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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.
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Movements of aquatic mesopredators within the Shark River estuary (FCE LTER), Everglades National Park, South Florida, USA, February 2012 - ongoing
In South Florida, the allocation of the limited freshwater supply is of constant debate. Stakeholder groups for freshwater include agriculture, South Florida populations, and the natural environment and the ecosystem services that they provide. One ecosystem service invaluable to South Florida is the provisioning of coastal recreational fisheries. This ecosystem service generates approximately 8 billion dollars in angler expenditures in Florida alone. However, the interplay between the provisioning of fisheries and the allocation and input of freshwater to coastal systems is largely unknown. One such way that recreationally important fishes could be impacted by changes in freshwater inputs to coastal systems is through the availability of food. Previous research has shown that seasonal rainfall patterns and freshwater management create spikes in prey availability for important recreational fishes such as Common Snook (Centropomus undecimalis) and Largemouth Bass (Micropterus salmoides). These prey pulses are restricted to the most inland reaches of the estuary. However, two important questions remain unanswered: 1) How far away do snook and bass move to take advantage of this prey subsidy? 2) Do these spikes in prey availability increase the reproductive output of snook? In order to answer these questions, we use acoustic telemetry to track the movements of key recreational fish species (Common Snook and Largemouth Bass) over multiple years (2012 – current) in the Shark River Estuary, Everglades National Park. Data provided by this study will be the first step in quantifying the importance of freshwater inflows to coastal fisheries. From a science perspective our research will provide valuable insight to how highly mobile species respond to pulses of prey across a patchy landscape, and how these temporary highly abundant resources will act to boost consumer populations. The value of pulsed resources to consumers have been identified as an important information gap in population ecology.
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- Award ID(s):
- 2025954
- PAR ID:
- 10643721
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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