Fredrick Joel Fodrie

Carry-over effects (COEs) are hypothesized to be important drivers of intraspecific fitness variation; however, difficulty in linking COEs across life-history stages make specific examples rare. Here, we examined whether use of alternative, putative nursery habitats could result in COEs apparent in later life-history dynamics of black sea bass ( Centropristis striata ). First, past nursery utilization of adult black sea bass was retroactively determined by matching geochemical signatures in the juvenile-stage-deposited portion of otoliths from those individuals to a multi-annual atlas of signatures from juvenile fish captured in estuarine versus nearshore coastal-ocean habitats. Second, the following potential COEs, resulting from the use of estuarine versus nearshore coastal-ocean nurseries, were assessed: (1) juvenile-through-sub adult growth rates; and (2) timing of female-to-male sexual transition. Analyses of juvenile otoliths from estuarine and coastal-ocean habitats sampled over 6 years indicated that these two putative nursery alternatives could be distinguished, with up to 93% success, based on geochemical signatures that were subsequently used to determine past nursery utilization of adults. Overall, 89% and 11% of 277 adults were linked to estuarine versus coastal-ocean nurseries, respectively. Although we did not find any statistically unambiguous growth COEs resulting from the use of these separate juvenile habitats, growth rates trended 1–4% higher for juveniles that occupied estuarine nurseries in each of the first five years based on otolith annuli widths. Additionally, we found that sex-at-age appeared to vary markedly based on the juvenile habitat origin of individuals. Fish that utilized estuarine nurseries transitioned from female to male approximately six months earlier (following 95% confidence intervals for 50% male maturity) than those associated with coastal-ocean nurseries (χ ² = 7.19, p = 0.027, df = 2). This result, while intriguing, should be evaluated by larger sample sizes in future efforts and across a wider sweep of the species’ range to encompass additional estuarine and coastal-ocean habitats to build geochemical atlases. Thus, this study provides preliminary evidence of COEs that expand nursery-role concepts to include impacts on post-juvenile life history characteristics (e.g., reproductive ecology). Though tentatively documented for a coastal fish here, these COE results are potentially relevant for a wide range of taxa with ontogenetic habitat migrations across life histories.

Facilitation of seagrasses by bivalves may enhance benthic-pelagic coupling, which can improve water quality, decrease epiphyte loading, and increase nutrient availability within sediments. Working across fine (1 m ² ) and landscape (400 m ² ) scales, we investigated the role of hard clams ( Mercenaria mercenaria ) in facilitating seagrass ( Zostera marina and Halodule wrightii ) in North Carolina, USA. At this southern range limit for eelgrass, local meadows experience seasonal die-back due to abiotic (heat) stress that may intensify with climate change. We tracked multiple eelgrass responses over 12-month periods in plots where hard clams were added versus not added and found four primary trends. (1) There was little evidence that the addition of bivalves affected the nutrient content of seagrass tissues, nutrient availability in sediments, or epiphytic loading. (2) Despite the absence of obvious biochemical signatures, increases in above-ground biomass (seagrass meadow specific) suggests a potential positive response to clam additions at fine scales. (3) While these responses did not translate to increases in eelgrass cover at the landscape-scale, eelgrass leaf growth (elongation) was ~ 33% greater in clam-addition plots compared to control plots in the landscape-scale study. (4) At both fine and landscape scales, estimates of eelgrass seed production were 20–40% greater in clam-addition plots. Elevated growth rates and seed production following increases in bivalve densities might confer added resilience for eelgrass meadows enduring seasonally intense abiotic stress. As some seagrass-associated bivalves experience significant harvest pressure, conservation or restoration initiatives could acknowledge bivalve-seagrass facilitation and incorporate dual-species enhancement as an ecosystem-based management approach.

The Atlantic sharpnose (Rhizoprionodon terraenovae), blacknose (Carcharhinus acronotus), blacktip (Carcharhinus limbatus), and bonnethead (Sphyrna tiburo) sharks are commonly encountered large mobile consumers found in the estuaries along the western North Atlantic coast. The bulk of the dietary data for these species has been coarsely recorded at a broad taxonomic level (e.g., “teleost fish”). Here, we used DNA metabarcoding of fecal DNA collected using non-lethal cloacal swabs to identify the species of prey contributing to the diets of these shark species and measure the degree of trophic overlap. Samples were collected from 24 Atlantic sharpnose, 33 blacknose, six blacktip, and 17 bonnethead sharks in the summer of 2020. Based on previous dietary research on these shark species, we targeted teleost fishes and crustaceans using two previously published primer sets. From the 80 sharks sampled off the coast of North Carolina, we identified 38 prey taxa, with 82% classified to the species level and all assigned to at least the genus and family levels. The most common prey taxa found in the diet of the bonnethead was Atlantic blue crab (Callinectes sapidus; 44.75%, based on percent of occurrence) followed by penaeid shrimp (Penaeus spp.; 24.41%), mantis shrimp (Squilla empusa; 20.34%), and spot (Leiostomus xanthurus; 4.75%). Atlantic sharpnose and blacknose sharks had the largest Levin’s niche overlap, with both species relying on the same two most frequently consumed prey taxa: penaeid shrimp (Atlantic sharpnose: 33.33%, percent of occurrence, and blacknose: 34.78%) and spot (Atlantic sharpnose: 32.70% and blacknose: 22.32%). Bonnetheads and blacktips had the least amount of overlap between all shark species, where blacktips primarily consumed menhaden (Brevoortia spp.; 58.62%) and penaeid shrimp (26.44%). Our findings highlight the value of DNA metabarcoding in refining our understanding of predator diets, moving beyond broad taxonomic classifications to identify species-level prey associations and trophic interactions. As coastal habitats undergo increasing alteration due to anthropogenic impacts, such information is crucial for fisheries management, helping to identify key prey dependencies and anticipate potential ecosystem shifts.

