Flemming T. Dahlke

Thuenen-Institute of Fisheries Ecology · Aquaculture working group

Impacts of global warming and CO2‐related ocean acidification (OA) on fish reproduction may include chronic effects on gametogenesis and gamete quality, as well as acute effects on external fertilisation. Here, temperature thresholds and OA‐sensitivity of gametogenesis and fertilisation were investigated in Atlantic cod, Gadus morhua. Three broodst...

Fish embryos may be vulnerable to seawater acidification resulting from anthropogenic carbon dioxide (CO 2 ) emissions or from excessive biological CO 2 production in aquaculture systems. This study investigated CO 2 effects on embryos of the European eel ( Anguilla anguilla ), a catadromous fish that is considered at risk from climate change and t...

The identification of biological pattern is often complicated by the lack of methodologically consistent data with broad geographic coverage, especially when considering functional characteristics of organisms that differ greatly in body size and morphology. In our study (Dahlke et al. 2020), we addressed the problem of data scarcity by using diffe...

Atlantic cod (Gadus morhua) is one of the most commercially important fish species in the North Atlantic. Environmental factors, such as water temperatures, influence growth of individuals over time, thus forming population-specific growth patterns across climatic regions. Here we develop an integrative approach to investigate the role of temperatu...

Some cope better than others Increasingly, research is revealing how organisms may, or may not, adapt to a changing climate. Understanding the limitations placed by a species's physiology can help to determine whether it has an immediate potential to deal with rapid change. Many studies have looked at physiological tolerance to climate change in fi...

The vulnerability of fish embryos and larvae to environmental factors is often attributed to a lack of adult-like organ systems (gills) and thus insufficient homeostatic capacity. However, experimental data supporting this hypothesis are scarce. Here, by using Atlantic cod (Gadus morhua) as a model, the relationship between embryo vulnerability (to...

Rapid climate change in the Northeast Atlantic and Arctic poses a threat to some of the world's largest fish populations. Impacts of warming and acidification may become accessible through mechanism-based risk assessments and projections of future habitat suitability. We show that ocean acidification causes a narrowing of embryonic thermal ranges,...

Atlantic herring (Clupea harengus) is a benthic spawner, therefore its eggs are prone to encounter different water conditions during embryonic development, with bottom waters often depleted of oxygen and enriched in CO 2. Some Atlantic herring spawning grounds are predicted to be highly affected by ongoing Ocean Acidification and Warming with water...

Productivity of marine fish stocks is known to be affected by environmental and ecological drivers, and global climate change is anticipated to alter recruitment success of many stocks. While the direct effects of environmental drivers on fish early life stage survival can be quantified experimentally, indirect effects in marine ecosystems and the...

Thermal tolerance windows serve as a powerful tool for estimating the vulnerability of marine species and their life-stages to increasing temperature means and extremes. However, it remains uncertain to which extent additional drivers, such as ocean acidification, modify organismal responses to temperature. This study investigated the effects of CO...

Increasing anthropogenic activities in the Arctic represent an enhanced threat for oil pollution in a marine environment that is already at risk from climate warming. In particular, this applies to species with free-living pelagic larvae that aggregate in surface waters and under the sea ice where hydrocarbons are likely to remain for extended peri...

Abstract The project of WP 4.7 deals with the responses of the reproduction of Gadus morhua to OAW (Ocean Acidification and Warming). Our main focus is on physiological and morphological changes in reproduction, egg quality and quantity, hemoglobin phenotypes and stress responses during incubations in high CO2 concentrations. Wild-captured cod from...

Environmental drivers such as temperature and CO2 have in effect on early live stages. This overview will show different sensitivities of eggs and early larvae of crustaceans and fish. We measured mortality, developmental time, oxygen consumption and heart beat to get a comprehensive overview about the performance of these life stages and effects o...