Sean C Anderson

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

Sustainability indices are proliferating, both to help synthesize scientific understanding and inform policy. However, it remains poorly understood how such indices are affected by underlying assumptions of the data and modelling approaches used to compute indicator values. Here, we focus on one such indicator, the fisheries goal within the Ocean H...

Many of the world's fisheries are unassessed, with little information about population status or risk of overfishing. Unassessed fisheries are particularly predominant in developing countries and in small‐scale fisheries, where they are important for food security. Several catch‐only methods based on time series of fishery catch and commonly availa...

We thank Youngflesh and Lynch (1) for their thoughtful comments on our paper (2). As they note, we should have mentioned immigration and emigration alongside the intrinsic population properties (e.g., population birth rate, mortality, and age at maturity) and extrinsic causes of black-swan events (e.g., extreme climate, disease, predation, competit...

Significance Black swans—statistically improbable events with profound consequences—happen more often than expected in financial, social, and natural systems. Our work demonstrates the rare but systematic presence of black-swan events in animal populations around the world (mostly birds, mammals, and insects). These events are predominantly downwar...

The exploitation status of marine fisheries stocks worldwide is of critical importance for food security, ecosystem conservation, and fishery sustainability. Applying a suite of data-limited methods to global catch data, combined through an ensemble modeling approach, we provide quantitative estimates of exploitation status for 785 fish stocks. Fif...

Fishery managers must often reconcile conflicting estimates of population status and trend. Superensemble models, commonly used in climate and weather forecasting, may provide an effective solution. This approach uses predictions from multiple models as covariates in an additional “superensemble” model fitted to known data. We evaluated the potenti...

Theory predicts that bottom-heavy biomass pyramids or 'stacks' should predominate in real-world communities if trophic-level increases with body size (mean predator-to-prey mass ratio (PPMR) more than 1). However, recent research suggests that inverted biomass pyramids (IBPs) characterize relatively pristine reef fish communities. Here, we estimate...

Human-wildlife conflicts impose considerable costs to people and wildlife worldwide. Most research focuses on proximate causes, offering limited generalizable understanding of ultimate drivers. We tested three competing hypotheses (problem individuals, regional population saturation, limited food supply) that relate to underlying processes of human...

Perhaps the most pressing issue in predicting biotic responses to present and future global change is understanding how environmental factors shape the relationship between ecological traits and extinction risk. The fossil record provides millions of years of insight into how extinction selectivity (i.e., differential extinction risk) is shaped by...

Marine taxa are threatened by anthropogenic impacts, but knowledge of their extinction vulnerabilities is limited. The fossil record provides rich information on past extinctions that can help predict biotic responses. We show that over 23 million years, taxonomic membership and geographic range size consistently explain a large proportion of extin...

Climate change is likely to lead to increasing population variability and extinction risk. Theoretically, greater population diversity should buffer against rising climate variability, and this theory is often invoked as a reason for greater conservation. However, this has rarely been quantified. Here we show how a portfolio approach to managing po...

Retrospective patterns are systematic changes in estimates of population size, or other assessment model-derived quantities, that occur as additional years of data are added to, or removed from, a stock assessment. These patterns are an insidious problem, and can lead to severe errors when providing management advice. Here, we use a simulation fram...

Exploited marine populations are thought to be regulated by the effects of fishing, species interactions and climate. Yet, it is unclear how these forces interact and vary across a species’ range. We conducted a meta‐analysis of American lobster ( H omarus americanus ) abundance data throughout the entirety of the species’ range, testing competing...

Data S1. WinBUGS and R code for building occupancy models and GAMMs, respectively, plus functions to generate testing datasets.

Long-term wildlife monitoring involves collecting time series data, often using the same observers over multiple years. Aging-related changes to these observers may be an important, under-recognized source of error that can bias management decisions. In this study, we used data from two large, independent bird surveys, the Atlas of the Breeding Bir...

Simulation testing is an important approach to evaluating fishery stock assessment methods. In the last decade, the fisheries stock assessment modeling framework Stock Synthesis (SS3) has become widely used around the world. However, there lacks a generalized and scriptable framework for SS3 simulation testing. Here, we introduce ss3sim, an R packa...

Anthropogenic climate change will present both opportunities and challenges for pool-breeding amphibians. Increased water temperature and accelerated drying may directly affect larval growth, development, and survival, yet the combined effects of these processes on larvae with future climate change remain poorly understood. Increased surface temper...

A typical assumption used in most fishery stock assessments is that natural mortality (M) is constant across time and age. However, M is rarely constant in reality as a result of the combined impacts of exploitation history, predation, environmental factors, and physiological trade-offs. Misspecification or poor estimation of M can lead to bias in...

Management of marine resources depends on the assessment of stock status in relation to established reference points. However, many factors contribute to uncertainty in stock assessment outcomes, including data type and availability, life history, and exploitation history. A simulation–estimation framework was used to examine the level of bias and...

Scientific management of wildlife requires confronting the complexities of natural and social systems. Uncertainty poses a central problem. Whereas the importance of considering uncertainty has been widely discussed, studies of the effects of unaddressed uncertainty on real management systems have been rare. We examined the effects of outcome uncer...

A financial portfolio metaphor is often used to describe how population diversity can increase temporal stability of a group of populations. The portfolio effect (PE) refers to the stabilizing effect from a population acting as a group or ‘portfolio’ of diverse subpopulations instead of a single homogeneous population or ‘asset’. A widely used meas...

