Fishers' description of changes in fishing gear and fishing practices in the Australian South East Trawl Fishery

2001 ◽  
Vol 52 (4) ◽  
pp. 411 ◽  
Author(s):  
Pascale Baelde
Keyword(s):  
Stock Assessment ◽  
Single Species ◽  
Fishing Gear ◽  
Qualitative Synthesis ◽  
Quota System ◽  
Fish Stocks ◽  
Trawl Fishery ◽  
Individual Transferable Quota ◽  
Catch Composition ◽  
Fishing Practices

Between the mid 1980s and early 1990s, the concurrence of three major events significantly altered the structure and dynamics of the demersal trawl sector in the Australian South-East Fishery (SEF). These events included marked technological improvement, severe decline of major fish stocks and introduction of an Individual Transferable Quota system. They have led to a switch from maximizing catch volume to maximizing catch composition and quotas, with important associated changes in fishing practices and catches. To better understand these changes and their effect on stock assessment and management, an industry survey asked SEF trawl fishers to describe their fishing gear and fishing practices in detail. This paper is a qualitative synthesis of current trends in fishing that most significantly affect the single-species, logbook-dependent assessment and management of the fishery. It demonstrates how effective collaboration between scientists and fishers can benefit fisheries research and management, by helping scientists make more informed analysis and interpretations of fisheries data.

scholarly journals Application of Métier-Based Approaches for Spatial Planning and Management: A Case Study on a Mixed Trawl Fishery in Taiwan

2021 ◽  
Vol 9 (5) ◽  
pp. 480
Author(s):  
Yi-Jou Lee ◽  
Nan-Jay Su ◽  
Hung-Tai Lee ◽  
William Wei-Yuan Hsu ◽  
Cheng-Hsin Liao
Keyword(s):  
Spatial Planning ◽  
Clustering Algorithm ◽  
Fishing Gear ◽  
Target Species ◽  
Trawl Fishery ◽  
Fishery Resources ◽  
Planning And Management ◽  
Catch Composition ◽  
Fleet Dynamics

Mixed fisheries refer to fishing activities that catch more than one species simultaneously, and a species may be fished using different gear. A trawl fishery shares these features to exploit multiple species simultaneously, with diverse fishing gear and strategies. The situation becomes more complex when interactions among fleet dynamics, fishing activities, and fishery resources are involved and influence each other. Information regarding the operational patterns may be hidden in a set of long-term big data. This study aims to investigate the fishery structure and fleet dynamics of trawl fisheries in Taiwan for spatial planning and management, based on a long-term dataset from a management system that collects information by using voyage data recorders (VDR) and dockside observers. We applied a two-step data mining process with a clustering algorithm to classify the main groups of fishery resources and then identified 18 catch métiers based on catch composition. The target species, operation pattern, and fishing season were determined for each métier, and associated with the relevant fishery resources and the fishing gear used. Additionally, fishing effects on target species were estimated using information on fishing grounds and trajectories from VDR. The métier-based approach was successfully applied to define the six major fishery resources targeted by trawlers. We examined the key features of fishing activity associated with catch composition and spatial-temporal fishing metrics, which could be used to provide suggestions for the spatial planning and management of the mixed trawl fishery in the offshore waters of Taiwan.

Comment on “Differences in predicted catch composition between two widely used catch equation formulations”Appears in Can. J. Fish. Aquat. Sci. 66: 126–132.

2010 ◽  
Vol 67 (4) ◽  
pp. 763-765 ◽  
Author(s):  
R. I.C. Chris Francis
Keyword(s):  
Stock Assessment ◽  
Fishing Gear ◽  
Fishing Mortality ◽  
Instantaneous Rate ◽  
Exploitation Rate ◽  
Catch Composition ◽  
Continuous Formulation

Branch (2009. Can. J. Fish. Aquat. Sci. 66: 126–132) described the two most common catch equation formulations in stock assessment models: the continuous (Baranov) one, which represents fishing mortality as an instantaneous rate, F, and the discrete one, in which it is represented as an exploitation rate, u. He claimed that the continuous formulation is preferable at high fishing mortality where a fish could encounter multiple sets of gear within a year. This claim is wrong for two reasons. First, it is based on the false supposition that the discrete catch equations require the assumption that fish encounter at most only one set of fishing gear in a year. Second, it is not possible to determine, for a specific stock assessment, whether one formulation is preferable to another solely on the basis of information about the fishery. The appropriate way to make this decision is to see which fits the data better.

