data (all P ≥ 0.06). We observed very little diel thermal fluctuation or daily difference within and between environments. Regression of intraredd temperature on surface water temperature was significant (r2 ≥ 0.98; all P &lt; 0.01), indicating that surface water temperature data can be used to predict intraredd temperature. We conclude that it is feasible to use surface water temperature as a surrogate for intraredd temperature in estimating Chinook salmon embryo developmental timing within the Snake River and potentially in other large rivers.

Distribution of marine birnavirus in cultured olive flounder Paralichthys olivaceus in Korea

Surveys of marine birnavirus (MABV) were undertaken in cultured olive flounder Paralichthys olivaceus from the south and west coastal areas and Jeju in Korea during the period January 1999 to April 2007. MABV was detected in all seasons from the fry, juveniles and adult fish from the areas examined. Evident cytopathic effects of the virus including rounding and cell lysis were observed in chinook salmon embryo (CHSE-214) and rainbow trout gonad (RTG-2) cells, but not in fathead minnow (FHM) and epithelial papilloma of carp (EPC) cells. Nucleotide sequences of the VP2/NS junction region of the Korean isolates showed 97.8% ~ 100% similarity, and they belonged to the same genogroup. Cross neutralization tests with serotype-specific rabbit antisera against MABV strains exhibited a close antigenic relationships between strains, and were distinct from infectious pancreatic necrosis virus (IPNV) strains. Coinfection of MABV with bacteria (Streptococcus iniae, Vibrio spp.) and viruses (nervous necrosis virus, lymphocystis disease virus, viral hemorrhagic septicemia virus) was observed.

Novel fugu U6 promoter driven shRNA expression vector for efficient vector based RNAi in fish cell lines

In fish species, although many studies on the use of RNA interference (RNAi) for gene function analysis have been reported, almost of them have utilized in vitro transcribed or synthesized small interfering RNA (siRNA), and there are a few studies which examined vector based RNAi in fish species. In this study, we have identified U6 promoter of fugu ( Takifugu rubripes), and utilized it for expression of short hairpin RNA (shRNA) in fish cell lines. Using Northern blot analysis, we confirmed successful transcription of shRNA by fugu U6 promoter in bluegill fry (BF-2) cells. The knock down assay targeting an exogenous EGFP reporter gene demonstrated that fugu U6 promoter expressed shRNA more efficiently than mouse U6 promoter in BF-2, grunt fin (GF), and Chinook salmon embryo (CHSE) cell lines. This study suggests that fugu U6 promoter driven shRNA expression vector can be novel tool for RNAi induction in fish cell lines.

Cytogenetic studies in Atlantic salmon and rainbow trout embryos

Bolla. S. 1987. Cytogenetic studies in Atlantic salmon and rainbow trout embryos. - Hereditas 106: 11–17. Lund, Sweden. ISSN 0018–0661. Received February 21, 1986 Haploid and diploid embryos of Atlantic salmon and rainbow trout in the process of development from the gastrula stage to 2/3 of the yolk sack resorption were incubated in colchicin to accumulate cells in the metaphase stage. Haploid karyograms were useful to describe the chromosome distribution. A stable chromosome number was found in salmon, whereas rainbow trout presented more variation. A large part of the inter- and intraindividual variation in chromosome number is associated with a variation of NF. Associations between acrocentrics were frequently noted in metaphases and could partially explain the extended Robertsonian polymorphism described in salmonids. No evidence of sex chromosomes was detected in the two species.

