Freshwater Biology

Patrolling males and waiting females — observing reproductive behavior of black sea bream in the wild

A smarter way to measure how streams clean themselves

A new approach using Michaelis-Menten enzyme kinetics offers a direct fix for estimating nutrient uptake length in streams. The zero-order method substantially outperforms the first-order approach under saturation, providing more accurate estimates of stream filtration capacity.

Tiny plankton have big impact on harmful algal bloom predictions

Researchers at Hiroshima University have developed a new approach to predicting harmful algal blooms by coupling three models and accounting for plankton species interactions. This improved forecasting can help prevent economic losses and protect fish stocks in countries like Chile, which has been hit hard by these blooms.

Comparative analysis of intermuscular bones in hybrid fish (BTB) and its parents

Researchers have developed a new method to reduce intermuscular bones in hybrid fish through hybridization, resulting in offspring with fewer IBs and improved processing efficiency. The study provides molecular biological insights into phenotypic changes in hybrid lineages and their derivatives.

Vital freshwater fish migrations are collapsing: UN report

Hundreds of migratory fish species are facing accelerating declines due to dam construction, habitat fragmentation, pollution, overfishing, and climate-driven ecosystem changes. The Global Assessment of Migratory Freshwater Fishes identifies 325 species needing coordinated international conservation efforts.

Stolen chloroplasts maintained by host-made proteins offer clues to plant cell origins

A single-celled predator, Rapaza viridis, retains chloroplasts from prey algae and imports host-made proteins into them, revealing deeper levels of host–organelle integration. This process may have played a role in the emergence of plant cells.

Road salt creates more harm to freshwater life than expected, study finds

Research by University of Missouri scientists found that road salt is deadly to freshwater snails when paired with the presence of predators, causing nearly 60% higher mortality rates. The study suggests practical solutions to reduce salt pollution in waterways, such as cutting road salt use by up to 50%.

Neural progesterone receptors link ovulation and sexual receptivity in medaka

Researchers found a neuroendocrine mechanism linking ovarian status to brain signals controlling sexual receptivity in female teleosts. Progesterone analogs restored sexual behavior but not ovulation, suggesting a direct neural pathway for hormone reception.

Translocating nanoplastics in zebrafish

Researchers found that nanoplastics entered the bloodstream and accumulated in organs within days of ingestion, potentially leading to disorders in nervous and reproductive systems. The particles were primarily expelled through the intestine, but some remained trapped for a long time.

Enantioselective maternal transfer of pesticide metabolite and its thyroid effects

A new study reveals that the S-enantiomer of o,p'-DDD pesticide metabolite is more toxic to zebrafish larvae and has severe consequences for their development. The research found that maternal transfer was highly efficient, with the S-enantiomer accumulating in higher levels than its mirror-image R-form.

FAU’s CAROSEL offers new ‘spin’ on monitoring water quality in real time

Researchers track benthic nutrient fluxes using a new device called CAROSEL, which measures nitrogen released from sediments in real-time. The findings reveal daily rhythms in oxygen fluxes and highlight the importance of understanding sediment-water interactions in managing aquatic ecosystems.

Microbial DNA sequencing reveals nutrient pollution and climate change reinforce lake eutrophication

A new Concordia-led study links algal blooms in Canadian lakes to both nutrient pollution from agricultural runoff and climate change. The research, using DNA sequencing of lakebed microbes, found that these two drivers amplify each other in ways that profoundly affect lake ecosystems.

Coastline of lakes an important part of global carbon cycle

New research reveals that lake littoral zones store more carbon than previously thought, highlighting the need for inclusion in global carbon budgets. By including these zones, lakes may switch from being net carbon sources to net carbon sinks.

Light up our love: Medaka courtship dynamics observed

Researchers at Osaka Metropolitan University discovered medaka reproductive behavior begins in dark period around 7 a.m. and peaks at 8 a.m., with overall behavior similar to that observed in the wild, except for a 3-4 hour delay in courtship and reproduction times compared to natural environments.

What environmental factors determine fish life history strategies in a river?

A multinational research team analyzed life history trait data for 1,613 fish species across 14 major rivers worldwide. They found significant variation in life history traits among river systems, strongly associated with key environmental variables.

Carp in recreational fisheries show high resilience to stress of capture

A new study found that domesticated carp have lower chronic stress levels than their wild counterparts, despite regular angling capture. The researchers compared scale cortisol data from domesticated and wild carp and found that the former had significantly lower levels of chronic stress.