Bycatch of chondrichthyans in a coastal trawl fishery on Chubut province coast and adjacent waters, Argentina

2016 ◽  
Vol 98 (3) ◽  
pp. 605-616 ◽  
Author(s):  
J. Ruibal Núñez ◽  
N. D. Bovcon ◽  
P. D. Cochia ◽  
M. E. Góngora
Keyword(s):  
Single Species ◽  
Ecosystem Approach ◽  
Squalus Acanthias ◽  
Fishing Gear ◽  
Target Species ◽  
Trawl Fishery ◽  
Merluccius Hubbsi ◽  
By Products ◽  
Discopyge Tschudii ◽  
Mustelus Schmitti

Chondrichthyans are usually caught incidentally in fisheries for species of high commercial value and then discarded on board or landed as by-products. On the coast of Chubut province and adjacent waters (43°00′S–44°56′S) a bottom trawl fishery has developed targeted at the Patagonian shrimp (Pleoticus muelleri) and common hake (Merluccius hubbsi). Since 2005, this fishery has been monitored by the On-board Observers Program of Chubut province (POBCh). With the aim of advancing towards an ecosystem approach, POBCh not only collects information about target species but also about all the species caught by the trawl nets of the province fisheries. From the information collected by this programme it was possible to identify and record the chondrichthyan species vulnerable to the fishing gear used by the coastal fleet that operates from Puerto Rawson. The composition of the fleet catch was characterized according to the target species during the 2005–2014 period. In the analysis of 3786 hauls, 23 species of chondrichthyans (seven species of sharks, 15 species of batoids and a single species of Holocephali) were identified. Seven species showed a frequency of occurrence greater than 10% (Callorhinchus callorynchus, Discopyge tschudii, Mustelus schmitti, Sympterygia bonapartii, Psammobatis normani, Squalus acanthias and Zearaja chilensis). Species spatial distribution was evaluated and five areas of species assemblages were established. Besides the aspects related to bycatch, these analyses have contributed to the knowledge of the chondrichthyan biodiversity in the provincial coast where the fleet operates, a region with incomplete and mostly dispersed and outdated information.

scholarly journals IMPLIKASI IUU FISHING DALAM PENGELOLAAN SUMBER DAYA IKAN DI INDONESIA

2017 ◽  
Vol 1 (1) ◽  
pp. 61
Author(s):  
Subhat Nurhakim
Keyword(s):  
Fisheries Management ◽  
World Wide ◽  
Stock Assessment ◽  
National Plan ◽  
Fish Stocks ◽  
Fisheries Resources ◽  
Iuu Fishing ◽  
Global Concern ◽  
The Impact ◽  
Fishing Practices

