How useful is the ratio of fish density outside versus inside no-take marine reserves as a metric for fishery management control rules?

2011 ◽  
Vol 68 (2) ◽  
pp. 343-359 ◽  
Author(s):  
Elizabeth A. Babcock ◽  
Alec D. MacCall
Keyword(s):  
Fishery Management ◽  
Spatial Scales ◽  
Marine Reserves ◽  
Density Ratio ◽  
Relative Weight ◽  
Fishing Effort ◽  
Management Control ◽  
Fish Density ◽  
Control Rules ◽  
Stock Depletion

A management strategy evaluation (based on five species in the California, USA, nearshore fishery) of control rules that reduce relative fishing effort as a function of the ratio of fish density outside versus inside no-take marine reserves (as a measure of depletion) showed that although the control rules allowed effort to increase at first, in the long term, they were effective at maintaining spawning stock biomass and yield for all simulated species, including depleted ones. Scenarios with fish movement, illegal fishing in the reserve, or post-dispersal density dependence in recruitment required higher density ratio targets, such as 60% of mature fish or 80% of all fish, to avoid stock depletion. The effort allowed by multispecies density-ratio control rules depended on the relative weight given to more or less depleted species. High variability in recruitment or in monitoring data caused the allowable effort to fluctuate. Density-ratio control rules have the advantages that they require no historical data, they can be used at local spatial scales, and they adjust to changing environmental conditions.

scholarly journals Linking spatial stock dynamics and economics: evaluation of indicators and fishery management for the travelling eastern king prawn (Melicertus plebejus)

2014 ◽  
Vol 71 (7) ◽  
pp. 1818-1834 ◽  
Author(s):  
Michael F. O'Neill ◽  
George M. Leigh ◽  
You-Gan Wang ◽  
J. Matías Braccini ◽  
Matthew C. Ives
Keyword(s):  
Fishery Management ◽  
New South ◽  
Fishing Effort ◽  
Reference Points ◽  
Catch Rate ◽  
Decision Makers ◽  
Control Rules ◽  
South Wales ◽  
Strategy Evaluation ◽  
Dynamics Calculation

Abstract Reduced economic circumstances have moved management goals towards higher profit, rather than maximum sustainable yields in several Australian fisheries. The eastern king prawn is one such fishery, for which we have developed new methodology for stock dynamics, calculation of model-based and data-based reference points and management strategy evaluation. The fishery is notable for the northward movement of prawns in eastern Australian waters, from the State jurisdiction of New South Wales to that of Queensland, as they grow to spawning size, so that vessels fishing in the northern deeper waters harvest more large prawns. Bioeconomic fishing data were standardized for calibrating a length-structured spatial operating model. Model simulations identified that reduced boat numbers and fishing effort could improve profitability while retaining viable fishing in each jurisdiction. Simulations also identified catch rate levels that were effective for monitoring in simple within-year effort-control rules. However, favourable performance of catch rate indicators was achieved only when a meaningful upper limit was placed on total allowed fishing effort. The methods and findings will allow improved measures for monitoring fisheries and inform decision makers on the uncertainty and assumptions affecting economic indicators.

scholarly journals High-seas fish wars generate marine reserves

2016 ◽  
Vol 113 (14) ◽  
pp. 3767-3772 ◽  
Author(s):  
Guillermo E. Herrera ◽  
Holly V. Moeller ◽  
Michael G. Neubert
Keyword(s):  
Fishery Management ◽  
Marine Reserves ◽  
Fishing Effort ◽  
Economic Benefits ◽  
Theoretic Model ◽  
Fish Stocks ◽  
Stock Size ◽  
Game Theoretic ◽  
Game Theoretic Model ◽  
High Seas

The effective management of marine fisheries is an ongoing challenge at the intersection of biology, economics, and policy. One way in which fish stocks—and their habitats—can be protected is through the establishment of marine reserves, areas that are closed to fishing. Although the potential economic benefits of such reserves have been shown for single-owner fisheries, their implementation quickly becomes complicated when more than one noncooperating harvester is involved in fishery management, which is the case on the high seas. How do multiple self-interested actors distribute their fishing effort to maximize their individual economic gains in the presence of others? Here, we use a game theoretic model to compare the effort distributions of multiple noncooperating harvesters with the effort distributions in the benchmark sole owner and open access cases. In addition to comparing aggregate rent, stock size, and fishing effort, we focus on the occurrence, size, and location of marine reserves. We show that marine reserves are a component of many noncooperative Cournot–Nash equilibria. Furthermore, as the number of harvesters increases, (i) both total unfished area and the size of binding reserves (those that actually constrain behavior) may increase, although the latter eventually asymptotically decreases; (ii) total rents and stock size both decline; and (iii) aggregate effort used (i.e., employment) can either increase or decrease, perhaps nonmonotonically.

