Florida Sea Grant

ABSTRACT Objective Hogfish Lachnolaimus maximus, popular as a sport and food fish, have historically experienced overfishing throughout portions of their range, prompting management agencies to seek interventions to support disrupted populations. Aquaculture and subsequent stock enhancement potentially support intervention efforts, but evaluations of stocking success first require effective assessment tools (e.g., mark–recapture experiments). Various marking methods are available, but their utility may be limited by cost, labor, and species-specific methodologies. Calcein is an efficient, nonlethal, fluorescent chemical marker that potentially addresses problems commonly associated with more traditional marking methods. Standard calcein marking practices use osmotic induction; however, protocols, marking efficacy, and retention may be specific to species and environment. Methods First, a trial was completed to determine the most efficient salinity pretreatment for the osmotic induction of calcein. A second trial determined the calcein concentration that resulted in the brightest mark. Two subsequent trials examined the effects of time and lighting scenarios on calcein mark retention. Results Osmotic induction experiments showed positive correlations between mark brightness, calcein concentration, and salinity pretreatment. Retention experiments suggested vulnerability of marks, with rapid degradation of mark brightness over 3 to 8 weeks. Conclusions These results, along with calcein’s current regulatory status, cast doubt on the viability of calcein as an external mark for stock assessment studies in Hogfish, although more research is needed to assess its viability in natural settings. The results from this research will help guide future aquaculture and stock enhancement efforts for Hogfish and add to the growing body of literature for this valuable marine species.

Abstract Understanding restoration trajectories and their sensitivity to climate is critical for designing effective adaptation strategies for restoration projects. Tidal marsh restoration often involves initial bare earth conditions that may be stressful to colonizing plants, especially on high elevation marsh platforms built to be resilient to sea‐level rise. Under these circumstances, stressors such as soil salinity may increase over time, but can be mitigated by strong rainfall. At Hester Marsh, a large tidal marsh restoration site in Elkhorn Slough, California, we evaluated passive restoration success, tracking colonization by plants whose seeds arrived naturally on tides, and active restoration success, monitoring greenhouse‐grown transplants. Our investigation revealed nonlinear restoration trajectories with high climate sensitivity, at the scale of the entire landscape and of individual plants. We found strong effects of drought on marsh restoration success indicators. Plant colonization rate decreased dramatically over time in the first area to be completed, which experienced more drought conditions following construction. In contrast, it declined more slowly in the second area, which experienced more rainy years following construction. Both passive and active restoration showed strong differences across these areas and across dry and rainy years. Facilitation can sometimes improve conditions for later‐arriving plants, but we found higher mortality of seedlings under existing vegetation than in bare areas. Thus, plant colonization may slow over time both due to increasing abiotic stress and through competition by early colonizers. Our findings lead to recommendations for climate adaptation strategies for tidal marsh restoration. Since we found that the first year following construction appeared to have the least stressful conditions, we recommend managers invest especially heavily in supporting plant colonization during this early window of opportunity. We also found plant size and species affected drought tolerance and recommend larger plant sizes and hardy species be incorporated into active tidal marsh restoration. Furthermore, we recommend planning for phased completion of restoration projects to generate a mosaic of areas with different trajectories and increase the probability that some areas will be completed during optimal climate conditions. We thus illustrate how an understanding of climate sensitivity of restoration trajectories can enhance restoration success.

In subtropical preserve ecosystems, natural factors combined with anthropogenic activities have led to significant seasonal changes, including distinct dry and rainy seasons. These changes can potentially impact soil health indicators, which are keystone properties that control ecosystem services across terrestrial landscapes. Few studies have evaluated the impact of seasonal changes on soil health within non-agronomic landscapes, such as preserves. As part of this study, we collected topsoil samples (0-15 cm) from twenty-three land cover types within a 109 km² preserve in central Florida during two different seasons (dry and wet) to advance the understanding of how soil health responds to seasonal changes and to explore the environmental factors controlling soil health within non-agronomic landscapes. Ten soil indicators were analyzed and incorporated into the total dataset (TDS). From the TDS, a minimum dataset was derived using Principal Component Analysis, which was then used to calculate the Soil Health Index (SHI) for soil health assessment. Our findings showed that changes in soil indicators, their relationships, and the SHI across seasons depend on land cover type. Based on soil health classification grades, soil health status either improved, declined, or remained constant between seasons, depending on land cover type. The regression analysis of eight selected environmental factors, such as soil profile moisture (SPM), surface soil wetness (SSW), precipitation (P), soil temperature (T), elevation (El), slope gradient (S), global horizontal irradiance (GHI) and surface albedo (ALB), showed that only slope gradient significantly explains variations in SHI during wet season, whereas other environmental factors do not show significant explanatory power for SHI variations in either dry or wet season. These findings highlight the dominant influence of slope gradient on soil health within non-agronomic landscapes, while indicating that other evaluated environmental factors may have limited relevance in this context. Furthermore, the non-significant findings among soil indicators across seasons may be attributed to the study's small sample size (i.e., three replications), a limitation stemming from constrained funding. This highlights the importance of future research incorporating larger sample size to validate the findings of this study.