Pada tatanan dunia, regional, dan nasional, dewasa ini isu kegiatan yang berkaitan dengan IUU fishing adalah merupakan ancaman utama terhadap sediaan ikan. Telah banyak inisiatif international yang didukung oleh organisasi internasional seperti FAO telah menyiapkan International Plan of Action dari IUU Fishing. Walaupun jumlah negara yang mencoba mengembangkan National Plan of Action dari IUU Fishing terus bertambah, tetapi dalam beberapa hal, kegiatan IUU Fishing merupakan hal yang banyak terjadi dan merupakan ancaman nyata terhadap perikanan lokal. Adalah benar bahwa perhatian dunia terhadap IUU Fishing terus meningkat sebagai akibat yang nyata penurunan sediaan ikan dunia secara drastis. Perkiraan kasar secara keseluruhan menunjukkan bahwa paling tidak 30% dari hasil tangkapan perikanan dunia diperoleh dari kegiatan IUU Fishing. Ini memperlihatkan bahwa masalah IUU Fishing tersebut meningkat dengan kuat, terutama bila dilihat dari percepatan penurunan ketersediaan sumber daya perikanan. Tulisan ini menyajikan hal-hal yang berkaitan dengan pengkajian sediaan dan pengelolaan perikanan seperti juga halnya kegiatan IUU Fishing yang terjadi di Indonesia. Dampak IUU Fishing terhadap hasil pengkajiaan sediaan pada akhirnya digunakan sebagai informasi dasar untuk pengelolaan perikanan juga dibahas. Rekomandasi disampaikan dalam kaitannya untuk mengurangi kegiatan IUU Fishing dan meningkatkan pengkajian sediaan ikan dan pengelolaan perikanan.At global, regional, and national levels, issues associated with IUU fishing activities currently constitute a major world-wide threat to fisheries stocks. There have already been many international initiatives supported by international organizations such as the FAO which have been engaged in the International Plan of Action on IUU fishing. Although an increasing number of countries are trying to develop national plan of actions on IUU fishing, in many parts, IUU fishing practices are still common place and constitute a real threat to local fishers. Indeed, there is increasing global concern about IUU fishing practices due to the fact that global fish stocks are declining drastically. Approximate estimations suggest that overall at least 30% of world-wide fisheries catch is obtained from IUU fishing activities. This shows that the problem is increasingly severe, especially in view of the accelerating overall decline in available fisheries resources. This paper presents briefly regarding stock assessment and fisheries management as well as IUU fishing activities that undertake in Indonesian waters. The impact of IUU fishing to the result of stock assessment, that finally used as basic information for fisheries management is also discuss. Recommendation ismade in relation to eliminate IUU fishing activities and improvement of stock assessment and fisheries management.

scholarly journals ASAR: A Distinct Fishing Gear Used In the Cordillera Rivers

2018 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Stock Assessment ◽  
The Other ◽  
Fishing Gear ◽  
Plant Materials ◽  
Aquatic Resources ◽  
Linguistic Differences ◽  
Rice Grains ◽  
Assessment Program ◽  
The North ◽  
Catch Composition

The Cordillera Administrative Region, dubbed as the “Watershed Cradle of the North” caters to 13 major rivers [1]. Five of which is being assessed by the National Stock Assessment Program of the Bureau of Fisheries and Aquatic Resources [2,3]. This study, under the BFAR-CAR NSAP was conducted to study the origin of the asar, a distinct fish trap being used in the Cordillera Rivers. It also wanted to determine the catch composition in six municipal landing centers identified. Data on the history and origin of the asar were obtained through interviews with fisherfolk in Abra, Kalinga, Benguet, Apayao and Ilocos Sur using open-ended questions. Data on fish composition and volume of catch were collected by NSAP-CAR data enumerators in six landing centers along the Rivers of Amburayan, Abra and Apayao-Abulug. The asar is also known as asal or kileb, a little difference due to the linguistic differences in the region. It is a passive and size selective but not species-selective fishing gear. It takes advantage of the increased volume of fish trapped during the rainy season. In Abra, asar was constructed based on basbasan – a tool used to separate rice grains from its stalk. In Benguet on the other hand was based in an old practice of filtering decaying plant materials in rice fields called asal. In Apayao, asar was introduced by Mr. Manuel Basilio, an Abrenian who migrated to Flora in 1964. NSAP data shows that 26 species of aquatic animals were caught by asar in the Cordillera Rivers in 2015. Asar as a gear contributed 5.5% to the total inland capture fisheries catch in 2015.

scholarly journals Towards sustainable demersal fisheries: NepCon image acquisition system for automatic Nephrops norvegicus detection

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252824
Author(s):  
Maria Sokolova ◽  
Fletcher Thompson ◽  
Patrizio Mariani ◽  
Ludvig Ahm Krag
Keyword(s):  
Learning Algorithm ◽  
Image Acquisition ◽  
Automatic Detection ◽  
Observation System ◽  
Fishing Gear ◽  
Learning Approaches ◽  
Nephrops Norvegicus ◽  
Trawl Fishery ◽  
Perception System ◽  
Catch Composition

