Genetic Evidence of Vertical Transmission and Cycling of Yersinia ruckeri in Hatchery-Origin Fall Chinook Salmon Oncorhynchus tshawytscha

Abstract Enteric redmouth disease, caused by the bacterium Yersinia ruckeri, can be a severe problem in the culture of salmonid fishes, and can persist as a chronic infection within hatchery facilities for an indefinite amount of time ranging from months to years. Using a nested polymerase chain reaction (nPCR) assay and a real-time quantitative PCR (qPCR) assay, the prevalence of Y. ruckeri deoxyribonucleic acid (DNA) was documented across a single production cycle of fall Chinook salmon Oncorhynchus tshawytscha reared at a hatchery. Ovarian fluid from spawning female adults, unfertilized eggs, eyed eggs, sac fry, and juvenile fish all tested positive for Y. ruckeri DNA using both nPCR and qPCR assays. Presence of Y. ruckeri DNA in ovarian fluids and unfertilized eggs indicates that vertical transmission of the pathogen from females to their progeny is possible. Juvenile fish had the highest level of Y. ruckeri DNA at a log10-transformed level of 4.3 DNA copies per gram of kidney tissue. The limited mortality observed was attributed to handling and hatchery procedures during the study period and indicates that the low levels of the pathogen's DNA can persist without severe detrimental effects over the hatchery rearing cycle.

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Life in captivity: varied behavioural responses to novel setting and food types in first-generation hybrids of farmed and wild juvenile Chinook salmon (Oncorhynchus tshawytscha)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2018-0311 ◽

2019 ◽

Vol 76 (11) ◽

pp. 1962-1970

Author(s):

Kevyn Janisse ◽

Pauline M. Capelle ◽

John W. Heath ◽

Mitchel G. Dender ◽

Daniel D. Heath ◽

...

Keyword(s):

Chinook Salmon ◽

First Generation ◽

Oncorhynchus Tshawytscha ◽

Juvenile Fish ◽

Farmed Fish ◽

Behavioural Responses ◽

Growth Metrics ◽

In Captivity ◽

Behavioural Phenotypes ◽

Response To Change

Aquaculture practices continuously seek to improve efficiency to produce larger fish at lower cost. Selective breeding within brood stocks can result in undesirable effects, promoting hatcheries to use outbreeding to increase or maintain genetic diversity. This practice however, could result in the introduction of wild behavioural phenotypes unable to adapt to captive-living conditions. Using four hatchery first-generation hybrid crosses and two fully domesticated stocks of Chinook salmon (Oncorhynchus tshawytscha) in British Columbia, we examined behavioural responses to common aquaculture practices such as abrupt environmental change and novel feed types in juvenile fish. Controlling for mass, we found crosses varied in their behaviours to a novel setting and preferences for natural versus commercial diets. These differences were furthermore associated with rearing environment and stock-level growth rate and body size. Our results suggest selecting for phenotypes that behaviourally exhibit better coping mechanisms and greater flexibility in response to change is possible, and when in combination with growth metrics, should be an integral part of producing the desired farmed fish. Behaviours that allow commercial anadromous fish to easily transition to captive environmental conditions can benefit production and also animal welfare.

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The Entrainment and Screening of Returning and Postspawning Adult Salmonids at Irrigation Canals of the Umatilla River, Oregon

Journal of Fish and Wildlife Management ◽

10.3996/072017-jfwm-058 ◽

2018 ◽

Vol 9 (1) ◽

pp. 285-295

Author(s):

William G. Simpson

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Coho Salmon ◽

Juvenile Fish ◽

Irrigation Canal ◽

Irrigation Canals ◽

Water Currents ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Passive Integrated Transponders ◽

