Matthew Bryan Ogburn

Earth's biodiversity is distributed unevenly, typically peaking in warm, vegetated, and stable environments. This has frequently been linked to energy availability, which boosts productivity, bolsters populations, and facilitates coexistence. Here, we examine the relationship between energy and biodiversity across coastal oceans using particulate organic matter biogeochemistry and environmental DNA. We reveal that energy quantity (concentrations of carbon, nitrogen, and hydrolyzable amino acids) and salinity, two variables that co-vary with freshwater inflow, jointly predict species richness at regional and global scales. Biodiversity was lowest at sites and locations with high energy inflow and low salinity, suggesting that environmental filtering associated with the osmotic stress induced by freshwater inflow outweighs raw resource availability in governing species richness. Independent of this gradient, however, energy quality (defined via C:N ratios, δC values, and amino acid profiles) was associated with higher biodiversity. Labile, protein-rich, marine-derived resources supported higher biodiversity across all taxa at the regional scale, and a larger number of planktonic consumer taxa at both regional and global scales. High energy quality sites were also enriched in key planktonic groups such as calanoid and cyclopoid copepods, suggesting that these sites act as hotspots of planktonic biodiversity across coastal seascapes. Our findings suggest that few species can directly harness the plentiful resources provided by terrestrial subsidies in coastal oceans because they arrive in low salinity waters. In turn, high-quality food attracts a diverse range of consumers, which may seed the patchy foraging hotspots that characterize open-water food webs. Altered coastal hydrodynamics and biogeochemistry may therefore affect nearshore biodiversity, food webs, and fisheries.

Blue swimming crab ( Portunus pelagicus ) supports a valuable export fishery in Indonesia, currently estimated at over $400 million per year and employing over 250 thousand workers. High demand has led to the overexploitation of P. pelagicus in recent decades. However, accurately assessing stocks and harvest rates can be difficult. Variation in estimates of harvest sustainability among government, industry, and independent institutions highlights the need for comprehensive assessments. In this study, we examine the crab population in an artisanal nearshore fishery in Parepare Bay, South Sulawesi. We conducted a monthly analysis of the fishery for one year using two methods: (1) surveys of harvested crabs at a landing site and (2) collections of unharvested crabs from four sites in the bay using crab traps. From both methods, the average carapace width for male and female P. pelagicus was approximately 10 cm, and around half of the harvested crabs had not reached maturity. Estimates of spawning potential ratio for P. pelagicus in this fishery were 4%–9%, indicating overexploitation of the stock and impaired recruitment. As an additional aim, we examined the relative abundance of species in the crab community. We found that the bay is dominated by other species of swimming crab, namely Charybdis anisodon and Thalamita crenata . These other species may be predators of P. pelagicus , and high predation rates may further contribute to juvenile mortality in this stock. Achieving a sustainable harvest of P. pelagicus will likely require multiple actions such as enforcement of regulations, restocking of juveniles, and the restoration and protection of nearshore habitats.

With the rapid uptake of environmental DNA (eDNA) metabarcoding for a wide range of conservation and management uses, there is a growing need for guidance and best practices for species identification. A range of methodological and interpretive decisions influences taxa assignment. Here we provide a review and perspective of pitfalls and issues that can impact accurate taxonomic assignment across the full eDNA metabarcoding workflow: primer selection, lab handling, bioinformatics, taxonomic assignment, and communication of results. This paper addresses the complexities and challenges of the metabarcoding-based species identification process, offering recommendations for robust workflows and effective communication of findings. Accurate interpretation and communication of eDNA metabarcoding results requires an acknowledgment of methodological limitations such as incomplete reference databases, contamination risks, ambiguous sequences, and detection biases. Thus, we argue that transparency of methods and limitations, alongside proactive alignment of decisions with project objectives are critical for the successful application of eDNA metabarcoding in conservation and management decisions. We provide guidance for developing protocols that support species identification from eDNA metabarcoding sequences, and give recommendations on communication strategies for stakeholders and end users. To support these recommendations, we outline steps in the workflow that can impact species identification, with a discussion of the strengths and weaknesses at each stage. Ultimately, this guidance can improve the accuracy, reliability, and usability of eDNA and other metabarcoding and amplicon sequencing approaches to species identification while fostering trust and understanding among diverse end users.

This 37-y record (1989–2025) of field experiments tested seasonal and annual variation in predation on juvenile blue crabs ( Callinectes sapidus ) in a representative mesohaline site of Chesapeake Bay, USA, where the species is a dominant epibenthic predator and major fishery. We used replicated sets of individually tethered crabs to provide a relative index of lethal and sublethal predation rates on intermolt individuals as a function of size and habitats. Cannibalism by large adult crabs accounted for >97% of predation of juvenile crabs; predation by fish was not observed; and mortality from physiological stress was rare (120 mm adults had no predation. Cannibalism rates on juveniles varied seasonally, peaking during summer when adult crabs were most active; no tethering predation occurred in cold months. Variation in adult crab abundance accounted for 51% of annual variation in predation on tethered juveniles. Cannibalism by adult blue crabs provides a density-dependent regulation of juveniles by adults, with juvenile survivorship dependent on shallow-water refuge habitats in the mesohaline zone of the estuary. The refuge habitat appears increasingly restricted both by predatory fish common in high and recently introduced in low salinities, and by shoreline hardening.

