FORENSIC METHODS FOR CHARACTERIZING WATERCRAFT FROM WATERCRAFT-INDUCED WOUNDS ON THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS)

Watercraft-related mortality represents 1,253 (24.9%) of 5,033 Florida manatee ( Trichechus manatus latirostris ) deaths recorded between 1 January 1979 and 31 December 2004. Wound patterns generated by collisions with watercraft are diagnostic. Sets of cuts and scrapes that are roughly equidistant and perpendicular to the direction of vessel travel are consistent with lacerations made by propeller blades. From these lesions, estimates of propeller diameter, pitch, rotation, and direction of travel may be obtained. Considerable overlap of propeller sizes and pitches on different size vessels, common use of counter rotation propellers, and numerous other complicating factors may confound efforts to accurately predict vessel size and type from propeller wounds. Of the more than one million watercraft registered in Florida, 98% are ≤12.2 m (40 ft), yet watercraft 5.3–36.6 m (17.5–120 ft) are known to have killed manatees. Analysis of a 5-yr subset of mortality data suggests that a disproportionate number of propeller-caused watercraft-related mortalities could be attributed to propeller diameters ≥43.2 cm (17 in.), inferring that these were caused by watercraft ≥12.2 m (40 ft).     

Investigating Support for Management of the Pet Trade Invasion Risk

The non-native pet trade contributes directly to species invasions, thereby threatening wildlife. Biological invasions influence environmental change, resulting in species extinctions and biodiversity loss. To mitigate the pet trade invasion risk, interventions are required to prevent trade in non-native animals with high invasion potential, impulse or ill-informed purchases of non-native pets by individuals who may release these animals, and the deliberate release of non-native animals by pet owners. Interventions are also required to prevent the establishment of non-native animals that have been released by pet owners (e.g., euthanasia). The successful implementation of these interventions depends on the support of pet owners and the public in the form of political support for, and compliance with, interventions. In 2017–2018, using both mail and online surveys, we measured the support of 1,171 members of the public and 550 owners of non-native pets in Florida, USA, for 7 different interventions to mitigate the pet trade invasion risk, and we investigated determinants of this support. We found that individuals' support for interventions depended on their concern related to the invasion risks associated with the pet trade, trust in government to manage the pet trade, perceptions of how effective interventions would be in mitigating the pet trade invasion risk, and demographic characteristics. Support for interventions differed across pet owners and the public. Educating pet owners about the traits and cost of care for non-native animals and providing them with options to relinquish unwanted pets may reduce the pet trade invasion risk. Engaging the pet trade in the design of interventions to mitigate invasion risks is likely important to attain voluntary compliance with these interventions. The effectiveness of interventions also depends on enforcement by agencies. Implementing interventions that effectively reduce the pet trade invasion risk is important to protect native and endangered wildlife. © 2020 The Wildlife Society.     

Florida red tide knowledge and risk perception: Is there a need for tailored messaging

Harmful algal blooms of the toxic dinoflagellate, Karenia brevis, occur throughout the Gulf of Mexico. Recent research efforts sponsored by the National Institute of Environmental Health Sciences (NIEHS) and others found that Florida red tide causes both acute and possibly chronic health effects from the toxic aerosols. Florida red tide also demonstrated significant social and economic impacts to both coastal residents and visitors. In conjunction with the research, persistent outreach efforts were conducted over the 11-year period. The goal of this project was to assess potential needs for tailored messaging needed among different red tide information user groups. Survey participants included 303 local residents, both with asthma and without, and ‘snowbirds (seasonal residents that reside in the Sarasota area for more than 3 months but less than 6 months/year), also both with asthma and without. The questionnaire assessed Florida red tide knowledge and risk perception regarding Florida red tide using items drawn from two previously published surveys to allow comparison. Our results reveal that overall knowledge of Florida red tide has not changed. We found that knowledge was consistent across our selected groups and also did not vary by age, gender and education level. However, knowledge regarding consumption of seafood during Florida red tide has declined. Risk perception increased significantly for people who have asthma. Individuals responsible for public health communication regarding Florida red tide and human health concerns need to continue to pursue more effective outreach messages and delivery methods.     

Review of salinity effects on abundance,growth, and survival of nearshore life stages of pink shrimp (Farfantepenaeus duorarum)

The pink shrimp (Farfantepenaeus duorarum) has been selected as an ecological indicator to assess ecological effects on estuaries of implementation of the Comprehensive Everglades Restoration Plan that seeks to restore historical freshwater flows and nearshore salinity regimes in southern Florida. Concern over altered freshwater delivery impacts on pink shrimp productivity was expressed as early as the 1960s. The present review assessed pink shrimp scientific literature of the past 75+ years (>500 publications) to glean information relevant to understanding potential influence of freshwater management on pink shrimp productivity. The review was organized around “Essential Fish Habitat” metrics concerning abundance, growth, survival, distribution, productivity, and behavior. It summarizes previous pink shrimp field, laboratory, and modeling studies. Where possible, statistical analyses and meta-analyses of previously published data were performed to investigate consistency among independent findings. Pink shrimp occur in a wide range of salinities (0.5–67 ppt). A majority of studies (53.3%) reported maximal abundance between ∼20 to 35 ppt salinities. One laboratory study reported maximal growth at 30 ppt. Meta-analysis of reported growth rates did not yield results due to non-convergence of regression models. Reported survival was maximal at ∼30 ppt and remained high (>80% survival) across salinities of ∼15 to 40 ppt. A regression model that combined survival data across studies confirmed a previously reported parabolic relationship between salinity and survival; in this regression, 35 ppt maximized survival. Productivity, conditional upon survival and growth, was maximized at polyhaline (18–30 ppt) conditions. Inshore hypersalinity (>40 ppt) may elicit young pink shrimp behavioral cues counterproductive to settlement in nearshore areas. Virtually no information exists regarding postlarval pink shrimp movement or preference relative to salinity gradients. Realization and preservation of nearshore polyhaline conditions and elimination of hypersalinity should maximize growth, survival, and density, thus improving pink shrimp productivity. New and updated statistical models predicting pink shrimp distribution, abundance, growth, survival, and productivity relative to salinity conditions are needed to better guide freshwater management decisions.     

