Using species population structure to assist in management and decision-making in the fight against invasive species: The case of the Atlantic blue crab Callinectes sapidus

The blue crab Callinectes sapidus Rathbun, 1896 is an invasive species in the Mediterranean, with a remarkable ability to adapt to various habitats, and thereby having significant impacts on biodiversity and artisanal fishing activities. Currently, fishing is a measure being considered to control blue crab populations in invaded sites. However, it is necessary to understand the temporal structure of blue crab populations (e.g., growth, reproduction, sexual maturity) to determine specific periods when control measures need to be implemented. Considering the species' ability to adapt to various habitats, it is crucial to evaluate how temperature and salinity influence population structure. In this study, we present fishers-dependent monitoring on the temporal population structure of blue crabs in two lagoons in Corsica (France) over 12 months. Through this approach, we provide new information that can assist in decision-making for the implementation of control measures. Even though these two lagoons are geographically close, blue crab populations showed differences, particularly in terms of sexual maturity. Specimens from Biguglia mature later (males: 16.16 cm; females: 16.79 cm) than those in the Palo Lagoon (males: 14.38 cm; females: 13.86 cm). Seasonal size distribution also showed differences between the lagoons and within the same lagoon between males and females. Temperature and salinity had a significant effect on the monthly relationship between carapace width and wet weight (referred to here as growth rate) for males and females and between the lagoons. In the Biguglia Lagoon, the higher the temperature, the greater the growth rate over a wide salinity window (16–30 psu); for females, the environmental window was restricted (temperature: 20–30°C; salinities > 16 psu). The dynamics differed in the Palo Lagoon, with a more restricted high growth rate window for males, and females showed a much wider window, with high growth rates over the entire temperature and salinity range. By employing blue crab’s populations monitoring along with environmental parameters, we were able to determine how the environment influenced the blue crab’s population structure, thus identifying periods conducive to species control. The most effective strategy would undoubtedly be to eliminate females before their period of sexual maturity and copulation ensue. In our case, this would involve intensive control in summer for Biguglia and in spring for Palo. These recommendations have been translated into operations to be implemented as part of the "Territorial Plan for Combating the Blue Crab (Callinectes sapidus) in Corsica (2024–2027)"

Metabolic scaling of an invasive mussel depends on temperature and chemical cues from an invasive predator

Metabolism drives various biological processes, potentially influencing the ecological success and evolutionary fitness of species. Understanding diverse metabolic rates is fundamental in biology. Mechanisms underlying adaptation to factors like temperature and predation pressure remain unclear. Our study explored the role of temperature and predation pressure in shaping the metabolic scaling of an invasive mussel species (Brachidontes pharaonis). Specifically, we performed laboratory-based experiments to assess the effects of phenotypic plasticity on the metabolic scaling by exposing the mussels to water conditions with and without predator cues from another invasive species (the blue crab, Callinectes sapidus) across various temperature regimes. We found that temperature effects on metabolic scaling of the invasive mussels are mediated by the presence of chemical cues of an invasive predator, the blue crab. Investigating temperature-predator interactions underscores the importance of studying the ecological effects of global warming. Our research advances our understanding of how environmental factors jointly impact physiological processes

An interdisciplinary assessment of the impact of invasive gelatinous zooplankton in a French Mediterranean lagoon

International audienc

Refugia area for the ctenophore Mnemiopsis leidyi A. Agassiz 1865 in the Berre Lagoon (southeast France) : the key to its persistence

The invasive ctenophore, Mnemiopsis leidyi has been proliferating in lagoons and coastal areas around Europe for almost 20 years but the role and the impact of its presence in sink ecosystems is still not completely understood. In France, Mnemiopsis leidyi is present in Mediterranean lagoons and estuaries along La Manche Sea. Mnemiopsis was first recorded in the Berre Lagoon in early 2000. This lagoon has been highly perturbated for years, with a large volume of freshwater inflow through natural rivers and a succession of large hydroelectric power plants, inducing important eutrophication. Legislation has been implemented to improve the health status of the lagoon since 1994. A long-term study was undertaken in 2010 to measure Mnemiopsis population dynamics, and to identify the main drivers of its persistence in this highly anthropogenic lagoon. In 2011 and 2012, during extreme winter conditions, populations of this ctenophore were not observed for months. Its re-appearance later in year could be linked to either a new introduction from the Mediterranean Sea or the existence of retention areas where individuals sought refugia. Following measurement of biochemical conditions (i.e. chlorophyll a), plankton biomass and Mnemiopsis populations structure (eggs, cydippid larvae/transitional phase and adult) in different areas of the lagoon, as well as the lagrangian modelling of "particles' distribution (i.e. Ichthyop), we highlighted the seasonal patterns in the population structure, the level of available carbon always above the minimal for the survival of Mnemiopsis (24 mu gC L-1) and the potential refugia area role the Vaine sub-basin could play. Populations from the Vaine sub-basin probably serve as source populations for the rest of the lagoon by advective transport in spring

Corrigendum to “Salinity tolerance of the invasive blue crab Callinectes sapidus: From global to local, a new tool for implementing management strategy” [Sci. Total Environ. vol. 954 (2024), article number: 176291] (Science of the Total Environment (2024) 954, (S0048969724064477), (10.1016/j.scitotenv.2024.176291))

The authors regret that the printed version of the above article omitted a co-author from the list of contributors to this study. The correct version of the list of authors corresponds to the one mentioned above, and the CRediT authorship contribution statement as described below

Global literature database for freshwater jellyfish research between 1880 and 2023

Freshwater jellyfish (FWJ) research has historically been hampered by several factors, including but not limited to: focus on one life cycle stage, diversity of publication languages (numerous national languages), and regional bias, with results scattered across many sources. In this database, we attempted to compile all globally available literature pieces, i.e., peer-reviewed papers, reviews, notes, book chapters, and some grey literature published between 1880 and September 2023, but excluding newspaper articles, symposium and conference contributions, theses, and dissertations. The database contains information on three FWJ genera (Astrohydra, Craspedacusta, Limnocnida) totalling 697 entries. Other, less studied, taxonomically doubtful, and/or regionally restricted FWJ, salt lake, and low-saline tolerant genera (Australomedusa, Halmomises, Keralica, Mansariella, Moerisia) were not included. This database will enable investigators to systematically and comprehensively search for published research advancing the field of FWJ