Article
Biodiversity Conservation
Pierre William Froneman
Summary: Predator diversity plays an important role in regulating predator-prey interactions. A mesocosm study conducted in a temperate southern African estuary showed that the presence of predators led to a decrease in zooplankton abundances and an increase in chlorophyll-a concentrations, consistent with the expectations of a trophic cascade. However, there were no significant differences in chlorophyll-a concentrations or zooplankton abundances between different predator treatments, suggesting that increasing predator diversity did not contribute to increased prey risk or the strength of the trophic cascade.
Article
Ecology
Lesli C. Hernandez-Mendoza, Luis Escalera-Vazquez, Daniel Arceo-Carranza
Summary: This study compares the trophic dynamics of a fish community in a mangrove ecosystem in the Mexican-Caribbean using different types of fish species as bioindicators. The results show that the feeding characteristics of fish are related to the conservation or restoration status of the mangroves and the trophic dynamics in the community.
FRONTIERS IN FORESTS AND GLOBAL CHANGE
(2022)
Article
Environmental Sciences
Evelyn Vetsis, Ioanna Kalantzi, Spiros A. Pergantis, Lambros Kokokiris, Ioannis Karakassis
Summary: A study investigated the concentrations of 27 metals and elements in the tissues of 28 demersal and pelagic marine fish species from the Eastern Mediterranean Sea. The research found that the majority of elements had higher accumulation concentrations in the gills, liver, and scales, while the muscle had the lowest. Pelagic fish tended to accumulate higher concentrations of elements compared to demersal fish.
MARINE POLLUTION BULLETIN
(2021)
Article
Ecology
Ruijie Shen, Xiaohong Gu, Huihui Chen, Zhigang Mao, Qingfei Zeng, Erik Jeppesen
Summary: The study found that silver carp primarily stimulated phytoplankton growth by reducing zooplankton grazing rather than through nutrient recycling, resulting in higher phytoplankton biomass when silver carp is present.
FRESHWATER BIOLOGY
(2021)
Article
Environmental Sciences
Louise Day, Anik Brind'Amour, Pierre Cresson, Bastien Chouquet, Herve Le Bris
Summary: Different habitats in estuarine nurseries contribute differently to juvenile fish feeding, with species like whiting, sea bass, plaice and common sole using both intertidal and subtidal grounds for foraging. The study reveals a lack of preference for specific habitats at the community scale, as the juvenile fish use habitats simultaneously or asynchronously throughout the year. Intertidal mudflats are found to be crucial feeding grounds, especially for sea bass and common sole, contributing significantly to their diet.
ESTUARIES AND COASTS
(2021)
Article
Environmental Sciences
Bethany L. Williams, Patrick M. O'Donnell, Matthew S. Kendall, Arliss J. Winship, Brita Jessen
Summary: Changes in freshwater flow can affect estuaries and fish populations. In southwest Florida, historical manipulation of freshwater flow has occurred due to development. This study used a trawl dataset to examine the relationship between environmental variables and fish populations in three sub-estuaries. The results suggest that temporal factors were more closely related to fish populations than changes in freshwater flow.
ESTUARIES AND COASTS
(2023)
Article
Multidisciplinary Sciences
Jeremy Denis, Khalef Rabhi, Francois Le Loc'h, Frida Ben Rais Lasram, Kevin Boutin, Maria Kazour, Mamadou Diop, Marie-Christine Gruselle, Rachid Amara
Summary: This study characterizes and compares the feeding ecology of European eels in different salinity gradients in northern France estuaries. The research finds that eels mainly feed on crustaceans and fish, and their trophic level varies among different estuaries. The results are important for understanding the ecology and environmental adaptability of eels.
Article
Engineering, Marine
Jeffrey W. Short, Christine M. Voss, Maria L. Vozzo, Vincent Guillory, Harold J. Geiger, James C. Haney, Charles H. Peterson
Summary: The 2010 Deepwater Horizon blowout led to an unprecedented recruitment of Gulf menhaden, resulting in increased competition among the fish due to the loss of their predator species. This led to poor physiological conditions and low lipid content, particularly in areas with high recruitment. Trophodynamic comparisons showed the dominant role of Gulf menhaden in the food web, with implications of a trophic cascade and negative impacts on predators. Incorporating such cascading effects in damage assessment models can improve predictions and recovery strategies for major oil spills.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Ecology
Willem Bonnaffe, Alain Danet, Stephane Legendre, Eric Edeline
Summary: The study finds that the effects of temperature on food web structure depend on different levels of biological organization, leading to complex changes in network structure and functioning with warming.
Article
Fisheries
Kay Khine Soe, Siriporn Pradit, Sukree Hajisamae
Summary: Understanding trophic relationships of fish in estuarine ecosystem is crucial for sustainable resource management. This study investigated the feeding habits and trophic guilds of 29 dominant fish species at the mouth of Pattani Bay, Thailand, revealing that some species maintained consistent dietary preferences throughout the year while others showed seasonal changes.
