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The Atlantic goliath grouper (Epinephelus itajara) is the largest grouper species in the Atlantic and exhibits high site fidelity and limited range of movement. By 1990, the goliath grouper population in US waters had declined approximately 95% relative to unfished levels, leading to a harvest ban in 1990. Since then, the south Florida population has grown but the magnitude of recovery remains unknown due to uncertainties about life history characteristics. However, despite these unknowns, the state of Florida approved a limited recreational harvest of goliath grouper. In 2021, fine-scale habitat use of three juvenile goliath grouper was investigated using acoustic telemetry and a positioning solver. All three individuals exhibited high site fidelity as well as a diel habitat use pattern, utilizing seagrass habitat during the night and mangrove habitat during the day. Fine-scale acoustic telemetry provides insight into not only habitat use, but broader habitat preferences as well. This study illustrates the need to consider deep seagrass-dominated channels lined with red mangroves when protecting juvenile goliath grouper populations within Florida Bay, especially as the population is opened to harvest.

 

Seagrass beds in Florida Bay are home to many ecologically and economically important species. Anthropogenic press perturbation via alterations in hydrology and pulse perturbations such as drought can lead to hypersalinity, hypoxia, and sulfide toxicity, ultimately causing seagrass die-offs. Florida Bay has undergone two large-scale seagrass die-offs, the first in the late 1980s and early 1990s and the second in 2015. Post-die-off events, samples were collected for stable isotope analysis. Using historical (1998–1999) and contemporary (2018) stable isotope data, we examine how food webs in Florida Bay have changed in response to seagrass die-off over time by measuring contributions of basal sources to energy usage and using trophic niche analysis to compare niche size and overlap. We examined three consumer species sampled in both time periods (Orthopristis chrysoptera, Lagodon rhomboides, and Eucinostomus gula) in our study. Seagrass production comprised the majority of source usage in both datasets. However, contemporary consumers had a mean increase of 18% seagrass usage and a mean decrease in epiphyte usage of 7%. The shift in trophic niche from epiphyte usage (green pathway) toward seagrass usage (brown pathway) may indicate that food web browning is occurring in Florida Bay. 

Natural and anthropogenic disturbances have led to rapid declines in the amount and quality of available habitat in many ecosystems. Many studies have focused on how habitat loss has affected the composition and configuration of habitats, but there have been fewer studies that investigate how this loss affects ecosystem function. We investigated how a large‐scale seagrass die‐off altered the distribution of energetic resources of three seagrass‐associated consumers with varied resource use patterns. Using long‐term benthic habitat monitoring data and resource use data from Bayesian stable isotope mixing models, we generated energetic resource landscapes (E‐scapes) annually between 2007 and 2019.E‐scapes link the resources being used by a consumer to the habitats that produce those resources to calculate a habitat resource index as a measurement of energetic quality of the landscape. Overall, our results revealed that following the die‐off there was a reduction in trophic function across all species in areas affected by the die‐off event, but the response was species‐specific and dependent on resource use and recovery patterns. This study highlights how habitat loss can lead to changes in ecosystem function. Incorporating changes in ecosystem function into models of habitat loss could improve understanding of how species will respond to future change.

 

Abstract Background Spawning migrations are a widespread phenomenon among fishes, often occurring in response to environmental conditions prompting movement into reproductive habitats (migratory cues). However, for many species, individual fish may choose not to migrate, and research suggests that conditions preceding the spawning season (migratory primers) may influence this decision. Few studies have provided empirical descriptions of these prior conditions, partly due to a lack of long-term data allowing for robust multi-year comparisons. To investigate how primers and cues interact to shape the spawning migrations of coastal fishes, we use acoustic telemetry data from Common Snook ( Centropomus undecimalis ) in Everglades National Park, Florida, USA. A contingent of Snook migrate between rivers and coastal spawning sites, varying annually in both the proportion of the population that migrates and the timing of migration within the spawning season. However, the specific environmental factors that serve as migratory primers and cues remain unknown. Methods We used eight years of acoustic telemetry data (2012–2019) from 173 tagged Common Snook to investigate how primers and cues influence migratory patterns at different temporal scales. We hypothesize that (1) interannual differences in hydrologic conditions preceding the spawning season contribute to the number of individuals migrating each year, and (2) specific environmental cues trigger the timing of migrations during the spawning season. We used GLMMs to model both the annual and seasonal migratory response in relation to flow characteristics (water level, rate of change in water level), other hydrologic/abiotic conditions (temperature, salinity), fish size, and phenological cues independent of riverine conditions (photoperiod, lunar cycle). Results We found that the extent of minimum marsh water level prior to migration and fish size influence the proportion of Snook migrating each year, and that high river water level and daily rates of change serve as primary cues triggering migration timing. Conclusion Our findings illustrate how spawning migrations are shaped by environmental factors acting at different temporal scales and emphasize the importance of long-term movement data in understanding these patterns. Research providing mechanistic descriptions of conditions that promote migration and reproduction can help inform management decisions aimed at conserving ecologically and economically important species. 