Biodiversity affords resilience to populations, species, and ecosystems in the face of environmental disturbances. As the Earth’s climate continues to change rapidly, it is imperative that we understand how biodiversity is affected. In the eastern United States, a natural break in tropical and temperate climates occurs in the Mid-Atlantic Bight due to the Gulf Stream Current, which carries warm waters along the eastern Continental Shelf of the United States from the Gulf of Mexico. However, the Gulf Stream is shifting towards the coast, and the surface is warming, which will likely cause this climate delineation, and subsequently animal distributions, to shift. To establish a baseline of biodiversity in this region, we deployed 9 stations longitudinally from the coast that all monitor for animals that are tagged with acoustic transmitters and 6 of which monitor for cetacean vocalizations. In addition, we collect environmental DNA at these stations on a quarterly basis and utilize high frequency radar, gliders, oceanographic models, and remote sensing to pair environmental variables to biological observations. Through the integration of these disparate data streams, we model migration phenology of multiple species, determine biodiversity hot spots, and uncover longitudinal variation in migratory pathways, thereby increasing our understanding of patterns and changes in biodiversity on multiple temporal and spatial scales. We will make these data and modeling results available on the Marine Biodiversity Observation Network Portal, Mid-Atlantic Regional Association Coastal Ocean Observing System Oceansmap, Atlantic Cooperative Telemetry Network, Ocean Biodiversity Information System, and National Oceanic and Atmospheric Administration National Centers for Environmental Information. We are developing education materials that will be distributed through the Smithsonian Institution’s Ocean Portal. Consistent monitoring in key regions like the U.S. Mid-Atlantic Bight using these diverse collection methods and public endpoints enables managers to minimize the impacts of climate change on biodiversity and build resilience, manage wild species sustainability, enhance biodiversity and sustainability in fisheries, share benefits from genetic resources and digital sequence information, integrate biodiversity in decision-making, and ensure that data and knowledge are available and accessible to guide biodiversity action, all of which are targets of the Kunming-Montreal Global Biodiversity Framework.

Acoustic telemetry is an increasingly common method for obtaining information on animal movement in aquatic environments and has great potential for supporting biodiversity monitoring frameworks. Acoustic telemetry systems involve transmitters that are attached to or are implanted in animals and receivers (hydrophones) that listen for and decode transmitted signals. The approach is particularly valuable for the many aquatic species that rarely or never spend time at the surface, where they can be tracked using satellite telemetry, or that are too small to carry satellite tags. Regional networks of acoustic telemetry researchers along coastlines and in rivers and estuaries have emerged to coordinate exchange of data and allow for tagged animals to be tracked from local to regional and continental scales. For example, the Atlantic Cooperative Telemetry Network (ACT) brings together >186 researchers from Maine to North Carolina, United States of America, who use acoustic telemetry as a key tool to study movements of >75 species. With >1,030 actively deployed receiver stations in the ACT Network and many more in neighboring networks, tagged animals can be tracked throughout the Atlantic coast of North America. Goals of individual studies conducted by network researchers are diverse, from documenting migration behaviors to understanding connectivity and phenology. ACT Network data are already used in a range of management and conservation applications including fisheries stock assessment, spatial management and planning, protected species monitoring and avoidance, beach safety programs, and fish passage assessment. However, there remains a critical need to develop standardized workflows to aggregate and convert movement data derived from acoustic telemetry into Essential Biodiversity Variables. Additional effort is needed to develop metrics that integrate acoustic telemetry data with other types of movement data. Nevertheless, the community of acoustic telemetry users has made substantial progress on data standardization and development of pipelines that can support the integration of acoustic telemetry data into EBVs.

The Atlantic Cooperative Telemetry (ACT) Network is one of eight regional networks in the US, representing researchers from Maine to North Carolina, USA, who track animals using acoustic telemetry. We assessed ACT as an example of how these networks can facilitate data exchange between researchers and inform management and conservation. We characterized content of ACT Network publications and projects using topic modeling and identified applications of acoustic telemetry data by contacting network members. Case studies grouped into several types of management and conservation decisions, three of which were reflected in popular paper and project topics (stock assessment, spatial management, and protected species monitoring and avoidance), plus two additional types (beach safety and fish passage assessment). Case studies demonstrated the importance of building relationships among researchers and managers, co-development of research, and making data products publicly available. Future success applying acoustic telemetry in management and conservation will likely depend on regional network participation, stable investment in receiver arrays, network coordination, data management, FAIR data principles, and strategic tag deployments.