Predicting life history parameters for all fishes worldwide

Global patterns and drivers of fish reproductive potential on coral reefs

Fish fecundity scales hyperallometrically with body mass, meaning larger females produce disproportionately more eggs than smaller ones. We explore this relationship beyond the species-level to estimate the "reproductive potential" of 1633 coral reef sites distributed globally. We find that, at the site-level, reproductive potential scales hyperallometrically with assemblage biomass, but with a smaller median exponent than at the species-level. Across all families, modelled reproductive potential is greater in fully protected sites versus fished sites. This difference is most pronounced for the important fisheries family, Serranidae. When comparing a scenario where 30% of sites are randomly fully protected to a current protection scenario, we estimate an increase in the reproductive potential of all families, and particularly for Serranidae. Such results point to the possible ecological benefits of the 30 × 30 global conservation target and showcase management options to promote the sustainability of population replenishment.

Quantifying energy and nutrient fluxes in coral reef food webs

The movement of energy and nutrients through ecological communities represents the biological 'pulse' underpinning ecosystem functioning and services. However, energy and nutrient fluxes are inherently difficult to observe, particularly in high-diversity systems such as coral reefs. We review advances in the quantification of fluxes in coral reef fishes, focusing on four key frameworks: demographic modelling, bioenergetics, micronutrients, and compound-specific stable isotope analysis (CSIA). Each framework can be integrated with underwater surveys, enabling researchers to scale organismal processes to ecosystem properties. This has revealed how small fish support biomass turnover, pelagic subsidies sustain fisheries, and fisheries benefit human health. Combining frameworks, closing data gaps, and expansion to other aquatic ecosystems can advance understanding of how fishes contribute to ecosystem functions and services.

The importance of oxygen for explaining rapid shifts in a marine fish

Large-scale shifts in marine species biogeography have been a notable impact of climate change. An effective explanation of what drives these species shifts, as well as accurate predictions of where they might move, is crucial to effectively managing these natural resources and conserving biodiversity. While temperature has been implicated as a major driver of these shifts, physiological processes suggest that oxygen, prey, and other factors should also play important roles. We expanded upon previous temperature-based distribution models by testing whether oxygen, food web productivity, salinity, and scope for metabolic activity (the Metabolic Index) better explained the changing biogeography of Black Sea Bass (Centropristis striata) in the Northeast US. This species has been expanding further north over the past 15 years. We found that oxygen improved model performance beyond a simple consideration of temperature (ΔAIC = 799, ΔTSS = 0.015), with additional contributions from prey and salinity. However, the Metabolic Index did not substantially increase model performance relative to temperature and oxygen (ΔAIC = 0.63, ΔTSS = 0.0002). Marine species are sensitive to oxygen, and we encourage researchers to use ocean biogeochemical hindcast and forecast products to better understand marine biogeographic changes.

Climate change affects the distribution of diversity across marine food webs

Many studies predict shifts in species distributions and community size composition in response to climate change, yet few have demonstrated how these changes will be distributed across marine food webs. We use Bayesian Additive Regression Trees to model how climate change will affect the habitat suitability of marine fish species across a range of body sizes and belonging to different feeding guilds, each with different habitat and feeding requirements in the northeast Atlantic shelf seas. Contrasting effects of climate change are predicted for feeding guilds, with spatially extensive decreases in the species richness of consumers lower in the food web (planktivores) but increases for those higher up (piscivores). Changing spatial patterns in predator-prey mass ratios and fish species size composition are also predicted for feeding guilds and across the fish assemblage. In combination, these changes could influence nutrient uptake and transformation, transfer efficiency and food web stability, and thus profoundly alter ecosystem structure and functioning.

Brief floodplain inundation provides growth and survival benefits to a young-of-year fish in an intermittent river threatened by water development

Riverine floodplains are highly productive habitats that often act as nurseries for fish but are threatened by flow regulation. The Fitzroy River in northern Australia is facing development, but uncertainty exists regarding the extent to which floodplain habitats deliver benefits to fish, particularly given the brevity of seasonal floodplain inundation. We investigated the growth rate of young-of-year bony bream (Nematalosa erebi) in main channel and ephemeral floodplain habitats using age derived from otolith daily increments. We also investigated potential mechanisms influencing growth and modelled the consequences of differential growth rate on survival. Our results revealed higher growth occurred exclusively on the floodplain and that zooplankton biomass was the best predictor of growth rate. Modelling indicated that elevated growth rate in high-growth floodplain pools (top 25th percentile) could translate into substantial increases in survivorship. The positive effect of zooplankton biomass on growth was moderated under highly turbid conditions. Temperature had a minor influence on growth, and only in floodplain habitats. Our results indicate ephemeral floodplain habitats can deliver substantial growth and survival benefits to young-of-year fish even when floodplain inundation is brief. This study highlights the need to ensure that water policy safeguards floodplain habitats due to their important ecological role.

phylosem: A fast and simple R package for phylogenetic inference and trait imputation using phylogenetic structural equation models

Phylogenetic comparative methods (PCMs) can be used to study evolutionary relationships and trade-offs among species traits. Analysts using PCM may want to (1) include latent variables, (2) estimate complex trait interdependencies, (3) predict missing trait values, (4) condition predicted traits upon phylogenetic correlations and (5) estimate relationships as slope parameters that can be compared with alternative regression methods. The Comprehensive R Archive Network (CRAN) includes well-documented software for phylogenetic linear models (phylolm), phylogenetic path analysis (phylopath), phylogenetic trait imputation (Rphylopars) and structural equation models (sem), but none of these can simultaneously accomplish all five analytical goals. We therefore introduce a new package phylosem for phylogenetic structural equation models (PSEM) and summarize features and interface. We also describe new analytical options, where users can specify any combination of Ornstein-Uhlenbeck, Pagel's-δ and Pagel's-λ transformations for species covariance. For the first time, we show that PSEM exactly reproduces estimates (and standard errors) for simplified cases that are feasible in sem, phylopath, phylolm and Rphylopars and demonstrate the approach by replicating a well-known case study involving trade-offs in plant energy budgets.

