Comparison of Two Methods of Estimating the Variance of the Estimate of Catch Per Unit Effort

1980 ◽  
Vol 37 (12) ◽  
pp. 2346-2351 ◽  
Author(s):  
S. J. Smith
Keyword(s):  
Variance Estimation ◽  
Catch Per Unit Effort ◽  
Jackknife Method ◽  
Unit Effort ◽  
Jackknife Estimator

Two methods of estimating the variance of the estimate of catch per unit effort are compared empirically here. The second method, an application of the Jackknife estimator proved to be the overall best technique due to its generality. In addition the Jackknife method provides means for the estimation of confidence intervals.Key words: catch per unit effort, variance estimation, Jackknife estimator

Comparison of Two Methods of Combining Catch-Per-Unit-Effort Data from Geographic Regions

1982 ◽  
Vol 39 (6) ◽  
pp. 837-846 ◽  
Author(s):  
Terrance J. Quinn II ◽  
Stephen H. Hoag ◽  
G. Morris Southward
Keyword(s):  
Variance Estimation ◽  
Fishing Effort ◽  
Data Sampling ◽  
Catch Per Unit Effort ◽  
Pacific Halibut ◽  
Unit Effort ◽  
Combining Data ◽  
Geographic Regions ◽  
Substantial Bias ◽  
Over Time

We examined two methods of combining catch-and-effort data from small geographic regions into large regulatory areas to estimate catch-per-unit-effort (CPUE): (1) weighting regional CPUE by bottom area occupied by the population; (2) weighting by fishing effort. Variance estimates and other statistical properties are presented for CPUE estimates by region and for the two methods, for the type of fishery where total catch is known. The CPUE estimator from area-weighting is approximately unbiased as an index of population density; the CPUE estimator from effort-weighting is biased but less variable than the former. Conditions of similarity are derived for estimators from the two methods to be identical, or, less restrictively, to show the same trend over time. In general, the area-weighted method is preferred, if sufficient samples are taken from all pertinent regions in the regulatory area. However, the effort-weighted method may be used with a gain in precision and no substantial bias, if there are no substantial changes in relative CPUE and effort among regions, or if relative CPUE and effort are inversely related. The two methods applied to catch and effort data for Pacific halibut (Hippoglossus stenolepis) and to produce highly similar CPUE estimates over time, despite large relative changes in both CPUE and effort among regions. The reasons for the similarity are traced back to conditions in the fishery.Key words: catch-per-unit-effort, combining data, sampling commercial fisheries, variance estimation, comparison of methods

Qarun Lake fisheries; Fishing gears, Species composition and Catch per unit effort

2014 ◽  
Vol 18 (2) ◽  
pp. 39-49
Author(s):  
Sabry El-Serafy ◽  
Alaa El-Haweet ◽  
Azza El-Ganiny ◽  
Alaa El-Far
Keyword(s):  
Species Composition ◽  
Catch Per Unit Effort ◽  
Unit Effort ◽  
Fishing Gears ◽  
Lake Fisheries

scholarly journals Modeling of Lake Malombe Annual Fish Landings and Catch per Unit Effort (CPUE)

Forecasting ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 39-55
Author(s):  
Rodgers Makwinja ◽  
Seyoum Mengistou ◽  
Emmanuel Kaunda ◽  
Tena Alemiew ◽  
Titus Bandulo Phiri ◽  
...  
Keyword(s):  
Time Series ◽  
Information Criterion ◽  
Coefficient Of Determination ◽  
Series Data ◽  
Efficiency Coefficient ◽  
Arima Models ◽  
Catch Per Unit Effort ◽  
Annual Fish ◽  
Unit Effort ◽  
The Mean

Forecasting, using time series data, has become the most relevant and effective tool for fisheries stock assessment. Autoregressive integrated moving average (ARIMA) modeling has been commonly used to predict the general trend for fish landings with increased reliability and precision. In this paper, ARIMA models were applied to predict Lake Malombe annual fish landings and catch per unit effort (CPUE). The annual fish landings and CPUE trends were first observed and both were non-stationary. The first-order differencing was applied to transform the non-stationary data into stationary. Autocorrelation functions (AC), partial autocorrelation function (PAC), Akaike information criterion (AIC), Bayesian information criterion (BIC), square root of the mean square error (RMSE), the mean absolute error (MAE), percentage standard error of prediction (SEP), average relative variance (ARV), Gaussian maximum likelihood estimation (GMLE) algorithm, efficiency coefficient (E2), coefficient of determination (R2), and persistent index (PI) were estimated, which led to the identification and construction of ARIMA models, suitable in explaining the time series and forecasting. According to the measures of forecasting accuracy, the best forecasting models for fish landings and CPUE were ARIMA (0,1,1) and ARIMA (0,1,0). These models had the lowest values AIC, BIC, RMSE, MAE, SEP, ARV. The models further displayed the highest values of GMLE, PI, R2, and E2. The “auto. arima ()” command in R version 3.6.3 further displayed ARIMA (0,1,1) and ARIMA (0,1,0) as the best. The selected models satisfactorily forecasted the fish landings of 2725.243 metric tons and CPUE of 0.097 kg/h by 2024.