Underwater video monitoring systems are being widely used in fisheries to investigate fish behavior in relation to fishing gear and fishing gear performance during fishing. Such systems can be useful to evaluate the catch composition as well. In demersal trawl fisheries, however, their applicability can be challenged by low light conditions, mobilized sediment and scattering in murky waters. In this study, we introduce a novel observation system (called NepCon) which aims at reducing current limitations by combining an optimized image acquisition setup and tailored image analyses software. The NepCon system includes a high-contrast background to enhance the visibility of the target objects, a compact camera and an artificial light source. The image analysis software includes a machine learning algorithm which is evaluated here to test automatic detection and count of Norway lobster (Nephrops norvegicus). NepCon is specifically designed for applications in demersal trawls and this first phase aims at increasing the accuracy of N. norvegicus detection at the data acquisition level. To find the best contrasting background for the purpose we compared the output of four image segmentation methods applied to static images of N. norvegicus fixed in front of four test background colors. The background color with the best performance was then used to evaluate computer vision and deep learning approaches for automatic detection, tracking and counting of N. norvegicus in the videos. In this initial phase we tested the system in an experimental setting to understand the feasibility of the system for future implementation in real demersal fishing conditions. The N. norvegicus directed trawl fishery typically has no assistance from underwater observation technology and therefore are largely conducted blindly. The demonstrated perception system achieves 76% accuracy (F-score) in automatic detection and count of N. norvegicus, which provides a significant elevation of the current benchmark.

scholarly journals Quirky patterns in time-series of estimates of recruitment could be artefacts

2014 ◽  
Vol 72 (1) ◽  
pp. 111-116 ◽  
Author(s):  
M. Dickey-Collas ◽  
N. T. Hintzen ◽  
R. D. M. Nash ◽  
P-J. Schön ◽  
M. R. Payne
Keyword(s):  
Time Series ◽  
Stock Assessment ◽  
Meta Analysis ◽  
Reference Points ◽  
Fish Stocks ◽  
Stock Recruitment ◽  
Modelling Assumptions ◽  
Meta Analyses ◽  
Recruitment Model ◽  
Recruitment Time

Abstract The accessibility of databases of global or regional stock assessment outputs is leading to an increase in meta-analysis of the dynamics of fish stocks. In most of these analyses, each of the time-series is generally assumed to be directly comparable. However, the approach to stock assessment employed, and the associated modelling assumptions, can have an important influence on the characteristics of each time-series. We explore this idea by investigating recruitment time-series with three different recruitment parameterizations: a stock–recruitment model, a random-walk time-series model, and non-parametric “free” estimation of recruitment. We show that the recruitment time-series is sensitive to model assumptions and this can impact reference points in management, the perception of variability in recruitment and thus undermine meta-analyses. The assumption of the direct comparability of recruitment time-series in databases is therefore not consistent across or within species and stocks. Caution is therefore required as perhaps the characteristics of the time-series of stock dynamics may be determined by the model used to generate them, rather than underlying ecological phenomena. This is especially true when information about cohort abundance is noisy or lacking.

scholarly journals Experimental evaluation of influence of FADs on community structure and fisheries in coastal Kenya

2018 ◽  
Vol 31 ◽  
pp. 6 ◽  
Author(s):  
Emmanuel K. Mbaru ◽  
Dorcas Sigana ◽  
Renison K. Ruwa ◽  
Elizabeth M. Mueni ◽  
Collins K. Ndoro ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Small Scale ◽  
Catch Per Unit Effort ◽  
Fish Stocks ◽  
Coastal Fisheries ◽  
Small Scale Fisheries ◽  
Open Sea ◽  
Catch Composition ◽  
Structural Indices ◽  
Fish Aggregating Devices

