Florida Panhandle Research Articles

Benefits of Managing the Capacity of Special Needs Shelters with Cross-County Collaboration

A significant task of planners involved in emergency disaster management is planning for the optimal assignment of people to emergency shelters. This complex task depends on the available infrastructure and roadway characteristics and can take on additional complexity when older populations are considered because their health conditions may deteriorate during a disaster. Older people may also require special assistance even though they are not listed in the registries of people with special needs. This paper specifically focuses on the assignment of older populations to shelters. The paper presents a spatial optimization methodology based on data from a geographic information system. The focus is on the segment of the population 85 years old and older and on the use of potential benefits of cross-county collaboration in special needs shelter (SpNS) management. Such collaboration can help in using additional shelter capacity between neighboring counties ( a) to overcome the lack of capacity in a county and ( b) to assign the demand to a close shelter across county borders. The methodology was applied to a case study of five counties in the Florida Panhandle. Because the SpNS demand for the 85+ age group was not known exactly, a sensitivity analysis was conducted for different demand levels. From an emergency management perspective, this type of cross-county utilization can provide a means to use existing regular shelters in multiple counties to serve the 85+ population.

Spatiotemporal variability of meteorological droughts in southeastern USA

Droughts in the southeast USA have been linked to economic losses and intractable water conflicts. The region has witnessed several severe droughts events during the period from 1901 to 2005. In this study, spatiotemporal variability in meteorological drought characteristics in the southeast were analyzed using two different datasets by the means of standard precipitation index and standard precipitation evapotranspiration index for the period 1901–2005 for agricultural and non-agricultural seasons. The study periods were divided into three epochs 1901–1935, 1936–1970, and 1971–2005 and drought characteristics, in terms of severity, frequency, number, and trends were analyzed. Additionally, areal extent, drought severities and return periods associated with three severe drought years 1904, 1954, and 2000 were analyzed. Except for the state of Florida, results indicate decrease in drought severity during the recent epoch of 1970–2005 in the study domain. Trend analysis confirms that the study domain has become wetter over the last 105 years. Wetting trends were more prominent in the agricultural season. Additionally, droughts seem to have migrated from the western part of the study area encompassing the states of Alabama, Tennessee, Louisiana, and Mississippi to the Florida panhandle region during the recent epoch. Droughts exhibited higher spatiotemporal variability during the agricultural season compared to the non-agricultural seasons. Results also showed that early to mid-1950s experienced some of the most severe droughts in the study domain. Some of the drought events, such as the drought of 1954 and 2000, have been equivalent to a 100-year drought event in the southeast. The results from this study form the benchmark for studying the impacts of future climate change projections on meteorological droughts in the southeast.

Assessing genetic diversity for the USA endemic carnivorous plant Pinguicula ionantha R.K. Godfrey (Lentibulariaceae)

Understanding patterns of genetic diversity and population structure for rare, narrowly endemic plant species, such as Pinguicula ionantha (Godfrey’s butterwort; Lentibulariaceae), informs conservation goals and can directly affect management decisions. Pinguicula ionantha is a federally listed species endemic to the Florida Panhandle in the southeastern USA. The main goal of our study was to assess patterns of genetic diversity and structure in 17 P. ionantha populations, and to determine if diversity is associated with geographic location or population characteristics. We scored 240 individuals at a total of 899 AFLP markers (893 polymorphic markers). We found no relationship between the estimated population size with either of two measures of diversity (proportion of loci polymorphic, P = 0.37; Nei’s gene diversity, P = 0.50). We also found low levels of population genetic structure; there was no clear relationship of genetic isolation by distance (P = 0.23) and only a small (but significant) proportion of genetic variation was partitioned amongst regions (2.4 %, P = 0.02) or populations (20.8 %, P < 0.001). STRUCTURE analysis found that the model with two inferred clusters (K = 2) best described the AFLP data; the dominant cluster at each site corresponded to the results from PCoA and Nei’s genetic distance analyses. The observed patterns of genetic diversity suggest that although P. ionantha populations are isolated spatially by distance and both natural and anthropogenic barriers, some gene flow occurs among them or isolation has been too recent to leave a genetic signature. The relatively low level of genetic diversity associated with this species is a concern as it may impair fitness and evolutionary capability in a changing environment. The results of this study provide the foundation for the development of management practices that will assist in the protection of this rare carnivorous plant.

