Aquatic Research and Communication LLC

Homestead, FL, United States

Aquatic Research and Communication LLC

Homestead, FL, United States
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Rehage J.S.,Florida International University | Liston S.E.,Audubon Florida | Dunker K.J.,Alaska Department of Fish and Game | Loftus W.F.,Aquatic Research and Communication LLC
Wetlands | Year: 2014

Short-hydroperiod Everglades wetlands have been disproportionately affected by reductions in freshwater inflows, land conversion and biotic invasions. Severe hydroperiod reductions in these habitats, including the Rocky Glades, coupled with proximity to canals that act as sources of invasions, may limit their ability to support high levels of aquatic production. We examined whether karst solution holes function as dry-down refuges for fishes, providing a source of marsh colonists upon reflooding, by tracking fish abundance, nonnative composition, and survival in solution holes throughout the dry season. We paired field surveys with an in situ nonnative predation experiment that tested the effects of predation by the recent invader, African jewelfish (Hemichromis letourneuxi) on native fishes. Over the 3 years surveyed, a large number of the solution holes dried before the onset of the wet season, while those retaining water had low survivorship and were dominated by nonnatives. In the experiment, mortality of eastern mosquitofish (Gambusia holbrooki) in the presence of African jewelfish was greater than that associated with deteriorating water quality. Under current water management, findings suggest that solution holes are largely sinks for native fishes, given the high frequency of drydown, extensive period of fish residence, and predation by nonnative fishes. © Society of Wetland Scientists 2013.


Kline J.L.,South Florida Natural Resources Center | Loftus W.F.,Aquatic Research and Communication LLC | Kotun K.,South Florida Natural Resources Center | Trexler J.C.,Florida International University | And 3 more authors.
Wetlands | Year: 2014

Non-native fishes present a management challenge to maintaining Everglades National Park (ENP) in a natural state. We summarized data from long-term fish monitoring studies in ENP and reviewed the timing of introductions relative to water-management changes. Beginning in the early 1950s, management actions have added canals, altered wetland habitats by flooding and drainage, and changed inflows into ENP, particularly in the Taylor Slough/C-111 basin and Rocky Glades. The first nonnative fishes likely entered ENP by the late 1960s, but species numbers increased sharply in the early 1980s when new water-management actions were implemented. After 1999, eight non-native species and three native species, all previously recorded outside of Park boundaries, were found for the first time in ENP. Several of these incursions occurred following structural and operational changes that redirected water deliveries to wetlands open to the eastern boundary canals. Once established, control non-native fishes in Everglades wetlands is difficult; therefore, preventing introductions is key to their management. Integrating actions that minimize the spread of non-native species into protected natural areas into the adaptive management process for planning, development, and operation of watermanagement features may help to achieve the full suite of objectives for Everglades restoration. © US Government 2013.


Porter-Whitaker A.E.,Nova Southeastern University | Rehage J.S.,Florida International University | Liston S.E.,Audubon of Florida | Loftus W.F.,Aquatic Research and Communication LLC
Ecology of Freshwater Fish | Year: 2012

Non-native predators may have negative impacts on native communities, and these effects may be dependent on interactions among multiple non-native predators. Sequential invasions by predators can enhance risk for native prey. Prey have a limited ability to respond to multiple threats since appropriate responses may conflict, and interactions with recent invaders may be novel. We examined predator-prey interactions among two non-native predators, a recent invader, the African jewelfish, and the longer-established Mayan cichlid, and a native Florida Everglades prey assemblage. Using field enclosures and laboratory aquaria, we compared predatory effects and antipredator responses across five prey taxa. Total predation rates were higher for Mayan cichlids, which also targeted more prey types. The cichlid invaders had similar microhabitat use, but varied in foraging styles, with African jewelfish being more active. The three prey species that experienced predation were those that overlapped in habitat use with predators. Flagfish were consumed by both predators, while riverine grass shrimp and bluefin killifish were eaten only by Mayan cichlids. In mixed predator treatments, we saw no evidence of emergent effects, since interactions between the two cichlid predators were low. Prey responded to predator threats by altering activity but not vertical distribution. Results suggest that prey vulnerability is affected by activity and habitat domain overlap with predators and may be lower to newly invading predators, perhaps due to novelty in the interaction. © 2012 John Wiley & Sons A/S.


