Modelling the effects of variation in growth, recruitment, and harvest on lake sturgeon population viability and recovery

Author(s):  
Patrick A. Nelson ◽  
Craig A. McDougall ◽  
Marten A. Koops ◽  
Cameron C. Barth
2011 ◽  
Author(s):  
J. M. Scott ◽  
Edward O. Garton ◽  
Brian Dennis ◽  
Jon S. Horne ◽  
Dale Goble ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yashuai Zhang ◽  
Fang Wang ◽  
Zhenxia Cui ◽  
Min Li ◽  
Xia Li ◽  
...  

Abstract Background One of the most challenging tasks in wildlife conservation and management is clarifying which and how external and intrinsic factors influence wildlife demography and long-term viability. The wild population of the Crested Ibis (Nipponia nippon) has recovered to approximately 4400, and several reintroduction programs have been carried out in China, Japan and Korea. Population viability analysis on this endangered species has been limited to the wild population, showing that the long-term population growth is restricted by the carrying capacity and inbreeding. However, gaps in knowledge of the viability of the reintroduced population and its drivers in the release environment impede the identification of the most effective population-level priorities for aiding in species recovery. Methods The field monitoring data were collected from a reintroduced Crested Ibis population in Ningshan, China from 2007 to 2018. An individual-based VORTEX model (Version 10.3.5.0) was used to predict the future viability of the reintroduced population by incorporating adaptive patterns of ibis movement in relation to catastrophe frequency, mortality and sex ratio. Results The reintroduced population in Ningshan County is unlikely to go extinct in the next 50 years. The population size was estimated to be 367, and the population genetic diversity was estimated to be 0.97. Sensitivity analysis showed that population size and extinction probability were dependent on the carrying capacity and sex ratio. The carrying capacity is the main factor accounting for the population size and genetic diversity, while the sex ratio is the primary factor responsible for the population growth trend. Conclusions A viable population of the Crested Ibis can be established according to population viability analysis. Based on our results, conservation management should prioritize a balanced sex ratio, high-quality habitat and low mortality.


Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1419
Author(s):  
Janet Genz ◽  
Rachael Hicks

In fishes, environmental ion availability can have substantial effects on growth and development. This study examined the development of Lake Sturgeon in response to the varying environmental ion availability that they experience as part of a conservation stocking program. We reared sturgeon in natural water from the Coosa River, which had higher concentrations of Mg2+, Na+, and Zn2+ than standard hatchery conditions, while [Ca2+] at the Warm Springs National Fish Hatchery was 2× higher than in the Coosa River. Eggs were hatched in each water type and the larvae were sampled at time points before and after yolk absorption during the first 8 weeks of development. Total length and weight in WSNFH larvae were significantly higher than larvae in Coosa River water starting at 8 dph, indicating that growth was dependent on the different environmental ion levels. Concentrations of the ions of interest were also determined for whole-body acid digests of the exposed Lake Sturgeon. We found that Lake Sturgeon reared in Coosa River water had significantly higher magnesium and zinc than Lake Sturgeon reared in WSNFH water (p < 0.05), while calcium was significantly higher in WSNFH than Coosa River water. This difference shows that different environmental ion concentrations also impact the overall development of larval Lake Sturgeon.


2021 ◽  
Author(s):  
Naomi L. Indigo ◽  
Chris J. Jolly ◽  
Ella Kelly ◽  
James Smith ◽  
Jonathan K. Webb ◽  
...  

1952 ◽  
Vol 30 (6) ◽  
pp. 561-570
Author(s):  
J. G. Aldous ◽  
D. K. R. Stewart

Suspensions of the cells of baker’s yeast were irradiated with ultraviolet light for sufficient times to produce populations of 75, 50, 30, and 5% viable cells. After washing and drying, various enzyme solutions were prepared from these cells. Enzymatic activities, on a nitrogen basis, were compared to those of solutions prepared from a nonirradiated population. At the 50% survival level, hexokinase, carboxylase, and zymase were inhibited to a degree roughly proportional to the viability. Carboxylase, and to a certain extent, hexokinase activity varied directly as the population viability. Catalase, alcohol dehydrogenase, and lactic dehydrogenase showed no diminution in activity even at the 5% survival level. These results suggest that although ultraviolet radiation may produce nuclear damage, the primary site of action may be certain enzymes of the cytoplasm.


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