International Journal of Limnology

Fertilization and early development of coregonines were affected by sulfate in toxicity tests. The sulfate tolerance of brackish water forms of vendace and whitefish was higher than freshwater forms. The lethal concentrations of sulfate toxicity determined in this study provide valuable information for the construction of species sensitivity distributions, and further formulation the water quality guidelines for both brackish and freshwater environments.

There was no association between water level variables and the density of newly hatched whitefish larvae or egg survival. Neither was the average larval density in the regulated lakes generally lower than that in the non-regulated lake. Thus, moderate water level regulation does not drive whitefish population dynamics directly by negatively affecting the life stage from spawning to hatching.

Perialpine lakes face climate warming, impacting coregonine fish populations. The exposition of European whitefish embryos from perialpine populations to actual/cold and future/warm temperatures in the lab reveals strong impact on survival and incubation duration and contrasted ability of populations to cope with warming waters.

Our paper developed and evaluated temperature-dependent embryo development modelsfor a group of cold, stenothermic fishes (Salmonidae Coregoninae) to assess the potential impacts of climate-induced changes in water temperature on cisco (Coregonus artedi) from two populations in Lake Superior (Apostle Islands [USA] and Thunder Bay [Canada]) and one in Lake Ontario (USA), vendace (C. albula) in Lake Southern Konnevesi (Finland), and European whitefish (C. lavaretus) in lakes Southern Konnevesi, Constance (Germany), Geneva (France), and Annecy (France). Water temperatures for each study group were simulated and changes in reproductive phenology across historic (1900-2006) and three future climatic-warming scenarios (2007-2099) were investigated. Models predicted that increases in water temperatures are likely to cause delayed spawning, shorter embryo incubation durations, and earlier larval hatching. Relative changes increased as warming scenarios increased in severity and were higher for littoral as compared to pelagic populations. Our simulations demonstrated that slower cooling in the autumn and (or) more rapid warming in spring can translate into substantial changes in the reproductive phenology of coregonines among our study groups. We expect that the changes in reproductive phenology predicted by our models, in the absence of thermal or behavioral adaptation, will have negative implications for population sustainability.

The long-term decline of the whitefish (Coregonus lavaretus) population in the boreal lake Pyhäjärvi, southwest Finland is described. Whitefish decline was associated with decreases in fecundity, winter survival of embryos, and larval density. The spawning stock was kept small by intensive fishery.

Our study introduces the first Bayesian Delay-Difference model adapted to whitefish fisheries in peri-alpine lakes. By analyzing various data, the model accurately estimates annual biomass, recruitment, stage structure of landings, and fishing mortality. These insights are invaluable for comprehending the historical trends and impacts of fishing activities on these stocks.

From the beginning of the 1980s, professional fishermen and recreational anglers, together with state services and researchers from INRA, developed an applied research program focusing on the improvement and optimisation of salmonid stocking in the Lakes Geneva and Bourget. The aim of thispaperis to retrospectively retrace the key stages of this program and its main impacts on society.

We exploredpotential drivers of larval coregoninedistributions in Lake Geneva, France and Lake Superior, USA. Depth and wind were important drivers in both lakes, date was important in Lake Geneva, and available preydensity was not important. Understanding the importance of these factors can help elucidate mechanisms regulating larval survival.

Time series of 22 vendace (Coregonus albula) populations were applied to estimate the population-specific average length-at-age and survival in early life and mature life stages. These vital rates differed widely between populations and temporally within a population. Theearly life survivalis set by the factors external to the vendace population. It is expected to decrease due to climate change, increasing the risk of local extinctions.

The Detroit River once supported a substantial lake whitefish (Coregonus clupeaformis) fishery until the early 1900s. As a result of almost 50 years of efforts to improve water and habitat quality, lake whitefish have begun to spawn in the river and viable eggs were collected. Genetic analysis of larval fish hatched from eggs collected in the field between 2005 and 2018 found thatover 80% of the hatched larvae had parents originating from Lake Erie. The estimated number of lake whitefish parents at Fighting Island decreased in the most recent collections possibly due to loss of habitat on spawning reefs due to sedimentation or a change in sample design. Our results provide additional evidence that restored spawning habitat in the Detroit River is again being used by lake whitefish and continued reproduction at these sites may improve the Great Lakes portfolio of ecological and genetic diversity.

In our study of the spawning behaviour of lake whitefish, we observed fish using a variety of habitat types during the spawning season, including a rocky spawning shoal, sandy substrates, and steeper slopes. Both sexes moved shallower at night and deeper during the day, with males moving more at night and females more during the day. This study could help inform stewardship efforts aimed at lake whitefish spawning habitat restoration and protection.

Our paper reviews the restoration and conservation strategies applied towards coregonines (e.g., whitefishes, ciscoes) across Europe, Asia, and North America. The highlighted strategies included 1) stocking of hatchery-reared fish, 2) controlling invasive species, 3) translocating fish, 4) restoring habitat, and 5) eliminating harvest or creating protected areas.

Coregonine catches declined in 67% of the 27 lakes studied across three continents in the Northern Hemisphere during the first two decades of the 21st century, with 44% showing significant trends. The analysis showed that lakes with significant catch declines were larger and nutrient-poor. The rate of change in catch appeared to be related to the trophic state of the lake, with oligotrophic and ultra-oligotrophic lakes experiencing the largest declines. While local factors such as nutrients, invasive species and fishing practices contribute to declines, the study suggests a global link between trophic state and coregonine catch trends, influenced by climate change and lake size. The results highlight a potential conflict between water quality management objectives and coregonine fisheries productivity. Efforts to achieve pristine water conditions in developed countries may reduce the productivity of coregonine fisheries. The study highlights the need for collaboration between water and fisheries managers to establish lake-specific management objectives that address the needs of all lake users, particularly in the face of increasing climate change impacts and the introduction of invasive species.