A Revised Interpretation of the History of the Skeena River Sockeye Salmon (Oncorhynchus nerka)

1975 ◽  
Vol 32 (8) ◽  
pp. 1369-1381 ◽  
Author(s):  
W. E. Ricker ◽  
H. D. Smith
Keyword(s):  
Sockeye Salmon ◽  
Maximum Sustainable Yield ◽  
The Other ◽  
Sustainable Yield ◽  
Optimum Level ◽  
Rock Slide ◽  
Recent Period ◽  
Potential Productivity ◽  
History Of ◽  
Skeena River

Three factors are examined as an aid to interpreting the historical sequence of Skeena sockeye catches. One of these (Exploitation Mechanism 1) affects the catch directly, the other two affect catch by way of increasing or decreasing the recruitment produced by a given number of spawners. "Exploitation Mechanism 1" of Ricker (1973) makes the catch taken from any given brood during a time of increasing rate of exploitation greater than when exploitation is steady or decreasing; this is the main reason for excellent catches from 1905 to 1925. "Exploitation Mechanism 2" makes the progeny of any given number of spawners less numerous under conditions of maximum sustainable yield than during the period when rate of utilization is increasing; as a result recruitments observed prior to 1930 overestimate the potential productivity of the system and hence the sustainable yield. Mechanisms 1 and 2 are both operative even if the best rate of exploitation is never exceeded. In fact, however, the rate of exploitation began to exceed the optimum level of 50–55% about 1908, continued to increase until 1928, and then slowly decreased until the optimum level was reached about 1945; during the latter period, and for about 15 yr subsequently, catches were further depressed as spawning stocks were slowly rebuilt. Another factor affecting recruitment is the apparent existence of interaction between neighboring year-classes in respect to survival rate. Although the exact mechanism of this interaction is not yet known, it has produced three sequences of moderately "dominant" year-classes, the most recent being 1959–63–67–71, in spite of the complication of having two important ages of maturity for Skeena sockeye. More important is the fact that during the recent period large spawnings (0.75–1 million) have produced poor returns while moderately small spawnings (0.25–0.5 million) have produced larger year-classes than they did at any earlier period — in spite of the handicap of Mechanism 2. This apparent interaction between broods implies that one or more small spawnings are a necessary prerequisite for unusually successful reproduction by a later large one, and that successful large spawnings depress the reproduction of subsequent smaller ones. When all these factors are considered together, the observed trend of the Skeena catches can be reproduced. Maximum natural sustainable yield from the system would have been achieved about 1960 except for 2 yr of much reduced reproduction caused by the Babine River rock slide of 1951. Currently, the increased numbers of fry produced in artificial spawning channels at Babine Lake have contributed to large smolt runs that are now beginning to appear in the adult catches.

The Skeena River Salmon Fishery, with Special Reference to Sockeye Salmon

1955 ◽  
Vol 12 (3) ◽  
pp. 451-485 ◽  
Author(s):  
D. J. Milne
Keyword(s):  
Special Reference ◽  
Sockeye Salmon ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Relative Size ◽  
Accurate Data ◽  
Gill Net ◽  
History Of ◽  
Skeena River ◽  
Salmon Fishery

The general history of the Skeena River commercial salmon fishery is presented from 1877 to 1948. The changes in fishing areas, seasons and fishing methods are described, together with the trends in the catches obtained. The most accurate data pertain to the important sockeye salmon gill-net fishery. The sockeye catch attained a maximum of 187,000 cases in 1910 and since then has declined to a minimum of 28,000 cases in 1933 and 1943. In recent years the catches have tended to level off. The pink salmon catches declined markedly after 1930. The chum catches also appear to have declined in recent years. Whether or not the spring and coho salmon catches have declined is not known. The size of the sockeye catch appears to be the best available measure of the relative size of the population. An analysis of the age cycles in the catch of sockeye and pink salmon did not reveal a practical basis for prediction. Some possible changes in the fishing regulations are discussed and the need for more data on the fluctuations in the size of the stocks during the fresh water phase is stressed.