Island rivers carve passageways through coral reefs

Research shows that island rivers shape reef passes, allowing seawater and nutrients to flow in and out. The locations of reef passes align with where rivers funnel out from an island's coast, providing circulation throughout the reef.

Low pH aggravates toxicity of polystyrene microplastics in crab Eriocheir sinensis

A study found that combined low pH and polystyrene microplastic exposure synergistically exacerbated oxidative damage and immune suppression in Chinese mitten crabs. Gut microbiota showed substantial functional alterations despite maintained alpha-diversity.

Extreme weather cycles change underwater light at Tahoe

A study by University of California, Davis' Tahoe Environmental Research Center found large fluctuations in ultraviolet radiation between wet and dry years at Lake Tahoe. UV radiation penetrates deeply in clear waters like Lake Tahoe, affecting aquatic ecosystems and photosynthesis.

Ancient poems tell the story of charismatic river porpoise’s decline over the past 1,400 years

Researchers analyzed 724 ancient Chinese poems to track the decline of the Yangtze finless porpoise's habitat range. The study found that the porpoise's range decreased by at least 65% over 1,400 years, with most of this decline occurring in the past century. This ancient art form provides a unique window into biodiversity conservation.

Flex appeal: ‘Trade-off’ between armor and efficiency in sea turtle shells

Marine turtles' shells exhibit complex trade-offs between toughness, stiffness and flexibility to protect against predators while optimizing movement. The shell's design accommodates demands of both survival and efficient locomotion in aquatic habitats.

Migrating roach have sharper eyesight

A study from Lund University found that migrating freshwater roach have larger pupils and better eyesight than non-migrating individuals. This adaptation enables them to detect small food sources in low-light conditions, crucial for survival during migration.

Biobreeding technology enables rapid development of golden Grass Carp germplasm

A study successfully uses CRISPR/Cas9 to disrupt the tyrosinase-related protein B (tyrb) gene in grass carp, resulting in the generation of red-eyed golden mutants. This innovation offers a solution to address genetic degradation and improves ornamental value and disease resistance.

Nighthawks: Wild medaka actively court female fish in wee hours

A team of researchers from Osaka Metropolitan University observed wild medaka behavior in their river habitat, discovering that they spawn around midnight. The study also found that males exhibit two types of courtship behaviors: chasing females and a display of making quick circles in front of the opposite sex.

Tracking algae species interactions to help predict harmful algae blooms

Researchers at Hiroshima University have discovered complex interactions between Pseudo-nitzschia groups and other algal species, suggesting salinity has a more significant influence than previously thought. This understanding is crucial for predicting harmful algal blooms, which cause substantial damage to the aquaculture industry.

Microbial solutions for boosting seaweed farming and carbon capture

Researchers found that manipulating seaweed's microbiome can boost its potential for fighting climate change by promoting disease resistance, nutrient uptake, and stability. Early life stages of seaweeds are critical windows for establishing beneficial microbes that persist throughout the seaweed's life cycle.

Calls to curb invasive species spread via untreated water transfer

Researchers warn of the risks of spreading invasive species via untreated water transfers, which can move between different environments. The study highlights the need for coordinated surveillance and management plans to tackle this threat and conserve freshwater biodiversity.

The potential of artificial freshwater habitats in supporting ecology of native fishes

Researchers successfully rehabilitated a decommissioned stormwater management pond, creating a habitat for 16 native fish species. The pond provided connectivity between the river and lake, allowing fish to freely move between the two, indicating potential as important spawning grounds.

New technique for investigating sense of smell in fish

Researchers have identified nine distinct cell types with unique transcriptional profiles in the olfactory epithelium of zebrafish after exposure to conspecific alarm substances. This discovery provides a valuable avenue for exploring cellular diversity and assessing genetic profiles from behavioral perspectives.

Fishy business: Male medaka mating limits revealed

A study by Osaka Metropolitan University experts found that male medaka can mate up to 19 times a day, releasing more than 50% of their daily sperm output in the first three matings. The fertilization rate decreases significantly after this point, with some cases showing no fertilization.

Peat-bog fungi produce substances that kill tuberculosis-causing bacteria

Researchers identified five fungi species with toxic effects against the bacterium, which disrupts cellular levels of thiols essential for bacterial survival. The findings support a strategy for developing treatment-shortening drugs by targeting biological processes maintaining thiol levels.

