Trevor A. Branch

University of Washington Seattle | UW

Animal behavior is motivated by the fundamental need to feed and reproduce, and these behaviors can be inferred from spatiotemporal variations in biological signals such as vocalizations. Yet, linking foraging and reproductive effort to environmental drivers can be challenging for wide‐ranging predator species. Blue whales are acoustically active m...

Shifts in spawning phenology may impact the early life stages of small pelagic fishes, affecting their first-year survival and recruitment. In Prince William Sound, Pacific herring is a key forage species that once supported commercial and subsistence fisheries for many decades, but collapsed in 1993 and has yet to recover. Starting in 1980, spawn...

The Southeast Pacific (SEP) or Chilean blue whale population is largely distributed between Northern Chilean Patagonia and the Eastern Tropical Pacific. Off South Georgia (SG), the majority of blue whales caught were Antarctic blue whales, but recent genetic and acoustic records indicate the possible presence of SEP individuals. To assess the prese...

When estimating mortality from disease with fish population models, common disease surveillance data such as infection prevalence are not always informative, especially for fast-acting diseases that may go unobserved in infrequently sampled populations. In these cases, seroprevalence — the proportion of fish with measurable antibody levels in their...

Incorporating ecological covariates into fishery stock assessments may improve estimates, but most covariates are estimated with error. Model selection criteria are often used to identify support for covariates, have some limitations and rely on assumptions that are often violated. For a more rigorous evaluation of ecological covariates, we used fo...

Extinction rates are increasing globally, and direct exploitation is an important driver. Many pathways have been proposed to explain how exploitation can lead to extinction. One of these proposed but understudied multispecies pathways is opportunistic exploitation, which occurs when a highly valuable but rare species is encountered and targeted du...

The goal of this project is to use acoustic signatures to detect, classify, and count the calls of four acoustic populations of blue whales so that, ultimately, the conservation status of each population can be better assessed. We used manual annotations from 350 h of audio recordings from the underwater hydrophones in the Indian Ocean to build a d...

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...

The United States seafood industry is undergoing rapid change, as a result of the current trade war with China, ongoing global COVID-19 pandemic, and new governance mandates. The Executive Order on Promoting American Seafood Competitiveness and Economic Growth , signed in May 2020, proposes wild-capture fisheries deregulation and prioritization of...

The US seafood sector is susceptible to shocks, both because of the seasonal nature of many of its domestic fisheries and its global position as a top importer and exporter of seafood. However, many data sets that could inform science and policy during an emerging event do not exist or are only released months or years later. Here, we synthesize mu...

Deviations from equal sex ratios in mammals can reveal insights into sex‐specific growth, survival, movements, and behavior. We assessed blue whale (Balaenoptera musculus) sex ratios based on 21,542 fetal and 311,901 whaling records, finding that males were slightly but significantly more common than females (51.3% fetal, 52.1% postnatal). Antarcti...

The United States seafood industry is undergoing rapid change, as a result of the current trade war with China, ongoing global COVID-19 pandemic, and new governance mandates. The new Executive Order (EO) on Promoting American Seafood Competitiveness and Economic Growth, signed in May 2020, proposes wild-capture fisheries deregulation and prioritiza...

In response to the COVID-19 pandemic, common government actions have been geared towards increasing social distancing, which has had consequent effects on businesses and livelihoods. In the US, the seafood sector has been hit hard by responses to COVID-19. Under normal conditions, most seafood expenditure is in restaurants, which influences seafood...

Pacific and Atlantic herring populations (genus Clupea) commonly experience episodic collapse and recovery. Recovery time durations are of great importance for the sustainability of fisheries and ecosystems. We collated information from 64 herring populations to characterize herring fluctuations and determine the time scales at low biomass and at h...

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...

Performance evaluation of data-limited, length-based methods is instrumental in determining and quantifying their accuracy under various scenarios and in providing guidance about model applicability and limitations. We conducted a simulation-estimation analysis to compare the performance of four length-based stock assessment methods: length-based T...

