Scholarly Works, Fish and Wildlife Conservation

Permanent URI for this collection

https://hdl.handle.net/10919/24280

Research articles, presentations, and other scholarship

Browse

Now showing 1 - 20 of 540

Prescribed fire promotes colonization by the Florida bog frog
Brooks, George C.; Gorman, Thomas A.; Proctor, Christine M.; Rincon, Brandon K.; Haas, Carola A. (2025-04-09)
Background: Understanding the link between prescribed fire and occupancy dynamics can aid in managing at-risk species. Knowledge of how fire return interval influences rates of colonization and persistence is essential to effectively mitigate extinction risk, particularly for species endemic to fire-maintained habitats with restricted geographic ranges. The current geographic range of the Florida bog frog (Rana okaloosae, hereafter bog frog) is largely restricted to one military installation in the Florida panhandle. The bog frog is currently listed as a state species of special concern owing to its inherent rarity and habitat loss across its limited range. We conducted call surveys for bog frogs at 151 stream-associated sites on Eglin Air Force Base from 2006 to 2022 to map their distribution and evaluate the effectiveness of habitat management. We constructed a spatially explicit, dynamic occupancy model to identify habitat characteristics associated with bog frog presence and quantify the effect of prescribed fire on turnover dynamics. Results: Historical fire return interval was the only predictor of initial site occupancy; sites that burnt every 2 years on average from 1985 to 2005 were twice as likely to be occupied in 2006 as sites that burnt once every 10 years in that time period. Additionally, we found that colonization rates were a function of proximity to neighboring sites and burn frequency. Most dispersal events occurred between sites less than 0.33 km apart and unoccupied sites more than 2 km from their nearest neighbors were never colonized. Colonization rates were higher at sites that had seen an increase in burn frequency during the study period compared to the preceding two decades. Conclusions: The bog frog benefits from frequent fire in its native stream habitat. Conservation activities should focus on protecting high-quality sites and targeted burns to restore fire-suppressed sites near occupied sites. More broadly, our study highlights the value of long-term monitoring to ensure management activities for at-risk species match the scale of dynamic biological processes.
Hantavirus in rodents in the United States: Temporal and spatial trends and report of new hosts
Astorga, Francisca; Alkishe, Abdelghafar; Paansri, Paanwaris; Mantilla, Gabriel; Escobar, Luis E. (Wiley, 2025-03-16)
In North America, the rodent-borne hantavirus pulmonary syndrome ispredominantly caused by the Sin Nombre virus, typically associated with the deer mouse Peromyscus maniculatus. Utilizing data from the National Ecological Observatory Network (NEON) hantavirus program, we assessed factors that may influence the spatial and temporal distribution of hantavirus inrodent populations across the United States. Between 2014 and 2019, the NEON hantavirus program conducted 104,379 small mammal captures and collected 14,004 blood samples from 49 species at 45 field sites. Our study identified 296 seropositive samples across 15 rodent species, including 8 Peromyscusspecies. We describe six new species with hantavirus seropositive samples not previously reported as hantavirus hosts. The highest number of seropositivesamples was obtained from Pe. maniculatus (n = 116; 2.9% seroprevalence),followed by Peromyscus leucopus (n = 96; 2.8%) and Microtus pennsylvanicus(n = 33; 4.2%). Hantavirus seroprevalence showed an uneven spatial distribution, with the highest seroprevalence found in Virginia (7.8%, 99 seropositivesamples), Colorado (5.7%, n = 37), and Texas (4.8%, n = 19). Hantavirus sero-positive samples were obtained from 32 sites, 10 of which presented seropositive samples in species other than Pe. maniculatus or Pe. leucopus. Seroprevalence was inconsistent across years but showed intra-annual bimodal trends, and in Pe. maniculatus and Pe. leucopus, the number of captures correlated with sero-prevalence in the following months. Seroprevalence was higher in adult males, with only one seropositive sample obtained from a juvenile Peromyscus truei. Higher body mass, presence of scrotal testes, and nonpregnant status were associated with higher seropositivity. The NEON dataset, derived from a multiyear and structured surveillance system, revealed the extensive distribution of hantavirus across broad taxonomic and environmental ranges. Future research should consider winter season surveillance and continued analyses of stored samples for a comprehensive spatiotemporal study of hantavirus circulation in wildlife. Global changes are expected to affect the dynamics of rodent populations by affecting their availability of resources and demography and, consequently, may modify transmission rates of rodent-borne zoonotic pathogens such as hantavi-rus. This study can be considered a baseline to assess hantavirus patterns across host taxa, geographies, and seasons in the United States.
