Historical abundance of Puget Sound steelhead, Oncorhynchus mykiss, estimated from catch record data

2011 ◽  
Vol 68 (3) ◽  
pp. 498-510 ◽  
Author(s):  
N. Gayeski ◽  
B. McMillan ◽  
P. Trotter
Keyword(s):  
Oncorhynchus Mykiss ◽  
Puget Sound ◽  
Total Abundance ◽  
Commercial Catch ◽  
Freshwater Habitat ◽  
Abundance Estimates ◽  
Rivers And Streams ◽  
Average Abundance ◽  
Record Data ◽  
Unreported Catches

We used reported commercial catch data and historical information regarding unreported catches to estimate the abundance of winter steelhead, Oncorhynchus mykiss , in Puget Sound rivers in 1895, the year in which the peak commercial catch of steelhead occurred. We employed a Bayesian analysis to address the uncertainties associated with the estimation process and report abundance estimates for four large northern Puget Sound rivers and for the remaining aggregate of rivers and streams in Puget Sound. The central 90% of the posterior distribution of total abundance ranged from 485 000 to 930 000, with a mode of 622 000. Compared with the 25-year average abundance for all of Puget Sound of 22 000 for the 1980–2004 period, our results show that current abundance is likely only 1%–4% of what it was prior to the turn of the 20th century. Loss of freshwater habitat alone can account for this reduction in abundance only if there was an extraordinary decline in productivity. Our estimates of historical abundance should better inform the development of recovery goals for Puget Sound steelhead.

Biology and Management of Dogfish Sharks

2009 ◽  
Keyword(s):  
Life History ◽  
Pacific Coast ◽  
Puget Sound ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
Dietary Analysis ◽  
Strait Of Georgia ◽  
Food Items ◽  
Abundance Estimates ◽  
Commercial Species

Abstract.—Spiny dogfish <em>Squalus acanthias </em>have been an important commercial species on Canada’s Pacific coast for more than 130 years. In this study we show that the spiny dogfish life history results in juveniles remaining in pelagic waters for 10–15 years after birth, with lengths up to about 60 cm. Abundance estimates show that the numbers of these young dogfish, as well as some older dogfish in the pelagic waters, appear to represent a relatively large percentage of the population in these two regions. Dietary analysis shows that while euphausiids and teleosts constitute the major food items, regardless of size/age, dogfish feed on a number of species within the ecosystem. After about 15 years, there is a movement into demersal habitats where individuals eventually mature. Because dogfish are long lived, and because they are found throughout the pelagic zone and demersal habitats, it is probable that they play a key role in the Strait of Georgia and Puget Sound ecosystems.

scholarly journals ANALISIS KELIMPAHAN TOTAL BAKTERI COLIFORM DI PERAIRAN MUARA SUNGAI SAYUNG, MOROSARI, DEMAK (Analysis of Total Abundance of Coliform Bacteria at the Sayung River Estuary, Morosari, Demak)

2018 ◽  
Vol 14 (1) ◽  
pp. 30
Author(s):  
Lani Febriana Safitri ◽  
Niniek Widyorini ◽  
Oktavianto Eko Jati
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Oxygen ◽  
Random Sampling ◽  
River Estuary ◽  
Total Coliform ◽  
Coliform Bacteria ◽  
Total Abundance ◽  
Average Abundance ◽  
Total Coliform Bacteria