scholarly journals Sustainable exploitation of temperate fish stocks

2009 ◽  
Vol 6 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Henrik Sparholt ◽  
Robin M. Cook
Keyword(s):  
Species Interactions ◽  
Fishery Management ◽  
Regional Scale ◽  
Single Species ◽  
Fishing Effort ◽  
Theoretical Concept ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
The Status ◽  
Long Time

The theory of maximum sustainable yield (MSY) underpins many fishery management regimes and is applied principally as a single species concept. Using a simple dynamic biomass production model we show that MSY can be identified from a long time series of multi-stock data at a regional scale in the presence of species interactions and environmental change. It suggests that MSY is robust and calculable in a multispecies environment, offering a realistic reference point for fishery management. Furthermore, the demonstration of the existence of MSY shows that it is more than a purely theoretical concept. There has been an improvement in the status of stocks in the Northeast Atlantic, but our analysis suggests further reductions in fishing effort would improve long-term yields.

scholarly journals The relative weight of traditions, economics, and catch plans in New Zealand fleet dynamics

2009 ◽  
Vol 66 (2) ◽  
pp. 291-311 ◽  
Author(s):  
Paul Marchal ◽  
Philippe Lallemand ◽  
Kevin Stokes
Keyword(s):  
New Zealand ◽  
Relative Weight ◽  
Fishing Effort ◽  
Expected Profit ◽  
Nested Logit ◽  
Individual Transferable Quota ◽  
Management Regime ◽  
One Year ◽  
Fleet Dynamics ◽  
Statistical Area

We investigate the relative weights of catch plans, expected profit, and traditions in fishers’ decision-making for five New Zealand fleets subject to an individual transferable quota (ITQ) management regime. Métiers were defined for these fleets as a combination of gears, management units, and a targeting index (either target species or statistical area). A nested logit random utility model was used to model the métier allocation of fishing effort in relation to catch plans, expected profit, and past fishing allocations. This study showed that traditions and catch plans appeared to be important determinants of fishers’ behavior for these New Zealand fleets. The model developed in this study fitted the data generally well and was also able to predict, in most cases, future effort allocation both one month and one year ahead.

scholarly journals Wavelet-based spatial comparison technique for analysing and evaluating two-dimensional geophysical model fields

2012 ◽  
Vol 5 (1) ◽  
pp. 223-230 ◽  
Author(s):  
S. Saux Picart ◽  
M. Butenschön ◽  
J. D. Shutler
Keyword(s):  
Satellite Data ◽  
Fishery Management ◽  
Numerical Models ◽  
Spatial Scales ◽  
Marine Ecosystem ◽  
Original Method ◽  
Precipitation Forecast ◽  
Spatial And Temporal Scales ◽  
Geographical Patterns ◽  
Marine Ecosystem Model

Abstract. Complex numerical models of the Earth's environment, based around 3-D or 4-D time and space domains are routinely used for applications including climate predictions, weather forecasts, fishery management and environmental impact assessments. Quantitatively assessing the ability of these models to accurately reproduce geographical patterns at a range of spatial and temporal scales has always been a difficult problem to address. However, this is crucial if we are to rely on these models for decision making. Satellite data are potentially the only observational dataset able to cover the large spatial domains analysed by many types of geophysical models. Consequently optical wavelength satellite data is beginning to be used to evaluate model hindcast fields of terrestrial and marine environments. However, these satellite data invariably contain regions of occluded or missing data due to clouds, further complicating or impacting on any comparisons with the model. This work builds on a published methodology, that evaluates precipitation forecast using radar observations based on predefined absolute thresholds. It allows model skill to be evaluated at a range of spatial scales and rain intensities. Here we extend the original method to allow its generic application to a range of continuous and discontinuous geophysical data fields, and therefore allowing its use with optical satellite data. This is achieved through two major improvements to the original method: (i) all thresholds are determined based on the statistical distribution of the input data, so no a priori knowledge about the model fields being analysed is required and (ii) occluded data can be analysed without impacting on the metric results. The method can be used to assess a model's ability to simulate geographical patterns over a range of spatial scales. We illustrate how the method provides a compact and concise way of visualising the degree of agreement between spatial features in two datasets. The application of the new method, its handling of bias and occlusion and the advantages of the novel method are demonstrated through the analysis of model fields from a marine ecosystem model.

scholarly journals Factors affecting relative abundance of low-mobility fishing resources: spiny lobster in the Galapagos Marine Reserve

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7278 ◽  
Author(s):  
Juan Carlos Murillo-Posada ◽  
Silvia Salas ◽  
Iván Velázquez-Abunader
Keyword(s):  
Monitoring System ◽  
Relative Abundance ◽  
Spatial Scales ◽  
Marine Reserve ◽  
Spiny Lobster ◽  
Fishing Effort ◽  
Additive Models ◽  
Catch Per Unit Effort ◽  
Monthly Basis ◽  
Galapagos Marine Reserve