A New Species ofCatocala(Lepidoptera: Noctuidae) from the Gulf Coast of the Florida Panhandle

A new species of underwing moth, Catocala slotteni sp. nov., is described from three specimens from the Gulf Coast of the Florida Panhandle, USA. Corresponding characters from wing pattern, male genitalia and the 5′ region of Cytochrome Oxidase Subunit I mitochondrial DNA separate C. slotteni from phenotypically similar species in the genus.

Conservation implications of small population size and habitat fragmentation in an endangered lupine

Conservation measures to preserve critically endangered species aim to maintain healthy and self-sustaining populations and often involve reintroductions. Effective introductions must take into account the genetic structure and diversity remaining in the species to inform choices of germplasm for introduction strategies. Lupinus aridorum (McFarlin ex Beckner; Fabaceae) is an endangered plant found on two disjunct ridge systems in central Florida. All plants are found in areas that are favored for human development and agriculture. Few options exist for introduction locations, so the most informed strategies must be used to preserve this species. We used ten microsatellite loci, developed for this species, to determine genetic diversity and genetic differentiation among populations, and to compare L. aridorum with two closely related congeners. Our results show a low level of diversity remaining in the species in comparison with a more abundant congener and similar levels of variability among each L. aridorum population. At least three L. aridorum populations exhibit a genetic signal of partial selfing. Hybridization with a closely-related congener was not apparent; however, additional crossing trials are needed to fully assess the possibility of hybridization. Although some sources list the taxonomy of L. aridorum as a variety of a Florida panhandle species, L. westianus (Small), the genetic differences revealed by our data support listing these two species as separate entities. Our findings can be used to guide sampling strategies for ex situ conservation such as providing a mixture of source populations to improve the probability of successful introductions.

West Florida shelf upwelling: Origins and pathways

AbstractOften described as oligotrophic, the west Florida continental shelf supports abundant fisheries, experiences blooms of the harmful alga, Karenia brevis, and exhibits subsurface chlorophyll maxima evident in shipboard and glider surveys. Renewal of inorganic nutrients by the upwelling of deeper ocean water onto the shelf may account for this, but what are the origins and pathways by which such new water may broach the shelf break and advance toward the shoreline? We address these questions via numerical model simulations of pseudo‐Lagrangian, isopycnic water parcel trajectories. Focus is on 2010, when the west Florida shelf was subjected to an anomalously protracted period of upwelling caused by Gulf of Mexico Loop Current interactions with the shelf slope. Origins and pathways are determined by integrating trajectories over successive 45 day intervals, beginning from different locations along the shelf break and at various locations and depths along the shelf slope. Waters upwelling across the shelf break are found to originate from relatively shallow depths along the shelf slope. Even for the anomalous 2010 year, much of this upwelling occurs from about 150 m and above, although waters may broach the shelf break from 300 m depth, particularly in the Florida Panhandle. Such interannual renewal of west Florida shelf waters appears to have profound effects on west Florida shelf ecology.

Release and distribution of Lilioceris cheni (Coleoptera: Chrysomelidae), a biological control agent of air potato (Dioscorea bulbifera: Dioscoreaceae), in Florida

ABSTRACTFrom 2012 to 2015, 429,668 Lilioceris cheni Gressit and Kimoto (Coleoptera: Chrysomelidae) were released in Florida for biological control of air potato Dioscorea bulbifera L. (Dioscoreaceae). In the fall of 2015, a state-wide survey was conducted at 113 randomly selected air potato infestations in order to determine the spatial distribution of L. cheni. Damage due to L. cheni was found at 86% of locations and was low in the Florida panhandle where air potato was relatively uncommon and fewer beetles had been released, and in far south Florida, despite high numbers of beetle releases. On average, beetles travelled 9.5 km from the nearest release site to survey sites from the date of release to the time of the survey, with a maximum distance of nearly 67 km. The rate of spread was estimated at 8.2 km/year under the assumption that beetles present at survey sites migrated or were moved from the nearest release site. Air potato vines produced fewer aerial tubers, the vegetative propagule of air potato, as foliar damage due to L. cheni increased. The results suggest that future research efforts should focus on determining the biotic and abiotic factors that may be limiting establishment in some areas of Florida.

