Extreme climate events such as hurricanes can influence the movement and distribution of fish and other aquatic vertebrates. However, our understanding of the scale of movement responses and how they vary across taxa and ecosystems remains incomplete. In this study, we used acoustic telemetry data to investigate the movement patterns of common snook (Centropomus undecimalis) in the Florida Coastal Everglades during Hurricane Irma, which made landfall on the southwest Florida coast as a Category 3 storm on 10 September 2017 after passing in close proximity to our study site. We hypothesized that the hurricane resulted in shifts in distribution and that these movements may have been driven by environmental cues stemming from changes in barometric pressure associated with hurricane conditions, fluctuations in water levels (stage) characterizing altered riverine conditions, or a combination of both hurricane and riverine drivers. The data revealed large-scale movements of common snook in the time period surrounding hurricane passage, with 73% of fish detected moving from the upper river into downriver habitats, and some individuals potentially exiting the river. Furthermore, regression model selection indicated that these movements were correlated to both hurricane and riverine conditions, showing increased common snook movement at higher river stage and lower barometric pressure, and stage explaining a larger proportion of model deviance. Animal movement has widespread and diverse ecological implications, and by better understanding the factors that drive movement, we may anticipate how future extreme climate events could affect fish populations in impact-prone regions.
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Untangling Flow-Ecology Relationships: Effects of Seasonal Stage Variation on Common Snook Aggregation and Movement Rates in the Everglades
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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- Award ID(s):
- 2025954
- NSF-PAR ID:
- 10318506
- Date Published:
- Journal Name:
- Estuaries and Coasts
- ISSN:
- 1559-2723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Understanding large‐scale migratory behaviours, local movement patterns and population connectivity are critical to determining the natural processes and anthropogenic stressors that influence population dynamics and for developing effective conservation plans. Atlantic tarpon occur over a broad geographic range in the Atlantic Ocean where they support valuable subsistence, commercial and recreational fisheries. From 2001 through 2018, we deployed 292 satellite telemetry tags on Atlantic tarpon in coastal waters off three continents to document: (a) seasonal migrations and regional population connectivity; (b) freshwater and estuarine habitat utilization; (c) spawning locations; and (d) shark predation across the south‐eastern United States, Gulf of Mexico and northern Caribbean Sea. These results showed that some mature tarpon make long seasonal migrations over thousands of kilometres crossing state and national jurisdictional borders. Others showed more local movements and habitat use. The tag data also revealed potential spawning locations consistent with those inferred in other studies from observations of early life stage tarpon leptocephalus larvae. Our analyses indicated that shark predation mortality on released tarpon is higher than previously estimated, especially at ocean passes, river mouths and inlets to bays. To date, there has been no formal stock assessment of Atlantic tarpon, and regional fishery management plans do not exist. Our findings will provide critical input to these important efforts and assist the multinational community in the development of a stock‐wide management information system to support informed decision‐making for sustaining Atlantic tarpon fisheries.
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Otolith microchemistry was useful for characterizing migratory histories of individuals, but there was no clear evidence that fish captured in different river zones used different types of natal habitats. Based on lifetime Sr:Ca in otoliths, a diverse array of movement patterns was evident in the Usumacinta system, with 97% of common snook showing evidence of freshwater habitat use.
Prevalent use of riverine habitats by common snook far from the coast reinforces the need to preserve connectivity in the Usumacinta River and other undammed systems supporting migratory species. The natural flow regime and lack of barriers allow for longitudinal and lateral connectivity in this system, providing pathways for migratory species to move extensively and have access to an array of habitats, including productive floodplain lagoons.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s12237-022-01065-x
