A5101520761- Marine and fisheries research
- Marine Bivalve and Aquaculture Studies
- Fish Ecology and Management Studies
- Coral and Marine Ecosystems Studies
- Genetic and phenotypic traits in livestock
- Coastal and Marine Management
- Data Analysis with R
Centre for Environment, Fisheries and Aquaculture Science
2013-2025
Lowestoft Hospital
2014
Suffolk University
2013
Abstract Management strategy evaluation ( MSE ) involves using simulation to compare the relative effectiveness for achieving management objectives of different combinations data collection schemes, methods analysis and subsequent processes leading actions. can be used identify a ‘best’ among set candidate strategies, or determine how well an existing performs. The ability facilitate fisheries its aims depends on uncertainty is represented, effectively results simulations are summarized...
Abstract The ability of management strategies to achieve the fishery goals are impacted by environmental variation and, therefore, also global climate change. Management can be modified use data using “dynamic B0” concept, and changing set years used define biomass reference points. Two approaches have been developed apply strategy evaluation evaluate impact on performance strategies. “mechanistic approach” estimates relationship between environment elements population dynamics fished...
Abstract Management strategy evaluation (MSE) is the state‐of‐the‐art approach for testing and comparing management strategies in a way that accounts multiple sources of uncertainty (e.g. monitoring, estimation, implementation). can help identify are robust to about life history target species its relationship other food web. Small pelagic fish anchovy, herring sardine) fulfil an important ecological role marine webs present challenges use MSE simulation‐based approaches. This due...
Abstract Most fisheries on commercially fished species are managed a stock‐by‐stock basis through catch limits. When set in isolation, limits ignore mixed‐fisheries interactions that result from catches by fishing fleets comprising multiple stocks, leading to quota imbalances with negative ecological and economic consequences. Tools needed efficiently account for their impact paving the way development of management approaches. Here, we introduce MixME, an R package simulation strategies...
We used fishery and survey data to calculate annual surplus production (ASP) instantaneous rates (ISPR) for eight anchovy nine sardine stocks. In addition, we calculated ASP per unit spawning area six Median was highest stocks with median biomass (mostly anchovies), typically about 16% of stock biomass. often negative, more frequently anchovies (36% years) than sardines (17% years). ISPR less variable autocorrelated longer-lived sardines). Strong increases tended be preceded by short, abrupt...
Abstract Despite high primary productivity, the yield of pelagic fish in southern Benguela is relatively low compared to that Humboldt system. Part constraint may be ability reproduce successfully a strongly pulsed upwelling environment, where enrichment, retention and concentration mechanisms are less compatible than Peru-Chile. Anchovy Engraulis capensis spawn upstream main centres on food-poor, thermally stratified western Agulhas Bank, over protracted summer season (October–February)...
Abstract de Moor, C. L., Butterworth, D. S., and De Oliveira, J. A. 2011. Is the management procedure approach equipped to handle short-lived pelagic species with their boom bust dynamics? The case of South African fishery for sardine anchovy. – ICES Journal Marine Science, 68: 2075–2085. Worldwide, small shoaling fish manifest rapid substantial natural changes in abundance. application a (MP), evaluated using simulation tests [i.e. MP otherwise known as strategy evaluation (MSE)], recommend...
We used fishery and survey data to calculate annual surplus production (ASP) instantaneous rates (ISPR) for eight anchovy nine sardine stocks. In addition, we calculated ASP per unit spawning area six Median was highest stocks with median biomass (mostly anchovies), typically about 16% of stock biomass. often negative, more frequently anchovies (36% years) than sardines (17% years). ISPR less variable autocorrelated longer-lived sardines). Strong increases tended be preceded by short, abrupt...
Abstract Butterworth, D. S., Bentley, N., De Oliveira, J. A. A., Donovan, G. P., Kell, L. T., Parma, M., Punt, E., Sainsbury, K. J., Smith, and Stokes, T. 2010. Purported flaws in management strategy evaluation: basic problems or misinterpretations? – ICES Journal of Marine Science, 67: 567–574. Rochet Rice, while recognizing evaluation (MSE) as an important step forward fisheries management, level a number criticisms at its implementation. Some their points are sound, such the need for care...