Binding of infectious pancreatic necrosis virus (IPNV) to membrane proteins from different fish cell lines

The early interactions between infectious pancreatic necrosis virus (IPNV) from Atlantic salmon and susceptible cell lines were studied using a virus overlay protein binding assay (VOPBA). Membrane preparations from four different cell lines, bluegill fry (BF)-2 cells, Chinook salmon embryo (CHSE)-214 cells, salmon head kidney (SHK)-1 cells and Atlantic salmon kidney (ASK) cells were separated by SDS-PAGE, blotted to nitrocellulose membranes and incubated with either a highly virulent IPNV field isolate or different recombinant IPNV strains exhibiting variations in virulence. Binding of virus to the respective membrane fractions was detected using either polyclonal or monoclonal antibodies. Independent of variations in virulence, IPNV bound in a specific manner to an approximately 220-kDa membrane protein from the salmonid cell lines CHSE-214, SHK-1 and ASK, whereas the size of the binding protein from the non-salmonid cell line BF-2 was approximately 190 kDa. Neutralization of IPNV prior to incubation with the blotted membrane fractions inhibited binding to the indicated proteins. Complete deglycosylation of the membrane proteins did not interfere with the binding of IPNV, suggesting that the interaction between virus and cells is not carbohydrate specific. The described binding proteins may represent putative cellular binding sites or receptors for IPNV.

Bacterial DNA indicated as an important inducer of fish cathelicidins

Cathelicidins are antimicrobial peptides indicated as important in the control of the natural microflora as well as in the fight against bacterial invasion in mammals. Little is known about cathelicidins in fish and here the Chinook salmon ( Oncorhynchus tshawytscha) embryo cell line (CHSE-214) was used as a model system to study the expression of cathelicidins due to fish pathogenic bacteria. The cDNA of cathelicidin from CHSE-214 cells (csCath) was cloned and shown to be closely related to gene 2 of both rainbow trout and Atlantic salmon. The deducted amino acid sequence showed highest sequence identity to rtCath2 with 95% and 72% for the cathelin and the antibacterial part, respectively. Cathelicidin gene expression was studied and various Gram positive and Gram negative bacteria caused the upregulation of the gene (csCath). Bacterial DNA and protein were shown important for the induction of cathelicidin expression in these cells. LPS ( Escherichia coli) also causes the upregulation of cathelicidins, but digestion of the LPS with DNase I before incubation of the cells, totally abolished the upregulation of cathelicidin and suggests DNA contamination in the LPS to be the trigger for this effect. These results could explain the limited responsiveness of fish cells towards pure LPS and confirm previous suggestions that fish cells are less sensitive to LPS than mammalian cells.

Characteristics of the adaptive response in cultured salmon cells exposed to ionizing radiation

The aim of this study was to investigate the influence of "priming" doses of ionizing irradiation on salmon cell survival in vitro prior to being challenged with subsequent higher doses. A radiation-induced adaptive response (AR) was examined in the Chinook salmon embryo cell line (CHSE-214). Cells were initially irradiated with a range of priming (conditioning) doses of (60)Co gamma (gamma) rays (0.25-0.75 Gy), followed by a challenge dose of 7.50 Gy at intervals of 24, 48, and 72 hr. The AR was assessed using a colony-forming assay. Cell survival was determined by counting the number of colonies (viable clones) after 40 days of culture. This study revealed that cells that received a priming dose of 0.50 Gy before delivering the higher challenge dose became more radiation resistant with an increase in cell survival of 29% over cells receiving the challenge dose alone. The cells showed maximum resistance to ionizing radiation when the priming dose was given 72 hr prior to the higher challenge dose. This study is one of the first to demonstrate an AR using an in vitro piscine system, and is generally consistent with other studies of both in vitro and in vivo systems across the taxa.

Sortase inhibitor phenyl vinyl sulfone inhibits Renibacterium salmoninarum adherence and invasion of host cells