Context: Understanding how ecological patterns and processes are affected by spatial heterogeneity is a foundational goal of landscape ecology. Recent extensions of this field have explored how habitat-associated soundscapes could inform biodiversity assessments and conservation decisions. Objectives: The present study aims to expand understanding of spatial variation in estuarine soundscapes by evaluating its relationship with the surrounding habitat mosaics, nektonic community, and abiotic variables. Methods: We sampled 24 habitat mosaics, including seagrass beds, saltmarsh creeks, oyster reefs, and unvegetated mudflats, in Back and Core Sounds, North Carolina, USA, during six sampling periods from May to August 2019. Soundscape summaries, including sound pressure level (SPL) and species-specific calls, were paired with patch- and landscape-scale habitat, community, and abiotic metrics. Differences among the acoustic spectrum at each site were evaluated using the spectral dissimilarity index and visualized using multivariate analyses. Multi-model inference and variance partitioning were used to evaluate the proportion of soundscape variation explained by each ecological metric. Results: Landscape-scale habitat metrics were important explanatory variables for all soundscape metrics summarized. Specifically, multivariate analyses revealed four common soundscape types best differentiated by metrics of habitat size and shape at patch and landscape scales and the dominant sources of biological acoustic activity. Variation in SPL across the continuum of habitat heterogeneity sampled was typically explained by landscape-scale habitat metrics such as species richness, seagrass core area, and oyster reef perimeter. Species-specific call rates were explained by habitat and abiotic metrics and were unrelated to nektonic abundance and richness. Conclusions: Our results suggest that soundscape metrics could be useful for monitoring estuarine habitat mosaics and acoustic communities over space and time as well as indicating environmental relationships for some soniferous species, though soundscapes may not be an effective proxy for nekton assemblage structure. This study also highlights the value of integrating multiple remote sensing technologies to understand patterns between landscape structure, ecological dynamics, and estuarine soundscapes as well as demonstrates the application of deep learning frameworks for interpretation of soundscape patterns.

Diseases are ubiquitous in natural systems, with broad effects across populations, communities and ecosystems. However, the drivers of many diseases remain poorly understood, particularly in marine environments, inhibiting effective conservation and management measures. We examined biogeographical patterns of infection in the foundational seagrass Zostera marina by the parasitic protist Labyrinthula zosterae , the causative agent of seagrass wasting disease, across >20° of latitude in two ocean basins. We then identified and characterized relationships among wasting disease prevalence and a suite of host traits and environmental variables. Host characteristics and transmission dynamics explained most of the variance in prevalence across our survey, yet the particular host traits underlying these relationships varied between oceans, with host size and nitrogen content important in the Pacific and host size and density most important in the Atlantic. Temperature was also a key predictor of prevalence, particularly in the Pacific Ocean. The strength and shape of the relationships between prevalence and some predictors differed in our large-scale survey versus previous experimental and site-specific work. These results show that both host characteristics and environment influence host–parasite interactions, and that some such effects scale up predictably, whereas others appear to depend on regional or local context.

Aim: Biogenic structural complexity increases mobile animal richness and abundance at local, regional and global scales, yet animal taxa vary in their response to complexity. When these taxa also vary functionally, habitat structures favouring certain taxa may have consequences for ecosystem function. We characterised global patterns of epifaunal invertebrates in eelgrass (Zostera marina) beds that varied in structural and genetic composition.Location: North America, Europe and Asia.Time Period: 2014.Major Taxa Studied: Peracarid crustaceans and gastropod molluscs.Methods: We sampled epifaunal invertebrate communities in 49 eelgrass beds across 37° latitude in two ocean basins concurrently with measurements of eelgrass genetic diversity, structural complexity and other abiotic and biotic environmental variables. We examined how species richness, abundance and community composition varied with latitude and environmental predictors using a random forest approach. We also examined how functional trait composition varied along with community structure.Results: Total species richness decreased with latitude, but this was accompanied by a taxonomic shift in dominance from peracarid crustaceans to gastropods, which exhibited different sets of functional traits. Greater eelgrass genetic diversity was strongly correlated with both richness and abundance of peracarids, but less so for gastropods.Main Conclusions: Our results add to a growing body of literature that suggests genetic variation in plant traits influences their associated faunal assemblages via habitat structure. Because peracarids and gastropods exhibited distinct functional traits, our results suggest a tentative indirect link between broad‐scale variation in plant genetic diversity and ecosystem function.