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.

scholarly journals Interactions between the South American sea lion (Otaria flavescens) and the artisanal fishery off Coquimbo, northern Chile

2008 ◽  
Vol 65 (9) ◽  
pp. 1739-1746 ◽  
Author(s):  
Sabine Goetz ◽  
Matthias Wolff ◽  
Wolfgang Stotz ◽  
Mario J. Villegas
Keyword(s):  
South American ◽  
Northern Chile ◽  
Artisanal Fishery ◽  
The South ◽  
Sea Lion ◽  
Management Options ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
South American Sea Lion ◽  
Fishing Vessels

Abstract Goetz, S., Wolff, M., Stotz, W., and Villegas, M. J. 2008. Interactions between the South American sea lion (Otaria flavescens) and the artisanal fishery off Coquimbo, northern Chile. – ICES Journal of Marine Science, 65: 1739–1746. The South American sea lion (Otaria flavescens) forages in coastal waters, where it interacts with fisheries and causes considerable economic loss by removing some catch and damaging gear. This study describes for the fishery region of Coquimbo (Chile) where, when, and with what type of gear interactions occur, characterizes the animals involved (group size, sex, and age), and derives some management recommendations. The study was based on 55 interviews with fishers and observations aboard fishing vessels in the main fishing sectors between October 2003 and March 2004. Interactions were primarily at night (88% of interviewees fished at night), in the bay (“Bahía”) of Coquimbo (81% of interviewees fished in this sector), where shoaling fish were abundant, and with purse-seines (100% of interviewees used this gear). Although some large groups of sea lions were seen, most comprised 1–10 animals. Most animals that interacted with the fishing gear were males (67%), probably because of the different feeding strategies of the two sexes. Management options discussed include the adjustment of fisheries to foraging behaviour of sea lions, and the controlled elimination of conflicting animals.

First observations of operational interactions between bottom-trawling fisheries and South American sea lion, Otaria flavescens in south-central Chile

2012 ◽  
Vol 93 (2) ◽  
pp. 489-494 ◽  
Author(s):  
Pablo Reyes ◽  
Rodrigo Hucke-Gaete ◽  
Juan Pablo Torres-Florez
Keyword(s):  
South American ◽  
The South ◽  
Sea Lion ◽  
Central Chile ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
South American Sea Lion ◽  
South Central ◽  
By Catch ◽  
Working Day

This paper presents results of a study conducted on the trawling industrial fishery fleet of Merluccius gayi in south-central Chile, and the resulting interactions with the South American sea lion (Otaria flavescens). This study is based on observations made during September 2004, when incidental sea lion catch in the trawls was 6.3 sea lions/working day (1.2 sea lions/trawl−1). A total of 82 animals were incidentally caught, of which 12 were found dead, and the 70 remaining suffered from internal bleeding and/or fractures as a result of their capture. 83.3% of the fatalities occurred during nocturnal trawls, which comprise 30% of all observed trawls. Possible mechanisms of sea lion take are discussed. This note presents the first records of sea lions incidental by-catch by the trawler fleet along the south-east Pacific coast of Chile.

scholarly journals South American sea lions (Otaria flavescens) and killer whales (Orcinus orca) attending chub mackerel (Scomber japonicus) commercial trawl fisheries over the Patagonian Shelf: a first report

2015 ◽  
Vol 10 (1) ◽  
pp. 48-51
Author(s):  
Juan Pablo Seco Pon ◽  
Marco Favero
Keyword(s):  
Antipredator Behaviour ◽  
Commercial Fishing ◽  
South American ◽  
Killer Whales ◽  
Sea Lion ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
Trawl Fishery ◽  
Fishing Vessels ◽  
Almost All

Killer whale-seal interactions have been reported for almost all pinniped species globally. However the literature on offshore interactions between killer whales and sea lions is rare for the South Atlantic, particularly in Argentine waters. Here we report for the first time the harassment of a South American sea lion (Otaria flavescens) by killer whales (Ornicus orca) while attending commercial fishing vessels in offshore national waters and describe a novel sea lion antipredator behaviour. These observations were made during an ongoing survey to assess seabird-fisheries interactions in the commercial trawl fishery off Argentina.

scholarly journals Behaviour of the southern sea lion (Otaria flavescens) and consumption of the catch during purse-seining for jack mackerel (Trachurus symmetricus) off central Chile

2003 ◽  
Vol 60 (5) ◽  
pp. 1003-1011 ◽  
Author(s):  
L.A Hückstädt ◽  
T Antezana
Keyword(s):  
Purse Seine ◽  
Fishing Ground ◽  
Jack Mackerel ◽  
Sea Lion ◽  
Central Chile ◽  
Otaria Flavescens ◽  
Sea Lions ◽  
The Impact ◽  
Species Being ◽  
Purse Seining