Renibacterium salmoninarum, the causative agent of bacterial kidney disease in salmonid fishes, is a Gram-positive diplococcobacillus belonging to the family Micrococcaceae. Analysis of the genome sequence of the bacterium demonstrated the presence of a sortase homolog (srtD), a gene specifying an enzyme found in Gram-positive bacteria and required for covalent anchoring of cell surface proteins. Interference of sortase activity is being examined as a target for therapeutic prevention of infection by several pathogenic Gram-positive bacterial species. In silico analysis identified 8 open reading frames containing sortase recognition motifs, suggesting these proteins are translocated to the bacterial cell wall. The sortase and potential sortase substrate genes are transcribed in R. salmoninarum, suggesting they encode functional proteins. Treatment of R. salmoninarum with phenyl vinyl sulfone (PVS) significantly reduced bacterial adherence to Chinook salmon fibronectin. In addition, the ability of the PVS-treated bacteria to adhere to Chinook salmon embryo cells (CHSE-214) in vitro was dramatically reduced compared to that of untreated bacteria. More importantly, PVS-treated bacteria were unable to invade and replicate within CHSE-214 cells (demonstrated by an intracellular growth assay and by light microscopy). When treated with PVS, R. salmoninarum was not cytopathic to CHSE-214 cells, whereas untreated bacteria produced cytopathology within a few days. These findings clearly show that PVS, a small molecule drug and a known sortase inhibitor, can interfere with the ability of R. salmoninarum to adhere and colonize fish cells, with a corresponding decrease in virulence.

The Atlantic salmon Z‐DNA binding protein kinase phosphorylates translation initiation factor 2 alpha and constitutes a unique orthologue to the mammalian dsRNA‐activated protein kinase R

The translation initiation factor 2 alpha (eIF2alpha)-kinase, dsRNA-activated protein kinase (PKR), constitutes one of the major antiviral proteins activated by viral infection of vertebrates. PKR is activated by viral double-stranded RNA and subsequently phosphorylates the alpha-subunit of translation initiation factor eIF2. This results in overall down regulation of protein synthesis in the cell and inhibition of viral replication. Fish appear to have a PKR-like protein that has Z-DNA binding domains instead of dsRNA binding domains in the regulatory domain, and has thus been termed Z-DNA binding protein kinase (PKZ). We present the cloning of the Atlantic salmon PKZ cDNA and show its upregulation by interferon in Atlantic salmon TO cells and poly inosinic poly cytodylic acid in head kidney. We also demonstrate that recombinant Atlantic salmon PKZ, expressed in Escherichia coli, phosphorylates eIF2alphain vitro. This is the first demonstration that PKZ is able to phosphorylate eIF2alpha. PKZ activity, as measured by phosphorylation of eIF2alpha, was increased after addition of Z-DNA, but not by dsRNA. In addition, we show that wild-type Atlantic salmon PKZ, but not the kinase defective variant K217R, has a direct inhibitory effect on protein synthesis after transient expression in Chinook salmon embryo cells. Overall, the results support a role for PKZ, like PKR, in host defense against virus infection.

Temperature influences the coordinated expression of myogenic regulatory factors during embryonic myogenesis in Atlantic salmon (Salmo salarL.)

Potential molecular mechanisms regulating developmental plasticity to temperature were investigated in Atlantic salmon embryos (Salmo salar L.). Six orthologues of the four myogenic regulatory factors (MRFs: individually: smyf5, smyoD1a/1b/1c, smyoG and sMRF4), the master transcription factors regulating vertebrate myogenesis, were characterised at the mRNA/genomic level. In situ hybridisation was performed with specific cRNA probes to determine the expression patterns of each gene during embryonic myogenesis. To place the MRF data in the context of known muscle fibre differentiation events, the expression of slow myosin light chain-1 and Pax7 were also investigated. Adaxial myoblasts expressed smyoD1a prior to and during somitogenesis followed by smyoD1c (20-somite stage, ss), and sMRF4 (25-30 ss), before spreading laterally across the myotome, followed closely by the adaxial cells. Smyf5 was detected prior to somitogenesis, but not in the adaxial cells in contrast to other teleosts studied. The expression domains of smyf5, smyoD1b and smyoG were not confined to the s-smlc1 expression field, indicating a role in fast muscle myogenesis. From the end of segmentation, each MRF was expressed to a greater or lesser extent in zones of new muscle fibre production, the precursor cells for which probably originated from the Pax7 expressing cell layer external to the single layer of s-smlc1(+) fibres. SmyoD1a and smyoG showed similar expression patterns with respect to somite stage at three different temperatures investigated (2 degrees C, 5 degrees C and 8 degrees C) in spite of different rates of somite formation (one somite added each 5 h, 8 h and 15 h at 8 degrees C, 5 degrees C and 2 degrees C, respectively). In contrast, the expression of smyf5, sMRF4 and s-smlc1 was retarded with respect to somite stage at 2 degrees C compared to 8 degrees C, potentially resulting in heterochronies in downstream pathways influencing later muscle phenotype.

