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At least 19 recordsLinked to original sources
PubMed2002

Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed.

This pilot study examined five commercial salmon feeds, four farmed salmon (one Atlantic, three chinooks) and four wild salmon (one chinook, one chum, two sockeyes) from the Pacific Coast for PCBs (112 congeners), polybrominated diphenylethers (PBDEs - 41 congeners), 25 organochlorine pesticides (OPs), 20 polycyclic aromatic hydrocarbons (PAHs), and methyl and inorganic mercury. The farmed salmon showed consistently higher levels of PCBs, PBDEs, OPs (except toxaphene) than the wild salmon. The mean concentrations in pg/g were 51,216 vs 5302 for total PCBs; 2668 vs 178 for total PBDEs; 41,796 vs 12,164 for total OPs (except toxaphene). The farmed salmon levels are likely a consequence of the elevated level of contamination found in the commercial salmon feed (mean concentrations in pg/g were 65,535 for total PCBs; 1889 for total BPDEs; 48,124 for total OPs except toxaphene). Except for a single high wild chinook value, PAHs were highest in the feed samples followed by the farmed fish and the three other wild fish. The Bio-Oregon-1996 feed of hatchery origin showed a level of PAHs ten times higher than any other feed. The genotoxic implications of such a high PAH level are considered for juvenile chinook salmon. Toxaphene and methyl mercury concentrations were not notably different between the wild and farmed salmon. There was no clear low contaminant brand of salmon feed. The human health implications of eating farmed salmon are considered from the perspective of the current WHO and Health Canada (2000) tolerable daily intake (TDI) values for PCBs. Based on a TDI of 1 pg TEQ/kg bw/day, this analysis indicated a safety concern for individuals who on a regular weekly basis consume farmed salmon produced from contaminated feed.

Animals↗
PubMed2003

Infectious salmon anemia virus RNA in fish cell cultures and in tissue sections of atlantic salmon experimentally infected with infectious salmon anemia virus.

Current understanding of the etiopathogenesis of infectious salmon anemia (ISA) virus (ISAV) infection in fish comes mostly from virus detection in homogenized tissues taken from ISA-suspected mortalities. This study combined in situ hybridization (ISH) and histology to demonstrate viral RNA transcripts in different fish cell lines infected with ISAV and in tissues collected during the clinical phase of ISAV infection in Atlantic salmon. For this, a riboprobe to mRNA transcripts of ISAV RNA segment 8 was shown to detect viral mRNA in ISAV-infected TO, CHSE-214, and SHK-1 cell cultures. Specific hybridization was initially detected exclusively in the nuclei of infected cells, which is consistent with the nuclear transcription of orthomyxoviruses. For use of the riboprobe on fish tissues fixed in paraformaldehyde or formalin, the conditions used to permeabilize tissues before ISH (Proteinase K or Tween 20) were first optimized. Tissues were collected 15-20 days after challenge from 7 fresh mortalities of Atlantic salmon parr (approximately 20 g) showing severe gross and microscopic lesions, consistent with ISAV infection. Reverse transcription-polymerase chain reaction on tissue pools confirmed the presence of ISAV in each of the 7 fish. Of the tissues examined in each fish, the heart and liver consistently showed the strongest hybridization signal and, therefore, the most in situ virus, which was located in the endothelium of small blood vessels and in macrophage-like cells.

Anemia↗
PubMed2002

Susceptibility of rainbow trout Oncorhynchus mykiss, Atlantic salmon Salmo salar and coho salmon Oncorhynchus kisutch to experimental infection with sea lice Lepeophtheirus salmonis.