Somatic Growth and Maturity for Four Species of River Cooter Including Pseudemys concinna suwanniensis, P. nelsoni, P. peninsularis, and P. texana

Pseudemys is a genus of commonly occurring freshwater turtles with limited growth information across their long lifespans. We used 11,361 mark-recapture events to estimate the somatic growth rates of P. nelsoni, P. peninsularis, P. concinna suwanniensis, and P. texana from freshwater springs and developed a Bayesian growth model to estimate the species-specific, site-specific, and individual effects on growth. We corroborated evidence for fast juvenile growth and slower adult growth in Pseudemys but found uncommonly fast growth rates, with turtles doubling or tripling in size in the first year. P. texana males had the smallest average maximum size (L∞, 243 mm), while P. c. suwanniensis females had the largest (423 mm). Environmental conditions at springs had significant effects on k, the growth coefficient, but not L∞. We derived, using a ratio of length at maturity to L∞ (71.7% and 87%, males and females), that females matured 1.15-1.57 times older than males except for P. c. suwanniensis, which matured three times older. Given the local abundance declines in many Pseudemys from anthropogenic impacts, this study provides important baseline life history information for Pseudemys species for use in ongoing conservation efforts and presents a novel hierarchical modeling approach using a long-term mark-recapture dataset.

Larger but younger fish when growth outpaces mortality in heated ecosystem

Ectotherms are predicted to 'shrink' with global warming, in line with general growth models and the temperature-size rule (TSR), both predicting smaller adult sizes with warming. However, they also predict faster juvenile growth rates and thus larger size-at-age of young organisms. Hence, the result of warming on the size-structure of a population depends on the interplay between how mortality rate, juvenile- and adult growth rates are affected by warming. Here, we use two-decade long time series of biological samples from a unique enclosed bay heated by cooling water from a nearby nuclear power plant to become 5-10 °C warmer than its reference area. We used growth-increment biochronologies (12,658 reconstructed length-at-age estimates from 2426 individuals) to quantify how >20 years of warming has affected body growth, size-at-age, and catch to quantify mortality rates and population size- and age structure of Eurasian perch (Perca fluviatilis). In the heated area, growth rates were faster for all sizes, and hence size-at-age was larger for all ages, compared to the reference area. While mortality rates were also higher (lowering mean age by 0.4 years), the faster growth rates lead to a 2 cm larger mean size in the heated area. Differences in the size-spectrum exponent (describing how the abundance declines with size) were less clear statistically. Our analyses reveal that mortality, in addition to plastic growth and size-responses, is a key factor determining the size structure of populations exposed to warming. Understanding the mechanisms by which warming affects the size- and the age structure of populations is critical for predicting the impacts of climate change on ecological functions, interactions, and dynamics.

Isolation-by-distance and isolation-by-oceanography in Maroon Anemonefish (Amphiprion biaculeatus)

Obtaining dispersal estimates for a species is key to understanding local adaptation and population dynamics and to implementing conservation actions. Genetic isolation-by-distance (IBD) patterns can be used for estimating dispersal, and these patterns are especially useful for marine species in which few other methods are available. In this study, we genotyped coral reef fish (Amphiprion biaculeatus) at 16 microsatellite loci across eight sites across 210 km in the central Philippines to generate fine-scale estimates of dispersal. All sites except for one followed IBD patterns. Using IBD theory, we estimated a larval dispersal kernel spread of 8.9 km (95% confidence interval of 2.3-18.4 km). Genetic distance to the remaining site correlated strongly with the inverse probability of larval dispersal from an oceanographic model. Ocean currents were a better explanation for genetic distance at large spatial extents (sites greater than 150 km apart), while geographic distance remained the best explanation for spatial extents less than 150 km. Our study demonstrates the utility of combining IBD patterns with oceanographic simulations to understand connectivity in marine environments and to guide marine conservation strategies.

Optimal energy allocation trade-off driven by size-dependent physiological and demographic responses to warming

Body size-dependent physiological effects of temperature influence individual growth, reproduction, and survival, which govern animal population responses to global warming. Considerable knowledge has been established on how such effects can affect population growth and size structure, but less is known of their potential role in temperature-driven adaptation in life-history traits. In this study, we ask how warming affects the optimal allocation of energy between growth and reproduction and disentangle the underlying fitness trade-offs. To this end, we develop a novel dynamic energy budget integral projection model (DEB-IPM), linking individuals' size- and temperature-dependent consumption and maintenance via somatic growth, reproduction, and size-dependent energy allocation to emergent population responses. At the population level, we calculate the long-term population growth rate (fitness) and stable size structure emerging from demographic processes. Applying the model to an example of pike (Esox lucius), we find that optimal energy allocation to growth decreases with warming. Furthermore, we demonstrate how growth, fecundity, and survival contribute to this change in optimal allocation. Higher energy allocation to somatic growth at low temperatures increases fitness through survival of small individuals and through the reproduction of larger individuals. In contrast, at high temperatures, increased allocation to reproduction is favored because warming induces faster somatic growth of small individuals and increased fecundity but reduced growth and higher mortality of larger individuals. Reduced optimum allocation to growth leads to further reductions in body size and an increasingly truncated population size structure with warming. Our study demonstrates how, by incorporating general physiological mechanisms driving the temperature dependence of life-history traits, the DEB-IPM framework is useful for investigating the adaptation of size-structured organisms to warming.

Temperature impacts on fish physiology and resource abundance lead to faster growth but smaller fish sizes and yields under warming

Resolving the combined effect of climate warming and exploitation in a food web context is key for predicting future biomass production, size-structure and potential yields of marine fishes. Previous studies based on mechanistic size-based food web models have found that bottom-up processes are important drivers of size-structure and fisheries yield in changing climates. However, we know less about the joint effects of 'bottom-up' and physiological effects of temperature; how do temperature effects propagate from individual-level physiology through food webs and alter the size-structure of exploited species in a community? Here, we assess how a species-resolved size-based food web is affected by warming through both these pathways and by exploitation. We parameterize a dynamic size spectrum food web model inspired by the offshore Baltic Sea food web, and investigate how individual growth rates, size-structure, and relative abundances of species and yields are affected by warming. The magnitude of warming is based on projections by the regional coupled model system RCA4-NEMO and the RCP 8.5 emission scenario, and we evaluate different scenarios of temperature dependence on fish physiology and resource productivity. When accounting for temperature-effects on physiology in addition to on basal productivity, projected size-at-age in 2050 increases on average for all fish species, mainly for young fish, compared to scenarios without warming. In contrast, size-at-age decreases when temperature affects resource dynamics only, and the decline is largest for young fish. Faster growth rates due to warming, however, do not always translate to larger yields, as lower resource carrying capacities with increasing temperature tend to result in decline in the abundance of larger fish and hence spawning stock biomass. These results suggest that to understand how global warming affects the size structure of fish communities, both direct metabolic effects and indirect effects of temperature via basal resources must be accounted for.

