scholarly journals Competition between static gear of the small-scale fisheries in Algarve waters (southern Portugal)

2010 ◽  
Vol 11 (2) ◽  
pp. 225 ◽  
Author(s):  
K. ERZINI ◽  
J.M.S. GONCALVES ◽  
L. BENTES ◽  
P.G. LINO ◽  
J. RIBEIRO ◽  
...  
Keyword(s):  
Species Composition ◽  
Fishing Effort ◽  
Small Scale ◽  
Gill Nets ◽  
Scarce Resources ◽  
Small Scale Fisheries ◽  
Southern Portugal ◽  
Catch Rates ◽  
One Year ◽  
And Control

Parallel fishing trials with 0.30 mm diameter monofilament gill nets and longlines using small hooks were carried out in the Algarve (southern Portugal) over a one-year period, 1997-1998, with the objective of comparing species composition, catch rates, discards and size ranges. Four hook sizes of 'Mustad' brand, round bent, flatted sea hooks (numbers 15, 13, 12 and 11) and four mesh sizes of 25, 30, 35 and 40 mm (nominal bar length) of gill nets were used in the trials. Overall, 84 species were caught, with gill nets taking 71 species and longlines 54 species and with 41 species caught by both gears. The amount of discarding was higher for gill nets than for longlines. The catch species composition differed between the two gears, with the commercially valuable sea breams dominating the longline catches whereas small pelagics were relatively more important in the gill nets. Multivariate analysis showed a clear separation between the different sizes of the two gears both in terms of numbers and weights per species. Algarve gill netters and longliners fish the same species assemblage on the same fishing grounds, but have clearly different impacts in terms of catch species composition, catch rates and sizes. This information will be useful for the improved management of these small-scale, multi-species, multi-gear fisheries, where different gears compete for scarce resources. In particular this study provides a basis for a more rational allocation of licenses and control of fishing effort.

scholarly journals Risk tolerance and control perception in a game-theoretic bioeconomic model for small-scale fisheries

2020 ◽  
Vol 7 (7) ◽  
pp. 200621
Author(s):  
Eric Zettermann Dias de Azevedo ◽  
David Valença Dantas ◽  
Fábio G. Daura-Jorge
Keyword(s):  
Evolutionary Game ◽  
Fishing Effort ◽  
Risk Tolerance ◽  
Sensitivity Analyses ◽  
Small Scale ◽  
Individual Level ◽  
Small Scale Fisheries ◽  
Game Theoretic ◽  
And Control ◽  
Two Populations

Cooperation is generally the most advantageous strategy for the group; however, on an individual level, cheating is frequently more attractive. In a fishery, one can choose to cooperate by fishing only the regulated amount or not to cooperate, by fishing to maximize profits. Top-down management can help to emulate a cooperative result in fisheries, but it is costly and not always a viable alternative for development states. Here, we investigate elements of a fishing system that can be strategically managed to encourage a cooperative behaviour. Using bioeconomic data, we modelled an evolutionary game between two populations of fishers that differ if they cooperate or do not cooperate with a fishing restriction. We penalized players including risk tolerance and control perception, two social parameters that might favour cooperation. We assessed the degrees to which risk tolerance and control perception affect the cooperative behaviours of fishers in a restricted fishing effort small-scale fishery (RSSF) in southern Brazil. We also assessed the likelihood of a scenario wherein a cooperative strategy can evolve and dominate the system. We identified dominance and coexistence outcomes for the RSSF. Sensitivity analyses suggested that both control perception and risk tolerance could facilitate a cooperative outcome for the fishery.

scholarly journals Technical measures without enforcement tools: is there any sense? A methodological approach for the estimation of passive net length in small scale fisheries

2014 ◽  
Vol 16 (1) ◽  
pp. 82 ◽  
Author(s):  
A. LUCCHETTI ◽  
G. BUGLIONI ◽  
A. CONIDES ◽  
D. KLAOUDATOS ◽  
P. SARTOR ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Fishing Effort ◽  
Management Tool ◽  
Small Scale ◽  
Strongly Correlated ◽  
Small Scale Fisheries ◽  
Length Estimation ◽  
Fishing Gears ◽  
And Control ◽  
Technical Measures