Perairan Muara Sungai Sayung terletak di wilayah Kabupaten Demak sebelah barat. Perairan ini telah dipengaruhi oleh berbagai aktivitas manusia yang menyebabkan terjadinya penurunan kualitas perairan. Bakteri Coliform merupakan bakteri gram negatif yang berbentuk batang dan tidak membentuk spora. Bakteri ini merupakan bakteri indikator terjadinya pencemaran perairan maupun indikator keberadaan bakteri patogen lainnya. Perhitungan total bakteri Coliform perlu dilakukan untuk mengetahui adanya pencemaran limbah organik yang terjadi di Perairan Muara Sungai Sayung, Morosari, Demak. Tujuan dari penelitian ini adalah untuk mengetahui kelimpahan total bakteri Coliform, dan status perairan di Perairan Muara Sungai Sayung, Morosari, Demak. Penelitian ini juga bertujuan untuk mengetahui hubungan dari jumlah total bakteri Coliform dengan bahan organik terlarut dan oksigen terlarut (DO). Pelaksanaan penelitian ini dilakukan pada bulan Mei 2018. Metode yang digunakan dalam penelitian ini adalah metode survei dan teknik pengambilan sampel menggunakan metode random sampling yang dilakukan pada lima stasiun. Hasil penelitian menunjukkan bahwa kelimpahan rata-rata total bakteri Coliform yang diperoleh berkisar antara 4 x 103 – 550 x 10 3/100ml. Kelimpahan rata-rata total bakteri Coliform yang diperoleh pada setiap stasiun menunjukkan bahwa kandungan total bakteri Coliform telah melebihi baku mutu air menurut Keputusan Menteri Lingkungan Hidup Nomor 51 Tahun 2004. Keberadaan total bakteri Coliform memiliki hubungan yang lemah dengan kandungan bahan organik terlarut, sedangkan keberadaan total bakteri Coliform memiliki hubungan yang cukup dengan oksigen terlarut (DO) di perairan Muara Sungai Sayung Morosari, Demak. Sayung River Estuary is located in the western part of Demak Regency. This estuary has been affected by various human activities which have led to a decline in water quality. Coliform bacteria are a gram-negative bacteria that are rod-shaped and do not form spores. This bacterium is an indicator bacteria of water pollution and an indicator of the presence of other pathogenic bacteria. Total Coliform bacteria calculation needs to be carrid out to find out if there any contamination of organic waste in Sayung River Estuary, Morosari, Demak.. The purpose of this research was to determine total abundance of Coliform bacteria, water quality in Sayung River Estuary, Morosari, Demak and relationship between the total abundance of Coliform bacteria with dissolved organic matter and dissolved oxygen (DO). This research was carried out in May 2018. The method that used in this research were survey method and the sampling technique was random sampling method in five stations. The results showed that the average abundance of total Coliform bacteria obtained ranged between 4 x 103 - 550 x 103 / 100ml. Average abundance of total Coliform bacteria obtained at each station shows that the total content of Coliform bacteria has exceeded the water quality standard according to Minister of Environment Decree number 51 of 2004. The total presence of Coliform bacteria has a weak relationship with the content of dissolved organic matter, while the total number of Coliform bacteria have sufficient relationship with dissolved oxygen (DO) in the Sayung River Estuary,Morosari, Demak.

Effects of flow fluctuations on habitat use and survival of age-0 rainbow trout (Oncorhynchus mykiss) in a large, regulated river1This article is a companion to Korman et al. 2011, published this issue.

2011 ◽  
Vol 68 (6) ◽  
pp. 1097-1109 ◽  
Author(s):  
Josh Korman ◽  
Carl Walters ◽  
S.J.D. Martell ◽  
W.E. Pine ◽  
Andrew Dutterer
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Early Life History ◽  
Regulated Rivers ◽  
Minimum Flow ◽  
Glen Canyon Dam ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Flow Fluctuations ◽  
Abundance Estimates ◽  
Hourly Variation

We evaluated effects of reduced hourly variation in flow from Glen Canyon Dam on survival of age-0 rainbow trout ( Oncorhynchus mykiss ) in the Colorado River, Arizona, USA, based on monthly abundance estimates. The proportion of the age-0 population in low-angle shorelines, which are potentially more sensitive to flow variability, declined from 70% in June to 20% in November as fish grew and made an ontogenetic habitat shift to deeper habitat. Average daily instantaneous mortality between August and September was 0.008 units lower in years when there was no change in the minimum flow compared with years when there was a sudden 50% reduction in the minimum flow. However, mortality was 0.006 units higher during the fall when there was no hourly variation in flow compared with years when flows fluctuated. As a result of these opposing patterns, 3-month age-0 survival across steady (0.31) and unsteady (0.28) flow regimes were very similar. While additional replication is required to strengthen inferences about effects of steadier flows, we demonstrate the utility of early life history monitoring for evaluating effects of flow management on fish populations in regulated rivers.