Mechanistic Temperature-Size Rule Explanation Should Reconcile Physiological and Mortality Responses to Temperature

AbstractThe temperature-size rule is one of the universal rules in ecology and states that ectotherms in warmer waters will grow faster as juveniles, mature at smaller sizes and younger ages, and reach smaller maximum body sizes. Many models have unsuccessfully attempted to reproduce temperature-size rule-consistent life histories by using two-term (anabolism and catabolism) Pütter-type growth models, such as the von Bertalanffy. Here, we present a physiologically structured individual growth model, which incorporates an energy budget and optimizes energy allocation to growth, reproduction, and reserves. Growth, maturation, and reproductive output emerge as a result of life-history optimization to specific physiological rates and mortality conditions. To assess which processes can lead to temperature-size rule-type life histories, we simulate 42 scenarios that differ in temperature and body size dependencies of intake, metabolism, and mortality rates. Results show that the temperature-size rule can emerge in two ways. The first way requires both intake and metabolism to increase with temperature, but the temperature-body size interaction of the two rates must lead to relatively faster intake increase in small individuals and relatively larger metabolism increase in large ones. The second way requires only higher temperature-driven natural mortality and faster intake rates in early life (no change in metabolic rates is needed). This selects for faster life histories with earlier maturation and increased reproductive output. Our model provides a novel mechanistic and evolutionary framework for identifying the conditions necessary for the temperature-size rule. It shows that the temperature-size rule is likely to reflect both physiological changes and life-history optimization and that use of von Bertalanffy-type models, which do not include reproduction processes, can hinder our ability to understand and predict ectotherm responses to climate change.

Sharkipedia: a curated open access database of shark and ray life history traits and abundance time-series

A curated database of shark and ray biological data is increasingly necessary both to support fisheries management and conservation efforts, and to test the generality of hypotheses of vertebrate macroecology and macroevolution. Sharks and rays are one of the most charismatic, evolutionary distinct, and threatened lineages of vertebrates, comprising around 1,250 species. To accelerate shark and ray conservation and science, we developed Sharkipedia as a curated open-source database and research initiative to make all published biological traits and population trends accessible to everyone. Sharkipedia hosts information on 58 life history traits from 274 sources, for 170 species, from 39 families, and 12 orders related to length (n = 9 traits), age (8), growth (12), reproduction (19), demography (5), and allometric relationships (5), as well as 871 population time-series from 202 species. Sharkipedia relies on the backbone taxonomy of the IUCN Red List and the bibliography of Shark-References. Sharkipedia has profound potential to support the rapidly growing data demands of fisheries management, international trade regulation as well as anchoring vertebrate macroecology and macroevolution.

A functional vulnerability framework for biodiversity conservation

Setting appropriate conservation strategies in a multi-threat world is a challenging goal, especially because of natural complexity and budget limitations that prevent effective management of all ecosystems. Safeguarding the most threatened ecosystems requires accurate and integrative quantification of their vulnerability and their functioning, particularly the potential loss of species trait diversity which imperils their functioning. However, the magnitude of threats and associated biological responses both have high uncertainties. Additionally, a major difficulty is the recurrent lack of reference conditions for a fair and operational measurement of vulnerability. Here, we present a functional vulnerability framework that incorporates uncertainty and reference conditions into a generalizable tool. Through in silico simulations of disturbances, our framework allows us to quantify the vulnerability of communities to a wide range of threats. We demonstrate the relevance and operationality of our framework, and its global, scalable and quantitative comparability, through three case studies on marine fishes and mammals. We show that functional vulnerability has marked geographic and temporal patterns. We underline contrasting contributions of species richness and functional redundancy to the level of vulnerability among case studies, indicating that our integrative assessment can also identify the drivers of vulnerability in a world where uncertainty is omnipresent.

Movement and mortality of invasive suckermouth armored catfish during a spearfishing control experiment

Control of non-native, invasive species in groundwater-dependent ecosystems that are also inhabited by regionally endemic or at-risk species represents a key challenge in aquatic invasive species management. Non-native suckermouth armored catfish (SAC; family Loricariidae) have invaded freshwater ecosystems on a global scale, including the groundwater-dependent upper San Marcos River in Texas, USA. We used passive integrated transponder tags to follow the movements and fates of 65 fish in a 1.6 km spring-fed reach of the upper San Macros River to assess the efficacy of a community-based spearfishing bounty hunt for controlling SAC. We found the weekly probability of SAC survival was negatively correlated with the number of fish removed as a part of the bounty hunt each week (P = 0.003, R² = 0.86), while the probability of SAC being speared and reported was positively correlated with the number of fish removed (P = 0.011, R² = 0.53). The majority of SAC used < 25 m² of river over a nine-week tracking period, but the area of river fish used correlated positively with the number of relocations (P < 0.001, R² = 0.36) as might be expected for a population that disperses through diffusive spread. These findings collectively suggest local-scale suppression of the SAC population is possible through community engagement in spearfishing, but over longer time periods immigration might offset some of the removal success. This conclusion provides an explanation for the pattern in which long-term spearfishing tournaments have reduced biomass but ultimately not resulted in eradication of the population.

Maximization of fitness by phenological and phenotypic plasticity in range expanding rabbitfish (Siganidae)

Global warming is modifying the phenology, life‐history traits and biogeography of species around the world. Evidence of these effects have increased over recent decades; however, we still have a poor understanding of the possible outcomes of their interplay across global climatic gradients, hindering our ability to accurately predict the consequences of climate change in populations and ecosystems.

We examined the effect that changes in biogeography can have on the life‐history traits of two of the most successful range‐extending fish species in the world: the tropical rabbitfishes Siganus fuscescens and Siganus rivulatus. Both species have established abundant populations at higher latitudes in the northern and southern hemispheres and have been identified as important ecological engineers with the potential to alter the community structure of seaweed forests (Laminariales and Fucales) in temperate regions.

