An Estimate of Ocean Mortality of Bristol Bay Sockeye Salmon Three Years at Sea

1968 ◽  
Vol 25 (6) ◽  
pp. 1219-1227 ◽  
Author(s):  
Stephen B. Mathews
Keyword(s):  
Mortality Rate ◽  
Freshwater Fish ◽  
Sockeye Salmon ◽  
Population Estimation ◽  
Bristol Bay ◽  
Age Composition ◽  
Dichotomous Population ◽  
Sea Fish ◽  
Annual Mortality ◽  
High Seas

The method of population estimation based on change in composition of a dichotomous population was applied to Bristol Bay sockeye salmon to estimate the mortality rate of 3-ocean (3 years at sea) fish during their final year in the ocean. A difference in freshwater age composition between 1-ocean immatures in 1964 and 2-ocean immatures in 1965 was evident in samples taken in the high seas. This difference was apparently due to a greater tendency of 2-freshwater fish than 1-freshwater fish to mature after 2 years at sea. The known quantities of these two freshwater categories in the mature 2-ocean run of 1965 enabled an estimate of the population of 2-ocean immatures at sea in 1965. From this estimate and the quantity of 3-ocean matures in the 1966 run, the annual mortality rate was estimated to be.42.

A statistical model for in-season forecasts of sockeye salmon (Oncorhynchus nerka) returns to the Bristol Bay districts of Alaska

2005 ◽  
Vol 62 (7) ◽  
pp. 1665-1680 ◽  
Author(s):  
Saang-Yoon Hyun ◽  
Ray Hilborn ◽  
James J Anderson ◽  
Billy Ernst
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Bayesian Probability ◽  
Bristol Bay ◽  
Age Composition ◽  
Information Sets ◽  
Information Set ◽  
Fishery Data ◽  
Highest Posterior Density ◽  
Return Data

We developed a model for in-season age-specific forecasts of salmon returns using preseason return forecasts, age composition of in-season returns, cumulative in-season returns by fishing district, and age composition and an index of abundance from an in-season test fishery. We apply this method to the sockeye salmon (Oncorhynchus nerka) fishery in the Bristol Bay districts of Alaska. The model generates point estimates and Bayesian probability distributions for return numbers by age and river, and it provides an integrated framework for including all of the major data sources currently used in in-season forecasting. We evaluated model performance using early-season data from 1999–2001 and compared the effects of four information sets on forecast accuracy. The four information sets were as follows: I, district-specific inshore return data; II, inshore return data and test fishery data; III, inshore return data and preseason forecasts; IV, inshore return data, test fishery data, and preseason forecasts. Forecasts from information sets II, III, and IV were less biased than those from information set I. However, in terms of the forecast interval, forecasts from information set II were best because the 95% highest posterior density regions of forecasts from information set II covered the actual returns most frequently.

A general model for reconstructing salmon runs

2010 ◽  
Vol 67 (5) ◽  
pp. 886-904 ◽  
Author(s):  
Trevor A. Branch ◽  
Ray Hilborn
Keyword(s):  
General Model ◽  
Sockeye Salmon ◽  
Migration Routes ◽  
Bristol Bay ◽  
Age Composition ◽  
Gear Selectivity ◽  
Alternative Hypotheses ◽  
And Migration ◽  
The Impact ◽  
River Fish

A general model is developed for salmon run reconstruction based on catch, escapement, and age composition data. The model is based on “groups” of salmon, each of which share the same characteristics but can differ from other groups in run timing, abundance, gear selectivity, and migration routes. The model is highly flexible so that it can be adapted to a variety of fisheries and can compare the fits of alternative hypotheses to available data. The model is applied to three sockeye salmon ( Oncorhynchus nerka ) districts in Bristol Bay, Alaska, USA, to show the effect of allowing age classes to arrive at different times and the impact of including process errors to mimic day-to-day arrival variability. The model predicts that in 2005, Wood River salmon comprised only 54% of the catch in the Nushagak fishing district (but 71% of the escapement), although these predictions are contradicted by genetic data for 2006–2008 showing high harvest rates of Wood River and Nushagak River fish but only light harvest rates of Igushik River fish. The genetics highlight the importance of including stock-specific availability parameters in future versions of the model to account for differences in harvest rates among stocks caught in the same fishing district.

