Stress-induced impairment of predator evasion and non-predator mortality in Pacific salmon

In two parts of the article, more than 70 errors and violations of the Biotechnics of artificial breeding of Pacific salmon in salmon hatcheries are collected and summarized, which lead to an immediate or delayed deterioration of the quality of reared fry and a decrease in their survival rate. Deviations from the biological basis of fish farming are shown and possible consequences of such errors or violations are predicted. In the first part of the article (#7,2020) there were General errors (throughout the entire fish-breeding process), as well as violations of Biotechnics during the work with producers, collecting eggs and preparing them for incubation, in the second part-violations of Biotechnics during the incubation of eggs, holding pre-larvae, rearing and release of young. Their correction, prevention or minimization of consequences will significantly improve the quality of sexual products and offspring from producers, increase the linear and weight gain of juveniles during rearing, improve the coefficient of feed payment, reduce the time of rearing, improve the epizootic situation by developing immunity in fry and mobilizing other protective reactions of their body, significantly reduce waste at all stages of the production process, increasing survival by 10–15%. In conclusion, it is noted that the first and most important condition for an efficient salmon hatchery is the creation of optimal environmental conditions at each stage of the production process. The second condition is strict compliance with the Biotechnics of artificial salmon breeding and the complex of veterinary and sanitary, fish-breeding and meliorative and therapeutic and preventive measures. The third is the availability of competent specialists who regularly improve their skills in accredited Universities to implement, control and manage the first two conditions.

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Physiological resilience of pink salmon to naturally occurring ocean acidification

Conservation Physiology ◽

10.1093/conphys/coaa059 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Andrea Y Frommel ◽

Justin Carless ◽

Brian P V Hunt ◽

Colin J Brauner

Keyword(s):

British Columbia ◽

Elevated Co2 ◽

Condition Factor ◽

Pacific Salmon ◽

Pink Salmon ◽

Hypoxia Tolerance ◽

High Co2 ◽

The North ◽

Naturally Occurring ◽

Co2 Levels

Abstract Pacific salmon stocks are in decline with climate change named as a contributing factor. The North Pacific coast of British Columbia is characterized by strong temporal and spatial heterogeneity in ocean conditions with upwelling events elevating CO2 levels up to 10-fold those of pre-industrial global averages. Early life stages of pink salmon have been shown to be affected by these CO2 levels, and juveniles naturally migrate through regions of high CO2 during the energetically costly phase of smoltification. To investigate the physiological response of out-migrating wild juvenile pink salmon to these naturally occurring elevated CO2 levels, we captured fish in Georgia Strait, British Columbia and transported them to a marine lab (Hakai Institute, Quadra Island) where fish were exposed to one of three CO2 levels (850, 1500 and 2000 μatm CO2) for 2 weeks. At ½, 1 and 2 weeks of exposure, we measured their weight and length to calculate condition factor (Fulton’s K), as well as haematocrit and plasma [Cl−]. At each of these times, two additional stressors were imposed (hypoxia and temperature) to provide further insight into their physiological condition. Juvenile pink salmon were largely robust to elevated CO2 concentrations up to 2000 μatm CO2, with no mortality or change in condition factor over the 2-week exposure duration. After 1 week of exposure, temperature and hypoxia tolerance were significantly reduced in high CO2, an effect that did not persist to 2 weeks of exposure. Haematocrit was increased by 20% after 2 weeks in the CO2 treatments relative to the initial measurements, while plasma [Cl−] was not significantly different. Taken together, these data indicate that juvenile pink salmon are quite resilient to naturally occurring high CO2 levels during their ocean outmigration.

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Frequency responses of age-structured populations: Pacific salmon as an example

Theoretical Population Biology ◽

10.1016/j.tpb.2010.07.004 ◽

2010 ◽

Vol 78 (4) ◽

pp. 239-249 ◽

Cited By ~ 27

Author(s):

Lee Worden ◽

Louis W. Botsford ◽

Alan Hastings ◽

Matthew D. Holland

Keyword(s):

Pacific Salmon ◽

Structured Populations ◽

Frequency Responses ◽

Age Structured

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Diet composition of Steller sea lions (Eumetopias jubatus) in Frederick Sound, southeast Alaska: a comparison of quantification methods using scats to describe temporal and spatial variabilities

Canadian Journal of Zoology ◽

10.1139/cjz-2014-0292 ◽

2015 ◽

Vol 93 (5) ◽

pp. 361-376 ◽

Cited By ~ 7

Author(s):

D.J. Tollit ◽

M.A. Wong ◽

A.W. Trites

Keyword(s):

Pacific Salmon ◽

Biomass Energy ◽

Eumetopias Jubatus ◽

Steller Sea Lions ◽

Southeast Alaska ◽

Merluccius Productus ◽

Sea Lions ◽

Sampling Protocols ◽

Dietary Indices

We compared eight dietary indices used to describe the diet of Steller sea lions (Eumetopias jubatus (Schreber, 1776)) from 2001 to 2004 in Frederick Sound, southeast Alaska. Remains (n = 9666 items) from 59+ species categories were identified from 1684 fecal samples (scats) from 14 collection periods. The most frequently occurring prey were walleye pollock (Theragra chalcogramma (Pallas, 1814) = Gadus chalcogrammus Pallas, 1814; 95%), Pacific herring (Clupea pallasii Valenciennes in Cuvier and Valenciennes, 1847; 30%), Pacific hake (Merluccius productus (Ayres, 1855); 29%), and arrowtooth flounder (Atheresthes stomias (Jordan and Gilbert, 1880) = Reinhardtius stomias (Jordan and Gilbert, 1880); 21%). These species, along with Pacific salmon (genus Oncorhynchus Suckley, 1861) and skate (genus Raja L., 1758), accounted for 80%–90% of the reconstructed biomass and energy contribution, with pollock contributing 37%–60%. Overall, 80% of fish were 14–42 cm long and mainly pelagic, though 40% of scats contained benthic-associated prey. Steller sea lions switched from adult pollock to strong cohorts of juvenile pollock, and took advantage of spawning concentrations of salmon in autumn and herring in late spring and summer, as well as a climate-driven increase in hake availability. Observed temporal and site differences in diet confirm the need for robust long-term scat sampling protocols. All major indices similarly tracked key temporal changes, despite differences in occurrence and biomass-energy-based diet estimates linked to prey size and energy-density effects and the application of correction factors.

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