Bayesian inference is an appealing alternative to maximum likelihood estimation, but estimation can be prohibitively long for integrated fisheries stock assessments. Here, we investigated potential causes of long run times including high dimensionality, complex model structure, and inefficient Bayesian algorithms for four US assessments written in...

In the Southern Hemisphere, blue whales are currently divided into two subspecies, Antarctic blue whales (Balaenoptera musculus intermedia) and pygmy blue whales (B. m. brevicauda), but there is some debate about whether Chilean blue whales should also be considered as a separate subspecies. Here, we provide novel morphometric data to directly addr...

Catch share systems are generally expected to increase economic rents in fisheries by increasing harvest efficiency, reducing capital costs through consolidation, and increasing the value of landed catch. However, these benefits may have costs, as consolidation and the potential for associated change in spatial distribution in landings can hinder s...

The shifting baseline syndrome describes a gradual lowering of human cognitive baselines, as each generation accepts a lower standard of resource abundance or size as the new norm. There is strong empirical evidence of declining trends of abundance and body sizes of marine fish species reported from docks and markets. We asked whether these widespr...

Lists of search terms and online sources used to find articles on ‘newsworthy’ fish. Lists of search terms and online sources used to find articles on ‘newsworthy’ fish.

List of the 75 fish species reported in news items and assigned groupings. Species group categories include: all epipelagic shark species targeted recreationally and/or commercially (Oceanic sharks); epipelagic teleost fishes typically targeted by recreational fishers (Pelagic gamefish); or species not regularly targeted by fishers but notable for...

Quantile regression results. Results of quantile regression analyses for newsworthy fishes in our database. Quantile regressions highlighted in grey did not meet the minimum sample size ratio required (ratio > 5) and were therefore not shown in respective figures. Quantile regressions highlighted in bold met the minimum sample size threshold and we...

Relative weight of fish reported as being exceptionally large in printed news headlines from 1869 to 2015 for three categories of extinction risk. Weight of fish reported as being exceptionally large in printed news headlines from 1869 to 2015, relative to the maximum species-specific weight, for three categories of extinction risk: (A) unknown ris...

Age-structured fisheries model simulation. Methods for creating probability distributions of the relative length (Lhuge/Linf) caught in simulated age-structured populations with varying fishing mortalities (F = 0.05, F = 0.2, F = 0.8) for different sampling efforts (N = 10000 top row, N = 1000 middle row, N = 100 bottom row). Dotted black vertical...

Sensitivity to taxonomic uncertainty of trends in relative length of charismatic megafishes reported as being exceptional large in printed news headlines over time. Length of charismatic megafishes in printed news headlines from 1869 to 2015, relative to the maximum species-specific weight, (A) when all Mola are assumed to be Mola mola, and (B) whe...

Relative weight of pelagic gamefish, oceanic sharks, and charismatic megafish reported as being exceptionally large in printed news headlines. Weight of fish reported as being exceptionally large in printed news headlines from 1869 to 2015, relative to the maximum species-specific weight, for three species groups: (A) pelagic gamefish (n = 73), (B)...

Raw data used for analysis. The information gathered for each article retained in our analysis is given in the raw data. This includes article-specific data (e.g. species, reported measurements), species-specific data (e.g. proper and common names, length and weight data from FishBase and IGFA), and grouping information (species grouping, extinctio...

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

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

At the crux of the debate over the global sustainability of fisheries is what society must do to prevent over‐exploitation and aid recovery of fisheries that have historically been over‐exploited. The focus of debates has been on controlling fishing pressure, and assessments have not considered that stock production may be affected by changes in fi...

Hook-and-line surveys can be used to estimate population trends in fish species where conventional methods such as trawl, acoustic, visual, or pot surveys cannot be applied. Hook-and-line surveys allow for the collection of biological information, but the resultant indices of abundance may be biased. We designed simulations to address concerns arou...

Marine ecosystems have been heavily impacted by fishing pressure, which can cause major changes in the structure of communities. Fishing directly removes biomass and causes secondary effects such as changing predatory and competitive interactions and altering energy pathways, all of which affect the functional groups and size distributions of marin...