Passive nets are currently among the most important fishing gears largely used along the Mediterranean coasts by the small scale fisheries sector. The fishing effort exerted by this sector is strongly correlated with net dimensions. Therefore, the use of passive nets is worldwide managed by defining net length and net drop. The EC Reg. 1967/2006 reports that the length of bottom-set and drifting nets may be also defined considering their weight or volume; however, no practical suggestions for fisheries inspectors are yet available. Consequently,  even if such technical measures are reasonable from a theoretical viewpoint, they are hardly suitable as a management tool, due to the difficulties in harbour control. The overall objective of this paper is to provide a quick methodological approach for the gross estimation of passive net length (by net type) on the basis of net volume. The final goal is to support fisheries managers with suitable advice for enforcement and control purposes. The results obtained are important for the management of the fishing effort exerted by small scale fisheries. The methodology developed in this study should be considered as a first attempt to tackle the tangled problem of net length estimation that can be easily applied in other fisheries and areas in order to improve the precision of the models developed herein.

scholarly journals Using pingers to reduce bycatch of small cetaceans in Peru's small-scale driftnet fishery

Oryx ◽  
2013 ◽  
Vol 47 (4) ◽  
pp. 595-606 ◽  
Author(s):  
Jeffrey C. Mangel ◽  
Joanna Alfaro-Shigueto ◽  
Matthew J. Witt ◽  
David J. Hodgson ◽  
Brendan J. Godley
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Marine Fauna ◽  
Incidental Capture ◽  
Small Scale Fisheries ◽  
Control Sets ◽  
Northern Peru ◽  
Catch Rates

AbstractThere is growing awareness that small-scale fisheries may have large impacts on threatened marine fauna. Bycatch of small cetaceans by the Peruvian small-scale driftnet fleet results in the deaths of thousands of animals annually. We sought to assess the effectiveness of acoustic alarms (pingers) for reducing the incidental capture of dolphins and porpoises by this fleet. Forty-three experimental trips (156 fishing sets) and 47 control trips (195 fishing sets) out of Salaverry Port, northern Peru, were observed from April 2009 to August 2011. Twenty-two percent of control sets captured small cetaceans (67 individuals) and 16% of experimental sets had captures of small cetaceans (33 individuals). The bycatch rate of experimental sets was 0.50 individuals km−2h−1, whereas for control sets the rate was 0.80 individuals km−2h−1. This 37% reduction in bycatch rate suggests that pingers may be effective in reducing the bycatch of small cetaceans in this fishery. Catch rates of the fishery's target shark and ray species were unchanged. Given the vast size of this fishery and its current levels of bycatch of small cetaceans (> 10,000 individuals annually), even the modest declines in bycatch we observed could result in reductions in mortality of hundreds or thousands of small cetaceans per annum. Challenges, including increased costs, to large-scale utilization of pingers have yet to be overcome. The harpooning of dolphins for use as bait will also need to be addressed for further reductions in dolphin and porpoise bycatch and mortality to be achievable.

scholarly journals A Bio-Economic Analysis of the Liberian Coastal Fisheries

2020 ◽  
Vol 12 (23) ◽  
pp. 9848
Author(s):  
Alvin Slewion Jueseah ◽  
Dadi Mar Kristofersson ◽  
Tumi Tómasson ◽  
Ogmundur Knutsson
Keyword(s):  
New Technologies ◽  
Fishing Effort ◽  
Small Scale ◽  
Exclusion Zone ◽  
Coastal Fisheries ◽  
Small Scale Fisheries ◽  
Species Complexes ◽  
Limited Enforcement ◽  
Dugout Canoes ◽  
The Government

