A novel pattern of smoltification in the most anadromous salmonid: pink salmon (Oncorhynchus gorbuscha)

2013 ◽  
Vol 70 (3) ◽  
pp. 349-357 ◽  
Author(s):  
Z.S. Gallagher ◽  
J.S. Bystriansky ◽  
A.P. Farrell ◽  
C.J. Brauner
Keyword(s):  
Fresh Water ◽  
Salinity Tolerance ◽  
Pink Salmon ◽  
Yolk Sac ◽  
Whole Body ◽  
Oncorhynchus Gorbuscha ◽  
Two Stage ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
First Time ◽  
Osmoregulatory Ability

Pink salmon (Oncorhynchus gorbuscha) enter seawater earlier and smaller (0.2 g) than any other salmonid following a two-stage salinity tolerance process initiated around yolk-sac absorption and completed with seawater entry. For the first time, this two-stage ontogeny of salinity tolerance was characterized by either holding posthatch pink salmon in fresh water or transferring them to seawater every 2 weeks. A window of salinity tolerance around yolk-sac absorption was evidenced by a period of zero morbidity in seawater compared with 100% morbidity for newly hatched alevins and 25% morbidity for fry (∼0.2–0.3 g). Increased hypo-osmoregulatory ability at the time of yolk-sac absorption was indicated in fish held in fresh water under constant photoperiod (12 h light : 12 h dark) and temperature (5 °C) by a switch from catabolic to anabolic growth, increased gill Na+K+-ATPase activity and α-1b/α-1a isoform expression, and a plateau in whole-body water content, implying that pink salmon go through a form of smoltification. A large increase in whole-body [Na+] observed in fresh water at yolk-sac absorption may represent a unique strategy for maintaining water balance once fish enter seawater.

Sea lice infection of juvenile pink salmon (Oncorhynchus gorbuscha): effects on swimming performance and postexercise ion balance

2011 ◽  
Vol 68 (2) ◽  
pp. 241-249 ◽  
Author(s):  
L. Nendick ◽  
M. Sackville ◽  
S. Tang ◽  
C. J. Brauner ◽  
A. P. Farrell
Keyword(s):  
Swimming Performance ◽  
Life Stage ◽  
Pink Salmon ◽  
Infection Intensity ◽  
Sea Lice ◽  
Whole Body ◽  
Oncorhynchus Gorbuscha ◽  
Swimming Velocity ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Average Body Mass

Sea lice ( Lepeophtheirus salmonis ) infection negatively affected swimming performance and postswim body ion concentrations of juvenile pink salmon ( Oncorhynchus gorbuscha ) at a 0.34 g average body mass but not at 1.1 g. Maximum swimming velocity (Umax) was measured on over 350 individual pink salmon (0.2–3.0 g), two-thirds of which had a sea lice infection varying in intensity (one to three sea lice per fish) and life stage (chalimus 1 to preadult). For fish averaging 0.34 g (caught in a nearby river free of sea lice and transferred to seawater before being experimentally infected), the significant reduction in Umax was dependent on sea lice life stage, not intensity, and Umax decreased only after the chalimus 2 life stage. Experimental infections also significantly elevated postswim whole body concentrations of sodium (by 23%–28%) and chloride (by 22%–32%), but independent of sea lice developmental stage or infection intensity. For fish averaging 1.1 g (captured in seawater with existing sea lice), the presence of sea lice had no significant effect on either Umax or postswim whole body ions. Thus, a single L. salmonis impacted swimming performance and postswim whole body ions of only the smallest pink salmon and with a sea louse stage of chalimus 3 or greater.

Growth and ionoregulatory ontogeny of wild and hatchery-raised juvenile pink salmon (Oncorhynchus gorbuscha)

2009 ◽  
Vol 87 (3) ◽  
pp. 221-228 ◽  
Author(s):  
A. Grant ◽  
M. Gardner ◽  
L. Nendick ◽  
M. Sackville ◽  
A. P. Farrell ◽  
...  
Keyword(s):  
Specific Growth ◽  
Pink Salmon ◽  
Sea Lice ◽  
Whole Body ◽  
Oncorhynchus Gorbuscha ◽  
Life History Stage ◽  
Initial Exposure ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Future Studies ◽  
Specific Growth Rates

Juvenile pink salmon ( Oncorhynchus gorbuscha (Walbaum, 1792)) enter seawater (SW) shortly following emergence. Little is known about growth and development during this life-history stage when sensitivity to sea louse exposure may be high, an issue that is of current concern in British Columbia. We tested the hypothesis that growth and ionoregulatory development were similar in hatchery-raised (Quinsam) and wild (Glendale and One’s Point) juvenile pink salmon (measured over 22 weeks) following SW entry. Fish body mass increased from 0.20 ± 0.01 to 6.47 ± 0.37 g, with mean specific growth rates of 2.74% to 3.05% body mass·day–1 among the three groups. In all three groups, gill Na+–K+-ATPase (NKA) activity peaked at 12 µmol ADP·mg protein–1·h–1 following 8 weeks post-transfer to SW. Whole body Na+ and Cl– concentrations, which again did not differ among groups, were highest upon initial exposure to SW (~70 mmol·kg wet mass–1) and declined over time as gill NKA activity increased, indicating that the hypo-osmoregulatory capacity was not fully developed following emergence and initial entry into SW. Thus, consistent with our hypothesis, few differences were observed between hatchery-raised and wild juvenile pink salmon reared under laboratory conditions. These baseline data may be important for future studies in determining the effects of sea lice on wild juvenile pink salmon.

THE EFFECT OF PRUDHOE BAY CRUDE OIL ON SURVIVAL AND GROWTH OF EGGS, ALEVINS, AND FRY OF PINK SALMON, ONCORHYNCHUS GORBUSCHA

1975 ◽  
Vol 1975 (1) ◽  
pp. 503-507 ◽  
Author(s):  
Stanley D. Rice ◽  
D. Adam Moles ◽  
Jeffrey W. Short
Keyword(s):  
Fresh Water ◽  
Oil Pollution ◽  
Life Stage ◽  
Pink Salmon ◽  
Water Soluble ◽  
Subsurface Water ◽  
Oncorhynchus Gorbuscha ◽  
Life Stages ◽  
Infrared Spectrophotometry ◽  
Pink Salmon Oncorhynchus Gorbuscha

ABSTRACT Standard 96-hour bioassays with “total” oil solutions in fresh water and seawater determined differences in sensitivity of the developing life stages of pink salmon (Oncorhynchus gorbuscha). Eggs were the most resistant and emergent fry (yolk sac absorbed) the most sensitive to acute 4-day exposures. In fresh water, the 96-hour median tolerance limit (TLm) of fry was 0.4 ml oil/liter mixed mechanically (12 ppm as measured in subsurface water by infrared spectrophotometry). In seawater, it was 0.04 ml oil/liter mixed mechanically (6 ppm as measured in subsurface water by infrared spectrophotometry). Three life stages of alevins were exposed to 10-day sublethal exposures of the water-soluble fraction to determine what doses might affect growth. Growth was affected most severely in alevins exposed during later developmental stages. Decreased growth was observed in fry after 10-day exposures at the lowest dose tested–0.015 ml oil/liter mixed by water agitation (0.73 ppm in subsurface water by infrared spectrophotometry–less than 10% of the 96-hour TLm limit for that life stage). In fresh water, susceptibility of early life history stages of pink salmon to oil pollution is great at the time of emergence (completion of yolk absorption). Susceptibility is even greater in seawater after fry migration.

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