At the crux of the debate over the global sustainability of fisheries is what society must do prevent overexploitation of fisheries and aid recovery of fisheries that have historically been overexploited. The focus of debates has been on controlling fishing pressure and assessments have not considered that stock production may be affected by change...

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...

Researchers have long recognized the importance of ecological differences at the species level in structuring natural communities yet until recently have often overlooked the influence of intraspecific trait variation, which can profoundly alter community dynamics [1]. Human extraction of living resources can reduce intraspecific trait variation by...

Despite evidence that mobile bottom fishing gear causes physical damage to habitat-forming organisms on the seafloor, likely indirectly affecting associated fishes, it is difficult to determine how conservation and management policies influence such effects because researchers do not typically systematically quantify the extent and intensity of gea...

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...

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 Pacific herring (Clupea pallasii) population in Prince William Sound, Alaska crashed in 1993 and has yet to recover, affecting food web dynamics in the Sound and impacting Alaskan communities. To help researchers design and implement the most effective monitoring, management, and recovery programs, a Bayesian assessment of Prince William Sound...

Bayesian model code and data files for Prince William Sound herring stock assessment. (ZIP)

Bayesian inference is a powerful tool to better understand ecological processes across varied subfields in ecology, and is often implemented in generic and flexible software packages such as the widely used BUGS family (BUGS, WinBUGS, OpenBUGS and JAGS). However, some models have prohibitively long run times when implemented in BUGS. A relatively n...

Catches are commonly misreported in many fisheries worldwide, resulting in inaccurate data that hinder our ability to assess population status and manage fisheries sustainably. Under-reported catch is generally perceived to lead to overfishing, and hence, catch reconstructions are increasingly used to account for sectors that may be unreliably repo...

An overview is provided of catches, sighting surveys, acoustic detections, satellite tagging and abundance estimates for blue whales in the North Pacific. There are at least two populations: the eastern North Pacific population from the Gulf of Alaska to Mexico, and the western North Pacific population that extends from Japan through to the Gulf of...

Catch shares, where annual catch limits are divided among individuals, communities or cooperatives, are a commonly used fisheries management strategy to increase profits and reduce overcapitalization. Usually these quota shares can be sold or leased, which is theorized to allow for greater utilization of fleet-wide quota. However, this catch-quota...

We identify the 199 most-cited fisheries references up to July 2014, topped by Nelson's Fishes of the World. Few book chapters, databases or reports were included, but review articles and field guides were over-represented. Publishing in Science, Nature or Proceedings of the National Academy of Sciences USA is associated with a 34-fold increase in...

Commercial tunas and billfishes (swordfish, marlins and sailfish) provide considerable catches and income in both developed and developing countries. These stocks vary in status from lightly exploited to rebuilding to severely depleted. Previous studies suggested that this variability could result from differences in life-history characteristics an...

Significance What would extensive fishery reform look like? In addition, what would be the benefits and trade-offs of implementing alternative approaches to fisheries management on a worldwide scale? To find out, we assembled the largest-of-its-kind database and coupled it to state-of-the-art bioeconomic models for more than 4,500 fisheries around...

Individual quota (IQ) management systems in commercial marine fisheries are highly diverse, differing in the security, durability and exclusivity of the harvesting privilege and the transferability of quota units. This diversity in the degree of harvest rights may influence the effectiveness of IQ fisheries to meet management objectives. We conduct...

Whale watching has become increasingly popular as an ecotourism activity around the globe and is beneficial for environmental education and local economies. Southern Resident killer whales (Orcinus orca) comprise an endangered population that is frequently observed by a large whale watching fleet in the inland waters of Washington state and British...

Analysis of qualitative characteristics as factors. The qualitative vessel characteristics: type, orientation and propulsion system, were also analyzed as factors in the negative log likelihood model. (PDF)

Noise levels and average vessel length. There was no significant relationship between received noise levels (dB re 1 μPa) and average vessel length (m) per interval. Variation in average vessel length was skewed toward the smaller vessels. (TIF)

Noise levels and average vessel type. There was no significant relationship between received noise levels (dB re 1 μPa) and the average vessel type per interval. Variation in average vessel type was heavily skewed toward inflatables and no intervals where vessels were on average of the medium or large hard bottom distinction. (TIF)

Average distance of vessels to tagged whales and average vessel type. The average distance (m) of vessels to tagged whales had a highly significant correlation with average vessel type per interval (F1, 55 = 27.77, p<0.001). (TIF)

Noise levels and average vessel orientation. There was no significant relationship between received noise levels (dB re 1 μPa) and the average vessel orientation per interval. Orientation descriptions are relating the motor’s relationship to the whale (i.e. motor away indicates the motor is facing away from the whale, see Table 1). There was little...