Life‐history trait information from across their global distribution was compiled from the published literature and meta‐analyses were conducted to assess changes in (i) the onset and duration of reproductive periods, (ii) size at maturity, (iii) fecundity, (iv) growth rates, (v) maximum body sizes and (vi) longevity in populations at the leading edge of range expansion in relation to sea surface temperature and primary productivity (a common proxy for nutritional resource levels).

Populations at highest latitudes had shortened their reproductive periods and reduced growth rates, taking longer to reach sexual maturity and maximum sizes, but compensated this with higher fecundity per length class and longer lifespans than populations in warmer environments. Low primary productivity and temperature in the Mediterranean Sea resulted in lower growth rates and body sizes for S. rivulatus, but also lower length at maturity, increasing life‐time reproductive output.

The results suggest that plasticity in the phenology and life‐history traits of range‐expanding species would be important to enhance their fitness in high latitude environments, facilitating their persistence and possible further poleward expansions. Quantifying the magnitude and direction of these responses can improve our understanding and ability to forecast species redistributions and its repercussions in the functioning of temperate ecosystems.

Expanding ocean food production under climate change

As the human population and demand for food grow¹, the ocean will be called on to provide increasing amounts of seafood. Although fisheries reforms and advances in offshore aquaculture (hereafter 'mariculture') could increase production², the true future of seafood depends on human responses to climate change³. Here we investigated whether coordinated reforms in fisheries and mariculture could increase seafood production per capita under climate change. We find that climate-adaptive fisheries reforms will be necessary but insufficient to maintain global seafood production per capita, even with aggressive reductions in greenhouse-gas emissions. However, the potential for sustainable mariculture to increase seafood per capita is vast and could increase seafood production per capita under all but the most severe emissions scenario. These increases are contingent on fisheries reforms, continued advances in feed technology and the establishment of effective mariculture governance and best practices. Furthermore, dramatically curbing emissions is essential for reducing inequities, increasing reform efficacy and mitigating risks unaccounted for in our analysis. Although climate change will challenge the ocean's ability to meet growing food demands, the ocean could produce more food than it does currently through swift and ambitious action to reduce emissions, reform capture fisheries and expand sustainable mariculture operations.

Climate change linked to functional homogenization of a subtropical estuarine system

Climate change causes marine species to shift and expand their distributions, often leading to changes in species diversity. While increased biodiversity is often assumed to confer positive benefits on ecosystem functioning, many examples have shown that the relationship is specific to the ecosystem and function studied and is often driven by functional composition and diversity. In the northwestern Gulf of Mexico, tropical species expansion was shown to have increased estuarine fish and invertebrate diversity; however, it is not yet known how those increases have affected functional diversity. To address this knowledge gap, two metrics of functional diversity, functional richness (FRic) and functional dispersion (FDis), were estimated in each year for a 38‐year study period, for each of the eight major bays along the Texas coast. Then, the community‐weighted mean (CWM) trait values for each of the functional traits are calculated to assess how functional composition has changed through time. Finally, principal component analysis (PCA) was used to identify species contributing most to changing functional diversity. We found significant increases in log‐functional richness in both spring and fall, and significant decreases in functional dispersion in spring, suggesting that although new functional types are entering the bays, assemblages are becoming more dominated by similar functional types. Community‐weighted trait means showed significant increases in the relative abundance of traits associated with large, long‐lived, higher trophic level species, suggesting an increase in periodic and equilibrium life‐history strategists within the bays. PCA identified mainly native sciaenid species as contributing most to functional diversity trends although several tropical species also show increasing trends through time. We conclude that the climate‐driven species expansion in the northwestern Gulf of Mexico led to a decrease in functional dispersion due to increasing relative abundance of species with similar life‐history characteristics, and thus the communities have become more functionally homogeneous.

Exceptional longevity in a lightly exploited, semi-anadromous clupeid (Perth herring Nematalosa vlaminghi) within a degraded estuarine environment

Many anadromous (and semi-anadromous) fish species, which migrate from marine to freshwater ecosystems to spawn and to complete their life cycle, are currently threatened by habitat degradation in the upper parts of estuaries and rivers, where spawning and juvenile nursery areas occur. This situation pertains to Nematalosa vlaminghi, a semi-anadromous gizzard shad (Clupeidae: Dorosomatinae) endemic to south-western Australia. More information on the biology of N. vlaminghi is required for its effective management and conservation. This study estimated growth, longevity and natural mortality of N. vlaminghi. Ages were determined by counting validated annual growth increments in thin sections of sagittal otoliths. Fish were sampled in the Swan-Canning Estuary, which historically hosted the main commercial fishery for N. vlaminghi. Since the late 1990s, however, only very minor catches of this species have been taken from this estuary and none since 2007. Given the essentially unexploited state of the current population, the estimate of total mortality (Z, y^-1 ) from the catch curve analysis in this study provides a direct estimate of natural mortality (M, y^-1 ) for N. vlaminghi. Somatic growth during this study was substantially slower than that historically reported for N. vlaminghi. Various processes operating in this estuary since the 1970s may have contributed to slower growth, including increased hypoxia, higher primary productivity due to eutrophication and cessation of fishing for N. vlaminghi. The maximum observed age of 19.8 years for N. vlaminghi is the highest reported for any gizzard shad globally and one of the highest reported for any clupeid species. This exceptional longevity is likely part of a life-history strategy that allows N. vlaminghi, which exhibits substantial variation in annual recruitment success, to persist in the intermittently closed estuaries of south-western Australia where environmental factors, including low flow and hypoxia, can create unfavourable conditions for reproduction for extended periods.

Decline in Atlantic wolffish Anarhichas lupus in the North Sea: Impacts of fishing pressure and climate change

Anarhichas lupus is a boreo-Arctic species with biological characteristics often associated with vulnerability to overexploitation. Although not commercially targeted in the North Sea, A. lupus is a bycatch species in mixed demersal fisheries. Here we provide an overview of the status of A. lupus in the North Sea, as observed from commercial landings and fishery-independent trawl survey data. A. lupus was once common across much of the central and northern North Sea but, since the 1980s, have declined in abundance, demographic characteristics (reduced size) and geographical range, with the shallower and more southerly parts of its range most impacted. A. lupus is still relatively frequent in the northern North Sea, where fishing intensity, though decreasing, is high. Bycatch through fishing remains a potential threat and, considering the likely impacts of predicted climate change on cold-water species, risks of further regional depletion and/or range contraction remain. Whether or not A. lupus is able to re-establish viable populations in former habitat in UK coastal waters is unknown. Given the lack of data, the precautionary principle would suggest that manageable pressures be minimized where the species and its habitat are at risk of further impacts, and more regular assessments of population status be undertaken.

