Food habits of wintering double-crested cormorants in the Mississippi Delta

Given its ubiquity, it is not surprising that agriculture, including fin fish aquaculture, contributes to food webs worldwide and is used by numerous wildlife for foraging and meeting other needs. Double-crested Cormorants (Phalacrocorax auritus) impact United States commercial aquaculture and are considered the primary avian predator in catfish (Ictalurus spp.) aquaculture facilities in the Mississippi Delta. Recent changes in aquaculture practices, regulatory policies, and decreased overall hectares in production prompted this study that assessed cormorant consumption of catfish in relation to their night roosts through surveys and diet analysis. Cormorants were collected from night roosts from October through April 2016–2018 (n=69 collections). On average, catfish constituted 33% of a cormorant\u27s overall diet, which is less than reported in previous studies. There was no statistical difference between consumption of channel (I. punctatus) and hybrid catfish (I. punctatus x I. furcatus) based on biomass estimates, and the greatest consumption of catfish occurred in the months of February and March. The best fit model for predicting catfish consumption was the cubic polynomial function of the area of catfish aquaculture within a 30.6 km forage buffer of a night roost. Our findings will inform wildlife managers about relationships between cormorant night roost locations and consumption of catfish and aid decision making with respect to cormorant management. Despite cormorants having shifted consumption to naturally occurring fish species associated with changes to aquaculture, aquaculture remains an important part of regional food webs

Depredation Impact of Double-Crested Cormorants (Phalacrocorax auritus) on Commercial Catfish Production in the Mississippi Delta

Double-crested Cormorants (Phalacrocorax auritus) impact United States commercial aquaculture and are considered the greatest avian predators on catfish (Ictalurus spp.) aquaculture facilities. Cormorants are especially problematic in the Delta region in western Mississippi, where catfish production is concentrated providing ideal wintering and foraging areas. Although cormorant/aquaculture dynamics have been studied, recent changes in aquaculture practices, regulatory policies, and decreased overall hectares in production merit contemporary research. Therefore, we estimated abundance and distribution of cormorants at their night roosts and assessed diet related to catfish consumption. Aerial surveys of cormorant night roosts were flown from October through April, 2016-2018. Following each survey, three active night roosts were randomly selected for harvesting cormorants for later necropsy and stomach contents assessment. We completed 25 total surveys and counted an average of 23,379 cormorants (range 5,026 to 40,535) pooled over years (corrected for observer and method bias). A total of 728 cormorants from 27 different night roosts were collected across years. Survey count models estimated 4.2 and 5 million cormorant forage days in the Delta during winters 2016-2017 and 2017-2018, respectively. Throughout the study, catfish comprised 33% of the prey biomass detected; shad (Dorosoma spp.) also were dominant (58%) prey. Evidence suggests that the area of catfish aquaculture surrounding a night roost within a 30.6-km forage buffer is an important predictor for a bird’s relative amount of catfish consumption. These results will inform wildlife managers regarding relationships between cormorant night roost locations in the Delta and disproportionate consumption of catfish, enhancing techniques to reduce fish losses on aquaculture facilities

Scaup Depredation on Arkansas Baitfish and Sportfish Aquaculture

Lesser scaup (Aythya affinis) and greater scaup (A. marila), hereafter scaup, consume a variety of aquatic invertebrates, plants, and occasionally small fish. Scaup have foraged on commercial aquaculture farms in the southern United States for decades. However, the types, abundance, and rate of fish exploitation by scaup on baitfish and sportfish farms are not well documented. Thus, information is needed to understand how fish and other foods influence scaup use of aquatic resources, and any potential economic effects of depredation of fish. From November–March in winters 2016–2017 and 2017–2018, we conducted 1,458 pond surveys to estimate the abundance and distribution of scaup on Arkansas baitfish and sportfish farms that commercially produce species such as golden shiners (Notemigonus crysoleucas), fathead minnows (Pimephales promelas), goldfish (Carassius auratus), and sunfish (Lepomis spp.). We also collected and processed 531 foraging scaup and quantified the proportion of scaup consuming fish and the proportion of their diet obtained from fish. Fish consumption was highly variable between years. In our survey area, we estimated total fish consumption at 1,400 kg and 60,500 kg for winters 2016–2017 and 2017–2018, respectively. Sunfish ponds experienced the maximum loss (18,000 fish/ha) during winter 2017–2018, while goldfish ponds experienced a loss of just 2,600 fish/ha during the same winter. The estimates of baitfish and sportfish loss to scaup revealed potential management strategies for minimizing fish loss and can inform economic analysis of the financial impact of scaup on producers

Foraging Ecology and Distribution of Scaup (Aythya spp.) on Arkansas Commercial Baitfish and Sportfish Farms