Environmental drivers of golden tilefish ( Lopholatilus chamaeleonticeps ) commercial landings and catch‐per‐unit‐effort

2021 ◽  
Author(s):  
Geneviève Nesslage ◽  
Vyacheslav Lyubchich ◽  
Paul Nitschke ◽  
Erik Williams ◽  
Churchill Grimes ◽  
...  
Keyword(s):  
Environmental Drivers ◽  
Catch Per Unit Effort ◽  
Unit Effort

Ecological and environmental factors affecting the foraging activity of the White-bellied Heron Ardea insignis (Hume, 1878) in Bhutan

2021 ◽  
pp. 1-18
Author(s):  
PEMA KHANDU ◽  
GEORGE A. GALE ◽  
SARA BUMRUNGSRI
Keyword(s):  
Relative Abundance ◽  
Habitat Restoration ◽  
Prey Species ◽  
Catch Per Unit Effort ◽  
Factors Affecting ◽  
Prey Biomass ◽  
Gravel Mining ◽  
Unit Effort ◽  
Prey Preferences ◽  
The Government

Summary White-bellied Heron Ardea insignis (WBH) is critically endangered, but we lack data on many aspects of its basic ecology and threats to the species are not clearly understood. The goal of this study was to analyse WBH foraging microhabitat selection, foraging behaviour, and prey preferences in two river basins (Punatsangchhu and Mangdechhu) in Bhutan which are likely home to one of the largest remaining populations of WBH. We also explored the relationship between the relative abundance of the WBH and prey biomass catch per unit effort within four foraging river microhabitats (pool, pond, riffle and run). Prey species were sampled in 13 different 100-m thalweg lengths of the rivers using cast nets and electrofishing gear. Riffles and pools were the most commonly used microhabitats; relative abundance was the highest in riffles. The relative abundance of WBH and prey biomass catch per unit effort (CPUE) also showed a weak but significant positive correlation (rs = 0.22). The highest biomass CPUE was observed in riffles while the lowest was found in the ponds. From the 97 prey items caught by the WBH, 95% of the prey were fish. The WBH mainly exploited three genera of fish (Garra, Salmo, and Schizothorax) of which Schizothorax (64%) was the most frequently consumed. This study provides evidence in support of further protection of critical riverine habitat and fish resources for this heron. Regular monitoring of sand and gravel mining, curbing illegal fishing, habitat restoration/mitigation, and developing sustainable alternatives for local people should be urgently implemented by the government and other relevant agencies. Further study is also required for understanding the seasonal variation and abundance of its prey species in their prime habitats along the Punatsangchhu and Mangdechhu basins.

Modelling catch per unit effort of the Black Volta near the Bui dam in Ghana

2016 ◽  
Vol 55 (2) ◽  
pp. 126-133
Author(s):  
Elliot H. Alhassan ◽  
Patrick K. Ofori-Danson ◽  
Francis K. E. Nunoo
Keyword(s):  
Catch Per Unit Effort ◽  
Unit Effort

Predation by southern sea lions (Otaria flavescens) on artisanal fishing catches in Uruguay

2002 ◽  
Vol 53 (8) ◽  
pp. 1161 ◽  
Author(s):  
Diana Szteren ◽  
Enrique Páez
Keyword(s):  
Significant Relationship ◽  
Shallow Waters ◽  
Fishing Gear ◽  
Artisanal Fishery ◽  
Artisanal Fishing ◽  
Catch Per Unit Effort ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
Unit Effort