Lipidome and proteome insights into Mariana Trench snailfish adaptation to the Hadal Zone

The study reveals that the hadal snailfish has unique metabolic adjustments to store energy, optimize energy utilization, and maintain membrane fluidity. The fish increases lipid reserves, elevates CoQ and ATPase levels, and adjusts fatty acid ratios to withstand food scarcity and high pressure.

Unique biodiversity patterns in high-altitude rivers on the Qinghai-Tibetan plateau revealed

A study published in Water Biology and Security reveals spatial and temporal patterns of biodiversity in four taxonomic groups along the Za'gya Zangbo River. The findings emphasize the importance of considering multiple biological groups in biomonitoring high-altitude rivers, and highlight areas that require targeted conservation efforts.

Tire-wear particles pose health risks to aquatic organisms

Researchers discovered that tire-wear particle leachates induce hepatic oxidative stress, inflammation, and histopathology changes in black-spotted frogs. These disruptions can lead to long-term health issues for affected organisms.

Bridging large riverine ecosystems for inter-basin exchanges

A study comparing fish species in the Mississippi and Yangtze Rivers found that feeding habits and habitat preferences were key influencers of species responses to environmental conditions. The research highlights the importance of considering these factors in developing effective management strategies for large riverine ecosystems.

Simulated construction of plant-based fish meat with composite structure via 3D printing

A team of researchers from China successfully created plant-based simulated yellow croaker meat tissues using dual-nozzle 3D printing. The study found that the texture characteristics, moisture distribution, and nutrient content of the simulated fish were close to those of real fish, with a printing accuracy of over 90%.

Wild and human-cared spotted dolphins harbor different gastrointestinal microbiomes

A recent study revealed notable differences in gastrointestinal microbial communities between wild and human-cared spotted dolphins, suggesting that food source variations play a significant role. The findings highlight the importance of understanding marine mammal gut microbiomes and underscore the need for comprehensive future research.

Improvement and application of genetic resources of grass carp (Ctenopharyngodon idella)

The article reviews major research results on grass carp morphology, cytogenetics, molecular genetics, and germplasm resource genetic improvement. Key findings include the origin and geographical distribution of grass carp and its genetic improvement technology, including gynogenesis and hybridization techniques.

Australian bushfire ash is deadly for aquatic life

Research reveals wildfire ash can have devastating consequences on Australian water ecosystems, affecting both terrestrial and aquatic organisms. The study found that two common crustacean species had varying levels of sensitivity to ash concentrations, with some unable to survive even low doses.

Thirty years of change of fish communities in South China Sea

A study on fish communities in Daya Bay reveals a decline in diversity, shifts in composition, and shrinking of fish body size over the past 30 years. The research highlights the impact of environmental pollution, overfishing, and habitat fragmentation on the ecosystem.

Species composition and succession of coral reef fishes in Huaguang Reef, Xisha Islands

This study identified 299 coral reef fish species in Huaguang Reef, with Perciformes exhibiting the highest species count. Notably, a reduction in species at the order and family levels was observed compared to historical data. The succession patterns indicate a notable impact of overfishing on coral reef fishes.

Fishy parenting? Punishing offspring encourages cooperation

A study by Osaka Metropolitan University reveals that fish use physical punishment to promote helping behavior in their offspring, demonstrating advanced social and cognitive abilities. The research highlights the presence of punishment in animal societies, bridging a gap in understanding cooperative behavior and its mechanisms.

Chinese wisdom and modern innovation of aquaculture

This study introduces modern innovations in Chinese aquaculture, focusing on genetic breeding, fertility biotechnology, polyculture, eco-agriculture, smart aquaculture, and eco-engineered aquaculture. The research proposes ten paradigm changes to promote sustainable aquaculture development and global food security.

A big step for fish herpesvirus diagnostics and treatment

Researchers have established a highly permissive cell line, GiCS, from gibel carp skin tissue, offering robust tools for early detection and study of Carassius auratus herpesvirus. A novel diagnostic method utilizing droplet digital PCR allows for sensitive detection of CaHV in infected fish on the first day post-infection.

Researchers receive National Science Foundation grant for long-term data research

Virginia Tech researchers have received a five-year National Science Foundation grant to develop an open-source automated forecasting system for lakes. The system will enable real-time data collection and publishing, allowing researchers to predict water quality in lakes around the globe.

Zebrafish usp3 loss promotes hypoxic tolerance

Researchers found that zebrafish lacking usp3 exhibit enhanced hypoxic capacity due to decreased HIF-1α degradation, leading to improved tolerance. The study reveals usp3's role in modulating the activity of HIF-1α and its impact on hypoxia signaling.

