scholarly journals Danger beyond the catches: a review of conservation threats posed by commercial and non-commercial fisheries in Guaratuba Bay, southern Brazil

2020 ◽  
Author(s):  
P. T. C. Chaves
Keyword(s):  
Critical Size ◽  
Fishing Effort ◽  
Shallow Waters ◽  
Commercial Fisheries ◽  
Southern Brazil ◽  
Recreational Fisheries ◽  
Catch And Release ◽  
Fishing Gears ◽  
Popular View ◽  
Conservation Threats

Abstract Comparisons between the implications of commercial and recreational fisheries for estuarine conservation have been a topic of debate. A review on the available data from Guaratuba Bay, Southern Brazil, identifies six threats for conservation, other than those concerning the fishing effort on target resources. Differing from the popular view that fishing for pleasure could be innocuous for the environment, the identified threats concern both commercial and non-commercial fisheries: (1) catching of reproductive individuals; (2) catch of big old fat fecund females; (3) loss and abandonment of fishing gears; (4) use of natural baits; (5) bycatch of rays, turtles and non-target finfish; and (6) bad practices associated with catch-and-release or discarding. Environmental disturbances and fauna depletion are detected as potential impacts. Recommended actions for estuary conservation include fishing closures in mangrove and shallow waters areas, release of fish larger than the critical size, and measures against abandoned, lost or otherwise discarded fishing gears.

Efficiency and selectivity of the Anomalocardia brasiliana (Mollusca: Veneridae) hand dredge used in southern Brazil

2010 ◽  
Vol 90 (7) ◽  
pp. 1455-1464 ◽  
Author(s):  
Paulo R. Pezzuto ◽  
Caroline Schio ◽  
Tito C.M. Almeida
Keyword(s):  
Management Plan ◽  
Fishing Effort ◽  
Management Tool ◽  
Small Scale ◽  
Commercial Fisheries ◽  
Effective Management ◽  
Southern Brazil ◽  
Fishing Rights ◽  
Before And After ◽  
Experimental Plots

In Florianópolis, southern Brazil, the venerid clam Anomalocardia brasiliana has supported subsistence and small-scale commercial fisheries for decades. The introduction of a hand dredge (gancho) since 1987 led to the development of a significant fishery supplying both local and regional shellfish markets. In 1992 one of the main fishing areas in the region was designated as the first Brazilian Marine Extractive Reserve (Pirajubaé RESEX), a federal form of governance intended to promote sustainable exploitation of natural resources by assigning exclusive fishing rights to traditional users. However, excessive fishing effort, institutional shortcomings and lack of a negotiated management plan have resulted in the overexploitation of the species since 2000. This study was aimed at evaluating the efficiency and selectivity of the hand dredge currently in use at the RESEX, through a field experiment conducted in October 2006. Quantitative samples of A. brasiliana were collected before and after dredging 15 experimental plots. Additional samples were obtained inside the dredge (catch) and respective cover cod-end (discard) for selectivity analysis. A single haul of the hand dredge can dislocate up to 76% of the individuals present in the sediment irrespective of their size, and retain up to 69% of the commercial-sized organisms. The gear has a knife-edge selection pattern, which enables the use of the minimum spacing between the iron bars of the dredge's basket as an effective management tool.

Recreational Fishing

2019 ◽  
pp. 83-91
Author(s):  
Ray Hilborn ◽  
Ulrike Hilborn
Keyword(s):  
Economic Value ◽  
Developed Countries ◽  
Fishing Effort ◽  
Recreational Fishing ◽  
Commercial Fisheries ◽  
Recreational Fisheries ◽  
The World ◽  
The Developed Countries ◽  
Do So

Recreational Fishing. Recreational fisheries involve far more people than commercial fisheries do in most of the developed countries, and their economic value is often estimated to be larger than that of commercial fisheries. The main objective of most recreational fisheries is the opportunity to fish rather than the number or value of fish caught, and very different management methods are appropriate. Ideally, the total fishing effort should be maximized rather than reduced, to keep costs down as for commercial fisheries. Access to recreational fishing differs greatly around the world and ranges from effectively privatizing fishing opportunity to allowing anyone wishing to fish to do so.

Statistical Bias Problem in On-Site Surveys: the Severity of the Problem and its Potential for Solution

1975 ◽  
Vol 32 (12) ◽  
pp. 2520-2524
Author(s):  
William F. Sinclair ◽  
R. W. Morley
Keyword(s):  
Fishing Effort ◽  
Recreational Fisheries ◽  
Statistical Bias ◽  
Relative Probability ◽  
Fishing Vessels ◽  
Frequency Of Use ◽  
Unbiased Estimates ◽  
Weighting Procedures ◽  
Use Category

Commercial and recreational fisheries managers often develop catch and effort estimates from information gathered in location or on-site surveys. However, a limited on-site sample cannot produce unbiased estimates of fishing effort or socioeconomic traits of the anglers unless weighting procedures are adopted to account for the varying frequencies of fishing of the fishermen. The corrective procedure involves establishing the relative probability of capturing a fisherman in the sample, then weighting the number of contacts with anglers in each frequency of use category. Unless information on the probability of including particular fishermen and fishing vessels in the sample is available the sample must be drawn with replacement.

scholarly journals Numerical Model of Fish Exploitation – structure and application

