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Citations since 2016
27 Research Items
I'm fascinated by functional responses of marine fishes to challenging environmental conditions. In particular, studying distributions and evolutionary adaptations of fishes in challenging model habitats allows me to make predictions about population dynamics in the face of global change. In this context, intrinsic factors that shape the reproductive strategies and tactics of fish are often overlooked and are therefore also of great interest to me.
June 2020 - July 2021
- Project Coordinator
- Coordinator of the DAAD funded project DatAlumni, Project manager within the Horizon 2020 project AANChOR, Organization of a conference on research data management & database development
September 2019 - February 2020
- Postdoctoral Fellow
- Lipid (fatty acid and triglyceride) quantity and composition in eggs / Analysis of continuous information from otolith micro-chemical profiles in New Zealand snapper Chrysophrys auratus
August 2017 - July 2018
Leibniz Centre for Troical Marine Research (ZMT)
- Postdoctoral Research Associate
- Assessing the ecological implications of submarine groundwater discharge on coastal coral reef ecosystems in Mauritius.
Fresh submarine groundwater discharge (fresh SGD), the efflux of terrestrial groundwater directly into the ocean, is a ubiquitous pathway for nutrient-rich freshwater to coastal ecosystems, altering their hydrography, hydrochemistry, and primary productivity. Yet only little is known about the effects of fresh SGD on the fitness of higher trophic l...
Behaviours of Clark's anemonefish Amphiprion clarkii and the dusky anemonefish Amphiprion melanopus were studied in Vanuatu. Six anemones and their resident fish were observed for typical behaviours (hiding, watching, roaming, inter‐, and intraspecific behaviour) with and without the presence of a snorkeling observer. Observer presence had signific...
The inflow of terrestrial groundwater into the ocean is increasingly recognized as an important local source of nutrients and pollutants to coastal ecosystems. Although there is evidence of a link between fresh submarine groundwater discharge (SGD)-derived nutrients and primary producer and primary consumer abundances, the effects of fresh SGD on t...
Anthropogenic factors have been identified as major stressors of nearshore environments such as estuaries, sea grass meadows and mangroves. We hypothesize that aquatic organisms functionally dependent on these habitats as nurseries respond to disturbances with subtle changes in their habitat-use patterns. We used a novel approach coupling behaviour...
As fish move between environments of different concentrations of chemical tracers at various stages during their life, their otoliths record a continuous dataset in a two-dimensional space coordinated by various trace elements. Such a continuous dataset is equivalent to a time-series and characterised by changes in the gradients of incorporated che...
Tāmure (Australasian snapper, Chrysophrys auratus) is the most commonly identified fish in pre-European Māori middens in northern New Zealand. Tāmure reproduce in open water, after which their larvae migrate to nurseries in sheltered inshore environments. The range of suitable nursery habitats in the Hauraki Gulf has declined over the last century...
The ability of different broodstock generations to provision lipids to their gametes is often overlooked in aquacultured freshwater fish. In this study we investigated the ability of two generations (F1 & F2) of Giant Kokopu (Galaxias argenteus) to provision fatty acids into their eggs. Here we show that eggs of captive-bred females (F2) displayed...
Successful recruitment in small pelagic fish populations inhabiting upwelling zones is subject to variation in fecundity and is driven by spatial and temporal fluctuations in environmental conditions, that is, mainly sea surface temperature, salinity and food availability. These fluctuations in abiotic factors have stimulated small pelagic fish pop...
Fresh submarine groundwater discharge (fresh SGD), the efflux of terrestrial groundwater directly into the ocean, is an ubiquitous pathway for nutrient-rich freshwater to coastal ecosystems, altering their hydrography, hydrochemistry, and primary productivity. Yet only little is known about the effects of fresh SGD on the fitness of higher trophic...
The gross energy content of spawning batches and the microchemistry of sagittal otoliths in individual female bonga shad Ethmalosa fimbriata were compared between contrasting sampling sites at the Senegalese southern coast and inside the hypersaline Sine Saloum Estuary. Results show that females spawning in the estuary's middle reaches invested alm...
Fecundity of marine fish species is highly variable, but trade-offs between fecundity and egg quality have rarely been observed at the individual level. We investigated spatial differences in reproductive investment of individual European sprat Sprattus sprattus (Linnaeus 1758) females by determining batch fecundity, condition indices (somatic cond...