A field‐based assessment of oxygen supply to incubating Atlantic salmon (Salmo salar) embryos

AbstractOxygen fluxes through artificially created salmon redds within four UK rivers were quantified and assessed against survival to hatching of Atlantic salmon embryos. All sites recorded high spatial variability in survival. Minimum survival to hatching was zero at all sites. Maximum survival to hatching ranged from 35% to 91%. Mean survival to hatching ranged from 8·7% to 71%.Intra‐ and inter‐site variations in rates of oxygen supply were observed. Generally, interstitial dissolved oxygen concentrations declined over the incubation period from a maximum recorded directly after redd creation, although localized fluctuations were recorded. Similarly, interstitial flow velocities declined over the incubation period from a maximum directly after redd creation to a minimum at hatching. With respect to the causes of embryo mortalities, oxygen supply was shown to be a stronger determinant of survival than interstitial oxygen concentration or interstitial flow velocity.To improve delineation of potential causes of embryo mortalities in the field, the statistical analysis was integrated within mass transfer theory of the processes controlling respiration to determine the likely mechanisms inhibiting respiration. Based on this analysis, mortalities were assessed to have resulted from periods of lethal oxygen concentrations, from periods of interstitial flow velocities that were insufficient to remove metabolic waste, or from combinations of oxygen concentration and interstitial flow that did not support respiratory requirements. A set of oxygen‐supply‐related thresholds for assessing incubation habitat quality are proposed. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Oxygen as a constraining factor in egg size evolution in salmonids

Differential survival at low oxygen levels has been proposed as a mechanism for maintaining high within-population variability in egg size in fish. Whether low oxygen levels favour large or small eggs, however, is not clear. To address this question, the effects of egg size on metabolic rates, critical dissolved oxygen levels (Pc), and P50oxygen levels of Chinook salmon (Oncorhynchus tshawytscha) embryos and alevins were determined. Embryonic metabolic rate expanded at a slower rate with increasing egg mass (allometric constant (b) = 0.30) than did capsule surface area (b = 0.67), indicating that larger eggs have larger surface areas relative to their metabolic demand for oxygen. A relatively larger area, however, did not translate into significant differences in Pcor P50values at the egg stage. After hatch, metabolic rate expanded at a rate proportional to (egg mass)0.62. Pclevels were significantly higher for alevins from larger eggs for the first but not second half of the alevin stage. Egg size had no significant effect on P50values at any time during the alevin stage. The modest impact of egg size on hypoxic tolerance of developing Chinook suggests that factors other than oxygen are involved in maintaining high within-population variability in egg size.

Risk of weathered residual Exxon Valdez oil to pink salmon embryos in Prince William Sound

It has been hypothesized that pink salmon eggs incubating in intertidal streams transecting Prince William Sound (PWS) beaches oiled by the Exxon Valdez oil spill were exposed to lethal doses of dissolved hydrocarbons. Since polycyclic aromatic hydrocarbon (PAH) levels in the incubation gravel were too low to cause mortality, the allegation is that dissolved high-molecular-weight hydrocarbons (HPAH) leaching from oil deposits on the beach adjacent to the streams were the source of toxicity. To evaluate this hypothesis, we placed pink salmon eggs in PWS beach sediments containing residual oil from the Exxon Valdez oil spill and in control areas without oil. We quantified the hydrocarbon concentrations in the eggs after three weeks of incubation. Tissue PAH concentrations of eggs in oiled sediments were generally < 100 ppb and similar to background levels on nonoiled beaches. Even eggs in direct contact with oil in the sediment resulted in tissue PAH loads well below the lethal threshold concentrations established in laboratory bioassays, and very low concentrations of HPAH compounds were present. These results indicate that petroleum hydrocarbons dissolved from oil deposits on intertidal beaches are not at concentrations that pose toxic risk to incubating pink salmon eggs. The evidence does not support the hypothesis that interstitial pore water in previously oiled beaches is highly toxic.

