Estimates of stream residence time and escapement based on capture-recapture data

2000 ◽  
Vol 57 (1) ◽  
pp. 241-246 ◽  
Author(s):  
Micheline Manske ◽  
Carl J Schwarz
Keyword(s):  
Residence Time ◽  
Coho Salmon ◽  
Area Under The Curve ◽  
Oncorhynchus Kisutch ◽  
Accurate Estimate ◽  
Small River ◽  
Entire Population ◽  
Residence Times ◽  
Capture Recapture ◽  
Curve Method

The area-under-the-curve method is a widely used method for estimating salmon escapement. The method depends on obtaining an accurate estimate of stream residence time, or stream life. This paper develops an estimator of stream residence time based on capture-recapture data. If the capture-recapture experiment is performed on the entire population, the escapement can also be estimated using the area-under-the-curve method. Simulations showed that the stream residence estimator and the area-under-the-curve estimator provide precise estimates of stream residence and escapement, respectively. These methods were used to estimate the stream residence times and escapements of coho salmon (Oncorhynchus kisutch) in a small river on Vancouver Island in 1989 and 1990.

Estimators of stream residence time of Pacific salmon (Oncorhynchus spp.) based on release-recapture data

1998 ◽  
Vol 55 (12) ◽  
pp. 2580-2587 ◽  
Author(s):  
James M Lady ◽  
John R Skalski
Keyword(s):  
Residence Time ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Area Under The Curve ◽  
Accurate Estimate ◽  
Right Censoring ◽  
Nonparametric Estimator ◽  
Time Estimate ◽  
Wildlife Population ◽  
Curve Method

The area-under-the-curve method is a widely used method for estimating salmon escapement. The method depends on obtaining an accurate estimate of stream residence time, or stream life. This paper develops two estimators of stream residence time based on release-recapture data: a nonparametric estimator and a parametric estimator. Monte Carlo simulations showed that with an adequate release size and number of sampling occasions, both estimators provide precise estimates of stream residence time. If there is significant right censoring, however, the parametric estimator is significantly less biased. If the data are too sparse, the parametric estimator performs poorly and often fails. The stream residence time of spawning sockeye salmon (Oncorhynchus nerka) in Iliamna Lake, Alaska, was estimated using the estimators developed here. Because the estimators also provide the variance of the estimates, the precision of the stream residence time estimate could be assessed, and we were able to test and reject the hypothesis that the stream residence time for females is equal to that of males. Both estimators are applicable to estimating the life expectancy of any fish or wildlife population with release-recapture techniques.

A Robust Procedure for Estimating Salmon Escapement based on the Area-Under-the-Curve Method

1992 ◽  
Vol 49 (10) ◽  
pp. 1982-1989 ◽  
Author(s):  
K. K. English ◽  
R. C. Bocking ◽  
J. R. Irvine
Keyword(s):  
Residence Time ◽  
Theoretical Basis ◽  
Area Under The Curve ◽  
Residence Times ◽  
Survey Area ◽  
Independent Estimate ◽  
Coastal Streams ◽  
Curve Method ◽  
Total Residence Time ◽  
Survey Effort

Salmon spawning escapements are estimated using the area-under-the-curve (AUC) method by dividing the integral of the escapement curve by the average residence time of fish in the survey area. We present two forms of the basic AUC method which differ in the procedure used to estimate residence time from the observations of tagged fish during stream surveys. AUC estimates based on "observed residence times" were sensitive to variability in survey timing, observer efficiency, and tag detection, while those based on "total residence times" were more robust. For two coastal streams, escapement estimates based on "observed residence times" were between 1.1, and 6.8 times larger than an independent escapement estimate (from fence counts and mark–recapture data), while estimates based on "total residence times" were generally closer to the independent estimate (0.74–1.51 times the estimate, and within 26% six times out of seven). The consistency of our results under a wide variety of survey conditions, combined with their strong theoretical basis, indicates that an AUC method based on annual estimates of total residence time and observer efficiency is robust. However, the level of survey effort required for these methods would limit their application to high-priority streams or populations.