Physiological, immunological and biochemical parameters of blood and mucus, as well as skin histology, were compared in 3 salmonid species (rainbow trout Oncorhynchus mykiss, Atlantic salmon Salmo salar and coho salmon O. kisutch) following experimental infection with sea lice Lepeophtheirus salmonis. The 3 salmonid species were cohabited in order to standardize initial infection conditions. Lice density was significantly reduced on coho salmon within 7 to 14 d, while lice persisted in higher numbers on rainbow trout and Atlantic salmon. Lice matured more slowly on coho salmon than on the other 2 species, and maturation was slightly slower on rainbow trout than on Atlantic salmon. Head kidney macrophages from infected Atlantic salmon had diminished respiratory burst and phagocytic capacity at 14 and 21 d post-infection (dpi), while infected rainbow trout macrophages had reduced respiratory burst and phagocytic capacities at 21 dpi, compared to controls. The slower development of lice, coupled with delayed suppression of immune parameters, suggests that rainbow trout are slightly more resistant to lice than Atlantic salmon. Infected rainbow trout and Atlantic salmon showed increases in mucus lysozyme activities at 1 dpi, which decreased over the rest of the study. Mucus lysozyme activities of infected rainbow trout, however, remained higher than controls over the entire period. Coho salmon lysozyme activities did not increase in infected fish until 21 dpi. Mucus alkaline phosphatase levels were also higher in infected Atlantic salmon compared to controls at 3 and 21 dpi. Low molecular weight (LMW) proteases increased in infected rainbow trout and Atlantic salmon between 14 and 21 dpi. Histological analysis of the outer epithelium revealed mucus cell hypertrophy in rainbow trout and Atlantic salmon following infection. Plasma cortisol, glucose, electrolyte and protein concentrations and hematocrit all remained within physiological limits for each species, with no differences occurring between infected and control fish. Our results demonstrate that significant differences in mucus biochemistry and numbers of L. salmonis occur between these species.

Alkaline Phosphatase↗
PubMed2002

Investigation of selected persistent organic pollutants in farmed Atlantic salmon (Salmo salar), salmon aquaculture feed, and fish oil components of the feed.

There is extensive literature documenting the bioaccumulation of persistent organic pollutants in the marine environment, but relatively little data are available on contamination pathways in aquaculture systems such as that for farmed salmon. In recent years,the salmon industry has grown significantly in Europe. This study reports on the determination of a wide range of polychlorinated biphenyls (PCBs), organochlorine pesticides, and polybrominated diphenyl ethers (PBDEs) in farmed and wild European Atlantic salmon fish, aquaculture feeds, and fish oils used to supplement the feeds. The study confirms previous reports of relatively high concentrations of PCBs and indicates moderate concentrations of organochlorine pesticides and PBDEs in farmed Scottish and European salmon. Concentrations of the selected persistent organic pollutants varied among the samples: PCBs (salmon, 145-460 ng/g lipid; salmon feeds, 76-1153 ng/g lipid; fish oils, 9-253 ng/g lipid), S DDTs (salmon, 5-250 ng/g lipid; salmon feeds, 34-52 ng/g lipid; fish oils, 11-218 ng/g lipid), and PBDEs (salmon, 1-85 ng/g lipid: salmon feeds, 8-24 ng/g lipid; fish oils, ND-13 ng/g lipid). Comparison of the samples for all groups of contaminants, except for HCHs, showed an increase in concentration in the order fish oil < feed < salmon. Homologue profiles were similar, with an increase in contribution of hepta- and octa-PCBs in the fish, and profiles of DDTs were similar in all three types of samples. With a constant contribution to the total PCB content, the ICES 7 PCBs appear to be reliable predictors of the PCB contamination profile through all the samples. For PBDEs, BDE 47 dominated the profiles, with no significant difference in the PBDE profiles for the three matrixes. Samples with higher PCB contents generally showed higher levels of the pesticide residues, but this was not the case with the PBDEs, indicating the existence of different pollution sources.

Animal Feed↗
PubMed2000

Characterization of proteases in the skin mucus of Atlantic salmon (Salmo salar) infected with the salmon louse (Lepeophtheirus salmonis) and in whole-body louse homogenate.

As part of an investigation of the biochemical interactions between the salmon louse Lepeophtheirus salmonis and Atlantic salmon Salmo salar, we characterized protease activity in the skin mucus of noninfected Atlantic salmon and Atlantic salmon infected with L. salmonis and in an L. salmonis whole-body homogenate. Zymography revealed that mucus from infected salmon contained a series of low-molecular-mass (17-22 kDa) serine proteases that were not present in the mucus of noninfected salmon. Based on molecular mass, inhibition studies, and affinity chromatography, the series of proteases was identified as being trypsin-like. Similar proteases were observed in the L. salmonis homogenate and in mucus from noninfected Atlantic salmon following a 1-hr incubation with live L. salmonis. An antibody raised against Atlantic salmon trypsin failed to recognize any proteases in the mucus of noninfected salmon or infected salmon or in the L. salmonis homogenate. Collectively, these findings suggest that the trypsin-like proteases present in the mucus of infected Atlantic salmon were produced by L. salmonis, possibly to aid in feeding and evasion of host immune responses.