Comparison of Ocean Growth and Mortality of Sockeye Salmon During Their Last Two Years

1962 ◽  
Vol 19 (4) ◽  
pp. 531-560 ◽  
Author(s):  
W. E. Ricker
Keyword(s):  
Mortality Rate ◽  
Sockeye Salmon ◽  
Total Yield ◽  
Significant Fraction ◽  
Natural Mortality ◽  
Total Rate ◽  
Growth Types ◽  
Rates Of Growth ◽  
Maximum Estimate ◽  
High Seas

Average instantaneous rates of growth in weight of sockeye (Oncorhynchus nerka) of two stocks are computed for their last two growth-years, from scale measurements by Barnaby and Foerster. Values from 0.081 to 0.156 per month are obtained. These rates greatly exceed a maximum estimate of instantaneous natural mortality rate, 0.038 per month, for the same period. The latter is based on the total rate of ocean mortality of large smolts, divided by the number of months they are at sea. On this basis, oceanic capture of sockeye during the year prior to their maturation yields less than 35% to 50% of the catch that would be taken from the same fish by a shore fishery the following year. Minimum estimates of loss from high-seas capture of major growth types of sockeye during the year of their maturation vary from 6% to nearly 40%, depending on how early in the season the fishing is done and the particular stock involved. While an increase in mortality rate as sockeye approach shore cannot be excluded, any resulting decrease in the estimate of loss among currently-maturing fish must be accompanied by an increase in the estimate of loss from capture in the year before maturity. In any event, a high-seas fishery that takes any significant fraction of non-maturing sockeye must markedly decrease the total yield from the stocks involved.

scholarly journals A general model for salmon run reconstruction that accounts for interception and differences in availability to harvest

2018 ◽  
Vol 75 (3) ◽  
pp. 439-451 ◽  
Author(s):  
Curry J. Cunningham ◽  
Trevor A. Branch ◽  
Tyler H. Dann ◽  
Matt Smith ◽  
James E. Seeb ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Molecular Genetic ◽  
Bristol Bay ◽  
Age Composition ◽  
Genetic Stock ◽  
Genetic Stock Identification ◽  
Reconstruction Methods ◽  
Salmon Fisheries ◽  
Genetic Techniques ◽  
Mixed Stock

Understanding population-specific spawner–recruit relationships is necessary for sustainable salmon management. Where multiple populations are harvested together, run reconstruction methods partition mixed-stock catches and allocate recruits back to their populations of origin. Traditional run reconstruction methods often use age composition data to inform catch partitioning. However age-only methods do not account for stock-specific differences in the availability of fish to harvest within fishing areas or the incidental harvest of nontarget stocks in nearby fishing areas. Advances in molecular genetic techniques permit genetic stock identification (GSI) of both contemporary and historical catch samples. We present a statistical model for salmon run reconstruction that utilizes both age composition and GSI data to estimate differences in the availability of stocks within, and interception rates among, terminal fisheries. When applied to the commercial sockeye salmon (Oncorhynchus nerka) fishery in Bristol Bay, Alaska, new estimates of population productivity differed from those generated using previous age-only methods by 0.1%–155.1%, with stock-specific mean absolute percent differences of 9.7%–38.7% across years, underscoring the value of genetic data for run reconstruction. With more accurate run reconstruction methods, spawner–recruit relationships can be identified more precisely, thus providing more accurate management targets for salmon fisheries.