Decadal shifts in traits of reef fish communities in marine reserves

Marine reserves are known to impact the biomass, biodiversity, and functions of coral reef fish communities, but the effect of protective management on fish traits is less explored. We used a time-series modelling approach to simultaneously evaluate the abundance, biomass, and traits of eight fish families over a chronosequence spanning 44 years of protection. We constructed a multivariate functional space based on six traits known to respond to management or disturbance and affect ecosystem processes: size, diet, position in the water column, gregariousness, reef association, and length at maturity. We show that biomass increased with a log-linear trend over the time-series, but abundance only increased after 20 years of closure, and with more variation among reserves. This difference is attributed to recovery rates being dependent on body sizes. Abundance-weighted traits and the associated multivariate space of the community change is driven by increased proportions over time of the trait categories: 7-15 cm body size; planktivorous; species low in the water column; medium-large schools; and species with high levels of reef association. These findings suggest that the trait compositions emerging after the cessation of fishing are novel and dynamic.

Assessing the population-level conservation effects of marine protected areas

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 their borders. A network of MPAs covering roughly 20% of the Channel Islands National Marine Sanctuary was established in 2003, with a goal of providing regional conservation and fishery benefits. We used a spatially explicit bioeconomic simulation model and a Bayesian difference-in-difference regression to examine the conditions under which MPAs can provide population-level conservation benefits inside and outside their borders and to assess evidence of those benefits in the Channel Islands. As of 2017, we estimated that biomass densities of targeted fin-fish had a median value 81% higher (90% credible interval: 23-148) inside the Channel Island MPAs than outside. However, we found no clear effect of these MPAs on mean total biomass densities at the population level: estimated median effect was -7% (90% credible interval: -31 to 23) from 2015 to 2017. Our simulation model showed that effect sizes of MPAs of <30% were likely to be difficult to detect (even when they were present); smaller effect sizes (which are likely to be common) were even harder to detect. Clearly, communicating expectations and uncertainties around MPAs is critical to ensuring that MPAs are effective. We provide a novel assessment of the population-level effects of a large MPA network across many different species of targeted fin-fish, and our results offer guidance for communities charged with monitoring and adapting MPAs.

Effects of Warming on Intraguild Predator Communities with Ontogenetic Diet Shifts

AbstractSpecies interactions mediate how warming affects community composition via individual growth and population size structure. While predictions on how warming affects composition of size- or stage-structured communities have so far focused on linear (food chain) communities, mixed competition-predation interactions, such as intraguild predation, are common. Intraguild predation often results from changes in diet over ontogeny ("ontogenetic diet shifts") and strongly affects community composition and dynamics. Here, we study how warming affects a community of intraguild predators with ontogenetic diet shifts, consumers, and shared prey by analyzing a stage-structured bioenergetics multispecies model with temperature- and body size-dependent individual-level rates. We find that warming can strengthen competition and decrease predation, leading to a loss of a cultivation mechanism (the feedback between predation on and competition with consumers exerted by predators) and ultimately predator collapse. Furthermore, we show that the effect of warming on community composition depends on the extent of the ontogenetic diet shift and that warming can cause a sequence of community reconfigurations in species with partial diet shifts. Our findings contrast previous predictions concerning individual growth of predators and the mechanisms behind predator loss in warmer environments and highlight how feedbacks between temperature and intraspecific size structure are important for understanding such effects on community composition.

Reuse and recycle: Integrating aquaculture and agricultural systems to increase production and reduce nutrient pollution

Integrated agriculture and aquaculture systems (IAAS) allow nutrients, energy, and water to flow throughout the components of the system, increasing the efficiency with which inputs are converted to food. Yet effectively designing an IAAS requires understanding how nutrients accumulate and alter the system's productivity. Here we developed a mechanistic model for nitrogen transport and utilization and parameterized it using the IAAS in He'eia, Hawai'i. Of note, we modeled tidal influence, which extends existing IAAS models that often assume aquaculture in tank enclosures. We simulated the impact of nitrogen loading from three possible land use scenarios across agriculture and development priorities on the productivity of the fishpond downstream. We projected that organic nitrogen and nitrate concentrations parallel the successive increases in nitrogen loading across management strategies. Autotroph and fish densities were predicted to follow similar trends in response to increased nitrogen availability, causing fish harvests to increase from the current land use (25 kg/ha) to the restored agriculture (35 kg/ha) and urban (50 kg/ha) alternatives. While fish harvests were predicted to be highest in the urban scenario, modeled caloric production in the restored scenario from agriculture and aquaculture would sustain 235 people (4.3 people/ha) in the He'eia IAAS, 16 and 125 times more than the current or urban land uses, respectively. Restoring diversified agriculture was also predicted to retain a larger proportion of nitrogen inputs (0.43) than urbanizing the region (0.30), which would reduce nitrogen export to the adjacent Kāne'ohe Bay. Several state variables were notably sensitive to tidal flux rates, highlighting the importance of incorporating tidal dynamics into a coastal IAAS model. This model provides valuable insights for the management of existing coastal IAAS and design of new IAAS in coastal regions to improve the sustainability of future food systems.

