Ray Hilborn

University of Washington Seattle | UW · School of Aquatic and Fishery Sciences

Spillover is a term commonly applied to the dispersal of fish and/or larvae from inside a closed area to areas open to fishing. The presence of spillover is often quantified by measuring gradients in attributes such as abundance or catch rates near the boundaries of closed areas or by measuring higher abundance inside closed areas compared to outsi...

Spillover is a term commonly applied to the movement of fish from inside a closed area to areas open to fishing outside of the closure and is usually identified by gradients in abundance or catch rates near the boundaries. It is commonly assumed that such gradients indicate that the closed area has benefitted the fishery and the total abundance of...

Although most fisheries assessment and management focuses on the status of individual stocks, and regulations are commonly established as single-species total allowable catch limits (TACs), much of the catch from global fisheries comes from mixed-stock fisheries where species cannot be harvested separately. We show that in some fisheries where TAC...

Drifting fish aggregating devices (dFADs) are human‐made floating objects widely used by tropical tuna purse seine (PS) fisheries to increase catch of target species. However, dFAD use has several negative impacts, including increased potential for overfishing, higher juvenile tuna catch, higher bycatch compared to other PS fishing modes, ghost‐fis...

Mobile bottom contact gear such as trawls is widely considered to have the highest environmental impact of commonly used fishing gears, with concern about impact on benthic communities, bycatch, and carbon footprint frequently highlighted as much higher than other forms of fishing. As a result, the use of such gears has been banned or severely rest...

The status of federally managed fisheries in the United States is well monitored, but the condition of other marine fisheries, whether state‐managed, territory‐managed or unmanaged, is less understood and often unknown. We used expert surveys to characterize the management systems of non‐federally managed fisheries in US coastal marine states and o...

We present a novel adaptation of the classic discrete delay‐difference model, a continuous delay‐differential model (cDDM), which can adequately represent population dynamics of stocks that turn over rapidly and continuously over time (e.g., small pelagic fish, small tunas, and shrimps). We used the Northern‐Central Peruvian anchoveta stock ( Engra...

Small pelagic fishes are used for human consumption, fishmeal and fish oil. They constitute 25% of global fish catch and have been of considerable conservation concern because of their intermediate position in aquatic food webs, often being a dominant dietary component of marine predators. This paper provides an overview of trends in abundance and...

Significance The incidental catch of threatened species is still one of the main barriers to fisheries sustainability. What would happen if we closed 30% of the ocean to fishing with the goal of reducing bycatch? Analyzing 15 different fisheries around the globe, we found that under static area management, such as classic no-take marine area closur...

Bottom trawling is widespread globally and impacts seabed habitats. However, risks from trawling remain unquantified at large scales in most regions. We address these issues by synthesizing evidence on the impacts of different trawl-gear types, seabed recovery rates, and spatial distributions of trawling intensity in a quantitative indicator of bio...

Understanding the status of fish stocks is a critical step in ensuring the ecological and economic sustainability of marine ecosystems. However, at least half of global catch and a vast majority of global fisheries lack formal stock assessments, largely due to a lack of sufficient data. Catch data, loosely referring to any catch records be it inclu...

The pelagic fisheries beyond the continental shelves are currently managed with a range of tools largely based on regulating effort or target catch. These tools comprise both static and dynamic area‐based approaches to include gear limitations, closed areas and bycatch limits. There are increasing calls for additional area‐based interventions, part...

Rebuilding overfished stocks is central to fisheries policy, with the United States Magnuson-Stevens Act aligning with the United Nations Sustainable Development Goal 14.4 “to restore fish stocks in the shortest time feasible at least to levels that can produce maximum sustainable yield.” In mixed stock fisheries, very low allowable catches for reb...

Implementation of the United Nations Sustainable Development Goals requires assessments of the global state of fish populations. While we have reliable estimates of stock status for fish populations accounting for approximately half of recent global catch, our knowledge of the state of the majority of the world's “unassessed” fish stocks remains hi...