Spatial Analysis of Bering Sea Groundfish Survey Data Using Generalized Additive Models

1992 ◽  
Vol 49 (7) ◽  
pp. 1366-1378 ◽  
Author(s):  
Gordon Swartzman ◽  
Chisheng Huang ◽  
Stephen Kaluzny
Keyword(s):  
Survey Data ◽  
Bering Sea ◽  
Generalized Additive Models ◽  
Sampling Procedure ◽  
Additive Models ◽  
Trawl Survey ◽  
Flatfish Species ◽  
Eastern Bering Sea ◽  
Abundance Estimates ◽  
Average Abundance

Generalized additive models (GAM) are herein applied to trawl survey data in the eastern Bering Sea with an eye to (1) detecting trends in groundfish distributions and (2) improving abundance estimates by including the trend. GAM is a statistical method, analogous to regression, but without the assumptions of normality or linearity that relate a response variable (in this case, fish abundance) to location (latitude and longitude) and associated environmental variables (e.g. depth and bottom temperature). GAM provided reasonable (i.e. high r2) fits to the spatial distribution of five flatfish species and was able to define a spatial "signature" for each species, namely their preferred depth and temperature range. GAM also gave lower average abundance and abundance variability estimates for these five flatfish species than the stratified sampling procedure previously employed.

Predicting fish abundance using single-pass removal sampling

2000 ◽  
Vol 57 (5) ◽  
pp. 951-961 ◽  
Author(s):  
Matthew G Mitro ◽  
Alexander V Zale
Keyword(s):  
Rainbow Trout ◽  
Prediction Interval ◽  
Prediction Intervals ◽  
Total Abundance ◽  
Simulated Population ◽  
River Section ◽  
Single Pass ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Abundance Estimates ◽  
Removal Sampling

Three-pass removal data for juvenile rainbow trout (Oncorhynchus mykiss) along bank areas of the Henrys Fork of the Snake River, Idaho, were used to construct a mean capture probability (MCP) model to predict abundance from single-pass catch data. We evaluated the MCP model by simulation. The precision of the MCP model was poor when predicting abundance within a specific bank unit. MCP model prediction intervals were about 7.5 times greater than three-pass removal intervals. However, the MCP model performed about the same as three-pass removal for predicting total abundance in a river section from multiple bank samples. We evaluated how the MCP model can be used to improve precision of total abundance estimates. Reallocating effort to sample 150 bank units by single-pass removal rather than 50 bank units by three-pass removal resulted in a 48% increase in prediction interval precision for a simulated population of 10 000 fish. Precision also increased when allocating effort to sampling more bank units of smaller length versus fewer bank units of longer length. Sampling 1500 m of bank as one hundred 15-m bank units increased precision by about 28% versus sampling fifty 30-m bank units and by about 50% versus sampling twenty-five 60-m bank units.

scholarly journals Evaluating the uncertainty of abundance estimates from acoustic surveys using geostatistical simulations

2009 ◽  
Vol 66 (6) ◽  
pp. 1377-1383 ◽  
Author(s):  
Mathieu Woillez ◽  
Jacques Rivoirard ◽  
Paul G. Fernandes
Keyword(s):  
Acoustic Backscatter ◽  
Fish Length ◽  
Total Abundance ◽  
Geostatistical Model ◽  
Abundance Estimates ◽  
Structural Relationships ◽  
Coefficients Of Variation ◽  
Data Points ◽  
Acoustic Surveys ◽  
Survey Estimates

Abstract Woillez, M., Rivoirard, J., and Fernandes, P. G. 2009. Evaluating the uncertainty of abundance estimates from acoustic surveys using geostatistical simulations. – ICES Journal of Marine Science, 66: 1377–1383. Geostatistical simulations, which can reproduce the spatial variability of a variable, are particularly helpful in estimating the uncertainty associated with the combination of different sources of variability. Acoustic surveys offer an example of such complex situations, where different data (e.g. acoustic backscatter, fish length, and fish age) must be combined to estimate abundance and its associated uncertainty. In this paper, the uncertainty of Scottish herring acoustic-survey estimates is investigated using these techniques. A specific multivariate, geostatistical model is used to describe the structural relationships, which includes highly skewed distributions of the acoustic-backscatter data and incorporates relationships between depth, mean length, and proportions-at-age. Conditional simulations, i.e. geostatistical simulations that honour the data values known at the data points, are used to generate multiple realizations of acoustic backscatter, mean length, and proportions-at-age. These are combined to produce multiple realizations of herring density over the sampled domain. Multiple realizations of total abundance and abundance-at-age are then provided. The uncertainty is assessed using basic statistics to track the significant variations of these values over the period 1989–2005. Higher coefficients of variation (CVs) are found on average for extreme ages (ages 1, 2i, 8, and 9+); otherwise, CVs are mostly around 12% for abundance-at-age and around 10% for total abundance.

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