Spatial epidemiology of Tabanus (Diptera: Tabanidae) vectors of Trypanosoma
Marques, Roberta; Jiménez-García, Daniel; Escobar, Luis E.; Krolow, Tiago K.; Krüger, Rodrigo F. (2025-04-03)
Background: Trypanosoma are protozoa parasites that infect animals and can cause economic losses in cattle production. Trypanosoma live in the blood and are transmitted by hematophagous insects, such as flies in the genus Tabanus. Using ecological niche models, we explored the current geography of six common Tabanus species in Brazil, which are considered vectors of Trypanosoma vivax and Tr. evansi in the Neotropics. Methods: We used georeferenced data and biotic and abiotic variables integrated using a fundamental ecological niche modeling approach. Modeling results from six Tabanus species were used to identify risk areas of Trypanosoma transmission in Latin America accounting for area predicted, landscape conditions, and density of livestock. We performed Jaccard, Schoener, and Hellinger metrics to indicate the ecological niche similarities of pairs of Tabanus species to identify known and likely vectors overlapping in distribution across geographies. Results: Our results revealed significant ecological niche similarities for two Tabanus species (T. pungens and T. sorbillans), whereas T. triangulum and T. importunus have low ecological similarity. Ecological niche models predicted risk of Trypanosoma transmission across Neotropical countries, with the highest risk in southern South America, Venezuela, and central Mexico. Conclusions: More than 1.6 billion cattle and 38 million horses are under a threat category for infection risk. Furthermore, we identified specific areas and livestock populations at high risk of trypanosomiasis in Latin America. This study reveals the areas, landscapes, and populations at risk of Trypanosoma infections in livestock in the Americas.
Assessment of 18 Years of Genetic Marker-Assisted Selection and Augmentation of Native Walleye in the Upper New River, Virginia, USA
Harris, Sheila; Palmer, George; Copeland, John R.; Williams, Joe; Hallerman, Eric M. (MDPI, 2025-03-06)
Walleye Sander vitreus is a valued sportfish in eastern North America, including the upper New River of Virginia, where individuals can grow to a large size (>7 kg). After construction of dams, especially Claytor Dam in 1939, the population declined and non-native walleye were stocked. Stocking of non-native walleye was stopped in 1997, and molecular marker data showed that the presumptive native population had persisted. To restore the native stock, selection of broodstock candidates bearing native marker alleles and hatchery-based augmentation have been practiced over a 20-year period. We evaluated the success of the marker-assisted selection and hatchery-based augmentation program. Marker-assisted selection of native New River walleye began with mean frequencies of marker alleles at microsatellite loci Svi17 and Svi33 of ~30%, and continuing selection has driven marker allele frequencies to ~65–70%. Numbers of walleye collected in fall gillnet and spring electrofishing surveys were responsive to augmentations with hatchery fish 2–3 years earlier. Stocking was not practiced in 2012–2013, and a decrease in walleye catch rates was noted in 2016, suggesting that the native New River walleye population still depends upon hatchery-based augmentation. We recommend the development of a small panel of single nucleotide polymorphism markers for more rigorous selection of broodstock representative of the native walleye population.