Management of low-mobility or benthic fisheries is a difficult task because variation in the spatial distribution and population dynamics of the resources make the monitoring and assessment of these fisheries challenging. We assumed that environmental, spatial, and temporal factors can contribute to the variability of the relative abundance of such species; we used Generalized Additive Models for Location Scale and Shape (GAMLSS) to test this hypothesis using as a case study the lobster fishery (targeting two species) in the Galapagos Marine Reserve, Ecuador. We gathered data on each of the two species of lobster on a monthly basis over seven years, including: (a) onboard observers’ records of catch data, fishing effort, and ground location by trip, and (b) data from interviews undertaken with fishers at their arrival to port, recording the same type of information as obtained from onboard observers. We use this information to analyze the effect of the measured variables and to standardize the Catch per Unit Effort (CPUE) in each case, using the GAMLSS. For both species, the temperature, region, fishing schedule, month, distance, and the monitoring system were significant variables of the selected models associated with the variability of the catch rate. ForPanulirus penicillatus, CPUE was higher at night than during the day, and forPanulirus gracilisit was higher during the day. Increased temperature resulted in a decrease of CPUE values. It was evident that temporal, spatial scales and monitoring system can influence the variability of this indicator. We contend that the identification of drivers of change of relative abundance in low-mobility species can help to support the development of monitoring and assessment programs for this type of fisheries.

scholarly journals CONFOUNDING EFFECTS OF THE EXPORT OF PRODUCTION AND THE DISPLACEMENT OF FISHING EFFORT FROM MARINE RESERVES

2004 ◽  
Vol 14 (4) ◽  
pp. 1248-1256 ◽  
Author(s):  
Benjamin S. Halpern ◽  
Steven D. Gaines ◽  
Robert R. Warner
Keyword(s):  
Marine Reserves ◽  
Fishing Effort

scholarly journals Sensing the Same Fishing Fleet with AIS and VIIRS: A Seven-Year Assessment of Squid Jiggers in FAO Major Fishing Area 41

2019 ◽  
Vol 12 (1) ◽  
pp. 32
Author(s):  
Javier Ruiz ◽  
Isabel Caballero ◽  
Gabriel Navarro
Keyword(s):  
Infrared Imaging ◽  
Spatial Scales ◽  
Fishing Effort ◽  
Automatic Identification ◽  
Identification System ◽  
Sources Of Information ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
High Degree ◽  
Fishing Area

Global Fishing Watch and VIIRS-DNB (visible infrared imaging radiometer suite day/night band) signals are compared for the jigger fleet in FAO (Food and Agriculture Organization of the United Nations) Major Fishing Area 41 during the maximum feasible time span (2012–2018). Both signals have shown a high degree of consistency at all temporal and spatial scales analyzed, including seasonal cycles, lack of signal for some years and interannual tendencies. This indicates that both signals are a fair representation of the fishing effort exerted by the jigger fleet in this zone. The high degree of consistency does not support views questioning satellite AIS (automatic identification system) as a reliable tool to survey fishing activities. Instead, our results add evidence supporting the value of remote sensing, in particular, when independent sources of information (such as VIIRS-DNB and AIS) are combined, as a relevant tool to add transparency and support compliance of fishing activities in vast and distant regions of the ocean.

Persistence in the fine-scale distribution and spatial aggregation of fishing

2018 ◽  
Vol 76 (4) ◽  
pp. 1072-1082 ◽  
Author(s):  
Niels T Hintzen ◽  
Geert Aarts ◽  
Adriaan D Rijnsdorp
Keyword(s):  
High Stability ◽  
Large Scale ◽  
Spatial Scales ◽  
Negative Relationship ◽  
Fishing Effort ◽  
Local Scale ◽  
Fine Scale ◽  
Effort Allocation ◽  
The Stability ◽  
First Time

Abstract High-resolution vessel monitoring (VMS) data have led to detailed estimates of the distribution of fishing in both time and space. While several studies have documented large-scale changes in fishing distribution, fine-scale patterns are still poorly documented, despite VMS data allowing for such analyses. We apply a methodology that can explain and predict effort allocation at fine spatial scales; a scale relevant to assess impact on the benthic ecosystem. This study uses VMS data to quantify the stability of fishing grounds (i.e. aggregated fishing effort) at a microscale (tens of meters). The model links effort registered at a large scale (ICES rectangle; 1° longitude × 0.5° latitude, ˜3600 km2) to fine spatial trawling intensities at a local scale (i.e. scale matching gear width, here 24 m). For the first time in the literature, the method estimates the part of an ICES rectangle that is unfavourable or inaccessible for fisheries, which is shown to be highly stable over time and suggests higher proportions of inaccessible grounds for either extremely muddy or courser substrates. The study furthermore shows high stability in aggregation of fishing, where aggregation shows a positive relationship with depth heterogeneity and a negative relationship with year-on-year variability in fishing intensity.

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