Bloom-forming cyanobacteria and dinoflagellates in five Argentinian reservoirs: a multi-year sampling

Researchers in Argentina have found that cyanobacteria blooms are becoming more intense in five reservoirs, particularly in the warmest areas. The team also detected positive records of cyanotoxins only in the last four years of the study period, highlighting a significant underestimation of the problem.

Wildfires also impact aquatic ecosystems

Research from the University of California San Diego finds that wildfires transform lakes and aquatic ecosystems, storing more carbon and emitting less CO2. The study suggests a shift in the role of aquatic systems in the global carbon cycle, with potential consequences for aquatic health and fisheries.

Researchers awarded $1M to protect coastal communities, aquaculture industry

The BioSPACE project aims to provide farmers, environmental agencies, and water-reliant industries with portable sensors to rapidly detect germs that threaten marine and freshwater life. The economic burden caused by waterborne diseases exceeds $3 billion in direct health care costs each year in the United States.

Clonal fish: Same genes, same environment – different fitness levels

Researchers found that genetically identical Amazon mollies exhibit differences in offspring size and reproductive output, indicating varying levels of biological fitness. The study suggests that epigenetics, stochasticity, and micro-environmental factors play a role in the emergence of individuality.

Cladophora in Qinghai Lake as ecological engineer helps increase phytoplankton biodiversity

Researchers found Cladophora blooms increase Bacillariophytes and alter physicochemical properties, leading to shifts in phytoplankton communities and biomass. The study suggests FABs as ecological engineers influencing alpine lake ecosystems.

Unveiling the wonders of ciliate conjugation: Insights from Paramecium jenningsi

Researchers investigated ciliate conjugation in Paramecium jenningsi, uncovering a 48-hour process with three prezygotic and postzygotic divisions. The study provides new insights into nuclear selection and differentiation during meiosis.

New study finds that sewage release is worse for rivers than agriculture

Researchers found treated sewage discharge to be the best predictor of high nutrient levels and algae blooms in four English rivers, even when agricultural pollution was present. The study highlights the disproportionate impact of sewage on river quality and calls for improved regulations and waste management practices.

Do cyanobacteria make the neurotoxin β-N-methylamino-L-alanine (BMAA)?

A recent study published in Water Biology and Security challenges the hypothesis that cyanobacteria produce β-N-methylamino-L-alanine (BMAA), a non-protein amino acid linked to neurodegenerative diseases. The study found no detectable levels of BMAA in laboratory-cultured strains and natural cyanobacterial bloom samples.

Advancing coastal waterbird conservation in China: policy progress and challenges

China has made significant strides in coastal wetland conservation, with notable progress in national-level legislation and stakeholder engagement. However, pressing issues persist, including habitat restoration, invasive species control, and pollution management, which require more science-based decision-making and action.

Freshwater connectivity can transport environmental DNA through the landscape

Research finds that water movement between lakes can transport environmental DNA, making eDNA a promising tool for tracking aquatic species and monitoring biodiversity. The study highlights the importance of considering landscape connectivity when designing eDNA surveys to ensure accurate biodiversity assessments.

Stoichiometric mismatch between phytoplankton and zooplankton under climate warming and eutrophication

Research found that climate warming and eutrophication lead to divergent responses in phytoplankton and zooplankton, causing a mismatch in elemental ratios. The study discovered that the interplay of these stressors can reverse the stoichiometric imbalance.

Scientists create 3D models of freshwater mussels to help save them from extinction

Researchers are creating digital 3D models of freshwater mussels using photogrammetry, allowing biologists and conservationists to identify species and teach field biologists how to distinguish characteristics. The online course will also educate the public about these essential creatures that filter algae and stabilize streambeds.

Adapting to water temperature changes: the smart "coat" of Yangtze finless porpoise

The Yangtze finless porpoise has evolved a specialized subcutaneous blubber layer that serves as an intelligent thermal coat, regulating body temperature in response to changing water temperatures. The blubber thickness changes with the water temperature, becoming thicker in colder waters and thinner in warmer waters.

Sea urchins are struggling to ‘get a grip’ as climate change alters ecosystems

Sea urchins struggle to 'get a grip' as climate change causes lower salinity levels, affecting their ability to attach to surfaces. The study found that low salinity conditions negatively impact righting response, movement, and adhesive ability.