Some Methods for Estimating Ocean Mortality of Pacific Salmon and Applications

1965 ◽  
Vol 22 (1) ◽  
pp. 33-51 ◽  
Author(s):  
R. A. Fredin
Keyword(s):  
Mortality Rate ◽  
Freshwater Fish ◽  
Pacific Salmon ◽  
Mortality Rates ◽  
Natural Mortality ◽  
Bristol Bay ◽  
The Third

Three methods for estimating oceanic natural mortality rates of Pacific salmon under certain survival conditions are presented. Estimates of ocean mortality rates of Bristol Bay and Karluk sockeye are given. The mortality rate during the year immediately preceding the last 2 months of ocean life of Bristol Bay sockeye that migrated to sea as 3-freshwater fish in 1956 and returned as mature 3-ocean fish in 1959 is estimated to be 28.9%. The average ocean mortality rate during the penultimate year of life of 3-ocean Bristol Bay sockeye is estimated to be 19.5% for the years 1956–57 to 1960–61. The natural mortality rate during the third year of ocean life of 3-freshwater Karluk sockeye is estimated to be 28.2%. Corresponding estimates of average monthly instantaneous mortality rates are 0.028, 0.018, and 0.031, respectively.

Abstract P261: Intensive Systolic Blood Pressure Lowering Will Prevent Over 100,000 Deaths Annually

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Holly Kramer ◽  
Adam Bress ◽  
Srinivasan Beddhu ◽  
Paul Muntner ◽  
Richard S Cooper
Keyword(s):  
Blood Pressure ◽  
Mortality Rate ◽  
Systolic Blood Pressure ◽  
Mortality Rates ◽  
Mortality Data ◽  
Blood Pressure Lowering ◽  
Cvd Risk ◽  
Pressure Lowering ◽  
Annual Mortality ◽  
The U.S

Background: The Systolic Blood Pressure Intervention Trial (SPRINT) trial randomized 9,361 adults aged ≥50 years at high cardiovascular disease (CVD) risk without diabetes or stroke to intensive systolic blood pressure (SBP) lowering (≤120 mmHg) or standard SBP lowering (≤140 mmHg). After a median follow up of 3.26 years, all-cause mortality was 27% (95% CI 40%, 10%) lower with intensive SBP lowering. We estimated the potential number of prevented deaths with intensive SBP lowering in the U.S. population meeting SPRINT criteria. Methods: SPRINT eligibility criteria were applied to the National Health and Nutrition Examination Survey 1999-2006, a representative survey of the U.S. population, linked with the mortality data through December 2011. Eligibility included (1) age ≥50 years with (2) SBP 130-180 mmHg depending on number of antihypertensive classes being taken, and (3) presence of ≥1 CVD risk conditions (history of coronary heart disease, estimated glomerular filtration rate (eGFR) 20 to 59 ml/min/1.73 m 2 , 10-year Framingham risk score ≥15%, or age ≥75 years). Adults with diabetes, stroke history, >1 g/day proteinuria, heart failure, on dialysis, or eGFR<20 ml/min/1.73m 2 were excluded. Annual mortality rates for adults meeting SPRINT criteria were calculated using Kaplan-Meier methods and the expected reduction in mortality rates with intensive SBP lowering in SPRINT was used to determine the number of potential deaths prevented. Analyses accounted for the complex survey design. Results: An estimated 18.1 million U.S. adults met SPRINT criteria with 7.4 million taking blood pressure lowering medications. The mean age was 68.6 years and 83.2% and 7.4% were non-Hispanic white and non-Hispanic black, respectively. The annual mortality rate was 2.2% (95% CI 1.9%, 2.5%) and intensive SBP lowering was projected to prevent 107,453 deaths per year (95% CI 45,374 to 139,490). Among adults with SBP ≥145 mmHg, the annual mortality rate was 2.5% (95% CI 2.1%, 3.0%) and intensive SBP lowering was projected to prevent 60,908 deaths per year (95% CI 26, 455 to 76, 792). Conclusions: We project intensive SBP lowering could prevent over 100,000 deaths per year of intensive treatment.