2019 ◽  
Vol 27 (2) ◽  
pp. 86-101
Author(s):  
Paweł Buras ◽  
Wiesław Wiśniewolski
Keyword(s):  
Numerical Model ◽  
Simulation Models ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Recreational Fisheries ◽  
Fisheries Resources ◽  
Fish Exploitation ◽  
The Common ◽  
Common Bream ◽  
The Impact

Abstract Fisheries simulation models are tools used for forecasting the effects of exploitation and determining the directions of managing fisheries resources. The Numerical Model of Fish Exploitation (NMFE) and its capabilities were tested on a population of common bream, Abramis brama (L.) in a dam reservoir that is exploited by commercial and recreational fisheries. Based on the designated population parameters of N0, Fij, Mi, and ei and the size and structure of the common bream population in the reservoir, the model was used to examine hypothetical simulation variants of changes in fishing intensity E1 with nets and rods, changes in fishing intensity based on actual fishing effort with nets, changes in natural mortality, changes in the size of fish caught, and the impact of this on the size of the resources. Initial catches with nets and rods were calculated. Increasing fishing effort did not translate proportionally to increased catches, and the function was curvilinear. The results of simulations that reduced the intensity of fishing with nets and decreased catch sizes concurred with data from actual catches. Simulations of changes in natural mortality had various effects on the size of catches. Reducing parameter M did not impact the level of catches, while increasing parameter M reduced the size of catches significantly.

Analysis of crab size structure and the fishing effort applied to a crab fishery in northwest Mexico

Crustaceana ◽  
2018 ◽  
Vol 91 (2) ◽  
pp. 225-237 ◽  
Author(s):  
César A. Heredia-Delgadillo ◽  
Guillermo Rodríguez-Domínguez ◽  
Raúl Pérez-González ◽  
Nicolás Castañeda-Lomas ◽  
Sergio G. Castillo-Vargasmachuca ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Size Structure ◽  
Coastal Lagoons ◽  
Low Frequency ◽  
Fishing Effort ◽  
Double Ring ◽  
Northwest Mexico ◽  
Fishing Gears ◽  
Fishery Cooperatives ◽  
Ring Net

The fishing effort of a Sinaloa crab fishery in the Gulf of California in 2014 was analysed based on fishermen’s interviews, official catches and permits, and information from a sample of fishing logbooks from five fishery cooperatives operating in four coastal lagoons that contained the daily catch from individual fishing trips. Unauthorized gear, a double-ring net (DR), was used most frequently (>70% of the fishers) for crab fishing, although authorized single-ring nets and Chesapeake traps (CT) were also used with low frequency. The estimated fishing effort was 641 boats/day in the four coastal lagoons, which was 34% more than authorized, and 818 boats/day were employed in all of Sinaloa. A total of 57 479 fishing gears were estimated for the study area, which was 49.9% greater than the maximum authorized number, and 80 822 nominal fishing gears were estimated for the entire Sinaloa crab fishery, 14.15% more than the total gear limit (70 800). The size of the mesh used in the gear was smaller than the authorized limit of 76 mm, and >50% of the catches included crabs of unlawful size. It is argued that the effort must be regulated in terms of the number of vessels, per unit time, and not the number of gears. The information from this study demonstrates a failure to monitor compliance with current regulations and thus means that other strategies for the sustainable management of the fishery, such as co-management, should be tested.

Effects of gear type, entrance size and soak time on trap efficiency for freshwater crayfish Cherax destructor and C. albidus

2015 ◽  
Vol 66 (11) ◽  
pp. 989
Author(s):  
Paul Brown ◽  
Taylor L. Hunt ◽  
Khageswor Giri
Keyword(s):  
Field Experiments ◽  
Freshwater Crayfish ◽  
Recreational Fisheries ◽  
Air Breathing ◽  
Fixed Ring ◽  
Cherax Destructor ◽  
Fishing Gears ◽  
Opera House ◽  
By Catch ◽  
Aquatic Mammals

Freshwater crayfish support significant commercial and recreational fisheries worldwide. The genus Cherax is fished in Australia with a variety of fishing gears, yet little is known of the relative efficiency of the different fishing gears and methods. Additionally, freshwater-crayfish traps can pose a risk to air breathing by-catch such as aquatic mammals, reptiles and birds, so by-catch mitigation is important. We sought to understand whether freshwater-crayfish fishing can be undertaken efficiently, using passive traps and nets, without undue risk to air-breathing by-catch species. In field-experiments, we compared the efficiency of six gear types and tested the effect of five exclusion rings on catch performance over three soak times. The efficiency of gear types varied significantly by soak times. In productive locations, catch can be maximised by repeatedly deploying open-topped gear for short soak times. Opera-house traps fitted with fixed entrance rings (45–85-mm diameter) were not size-selective for yabbies. Encouragingly, open-topped gear and opera-house traps fitted with fixed ring entrances much smaller than many commercially available (45-mm diameter) still fish effectively for yabbies. We believe that smaller fixed ring-entrance size is likely to be correlated with a reduced risk of by-catch for air-breathing fauna.

Keepemwet Fishing—An emerging social brand for disseminating best practices for catch-and-release in recreational fisheries

2018 ◽  
Vol 205 ◽  
pp. 52-56 ◽  
Author(s):  
Andy J. Danylchuk ◽  
Sascha Clark Danylchuk ◽  
Andrew Kosiarski ◽  
Steven J. Cooke ◽  
Bryan Huskey
Keyword(s):  
Best Practices ◽  
Recreational Fisheries ◽  
Catch And Release
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