Pretty good yield (PGY) is a sustainable fish corresponding to obtaining no less than specified large percentage of the maximum (MSY). We investigated 19 European stocks test hypothesis that 95% PGY range inherently precautionary with respect impairing recruitment. An FMSY was calculated for each stock as fishing mortalities (F) lead an average catch at least MSY in long-term simulations. Further, reference point (FP.05) defined F resulting 5% probability spawning-stock biomass falling below...
We develop a spatially and seasonally explicit bioeconomic model with three fleet dynamics processes built in endogenously. The has been applied to the large French trawlers harvesting medium-depth demersal stock, North Sea saithe (i.e., pollock, Pollachius virens), mix of deepwater species over 10-year period (1999–2008), predictions have contrasted observations. best overall fit was achieved where effort allocation determined be 80% by traditions 20% economic opportunism harvest efficiency...
Abstract Maximum sustainable yield (MSY) is a well-established concept that mandated by legislation, and has clear theoretical meaning in terms of single stock. However, its definition problematic multispecies setting, which makes it more difficult to apply the MSY principle. In this study North Sea fish community, we consider several possible candidates, evaluate them their ability produce optimum long-term whilst avoiding unacceptable risk stock impairment. We perform evaluation with an...
Abstract Worldwide, the majorities of fish stocks are data-limited and lack fully quantitative stock assessments. Within ICES, such currently managed by setting total allowable catch without use target reference points. To ensure that advice is precautionary, we used management strategy evaluation to evaluate an empirical rule bases on recent catches, information from a biomass survey index, length frequencies, MSY point proxies. Twenty-nine were simulated covering wide range life histories....
The South African sardine Sardinops sagax resource is subjected to both directed fishing that targets adult fish, and bycatch of juvenile fish taken in the fisheries for anchovy Engraulis capensis round herring Etrumeus whiteheadi. Two separate TACs (Total Allowable Catch) are calculated management procedures considered. first a TAC linked abundance, second with an "anchovy" component coupled population dynamics as proportion TAC, plus "round herring" reflecting fixed tonnage independent...
Abstract Many data-limited fish stocks worldwide require management advice. Simple empirical procedures have been used to manage fisheries but do not necessarily ensure compliance with maximum sustainable yield objectives and precautionary principles. Genetic algorithms are efficient optimization for which the formalized as a fitness function. This can be included when testing in strategy evaluation. study explored application of genetic algorithm an catch rule found that this approach could...
Abstract Moderately data-limited fisheries can be managed with simple empirical management procedures without analytical stock assessments. Often, control rules adjust advised catches by the trend of an abundance index. We explored alternative approach where a relative harvest rate, defined catch to biomass index, is used and target level derived from analysing historical length data. This rate rule was tested generically strategy evaluation. A genetic algorithm deployed as optimisation...
This paper describes a methodology that combines meta-population theory and stock assessment models to gain insights about spatial heterogeneity of the in an operational time frame. The was tested with stochastic simulations for different degrees connectivity between sub-populations applied two case studies, North Sea cod (Gadus morua) Northeast Atlantic sardine (Sardina pilchardus). Considering biological components population can be partitioned into discrete units, we extended this idea...
Abstract Biased estimates of population status are a pervasive conservation problem. This problem has plagued assessments commercial exploitation marine species and can threaten the sustainability both populations fisheries. We develop computer‐intensive approach to minimize adverse effects persistent estimation bias in by optimizing operational harvest measures (harvest control rules) with closed‐loop simulation resource‐management feedback systems: management strategy evaluation. Using...
Abstract Fisheries management needs to ensure that resources are exploited sustainably, and the risk of depletion is at an acceptable level. However, often uncertainty about resource dynamics exists, data availability may differ substantially between fish stocks. This situation can be addressed through tiered systems, where tiers represent different limitations, tier‐specific stock assessment methods defined, aiming for equivalence across tiers. As case studies, we selected stocks European...
Abstract Many management bodies require applying the precautionary approach when managing marine fisheries resources to achieve sustainability and avoid exceeding limits. For data-limited stocks, however, defining achieving objectives can be difficult. Management procedures optimized towards specific with genetic algorithms. We explored feasibility of including an objective that limited risk a stock falling below various limit reference points in optimization routine for empirical control...