Tank Systems on Shrimp Farms Are Effective for Extension Demonstrations in Aquaculture

Numerous approaches can be implemented to carry out on-farm Extension demonstrations in aquaculture. The design and approach used are often governed by the problem or question that needs to be addressed as well as budgetary constraints within Extension programs. West Alabama is home to a unique inland marine shrimp industry that uses a low-salinity artesian groundwater source to raise shrimp. Demonstration and technology transfer have been carried out on commercial shrimp farms for nearly 20 years using low-budget on-levee tank systems operated by Extension personnel using this unique water source. On-farm tank demonstrations can be an effective tool for Extension professionals working in aquaculture, especially where unique circumstances exist

Challenges Experienced by Aquaponic Hobbyists, Producers, and Educators

We used an online survey to document challenges experienced by aquaponic hobbyists (n = 81), producers (n = 117), and educators (n = 75). Responses were distilled into the following categories: 1) operations and management; 2) facilities, location, and system design; 3) knowledge and educational resources; 4) funding; 5) economic viability; 6) plant culture; 7) marketing and distribution; 8) fish culture; 9) human factors; 10) regulations and certifications. Training and research in these areas are needed to advance the aquaponics industry

New Study Underway to Estimate the Impact of Lesser Scaup on Arkansas’ Baitfish Industry

The baitfish industry is an important economic enterprise for many aquaculture producers in Arkansas. The industry generates approximately $30 million annually in farm-gate sales of these small fish that include fathead minnows, goldfish and golden shiners. Diving ducks known as scaup, or “Bluebills,” spend late fall through early spring in Arkansas and Mississippi on deep water wetlands, rivers, and aquaculture ponds. The notion that scaup are consuming an abundance of baitfish in Arkansas ponds has concerned commercial growers for several years

New Study Underway to Estimate the Impact of Lesser Scaup on Arkansas’ Baitfish Industry

The baitfish industry is an important economic enterprise for many aquaculture producers in Arkansas. The industry generates approximately $30 million annually in farm-gate sales of these small fish that include fathead minnows, goldfish and golden shiners. Diving ducks known as scaup, or “Bluebills,” spend late fall through early spring in Arkansas and Mississippi on deep water wetlands, rivers, and aquaculture ponds. The notion that scaup are consuming an abundance of baitfish in Arkansas ponds has concerned commercial growers for several years

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

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

Dapagliflozin enhances fat oxidation and ketone production in patients with type 2 diabetes

OBJECTIVE Insulin resistance is associatedwithmitochondrial dysfunction and decreased ATP synthesis. Treatment of individuals with type 2 diabetes mellitus (T2DM) with sodium-glucose transporter 2 inhibitors (SGLT2i) improves insulin sensitivity. However, recent reports have demonstrated development of ketoacidosis in subjects with T2DM treated with SGLT2i. The current study examined the effect of improved insulin sensitivity with dapagliflozin on 1) mitochondrial ATP synthesis and 2) substrate oxidation rates and ketone production. RESEARCH DESIGN AND METHODS The study randomized 18 individuals with T2DMto dapagliflozin (n = 9) or placebo (n = 9). Before and after 2 weeks, subjects received an insulin clamp with tritiated glucose, indirect calorimetry, and muscle biopsies. RESULTS Dapagliflozin reduced fasting plasma glucose (167 ± 13 to 128 ± 6 mg/dL) and increased insulin-stimulated glucose disposal by 36% (P < 0.01). Glucose oxidation decreased (1.06 to 0.80 mg/kg · min, P < 0.05), whereas nonoxidative glucose disposal (glycogen synthesis) increased (2.74 to 4.74 mg/kg · min, P = 0.03). Dapagliflozin decreased basal glucose oxidation and increased lipid oxidation and plasma ketone concentration (0.05 to 0.19 mmol/L, P < 0.01) in association with an increase in fasting plasma glucagon (77 ± 8 to 94 ± 13, P < 0.01). Dapagliflozin reduced the ATP synthesis rate, which correlated with an increase in plasma ketone concentration. CONCLUSIONS Dapagliflozin improved insulin sensitivity and caused a shift from glucose to lipid oxidation, which, together with an increase in glucagon-to-insulin ratio, provide the metabolic basis for increased ketone production

Less talk, more action: (Re)Organising universities in Aotearoa, New Zealand

Despite the growing size of the academic precariat in the tertiary sector, this exploited group of workers lacks a voice in either their universities or their national union. In this article we draw on our experiences of transitioning from a small activist group to a broader research collective with influence and voice, while forging networks of solidarity. Through reflecting on developing the Precarious Academic Work Survey (PAWS), we explore how action research is a viable way of structurally and politically (re)organising academic work. We argue that partnering with changemakers such as unions as co-researchers disrupts their embedded processes so that they may be (re)politicised towards pressing issues such as precarity. Further, we highlight how research can be used as a call to action and a tool to recruit powerful allies to collaborate on transforming universities into educational utopias