Modeling no-take marine reserves in regulated fisheries: assessing the role of larval dispersal

2008 ◽  
Vol 65 (11) ◽  
pp. 2509-2523 ◽  
Author(s):  
Carey R. McGilliard ◽  
Ray Hilborn
Keyword(s):  
Larval Dispersal ◽  
Marine Reserves ◽  
Dispersal Distance ◽  
Maximum Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Long Distance ◽  
Total Allowable Catch ◽  
Dispersal Distances ◽  
The Impact

We explored the effects of larval dispersal distance on the impact of no-take marine reserves (NTMRs) implemented in fisheries with catch regulations. NTMRs exist in many fisheries with harvest regulated by annual catch limits. In these fisheries, catch is taken from outside NTMRs, potentially resulting in reduced abundance outside NTMRs and an overall reduction in catch. We used a spatial model with two life stages (larvae and adults) to evaluate the effects of larval dispersal distance for fisheries managed by a total allowable catch (TAC) and an NTMR. We examined effects of the timing of density-dependent mortality in relation to larval movement. Abundance reached similar values for populations with long and short larval dispersal distances. Catch declined substantially for stocks with short larval dispersal distances. When larval dispersal distances were long, catch declined to values below maximum sustainable yield (MSY), but stabilized. Catch per unit effort (CPUE) declined to 9% of CPUE at MSY for stocks with short distance larval dispersal after the implementation of an NTMR; with long distance larval dispersal, CPUE declined to approximately 50% or less of the CPUE at MSY. The CPUE did not reflect trends in abundance after the implementation of an NTMR.

Integrating marine protected areas with catch regulation

2006 ◽  
Vol 63 (3) ◽  
pp. 642-649 ◽  
Author(s):  
Ray Hilborn ◽  
Fiorenza Micheli ◽  
Giulio A De Leo
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Larval Dispersal ◽  
Single Species ◽  
Maximum Sustainable Yield ◽  
Fish Stock ◽  
Total Allowable Catch ◽  
Fish Stocks ◽  
The Impact ◽  
Stock Abundance

Previous models of marine protected areas (MPAs) have generally assumed that there were no existing regulations on catch and have frequently shown that MPAs, by themselves, can be used to maintain both sustainable fish stocks and sustainable harvests. We explore the impact of implementing an MPA in a spatially structured model of a single-species fish stock that is regulated by total allowable catch (TAC). We find that when a stock is managed at maximum sustainable yield, or is overfished, implementation of an MPA will require a reduction in TAC to avoid increased fishing pressure on the stock outside the MPA. In both cases, catches will be lower as a result of overlaying an MPA on existing fisheries management. Only when the stock is so overfished that it is headed towards extinction does an MPA not lead to lower catches. In a TAC-regulated fishery, even if the stock is overfished, MPA implementation may not improve overall stock abundance or increase harvest unless catch is simultaneously reduced in the areas outside the MPA. Models that consider differential adult and larval dispersal need to be explored to see if these results are found with the more complex biology of a two-stage model.

scholarly journals Probability of successful larval dispersal declines fivefold over 1 km in a coral reef fish

2011 ◽  
Vol 279 (1735) ◽  
pp. 1883-1888 ◽  
Author(s):  
Peter M. Buston ◽  
Geoffrey P. Jones ◽  
Serge Planes ◽  
Simon R. Thorrold
Keyword(s):  
Larval Dispersal ◽  
Isolation By Distance ◽  
Dispersal Distance ◽  
Population Connectivity ◽  
Marine Ecology ◽  
Sea Anemones ◽  
Marine Population ◽  
Amphiprion Percula ◽  
Distance Distributions ◽  
Dispersal Distances

A central question of marine ecology is, how far do larvae disperse? Coupled biophysical models predict that the probability of successful dispersal declines as a function of distance between populations. Estimates of genetic isolation-by-distance and self-recruitment provide indirect support for this prediction. Here, we conduct the first direct test of this prediction, using data from the well-studied system of clown anemonefish ( Amphiprion percula ) at Kimbe Island, in Papua New Guinea. Amphiprion percula live in small breeding groups that inhabit sea anemones. These groups can be thought of as populations within a metapopulation. We use the x- and y -coordinates of each anemone to determine the expected distribution of dispersal distances (the distribution of distances between each and every population in the metapopulation). We use parentage analyses to trace recruits back to parents and determine the observed distribution of dispersal distances. Then, we employ a logistic model to (i) compare the observed and expected dispersal distance distributions and (ii) determine the relationship between the probability of successful dispersal and the distance between populations. The observed and expected dispersal distance distributions are significantly different ( p < 0.0001). Remarkably, the probability of successful dispersal between populations decreases fivefold over 1 km. This study provides a framework for quantitative investigations of larval dispersal that can be applied to other species. Further, the approach facilitates testing biological and physical hypotheses for the factors influencing larval dispersal in unison, which will advance our understanding of marine population connectivity.