scholarly journals Future for Whales

Oryx ◽  
1974 ◽  
Vol 12 (5) ◽  
pp. 532-534
Author(s):  
Richard Fitter
Keyword(s):  
Maximum Sustainable Yield ◽  
The Other ◽  
Sustainable Yield ◽  
Sperm Whales ◽  
Annual Increment ◽  
Fin Whale ◽  
International Whaling Commission

Pie still remains in the sky as far as the hard-pressed fin whale is concerned, following the 26th meeting of the International Whaling Commission in London in June. But the sky has got perceptibly nearer. After the 1973 IWC meeting fin whaling stood to end in 1976; now it should end in 1975—provided the outcome of an Australian resolution is not denounced by Japan and Russia under the 90-day rule that makes the IWC so ineffective. The Australian resolution provided for a total moratorium on all protection stocks, defined as stocks whose annual increment does not maintain the population, so that the fin whale seems bound to be included. The other whales currently being hunted, the sei, minke and sperm whales, are still within the maximum sustainable yield, but there is every reason to fear that, if whaling continues, they too will have to be classed as protection stocks.

Skeena River Sockeye Escapement and Distribution

1952 ◽  
Vol 8c (7) ◽  
pp. 453-468 ◽  
Author(s):  
J. R. Brett
Keyword(s):  
Sockeye Salmon ◽  
River System ◽  
The Other ◽  
Population Estimates ◽  
Commercial Fishery ◽  
Actual Number ◽  
Spawning Areas ◽  
Skeena River ◽  
Best Estimates ◽  
Spawning Streams

Population estimates made from observations on the number of sockeye salmon in the various spawning streams of the Skeena River, B.C., during the period 1944–48 are presented. The methods used include a fence count at Babine Lake, the most important spawing area, supplemented by stream counting in the other areas and sample tagging at Lakelse. Estimates made at Babine by the latter methods were compared with the fence counts; the stream count estimates were about one-third of the actual number present, whereas estimates from tagging were about twice the actual.A brief description of the spawning streams of the Skeena is accompanied by a map showing their location. Best estimates of 1946–47 escapements to major spawning areas are: Babine, 480,000; Morice, 70,000; Bear, 42,000; Lakelse, 29,000. These comprise 92 per cent of the total for the river system. The area of the spawning beds used by sockeye in the system is about 100 acres, or of the order of 1.5 square yards per spawning pair. The division of the whole run is approximately 45 per cent to the commercial fishery, 6 per cent to the Indian fishery, and 49 per cent escapement.

Experimental Harvest Policies for a Mixed-Stock Fishery: Fraser River Sockeye Salmon, Oncorhynchus nerka

1990 ◽  
Vol 47 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Jeremy S. Collie ◽  
Randall M. Peterman ◽  
Carl J. Walters
Keyword(s):  
Regression Model ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fraser River ◽  
Harvest Rate ◽  
Ricker Model ◽  
Exploitation Rate ◽  
Mixed Stock

We investigated harvest strategies aimed at rebuilding the less abundant stocks of Fraser River sockeye salmon, Oncorhynchus nerka. Monte Carlo simulations were run to estimate catch under four different harvest policy designs and three alternative parameterizations of the Ricker model. A pooled regression model was fit to 34 yr of spawner–recruit data from the 10 major stocks of Fraser sockeye. Compared with estimating separate parameters for each stock, the pooled regression model resulted in a more precise estimate of the Ricker a parameter (productivity at low stock sizes). Exploitation rate for maximum sustainable yield depends only on the a parameter and is thus well defined by the pooled regression even though the corresponding optimal escapement levels remain uncertain. A reduction in harvest rates to 70% from the current average 80% increased the simulated 40-yr catch by 31%. More extreme harvest-rate reductions, involving 50% exploitation rates on some stocks for four generations, allowed faster rebuilding and further increases in catch. Extreme harvest-rate reductions were necessary to obtain a 0.5 or greater probability of correctly detecting increased escapements, should the less-abundant runs increase as expected.

scholarly journals POTENTIAL PRODUCTION OF DEMERSAL FISH STOCK IN THE MALACCA STRAIT OF INDONESIA