Fish aggregating devices (FADs) have been widely used by commercial fisheries to increase the catchability of pelagic stocks in the open sea. FADs have the potential to enhance nearshore small-scale fisheries where stocks are often overfished. This study examined changes in catch composition, abundance, catch and effort, and aspects of diversity in Kenya's nearshore coastal fisheries after deployment of anchored fish aggregating devices (AFADs). The study combined both fishery independent and dependent methods in assessing changes in fish assemblages post-deployment. Results showed orders of magnitude increase in length, weight, commercial value, and catch per unit effort (CPUE) of landed catch after deployment of FADs suggesting that FADs had a positive effect on the local fishery. Species richness at FAD sites increased post-deployment (n = 281) compared to pre-deployment values (n = 223). Simultaneous use of several complementary structural indices may be required in order to accurately describe and monitor fish assemblages around the FADs. The findings suggest that AFADs are capable of creating both short and long-term impacts on livelihoods, with the potential to deflect pressure on the overfished nearshore fish stocks. However, more research will be needed on redistribution of fish around FADs, design and placement configuration, and site selection amongst others.

scholarly journals Dictionary-Based Method for Fishing Gear Pattern Detection

10.29007/npz9 ◽  
2019 ◽  
Author(s):  
Ramón Aranda ◽  
Hugo Carlos
Keyword(s):  
Coastal Communities ◽  
Pattern Detection ◽  
Upper Paleolithic ◽  
Fishing Gear ◽  
Fish Stocks ◽  
Iuu Fishing ◽  
Marine Habitats ◽  
Automatic Information ◽  
Fishing Fleets ◽  
Unregulated Fishing

Fishing is an ancient practice that dates back to at least the beginning of the Upper Paleolithic period about 40,000 years ago. Nowadays, Fishing is one of the most important activities, as it provides a source of food and economic income worldwide. A key challenge in ecology and conservation is to decrease the Illegal, Unreported and Unregulated fishing (IUU). IUU fishing depletes fish stocks, destroys marine habitats, distorts competition, puts honest fishers at an unfair disadvantage, and weakens coastal communities, particularly in developing countries. One strategy to decrease the IUU fishing is monitoring and detecting the fishing vessel behaviors. Satellite–based Automatic Information Systems (S– AIS) are now commonly installed on most ocean–going vessels and have been proposed as a novel tool to explore the movements of fishing fleets in near real time. In this article, we present a dictionary–based method to classify, by using AIS data, between two fishing gear types: trawl and purse seine. The data was obtained from Global Fishing Watch. Our experiments show that our proposal has a good performance in classifying fishing behaviors, which could help to prevent overexploit and improve the strategies of the fisheries management.

scholarly journals PENDEKATAN BIONOMI PADA PELUANG PENGEMBANGAN PERIKANAN TANGKAP DI KABUPATEN KEPULAUAN TALAUD

2012 ◽  
Vol 1 (2) ◽  
pp. 57
Author(s):  
Jeti Pulu ◽  
Mulyono S. Baskoro ◽  
Daniel R. Monintja ◽  
Budhi H. Iskandar ◽  
Akhmad Fauzi
Keyword(s):  
Open Access ◽  
Economic Value ◽  
Secondary Data ◽  
Primary Data ◽  
Fishing Gear ◽  
Fish Production ◽  
Resource Rent ◽  
Illegal Fishing ◽  
Fishing Gears ◽  
Catch Composition

The research is aimed to reveal opportunity development of the capture fisheries in Talaud Islands Regency by using bionomy approach with Gordon-Schaefer model (Fauzy, 2005) con-cerning the dominant of illegal fishing activities around the area. The research was started by co-llected some secondary data on fish production and number of fishing units. Primary data were collected on catch composition and types of fishing gear. Gordon-Schaefer methods was applied to evaluate the tuna and skipjack resources in the area. The troll and pole and line are indicated as the dominant fishing gears used to catch the skipjack and tuna. In case of open access condition, the production will end up to 25,09 tons, while the resource rent will be end up to zero. For the development, simulations were exercised in 3 scenarios: 1) scenario of enhancing domestic fleet, 2) scenario of illegal fishing, and 3) scenario of net surplus. With those scenarios, if the illegal fishing could be eliminated, the capture fisheries in this regency could render economic value to 10 billion rupiah.

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