Estimating Salmon Spawning Escapement Using Capture–Recapture Methods

1993 ◽  
Vol 50 (6) ◽  
pp. 1181-1197 ◽  
Author(s):  
Carl J. Schwarz ◽  
Richard E. Bailey ◽  
James R. Irvine ◽  
Frank C. Dalziel
Keyword(s):  
Maximum Likelihood ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Maximum Likelihood Estimators ◽  
Small River ◽  
Standard Errors ◽  
Capture Recapture ◽  
Simulation Results ◽  
Biased Estimators

We describe a method of estimating the spawning escapement of coho salmon (Oncorhynchus kisutch) from capture–recapture data. Traditional capture–recapture analyses do not directly provide estimates of escapements; however, we show how simple modifications to the Jolly–Seber method can estimate the total number of fish returning to a river including those that enter and die between sampling occasions. Spawning runs of Pacific salmon were simulated and their escapements estimated using capture–recapture. The performance of the maximum likelihood estimators (MLEs), the censored MLEs, the constrained MLEs, and less-biased estimators in estimating the run sizes and providing estimates of precision were evaluated. Simulation results indicated that constrained MLEs provided the most appropriate estimates of escapement and that standard errors be computed using the large-sample variance formulae evaluated at these estimates. These methods were used to estimate the escapements of coho salmon to a small river on Vancouver Island in 1989 and 1990.

A Fry Trap Method for Estimating Salmonid Survival from Egg Deposition to Fry Emergence

1969 ◽  
Vol 26 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Robert W. Phillips ◽  
K. V. Koski
Keyword(s):  
Dissolved Oxygen ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Field Tests ◽  
Accurate Estimate ◽  
The Past ◽  
Egg Deposition

The method involves a trap of nylon netting placed over an individual redd with the trap's edges buried 15–20 cm in the gravel just outside the periphery of the redd. It has been used successfully on more than 70 coho salmon (Oncorhynchus kisutch) redds over the past 5 years, with as many as 2061 fry being captured from a single redd. The trap is relatively stable because it is flexible and conforms to the surface of the streambed, causing debris to float or roll over the surface. It can be used on individual redds; thus, emergent survival for separate parental combinations can be estimated. Field tests showed the efficiency of the trap approached 100%. Installation and presence of the trap had no significant effect on intragravel dissolved oxygen and gravel permeability. Mortality of fry in the traps averaged less than 1.5% when fry were removed at least three times a week. We concluded that the trap provides a more accurate estimate of survival from egg deposition through fry emergence than four other methods.

scholarly journals Effect of bathymetric changes on residence time in Buenaventura bay (Colombia)

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 241-248
Author(s):  
Francisco Fernando Garcia Renteria ◽  
Mariela Patricia Gonzalez Chirino
Keyword(s):  
Finite Elements ◽  
Residence Time ◽  
Particle Tracking ◽  
Hydrodynamic Model ◽  
Residence Times ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Bathymetric Changes

In order to study the effects of dredging on the residence time of the water in Buenaventura Bay, a 2D finite elements hydrodynamic model was coupled with a particle tracking model. After calibrating and validating the hydrodynamic model, two scenarios that represented the bathymetric changes generated by the dredging process were simulated. The results of the comparison of the simulated scenarios, showed an important reduction in the velocities fields that allow an increase of the residence time up to 12 days in some areas of the bay. In the scenario without dredging, that is, with original bathymetry, residence times of up to 89 days were found.

Induced ovulation in coho salmon (Oncorhynchus kisutch). I. Further studies on the use of salmon pituitary preparations

Aquaculture ◽  
1981 ◽  
Vol 26 (1-2) ◽  
pp. 117-127 ◽  
Author(s):  
George A. Hunter ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Induced Ovulation
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