scholarly journals Animal movement drives variation in seed dispersal distance in a plant–animal network

2019 ◽  
Vol 286 (1894) ◽  
pp. 20182007 ◽  
Author(s):  
E. Rehm ◽  
E. Fricke ◽  
J. Bender ◽  
J. Savidge ◽  
H. Rogers
Keyword(s):  
Seed Dispersal ◽  
Animal Movement ◽  
Bird Species ◽  
Dispersal Distance ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Gut Passage ◽  
Dispersal Distances ◽  
Seed Dispersal Distance ◽  
Passage Times

Frugivores play differing roles in shaping dispersal patterns yet seed dispersal distance is rarely quantified across entire communities. We model seed dispersal distance using gut passage times and bird movement for the majority (39 interactions) of known bird–tree interactions on the island of Saipan to highlight differences in seed dispersal distances provided by the five avian frugivores. One bird species was found to be a seed predator rather than a disperser. The remaining four avian species dispersed seeds but differences in seed dispersal distance were largely driven by interspecific variation in bird movement rather than intraspecific variation in gut passage times. The median dispersal distance was at least 56 m for all species-specific combinations, indicating all species play a role in reducing high seed mortality under the parent tree. However, one species—the Micronesian Starling—performed 94% of dispersal events greater than 500 m, suggesting this species could be a key driver of long-distance dispersal services (e.g. linking populations, colonizing new areas). Assessing variation in dispersal patterns across this network highlights key sources of variation in seed dispersal distances and suggests which empirical approaches are sufficient for modelling how seed dispersal mutualisms affect populations and communities.

scholarly journals The good, the bad and the ugly of marine reserves for fishery yields

2015 ◽  
Vol 370 (1681) ◽  
pp. 20140276 ◽  
Author(s):  
Giulio A. De Leo ◽  
Fiorenza Micheli
Keyword(s):  
Stochastic Model ◽  
Larval Dispersal ◽  
Environmental Variability ◽  
Marine Reserves ◽  
Maximum Sustainable Yield ◽  
Social Benefits ◽  
Spatially Explicit ◽  
Sustainable Yield ◽  
Population Abundance ◽  
Quota Management

Marine reserves (MRs) are used worldwide as a means of conserving biodiversity and protecting depleted populations. Despite major investments in MRs, their environmental and social benefits have proven difficult to demonstrate and are still debated. Clear expectations of the possible outcomes of MR establishment are needed to guide and strengthen empirical assessments. Previous models show that reserve establishment in overcapitalized, quota-based fisheries can reduce both catch and population abundance, thereby negating fisheries and even conservation benefits. By using a stage-structured, spatially explicit stochastic model, we show that catches under quota-based fisheries that include a network of MRs can exceed maximum sustainable yield (MSY) under conventional quota management if reserves provide protection to old, large spawners that disproportionally contribute to recruitment outside the reserves. Modelling results predict that the net fishery benefit of MRs is lost when gains in fecundity of old, large individuals are small, is highest in the case of sedentary adults with high larval dispersal, and decreases with adult mobility. We also show that environmental variability may mask fishery benefits of reserve implementation and that MRs may buffer against collapse when sustainable catch quotas are exceeded owing to stock overestimation or systematic overfishing.

scholarly journals Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information

2009 ◽  
Vol 67 (2) ◽  
pp. 258-269 ◽  
Author(s):  
Ernesto Jardim ◽  
Santiago Cerviño ◽  
Manuela Azevedo
Keyword(s):  
Management Strategies ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Merluccius Merluccius ◽  
Total Allowable Catch ◽  
Recovery Plan ◽  
Stock Biomass ◽  
Spawning Stock ◽  
The Impact