scholarly journals Analysis of mortality from diarrheic diseases in under-five children in Brazilian cities with more than 150,000 inhabitants

2009 ◽  
Vol 25 (5) ◽  
pp. 1093-1102 ◽  
Author(s):  
Juraci Vieira Sergio ◽  
Antônio Carlos Ponce de Leon
Keyword(s):  
Mortality Rate ◽  
Time Trends ◽  
Sharp Decrease ◽  
Mortality Rates ◽  
The North ◽  
Indicator Variables ◽  
Before And After ◽  
Geographic Regions ◽  
Annual Mortality ◽  
Children Under 5

This study analyzes mortality from infectious diarrheic diseases in children under 5 years of age in Brazilian municipalities with more than 150,000 inhabitants, excluding State capitals. The annual mortality rates by municipality from 1990 to 2000 were analyzed using a multilevel model, with years as first level units nested in municipalities as second level units. The dependent variable was the yearly mortality rate by municipality, on the log scale. Polynomial time trends and indicator variables to account for differences in geographic regions were used in the modeling. Time trends were centered on 1995, so they could be modeled differently before and after 1995. From 1990 to 1995 there was a sharp decrease in mortality rates by diarrheic diseases in most Brazilian municipalities, while from 1995 to 2000 the decrease was more heterogeneous. In 1995 the North and Northeast of Brazil had higher mortality rates than the Southeast, and the differences were statistically significant. Most importantly, the study concludes that there was an important difference in the pattern of mortality rate decreases over time, comparing the country's five geographic regions.

scholarly journals Photoreceptors Diversity of Fishes Eyes: (A Review)

2019 ◽  
Vol 1 (2) ◽  
pp. 117-124
Author(s):  
Abdul Razak
Keyword(s):  
Freshwater Fish ◽  
Reef Fish ◽  
Deep Sea ◽  
Fish Eye ◽  
Sea Fish

This article is a review about the diversity of photoreceptors in various fishes. In this article, the author discusses the photoreceptors of freshwater fish, reef fish, sharks and tuna, and deep sea fish. The purpose of this article are to provides illustration and  explanations about the diversity of photoreceptor of fish eye and its relationship with the ecosystem. The information is important in the development of fishery technology.

Paddlefish Management, Propagation, and Conservation in the 21st Century

2009 ◽  
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Mortality Rate ◽  
Population Density ◽  
21St Century ◽  
High Growth ◽  
High Growth Rate ◽  
Demographic Groups ◽  
Annual Mortality ◽  
Remnant Population

<em>Abstract</em>.—Paddlefish <em>Polyodon spathula </em>vanished from areas of the upper Tombigbee River basin in Mississippi and Alabama during the 1950s, long before channelization and damming associated with construction of the Tennessee-Tombigbee Waterway (TTW) were completed in 1984. This study was undertaken to assess distribution and population dynamics of any remaining stock. Paddlefish were not captured in upstream impoundments, but an unexploited remnant population was located in the downstream impoundment: Demopolis Lake, Alabama. Paddlefish in Demopolis Lake were characterized by a population density of 2.6 fish/ha, high growth rate relative to more northern populations, and natural annual mortality rate (<em>A </em>= 0.406) similar to other southern populations. Two wintering habitats (cutoff bendways) were heavily utilized by paddlefish. Large males primarily inhabited the more lotic bendway while females and small males were more common in the more lentic bendway, indicating differential importance of habitats among demographic groups. The restricted distribution of TTW paddlefish and demographic differences between habitats suggest that areas heavily utilized by paddlefish should be protected from further degradation. Sedimentation has resulted in reductions of bendway depth and reduced connectivity of backwaters, reducing availability of suitable paddlefish habitat. Restoring connectivity of bendways through dredging could reverse this trend and provide other benefits to fisheries.

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