- NSF-PAR ID:
- Date Published:
- Journal Name:
- Marine Ecology Progress Series
- Page Range / eLocation ID:
- 169 to 183
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Predicting the responses of animals to environmental changes is a fundamental goal of ecology and is necessary for conservation and management of species. While most studies focus on relatively gradual changes, extreme events may have lasting impacts on populations. Animals respond to major disturbances such as hurricanes by seeking shelter, migrating, or they may fail to respond appropriately. We assessed the effects of Hurricane Irma in 2017 on the behavior and survival of juvenile bull sharks (Carcharhinus leucas) within a nursery of the Florida coastal Everglades using long-term acoustic telemetry monitoring. Most of our tagged sharks (n = 14) attempted to leave the shallow waters of the Shark River Estuary before the hurricane strike, but individuals varied in the timing and success of their movements. Eight bull sharks left within hours or days before the hurricane, but three left more than a week in advance. Nine of 11 bull sharks (~ 82%) eventually returned to the array within weeks or months of the storm. Six of these returning individuals were detected in a different coastal array in nearshore waters ca. 80 km away from the mouth of the estuary during their absence. The remaining three bull sharks moved downstream relatively late (after the hurricane) and may have died. We used binomial generalized linear mixed models to estimate the probability of presence within the array as a function of several environmental variables. Departure from the array was predicted by declining barometric pressure, increasing rate of change in pressure, and potentially fluctuations in river stage. Juvenile bull sharks may weigh multiple environmental cues, perceived predation risk, their own physical size, and shifting prey resources when making decisions during and after hurricanes.more » « less
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.
The patchy nature of landscapes drives variation in the extent of ecological processes across space. This spatial ecology is critical to our understanding of organism-environmental interactions and conservation, restoration, and resource management efforts. In fisheries, incorporation of the spatial ecology of fishes remains limited, despite its importance to fishery assessment and management. This study quantified the effects of variation in headwater river stage, as an indicator of freshwater inflow, on the distribution and movement of a valuable recreational fishery species in Florida, common snook (Centropomus undecimalis). The hypothesis tested was that variation in river stage caused important habitat shifts and changes in the movement behavior of Snook. A combination of electrofishing and acoustic telemetry was used to quantify the distribution and movement patterns of snook in the upper Shark River Estuary, Everglades National Park. Negative relationships with river stage were found for all three variables measured: electrofishing catch per unit effort, the proportion of detections by upstream acoustic receivers, and movement rates. Snook were up to 5.8 times more abundant, were detected 2.3 times more frequently, and moved up to 4 times faster at lower river stages associated with seasonal drawdowns in water level. These findings show how seasonal drawdowns result in local aggregations of consumers, largely driven by improved foraging opportunities, and emphasize the importance of maintaining the natural variance in managed hydrological regimes. Results also highlight the importance of understanding the nature of flow-ecology relationships, especially given projected changes in freshwater availability with climate change.more » « less
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The effective management of invasive species requires detailed understanding of the invader’s life history. This information is essential for modeling population growth and predicting rates of expansion, quantifying ecological impacts and assessing the efficacy of removal and control strategies. Indo-Pacific lionfish (
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