Animals↗
PubMed1997

The salmon SmaI family of short interspersed repetitive elements (SINEs): interspecific and intraspecific variation of the insertion of SINEs in the genomes of chum and pink salmon.

The genomes of chum salmon and pink salmon contain a family of short interspersed repetitive elements (SINEs), designated the salmon SmaI family. It is restricted to these two species, a distribution that suggests that this SINE family might have been generated in their common ancestor. When insertions of the SmaI SINEs at 10 orthologous loci of these species were analyzed, however, it was found that there were no shared insertion sites between chum and pink salmon. Furthermore, at six loci where SmaI SINEs have been species-specifically inserted in chum salmon, insertions of SINEs were polymorphic among populations of chum salmon. By contrast, at four loci where SmaI SINEs had been species-specifically inserted in pink salmon, the SINEs were fixed among all populations of pink salmon. The interspecific and intraspecific variation of the SmaI SINEs cannot be explained by the assumption that the SmaI family was amplified in a common ancestor of these two species. To interpret these observations, we propose several possible models, including introgression and the horizontal transfer of SINEs from pink salmon to chum salmon during evolution.

Animals↗
PubMed1998

Ontogenic development of salmon GnRH and chicken GnRH-II systems in the brain of masu salmon (Oncorhynchus masou).

Ontogenic development of salmon gonadotropin-releasing hormone (GnRH) and chicken GnRH-II systems in masu salmon (Oncorhynchus masou) was examined. Salmon GnRH was first detected by radioimmunoassay in the embryo on day 36 after fertilization. Salmon GnRH-immunoreactive fibers were detected initially by immunocytochemistry in the vicinity of the olfactory placode of the embryo (day 36) and were distributed widely in the brain as well as in the pituitary gland of fish just after hatching (day 80). Salmon GnRH-immunoreactive neuronal somata were first detected about 6 months after fertilization in the rostroventral brain area, ranging from the olfactory nerve to the preoptic area. Salmon GnRH neuronal somata were detected earlier by in situ hybridization than by immunocytochemistry. Neuronal somata expressing salmon GnRH mRNA were first detected in the vicinity of the olfactory epithelium on day 40 and then were seen to be migrating from the olfactory epithelium, along the olfactory nerve, on day 60 and in the transitional area between olfactory nerve and olfactory bulb on day 80. In the brain, these neurons were first detected in the ventral olfactory bulb on day 80, and thereafter they were also detected in the caudal brain regions. The chicken GnRH-II system was detected later than the salmon GnRH system; chicken GnRH-II was first detected by radioimmunoassay on day 57, and chicken GnRH-II-immunoreactive fibers were first detected on day 67. Chicken GnRH-II-immunoreactive neuronal somata were not detected during the observation period. These results suggest that salmon GnRH neurons derive from the olfactory placode and then migrate into the brain and that salmon GnRH is synthesized before chicken GnRH-II.

Animals↗
PubMed2006

PCBs, PCDD/Fs, and organochlorine pesticides in farmed Atlantic salmon from Maine, eastern Canada, and Norway, and wild salmon from Alaska.

Farmed Atlantic salmon (Salmo salar) from Maine and eastern Canada, wild Alaskan Chinook salmon (Oncorhynchus tshawytscha), and organically farmed Norwegian salmon samples were analyzed for the presence of polychlorinated biphenyls (PCBs), dioxin-like PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzo-p-furans (PCDFs), and chlorinated pesticides. PCDD and PCDF congeners were not detected in > 80% of the samples analyzed. Total PCB concentrations (7.2-29.5 ng/g, wet weight, ww) in the farmed salmon were significantly higher than those in the wild Alaskan Chinook samples (3.9-8.1 ng/g, ww). Concentrations of PCBs, WHO PCB TEQs, and chlorinated pesticides varied significantly by region. PCB and WHO PCB TEQ concentrations in farmed salmon from eastern Canada were lower than those reported in samples collected two years earlier, possibly reflecting recent industry efforts to lower contaminant concentrations in feed. Organically farmed Norwegian salmon had the highest concentrations of PCBs (mean: 27 ng/g, ww) and WHO PCB TEQs (2.85 pg/g,ww); their TEQ values are in the higher range of those reported in farmed salmon from around the world. Removal of skin from salmon fillets resulted in highly variable reductions of lipids and contaminants, and in some skin-off samples, contaminant levels were higher, suggesting that skin removal does not protect the consumer from health risks associated with consumption of farmed salmon.