Data and numerical analysis of astronomic tides, wind‐waves, and hurricane storm surge along the northern Gulf of Mexico

AbstractThe northern Gulf of Mexico (NGOM) is a unique geophysical setting for complex tropical storm‐induced hydrodynamic processes that occur across a variety of spatial and temporal scales. Each hurricane includes its own distinctive characteristics and can cause unique and devastating storm surge when it strikes within the intricate geometric setting of the NGOM. While a number of studies have explored hurricane storm surge in the NGOM, few have attempted to describe storm surge and coastal inundation using observed data in conjunction with a single large‐domain high‐resolution numerical model. To better understand the oceanic and nearshore response to these tropical cyclones, we provide a detailed assessment, based on field measurements and numerical simulation, of the evolution of wind waves, water levels, and currents for Hurricanes Ivan (2004), Dennis (2005), Katrina (2005), and Isaac (2012), with focus on Mississippi, Alabama, and the Florida Panhandle coasts. The developed NGOM3 computational model describes the hydraulic connectivity among the various inlet and bay systems, Gulf Intracoastal Waterway, coastal rivers and adjacent marsh, and built infrastructure along the coastal floodplain. The outcome is a better understanding of the storm surge generating mechanisms and interactions among hurricane characteristics and the NGOM's geophysical configuration. The numerical analysis and observed data explain the ∼2 m/s hurricane‐induced geostrophic currents across the continental shelf, a 6 m/s outflow current during Ivan, the hurricane‐induced coastal Kelvin wave along the shelf, and for the first time a wealth of measured data and a detailed numerical simulation was performed and was presented for Isaac.

A Synthesis of Stream Restoration Efforts in Florida (USA)

Studies summarizing stream restoration projects in the US are outdated and omit the majority of restoration projects in Florida. To address this gap, we compiled stream restoration data from diverse sources to create a Florida Stream Restoration Database (FSRD, available at http://www.watershedecology.org/databases.html) containing information on project type, location, completion date, and costs. The FSRD contains 178 projects categorized by restoration type, including riparian management (23%), stream reclamation (19%), flow modification (13%), bank stabilization (12%), channel reconfiguration (11%), in-stream habitat improvements (11%), floodplain reconnection (6%), invasive species removal (4%), and dam removal (1%). Projects were spatially clustered into three geographic regions, providing insight on the diversity of initiatives, needs, and funding sources of land management agencies and private landowners that motivated restoration efforts. Projects in the Florida panhandle emphasized in-stream habitat restoration, while peninsular projects were dominated by flow modification, and projects in the west central region focused on stream reclamation to mitigate surface mining practices and water quality and habitat improvements in tidal streams. Results suggest that Florida is spending much more on stream restoration than previously documented. Between 1979 and 2015, the mean and median stream restoration project costs in Florida were $15.4 million and $180 000, respectively, indicating a strongly skewed distribution because of the large Kissimmee River restoration project in central Florida. This work highlights the need for, and utility of, statewide and national restoration databases to improve restoration tracking. This need will become increasingly critical as more stringent water quality and habitat mitigation rules are implemented across the country. Copyright © 2016 John Wiley & Sons, Ltd.

Novel Infection Site and Ecology of Cryptic Didymocystis sp. (Trematoda) in the Fish Scomberomorus maculatus.

An undescribed, cryptic species of Didymocystis, as determined from sequences of 2 ribosomal genes and superficially similar to Didymocystis scomberomori ( MacCallum and MacCallum, 1916 ), infected the skin of the Spanish mackerel, Scomberomorus maculatus , in the north-central Gulf of Mexico (GOM). An analysis of 558 fish from 2011 to 2013 from Louisiana, Mississippi, Alabama, and the Florida panhandle showed the prevalence of the trematode varied both spatially and temporally but not with sex of the fish host. Month, year, and geographic location were identified by a negative binomial generalized linear model as indicators of the abundance and intensity of infection. Prevalence, abundance, and intensity of infection were greatest in spring and fall months off the Florida panhandle. Furthermore, the abundance and intensity of infection correlated negatively with fork length, weight, and gonad weight of mature fish but positively with longitude. Therefore, smaller adult fish tended to be more infected than larger adults, and prevalence and intensity increased from west to east (Louisiana to Florida). Spatial and temporal trends seemed to result from physical factors (e.g., water temperature, salinity, bottom type), but they also coincided with the annual migration of S. maculatus as fish moved northward along the GOM coastline from the southern tip of Florida in the spring months and returned in the fall, being present in the north-central GOM from late spring through fall. This pattern suggests the possibility that acquisition of infections occurred from a molluscan host in waters off the Florida panhandle.