Bridging gaps in demographic analysis with phylogenetic imputation

Phylogenetically informed imputation methods have rarely been applied to estimate missing values in demographic data but may be a powerful tool for reconstructing vital rates of survival, maturation, and fecundity for species of conservation concern. Imputed vital rates could be used to parameterize demographic models to explore how populations respond when vital rates are perturbed. We used standardized vital rate estimates for 50 bird species to assess the use of phylogenetic imputation to fill gaps in demographic data. We calculated imputation accuracy for vital rates of focal species excluded from the data set either singly or in combination and with and without phylogeny, body mass, and life-history trait data. We used imputed vital rates to calculate demographic metrics, including generation time, to validate the use of imputation in demographic analyses. Covariance among vital rates and other trait data provided a strong basis to guide imputation of missing vital rates in birds, even in the absence of phylogenetic information. Mean NRMSE for null and phylogenetic models differed by <0.01 except when no vital rates were available or for vital rates with high phylogenetic signal (Pagel's λ > 0.8). In these cases, including body mass and life-history trait data compensated for lack of phylogenetic information: mean normalized root mean square error (NRMSE) for null and phylogenetic models differed by <0.01 for adult survival and <0.04 for maturation rate. Estimates of demographic metrics were sensitive to the accuracy of imputed vital rates. For example, mean error in generation time doubled in response to inaccurate estimates of maturation time. Accurate demographic data and metrics, such as generation time, are needed to inform conservation planning processes, for example through International Union for Conservation of Nature Red List assessments and population viability analysis. Imputed vital rates could be useful in this context but, as for any estimated model parameters, awareness of the sensitivities of demographic model outputs to the imputed vital rates is essential.

Biological Knowledge of Thornback Ray (Raja clavata) from the Azores: Improving Scientific Information for the Effectiveness of Species-Specific Management Measures

Simple Summary

Sharks, rays, and skates are increasingly being recognized as endangered due to their life-history characteristics, fishing pressure, and habitat degradation. The thornback ray Raja clavata is one of the most commercially important skates in the seas of Northwest Europe. However, due to a lack of biological knowledge about this species in Azorean waters, the types of stock evaluations that can be performed are restricted. This study expands current knowledge on vertical distribution, size-frequency distributions, growth patterns, sex ratios, mortality rates, and reproduction of this species, and provides a baseline for further fishing monitoring.

Abstract

Elasmobranchs are globally recognized as vulnerable due to their life-history characteristics, fishing pressure, and habitat degradation. Among the skates and rays caught by commercial fisheries, the thornback ray Raja clavata is one of the most economically important in Northwest European seas. However, the scarcity of biological knowledge about this species in Azorean waters has limited the stock assessment types that can be conducted. To improve information on its habitat preferences, spatial distribution and movement pattern, growth, sex ratio, mortality, and reproduction, as well as to investigate long-term changes in abundance and size, this study analyzed approximately 25 years of fishery-dependent and independent data from the Azores. Raja clavata was mainly caught at depths up to 250 m. Most of the tagged fish were recaptured near the release point. A larger–deeper trend was found, and females were larger and more abundant than males. Life-history parameters showed that R. clavata has a long lifespan, large size, slow growth, and low natural mortality. The sustainability of its population is of concern to fisheries management and, while our findings suggested a relatively healthy stock in the Azores, a thorough increase in data quality is required to better understand the stock condition and prevent overexploitation.

The metabolic pace of life histories across fishes

All life acquires energy through metabolic processes and that energy is subsequently allocated to life-sustaining functions such as survival, growth and reproduction. Thus, it has long been assumed that metabolic rate is related to the life history of an organism. Indeed, metabolic rate is commonly believed to set the pace of life by determining where an organism is situated along a fast-slow life-history continuum. However, empirical evidence of a direct interspecific relationship between metabolic rate and life histories is lacking, especially for ectothermic organisms. Here, we ask whether three life-history traits-maximum body mass, generation length and growth performance-explain variation in resting metabolic rate (RMR) across fishes. We found that growth performance, which accounts for the trade-off between growth rate and maximum body size, explained variation in RMR, yet maximum body mass and generation length did not. Our results suggest that measures of life history that encompass trade-offs between life-history traits, rather than traits in isolation, explain variation in RMR across fishes. Ultimately, understanding the relationship between metabolic rate and life history is crucial to metabolic ecology and has the potential to improve prediction of the ecological risk of data-poor species.

Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora Moro)

Simple Summary

The growing scarcity of continental shelf and epipelagic oceanic fishes has led to commercial fishing in deeper waters. With this spatial expansion in fishing efforts, some vulnerable deep-sea species have been increasingly captured. To reduce fishing-induced impacts on these resources, information on population traits is required by fishery scientists to produce adequate management advice. In the Northeast Atlantic, the common mora Mora moro has become the main fish species caught by bottom longliners operating in deep waters between 600 and 1200 m. Information about the biology and exploitation status of this species is scarce. This study unravels and highlights important and crucial aspects of the habitat preferences, life-history traits (sex ratio, timing of reproduction, size at maturity, growth pattern, and mortality rates), size structure, and abundance of the M. moro based on scientific surveys and commercial fisheries in the Azores region. Results highlight its vulnerability to overfishing due to its large size, slow growth, low natural mortality, long life span, and late maturity.

Abstract

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

Strengths and weaknesses in the long-term sustainability of two sympatric seabreams (Argyrops spinifer and Rhabdosargus haffara, Sparidae)

Argyrops spinifer and Rhabdosargus haffara are two sympatric seabream species making important contributions to fisheries landings in the western Arabian/Persian Gulf. We identified the strengths and weaknesses in the long-term sustainability of A. spinifer and R. haffara stocks by integrating multiple sources of data, including fisheries catch and effort statistics, life history traits, scientific trawl surveys and historical length frequency distribution. Four strengths were identified in A. spinifer: wide distribution of juveniles, positive association to the network of de facto fishing exclusion areas created by hundreds of oil-gas facilities, early maturation and the existence of large and old individuals. A. spinifer suffers from two potential weaknesses: slow growth rate and higher exploitation pressure on the small-sized individuals. R. haffara, on the other hand, has a strength of having a short life span and a fast growth rate, characteristics that make it robust to unfavourable conditions. R. haffara suffers from two weaknesses: the lack of association to the oil and gas facilities, and the preference for nearshore shallow waters with stronger negative anthropogenic impacts. Identified strengths and weaknesses of these two sparids provided a preliminary assessment about their long-term sustainability, as well as a roadmap about how to develop different management strategies to meet specific objectives.

Protecting the global ocean for biodiversity, food and climate

The ocean contains unique biodiversity, provides valuable food resources and is a major sink for anthropogenic carbon. Marine protected areas (MPAs) are an effective tool for restoring ocean biodiversity and ecosystem services1,2, but at present only 2.7% of the ocean is highly protected3. This low level of ocean protection is due largely to conflicts with fisheries and other extractive uses. To address this issue, here we developed a conservation planning framework to prioritize highly protected MPAs in places that would result in multiple benefits today and in the future. We find that a substantial increase in ocean protection could have triple benefits, by protecting biodiversity, boosting the yield of fisheries and securing marine carbon stocks that are at risk from human activities. Our results show that most coastal nations contain priority areas that can contribute substantially to achieving these three objectives of biodiversity protection, food provision and carbon storage. A globally coordinated effort could be nearly twice as efficient as uncoordinated, national-level conservation planning. Our flexible prioritization framework could help to inform both national marine spatial plans4 and global targets for marine conservation, food security and climate action.