Environmental stress reduces shark residency to coral reefs
Williamson, Michael J.; Tebbs, Emma J.; Curnick, David J.; Ferretti, Francesco; Carlisle, Aaron B.; Chapple, Taylor K.; Schallert, Robert J.; Tickler, David M.; Block, Barbara A.; Jacoby, David M. P. (Nature Portfolio, 2024-09-09)
Coral reef ecosystems are highly threatened and can be extremely sensitive to the effects of climate change. Multiple shark species rely on coral reefs as important habitat and, as such, play a number of significant ecological roles in these ecosystems. How environmental stress impacts routine, site-attached reef shark behavior, remains relatively unexplored. Here, we combine 8 years of acoustic tracking data (2013-2020) from grey reef sharks resident to the remote coral reefs of the Chagos Archipelago in the Central Indian Ocean, with a satellite-based index of coral reef environmental stress exposure. We show that on average across the region, increased stress on the reefs significantly reduces grey reef shark residency, promoting more diffuse space use and increasing time away from shallow forereefs. Importantly, this impact has a lagged effect for up to 16 months. This may have important physiological and conservation consequences for reef sharks, as well as broader implications for reef ecosystem functioning. As climate change is predicted to increase environmental stress on coral reef ecosystems, understanding how site-attached predators respond to stress will be crucial for forecasting the functional significance of altering predator behavior and the potential impacts on conservation for both reef sharks and coral reefs themselves.
Ecological interactions between 19 shark species in the Indian Ocean
Gee, Emma; Romanov, Evgeny V.; Curnick, David; Block, Barbara; Ferretti, Francesco (IOTC, 2024-09-07)
Apex predators such as sharks are a critical component of ocean ecosystems. Yet the ecosystem consequences of shark declines remain poorly understood, primarily because of a lack of population and community baselines. The Indian Ocean is especially data-poor in ecological data, and even moreso in historical data. We utilized a longline survey dataset from 1966 through 1989 that spanned the majority of the Indian Ocean and recorded 19 shark species. This time period corresponds to the start of large-scale industrial fishing in the region. Trends across the species were highly variable; life history and fishing pressure metrics were not able to explain differences in responses between species, suggesting that changes in ecological interactions such as competition and predation had a prevalent role historically. To further explore ecological interactions between the species, we conducted a literature review of the study species’ diets with a focus on intra-guild predation. We constructed an interaction web to identify keystone species. Several species were neither predator nor prey of other sharks, suggesting that competition may be the more salient relationship to other sharks. Overall, species with broader habitat preferences and smaller individuals are now a larger part of the pelagic shark community, whereas open-ocean species have declined. These results suggest that industrial fishing restructured shark communities and diminished the top-down control of sharks in pelagic ecosystems.
SharkTrack: an accurate, generalisable software for streamlining shark and ray underwater video analysis
Varini, Filippo; Gayford, Joel H.; Jenrette, Jeremy; Witt, Matthew J.; Garzon, Francesco; Ferretti, Francesco; Wilday, Sophie; Bond, Mark E.; Heithaus, Michael; Robinson, Danielle; Carter, Devon; Gumbs, Najee; Webster, Vincent; Glocker, Ben (2024-11-30)
Elasmobranchs (shark sand rays) are critical components of coral reef ecosystems and are often considered indicators of reef health (Roff et al., 2016). Yet, they are experiencing global population declines and effective monitoring of these populations is essential to their protection. Underwater stationary videos, such as those from Baited Remote Underwater Video Stations (BRUVS), are critical for understanding elasmobranch spatial ecology and abundance. However, processing these videos requires time-consuming manual analysis. To address these challenges, we developed SharkTrack, a semi-automatic underwater video analysis software.SharkTrack uses Convolutional Neural Networks and Multi-Object Tracking to automatically detect and track elasmobranchs and provides an annotation pipeline to manually classify elasmobranch species and compute MaxN, the standard metric of relative abundance. We tested SharkTrack on BRUVS footage collected from threecoral reef locations unseen by the model during training, to demonstrate the model’sadaptability and effectiveness in different reef environments. SharkTrack computedMaxN with 89% accuracy over 207 hours of footage. The semi-automatic SharkTrackpipeline required two minutes of manual classification per hour of video, a 95%reduction of manual analysis time compared to traditional methods, estimated conservatively at 42 minutes per hour of video. These results suggest thatSharkTrack can be utilised to monitor elasmobranch populations across diverse coral reef ecosystems. Furthermore, the software’s flexible pipeline could serve as a blueprint for the development of species classifiers beyond elasmobranchs, enabling more comprehensive monitoring of coral reef biodiversity. We provide public access to SharkTrack, aiming to support future research in coral reef and marine conservation.
