Use of the stratified-Petersen estimator in fisheries management: estimating the number of pink salmon (Oncorhynchus gorbuscha) spawners in the Fraser River

1998 ◽  
Vol 55 (2) ◽  
pp. 281-296 ◽  
Author(s):  
Carl James Schwarz ◽  
Carolyn Gail Taylor

The simple-Petersen estimator is a well-known mark-recapture method to estimate animal abundance. Two key assumptions are equal catchability in both samples and complete mixing of tagged and untagged animals. If these are violated, severe bias can occur. The stratified-Petersen estimator can be used to account for some of the heterogeneity in catchability or mixing. In this paper, we first review recent developments in the stratified-Petersen experiment for fisheries audiences and demonstrate some of the practical problems that can occur that have not been discussed in the theoretical literature. Second, we present a case study to estimate the gross escapement of Fraser River pink salmon (Oncorhynchus gorbuscha) in 1991. The motivation for this study is a discrepancy of over 5 million fish between the estimates as derived by the Pacific Salmon Commission (PSC) (7.5 million fish based on a hydroacoustic method) and the Department of Fisheries and Oceans (DFO), Canada (13.0 million fish based on a mark-recapture method). One hypothesis put forward was that the discrepancy may be due to the use of a pooled-Petersen estimator when there is differential migration over time. The stratified-Petersen model suggests that little of this discrepancy can be explained by differential migration.

1938 ◽  
Vol 4a (2) ◽  
pp. 141-150 ◽  
Author(s):  
A. L. Pritchard

In 1931, 1933, 1935, odd-numbered years, when no natural runs of pink salmon (Oncorhynchus gorbuscha) occur in the Masset area, British Columbia, transfers of eggs were made from the Tlell river on the east coast of Graham island to McClinton creek, a tributary of Masset inlet. The following free-swimming fry were released: from the 1931 experiment—753,646 normal and 124,002 "marked" by the removal of the adipose and left ventral fins, and from that of 1935—397,657 normal and 108,200 "marked" by the removal of the adipose and right ventral fins. From the former, 40 "marked" adults were recovered in the Fraser river fishery in 1933, and from the latter four "marked" adults at McClinton creek in 1937. In the 1933 experiment 540,294 eyed eggs were planted but these were destroyed by freshets the following winter. Possible reasons for the failure of these experiments and the absolute blank in the "off" years are suggested.


1973 ◽  
Vol 30 (9) ◽  
pp. 1309-1316 ◽  
Author(s):  
A. B. Stasko ◽  
R. M. Horrall ◽  
A. D. Hasler ◽  
D. Stasko

Eleven mature pink salmon (Oncorhynchus gorbuscha) were tracked in September 1967 for periods of 3–50 hr over distances from 2 to 127 km to determine migration patterns.The fish were classified as "active" or "passive." Active fish moved faster and their paths were straighter. Active tracks ended distant from and to the north (toward the Fraser River) of the release point; passive tracks ended near or south of the release point. Active fish did not follow shorelines, but travelled primarily along the axes of tidal currents. They moved both with the northward flood and against the southward ebb currents, during day and at night. Average ground speed of active fish was 62 cm/sec (2.2 km/hr).


1979 ◽  
Vol 36 (10) ◽  
pp. 1283-1287 ◽  
Author(s):  
Richard E. Berg

Meristic and morphometric measurements were taken from 33 male and 44 female mature pink salmon, Oncorhynchus gorbuscha, collected in three Lake Superior tributaries in Marquette County, Michigan. Significant sexual differences were found for eight characteristics in males and two in females. The male fish had a greater degree of differentiation in the head and hump regions; females had larger and longer anal fins. The Lake Superior fish were found to have shorter bodies, larger and longer fins, and more exaggerated development in the male head and hump than has been reported for the Pacific populations. Key words: pink salmon, salmonids, exotic species, Lake Superior, morphology


1987 ◽  
Vol 44 (2) ◽  
pp. 348-356 ◽  
Author(s):  
I. V. Williams ◽  
J. R. Brett

Critical swimming speeds were determined for male and female pink salmon (Oncorhynchus gorbuscha) captured from the Fraser and Thompson rivers and Seton Creek, British Columbia. The fish were categorized into two basic groups. Lower river fish were captured from the Fraser River at Fort Langley and Yale, and up-river fish were captured from the Thompson River at the Canyon and at Ashcroft and from Seton Creek near Lillooet, British Columbia. The critical swimming speeds of males and females in various stages of maturation were compared. In general, the up-river fish were stronger swimmers than the lower river fish. Gravid fish were stronger swimmers than spawning fish, which in turn were stronger swimmers than fish which were spawned out. Standardized critical swimming speeds ranged from a mean of 1.73 ± 0.35 (SE) body lengths/s for spawned females up to 3.39 ± 0.48 lengths/s for up-river gravid males.