Introduction: Hypertension (HTN) is a complex condition with significant heterogeneity in presentation and treatment response. Identifying distinct subphenotypes of HTN may improve our understanding of its underlying mechanisms and guide more precise treatment or public health initiatives. Methods: Using EHR data from the OneFlorida+ research consortium (2012-2021), we identified a cohort of adult Floridians with newly-diagnosed HTN (first diagnosis following 2 outpatient BPs ≥140/90 mmHg & no prior antiHTN treatment). We extracted demographic and clinical data from the diagnosis visit and ≤1 year prior. We used hierarchical clustering to identify distinct subphenotypes within the HTN population. Results: A total of 40,741 patients were included (mean ± SD age, 61 ± 18 y; 55% women). Six subphenotypes (S1-6) were identified (Figure). For example, S1 was characterized by older age and higher BMI and T2DM prevalence, while S2 included younger individuals with lower BMI and more women, and S3 had low prevalence of HTN-related comorbidity. Distinctions in SDOH factors were also observed: despite lower comorbidity burden, the youngest subphenotype (S2) had high SDOH burden and presented with HTN 8-15 y earlier than higher income subphenotypes (e.g., S4 & S5). Conclusions: Unsupervised learning identified 6 HTN subphenotypes varying in demographic, socioeconomic and risk profiles. Further investigation into biological mechanisms of these subphenotypes and their relationships to social factors may enhance our ability to deliver targeted interventions that consider social policy implications in addition to the traditional behavioral and physiological interventions.

Abstract Salt marshes remove terrestrially derived nutrients en route to coasts. While these systems play a critical role in improving water quality, we still have a limited understanding of the spatiotemporal variability of biogeochemically reactive solutes and processes within salt marshes. We implemented a high‐frequency sampling system to monitor sub‐hourly nitrate () concentrations in salt marsh porewater at Elkhorn Slough in central California, USA. We instrumented three marsh positions along an elevation gradient subjected to different amounts of tidal inundation, which we predicted would lead to varied biogeochemical characteristics and hydrological interactions. At each marsh position, we continuously monitored porewater concentrations at depths of 10, 30, and 50 cm and porewater levels measured at 70 cm depth over seven deployments of ~10 days each that spanned seasonal wet/dry periods common to Mediterranean climates. We quantified tidal event hysteresis between and water level to understand how concentrations and sources fluctuate across tidal cycles. In dry periods, the ‐porewater level relationship indicated that the source was likely estuarine surface water that flooded the transect during high tides and the salt marsh was a sink. In wet periods, the ‐porewater level relationship suggested the salt marsh was a source of . These findings suggest that tidal and seasonal hydrologic fluxes together control porewater dynamics and export and influence ecological processes in coastal environments.

Abstract The price of most food products is a function of attributes related to the product itself and signals associated with product features. Using a novel data source, online restaurant menus, this study examines the impact of various attributes on raw, half shell oyster prices in the United States. We find that oyster value is significantly affected by region, as well as the amount and type of information provided. West coast oysters, oysters sold in the Pacific region, and oysters sold on menus with additional information receive the highest price premiums. These findings suggest significant market segmentation exists within the United States.

Abstract Seafood is the food group with the highest share traded, and the U.S. is the world’s largest seafood importer, importing 79% of the seafood consumed. Hence, a study examining the impacts of the measures to contain COVID-19 on U.S. seafood imports will not only show how U.S. seafood availability has been affected, but will also give strong indications of how resiliently the global seafood markets have worked through the pandemic. We find that U.S. imports of seafood actually increased in 2020 and 2021, suggesting supply chains were able to adapt to potential disruptions. Moreover, for the 14 largest product forms imported to the U.S., there are no strong price movements. Given that there is a global market for most species groups, this adaption also suggests that the markets have worked quite well beyond the U.S. Hence, while there have undoubtedly been market shocks associated with the COVID-19 measures such as the reduction in demand from the restaurant sector and the increased sales in the retail sector, opportunities seem to balance out challenges, and the supply chains for seafood to the U.S. have been highly resilient.

The reliability and validity of the subjective component of the Dutch Objective Burden Inventory (DOBI) are unknown. The validity and reliability of the subjective component of the DOBI were examined in caregivers of individuals with heart failure, using the original 38- and a 24-item version. In an online cross-sectional investigation, confirmatory factor analysis was used to examine factorial validity. In examining convergent validity, corrected item-dimension correlations assessed item performance and associations between subjective subscale scores and the Bakas Caregiving Outcomes Scale. Cronbach's α examined internal consistency. The original 4-factor solution was retained and both the original and shorter versions of the subjective component of the DOBI supported adequate construct validity and internal consistency. Both the 38- and 24-item forms of the subjective DOBI supported construct validity and reliability. Further studies examining the usefulness of both versions are needed in carers of individuals with more severe HF.

Raymond Grizzle⇑ Research Professor, Department of Biological Sciences, Jackson Estuarine Laboratory, University of New Hampshire, 85 Adams Point Road, Durham, NH 03824. ray.grizzle{at}unh.edu.