Position Statement on Shark Control Programs and Shark Culls
IUCN SSC Shark Specialist Group; Ferretti, Francesco (IUCN SSG. Shark Specialist Group, 2024-01-15)
The IUCN Species Survival Commission (SSC) is aware that lethal approaches to reducing the risk of human-shark interactions are increasingly being adopted around the world. Several governments either have active shark control programs (i.e., bather protection programs) or frequently implement shark culls in response to actual or perceived risk to humans. Hereby, the SSC outlines its position in relation to existing shark control programs and culls and provides context to allow managers and governments to make informed decisions when faced with delicate situations. We strongly encourage non-lethal approaches as a response and management option.
Morphological and Genetic Assessments of Coyote Diet in Qualla Boundary, North Carolina, Show Interaction with Humans
Miller, Caitlin M.; Linzey, Donald; Hallerman, Eric M. (MDPI, 2025-03-05)
Throughout the 20th century, coyotes (Canis latrans) expanded from their historical geographic range west of the Mississippi River to a current range of almost all of North America. Over the course of this expansion, coyotes have demonstrated diverse and variable omnivorous diets that change with the food resources available. This study examined the stomach contents of 25 coyotes in an area where they are relatively new, the Qualla Boundary in North Carolina, to better understand the diets of coyotes in this area. A combination of morphological identification and DNA barcoding was used to characterize the stomach contents of coyotes. Both plant and animal material were identified from anthropogenic and natural sources, the latter including native mammals. This study provides one example of the breadth and flexibility of coyote diets and helps build an understanding of how coyotes can adapt to new conditions.
How expectations of reciprocity impact donation and volunteer behavior to Nongame Wildlife Programs: a case study in Minnesota
Jennings, Kelsey K.; Dayer, Ashley A.; Chaves, Willandia A.; Osmundson, Cynthia L. (Taylor & Francis, 2025-01-11)
Our research examines motivations behind support for wildlife conservation efforts, primarily through volunteering and donations. Using the Minnesota Nongame Wildlife Program as a case study, we focus on nature-based support motivations. Using novel applications of two theoretical frameworks, we surveyed 763 respondents and found significant links between motivations and volunteer and donor behaviors. Biodiversity and ecological reciprocity were key drivers of donor behavior, while perks and natural place-based motivations strongly influenced volunteering. These findings suggest broad interests in wildlife conservation beyond organized events, extending to local communities and private lands. Our results underscore the importance of aligning volunteer experiences with preferred motivations to sustain engagement. Integrating community science programs, which activate volunteer motivations, could enhance engagement and support for wildlife conservation efforts. By focusing on supporters’ conservation impact and broadening engagement strategies for donors and volunteers, conservation organizations can adapt to changing landscapes and foster long-term support for wildlife conservation.
Demographic feedbacks during evolutionary rescue can slow or speed adaptive evolution
Draghi, Jeremy A.; McGlothlin, Joel W.; Kindsvater, Holly K. (The Royal Society, 2024-02-14)
Populations declining toward extinction can persist via genetic adaptation in a process called evolutionary rescue. Predicting evolutionary rescue has applications ranging from conservation biology to medicine, but requires understanding and integrating the multiple effects of a stressful environmental change on population processes. Here we derive a simple expression for how generation time, a key determinant of the rate of evolution, varies with population size during evolutionary rescue. Change in generation time is quantitatively predicted by comparing how intraspecific competition and the source of maladaptation each affect the rates of births and deaths in the population. Depending on the difference between two parameters quantifying these effects, the model predicts that populations may experience substantial changes in their rate of adaptation in both positive and negative directions, or adapt consistently despite severe stress. These predictions were then tested by comparison to the results of individual-based simulations of evolutionary rescue, which validated that the tolerable rate of environmental change varied considerably as described by analytical results. We discuss how these results inform efforts to understand wildlife disease and adaptation to climate change, evolution in managed populations and treatment resistance in pathogens.