Alaska↗
PubMed2000

Changes in hydrolytic enzyme activities of naïve Atlantic salmon Salmo salar skin mucus due to infection with the salmon louse Lepeophtheirus salmonis and cortisol implantation.

The changes in the activities of mucus hydrolytic enzymes and plasma cortisol levels were examined following infection of Atlantic salmon Salmo salar with the salmon louse Lepeophtheirus salmonis and these changes were compared with those resulting from elevated plasma cortisol. Salmon were infected at high (Trial 1; 178 +/- 67) and low (Trial 2; 20 +/- 13) numbers of lice per fish and the activities of proteases, alkaline phosphatase, esterase and lysozyme in the mucus, as well as plasma cortisol levels were determined. At both levels of infection, there were significant increases of protease activity over time (1-way K-WANOVA; Trial 1, p = 0.004; Trial 2, p < 0.001). On several sampling days, generally on later days in the infections, the mucus protease activities of infected fish were significantly higher than control fish (Student's t-tests; p < 0.05). In addition, zymography experiments demonstrated bands of proteases at 17 to 22 kDa in the mucus of infected salmon that were absent in the mucus from non-infected fish and absent in the plasma of salmon. The intensity of these protease bands increased in the mucus over the course of both infections. However, plasma cortisol levels were elevated only in the heavily infected fish from the first trial. At high infection levels (Trial 1), alkaline phosphatase activity was higher in the mucus of infected fish at all days (t-test, p < 0.05). However, at the lower infection level (Trial 2), the mucus alkaline phosphatase activity did not differ significantly between infected and non-infected fish. Esterase and lysozyme activities were very low and did not change with time nor between non-infected and infected salmon in either challenge. Mucus enzyme activities of cortisol-implanted salmon did not change over time, nor were there any differences in activities between cortisol-implanted and control salmon. The present study demonstrates biochemical changes resulting from sea lice infection of Atlantic salmon occurring at the site of host-pathogen interaction, the mucus layer. However, the origin of these enzymes, whether host or pathogen, remains to be determined.

Alkaline Phosphatase↗
PubMed2001

Isolation and identification of infectious salmon anaemia virus (ISAV) from Coho salmon in Chile.

The isolation of infectious salmon anaemia virus (ISAV) from asymptomatic wild fish species including wild salmon, sea trout and eel established that wild fish can be a reservoir of ISAV for farmed Atlantic salmon. This report characterizes the biological properties of ISAV isolated from a disease outbreak in farmed Coho salmon in Chile and compares it with ISAV isolated from farmed Atlantic salmon in Canada and Europe. The virus that was isolated from Coho salmon tissues was initially detected with ISAV-specific RT-PCR (reverse transcription-polymerase chain reaction). The ability of the virus to grow in cell culture was poor, as cytopathology was not always conspicuous and isolation required passage in the presence of trypsin. Virus replication in cell culture was detected by RT-PCR and IFAT (indirect fluorescent antibody test), and the virus morphology was confirmed by positive staining electron microscopy. Further analysis of the Chilean virus revealed similarities to Canadian ISAV isolates in their ability to grow in the CHSE-214 cell line and in viral protein profile. Sequence analysis of genome segment 2, which encodes the viral RNA polymerase PB1, and segment 8, which encodes the nonstructural proteins NS1 and NS2, showed the Chilean virus to be very similar to Canadian strains of ISAV. This high sequence similarity of ISAV strains of geographically distinct origins illustrates the highly conserved nature of ISAV proteins PB1, NS1 and NS2 of ISAV. It is noteworthy that ISAV was associated with disease outbreaks in farmed Coho salmon in Chile without corresponding clinical disease in farmed Atlantic salmon. This outbreak, which produced high mortality in Coho salmon due to ISAV, is unique and may represent the introduction of the virus to a native wild fish population or a new strain of ISAV.