Fisheries provide countless benefits to human populations but face many threats ranging from climate change to overfishing. Despite these threats and an increase in fishing pressure globally, most stocks remain unassessed and data limited. An abundance of data‐limited assessment methods exists, but each has different data requirements, caveats, and limitations. Furthermore, developing informative model priors can be difficult when little is known about the stock, and uncertain model parameters could create misleading results about stock status. Our research illustrates an approach for rapidly creating robust initial assessments of unregulated and data‐limited fisheries without the need for additional data collection.

Our method uses stakeholder knowledge combined with a series of data‐limited tools to identify an appropriate stock assessment method, conduct an assessment, and examine how model uncertainty influences the results. Our approach was applied to the unregulated and data‐limited fishery for Crevalle JackCaranx hipposin Florida.

Results suggested a steady increase in exploitation and a decline in stock biomass over time, with the stock currently overfished and undergoing overfishing. These findings highlight a need for management action to prevent continued stock depletion.

Our approach can help to streamline the initial assessment and management process for unregulated and data‐limited stocks and serves as an additional tool for combating the many threats facing global fisheries.

 

Pink shrimp (Farfantepenaeus duorarum) are an economically important species in Biscayne Bay, FL, and support both food and bait commercial fisheries. Pink shrimp are also an important food resource for higher trophic level finfish species. This includes those fishes that support Florida’s iconic and highly valued recreational flats fisheries—which have experienced a severe decline in recent decades and may be impacted by the pink shrimp fisheries. Despite their economic and ecological importance, few studies have evaluated the long-term trends in Biscayne Bay’s pink shrimp fisheries. In this study, we evaluated over 30 years (1987–2020) of fisheries-dependent and economic data on the pink shrimp bait and food fisheries in Biscayne Bay with segmented regression to identify trends and potential breakpoints. We also evaluate trends in Biscayne Bay bonefish (Albula vulpes) over 25 years (1993–2018), based on recreational angler interview data, and assess potential interactions with the shrimp fisheries. We found that landings, value, effort, and participation (number of vessels and dealers) in both Biscayne Bay pink shrimp fisheries have exhibited declines from peaks in the late 1990s. No significant trends were detected in annual bonefish catch or catch per unit effort (catch/trip), but fishing effort declined over the time series. We did not find a significant relationship between annual bonefish catch per unit effort and commercial shrimp fishing landings or effort, suggesting that the pink shrimp fisheries are not a primary factor contributing to declines in the Biscayne Bay bonefish fishery. 

The recreational flats fishery (bonefish, tarpon, and permit) in South Florida is economically and culturally important and has declined recently for unknown reasons. Biscayne Bay is a shallow subtropical lagoon system with a flats fishery bordered by a large urban center. The Bay also supports commercial fisheries, including the pink shrimp bait and food fisheries. These two shrimp fisheries represent Biscayne Bay’s most valuable fisheries, but how these fisheries interact with the recreational flats fishery is relatively unknown. We conducted a literature review to identify the potential direct and indirect effects of the two shrimp fisheries on the recreational flats fishery in the Bay. Our review found that there are likely minimal impacts of the Biscayne Bay pink shrimp fisheries on the flats fishery in Biscayne Bay since (a) the species are not caught by shrimping gear, (b) the shrimp fishery removes less than 10% of the Bay’s shrimp population, and (c) damage to seagrass is minimal (but hardbottom is damaged). Yet, the potential for indirect prey removal cannot be ruled out and requires quantification with additional diet data, food web, and mass balance models.