Many coastal fisheries are subject to harvesting externalities due to inadequate regulations compounded by limited enforcement. Coastal fisheries in Liberia consist of a fleet of dugout canoes (Kru) primarily targeting demersal finfish, larger open wooden boats propelled with outboard engines targeting small inshore pelagics (Fanti), and a small number of industrial trawlers employing midwater and bottom trawls targeting finfish and shrimp. This paper develops a bio-economic model for the coastal fisheries in Liberia and employs the model to identify economic optimal fishing effort and harvesting trajectories for the different coastal fleets. The results show under harvesting and disinvestments in the coastal fisheries in Liberia. In 2010 the Government of Liberia declared a six nautical mile inshore exclusion zone accessible only to small-scale fisheries (SSF), which was accompanied by increased enforcement. The coastal fleets in 2016 were profitable but the distribution of profits was tilted to the small-scale fleets. The government needs to evaluate what policy options are available to fully utilize the fisheries potential for different species complexes while at the same time reduce the risk of conflict and overharvesting. There appears to be a need for investment in new technologies, which can only take place if fishing in Liberia will remain profitable.

Use of Oceanographic Forecasts and Echosounders to Guide and Enhance an Inshore Gillnet Fishery for Atlantic Cod (Gadus morhua)

1993 ◽  
Vol 50 (10) ◽  
pp. 2129-2136 ◽  
Author(s):  
G. A. Rose ◽  
W.C. Leggett
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fishing Effort ◽  
Shallow Waters ◽  
Gill Nets ◽  
Rule Of Thumb ◽  
Combined Use ◽  
Catch Rates ◽  
Depth Ranges ◽  
High Fish

Vessels fishing with gill nets for Atlantic cod (Gadus morhua) in the northern Gulf of St. Lawrence in 1985 and 1986 concentrated their fishing effort in shallow waters (<50 m) where cod densities were highest (to 0.5/m3). In both years, seasonal trends (June–August) in mean daily deployment depths of gill nets were positively correlated with mean depths at which cod were surveyed (1985, r = 0.71; 1986, r = 0.51, Ps < 0.05). Daily catch rate variability of individual vessels was accounted for by fish "flux" adjacent to nets (44%), vessel operator skill (19%), and "flux"–skill interaction (8%; total R2 = 0.71). A guided vessel directed to fish at sites predicted to have high fish flux (located down-current from high-density cod aggregations identified by echosounding within depth ranges forecast to be favorable to cod by "rule of thumb" wind-based oceanographic models) had higher catch rates (mean 1.3 t/d) than the fleet average and its own average fishing without guidance (means 0.4 t/d, P's < 0.05). Directed searches were of shorter duration (mean 0.5 h) than searches conducted at random (1.5 h). Combined use of echosounders and air–sea-based forecasts of cod distribution could help stabilize catch rates, especially at times of poor fish availability inshore.

scholarly journals Combining participatory and socioeconomic approaches to map fishing effort in small-scale fisheries

PLoS ONE ◽  
2017 ◽  
Vol 12 (5) ◽  
pp. e0176862 ◽  
Author(s):  
Lauric Thiault ◽  
Antoine Collin ◽  
Frédérique Chlous ◽  
Stefan Gelcich ◽  
Joachim Claudet
Keyword(s):  
Fishing Effort ◽  
Small Scale ◽  
Small Scale Fisheries

Characterisation, analysis and catch rates of the small-scale fisheries of the Alicante Gulf (SE Spain) over a 10 years time series

2006 ◽  
Vol 77 (2) ◽  
pp. 226-238 ◽  
Author(s):  
Mariano García-Rodríguez ◽  
Ángel M. Fernández ◽  
Antonio Esteban
Keyword(s):  
Time Series ◽  
Small Scale ◽  
Se Spain ◽  
Small Scale Fisheries ◽  
Catch Rates

scholarly journals PeskAAS: A near-real-time, open-source monitoring and analytics system for small-scale fisheries

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0234760
Author(s):  
Alexander Tilley ◽  
Joctan Dos Reis Lopes ◽  
Shaun P. Wilkinson
Keyword(s):  
Open Source ◽  
Source Monitoring ◽  
R Package ◽  
Small Island ◽  
Small Scale ◽  
Small Scale Fisheries ◽  
Fish Catch ◽  
Catch Rates ◽  
Context Specific ◽  
Species Specific