Animals↗
PubMed2004

Lack of evidence of infectious salmon anemia virus in pollock Pollachius virens cohabitating with infected farmed Atlantic salmon Salmo salar.

The infectious salmon anemia (ISA) virus causes lethargy, anemia, hemorrhage of the internal organs, and death in farmed Atlantic salmon Salmo salar. It has been a cause of disease in Norwegian farmed Atlantic salmon since 1984 and has since been identified in Canada, Scotland, the United States, and the Faroe Islands. Wild fish have been proposed as a viral reservoir because they are capable of close contact with farmed salmon. Laboratory studies have shown that brown trout and sea trout Salmo trutta, rainbow trout Oncorhynchus mykiss, and herring Clupea harengus tested positive for the virus weeks after intra-peritoneal injection of the ISA virus. Pollock Pollachius virens are commonly found in and around salmon cages, and their close association with the salmon makes them an important potential viral reservoir to consider. The objective of this study was to determine the presence or prevalence of ISA virus in pollock cohabitating with ISA-infected farmed Atlantic salmon. Kidney tissue from 93 pollock that were living with ISA-infected salmon in sea cages were tested with reverse transcription-polymerase chain reaction (RT-PCR) test. Results yielded the expected 193 bp product for positive controls, while no product was observed in any of the pollock samples, resulting in an ISA viral prevalence of 0%. This study strengthens the evidence that pollock are unlikely to be an ISA virus reservoir for farmed Atlantic salmon.

Animals↗
PubMedDate not supplied

Acute toxicity of boron, molybdenum, and selenium to fry of chinook salmon and coho salmon.

The acute toxicities of boron, molybdenum, and various forms of selenium, individually and in environmentally relevant mixtures, to swim-up and advanced fry of chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) were determined in site-specific fresh and brackish waters. Boron and molybdenum were relatively non-toxic (96-hr LC50s greater than 100 mg/L) to both life stages of both species. Selenite was significantly more toxic than selenate to both species. Swim-up fry tested in fresh water were significantly more sensitive than advanced fry in brackish water to selenate and selenite. No mortalities occurred in any concentrations tested of seleno-DL-methionine; however, in the highest concentration (21.6 mg Se/L), at least 50% of the fish showed pronounced surfacing behavior. Coho salmon were more sensitive than chinook salmon to both selenate and selenite at either life stage; only the swim-up fry of coho salmon were more sensitive than chinook salmon to boron. In additional tests with swim-up chinook salmon, differences in the characteristics of the dilution water did not significantly modify the relative toxicities of boron, selenate, and selenite. In binary mixture studies, the joint acute toxic action of selenate and selenite, combined in various ratios, was additive to both species. Based on a comparison of the individual acute values for chinook salmon to the expected environmental concentrations, the margin of safety for boron was only 56 in fresh and 46 in brackish water. The margins of safety for selenate and selenite exceeded 275 in both fresh and brackish waters. However, the margin of safety for both selenate and selenite in the mixture test was 145 in fresh water and 220 in brackish water.

Animals↗
PubMed2005

Polychlorinated biphenyls in salmon and salmon feed: global differences and bioaccumulation.

Concentrations of 160 polychlorinated biphenyl (PCB) congeners or congener groups were determined in approximately 600 farmed Atlantic salmon from around the world and wild (ocean-caught) Pacific salmon from the Northeast Pacific. Concentrations and PCB congener profiles were analyzed to provide insight into the sources and uptake of PCBs in salmon as well as regional differences. Although total PCB concentrations in wild salmon appeared to be correlated to total lipid content, the increased proportion of total lipids in the farmed salmon could not account for the much greater PCB concentrations. We investigated the PCB congener patterns of hundreds of salmon samples using principal component analysis to further illuminate regional and species differences. Three major PCB patterns were observed, in most wild fish (except British Columbia and Oregon chinook), in farmed fish from the Atlantic, and in most farmed fish from the Pacific. The PCB congener profiles of farmed salmon often closely corresponded to a sample of commercial feed purchased in the same region, indicating that the feed is likely to be the major source of PCBs for farmed salmon. In such cases where PCB profiles in fish and feed were similar, a comparison of congener concentrations in fish and the feed showed that the majority of congeners, with some notable exceptions, were bioaccumulative to the same extent, irrespective of physical properties.