Life histories determine divergent population trends for fishes under climate warming

Most marine fish species express life-history changes across temperature gradients, such as faster growth, earlier maturation, and higher mortality at higher temperature. However, such climate-driven effects on life histories and population dynamics remain unassessed for most fishes. For 332 Indo-Pacific fishes, we show positive effects of temperature on body growth (but with decreasing asymptotic length), reproductive rates (including earlier age-at-maturation), and natural mortality for all species, with the effect strength varying among habitat-related species groups. Reef and demersal fishes are more sensitive to temperature changes than pelagic and bathydemersal fishes. Using a life table, we show that the combined changes of life histories upon increasing temperature tend to facilitate population growth for slow life-history populations, but reduce it for fast life-history ones. Within our data, lower proportions (25-30%) of slow life-history fishes but greater proportions of fast life-history fishes (42-60%) show declined population growth rates under 1 °C warming. Together, these findings suggest prioritizing sustainable management for fast life-history species.

Uncovering unique plasticity in life history of an endangered centenarian fish

The ability to adapt to changing environments is fundamental for species persistence. Both plasticity and genetic selection are potential drivers that allow for traits to be advantageous, thus leading to increases in survival or fitness. Identifying phenotypic plasticity in life history traits of long-lived organisms can be difficult owing to high survival, long generation times, and few studies at sufficient spatial and temporal scales to elicit a plastic response within a population. To begin to understand phenotypic plasticity of a long-lived freshwater fish in response to environmental conditions, we used a long-term data set consisting of over 1,200 mark-recapture events to inform our understanding of dynamic rate functions and life history attributes. Furthermore, we used a common garden experimental approach to confirm whether changes in life history traits are in response to plasticity in the reaction norm or are genetically derived. Using these approaches, we demonstrated differences in life history traits among Pallid Sturgeon (Scaphirhynchus albus) occupying river segments of varying physical and hydrological stress. The common garden experiment corroborated plastic phenotypic expression in reaction norms for age at first maturity, longevity, fecundity, and maximum size. These growth-mediated attributes resulted in differences in overall fitness traits, where Pallid Sturgeon fecundity was greater than a tenfold difference and 3–6 times the number of life-time spawning events. Anthropogenic modifications to river form and function are likely responsible for the variation in life history attributes resulting from an increased metabolic demand for maintaining station, foraging, and migration. Collectively, our approach provided surprising insight into the capabilities of a centenarian fish to dramatically respond to a changing environment.

LeMaRns: A Length-based Multi-species analysis by numerical simulation in R

Fish stocks interact through predation and competition for resources, yet stocks are typically managed independently on a stock-by-stock basis. The need to take account of multi-species interactions is widely acknowledged. However, examples of the application of multi-species models to support management decisions are limited as they are often seen as too complex and lacking transparency. Thus there is a need for simple and transparent methods to address stock interactions in a way that supports managers. Here we introduce LeMaRns, a new R-package of a general length-structured fish community model, LeMans, that characterises fishing using fleets that can have different gears and species catch preferences. We describe the model, package implementation, and give three examples of use: determination of multi-species reference points; modelling of mixed-fishery interactions; and examination of the response of community indicators to dynamical changes in fleet effort within a mixed-fishery. LeMaRns offers a diverse array of options for parameterisation. This, along with the speed, comprehensive documentation, and open source nature of the package makes LeMans newly accessible, transparent, and easy to use, which we hope will lead to increased uptake by the fisheries management community.

An identification of invariants in life history traits of amphibians and reptiles

While many morphological, physiological, and ecological characteristics of organisms scale with body size, some do not change under size transformation. They are called invariant. A recent study recommended five criteria for identifying invariant traits. These are based on that a trait exhibits a unimodal central tendency and varies over a limited range with body mass (type I), or that it does not vary systematically with body mass (type II). We methodologically improved these criteria and then applied them to life history traits of amphibians, Anura, Caudata (eleven traits), and reptiles (eight traits). The numbers of invariant traits identified by criteria differed across amphibian orders and between amphibians and reptiles. Reproductive output (maximum number of reproductive events per year), incubation time, length of larval period, and metamorphosis size were type I and II invariant across amphibians. In both amphibian orders, reproductive output and metamorphosis size were type I and II invariant. In Anura, incubation time and length of larval period and in Caudata, incubation time were further type II invariant. In reptiles, however, only number of clutches per year was invariant (type II). All these differences could reflect that in reptiles body size and in amphibians, Anura, and Caudata metamorphosis (neotenic species go not through it) and the trend toward independence of egg and larval development from water additionally constrained life history evolution. We further demonstrate that all invariance criteria worked for amphibian and reptilian life history traits, although we corroborated some known and identified new limitations to their application.

Trait structure and redundancy determine sensitivity to disturbance in marine fish communities

Trait diversity is believed to influence ecosystem dynamics through links between organismal traits and ecosystem processes. Theory predicts that key traits and high trait redundancy-large species richness and abundance supporting the same traits-can buffer communities against environmental disturbances. While experiments and data from simple ecological systems lend support, large-scale evidence from diverse, natural systems under major disturbance is lacking. Here, using long-term data from both temperate (English Channel) and tropical (Seychelles Islands) fishes, we show that sensitivity to disturbance depends on communities' initial trait structure and initial trait redundancy. In both ecosystems, we found that increasing dominance by climatically vulnerable traits (e.g., small, fast-growing pelagics/corallivores) rendered fish communities more sensitive to environmental change, while communities with higher trait redundancy were more resistant. To our knowledge, this is the first study demonstrating the influence of trait structure and redundancy on community sensitivity over large temporal and spatial scales in natural systems. Our results exemplify a consistent link between biological structure and community sensitivity that may be transferable across ecosystems and taxa and could help anticipate future disturbance impacts on biodiversity and ecosystem functioning.