Southern sea lions (Otaria flavescens) forage in coastal fishery grounds in shallow waters, where they interact with coastal fishing activities. The main objective of this research was to evaluate the predation of southern sea lions on artisanal fishery catches and thus determine whether interactions with sea lions affected catches. Between July 1997 and March 1998, we observed 53 fishing events onboard artisanal fishing boats in four localities. The presence and number of sea lions around the boat and the numbers of each fish species consumed by sea lions were recorded by an onboard observer. To estimate the damage caused by sea lions to fishery catches, we considered two scenarios, a conservative scenario and a maximized scenario. Predation on catches was observed in 50.9% of all the fishing events and up to four sea lions were sighted in 67.9% of fishing events. Considering a conservative scenario, predation varied from 0.8 to 9.1% of the catch per unit effort (CPUE) depending on the location. Considering the maximized scenario, predation varied from 3.4 to 46.2%. However, no significant relationship was found between CPUE and the number of sea lions in any locality or with either type of fishing gear. Furthermore, CPUE did not differ in the presence or absence of sea lion interactions and predation per unit effort did not vary between localities or seasons. It was concluded that neither the presence of sea lions nor the damage they cause were responsible for variations in CPUE.

Wind-Aided Recruitment of Canadian Arctic Cisco (Coregonus autumnalis) into Alaskan Waters

1988 ◽  
Vol 45 (5) ◽  
pp. 906-910 ◽  
Author(s):  
Robert G. Fechhelm ◽  
David B. Fissel
Keyword(s):  
Time Series ◽  
Canadian Arctic ◽  
Wind Data ◽  
Commercial Fishery ◽  
Catch Per Unit Effort ◽  
Longshore Currents ◽  
Unit Effort ◽  
Colville River ◽  
Young Of The Year ◽  
Mackenzie River

Summer wind data collected at Barter Island, Alaska, were compared with commercial fishery catches of arctic cisco (Coregonus autumnalis) at the Colville River, Alaska, for the period 1967–85. There was a significant (p = 0.036) association between yearly catch-per-unit-effort and the percent of easterly winds after adjusting for a 5-yr differential in the two time series. Results suggest that young-of-the-year fish which spawn in Canada's Mackenzie River are aided in their westward dispersal into Alaskan waters via wind-driven longshore currents. The greater the prevalence of easterly winds (westerly currents), the greater the recruitment. Increased recruitment manifests itself as an increase in Alaskan commercial fishery catch some 5-yr later when fish have grown to a size that renders them susceptible to commercial nets.

scholarly journals PRODUKTIVITAS ALAT TANGKAP PANCING ULUR DI PROVINSI NUSA TENGGARA BARAT

2020 ◽  
Vol 1 (2) ◽  
pp. 53
Author(s):  
Ratih Purnama Sari ◽  
Nora Akbarsyah
Keyword(s):  
Catch Per Unit Effort ◽  
Unit Effort

Sebagian besar nelayan di Nusa Tenggara Barat (NTB) menggunakan pancing ulur (handline) sebagai alat tangkap (Santoso 2016). Jumlah alat tangkap ini mengalami peningkatan dari tahun 2008 hingga tahun 2012. Produksi perikanan pancing ulur juga menghasilkan lebih banyak hasil tangkapan dibandingkan dengan alat tangkap lain. Gejala penangkapan berlebih (over fishing) dapat diatasi dengan memanfaatkan sumberdaya perikanan yang berkelanjutan. Armada penangkapan ikan yang tersebar di beberapa lokasi perlu mengikuti ketersediaan stok ikan agar dapat diperoleh keuntungan secara ekonomi. Penelitian ini bertujuan untuk mengkaji dan membandingkan nilai produktivitas alat tangkap pancing ulur (hand line) yang digunakan di beberapa lokasi wilayah Nusa Tenggara Barat. Produktivitas yang diukur dalam penelitian ini adalah produktivitas alat tangkap pancing ulur. Hasil yang diperoleh menunjukkan bahwa peningkatan total hasil tangkapan dari tahun 2009 hingga 2010 adalah sebesar 22,62% yang diikuti dengan peningkatan total trip penangkapan sebesar 30,57%. Jumlah total trip penangkapan terus meningkat hingga tahun 2011 sedangkan total hasil tangkapan menurun menjadi sebesar 27,32% dari tahun 2010. Tren catch per unit effort (CPUE) untuk mengalami peningkatan 65,59% dari tahun 2010 ke 2011 dan mengalami penurunan sebesar 83,84% dari tahun 2011 sampai dengan tahun 2013. Nelayan meningkatkan jumlah armada penangkapan dengan harapan untuk meningkatkan jumlah hasil tangkapan, tetapi pada hasil nya dititik tertentu penambahan alat tangkap tidak sebanding dengan jumlah hasil tangkapan yang diterima.

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