Schofield P.J.,U.S. Geological Survey | Loftus W.F.,Aquatic Research and Communication LLC
Reviews in Fish Biology and Fisheries | Year: 2014

Non-native fishes have been known from freshwater ecosystems of Florida since the 1950s, and dozens of species have established self-sustaining populations. Nonetheless, no synthesis of data collected on those species in Florida has been published until now. We searched the literature for peer-reviewed publications reporting original data for 42 species of non-native fishes in Florida that are currently established, were established in the past, or are sustained by human intervention. Since the 1950s, the number of non-native fish species increased steadily at a rate of roughly six new species per decade. Studies documented (in decreasing abundance): geographic location/range expansion, life- and natural-history characteristics (e.g., diet, habitat use), ecophysiology, community composition, population structure, behaviour, aquatic-plant management, and fisheries/aquaculture. Although there is a great deal of taxonomic uncertainty and confusion associated with many taxa, very few studies focused on clarifying taxonomic ambiguities of non-native fishes in the State. Most studies were descriptive; only 15 % were manipulative. Risk assessments, population-control studies and evaluations of effects of non-native fishes were rare topics for research, although they are highly valued by natural-resource managers. Though some authors equated lack of data with lack of effects, research is needed to confirm or deny conclusions. Much more is known regarding the effects of lionfish (Pterois spp.) on native fauna, despite its much shorter establishment time. Natural-resource managers need biological and ecological information to make policy decisions regarding non-native fishes. Given the near-absence of empirical data on effects of Florida non-native fishes, and the lengthy time-frames usually needed to collect such information, we provide suggestions for data collection in a manner that may be useful in the evaluation and prediction of non-native fish effects. © 2014, Springer International Publishing Switzerland (outside the USA).


Goss C.W.,Florida International University | Goss C.W.,Ohio State University | Loftus W.F.,Aquatic Research and Communication LLC | Trexler J.C.,Florida International University
Wetlands | Year: 2014

We hypothesized that fishes in short-hydroperiod wetlands display pulses in activity tied to seasonal flooding and drying, with relatively low activity during intervening periods. To evaluate this hypothesis, sampling devices that funnel fish into traps (drift fences) were used to investigate fish movement across the Everglades, U.S.A. Samples were collected at six sites in the Rocky Glades, a seasonally flooded karstic habitat located on the southeastern edge of the Everglades. Four species that display distinct recovery patterns following drought in long-hydroperiod wetlands were studied: eastern mosquitofish (Gambusia holbrooki) and flagfish (Jordanella floridae) (rapid recovery); and bluefin killifish (Lucania goodei) and least killifish (Heterandria formosa) (slow recovery). Consistent with our hypothesized conceptual model, fishes increased movement soon after flooding (immigration period) and just before drying (emigration period), but decreased activity in the intervening foraging period. We also found that eastern mosquitofish and flagfish arrived earlier and showed stronger responses to hydrological variation than either least killifish or bluefin killifish. We concluded that these fishes actively colonize and escape ephemeral wetlands in response to flooding and drying, and display species-specific differences related to flooding and drying that reflect differences in dispersal ability. These results have important implications for Everglades fish metacommunity dynamics. © Society of Wetland Scientists 2013.


Schofield P.J.,U.S. Geological Survey | Slone D.H.,U.S. Geological Survey | Gregoire D.R.,U.S. Geological Survey | Loftus W.F.,Aquatic Research and Communication LLC
Hydrobiologia | Year: 2014

In an 8-month mesocosm experiment, we examined how a simulated Everglades aquatic community of small native fishes, snails, and shrimp changed with the addition of either a native predator (dollar sunfish Lepomis marginatus) or a non-native predator (African jewelfish Hemichromis letourneuxi) compared to a no-predator control. Two snail species (Planorbella duryi, Physella cubensis) and the shrimp (Palaemonetes paludosus) displayed the strongest predator-treatment effects, with significantly lower biomasses in tanks with Hemichromis. One small native fish (Heterandria formosa) was significantly less abundant in Hemichromis tanks, but there were no significant treatment effects for Gambusia holbrooki, Jordanella floridae, or Pomacea paludosa (applesnail). Overall, there were few treatment differences between native predator and no-predator control tanks. The results suggest that the potential of Hemichromis to affect basal food-web species that link primary producers with higher-level consumers in the aquatic food web, with unknown consequences for Florida waters. © 2013 Springer Science+Business Media Dordrecht (outside the USA).


Schofield P.J.,U.S. Geological Survey | Loftus W.F.,U.S. Geological Survey | Loftus W.F.,Aquatic Research and Communication LLC | Kobza R.M.,South Florida Water Management District | And 2 more authors.
Biological Invasions | Year: 2010

The cold tolerance of two non-native cichlids (Hemichromis letourneuxi and Cichlasoma urophthalmus) that are established in south Florida was tested in the field and laboratory. In the laboratory, fishes were acclimated to two temperatures (24 and 28°C), and three salinities (0, 10, and 35 ppt). Two endpoints were identified: loss of equilibrium (11.5-13.7°C for C. urophthalmus; 10.8-12.5°C for H. letourneuxi), and death (9.5-11.1°C for C. urophthalmus; 9.1-13.3°C for H. letourneuxi). In the field, fishes were caged in several aquatic habitats during two winter cold snaps. Temperatures were lowest (4.0°C) in the shallow marsh, where no fish survived, and warmest in canals and solution-holes. Canals and ditches as shallow as 50 cm provided thermal refuges for these tropical fishes. Because of the effect on survival of different habitat types, simple predictions of ultimate geographic expansion by non-native fishes using latitude and thermal isoclines are insufficient for freshwater fishes. © 2009 US Government.