Abstract Jardim, E., Cerviño, S., and Azevedo, M. 2010. Evaluating management strategies to implement the recovery plan for Iberian hake (Merluccius merluccius); the impact of censored catch information. – ICES Journal of Marine Science, 67: 258–269. Iberian hake assessment revealed an increase in fishing mortality (F) despite enforcement of a recovery plan. Recent landings exceeded the total allowable catch and discarding rates were high. Alternative management strategies based on F control were evaluated with respect to the probability of recovering spawning-stock biomass (SSB), expected profits, and robustness to uncertainty on catch information and stock dynamics. Results showed that the use of censored catch data, i.e. excluding the Gulf of Cádiz or discards, may lead to inappropriate conclusions. Reducing fishing mortality was necessary for SSB to recover. An Fmax strategy with discard reduction showed the highest probability of rebuilding SSB and led the fishery to sustainable exploitation, with an expected %SPR of 30–40% in 2025, mean individual weight in the landings of 450 g in 2015, and yield increasing by >20%. Because of uncertainty in the estimates of maximum sustainable yield, management strategies based on FMSY were least robust, but all strategies were robust to alternative stock–recruit models.

scholarly journals Study of Maximum Sustainable Yield of Rabbitfish (Siganus sp.) in Makassar Waters

2020 ◽  
pp. 98-107
Author(s):  
Moh. Tauhid Umar ◽  
Sharifuddin Bin Andy Omar ◽  
Suwarni Suwarni
Keyword(s):  
Time Series Data ◽  
Production Method ◽  
Maximum Sustainable Yield ◽  
Series Data ◽  
Annual Data ◽  
Sustainable Yield ◽  
Catch Per Unit Effort ◽  
Total Allowable Catch ◽  
Average Production ◽  
Fisheries Statistics

This study aims to estimate the potential of fish resources which include catch per unit effort (CPUE), Maximum Sustainable Yield (MSY), optimum efforts, exploitation rates and total allowable catch (TAC) of Rabbitfish in Makassar waters. This study uses time-series data, namely annual data from the fisheries statistics report at the Office of Marine and Fisheries Service, South Sulawesi Province from 2007 until. 2016. The method used to predict fish resource potential in the study is the Surplus Production method referring to the Schaefer model. The results of the study showed that the average production and standard efforts in the 10-year period were 78.8 tons per year and 1304 standard units per year respectively. The estimation results obtained by MSY and the optimum efforts of rabbitfish per year were 104 tons and 1142 standard units, respectively and total allowable catches (TAC) are 82.979 tons per year. The level of utilization of rabbitfish resources in Makassar waters in the last three years has been overexploitation.

Food and Empire

2012 ◽  
Author(s):  
Jayeeta Sharma
Keyword(s):  
Food Consumption ◽  
American Empire ◽  
Long Distance ◽  
The Past ◽  
Production And Distribution ◽  
Elite Status ◽  
The Impact ◽  
Global Food ◽  
Modern Technologies

Between 1926 and 1933, the Empire Marketing Board used a myriad of advertisements, posters, exhibits, and films to promote the empire's food products to British homes. The publicity campaigns were intended to show that tea from India or fruit from Australia was not foreign, but also British. Whether the Board was successful in its bid to promote intra-imperial food consumption, indeed, whether those efforts were needed in the first place, was not clear. This article focuses on foods from Asia and America that were originally thought to be exotic in Europe, initially served as indicators of elite status, and their gradual dissemination downwards. It also examines the role of long-distance trade and modern technologies in the production and distribution of new agro-industrial foods across networks of imperial knowledge and commodity circulation. The article concludes by assessing the impact of global food corporations' domination in the contemporary era, which in many ways can be seen as the equivalent of the European and American empire of the past.

scholarly journals The impact of long-range dispersal on gene surfing

2020 ◽  
Vol 117 (14) ◽  
pp. 7584-7593 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek
Keyword(s):  
Genetic Variation ◽  
Long Range ◽  
Range Expansion ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Coarse Grained ◽  
Coarse Grained Model ◽  
Species Invasions ◽  
Dispersal Distances ◽  
The Impact

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: Depending on the tail of the dispersal distance distribution, diversity can be either preserved (i.e., many variants survive) or lost (i.e., one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.

scholarly journals From sectors to speckles: The impact of long-range migration on gene surfing

2019 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek
Keyword(s):  
Genetic Variation ◽  
Long Range ◽  
Range Expansion ◽  
Spatial Genetic Structure ◽  
Dispersal Distance ◽  
Coarse Grained ◽  
Coarse Grained Model ◽  
Species Invasions ◽  
Dispersal Distances ◽  
The Impact

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well-studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: depending on the tail of the dispersal distance distribution, diversity can either be preserved (i.e. many variants survive) or lost (i.e. one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.

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