Cytopathic effects of chum salmon reovirus to salmonid epithelial, fibroblast and macrophage cell lines

The cytopathic effect (CPE) of chum salmon reovirus (CSV), an aquareovirus, was studied in three salmonid cell lines: epithelial-like CHSE-214 from Chinook salmon embryo, fibroblast-like RTG-2, and monocyte/macrophage-like RTS11, both from rainbow trout. CHSE-214 and RTG-2 supported syncytia formation with more dramatic syncytia being observed in CHSE-214 cultures, while CSV induced homotypic aggregation (HA) in RTS11. Syncytia and HA formation were blocked by cycloheximide and ribavirin but not actinomycin D, suggesting that expression of CSV genes were required for both phenomena. Cultures with syncytia underwent a decline in cell viability, which appeared to be via apoptosis, as determined by intranucleosomal fragmentation and caspase dependence assays using the pan-caspase inhibitor, zVAD-fmk. In the presence of zVAD-fmk, CHSE-214 cultures continued to form syncytia and show diminished energy metabolism, but DNA fragmentation, the loss of membrane integrity, and the release of infectious CSV were considerably blocked. These results suggest that the formation of syncytia triggers apoptosis and a leaky plasma membrane, which enhances viral release. By contrast, RTS11 cultures undergoing HA showed no loss of cell viability. The significance of HA is unclear, but the response suggests that macrophage behaviour in rainbow trout potentially could be modulated by CSV.

Comment on "Toxicity of Weathered Exxon Valdez Crude Oil to Pink Salmon Embryos."

Comment on "Toxicity of Weathered Exxon Valdez Crude Oil to Pink Salmon Embryos."

Use of Otolith Microstructure to Discriminate Stocks of Juvenile Central Valley, California, Fall‐Run Chinook Salmon

AbstractWe examined the utility of otolith microstructure analysis as a means of discriminating among stocks and between rearing types of juvenile fall‐run Chinook salmon Oncorhynchus tshawytscha in California's Central Valley. Otolith samples were collected from 11 geographically discrete stocks of fall‐run Chinook salmon of river and hatchery rearing types over 2 years. Six measured otolith attributes and three statistics derived from these measurements served as dependent variables in a multifactor analysis of variance of paired river and hatchery stocks. Morphometrics that demonstrated no significant interaction between year and stock or rearing type were used as predictors in discriminant function analyses; 32% of samples were correctly classified by stock and 80% were correctly classified by rearing type. Measures of otolith size at fry emergence were the best predictors for distinguishing among both stocks and rearing types with discriminant function analysis. We hypothesize that observed differences in otolith size at emergence among stocks and rearing types reflect differential responses in development of Chinook salmon embryos reared under different temperature regimes. Although classification success among stocks was rather limited, results for correctly classifying fall‐run Chinook salmon by rearing type were encouraging. We suggest that observed differences in otolith microstructure between rearing types be augmented with thermal marking in Central Valley hatcheries to provide a fully reliable tool for determining the proportionate contribution of natural and hatchery production to spawner populations. This information alone would greatly advance stock management of Central Valley fall‐run Chinook salmon.

Survival, Development, and Growth of Fall Chinook Salmon Embryos, Alevins, and Fry Exposed to Variable Thermal and Dissolved Oxygen Regimes