2015 ◽  
Vol 21 (1) ◽  
pp. 45 ◽  
Author(s):  
Purwanto Purwanto
Keyword(s):  
Demersal Fish ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Fish Stock ◽  
Sustainable Yield ◽  
Optimum Level ◽  
Fish Production ◽  
Potential Production ◽  
Malacca Strait

Malacca Strait is one of the main fishing areas for demersal fishery in Indonesia. To support the management of that fishery, an assessment of the demersal fish stock was conducted. This study estimated that the maximum sustainable yield and the optimal catch per unit effortof demersal fishery in the Malacca Strait were about 106.8 thousand tons/year and 28.5 tons per unit of Danish seine, respectively, resulting from the operation of 3,752 Danish seines. Unfortunately, fishing effort was higher than its optimum level and the fish stock was over-exploited since 2003. To recover the demersal fish stock to its optimum level and to ensure the optimal fish production from demersal fishery in the Malacca Strait, it was necessary to reduce fishing effort at about 67% from its level in 2011.

Fishery ecology and oceanography of the prawn Penaeus merguiensis (de Man) in the Gulf of Papua: estimation of maximum sustainable yield and modelling of yield, effort and rainfall

1997 ◽  
Vol 48 (3) ◽  
pp. 219 ◽  
Author(s):  
C. R. Evans ◽  
L. J. Opnai ◽  
B. D. Kare
Keyword(s):  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Optimum Level ◽  
Total Rainfall ◽  
Real Effort ◽  
Low Levels ◽  
Gulf Of Papua ◽  
De Man ◽  
Penaeus Merguiensis

Annual fishing effort for banana prawns, Penaeus merguiensis (de Man), in the Gulf of Papua increased from low levels in 1974 to around the optimum level in 1978 and peaked at 95000 trawl-hours in 1989 before decreasing after the introduction of effort controls in 1988. Maximum sustainable yield of P. merguiensis was estimated at 559 ± s.e. 25 t (of tails) by linear regression of CPUE (U) on effort using the Schaeffer model. Optimum effort was estimated at 84·0 (± s.e. 11·8) 103 trawl-hours, and an equation for the yield (CE) for a given effort (E) was derived as CE = 13·5E – (8·31 10-2)E2. Application of the CLIMPROD program to Gulf of Papua yield and effort and seasonal rainfall inputs resulted in validated modelling of the fishery. CLIMPROD selected a Schaeffer model for the CPUE–effort relationship (U = a + bE). When CLIMPROD incorporated rainfall (V), the model used was = UaV(b+c) + dV(2b)E (linear–exponential–exponential), where rainfall influences abundance and catchability. For 1974–93 overall, effort was by far the chief determinant of yield. The model using regionally averaged total rainfall in the fourth quarter and unstandardized effort data explained only an extra 5% of the variation in the following year’s catch over the model using effort alone. Standardization of effort data by 3% probably approximates the real effort applied more accurately than does recorded effort.

scholarly journals Interests and Priorities in Sockeye Salmon Management: How are Policies Enacted and Interpreted on three Alaskan Rivers?

2020 ◽  
Author(s):  
◽  
Jake Palazzi
Keyword(s):  
Public Participation ◽  
Public Interest ◽  
Sockeye Salmon ◽  
Maximum Sustainable Yield ◽  
Vulnerable Groups ◽  
Sustainable Yield ◽  
Management Effectiveness ◽  
State Manager ◽  
Native Alaskan ◽  
Insight Into

The large export abundance of Alaskan salmon is well documented, and many studies have been performed to assess the economic and environmental viability of the industry and its management. Less research has been done to characterize how state intentions regarding fisheries allocation are conceived of by management or perceived by vulnerable groups in the user pool. This study seeks to qualitatively characterize the disconnect between state and Native Alaskan perceptions of management effectiveness, public interest, and Native Alaskan involvement using interviews. Results showed that Native Alaskan and state manager respondents had very different perceptions of management effectiveness and equity. When asked questions about the goals of policy and public participation in it, Native Alaskan respondents tended to identify issues of over-commercialized fishing and a lack of direct state acknowledgement of tribes while managers repeatedly referenced an equal public voice for all users and a focus on maximum sustainable yield. Results provide insight into the context certain policy decisions by the state of Alaska are received by Native Alaskan groups.

