Predicting optimal combinations of by‐catch reduction devices in trawl gears: A meta‐analytical approach

Global efforts to reduce unwanted catches have led to the development of a vast array of by‐catch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta‐analytical approach that combines the data available on BRDs tested independently in a fishery and predict the theoretical selectivity of all possible combinations of those devices. This allows to identify promising BRD combinations, worth experimental investigation and flexible trawl configurations, where the selectivity can be substantially modified by adding or removing one BRD, thus aiding fishermen in adapting to high variability in catch composition and quota availability. To illustrate the approach, we used BRDs developed for the well‐studied Nephrops (Nephrops norvegicus, Nephropidae) directed mixed trawl fishery in the Skagerrak and Kattegat seas. We predicted the selectivity of 100 BRD combinations for Nephrops, cod (Gadus morhua, Gadidae) and haddock (Melanogrammus aeglefinus, Gadidae), compared them in terms of absolute selectivity and performance under realistic catch scenarios, from both single‐ and multispecies perspectives, and identified 15 BRD combinations that could be worth future experimental investigation. The meta‐analytical approach makes best use of existing knowledge and leads to new insights about the potential for improvement and flexibility in trawl selectivity. This could benefit a variety of mixed trawl fisheries and help developing a new generation of more flexible gears, with multiple BRDs integrated in their structure.     

Serological diversity in Flavobacterium psychrophilum: A critical update using isolates retrieved from Chilean salmon farms

Chile is currently the second largest producer of farmed salmon worldwide, but Flavobacterium psychrophilum, as one of the most detrimental pathogens, is responsible for major losses during the freshwater culturing step in salmonid fish farms. An antigenic study conducted 10 years ago reported four serological groups using 20 F. psychrophilum Chilean strains. To reduce disease outbreaks and to develop vaccine candidates, antigenic knowledge needs to be regularly updated using a significant number of additional recent F. psychrophilum isolates. The present study aimed at investigating the serological diversity of 118 F. psychrophilum isolates collected between 2006 and 2018 from farmed Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch). The current study supports an expansion of the known antigenic groups in Chile from 4 to 14. However, the use of the slide-agglutination technique for serotyping is costly, is labour-intensive and requires significant technical expertise. Addressing these points, the mPCR-based procedure was a very useful tool for serotyping the collected Chilean F. psychrophilum isolates. This technique revealed the presence of diverse mPCR serotypes (i.e. types 0, 1, 2 and 4). Therefore, mPCR should be employed to select the bacterial strain(s) for vaccine development and to conduct follow-up, selective breeding or epidemiological surveillance in Chilean fish farms. Given the presented findings, changes to Chilean fish-farming practices are vital for ensuring the continued productivity and well-being of farmed salmonids.     

Filling the gaps in the Argentinian distribution of orthohantavirus: First finding of Lechiguanas virus in rodents from Corrientes,Argentina

Hantavirus Pulmonary Syndrome (HPS) is an emerging infectious disease caused by orthohantaviruses in the Americas. In Argentina, since 1995, several reservoirs and virus variants have been described, but the northeastern and central endemic zones in the country include an area without human or rodent infections, despite sharing rodent species with areas with that disease. The aim of this study was to search for orthohantavirus in rodent communities that inhabit this area, which borders two endemic areas of HPS. Small rodents were captured in June of 2022 through a total effort of 644 trap nights distributed in five grids located in the Iberá National Park, Corrientes, Northeastern Argentina. All rodents were sexed, weighed, and the species was recorded. Blood samples were extracted to detect ANDV-specific immunoglobulin G (IgG), and to extract the RNA virus. Trimmed sequences were mapped against reference sequences from GenBank. We captured a total of 36 Oligoryzomys flavescens and 15 Oxymycterus rufus. We detected the O. flavescens species infected with Lechiguanas orthohantavirus in the camping area of the National Park. A nucleotide comparison with previously published sequences shows a 98.34% similarity to the virus obtained from a human case of HPS reported in the adjacent Misiones province. This study demonstrated, for the first time, that O. flavescens is a host of the Lechiguanas orthohantavirus in this zone and contributes to closing information gaps on the distribution of orthohantavirus in Argentina. Additionally, the high similarity with the hantavirus found in the human case of Misiones suggests that the reservoir in that province would also be O. flavescens (not previously confirmed). This information permits us to focus on the preventive measurements to protect the human population.     

Forest cover and landscape heterogeneity shape ant–plant co-occurrence networks in human-dominated tropical rainforests

Landscape Ecology - The effects of habitat loss and fragmentation on biodiversity involve a series of mechanisms and processes that cannot be studied in isolation, mainly because human-modified...     

Improvement of soybean cultivars for natto production through the selection of seed morphological and physiological characteristics and seed compositions: A review

Natto, a traditional soyfood fermented by Bacillus subtilis (natto), is prepared by steaming/cooking of soaked soybean seeds followed by inoculation with the bacteria and incubation. Natto soybean has increased in popularity due to its nutritional value and health benefits. Thus, the natto soybean market provides additional opportunities for farmers. The development of soybean cultivars with improved natto quality characteristics is crucial for maintaining and increasing the natto soybean market. Good‐quality characteristics of natto are determined by soybean cultivar, processing conditions and bacteria strain. Natto quality evaluation generally determined by sensory panels is time consuming. Therefore, indirect selection for natto quality based on seed traits is preferred. Seed morphological and physiological characteristics and seed compositions play an important role in producing natto of good quality. In this review, we have summarized natto processing conditions, natto quality characteristics, seed traits involved in natto quality and their genetic variation, as well as the genetic diversity in food‐grade soybean germplasms and B. subtilis strains. Information presented will be helpful for natto soybean cultivar development and natto manufacture.