Marine protected areas (MPAs) cover 3–7% of the world's ocean, and international organizations call for 30% coverage by 2030. Although numerous studies show that MPAs produce conservation benefits inside their borders, many MPAs are also justified on the grounds that they confer conservation benefits to the connected populations that span beyond th...

We review the status of groundfish stocks using published scientific assessments for 349 individual stocks constituting 90% of global groundfish catch. Overall, average stock abundance is increasing and is currently above the level that would produce maximum sustainable yield (MSY). Fishing pressure for cod‐like fishes (Gadiformes) and flatfishes (...

Which management actions work best to prevent or halt overfishing and to rebuild depleted populations? A comprehensive evaluation of multiple, co-occurring management actions on the sustainability status of marine populations has been lacking. Here, we compiled detailed management histories for 288 assessed fisheries from around the world (accounti...

Increasing recruitment per mature adult as density declines is a key factor in being able to sustainably exploit populations and the extent of this increase is closely related to the sustainable exploitation rate of fish stocks. Stock-recruitment estimates typically show surprisingly large increases in egg to recruitment survival as density decline...

Recreational fishing benefits associated with angling opportunity, such as fishing season duration and certainty of season duration, may outweigh trip-based benefits, such as retained catch, in measures of angler utility. We developed an age-structured population dynamics model to predict how these three beneficial attributes are affected by four r...

Fishing cooperatives around the world have increasingly taken on co-management of commercial fisheries in recent decades, with generally positive results in meeting management targets and increasing economic value. To better understand which commercial fisheries or fleets are likely to form cooperative associations in the future, we utilized a data...

FAO Fisheries and Aquaculture Technical Paper No. 665, FAO, Rome. 134 p.

Bottom trawl fishing is a controversial activity. It yields about a quarter of the world's wild seafood, but also has impacts on the marine environment. Recent advances have quantified and improved understanding of large‐scale impacts of trawling on the seabed. However, such information needs to be coupled with distributions of benthic invertebrate...

Trawl fishing constitutes an important part of the marine fisheries sector in Southeast Asia. It provides livelihoods and food for millions of people in coastal communities as well as feed for the region’s growing aquaculture sector. Trawl fisheries suffer from a multitude of problems, including overcapacity, excessive fishing effort, poor profitab...

Bottom trawl fisheries are the most widespread source of anthropogenic physical disturbance to seabed habitats. Development of fisheries‐, conservation‐ and ecosystem‐based management strategies requires the selection of indicators of the impact of bottom trawling on the state of benthic biota. Many indicators have been proposed, but no rigorous te...

Marine fish stocks are an important part of the world food system and are particularly important for many of the poorest people of the world. Most existing analyses suggest overfishing is increasing, and there is widespread concern that fish stocks are decreasing throughout most of the world. We assembled trends in abundance and harvest rate of sto...

Managers of recreational fisheries make assumptions about what anglers value, often emphasizing factors directly related to catch. Evaluations that include both catch and non-catch aspects of recreational fishing, as well as the trade-offs between attributes that are trip-based and those that measure opportunity over a season, are rarely be incorpo...

Bottom trawling accounts for almost one quarter of global fish landings but may also have significant and unwanted impacts on seabed habitats and biota. Management measures and voluntary industry actions can reduce these impacts, helping to meet sustainability objectives for fisheries, conservation and environmental management. These include change...

The population dynamics of forage fish are often ‘boom or bust’, and variation in recruitment may be a contributing factor to changes in abundance. Here we applied several methods for identifying stock recruit relationships (SRR) to 52 forage fish stocks: a time-invariant Ricker model and two time-varying methods (dynamic linear models and regime-b...

[This corrects the article DOI: 10.1371/journal.pone.0043765.].

[This corrects the article DOI: 10.1371/journal.pone.0056684.].

Funding received by RH during the 5 years prior to publication of this article. (XLSX)

Funding received by RH during the 5 years prior to publication of this article. (XLSX)

Bristol Bay, Alaska, is home to the largest sockeye salmon (Oncorhynchus nerka) fishery in the world, harvesting an average of 25 million fish with an ex-vessel value exceeding US$100 million annually. Daily fishing effort is adaptively managed to achieve stock-specific escapement goals. Traditional methods for defining these goals relied on stock–...