Zokan M.,University of Georgia | Ellis G.,University of South Florida | Clem S.E.,Audubon Florida | Lorenz J.,Everglades Science Center | Loftus W.F.,Aquatic Research and Communication LLC
Southeastern Naturalist | Year: 2015

The Big Cypress Swamp (BCS) is a large freshwater wetland system and drainage basin (640,000 ha) in southwest Florida and an important component of the Greater Everglades ecosystem. Despite its size and relationship to the Ever glades, the fish fauna of BCS has received little study. Documentation of its fish fauna is important to better understand this dynamic natural system and to monitor changes to the fish community, including the spread of non-indigenous species. To that end, we surveyed the ichthyofauna of freshwater habitats in Big Cypress National Preserve (BCNP), the largest and most intact wetland area (295,000 ha) remaining in BCS. Between October 2002 and May 2004, we recorded 63 fish species from freshwater habitats in BCNP, including 9 non-indigenous species. Species richness was greatest in permanent freshwater habitats and lowest in shallow temporary wetlands and seasonally fresh coastal marshes. The most speciose families were the native Centrarchidae (8 spp.) and the non-native Cichlidae (6 spp.), whereas the most abundant and widely distributed species were members of Cyprinodontidae, Fundulidae, and Poecilidae. Similar to other coastal drainages of southern Florida, BCNP has a relatively high occurrence of euryhaline species (28 spp.). © 2015, BioOne. All rights reserved.


McCarthy L.C.,Nova Southeastern University | McCarthy L.C.,East Carolina University | Loftus W.F.,Aquatic Research and Communication LLC | Rehage J.S.,Florida International University
Bulletin of Marine Science | Year: 2012

Variation in physical gradients and production along estuaries can alter species compositions. Spatiotemporal variation in abundance and distribution of palaemonid shrimp species was investigated in relation to seasonal freshwater inputs and salinity in the Shark River Estuary, Everglades National Park, Florida, uSA. using trapping techniques, multiple sites were sampled repeatedly extending from the headwaters to the Gulf of Mexico. Stable isotope analyses were also performed on a subset of samples. Five palaemonid species occurred in the samples: Palaemonetes paludosus (Gibbes, 1850), Palaemonetes pugio (Holthuis, 1949), Palaemonetes intermedius (Holthuis, 1949), Palaemon floridanus (chace, 1942), and Leander paulensis (Ortmann, 1897). Overall, shrimp catches in traps doubled in the dry season. catches in the upper estuary were dominated by P. paludosus, particularly in the wet season, while catch per unit effort at the most downstream and highest salinity sites were dominated by P. floridanus. At mid-estuary, several species co-occurred. δ15N analyses revealed that most species filled similar roles in the community, with the exception of P. paludosus, which shifted from enrichment in the dry season to depletion in the wet season as it expanded downstream in the estuary. Palaemonid δ13C values varied between sites and seasons, with shrimp in upstream sites being more depleted. These data suggest that changes in salinity regimes resulting from Everglades restoration efforts may result in species replacement, with potential implications for trophic dynamics. © 2012 Rosenstiel School of Marine and Atmospheric Science of the University of Miami.


Stauffer Jr. J.R.,Pennsylvania State University | Loftus W.F.,Aquatic Research and Communication LLC
Copeia | Year: 2010

Bagrus meridionalis (Bagridae; locally called Kampango) is a large substrate-spawning catfish endemic to Lake Mala'i that exhibits bi-parental care and spawns primarily in the wet season from January to March. The female feeds her young trophic (unfertilized) eggs; the male orally collects offsite benthic organisms, which he brings back to feed the brood. While doing underwater videography in the lake, we observed evidence for brood parasitism of four Kampango nests by the most common clariid catfish in Lake Mala'i, the endemic Bathyclarias nyasensis (locally called Bombe). Parasitized Kampango nests held Bombe young almost exclusively, and these were protected by Kampango adults until they exceeded 100 mm SL. We found that female and male Kampango fed the Bombe juveniles with trophic eggs and macroinvertebrates, respectively, as they do their own young. These observations represent a sophisticated example of cuckoo behavior in fishes. © 2010 by the American Society of Ichthyologists and Herpetologists.

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