Analysis of Open-Access Commercial Exploitation and Maximum Economic Yield in Biologically and Technologically Interdependent Fisheries

1975 ◽  
Vol 32 (10) ◽  
pp. 1825-1842 ◽  
Author(s):  
Lee G. Anderson
Keyword(s):  
Open Access ◽  
Graphical Analysis ◽  
Maximum Sustainable Yield ◽  
The Other ◽  
Sustainable Yield ◽  
Commercial Exploitation ◽  
Maximum Economic Yield ◽  
Biological Relationships

Fisheries may be interdependent because of biological relationships that exist between their stocks or because the gear of one affects mortality in the stock of the other. The problems of defining a maximum sustainable yield in these cases are discussed. A graphical analysis is used to describe the combinations of effort from both fisheries where concurrent exploitation is possible and which of these combinations will result in a simultaneous equilibrium. Finally the conditions for a combined maximum economic yield (MEY) are presented and it is shown that they will not hold if each fishery is managed to obtain an individual MEY.

Does more fish mean more money? Evaluating alternative escapement goals in the Bristol Bay salmon fishery

2019 ◽  
Vol 76 (1) ◽  
pp. 153-167 ◽  
Author(s):  
Jocelyn Yun-Ling Wang ◽  
Christopher M. Anderson ◽  
Curry J. Cunningham ◽  
Ray Hilborn ◽  
Michael R. Link
Keyword(s):  
Management Strategy ◽  
Sockeye Salmon ◽  
High Volume ◽  
Maximum Sustainable Yield ◽  
Processing Capacity ◽  
Sustainable Yield ◽  
Lower Margin ◽  
Bristol Bay ◽  
Strategy Evaluation ◽  
Salmon Fishery

We develop an economically sophisticated management strategy evaluation for four sockeye salmon (Onchorhynchus nerka) fishing districts in Bristol Bay, Alaska, to evaluate whether proposed increases in escapement goals — the number of fish allowed up each river to spawn — could improve fishery outcomes for the industry and the region. Higher escapements increase average runs toward biological maximum sustainable yield, but this is driven by infrequent years of very abundant runs. Our economic model shows processors do not add capacity in response to infrequent abundant runs. Therefore, interannual variance in district-specific catch increases because years with little or no fishing become more frequent to meet higher escapement in low-run years, but industry cannot capture greater value in the high-run years. In abundant runs, processors shift available labor to focus on high-volume, lower-margin products; in very abundant years, insufficient processing capacity allows additional fish to escape. Mobile driftnet vessels that can move to rivers experiencing high runs each year benefit, but district specialists in the small boat and set-net fleets are more vulnerable to years with little or no catch.

Theodor W. Adorno

2018 ◽  
Author(s):  
Colby Dickinson
Keyword(s):  
The Other ◽  
History Of Thought ◽  
History Of ◽  
The One

In his somewhat controversial book Remnants of Auschwitz, Agamben makes brief reference to Theodor Adorno’s apparently contradictory remarks on perceptions of death post-Auschwitz, positions that Adorno had taken concerning Nazi genocidal actions that had seemed also to reflect something horribly errant in the history of thought itself. There was within such murderous acts, he had claimed, a particular degradation of death itself, a perpetration of our humanity bound in some way to affect our perception of reason itself. The contradictions regarding Auschwitz that Agamben senses to be latent within Adorno’s remarks involve the intuition ‘on the one hand, of having realized the unconditional triumph of death against life; on the other, of having degraded and debased death. Neither of these charges – perhaps like every charge, which is always a genuinely legal gesture – succeed in exhausting Auschwitz’s offense, in defining its case in point’ (RA 81). And this is the stance that Agamben wishes to hammer home quite emphatically vis-à-vis Adorno’s limitations, ones that, I would only add, seem to linger within Agamben’s own formulations in ways that he has still not come to reckon with entirely: ‘This oscillation’, he affirms, ‘betrays reason’s incapacity to identify the specific crime of Auschwitz with certainty’ (RA 81).

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