Direction Of Movement

Abstract Anadromous salmonids can be vulnerable to entrainment at diversion intake structures on streams, effectively trapping fish in irrigation canals and removing them from a population. Currently little is known about how the differences in timing and direction of movement among adult salmonids contribute to their risk of entrainment and how successful they are at escaping irrigation canals. Potential routes of escape include passing against water currents and through the headgate of an irrigation canal intake or by navigating through screen and bypass infrastructure primarily designed to return juvenile fish to a stream. In this study, passive integrated transponders (PIT tags) were used to track the movement of adult Chinook Salmon Oncorhynchus tshawytscha (n = 573), Coho Salmon Oncorhynchus kisutch (n = 39), and anadromous Rainbow Trout Oncorhynchus mykiss (steelhead, n = 853) as they entered areas of the Umatilla River basin (Oregon) with irrigation canals and as they attempted to escape irrigation canals after entrainment. Although adult steelhead and spring Chinook Salmon often encountered diversions at similar times, the vast majority of entrained adults were steelhead (94%). Between 2% and 8% of adult steelhead observed entering the area were entrained. The entrainment of steelhead was strongly associated with downstream movements and Umatilla River discharge below 40 m3/s. Many downstream-moving steelhead were postspawning fish (kelts). As a result, vulnerability of anadromous adults to entrainment differed by species due to the direction of their movements and how these movements coincide with canal operations and river flows. It is unlikely that the screened irrigation canals acted as an ecological sink; the majority of adult salmonids approached the screen and bypass infrastructure (≥88%) and later river detection confirmed that many had used that infrastructure to return to the river (≥47%). However, half of steelhead appeared to experience bypass delays at fish screens. Adult steelhead that approached the canal headgate after becoming trapped in the canal did not successfully return to the Umatilla River using this route. Unscreened irrigation canals elsewhere may disproportionally trap downstream-moving steelhead, like postspawning kelts, due to their propensity for entrainment and their difficulties escaping through the water intakes of irrigation canals. In streams with anadromous salmonids, fish screen and bypass infrastructure primarily designed to eliminate the permanent entrainment of juvenile fish can also prevent the removal of adult fish that may reproductively contribute to the population.

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Nested polymerase chain reaction for detection of Enterocytozoon salmonis genomic DNA in chinook salmon Oncorhynchus tshawytscha

Diseases of Aquatic Organisms ◽

10.3354/dao023017 ◽

1995 ◽

Vol 23 (1) ◽

pp. 17-23 ◽

Cited By ~ 23

Author(s):

JE Barlough ◽

TS McDowell ◽

A Milani ◽

L Bigornia ◽

SB Slemenda ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Chinook Salmon ◽

Genomic Dna ◽

Oncorhynchus Tshawytscha ◽

Chain Reaction ◽

Nested Polymerase Chain Reaction ◽

Polymerase Chain

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Potential of the Melanophore Pigment Response for Detection of Bacterial Toxicity

Applied and Environmental Microbiology ◽

10.1128/aem.01241-10 ◽

2010 ◽

Vol 76 (24) ◽

pp. 8243-8246 ◽

Cited By ~ 3

Author(s):

Stephanie R. Dukovcic ◽

Janine R. Hutchison ◽

Janine E. Trempy

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Aeromonas Salmonicida ◽

Brown Pigment ◽

Toxic Substances ◽

Human Pathogen ◽

Yersinia Ruckeri ◽

Cell Type ◽

Flavobacterium Psychrophilum ◽

Bacterial Toxicity

ABSTRACT Chromatophore cells have been investigated as potential biodetectors for function-based detection of chemically and biologically toxic substances. Oncorhynchus tshawytscha (chinook salmon) melanophores, a chromatophore cell type containing brown pigment, rapidly detect the salmonid pathogens Aeromonas salmonicida, Yersinia ruckeri, and Flavobacterium psychrophilum and the human pathogen Bacillus cereus.

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The effects of hatchery domestication on competitive dominance of juvenile spring Chinook salmon (Oncorhynchus tshawytscha)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f07-058 ◽

2007 ◽

Vol 64 (5) ◽

pp. 803-812 ◽

Cited By ~ 33

Author(s):

Todd N Pearsons ◽

Anthony L Fritts ◽

Jennifer L Scott

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

State Of The Art ◽

Juvenile Fish ◽

Agonistic Interactions ◽

Juvenile Chinook Salmon ◽

Domestication Selection ◽

Dominant Fish ◽

Different Types ◽

Juvenile Chinook

We tested the null hypotheses that competitive dominance among juvenile Chinook salmon (Oncorhynchus tshawytscha) in contest and scramble experiments would not be affected by domestication selection after one generation of state-of-the-art hatchery culture. Dyadic challenges of size-matched juvenile fish were conducted after a 6-day acclimation in 113.4 L aquaria. Differences in dominance and frequency of different types of agonistic interactions used were not significantly different in contest (n = 505) or scramble (n = 363) competition experiments (P > 0.05). However, wild origin fish were more aggressive than hatchery origin fish in both types of experiments (P ≤ 0.05). Furthermore, wild origin fish gained more weight than hatchery origin fish during contest experiments, and hatchery origin fish lost less weight than wild origin fish in scramble experiments (P ≤ 0.05). Dominant fish, regardless of origin, grew more than subordinate fish in both contest and scramble experiments (P ≤ 0.05). Our results indicate that aggression, and growth mediated by competition, can be affected by domestication after only one generation of state-of-the-art hatchery culture; however, impacts to competitive dominance appear to be small.

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