AbstractSome fall Chinook salmon Oncorhynchus tshawytscha initiate spawning in the Snake River downstream of Hells Canyon Dam at temperatures that exceed 13°C and at intergravel dissolved oxygen concentrations that are less than 8 mg O2/L. Although water temperature declines and dissolved oxygen increases soon after spawning, the initial temperature and dissolved oxygen levels do not meet the water quality standards established by the states of Oregon and Idaho for salmonid spawning. Our objective was to determine whether temperatures from 13°C to 17°C and dissolved oxygen levels from 4 to more than 8 mg O2/L during the first 40 d of incubation followed by declining temperature and rising dissolved oxygen affected survival, development, and growth of Snake River fall Chinook salmon embryos, alevins, and fry. During the first 40 d of incubation, temperatures were experimentally adjusted downward approximately 0.2°C/d and oxygen was increased in increments of 2 mg O2/L to mimic the thermal and oxygen regime of the Snake River where these fish spawn. At 40 d postfertilization, embryos were moved to a common exposure regime that followed the thermal and dissolved oxygen profile of the Snake River through emergence. Mortality of fall Chinook salmon embryos increased markedly at initial incubation temperatures of 17°C or more, and a rapid decline in survival occurred between 16.5°C and 17°C; there were no significant differences in survival at temperatures up to 16.5°C. Initial dissolved oxygen levels as low as 4 mg O2/L over a range of initial temperatures from 15°C to 16.5°C did not affect embryo survival to emergence. There were no significant differences in alevin and fry size at hatch and emergence across the range of initial temperature exposures. The number of days from fertilization to eyed egg, hatch, and emergence was highly related to temperature and dissolved oxygen; fish required from 6 to 10 d longer to reach hatch at 4 mg O2/L than at saturation and up to 24 d longer to reach emergence. In contrast, within each dissolved oxygen treatment, fish required about 20 d longer to reach hatch at 13°C than at 16.5°C (no data were available for 17°C) and up to 41 d longer to reach emergence. Overall, this study indicates that exposure to water temperatures up to 16.5°C will not have deleterious effects on survival or growth from egg to emergence if temperatures decline at a rate of 0.2°C/d or more after spawning. Although fall Chinook salmon survived low initial dissolved oxygen levels, the delay in emergence could have significant long‐term effects on their survival. Thus, an exemption to the state water quality standards for temperature—but not oxygen—may be warranted for the portions of the Snake River where fall Chinook salmon spawn.

Experimental evidence of homing to site of incubation by mature sockeye salmon, Oncorhynchus nerka

Fish of the family Salmonidae (salmon, trout and charr) are famous for their ability to learn (‘imprint’) olfactory information as juveniles and to use those odour memories as adults to home to their natal site for reproduction years later. However, the spatial scale at which salmonids home has not been determined, and this is important not only for an understanding of the imprinting and homing processes but also because homing determines the spatial scale at which salmon populations are structured. To test the hypothesis that salmon home to specific habitat units within a single small creek, we induced banding patterns on the otoliths (ear bones) of pre-hatch sockeye salmon embryos by altering the temperatures at which they were incubated. Thermally marked embryos were buried in a small pond associated with Hansen Creek, in southwestern Alaska, and allowed to complete development and migrate. In the year when the salmon were expected to return to the creek, examination of otoliths from carcasses revealed that 12 of 324 salmon in the pond were marked, whereas all 138 salmon examined in the creek were unmarked. This distribution of marked fish indicates that more of the experimental salmon returned to the pond than would have occurred by chance, although we cannot be certain that all surviving salmon did so. These results contribute to the growing literature indicating the capacity for very fine-scale populations structure in salmon.

Effect of Fine Sediment Infiltration During the Incubation Period on Atlantic Salmon (Salmo salar) Embryo Survival

The existence of a negative relationship between fine sediment infiltration during the incubation period and salmonid embryo survival has often been discussed in the literature. However, few studies have specifically addressed this relationship in the field. We conducted a field experiment to examine the relationship between survival of Atlantic salmon (Salmo salar) embryos contained in incubation baskets and the patterns of fine sediment infiltration into the baskets during the incubation period. The results indicate that survival to pre-eyed (STPE), eyed (STE) and hatched (STH) stages of development were all negatively correlated with the percentage of fine sediment entering the baskets. STPE and STE were most strongly affected by silts and clays (<0.063 mm) although this size class represented only a small fraction of the grain size distribution inside the incubation baskets (0.03–0.41%). STH was most strongly correlated with the infiltration of medium sand (0.25–0.50 mm) material. On average, 66% of the implanted embryos survived to the pre-eyed stage of development compared to 63% for the eyed and 48% for the hatched stages of development.