JOURNAL OF FISH BIOLOGY
(2021)
Editorial Material
Ecology
Alan Whitfield
Summary: Baker & Sheaves criticize the Whitfield review for suggesting high predation pressure on juvenile fish in shallow estuarine nursery habitats, while research in South Africa supports the idea that shallow littoral areas provide refuge for small juveniles. More targeted research is needed to confirm the role of littoral estuarine waters as a universal keystone attribute.
MARINE ECOLOGY PROGRESS SERIES
(2021)
Article
Biodiversity Conservation
Peiyu Zhang, Huan Zhang, Huan Wang, Sabine Hilt, Chao Li, Chen Yu, Min Zhang, Jun Xu
Summary: The study provides experimental evidence for a warming-induced regime shift from clear-water conditions dominated by submerged or floating/floating-leaved macrophytes to a turbid state in shallow aquatic ecosystems. It emphasizes the importance of reducing benthivorous fish abundance for the management of shallow lakes under global climate change.
JOURNAL OF APPLIED ECOLOGY
(2022)
Article
Ecology
Maria del Mar Palacios, Mark I. McCormick
Summary: Top-predator cues indirectly influenced the behavior and survival of juvenile fish prey by reducing visits and foraging attacks from mesopredators. The predation risk from top-predators promoted risk-averse behavior in mesopredators, favoring the survival and behavior of juvenile fishes. This study highlights the cascading effects of risk through the food web and the impact of harvesting top-predators on bottom prey populations.
Article
Environmental Sciences
Karl F. W. Foley, Daniel Barnett, Deborah A. Cory-Slechta, Houhui Xia
Summary: Arsenic is a well-established carcinogen that can increase mortality, but its effects on the central nervous system, especially in early development, are not well understood. Research shows that exposure to arsenic early in life is associated with learning deficits and behavioral changes, affecting synaptic transmission and plasticity in the hippocampus.
Article
Biochemistry & Molecular Biology
Alexis J. Khursigara, Kerri Lynn Ackerly, Andrew J. Esbaugh
Summary: Crude oil and PAHs induce sub-lethal effects in early life stage fishes. It was previously believed that 3-ring PAHs drive cardiotoxicity, but recent studies have suggested that neurological impairments may not be linked to cardiotoxicity. In this study, embryonic red drum were exposed to different PAHs and it was found that 4-ring PAHs are responsible for malformations in developing red drum, indicating that oil-induced impairments in this species are not solely a result of 3-ring PAH induced cardiac malformations.
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY C-TOXICOLOGY & PHARMACOLOGY
(2022)
Article
Oceanography
Margaux Noyon, Alex J. Poulton, Sarah Asdar, Riaan Weitz, Sarah L. C. Giering
Summary: The Agulhas Bank near southern Africa plays a crucial role in the success of commercially valuable fish species, but little is known about zooplankton distribution in this area. A survey conducted in March 2019 revealed a clear gradient of mesozooplankton abundance and biovolume from inner to outer shelf areas. The Central Agulhas Bank was dominated by copepods and doliolids, with high biomass and deep mixed layer depth.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Oceanography
Sarah Asdar, Zoe L. Jacobs, Ekaterina Popova, Margaux Noyon, Warwick H. Sauer, Michael J. Roberts
Summary: Climate change poses significant threats to the Agulhas Bank fishery, particularly the chokka squid fishery. Our simulations show that increased sea surface temperature and current velocity may pose risks to squid recruitment and growth, while food availability is expected to have a minor impact.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Biochemistry & Molecular Biology
Tatenda Dalu, Ross N. Cuthbert, Ryan J. Wasserman
Summary: This study assessed plankton diversity patterns in three temporary wetland systems during winter inundation periods. The results showed that plankton community structure did not significantly differ over time or among wetlands, and hydroperiod phases did not have any significant influence on plankton taxa richness. The study highlights the seasonally distinct community succession dynamics in temporary wetlands characterized by both summer and winter inundation events.
CHEMISTRY AND ECOLOGY
(2022)
Article
Biochemistry & Molecular Biology
Tatenda Dalu, Ross N. Cuthbert, Lufuno Makhuvha, Farai Dondofema, Ryan J. Wasserman
Summary: This study investigated spatial and temporal changes in organic matter sources in sediments within the Nylsvley Wetland, South Africa and identified the contributors to sediment organic matter. The results showed uneven distribution of organic matter in the wetland, with variations in nutrient concentrations across different seasons and wetland zones. Autochthonous plants were found to be the main sources of organic matter in sediments.
CHEMISTRY AND ECOLOGY
(2022)
Article
Biodiversity Conservation
Chad Keates, Werner Conradie, Tatenda Dalu, Farai Dondofema, Eddie S. Riddel, Ryan J. Wasserman
Summary: Lycodonomorphus is a genus of lamprophiid water snake endemic to Africa. Despite being widespread and ecologically important, there is limited understanding of the genus taxonomically and phylogenetically. This study sequenced Lycodonomorphus obscuriventris, providing insights into its evolutionary relationships within the genus and challenging its original taxonomic placement.