Characterization of Diarrheagenic Escherichia coli and Salmonella enterica from Produce in the Chobe District of Botswana
Bywater, Auja; Dintwe, Galaletsang; Alexander, Kathleen A.; Ponder, Monica A. (Elsevier, 2024-08-24)
Diarrheal disease is a leading cause of death in children in low- and moderate-income countries. Fresh produce, including fruits and vegetables, may harbor diarrheal disease-causing bacteria including strains of Salmonella enterica and Escherichia coli. This study aimed to determine the prevalence and antibiotic resistance profiles of S. enterica and E. coli isolated from produce samples (n = 207) obtained from retail markets in northern Botswana in Chobe District of Botswana in 2022. Samples were enriched in the appropriate selective media: Brilliant Green Bile Broth for E. coli and Rappaport Vassiliadis Broth for S. enterica. E. coli were confirmed by PCR detecting the phoA gene, and classified as potentially pathogenic through screening for the eae, stx, and stx2 and estIb genes. S. enterica isolates were confirmed using invA primers. Isolates were evaluated for resistance to ampicillin, amoxicillin-clavulanic acid, chloramphenicol, cefotaxime, doxycycline, streptomycin, sulfamethoxazole, and tetracycline antibiotic using the Kirby-Bauer Disk Diffusion method. E. coli was isolated from 15.5% of produce samples (n = 207). The gene eae was detected from 1.5% of samples, while stx1, stx2, and estIb were not detected. Resistance to one or more antibiotics was common (72%) with the majority of the resistant E. coli (n = 32) isolated from fruits (22%) and greens (18%) compared to other types of vegetables. Multidrug resistance (MDR, resistant to 3 or more antibiotics) was identified in 18% of samples. S. enterica was isolated from 3.4% of produce samples (7, n = 207). Resistance was uncommon among the S. enterica isolates (1/7). Overall prevalence of diarrheagenic S. enterica and E. coli was low; however, their presence and that of MDR E. coli in foods commonly consumed raw increases the risk to vulnerable populations. Strategies to reduce contamination of fresh produce and public education on washing and cooking some types of produce may be useful to reduce disease.
Antibiotic Resistance Profiles of Escherichia coli isolated from Chobe River water in the Northern Botswana
Fleming, Madison; Yi, Saehah; Ponder, Monica A.; Patino, Lena; Alexander, Kathleen A. (2024-04-26)
Antibiotic Resistance Profiles of Escherichia coli Isolated from Elephants in the Chobe Region of Botswana
Haddadin, Maisoon; Patino, Lena; Ponder, Monica A.; Alexander, Kathleen A. (2024-04-26)
Characterization of Escherichia coli isolated from poultry in the Chobe region of Botswana by molecular methods
Yi, Saehah; Bywater, Auja; Dintwe, Galaletsang; Haidl, Thomas; Cameron, Andrew; Ponder, Monica A.; Alexander, Kathleen A. (2024-07-15)