Animal Feed↗
PubMed2003

Relative resistance of Pacific salmon to infectious salmon anaemia virus.

Infectious salmon anaemia (ISA) is a major disease of Atlantic salmon, Salmo salar, caused by an orthomyxovirus (ISAV). Increases in global aquaculture and the international movement of fish made it important to determine if Pacific salmon are at risk. Steelhead trout, Oncorhynchus mykiss, and chum, O. keta, Chinook, O. tshawytscha, coho, O. kisutch, and Atlantic salmon were injected intraperitoneally with a high, medium, or low dose of a Norwegian strain of ISAV. In a second challenge, the same species, except chum salmon, were injected with a high dose of either a Canadian or the Norwegian strain. Average cumulative mortality of Atlantic salmon in trial 1 was 12% in the high dose group, 20% in the medium dose group and 16% in the low dose group. The average cumulative mortality of Atlantic salmon in trial 2 was 98%. No signs typical of ISA and no ISAV-related mortality occurred among any of the groups of Oncorhynchus spp. in either experiment, although ISAV was reisolated from some fish sampled at intervals post-challenge. The results indicate that while Oncorhynchus spp. are quite resistant to ISAV relative to Atlantic salmon, the potential for ISAV to adapt to Oncorhynchus spp. should not be ignored.

Animals↗
PubMed1996

Characterization of species-specifically amplified SINEs in three salmonid species--chum salmon, pink salmon, and kokanee: the local environment of the genome may be important for the generation of a dominant source gene at a newly retroposed locus.

Short interspersed repetitive elements (SINEs), known as the HpaI family, are present in the genomes of all salmonid species (Kido et al., Proc. Natl. Acad. Sci. USA 1991, 88: 2326-2330). Recently, we showed that the retropositional efficiency of the SINE family in the lineage of chum salmon is extraordinarily high in comparison with that in other salmonid lineages. (Takasaki et al., Proc. Natl. Acad. Sci. USA 1994, 91: 10153-10157). To investigate the reason for this high efficiency, we searched for members of the HpaI SINE family that have been amplified species-specifically in pink salmon. Since the efficiency of the species-specific amplification in pink salmon is not high and since other members of the same subfamily of SINEs were also amplified species-specifically in pink salmon, the actual sequence of this subfamily might not be the cause of the high retropositional efficiency of SINEs in chum salmon. Rather, it appears that a highly dominant source gene for the subfamily may have been newly created by retroposition, and some aspect of the local environment around the site of retroposition may have been responsible for the creation of this dominant source gene in chum salmon. Furthermore, a total of 11 sequences of HpaI SINEs that have been amplified species-specifically in three salmon lineages was compiled and characterized. Judging from the distribution of members of the same-sequence subfamily of SINEs in different lineages and from the distribution of the different-sequence subfamilies in the same lineage, we have concluded that multiple dispersed loci are responsible for the amplification of SINEs. We also discuss the additional possibility of horizontal transmission of SINEs between species. The availability of the sets of primers used for the detection of the species-specific amplifications of the SINEs provides a convenient and reliable method for identification of these salmonid species.

Animals↗
PubMed1997

Distinct promoter sequences of two precursor genes for salmon gonadotropin-releasing hormone in masu salmon.

Two types of genes encode salmon gonadotropin-releasing hormone (sGnRH), which is thought to act on both sexual maturation and reproductive behavior, in salmonids. We characterized the two sGnRH genes (sGnRH-I and -II) and their upstream regions in masu salmon, Oncorhynchus masou, since such information is a prerequisite for molecular approaches to salmon reproduction. The two genes have similar exon-intron structures composed of four exons and three introns. Sequence analyses of the two genes showed that coding regions are highly conserved, but upstream regions are distinctively divergent. In the upstream regions, only the sGnRH-II gene has a large palindromic sequence, which has been proposed to be involved in control of transcription via estrogen receptors. In contrast, the sGnRH-I gene is missing the large palindromic sequence, but has three distinct palindromes in the upstream region. These results may suggest divergent transcription regulatory mechanisms between the two sGnRH genes in masu salmon. The differences in the upstream regions of sGnRH genes in Atlantic salmon (Salmo salar), sockeye salmon (Oncorhynchus nerka) and masu salmon are discussed with respect to the evolution of sGnRH genes in salmonid fish.

Animals↗