Abstract The fishery for jack mackerel (Trachurus symmetricus) off central Chile competes for the resource with southern sea lions (Otaria flavescens), and during purse-seining makes the fish more accessible to the pinnipeds. Interactions with sea lions were recorded during 31 purse-seine sets off central Chile during October 1999. The sea lion behaviour associated with the fishing operations was distinctive. Feeding, movement, predator avoidance, and resting displays were identified. The sea lions approached the purse-seiner as soon as net-setting began. The number of sea lions per set (0–50) was seemingly unaffected by school size of jack mackerel, number of purse-seiners on the fishing ground, whether fishing was by night or by day, the presence of killer whales, or the species being targeted. However, the number of sea lions at a purse-seine differed significantly between fishing grounds. Other effects of fishing operations on O. flavescens included incidental mortality and capture. The amount of fish consumed by the sea lions at a set was as much as 0.4% of the catch. The results of the interaction are documented and discussed in the light of likely interaction with the whole sea lion population, as well as the impact of the interaction on the fishery.

scholarly journals DINAMIKA PERIKANAN KERAPU DI TAMAN NASIONAL KARIMUNJAWA (Grouper Fishery Dynamics in Karimunjawa National Park)

2016 ◽  
Vol 4 (2) ◽  
pp. 175
Author(s):  
Irfan Yulianto ◽  
Budy Wiryawan ◽  
Am Azbas Taurusman ◽  
Prihatin I. Wahyuningrum ◽  
Vita R. Kurniawati
Keyword(s):  
National Parks ◽  
National Park ◽  
Statistical Tests ◽  
Monsoon Season ◽  
Fishing Gear ◽  
Catch Per Unit Effort ◽  
The West ◽  
Unit Effort ◽  
Target Fish ◽  
Java Sea

<p>ABSTRACT<br />Karimunjawa National Park is one of the national parks that have the objective to maintain fish populations in the Java Sea, where one of them is grouper. Grouper is one of the target fish in the national park. The objective of this study is to assess the conditions and dynamics of the grouper fishery in Karimunjawa National Park. Fish landing surveys were conducted to collect the data. Fishing gear types, grouper species, and weight of each species were collected. Calculation of Catch per Unit Effort (CPUE) per month and two-way ANOVA statistical tests were used for data analysis. Results of this study indicated that catches of grouper using speargun was significantly higher than the catch using handline. There was a seasonal cycle of the grouper catch, where the value of the highest CPUE occurred in transitional season between the west and east monsoon season, from March to May.<br />Key words: CPUE, grouper fishery, Karimunjawa National Park</p><p>-------</p><p><br />ABSTRAK<br />Taman Nasional Karimunjawa merupakan salah satu taman nasional yang salah satu tujuannya untuk mempertahankan populasi ikan di Laut Jawa, dimana salah satunya adalah perikanan kerapu. Ikan kerapu merupakan salah satu target penangkapan di perairan Taman Nasional Karimunjawa. Tujuan penelitian ini adalah mengetahui kondisi dan dinamika perikanan kerapu di Taman Nasional Karimunjawa. Survei pendaratan ikan dilakukan untuk pengumpulan data. Data yang dikumpulkan dalam penelitian ini adalah alat tangkap yang digunakan untuk menangkap ikan kerapu, jenis hasil tangkapan, dan berat masing-masing jenis hasil tangkapan setiap trip. Perhitungan nilai Catch per Unit Effort (CPUE) setiap bulan dan uji statistik two ways ANOVA digunakan untuk analisis data. Hasil penelitian ini menunjukkan bahwa hasil tangkapan ikan kerapu dengan menggunakan speargun lebih tinggi dan berbeda nyata secara statistik dibandingkan hasil tangkapan dengan menggunakan pancing. Terdapat siklus musiman hasil tangkapan, dimana nilai CPUE tertinggi terjadi pada musim peralihan antara musim barat dan musim timur yakni dari bulan Maret hingga Mei.<br />Kata kunci: CPUE, perikanan kerapu, Taman Nasional Karimunjawa</p>

scholarly journals Seasonal catch composition and catch per unit effort of coastal fishery in Yenişakran (Çandarlı Bay, Aegean Sea)

2020 ◽  
Vol 37 (1) ◽  
pp. 9-14
Author(s):  
Tuğçe Şensurat Genç ◽  
Okan Akyol
Keyword(s):  
Aegean Sea ◽  
Fishing Gear ◽  
Catch Per Unit Effort ◽  
Sandy Bottom ◽  
Fishing Trip ◽  
Unit Effort ◽  
Catch Composition

This study presents the catch records of a coastal fisherman during daily fishing trip between 2017 and 2018 in Yenişakran, Çandarlı Bay (Aegean Sea). The trammel net and longline were used at depths of 5-25 m on a sandy bottom and the sea meadows during the year. A total of 39 species were identified from the both trammel netting and the longlining. Mean catch per unit effort (CPUE) values (8.7±0.1 kg/1000 m net and 12.9±0.8 kg/1000 hooks) shown that longlining was more efficient fishing gear than the trammel netting. In terms of mean CPUE values, there is significantly difference between trammel netting and longlining (p<0.05).

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.

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