Small-scale fisheries are responsible for landing half of the world’s fish catch, yet there are very sparse data on these fishing activities and associated fisheries production in time and space. Fisheries-dependent data underpin scientific guidance of management and conservation of fisheries systems, but it is inherently difficult to generate robust and comprehensive data for small-scale fisheries, particularly given their dispersed and diverse nature. In tackling this challenge, we use open source software components including the Shiny R package to build PeskAAS; an adaptable and scalable digital application that enables the collation, classification, analysis and visualisation of small-scale fisheries catch and effort data. We piloted and refined this system in Timor-Leste; a small island developing nation. The features that make PeskAAS fit for purpose are that it is: (i) fully open-source and free to use (ii) component-based, flexible and able to integrate vessel tracking data with catch records; (iii) able to perform spatial and temporal filtering of fishing productivity by fishing method and habitat; (iv) integrated with species-specific length-weight parameters from FishBase; (v) controlled through a click-button dashboard, that was co-designed with fisheries scientists and government managers, that enables easy to read data summaries and interpretation of context-specific fisheries data. With limited training and code adaptation, the PeskAAS workflow has been used as a framework on which to build and adapt systematic, standardised data collection for small-scale fisheries in other contexts. Automated analytics of these data can provide fishers, managers and researchers with insights into a fisher’s experience of fishing efforts, fisheries status, catch rates, economic efficiency and geographic preferences and limits that can potentially guide management and livelihood investments.

scholarly journals Fishing Effort and Associated Catch per Unit Effort for Small-Scale Fisheries in the Mozambique Channel Region: 1950–2016

2021 ◽  
Vol 8 ◽  
Author(s):  
Dirk Zeller ◽  
Gabriel M. S. Vianna ◽  
Matthew Ansell ◽  
Angie Coulter ◽  
Brittany Derrick ◽  
...  
Keyword(s):  
Fishing Effort ◽  
Small Scale ◽  
Catch Per Unit Effort ◽  
Important Species ◽  
Small Scale Fisheries ◽  
Mozambique Channel ◽  
Fishing Vessels ◽  
Unit Effort ◽  
Fishing Capacity ◽  
Channel Region

The Mozambique Channel region in East Africa has diverse marine ecosystems and serves as a migratory corridor for economically important species. Local and foreign industrial fisheries operate in the Mozambique Channel, but regional small-scale fisheries are the crucially important fisheries that provide food security, livelihoods, and economic opportunities for rural coastal communities. This study reconstructed and investigated trends in the fishing effort and catch per unit effort (CPUE) of small-scale marine fisheries in four Exclusive Economic Zones (EEZ) that constitute the Mozambique Channel, i.e., Union of Comoros, Madagascar, Mayotte, and Mozambique, from 1950 to 2016. Effective fishing effort for small-scale fisheries in the form of fishing capacity in kWdays (i.e., kilowatt days) was derived using the number, length, motorization (engine power) by fishing vessels, as well as an approximate human-powered equivalent for shore-based fishers without vessels, as well as days of fishing per year. Effective small-scale fishing effort in the Mozambique Channel increased by nearly 60 times from just over 386,000 kWdays in 1950 to over 23 million kWdays in 2016. Correspondingly, the overall small-scale CPUE, based on previously and independently reconstructed catch data declined by 91% in the region as a whole, from just under 175 kg⋅kWday–1 in the early 1950s to just over 15 kg⋅kWday–1 in recent years. All four EEZs showed the strongest declines in the small-scale CPUE in the earlier decades, driven by motorization and growth in vessel numbers impacting effective fishing effort. Increased motorization combined with a substantial growth in overall vessel numbers were the drivers of the increasing fishing effort and decreasing CPUE, and clearly suggest that continuing to increase the fishing capacity of small-scale fisheries in the absence of effective and restrictive management actions may exacerbate overexploitation risk.

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