Introduction: Diarrheal illness incidence is high in rural dryland environments, including the Chobe region of Botswana, where peaks are often associated with high rainfall events. Antibiotic resistance (ABR) is also a growing problem in the region. Contributions of poultry to diarrheal illness and ABR in the region are not well understood. Purpose: Characterize the virulence potential and ABR of E.coli isolated from chicken purchased from local vendors in Botswana using molecular techniques, including whole genome sequencing. Methods: Poultry was purchased in Kasane, Botswana and enriched within 24h. E.coli was isolated using MacConkey and EMB agar. Isolates were shipped to Virginia Tech for molecular and antibiotic resistance characterization. Multiplex PCR was used to detect presence of genes phoA (all E.coli), and diarrheagenic E.coli (eae, and est1b). Phenotypic ABR was determined using CLSI disk diffusion methods. Whole genome sequencing was performed using an Illumina MiSeq system and genome annotated using BV-BRC. Results: E.coli was isolated from 62% (38/61) of poultry samples. Five isolates were classified as diarrheagenic based on eae, none were positive for est1LB. Multidrug resistance (3+) was seen in 26 isolates and resistance to 1 or more antibiotics in 41 E.coli isolates. Resistance amongst chicken isolates was as follows: tetracycline (29), doxycycline (21), sulfamethoxazole (20), streptomycin (15), ampicillin (15), chloramphenicol (9), ciprofloxacin (6), gentamicin (4), c ceftriaxone (4), amoxicillin-clavulanic acid (3) and azithromycin (1). Comprehensive analysis of the genomes from chicken intestinal isolates revealed large numbers of virulence genes (125-252) common amongst diarrheagenic E.coli. Antibiotic resistance genes (65-85) were also present including those encoding resistance to ampicillin, ceftriaxone, doxycycline, streptomycin, and tetracycline. Significance: While prevalence of diarrheagenic E.coli was low, antibiotic resistant E.coli were frequently isolated. E.coli may be an important sentinel species to evaluate ABR emergence and effectiveness of control strategies by Botswana poultry producers.
Environmental complexity impacts anxiety in broiler chickens depending on genetic strain and body weight
Ulans, Alexandra; Brooks, George C.; Jacobs, Leonie (Nature Portfolio, 2024-07-30)
The objective was to assess the impact of environmental complexity on affective state (anxiety) in fast- and slow-growing broilers (Gallus gallus domesticus) as they gain weight. Six hundred fast-growing broilers (Ross 708; “fast-growers”) and 600 slow-growing broilers (Hubbard Redbro Mini; “slow-growers”) were raised in 24 pens with simple (standard; SE) or complex (permanent and temporary enrichments; CE) environments. Six birds/pen underwent the attention bias test on day 23 (fast-growers only), 28–29, 35–36, 42–43, and 56–57 (slow-growers only), with individuals only tested once (n = 576). Proportion of birds feeding, time spent vigilant and latencies to eat and step were recorded. Greater vigilance and longer latencies indicate more anxiety. Slow-growers fed more (p = 0.001), were less vigilant (p = 0.003), and stepped sooner than fast-growers (p = 0.007). For both strains, likelihood of feeding was unrelated to weight in SE, but decreased with increasing weight in CE (p = 0.048). Birds in CE stepped sooner than birds in SE (p = 0.030). Vigilance increased with body weight (p = 0.024). These results indicate that affective state (anxiety) can change as birds gain weight, depending on environmental complexity and genetic strain. Overall, slow-growers showed reduced anxiety compared to fast-growers, across housing treatments or weights.