Noise levels and average distance of vessels to tagged whales. There was no significant relationship between received noise levels (dB re 1 μPa) and the average distance of vessels to tagged whales (m) per interval. Variation in average vessel distance was slightly skewed toward closer distances. (TIF)

Average distance of vessels to tagged whales and average vessel length. The average distance (m) of vessels to tagged whales had a highly significant correlation with average vessel length (m) per interval (F1, 55 = 30.62, p<0.001). (TIF)

Average vessel length and average vessel type. The average vessel length (m) had a highly significant correlation with average vessel type per interval (F1, 55 = 67.47, p<0.001). (TIF)

Underlying data for analyses. Spreadsheet includes: whale and vessel locations, vessel characteristics, and received noise levels for all intervals in this study. (XLSX)

Noise levels and average propulsion system. There was no significant relationship between received noise levels (dB re 1 μPa) and the average vessel propulsion system per interval. Variation in average vessel propulsion system was very poor with outboard motors present on most vessels per interval. (TIF)

Average number of propellers and average vessel speed. The average number of propellers had a marginally significant correlation with average vessel speed per interval (F1, 55 = 3.385, p = 0.071). (TIF)

AICc results of models with qualitative characteristics as factors. Negative log likelihood model results when vessel type, propulsion system and orientation were included as factors. The AICc value for the full model excluding research vessel-only intervals where each qualitative characteristic was assigned a numerical value (according to Table 1)...

‘Fishermen’ and the gender-neutral ‘fishers’ are the most common terms used to describe people who fish in the English language. However, there is a considerable debate as to which term is most appropriate. In academic journals, usage of ‘fishers’ for people who fish began in the 1960s and increased over time, until in 2013 and 2014 ‘fishers’ first...

Length–weight relationships (LWRs) were developed for 85 reef and bottom-fish species from Guam. These are the first published LWRs for Guam, and include new LWRs for nine species lacking these relationships in FishBase.

There is considerable international concern and scientific debate about the current state and future of tuna stocks worldwide and the capacity of Regional Fisheries Management Organisations to manage the associated fisheries effectively. In some cases, this concern has extended to predictions of imminent collapse with minimal chances of recovery, e...

A handful of sensitivity analyses are presented for the assessment model of eastern North Pacific blue whales. We explore a likelihood profile for r, the impact of a uniform prior on lnK instead of K, an alternative set of abundance estimates, underreporting of catches, and the estimation of an additional variance parameter for the abundance estima...

Understanding demographic variation in recruitment and somatic growth is key to improving our understanding of population dynamics and forecasting ability. Although recruitment variability has been extensively studied, somatic growth variation has received less attention, in part because of difficulties in modeling growth from individual size-at-ag...

What are the greatest sizes that the largest marine megafauna obtain? This is a simple question with a difficult and complex answer. Many of the largest-sized species occur in the world’s oceans. For many of these, rarity, remoteness, and quite simply the logistics of measuring these giants has made obtaining accurate size measurements difficult. I...

Previous meta-analysis of spawner-recruit relationships suggested that depensatory behaviour is uncommon, and stocks pushed to low abundance are unlikely to suffer decreases in recruitment more severe than would be expected based on the decline in spawning stock. Using an updated database that has over 100 stocks that were depleted to less than 20%...

Blue whales were targeted in the North Pacific from 1905–1971 and are listed as endangered by the IUCN. Despite decades without whaling, abundance estimates for eastern North Pacific (ENP) blue whales (Balaenoptera musculus) suggest little evi-dence for a recent increase. One possible reason is fatal strikes by large ships, which have affected popu...