Author(s):  
Людмила Александровна Лысенко ◽  
Надежда Павловна Канцерова ◽  
Марина Юрьевна Крупнова ◽  
Денис Александрович Ефремов ◽  
Нина Николаевна Немова ◽  
...  

1972 ◽  
Vol 29 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Edward M. Donaldson ◽  
James D. Funk ◽  
F. C. Withler ◽  
R. B. Morley

Sexual maturation in male pink salmon (Oncorhynchus gorbuscha) from Jones Creek, a tributary of the Fraser River, British Columbia, was accelerated by intraperitoneal injections of partially purified chinook salmon (O. tshawytscha) gonadotropin. The treated pinks produced milt 1 year earlier than normal. Milt from these fish was compared with milt from wild Lower Babine River pinks with respect to its ability to fertilize the ova of Lower Babine River females. There were no marked differences in proportions of ova fertilized, in survival to hatching, or in numbers of deformed larvae. Densities of sperm in the milt from treated males ranged from 0.15 × 109 to 7.35 × 109 per ml; sperm densities in the milt from wild males ranged from 19.3 × 109 to 38.6 × 109 per ml. Two stages in testicular development were identified among the treated males and found to be directly related to the success of fertilization. The significance of induced early maturation in attempts to establish pink runs in the "off" year rivers is discussed.


1999 ◽  
Vol 56 (11) ◽  
pp. 2087-2098 ◽  
Author(s):  
I K Birtwell ◽  
R Fink ◽  
D Brand ◽  
R Alexander ◽  
C D McAllister

Saltwater-acclimated, coded-wire tagged, and adipose fin clipped pink salmon (Oncorhynchus gorbuscha) fry were exposed for 10 days to seawater (control) or 25-54 μg·L-1 (low dose) or 178-349 μg·L-1 (high dose) of the water-soluble fraction (WSF) of North Slope crude oil. The WSF was composed primarily of monoaromatics and was acutely lethal to the fry: 96-h LC50 ranged from 1 to 2.8 mg·L-1. After exposure the fry (30 000 per treatment) were released into the Pacific Ocean to complete their life cycle. The experiment was replicated in 1990, 1991, and 1992. There was no consistent significant dose-dependent effect of the 10-day exposure to the crude oil WSF on growth of the pink salmon prior to their release. Adult pink salmon from this experiment were captured in fisheries and also recovered from their natal Quinsam River, British Columbia. Pink salmon from each treatment group were recovered in similar numbers. Exposure of populations of fry to the WSF of crude oil and release to the Pacfic Ocean did not result in a detectable effect on their survival to maturity. Fry from all treatment groups incurred typically high mortality following release, and there were no discernible effects on survival that were attributable to exposure to the WSF of crude oil.


2008 ◽  
Vol 65 (10) ◽  
pp. 2178-2190 ◽  
Author(s):  
Yunbo Xie ◽  
Catherine G.J. Michielsens ◽  
Andrew P. Gray ◽  
Fiona J. Martens ◽  
Jacqueline L. Boffey

Detailed avoidance reactions of adult migrating salmon to a mobile survey vessel were successfully observed with side-looking dual-frequency identification sonar (DIDSON) in the lower Fraser River (British Columbia, Canada). Both adult sockeye ( Oncorhynchus nerka ) and pink salmon ( Oncorhynchus gorbuscha ) returning to the river were found to avoid the approaching vessel by initiating lateral movements away from the vessel, making the fish unlikely to be insonified by the downward-looking transducers towed by the vessel. The vessel was found to have an estimated mean interference range of 4 m from its propeller. Analyses of the data concluded that once the vessel and fish were separated by more than 7 m, the vessel no longer affected the normal migration behaviour of the fish.


1974 ◽  
Vol 31 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
Robert A. Bams

A hatchery method designed for mass production of unfed Pacific salmon fry and utilizing a gravel medium during most of the incubation period is being evaluated on successive cycles of a stock of pink salmon, Oncorhynchus gorbuscha, of the Tsolum River, B.C. Possible treatment effects are studied at emergent fry and returning adult stages in artificially and naturally propagated populations. Average growth rate and, hence, efficiency of yolk conversion were unimpeded in the hatchery environment, but fry emerged 11 days prematurely. Survival from green egg to emergent fry averaged 74.9% in the hatchery and 20.6% in the creek, for a gain ratio at emergence of 3.63. Recovery of selectively marked populations of hatchery and creek fish demonstrated almost identical survival rates from fry to adult stages and a final gain ratio of 3.46. Adult lengths and weights, fecundity, and timing of migrations were unaffected generally by the hatchery treatment.


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