Life-history constraints on maximum population growth for loggerhead turtles in the northwest Atlantic

Conservation planning for protected species often relies on estimates of life-history parameters. A commonly used parameter is the instantaneous maximum population growth rate (r max) that can be used to limit removals and design recovery targets. Estimation of r max can be challenging because of limited availability of species- and population-specific data and life-history information. We applied a method proposed by Neil and Lebreton, originally developed for birds, to loggerhead turtles. The method uses age-at-first-reproduction and adult survival to estimate r max. We used a variety of datasets and matrix population models to confirm an allometric assumption required by the method, and to generate estimates of age-at-first-reproduction and adult survival. A meta-analysis was applied to parameters from reported growth curves, which were then combined with the size distribution of neophyte nesters to derive estimates of age-at-first-reproduction. Adult survival rates were obtained from an existing matrix population model. Monte Carlo simulation was then used to combine the estimates of the allometric coefficients, age-at-first-reproduction, and adult survival to obtain a probability distribution of approximate r max values. Estimated annual maximum population growth rates averaged 0.024, with a mode of 0.017 and a 95% highest density interval of 0.006-0.047. These estimates were similar to values reported by others using different methods and captured the variability in positive, annual change estimates across nesting beach sites for the northwest Atlantic loggerhead population. The use of life-history parameters has a long history in wildlife and fisheries management and conservation planning. Our estimates of r max, while having some biases and uncertainty, encompassed values presently used in recovery planning for loggerhead turtles and offer additional information for the management of endangered and threatened species.

Thermal stress induces persistently altered coral reef fish assemblages

Ecological communities are reorganizing in response to warming temperatures. For continuous ocean habitats this reorganization is characterized by large-scale species redistribution, but for tropical discontinuous habitats such as coral reefs, spatial isolation coupled with strong habitat dependence of fish species imply that turnover and local extinctions are more significant mechanisms. In these systems, transient marine heatwaves are causing coral bleaching and profoundly altering habitat structure, yet despite severe bleaching events becoming more frequent and projections indicating annual severe bleaching by the 2050s at most reefs, long-term effects on the diversity and structure of fish assemblages remain unclear. Using a 23-year time series spanning a thermal stress event, we describe and model structural changes and recovery trajectories of fish communities after mass bleaching. Communities changed fundamentally, with the new emergent communities dominated by herbivores and persisting for >15 years, a period exceeding realized and projected intervals between thermal stress events on coral reefs. Reefs which shifted to macroalgal states had the lowest species richness and highest compositional dissimilarity, whereas reefs where live coral recovered exceeded prebleaching fish richness, but remained dissimilar to prebleaching compositions. Given realized and projected frequencies of bleaching events, our results show that fish communities historically associated with coral reefs will not re-establish, requiring substantial adaptation by managers and resource users.

Global reconstruction of life-history strategies: A case study using tunas

Measuring the demographic parameters of exploited populations is central to predicting their vulnerability and extinction risk. However, current rates of population decline and species loss greatly outpace our ability to empirically monitor all populations that are potentially threatened.The scale of this problem cannot be addressed through additional data collection alone, and therefore it is a common practice to conduct population assessments based on surrogate data collected from similar species. However, this approach introduces biases and imprecisions that are difficult to quantify. Recent developments in hierarchical modelling have enabled missing values to be reconstructed based on the correlations between available life-history data, linking similar species based on phylogeny and environmental conditions.However, these methods cannot resolve life-history variability among populations or species that are closely placed spatially or taxonomically. Here, theoretically motivated constraints that align with life-history theory offer a new avenue for addressing this problem. We describe a Bayesian hierarchical approach that combines fragmented, multispecies and multi-population data with established life-history theory, in order to objectively determine similarity between populations based on trait correlations (life-history trade-offs) obtained from model fitting.We reconstruct 59 unobserved life-history parameters for 23 populations of tuna that sustain some of the world's most valuable fisheries. Testing by cross-validation across different scenarios indicated that life-histories were accurately reconstructed when information was available for other populations of the same species. The reconstruction of several traits was also accurate for species represented by a single population, although credible intervals increased dramatically. Synthesis and applications. The described Bayesian hierarchical method provides access to life-history traits that are difficult to measure directly and reconstructs missing life-history information useful for assessing populations and species that are directly or indirectly affected by human exploitation of natural resources. The method is particularly useful for examining populations that are spatially or taxonomically similar, and the reconstructed life-history strategies described for the principal market tunas have immediate application to the world-wide management of these fisheries.

Impacts of historical warming on marine fisheries production

Climate change is altering habitats for marine fishes and invertebrates, but the net effect of these changes on potential food production is unknown. We used temperature-dependent population models to measure the influence of warming on the productivity of 235 populations of 124 species in 38 ecoregions. Some populations responded significantly positively (n = 9 populations) and others responded significantly negatively (n = 19 populations) to warming, with the direction and magnitude of the response explained by ecoregion, taxonomy, life history, and exploitation history. Hindcasts indicate that the maximum sustainable yield of the evaluated populations decreased by 4.1% from 1930 to 2010, with five ecoregions experiencing losses of 15 to 35%. Outcomes of fisheries management—including long-term food provisioning—will be improved by accounting for changing productivity in a warmer ocean.

Predicting nutrient content of ray-finned fishes using phylogenetic information

Human food and nutrition security is dependent on marine ecosystems threatened by overfishing, climate change, and other processes. The consequences on human nutritional status are uncertain, in part because current methods of analyzing fish nutrient content are expensive. Here, we evaluate the possibility of predicting nutrient content of ray-finned fishes using existing phylogenetic and life history information. We focus on nutrients for which fish are important sources: protein, total fat, omega-3 and omega-6 fatty acids, iron, zinc, vitamin A, vitamin B12, and vitamin D. Our results show that life history traits are weak predictors of species nutrient content, but phylogenetic relatedness is associated with similar nutrient profiles. Further, we develop a method for predicting the nutrient content of 7500+ species based on phylogenetic relationships to species with known nutrient content. Our approach is a cost-effective means for estimating potential changes in human nutrient intake associated with altered access to ray-finned fishes.

Humans increasingly depend on seafood for nutrition, but nutrient content is unknown for the vast majority of fish species. Here, the authors use phylogenetic analyses and data imputation to predict the nutrient content of fish that are under-studied but that could be of future dietary importance.