Vertebral fusions in farmed Chinook salmon ( Oncorhynchus tshawytscha ) in New Zealand

2019 ◽  
Author(s):  
Peter S. Davie ◽  
Seamus P. Walker ◽  
Matthew R. Perrott ◽  
Jane E. Symonds ◽  
Mark Preece ◽  
...  

NIR news ◽  
2018 ◽  
Vol 29 (5) ◽  
pp. 12-14
Author(s):  
Matthew R Miller ◽  
Jonathan Puddick ◽  
Jane E Symonds ◽  
Seumas P Walker ◽  
Hong (Sabrina) Tian

Near infrared spectroscopy has been employed to determine the proximate composition of Chinook salmon ( Oncorhynchus tshawytscha) and Greenshell Mussels™ ( Perna canaliculus). This work was presented at the Australian Near Infrared Spectroscopy Group and New Zealand Near Infrared Spectroscopy Society meeting in Rotorua, 11–12 April 2018, where it won the best overall presentation award for Near Infrared Science (Figure 1).





1997 ◽  
Vol 54 (6) ◽  
pp. 1246-1254 ◽  
Author(s):  
M J Unwin

Fry-to-adult survival rates for chinook salmon (Oncorhynchus tshawytscha) from Glenariffe Stream, a tributary of the Rakaia River, New Zealand, were estimated for fish of both natural and hatchery origin. Survival of naturally produced fry, most of which leave Glenariffe Stream within 24 h of emergence, averaged 0.079% (range 0.013-1.17%). For hatchery fish released at 8-12 months, standardised to a mean weight of 38 g, survival covaried with weight at release consistently across all brood years and averaged 0.34% (range 0.008-3.28%). Survival rates for hatchery fish were four times higher than for naturally produced fry, but were extremely poor relative to their size at release. Survival rates for fish of natural and hatchery origin were positively correlated, suggesting that recruitment of both stocks is primarily controlled by common influences within the marine environment, probably during the first winter at sea. Stock-recruitment analysis for the natural population showed little tendency for recruitment to increase with stock size, suggesting that marine survival rates may be density dependent. Although the reasons for the relatively poor survival of hatchery fish are unclear, the results provide a case study in which hatchery fish appear to have a poorer ``fitness to survive'' than their natural counterparts.





1998 ◽  
Vol 55 (8) ◽  
pp. 1946-1953 ◽  
Author(s):  
Michael T Kinnison ◽  
Martin J Unwin ◽  
William K Hershberger ◽  
Thomas P Quinn

Interpopulation differences in several adult phenotypic traits suggest that New Zealand (NZ) chinook salmon (Oncorhynchus tshawytscha) are evolving into distinct populations. To further investigate this hypothesis, we compared egg sizes, fecundities, and early development rates of chinook from two NZ streams. The two NZ study populations differed in size-adjusted egg weight and gonadosomatic index, but not in size-adjusted fecundity. Egg weight, fecundity, and gonadosomatic index values for both NZ populations were different than values for chinook from Battle Creek, California, the population regarded as the ancestral NZ stock. In contrast, there was little evidence of divergence in juvenile development. Time to hatching did not differ between the two NZ study populations and heritability estimates were small with large standard errors. Evidence of a small difference in alevin growth rate may have represented an effect of yolk conversion mechanics related to egg size. Despite the similarity in development rates under shared conditions, modeling based on temperature records suggests that emergence dates in the two NZ streams may differ by 4-6 weeks, yielding significant phenotypic differences.





2018 ◽  
Vol 42 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Cara L. Brosnahan ◽  
John S. Munday ◽  
Hye Jeong Ha ◽  
Mark Preece ◽  
John B. Jones


1997 ◽  
Vol 54 (6) ◽  
pp. 1235-1245 ◽  
Author(s):  
M J Unwin ◽  
G J Glova

Chinook salmon (Oncorhynchus tshawytscha) spawning runs in Glenariffe Stream, New Zealand, exhibited significant changes in life history traits following supplementation releases of hatchery-reared juveniles. Total run strength did not change but the proportion of naturally produced fish declined to 34%. Attempts to separate spawners of natural and hatchery origin were unsuccessful, and 31-48% of natural spawners are now of hatchery origin. Hatchery males were smaller at age 2 and 3 than males of natural origin, and more often matured as jacks, producing an 86-mm decrease in mean fork length over 28 years. There was no change in length at age or age at maturity for female spawners. The proportion of jacks entering Glenariffe Stream each year was positively correlated with the proportion of jacks in the ensuing cohort. Most differences between fish of natural and hatchery origin were related to hatchery rearing practices, but the decline in age at maturity among naturally produced males appears to reflect traits inherited from parent stock of hatchery origin. Hatchery releases may also favour the survival of ocean-type fry over stream-type fry, possibly reversing a tendency for stream-type behaviour to evolve in response to the lack of estuaries on most New Zealand chinook salmon rivers.



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