First satellite track of a juvenile shortfin mako shark (Isurus oxyrinchus) in the Mediterranean Sea
Shea, Brendan D.; Chapple, Taylor K.; Echwikhi, Khaled; Gambardella, Chiara; Jenrette, Jeremy F.; Moro, Stefano; Schallert, Robert J.; Block, Barbara A.; Ferretti, Francesco (Frontiers, 2024-12-09)
The shortfin mako shark (Isurus oxyrinchus) is a highly mobile, coastal littoral, and epipelagic oceanic species broadly distributed in tropical, subtropical, and temperate seas worldwide (Rigby et al., 2019). In recent years, there has been growing recognition of the impacts of overfishing on shortfin mako populations, and the species is now listed as Endangered by the International Union for the Conservation of Nature (IUCN) (Rigby et al., 2019). The species is listed as Critically Endangered in the Mediterranean Sea due to long-term and continuing exploitation coupled with inadequate management (Walls and Soldo, 2016). Of particular concern is the ongoing capture of juvenile mako sharks in the Central Mediterranean and the Strait of Sicily, which have been identified as potential nursery areas (Walls and Soldo, 2016; Cattano et al., 2023; Mancusi et al., 2023). Even with significant declines in pelagic sharks regionally (Ferretti et al., 2008), sharks continue to be occasionally targeted in the Mediterranean Sea, though the most critical risk to shark populations in the region is bycatch in other fisheries (Bradai et al., 2018; Carpentieri et al., 2021). In the Mediterranean, most fishers typically retain their shark bycatch, with some estimates of shark discard rates as low as 1% (Megalofonou et al., 2005) even for protected species, though discard rates are likely to vary by season and gear (Carpentieri et al., 2021). Despite their imperiled status, shortfin mako sharks remain one of the region’s commonly encountered sharks for fishers, especially for longlines (Carpentieri et al., 2021), and sharks are typically retained despite falling under regional protections such as the Bern Convention, Bonn Convention, and Barcelona Convention (Serena et al., 2014). Of additional concern is the relatively unmonitored recreational fishery, which may additionally encounter high numbers of shortfin mako sharks, many of Frontiers in which are retained, but the scale of this fishery is not well known (Udovičić et al., 2019; Panayiotou et al., 2020). Concerningly, young-of-the-year (YOY) and juvenile specimens comprise the bulk of captured individuals reported in the Mediterranean (Saidi et al., 2019; Udovičić et al., 2019; Panayiotou et al., 2020; Cattano et al., 2023; Mancusi et al., 2023; Scacco et al., 2023). Given the life history of shortfin mako sharks, particularly their advanced age at maturity (Natanson et al., 2020), this frequent and ongoing capture of juvenile sharks represents a severe threat to regional populations, as many sharks will never reach maturity, let alone successfully reproduce. These losses highlight the need for more detailed information regarding the movement patterns and space use of juvenile shortfin mako sharks, for which little is known in the Mediterranean. In recent years, a proliferation of telemetry studies has drastically improved our understanding of themovements and space use of large marine predators like shortfin mako sharks around the globe (Queiroz et al., 2019); however, virtually no study has focused on Mediterranean populations, especially sharks. Here, we report the satellite track from a pop-off archival tag (PAT) deployed on a juvenile shortfin mako shark in the Mediterranean Sea in May 2023. To our knowledge, this track represents the first satellite tag deployed on a shortfin mako shark in the Mediterranean Sea. We describe the horizontal and vertical movements the study shark performed over 54 days at liberty (DAL), discussing potential drivers for the observed movements and the implications of the track for the conservation of shortfin mako sharks regionally.
Social support and identity promote diverse participation in wildlife viewing
Jennings, Kelsey K.; Dayer, Ashley A.; Chaves, Willandia A. (Wiley, 2024-08-07)
1. Wildlife viewing is growing in popularity, especially among Black, Indigenous and people of colour (BIPOC), whose participation has increased dramatically in the last 20 years. We used a nationwide sample of wildlife viewers to examine how identity as a wildlife viewer, the importance of wildlife viewing to one's life, ethnoracial identity and social support influenced the degree of participation in wildlife viewing. 2. We examined data as part of a non-probabilistic online survey of wildlife viewers (n = 17,104). We were particularly interested in how participation, support, the importance of wildlife viewing, and identity as wildlife viewers varied across ethnoracial groups. Support has been found to influence involvement in various activities, while identity and importance have been shown to drive continued participation, suggesting that these factors may be of great value for encouraging and sustaining behaviour. 3. We found that, compared with White groups, multiple ethnoracial groups identified less as wildlife viewers. However, they indicated that wildlife viewing is more important to their lives. We also found that most ethnoracial groups received more support from friends, family, mentors and peers than White viewers. 4. This research can help understand the participation of Black, Indigenous and people of colour in outdoor recreation. Furthermore, this work demonstrates how legacies of racially motivated discriminatory policies may limit participation among ethnoracially diverse communities.