Effects of fire on long-unburned Florida uplands

Abstract. The widespread suppression of fire during the 20th century has created extensive areas of fire-prone ecosystems that are in long-unburned condition. Plant species of flatwoods and scrubby flatwoods (= oak scrub) in the southeastern USA possess adaptations that facilitate resprouting, clonal spread, or seeding following fire. While the majority of the woody species of these associations can persist for long periods without fire, fire suppression reduces the populations of ephemeral herbs. Long-unburned (> 35 yr) flatwoods and scrubby flatwoods were burned after five annual vegetation censuses. Both stands were resampled five times over a >8-yr recovery period. One recently burned (<20 yr) flatwoods and two recently burned scrubby flatwoods were censused prior to fire and were recensused over a 5-yr or 11-yr period following fire depending on the stand. In spite of the variety of recovery strategies and time since fire, there were limited changes in the compositions and structures of post-burn stands compared to their preburn states. Detrended Correspondence Analysis showed that recently burned stands returned to preburn states within 1–2 yr. However, the reintroduction of a single fire to long-unburned stands did not restore the populations of herbs typical of recently burned stands. Our results suggest that a single fire may not be effective in restoring flatwoods and scrubby flatwoods that have experienced fire suppression to states more characteristic of recently burned stands.     

Substitution of norleucine for methionine residues in a crustacean pigment-dispersing hormone

In order to evaluate the structural/functional roles of Met residues in an octadecapeptide pigment-dispersing hormone (PDH: Asn-Ser-Gly-Met-Ile-Asn-Ser-Ile-Leu-Gly-Ile-Pro-Arg-Val-Met-Thr-Glu-Ala- NH2), first described as light-adapting distal retinal pigment hormone (DRPH) from Pandalus, three analogs were synthesized: Nle4-PDH, Nle15-PDH, and Nle4,15-PDH. When tested for melanophore pigment-dispersing activity in destalked Uca, all three Nle-analogs were more potent than unsubstituted PDH. Performic acid oxidation caused a marked loss of potency of PDH, Nle4-PDH, and Nle15-PDH. The analog Nle4,15-PDH was resistant to oxidation and displayed 6-fold higher potency than PDH. Thus Met4 and Met15 are not essential for the PDH activity. The oxidation-induced loss of activity of unsubstituted PDH may result from introduction of oxygen (in methionine sulfone) and a consequent conformational change in the octadecapeptide.     

Factors affecting Florida scrub-jay nest survival on Ocala National Forest,Florida

One of the main populations of the Florida scrub-jay (Aphelocoma coerulescens), a federally threatened species, occurs on Ocala National Forest, Florida. We determined the nest daily survival rate (DSR) of 474 nests of Florida scrub-jays in stands subject to sand pine reforestation management after timber harvesting or wildfire on Ocala National Forest. We used the information-theoretic approach with logistic-exposure modeling to determine the most likely models to account for DSR for the incubation and nestling stages separately. The models consisted of 4 components (temporal, management, habitat, and helpers) with each consisting of one to several specific variables. In the incubation stage all the best models included the temporal component alone or in concert with the habitat, helpers, or habitat and helpers components. Model averaging in the incubation stage indicated support for the year and day × year in the temporal component and stand age in the habitat component. In the nestling stage, top models all included the temporal component alone or with helpers or habitat, helpers, and the interaction of habitat and helpers. Model averaging in the nestling stage showed support for the year, nest age, and to a lesser extent day in the temporal component and helpers. The management component, which consisted of no site preparation, wildfire burn, post-harvest burn, chop and seed, or seed only, had little influence on nest survival for the incubation or nestling stages. However, we identified several other management factors that may increase Florida scrub-jay populations despite having no effect on DSR. First, the proportion of Florida scrub-jay nests was significantly higher than expected in burned habitat based on habitat availability, indicating a potential preferred nesting habitat conducive to population growth. Second, incubation stage DSR with respect to stand age (habitat component) declined to stand age 10 yr and then began to increase, which may be attributed to the higher bird population in the prime habitat in the middle stand ages. The denser population may result in more competition for resources, and possibly may attract more predators, resulting in a lower DSR. Thus, although DSR may be lower at the mid-stand ages, the overall population may actually be optimal. Therefore, to increase the Florida scrub-jay population on Ocala National Forest, we recommend maintaining a mosaic of stands ≤20 yr of age and emphasizing natural reseeding and site preparation via burning. © 2011 The Wildlife Society.