A Climatology of Southern Appalachian Cold-Air Damming*

Abstract A 30-yr climatology (1981–2010) of cold-air damming (CAD) events in the southern Appalachians was conducted using hourly surface observations and North American Regional Reanalysis (NARR) data. Analysis of the spatial distribution and frequency of these events reveals that some part of the Southeast is affected by CAD on 50 days out of each year, and even the northern Florida panhandle and much of Alabama experience CAD conditions on about 30 days annually. Spatially, different CAD types tend to exhibit one of two patterns in the southernmost extent of the cold-air dome: a more southerly dome with a ridge axis oriented from north-northeast to south-southwest or a more westerly dome with a ridge axis in a northeast to west-southwest orientation. These patterns may be the result of both splitting around the region of higher terrain in east-central Alabama and Coriolis forcing in stronger CAD types with higher wind speeds. Analysis of the frequency of CAD by type on a month-by-month and year-by-year basis confirms previous work that CAD is much more frequent during the cold season versus the warm season, with CAD occurring on 6.8 days month−1 during December and only 1.3 days month−1 during July. Analysis was also stratified by CAD type, revealing that weak/dry events were the most common. Classical type events with stronger and more favorably positioned parent highs exhibited the longest average duration, nearly 45 h, while other CAD types averaged approximately half as long.

Quantitative comparative geomorpholgical analysis of fluvial and karst relief of Florida

Karst relief of Central Florida and fluvial relief of the Florida Panhandle were analyzed and compared on the basis of standardized samples of karst and fluvial topography derived from digital databases in a GIS environment. Comparative geomorphological analyses of the two distinct genetic relief types were performed on the basis of morphometric parameters derived for each type of relief in general as well as differentially for hypsometric intervals of paleo-marine terraces with the assumption of relative stability of tectonic conditions of the underlying carbonate platform. The comparative analyses conducted indicate overall higher values of the morphometric parameters in the fluvial relief compared to those in the karst relief. This is a consequence of more than two times higher rates of fluvial denudation compared to the karst denudation rates (0.23 vs. 0.11 mm/year, respectively). Differential analyses with respect to the paleo-marine terrace intervals reveal significant quantitative morphological differences between the upper, older and lower, younger terrace intervals in the karst and fluvial relief. In the two older terrace intervals, fluvial and karst denudation rates range from 0.07 to 0.09 mm/year, while in the younger terrace intervals fluvial denudation shows more than two times higher rates than the karst denudation (0.22 and 0.55 vs. 0.11 and 0.19 mm/year), indicating that fluvial processes in the study area are more effective than the respective karst processes. This is clearly reflected in the higher values of vertical dissection and denudated sediment volume in the fluvial relief in the younger terrace intervals, while the increased karst denudation rates are not yet reflected in the respective morphometric parameters due to the slower morphologic response. Overall, long-term karst denudation ranging from 0.07 to 0.19 mm/year is derived by volumetric analysis of the denudated sediment and as such accounts for the effects of both chemical and mechanical denudation. Consequently, they are significantly higher than the previously calculated short-term solutional denudation rates, although their values fall in the mid range of theoretical estimations with respect to climatic conditions of the study area. The obtained fluvial denudation rates ranging from 0.07 to 0.55 mm/year are similar to previous estimates of long-term fluvial denudation.

14C Variations in Pre-Bomb Nearshore Habitats of the Florida Panhandle, USA

This article presents radiocarbon data for known-age, pre-bomb marine gastropods, Busycon sinistrum and Strombus alatus , collected between AD 1924 and 1946 from nearshore environments of the Florida Panhandle, on the northern Gulf of Mexico. Δ 14 C was measured in whole crushed juvenile specimens ( n = 7) and terminal edges of adult specimens ( n = 6). A subsample of adult specimens ( n = 3) was subjected to additional, intrashell sampling to observe short-term variability in 14 C conditions. Δ 14 C values were consistent within and among B. sinistrum specimens, and we propose a reservoir age offset (ΔR) of –9 ± 25 14 C yr for B. sinistrum from the northwest coast of Florida. S. alatus shells exhibited significant variability from one individual to another, and also within individual specimens. ΔR values for S. alatus range from –3 ± 30 to 659 ± 30 14 C yr. These differences may result from a combination of factors, including subregional variability in inputs of 14 C-depleted waters and life-history factors including mobility, mode of feeding, and ontogenetic niche shifts. DOI: 10.2458/azu_rc.57.18353

A New Species ofMyrmecina(Hymenoptera: Formicidae) from Southeastern North America

A new species of ant, Myrmecina cooperi sp. nov. (Hymenoptera: Formicidae: Myrmecinae) is described and illustrated from specimens collected in Florida and Alabama, USA. This species is characterized by its small size (under 2 mm length), shagreened gastral tergites, and a strong ventral protrusion on the underside of the postpetiole. It is presently known from a small area in the Florida Panhandle and adjacent Alabama. Habitus illustrations and an identification key are provided for the 3 eastern species of Myrmecina.