Gape-limited invasive predator frequently kills avian prey that are too large to swallow
Kastner, Martin; Goetz, Scott M.; Baker, Kayla M.; Siers, Shane R.; Paxton, Eben H.; Nafus, Melia G.; Rogers, Haldre S. (Wiley, 2024-07-25)
Gape-limited predators (e.g., snakes, many fish) are not generally expected to pose a predation threat to prey that are too large for them to swallow. However, the extent to which snakes predate on prey that exceed their gape limitation remains largely unknown. We conducted the first study to investigate the influence of both prey and predator sizes on the frequency of ingestion success by snakes in a natural system. We combined survival monitoring of an avian prey species (Aplonis opaca) via radio-telemetry with a survey of the size distribution of their major predator (Boiga irregularis) on Guam. This allowed us to assess (1) the frequency of unsuccessful ingestion by the predator, (2) whether the size of the prey predicts ingestion success, (3) whether the size of the predator predicts ingestion success, and (4) the relationship between prey and predator sizes in successful ingestion attempts. We found that nearly half (47.95%) of ingestion attempts by snakes on fledgling birds were unsuccessful, and no instances where unsuccessful ingestion caused the mortality of the snake. Attempts to consume smaller fledglings were as likely to be unsuccessful as attempts to swallow larger fledglings. However, snakes that successfully ingested fledglings were among the largest snakes in the population, and larger than average conspecifics attracted to endothermic prey. The smallest snakes that successfully ingested fledglings attained remarkably high relative prey mass values for their species, consuming prey weighing up to 79.9% of their own mass. Our study indicates that B. irregularis routinely predate prey that are too large for them to successfully ingest, which causes mortality to the prey but poses little risk to the predator. The potential reward for snakes in consuming oversized prey may outweigh the inherent risks, while instances of predation that do not result in consumption may have considerable impacts on prey populations.
Migratory Ecology of Pseudoplatystoma fasciatum in the Amazon Basin Revealed by Otolith Microchemistry
Pereira, Luciana A.; Castello, Leandro; Hallerman, Eric M.; Orth, Donald J.; Duponchelle, Fabrice (MDPI, 2024-06-29)
Fish migrate for varied reasons, including to avoid predators and to access feeding, spawning, and nursery habitats, behaviors that enhance their survival and reproductive rates. However, the migratory ecology of many important fishes, especially those in river–floodplain ecosystems, remains poorly understood. One fish of the Amazon Basin whose migratory behavior is poorly understood is the catfish Pseudoplatystoma fasciatum. Here, we used otolith elemental microchemistry to characterize the migration ecology of P. fasciatum in the Amazon Basin. The main research questions of this study were: (1) does P. fasciatum move between waters with different Sr isotopic signatures (⁸⁷Sr/⁸⁶Sr) and chemical compositions? (2) What distance do they migrate? (3) Is the migration of P. fasciatum related to age? And (4) does P. fasciatum migrate mainly upstream, downstream, or in both directions? We assessed whether P. fasciatum migrates between waters with different ⁸⁷Sr/⁸⁶Sr values, comparing the Sr isotopic signature of otolith transects of each individual with the range of Sr isotopic signatures within the respective rivers. We found that 34% of the 71 fish analyzed migrated between rivers with different Sr isotopic signatures and 66% did not. The mean migration distance migrated was 126 km, with most specimens migrating between 72 and 237 km. Apparently, no fish of age one or age six or older migrated. All fish that migrated were between two and five years of age, with 20% of the specimens that migrated being two years old, 40% three years old, 30% four years old, and 20% five years old. Sixty-six percent of all individuals that migrated between rivers with different Sr signatures did so bidirectionally, while 33% moved unidirectionally. According to our definition of homing behavior in which fish migrated back to the same river where they were born, 41% of all fish that migrated displayed apparent homing behavior. Our findings provide insights into the migratory ecology of P. fasciatum, corroborating and refining knowledge reported in the literature. Our results on the migratory ecology of P. fasciatum have implications for sustainable fisheries conservation and management: conserving P. fasciatum requires habitat maintenance and suitable fishing practices in spawning and nursery habitats, and managers must consider large geographic areas for effective fishery management and conservation.

Browse

Recent Submissions