Lesser Scaup (Aythya affinis)and Greater Scaup (Aythya marila) have been reported to consume substantial quantities of golden shiners (Notemigonus crysoleucas), fathead minnows (Pimephales promelas), goldfish (Carassius auratus), and sunfish (Lepomis spp.) produced on Arkansas commercial baitfish and sportfish farms. The goals of this study were to investigate foraging ecology and distribution of Scaup at these facilities, and use this information to assist producers in administering bird harassment efforts more efficiently. During typical wintering period for Scaup in Arkansas (November-March), we conducted approximately 1,400 pond surveys to estimate abundance and distribution of scaup on farms in 2016-2017 and 2017-2018. Information related to pond size, fish species, fish size, and stocking density, were also obtained to enable a more detailed analysis of Scaup use. We also collected 561 Scaup from these facilities to quantify the proportion of diet obtained from fish. There was an increase in Scaup abundance and fish consumption between the first to the second winter, likely attributed to cooler temperatures during the second winter. Our distribution model predicted an increased probability of Scaup use on larger ponds containing high densities of fish, while diet analysis indicated increased fish consumption during colder winter periods. Our results can be used by farm managers to designate resources for bird harassment to particular locations and times of the winter when scaup are more likely to negatively impact the fish crop

Transplanting embryonic stem cells onto damaged human corneal endothelium

AIM To investigate whether human embryonic stem cells (hESCs) could be made to attach, grow and differentiate on a human Descemet’s membrane (DM). METHODS Spontaneously differentiated hESCs were transferred onto a human corneal button with the endothelial layer removed using ocular sticks. The cells were cultured on a DM for up to 15 d. The genetically engineered hESC line expressed green fluorescent protein, which facilitated identification during the culture experiments, tissue preparation, and analysis. To detect any differentiation into human corneal endothelial-like cells, we analysed the transplanted cells by immunohistochemistry using specific antibodies. RESULTS We found transplanted cells form a single layer of cells with a hexagonal shape in the periphery of the DM. The majority of the cells were negative for octamer-binding transcription factor 4 but positive for paired box 6 protein, sodium potassium adenosine triphosphatase (NaKATPase), and Zona Occludens protein 1. In four of the 18 trials, the transplanted cells were found to express CK3, which indicates that the stem cells differentiated into corneal epithelial cells in these cases. CONCLUSION It is possible to get cells originating from hESCs to become established on a human DM, where they grow and differentiate into corneal endothelial-like cells in vitro.De Blindas Vänner, Gothenburg, and Greta Bergs Foundation, Lerum (to Charles Hanson); University of Akureyri Research Fund, the KEA Fund, and the Icelandic Council on Ageing (to Arsaell Arnarsson); and Gothenburg Medical Society, the Medical Faculty of the University of Gothenburg and the Herman Svensson Foundation (to Ulf Stenevi)Peer Reviewe

Binational reflections on pathways to groundwater security in the Mexico-United States borderlands

Shared groundwater resources between Mexico and the United States are facing unprecedented stressors. We reflect on how to improve water security for groundwater systems in the border region. Our reflection begins with the state of groundwater knowledge, and the challenges groundwater resources face from a physical, societal and institutional perspective. We conclude that the extent of ongoing cooperation frameworks, joint and remaining research efforts, from which alternative strategies can emerge, still need to be developed. The way forward offers a variety of cooperation models as the future offers rather complex, shared and multidisciplinary water challenges to the Mexico–US borderlands

Binational reflections on pathways to groundwater security in the Mexico–United States borderlands

Shared groundwater resources between Mexico and the United States are facing unprecedented stressors. We reflect on how to improve water security for groundwater systems in the border region. Our reflection begins with the state of groundwater knowledge, and the challenges groundwater resources face from a physical, societal and institutional perspective. We conclude that the extent of ongoing cooperation frameworks, joint and remaining research efforts, from which alternative strategies can emerge, still need to be developed. The way forward offers a variety of cooperation models as the future offers rather complex, shared and multidisciplinary water challenges to the Mexico–US borderlands

Level and determinants of county health system technical efficiency in Kenya: two stage data envelopment analysis.

BACKGROUND: Improving health system efficiency is a key strategy to increase health system performance and accelerate progress towards Universal Health Coverage. In 2013, Kenya transitioned into a devolved system of government granting county governments autonomy over budgets and priorities. We assessed the level and determinants of technical efficiency of the 47 county health systems in Kenya. METHODS: We carried out a two-stage data envelopment analysis (DEA) using Simar and Wilson's double bootstrap method using data from all the 47 counties in Kenya. In the first stage, we derived the bootstrapped DEA scores using an output orientation. We used three input variables (Public county health expenditure, Private county health expenditure, number of healthcare facilities), and one outcome variable (Disability Adjusted Life Years) using 2018 data. In the second stage, the bias corrected technical inefficiency scores were regressed against 14 exogenous factors using a bootstrapped truncated regression. RESULTS: The mean bias-corrected technical efficiency score of the 47 counties was 69.72% (95% CI 66.41-73.01%), indicating that on average, county health systems could increase their outputs by 30.28% at the same level of inputs. County technical efficiency scores ranged from 42.69% (95% CI 38.11-45.26%) to 91.99% (95% CI 83.78-98.95%). Higher HIV prevalence was associated with greater technical inefficiency of county health systems, while higher population density, county absorption of development budgets, and quality of care provided by healthcare facilities were associated with lower county health system inefficiency. CONCLUSIONS: The findings from this analysis highlight the need for county health departments to consider ways to improve the efficiency of county health systems. Approaches could include prioritizing resources to interventions that will reduce high chronic disease burden, filling structural quality gaps, implementing interventions to improve process quality, identifying the challenges to absorption rates and reforming public finance management systems to enhance their efficiency