Manduca rustica(Lepidoptera: Sphingidae) Damage on Olive (Olea europaea; Lamiales: Oleaceae) trees in Florida

There is a growing interest in cultivating olives Olea europaea L. (Lamiales: Oleaceae) in Florida, USA. Although some parts of Florida seem well suited for olive production, the pests and diseases associ ated with cultivated olives in Florida are generally unknown. During a 2014 survey of olives being grown at the commercial and homeowner level, a novel pest was identified. A hornworm (Fig. 1), now known to be the larval stage of the rustic sphinx Manduca rustica (F.) (Lepidoptera: Sphingidae) (Wagner 2010; D. L. Wagner, personal communication), was reported as a pest of concern by growers from the Florida Panhandle in the north to Polk County in the south. Tuttle (2007) described M. rustica as a broadly distributed Neotropical species that breeds in the mid-Atlantic states as far north as Delaware, USA. In Florida, Heppner (2003) reported M. rustica ranges as far south as Miami-Dade County, but the species has not been reported from Monroe County (the Florida Keys).Worldwide, there are 49 recorded lepidopteran pests of O. europaea, 9 of which are in the family Sphingidae, but none is within the genus Manduca (Robinson et al. 2010). The primary concern of growers was the defoliation caused by larval feeding. One larva can quickly denude a 2-yr-old olive tree, causing problems for nursery producers and for growers with new plantings. Although trees can recover from this damage, olive trees are slow growing, and feeding damage can remain apparent for several months depending on the time of year. Manduca rustica is listed as having a host range that includes plants in the family Oleaceae (Kitching & Cadiou 2000; Tuttle 2007; Robinson et al. 2010); however, we were unable to find any report that it has been recorded as feeding on O. europaea. The rustic sphinx moth is recognized as a pollinator in the southeastern United States (Graham 2010). The only notable report of the rustic sphinx as a pest comes from Clavijo & Chacin (1992), who reported M. rustica as a pest of sesame in Venezuela. This is important to note for growers who are interested in using sesame as a cover crop or an attractant for beneficial insects near olive production areas in Florida. Initial reports from growers included photos of specimens collected from orchards and nurseries. Many growers elected to control mechani

Finite element modeling of propagation and reverberation shallow water waveguide with a variable environment

Shallow water waveguides can exhibit environmental variability in the water column, on the bottom interface and in the sediment. Finite element models provide a method to capture the effects of this variability since every element can be described by a different sound speed and density. However, fully three-dimensional finite element models are often computationally inaccessible due to extreme memory requirements. In this study, a longitudinally invariant finite element model is used to predict the reverberation from a shallow water waveguide described by environmental measurements at the Target and Reverberation Experiment 2013 conducted off the coast of the Florida panhandle. Longitudinally invariant models retain all of the fidelity of a three-dimensional model with the requirement that one geometric dimension must be invariant. Therefore, it is an ideal model for wedges and ridges. In this case, the longitudinally invariant direction describes the sand ripples. The reverberation with and without variations in sediment sound speed and density will be compared for the same bathymetry to determine the role of sediment variability in reverberation. Reverberation from along and across the sand ridges will also be examined. [Work supported by ONR, Ocean Acoustics.]

Impact of age, race and socio-economic status on temporal trends in late-stage prostate cancer diagnosis in Florida

Individual-level data from the Florida Cancer Data System (1981–2007) were analyzed to explore temporal trends of prostate cancer late-stage diagnosis, and how they vary based on race, income and age. Annual census-tract rates were computed for two races (white and black) and two age categories (40–65, >65) before being aggregated according to census tract median household incomes. Joinpoint regression and a new disparity statistic were applied to model temporal trends and detect potential racial and socio-economic differences. Multi-dimensional scaling was used as an innovative way to visualize similarities among temporal trends in a 2-D space. Analysis of time-series indicated that late-stage diagnosis was generally more prevalent among blacks, for age category 40–64 compared to older patients covered by Medicare, and among classes of lower socio-economic status. Joinpoint regression also showed that the rate of decline in late-stage diagnosis was similar among older patients. For younger patients, the decline occurred at a faster pace for blacks with rates becoming similar to whites in the late 1990s, in particular for higher incomes. Both races displayed distinct spatial patterns with higher rates of late-stage diagnosis in the Florida Panhandle for whites whereas high rates clustered in South-eastern Florida for blacks.