Commercial salmon harvests have declined dramatically for all Pacific salmon species in British Columbia, mainly over the period 1995–2000. Much of this decline is attributable to declining abundance, but some of it has been due to deliberate reduction in allowable exploitation rates. Various reasons have been given for this reduction, but the main...

Bottom trawling is the most widespread human activity directly affecting seabed habitats. Assessment and effective management of the effects of bottom trawling at the scale of fisheries requires an understanding of differences in sensitivity of biota to trawling. Responses to disturbance are expected to depend on the intrinsic rate of increase in p...

Significance We conducted a systematic, high-resolution analysis of bottom trawl fishing footprints for 24 regions on continental shelves and slopes of five continents and New Zealand. The proportion of seabed trawled varied >200-fold among regions (from 0.4 to 80.7% of area to a depth of 1,000 m). Within 18 regions, more than two-thirds of seabed...

Many analyses of fishery recovery have demonstrated the potential biological and economic benefits of management reform, but few have compared these to the associated costs of management upgrades, which can be substantial. This study aims to determine if the projected economic benefits of management reform outweigh the increases in management costs...

Total cost of management under various cost assumptions for the USA. Total cost of management for the USA under alternative calculation approaches. (TIFF)

Average percentages of total management costs attributed to administration, research, and enforcement services. Values in the second column represent the outcomes when using the most recent administration, research, and enforcement cost reported in each country, while values in the third column represent the outcomes when the mean value of cost in...

Benefit-cost ratio (BCR) results for top 25. Benefit-cost ratios (BCRs) for top 25 countries in terms of 2012 landing volume (MTs). (DOCX)

Benefit-cost ratios (BCRs) for countries in database. Benefit-cost ratios for the 30 countries in the management cost database. (DOCX)

Supplementary material and methods. Additional analyses and results. (PDF)

Survey responses. Survey responses from group of experts. (TIFF)

Example survey. Survey used to collect information regarding the relevant cost of management from the group of experts. (XLSX)

Breakdown of current assessments and approaches to management. This figure includes the 30 countries included in the management cost database for which there are future harvest and profit projections from the bioeconomic model. The “Other” category represents landings from fisheries managed under input controls and/or unregulated open access. (TIFF...

Management cost database. Administration, research, and enforcement costs used in this study. This file contains both the most recent cost values and the average cost values for each category in each country. (CSV)

This paper presents a novel approach for assessing sources selectivity in test fisheries using the Port Moller test fishery (PMTF) as a case study. The PMTF intercepts sockeye salmon (Oncorhynchus nerka) migrating to Bristol Bay, Alaska, to estimate run strength and timing. In 2011, the mesh size of gillnets used in the test fishery was decreased f...

We reviewed 148 assessments of animal source food (ASF) production for livestock, aquaculture, and capture fisheries that measured four metrics of environmental impact (energy use, greenhouse‐gas emissions, release of nutrients, and acidifying compounds) and standardized these per unit of protein production. We also examined additional literature o...

Life-cycle models combine several strengths for estimating population parameters and biological reference points of harvested species and are particularly useful for those exhibiting distinct habitat shifts and experiencing contrasting environments. Unfortunately, time series data are often limited to counts of adult abundance and harvest. By incor...

We develop an economically sophisticated management strategy evaluation for four sockeye salmon (Onchorhynchus nerka) fishing districts in Bristol Bay, Alaska, to evaluate whether proposed increases in escapement goals — the number of fish allowed up each river to spawn — could improve fishery outcomes for the industry and the region. Higher escape...

Bottom-contact fishing gears are globally the most widespread anthropogenic sources of direct disturbance to the seabed and associated biota. Managing these fishing disturbances requires quantification of gear impacts on biota and the rate of recovery following disturbance. We undertook a systematic review and meta-analysis of 122 experiments on th...

Knowledge about population responses to environmental variability, including extreme climatic events, is crucial for understanding their current status and likely fate under future environmental change. The frequency and intensity of extreme events is projected to increase, especially in freshwater ecosystems. Anadromous fishes depend on freshwater...

