Big Fish Stories: Analysis of Historical Newspaper Data on Size of Lake Sturgeon (Acipenser fulvescens) in the Lake Michigan Basin

2015 ◽  
Vol 42 (1) ◽  
pp. 26-39
Author(s):  
PHILIP COCHRAN

ABSTRACT Old newspapers (1850–1915) in the Lake Michigan basin were surveyed for reports of large lake sturgeon (≥ 100 pounds = 45.4 kg). Records of large fish were obtained from throughout the basin. To assess the accuracy of reported measurements, reported weights associated with reported lengths were compared to weights predicted by a weight-length regression developed for a large sample of fish from Lake Winnebago. Although there were a few obvious or likely outliers in the historical Lake Michigan data set, reported and predicted weights were not significantly different. Moreover, although the mean magnitude of deviations between reported and predicted weights, expressed as a proportion of predicted weight, was substantial, it was comparable to natural variability among lake sturgeon due to the effects of differences between sexes, locations, times of year, and reproductive status.

1992 ◽  
Vol 49 (7) ◽  
pp. 1336-1342 ◽  
Author(s):  
Sylvie Guénette ◽  
Daniel Goyette ◽  
Réjean Fortin ◽  
Jean Leclerc ◽  
Nelson Fournier ◽  
...  

Measurements of annual increments on cross-sections of the first ray of the pectoral fin of 125 St. Lawrence River female lake sturgeon (Acipenser fulvescens) aged 24 yr and older were used to test the correspondance between growth patterns at the margin of the sections and the state of maturity of the fish. For each of the 21 females aged 34 yr and older, and for the upper Ottawa River specimens presented by Roussow (1957. J. Fish. Res. Board Can. 14: 553–572), annual increments were treated as a temporal series and analysed with the contingency periodogram. The mean age at first spawning was determined using the age at the end of the first belt of crowded annuli, following Roussow. Only 3 of the 21 females aged 34 yr and older showed a typical succession of belts of large and narrow annuli. The most frequent periods were 5–11 yr, using the periodogram, as compared with 6–9 yr for Roussow' specimens. No significant correspondance was found between the pattern of the last five annual increments and the state of maturity. The mean age at first spawning, estimated at 19 yr by this technique, is lower than the mean age of sexual maturity determined for St. Lawrence River females based on the examination of the gonads (26 yr).


2020 ◽  
Vol 36 (5) ◽  
pp. 547-558
Author(s):  
Brandon S. Harris ◽  
Carl R. Ruetz ◽  
Travis J. Ellens ◽  
Anthony D. Weinke ◽  
Bopaiah A. Biddanda

2017 ◽  
Vol 33 (3) ◽  
pp. 338-346 ◽  
Author(s):  
B. S. Harris ◽  
C. R. Ruetz ◽  
A. C. Wieten ◽  
M. E. Altenritter ◽  
K. M. Smith

Author(s):  
Ian W. Housman ◽  
Mark D. Nelson ◽  
Charles H. Perry ◽  
Kirk M. Stueve ◽  
Chengquan Huang

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.


2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Chao Xiong ◽  
Claudia Stolle ◽  
Patrick Alken ◽  
Jan Rauberg

Abstract In this study, we have derived field-aligned currents (FACs) from magnetometers onboard the Defense Meteorological Satellite Project (DMSP) satellites. The magnetic latitude versus local time distribution of FACs from DMSP shows comparable dependences with previous findings on the intensity and orientation of interplanetary magnetic field (IMF) By and Bz components, which confirms the reliability of DMSP FAC data set. With simultaneous measurements of precipitating particles from DMSP, we further investigate the relation between large-scale FACs and precipitating particles. Our result shows that precipitation electron and ion fluxes both increase in magnitude and extend to lower latitude for enhanced southward IMF Bz, which is similar to the behavior of FACs. Under weak northward and southward Bz conditions, the locations of the R2 current maxima, at both dusk and dawn sides and in both hemispheres, are found to be close to the maxima of the particle energy fluxes; while for the same IMF conditions, R1 currents are displaced further to the respective particle flux peaks. Largest displacement (about 3.5°) is found between the downward R1 current and ion flux peak at the dawn side. Our results suggest that there exists systematic differences in locations of electron/ion precipitation and large-scale upward/downward FACs. As outlined by the statistical mean of these two parameters, the FAC peaks enclose the particle energy flux peaks in an auroral band at both dusk and dawn sides. Our comparisons also found that particle precipitation at dawn and dusk and in both hemispheres maximizes near the mean R2 current peaks. The particle precipitation flux maxima closer to the R1 current peaks are lower in magnitude. This is opposite to the known feature that R1 currents are on average stronger than R2 currents.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Sidney R. Lehky ◽  
Keiji Tanaka ◽  
Anne B. Sereno

AbstractWhen measuring sparseness in neural populations as an indicator of efficient coding, an implicit assumption is that each stimulus activates a different random set of neurons. In other words, population responses to different stimuli are, on average, uncorrelated. Here we examine neurophysiological data from four lobes of macaque monkey cortex, including V1, V2, MT, anterior inferotemporal cortex, lateral intraparietal cortex, the frontal eye fields, and perirhinal cortex, to determine how correlated population responses are. We call the mean correlation the pseudosparseness index, because high pseudosparseness can mimic statistical properties of sparseness without being authentically sparse. In every data set we find high levels of pseudosparseness ranging from 0.59–0.98, substantially greater than the value of 0.00 for authentic sparseness. This was true for synthetic and natural stimuli, as well as for single-electrode and multielectrode data. A model indicates that a key variable producing high pseudosparseness is the standard deviation of spontaneous activity across the population. Consistently high values of pseudosparseness in the data demand reconsideration of the sparse coding literature as well as consideration of the degree to which authentic sparseness provides a useful framework for understanding neural coding in the cortex.


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