Vanduzea segmentata (Fowler) (Hemiptera: Membracidae): Seasonality and Habits in the Southeastern United States, with Review of Its U.S. Distribution and Host Plants

Abstract.— Vanduzea segmentata, a membracid of the smiliine tribe Amastrini, was known only from the western United States and Mexico until it was reported from Louisiana in the 1930s. A collection in the Florida Panhandle in 1954 represented the first record east of the Mississippi River; the first record from peninsular Florida was 2001. The membracid has remained known in southeastern states only from Florida and Louisiana, with scant data available on its bionomics. We give the first records of V. segmentata from Alabama and Georgia, noting features that distinguish it from other species of Vanduzea in the Southeast, and review its previously published U.S. distribution and plant associations. We found nymphs and adults mainly on mimosa, or silk tree (Albizia julibrissin Durazz.; Fabaceae), but other fabaceous species and composites (Asteraceae) also were hosts. Periodic sampling of mimosa in southeastern Georgia indicated that the membracid is trivoltine, with overwintered eggs beginning to hatch in ...

Urbanization effects on soil nitrogen transformations and microbial biomass in the subtropics

As urbanization can involve multiple alterations to the soil environment, it is uncertain how urbanization effects soil nitrogen cycling. We established 22–0.04 ha plots in six different land cover types—rural slash pine (Pinus elliottii) plantations (n = 3), rural natural pine forests (n = 3), rural natural oak forests (n = 4), urban pine forests (n = 3), urban oak forests (n = 4) and urban lawns (n = 5) to investigate how net soil nitrogen mineralization rates and soil microbial biomass differed between urban forests and rural forests and between urban forests and urban lawns in the Florida panhandle. Urban forest sites have 2.5 times as much net total nitrogen mineralized than rural forest sites based on the mean daily rates averaged over the 2 years study (2010–2012). Urbanization may increase soil microbial biomass and activity (potential carbon mineralization rates) and this may be influencing the soil nitrogen mineralization rates in the forest sites. To include an urban lawn (turfgrass) component in the study, one time measurements of soils from the aforementioned forest sites and from urban lawn sites (no fertilization, no irrigation) were collected in 2012. Urban forest sites and urban lawns sites do not differ in their potential carbon mineralization rates, potential net total nitrogen mineralization rates or microbial biomass carbon and nitrogen contents. However, lawns have a higher potential net nitrification rate compared to urban forests.

Temporal and spatial availability of Atlantic Thread Herring, Opisthonema oglinum, in relation to oceanographic drivers and fishery landings on the Florida Panhandle

AbstractSince 1995, landings of Atlantic Thread Herring (Opisthonema oglinum) on the Florida Panhandle averaged 124 mt each spring (April–June) but declined to nearly zero in 1996–97 and 2006. To elucidate causes of recurring periods of low landings, we used generalized additive mixed models (GAMMs) to examine the relationship between Atlantic Thread Herring catch in a trawl survey on the west‐central coast of Florida and four environmental variables. Chlorophyll‐a was significant in the models, indicating a direct relationship between local abundance of baitfish and their planktonic food. Temperature and depth were also significant whereas salinity was not. During 2003 and 2012, synoptic satellite‐derived temperature and chlorophyll‐a maps were used with the GAMMs to predict monthly spatial availability on the Florida Panhandle fishing grounds (long. 85–88o W and depth 12–25 m). The predicted monthly availability was significantly correlated with commercial catch rates (Pearson's r = 0.26, P = 0.004, d.f. = 118). We used multiple linear regression (MLR) with lags to describe the effect of river discharge and wind (as a transport mechanism) on surface chlorophyll‐a over the Panhandle fishing grounds. Discharge from local rivers was significant in all MLRs, and the Mississippi was only significant as an interaction with wind. We conclude that Atlantic Thread Herring are distributed over the Panhandle fishing grounds based on food availability that is driven by river discharge and eastward transport of Mississippi River plumes. This analysis improves our understating of baitfish dynamics, an important ecosystem component in the Gulf of Mexico.