Article
Biodiversity Conservation
Pierre William Froneman
Summary: Predator diversity plays an important role in regulating predator-prey interactions. A mesocosm study conducted in a temperate southern African estuary showed that the presence of predators led to a decrease in zooplankton abundances and an increase in chlorophyll-a concentrations, consistent with the expectations of a trophic cascade. However, there were no significant differences in chlorophyll-a concentrations or zooplankton abundances between different predator treatments, suggesting that increasing predator diversity did not contribute to increased prey risk or the strength of the trophic cascade.
Article
Marine & Freshwater Biology
L. Mofu, T. Dalu, R. J. Wasserman, D. J. Woodford, O. L. F. Weyl
Summary: The age and growth of Oreochromis mossambicus from the Sundays River Valley irrigation pond in South Africa were determined. Mark recapture of chemically-tagged fish confirmed the periodicity of growth zone creation. It was found that O. mossambicus in this warm temperate pond had relatively long life spans compared to other populations.
AFRICAN JOURNAL OF AQUATIC SCIENCE
(2023)
Article
Ecology
Ryan J. Wasserman, Tatenda Dalu
Summary: Large herbivores, such as elephants and hippopotamus, have the potential to significantly alter the limnological properties and functional role of aquatic habitats in arid and semi-arid African landscapes, despite being underexplored. This study discusses hypothetical means and known ways by which these mega-herbivores can alter shallow freshwater bodies, providing an overview of their potential influence on primary and secondary productivity.
AFRICAN JOURNAL OF ECOLOGY
(2023)
Article
Ecology
Ryan J. Wasserman, Farai Dondofema, Chad Keates, Ross N. Cuthbert, Tatenda Dalu
Article
Environmental Sciences
Kevin C. K. Ma, Jonathan R. Monsinjon, P. William Froneman, Christopher D. McQuaid
Summary: Environmental filtering (EF) can have direct and indirect effects on population dynamics, especially at range edges. We found that thermal stress gradient affects the distribution, abundance, size, and epibiont load of invasive mussel populations.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Biodiversity Conservation
Pierre William Froneman
Summary: Global climate change will cause changes in salinity regimes in southern African estuaries, which can be attributed to increased occurrences of extreme weather events and rising sea levels. This study investigated the impact of salinity on the egg production rate of the sac-spawning copepod Pseudodiaptomus hessei in a temporarily open/closed estuary. The results suggest that changing salinity due to climate warming may decrease the reproductive success of P. hessei along the southeastern coastline of South Africa.
Article
Biodiversity Conservation
Alexia M. Dievart, Christopher D. McQuaid, Gerardo I. Zardi, Katy R. Nicastro, Pierre W. Froneman
Summary: Mussel beds provide thermal buffering and can be colonized by photoautotrophic euendoliths, which indirectly benefit associated molluscs by increasing shell albedo. This study investigated the effect of euendolithic infestation on body temperatures of four mollusc species in artificial mussel beds. Results showed that non-infested beds had higher shell temperatures for two species under high solar irradiance and low wind speeds. Morphological differences between species could explain this contrast. The findings suggest that euendolithic infestation improves humidity and temperature in mussel beds, benefiting associated molluscs particularly under heat stress.
Article
Ecology
Arsalan Emami-Khoyi, Candice M. Jooste, Ryan J. Wasserman, Tatenda Dalu, Morgan J. J. Raath-Kruger, Bettine Jansen van Vuuren, Peter R. Teske
Summary: This study investigated the spatial genetic structure and dispersal history of a calanoid copepod species in temporary wetlands in the Eastern Cape province of South Africa. The wetland populations were highly structured across the landscape and potentially represent cryptic speciation. The dispersal history of these populations was affected by a postulated barrier, which eventually disappeared, allowing the species to spread into coastal regions.
FRESHWATER BIOLOGY
(2023)
Article
Marine & Freshwater Biology
Chipo P. Mungenge, Ryan J. Wasserman, Ross N. Cuthbert, Farai Dondofema, Tatenda Dalu
Summary: The acceleration of freshwater salinisation caused by human activities and climate change poses a significant threat to aquatic ecosystems. This study evaluated the effects of salinisation on crustacean communities in temporary wetlands in South Africa. Results showed that high salinities significantly reduced the richness and abundance of emergent hatchlings, with Spinicaudata and Ostracoda being the most sensitive taxa. This salinisation can lead to reduced recruitment, changes in predation pressures, food web structure, and functioning of these ecosystems, with implications for associated ecosystem services.
Article
Fisheries
Dumisani Khosa, Josie South, Ncumisa Y. Matam, Lubabalo Mofu, Ryan J. Wasserman, Olaf L. F. Weyl
Summary: In this study, the distribution of freshwater fishes in the Kowie River catchment was evaluated using historic fish distribution records and field survey data. Different methods were employed to collect fishes, including seine nets, fyke nets, and gill nets. The results showed a decrease in the number of native species and the presence of two new non-native species, which may have implications for the conservation and management of freshwater diversity in the catchment.
KNOWLEDGE AND MANAGEMENT OF AQUATIC ECOSYSTEMS
(2023)