Ecosystem-based fisheries management (EBFM) was developed to move beyond single species management by incorporating ecosystem considerations for the sustainable utilization of marine resources. Due to the wide range of fishery characteristics, including different goals of fisheries management across regions and species, theoretical best practices f...

EBFM implementation scores. EBFM implementation scores for each fishery (rows) in various categories (columns). Score values of 0, 0.5, and 1 were used to denote whether a criterion was met (1 = black), partially met (0.5 = gray), or not met at all (0 = white). The final row and column are the average fishery and criterion scores. The rows are sort...

Criteria and references used to score each fishery. References and justifications used to score fisheries according to EBFM criteria listed in Table 1. (PDF)

Microevolutionary processes determine levels of local adaptation within populations and presumably affect population productivity, but selection and phenotypic evolution have not often been linked explicitly to population dynamics in the wild. Here, we describe a stochastic, individual-based model that simulates evolutionary and demographic effects...

Large pelagic fishes are assessed and managed by tuna Regional Fisheries Management Organizations (tRFMOs). These organizations have been criticized for not meeting conservation objectives, which may relate to aspects of governance and management. No previous studies have systematically evaluated why management performance differs among tRFMOs and...

Significance Recent years have witnessed strenuous ongoing debate about the sustainability of many commercial fisheries. Here we apply commonly accepted principles of fishery science to consider the impact of price flexibility on long-term fishery sustainability in an era of increasing demand due to population increase and rising economic expectati...

Aim Trawling is the most widespread direct human disturbance on the seabed. Knowledge of the extent and consequences of this disturbance is limited because large‐scale distributions of seabed fauna are not well known. We map faunal distributions in the Australian Exclusive Economic Zone ( EEZ ) and quantify the proportion of their abundance that oc...

Assessment of fisheries vulnerability to climate change is an important step for enhancing the understanding and decision-making to reduce such vulnerability. This study aimed to provide an analysis of country level vulnerability focusing on food security implications of climatic disturbances on marine fisheries. The comparative magnitude and distr...

Bottom trawling is the most widespread human activity affecting seabed habitats. Here, we collate all available data for experimental and comparative studies of trawling impacts on whole communities of seabed macroinvertebrates on sedimentary habitats and develop widely applicable methods to estimate depletion and recovery rates of biota after traw...

Many rockfish species are long-lived and thought to be susceptible to being overfished. Hypotheses about the importance of older female rockfish to population persistence have led to arguments that marine reserves are needed to ensure the sustainability of rockfish populations. However, the implications of these hypotheses for rockfish population d...

Citation: Gutierrez, N. L., P. Halmay, R. Hilborn, A. E. Punt, and S. Schroeter. 2017. Exploring benefits of spatial cooperative harvesting in a sea urchin fishery: an agent-based approach. Ecosphere 8(7): Abstract. Sedentary or low-mobility organisms show a high degree of dependency with their sub-strate, where its heterogeneity often determines s...

Understanding population-specific spawner–recruit relationships is necessary for sustainable salmon management. Where multiple populations are harvested together, run reconstruction methods partition mixed-stock catches and allocate recruits back to their populations of origin. Traditional run reconstruction methods often use age composition data t...

The oceans provide food, employment and income for billions of people. We analyzed data from scientific stock assessments, and from a statistical model for other fish stocks, to summarize the past and present status, and the potential catch, abundance and profit for 4713 fish stocks constituting 78% of global fisheries. Three major scenarios of fut...

This paper explores the impact of fishing low trophic level “forage” species on higher trophic level marine predators including other fish, birds and marine mammals. We show that existing analyses using trophic models have generally ignored a number of important factors including (1) the high level of natural variability of forage fish, (2) the wea...

Abrupt shifts in natural resources and their markets are a ubiquitous challenge to human communities. Building resilient social-ecological systems requires approaches that are robust to uncertainty and to regime shifts. Harvesting diverse portfolios of natural resources and adapting portfolios in response to change could stabilize economies reliant...

Supplementary Figures and Supplementary Tables