Conservation successes can and do happen, however, the process by which society achieves them remains unclear. Using a novel culturomics approach, we analyse word usage within digitized texts to assess the chronological order in which scientists, the public, and policymakers engage in the conservation process for three prominent conservation issues...

In the coming century, life in the ocean will be confronted with a suite of environmental conditions that have no analog in human history. Thus, there is an urgent need to determine which marine species will adapt and which will go extinct. Here, we review the growing literature on marine extinctions and extinction risk in the fossil, historical, a...

Anderson, S. C., Branch, T. A., Ricard, D., and Lotze, H. K. 2012. Assessing global marine fishery status with a revised dynamic catch-based method and stock-assessment reference points. – ICES Journal of Marine Science, 69: . The assessment of fishery status is essential for management, yet fishery-independent estimates of abundance are lacking fo...

In recent decades, invertebrate fisheries have expanded in catch and value worldwide. One increasingly harvested group is sea cucumbers (class Holothuroidea), which are highly valued in Asia and sold as trepang or bêche-de-mer. We compiled global landings, economic data, and country-specific assessment and management reports to synthesize global tr...

Species status assessments are often hindered by a paucity of demographic, abundance, or distributional data. Although extinction-risk correlates have been identified, their wide applicability may be compromised by differences in the variables examined, modeling technique, and phylogenetic or distributional scale. Here, we apply a common analytical...

In much of the northwest Atlantic Ocean, commercially important snow crab Chionoecetes opilio stocks have increased in abundance since the decline and collapse of major groundfish stocks such as Atlantic cod Gadus morhua. We examined 3 hypotheses to explain variation in the abundance of snow crabs across 10 regions: (1) climate control of both spec...

Mean annual invertebrate catch by taxonomic group in each Large Marine Ecosystem (LME) from 2000–2004. (1.13 MB TIF)

Effects of taxonomic precision in reporting on predicted trends in diversity of invertebrates fished. (A) Increasing reporting of invertebrate taxa fished divided into species level (blue), larger grouping level (green), and combined (red). Dark lines represent mean and shaded region represents standard error assuming a negative binomial distributi...

Supplementary description of the methods. (0.15 MB PDF)

Percentage of all countries reporting catch of various invertebrate taxonomic and species groups. Dark lines represent smooth estimates obtained from a loess smoother (smoothing span 50% of the data). Light lines represent unfiltered data. (0.28 MB TIF)

An example of time to peak catch vs. year of fishery initiation by taxonomic grouping for one random sampling of censored fisheries (red dots). Black dots represent known data points. In our analysis, the red dots were resampled 1000 times from possible time to peak values. Blue dots represent fisheries for which there were no fisheries to sample f...

Distance and starting year of sea cucumber fisheries by country. Listed are each country's largest city (by population), its location, its distance from Hong Kong, the starting year of the sea cucumber fishery, and a verification reference. (0.09 MB PDF)

Major gear groupings of gear categories from the Sea Around Us Project catch database. (0.03 MB PDF)

Classification of invertebrate taxonomic groups into primary and secondary functional groups. Taxa are ordered approximately by decreasing trophic level. (0.05 MB PDF)

An example invertebrate catch series arranged by country for one invertebrate taxa: bivalves. Red lines indicate loess smoothed fits. Plots are ordered by cumulative catch since 1950. Vertical grey bars in title bars indicate log transformed cumulative catch, with bars near the right indicating the greatest cumulative catch and bars near the left i...

Illustration of our algorithm for dynamically assigning fishery status. Dots represent raw catch values, grey lines represent 3 of the loess functions fit to the data. Loess functions were built dynamically for each year but for clarity we show only the 3 functions which resulted in a change in status. By default a fishery was categorized as “expan...

Percentage of fisheries for species from various functional groups that were categorized into the 4 fishery status categories. See section Assessment of fishery status from catch trends and Fig. 4C for a description of the how the species were assigned to the functional groups. (0.18 MB TIF)

Characteristics of actual and simulated catch series. Frequency of log of mean catch values by fishery and log of the standard deviation of the residuals after fitting a loess smoother to each series (span = 0.5) from global invertebrate fisheries (A, B; grey background shading), and simulated series with σ = 0.1 (C, D), σ = 0.25 (E, F), and σ = 0....

Demonstration of our fishery status assessment algorithm to simulated data. (A–C) Example of simulated increasing and then stationary catch series with multiplicative log-normal error about a random mean: log standard deviation of error of 0.10 (A), 0.25 (B), and 0.50 (C). Black lines indicate unfiltered catch. Red lines indicate loess smoothed fit...

Methods used to determine years of initial peaks in catch. (A) Illustration of our algorithm for assigning year of initial peak catch. Dots represent raw catch values, grey line represents loess function fit through the entire catch series, and red line indicates loess function fit through data up to the year of initial peak catch. A fishery was co...

Worldwide, finfish fisheries are receiving increasing assessment and regulation, slowly leading to more sustainable exploitation and rebuilding. In their wake, invertebrate fisheries are rapidly expanding with little scientific scrutiny despite increasing socio-economic importance. We provide the first global evaluation of the trends, drivers, and...

Over the last two decades, low-trophic-level fisheries have rapidly expanded in Atlantic Canada, largely compensating for collapsed groundfisheries; however, concerns have been raised regarding the limited background knowledge for many newly targeted species and their overexploitation in other regions. Using government stock assessments, we evaluat...