Marine fishes employ specialized reproductive tactics in response to hydrographic fluctuations in their spawning habitats. Unprecedented environmental conditions induced by climate change will challenge these behavioral and physiological adaptations. Taking into account the key drivers of stock productivity, this work aimed at assessing the reprodu...
Converging water masses and mesoscale eddies shape habitats for larval fish assemblages in upwelling ecosystems. In the Canary Current Upwelling Ecosystem, two water masses, the North Atlantic Central Water (NACW) and South Atlantic Central Water (SACW) converge. The resulting Cape Verde Frontal Zone (CVFZ) is located off the Banc d'Arguin, Maurita...
Inversion of estuaries in the dry tropics (i.e. salinity increases upstream) against the backdrop of a globally changing climate is forcing migratory clupeid fish species to adapt quickly to modifications in their spawning habitats to ensure reproductive success. Hatching success and survival probabilities of marine fish eggs and early life stages...
The African halfbeak Hyporhamphus picarti (Hemiramphidae) is one of the most abundant species within the ichthyoplankton community of the Sine Saloum estuary (Senegal). A year-round occurrence of larvae suggests that the Sine Saloum is an important spawning habitat for this species. Annual fluctuations in water temperature, however, can have severe...
Little is known about the concerted influence of temperature and salinity on the fecundity of clupeid fishes. Due to a globally changing climate, both physical parameters might act as stressors, severely affecting the reproductive potential of clupeid fish populations inhabiting tropical estuaries. Differences in relative batch fecundities, the gon...
Mangrove ecosystems have long been considered essential habitats and are commonly viewed and referred to as “nursery areas”. They are highly sensitive to climate change, and environmental transformations in these ecosystems are expected. The Sine Saloum estuary is a case of a system affected by global climate change where reduced precipitation and...
European sardine (Sardina pilchardus) and round sardinella (Sardinella aurita) comprise two-thirds of total landings of small pelagic fishes in the Canary Current Eastern Boundary Ecosystem (CCEBE). Their spawning habitat is the continental shelf where upwelling is responsible for high productivity. While upwelling intensity is predicted to change...
Senegal is the southern tip of the Canary upwelling system. Its coastal ocean hosts an upwelling center which shapes sea surface temperatures between latitudes 12o and 15o N. Near this latter latitude, the Cape Verde headland and a sudden change in shelf cross-shore profile are major sources of heterogeneity in the southern Senegal upwelling sector...
Hyporhamphus picarti (Hemiramphidae) is one of the dominant species of the ichthyoplankton community in the Sine Saloum estuary (Senegal) and is abundant year-round. This suggests that the Sine Saloum is an important nursery ground for the species. Throughout the year, H. picarti larvae show higher abundance in February (cool and dry season) and Ju...
As a consequence of the Sahelian drought, the Sine Saloum (Senegal) has become an “inverse estuary”, i.e. salinity increases upstream. The rather extreme environmental conditions inside the estuary were used to investigate the reproductive response of Ethmalosa fimbriata (Clupeidae) at the outer range of its physiological performance curve. Females...
The global change disrupts the ecosystem and thus the dynamic of renewable marine resources exploited. In West African countries among all impacts of the global change the overexploitation have been well studied but lesser the impact of climate change particularly on small scale fisheries, despite that in these countries the management of fisheries...
The circulation associated with coastal upwelling is well understood in simple 2D alongshore invariant situations. Southern Senegal is the southern tip of the Canary upwelling system. Its coastal ocean hosts an upwelling center which shapes sea surface temperatures over several degrees in latitudes, ~ between 12 and 15N. Near this latter latitude,...
Fishes generally cope with extreme ambient conditions by varying their life history traits due to either genetic changes or phenotypic plasticity. Salinity variations inside the hyperhaline Saloum estuary (Senegal) were used to investigate the reproductive response of male clupeids to extreme environmental fluctuations. Male Ethmalosa fimbriata (Bo...
The upwelling ecosystem off the coast of Senegal is highly productive and usually dominated in biomass by Sardinella aurita. During the AWA cruise in March of 2014 (F/RV Thalassa off Mauritania, Senegal, and the Gambia) continuous egg samples were collected onboard with a CUFES (Continuous Underwater Fish Eggs Sampler). Laboratory analysis of these...
I am looking for an easy to establish methodology to measure lipid classes (FFA, TAG, SE, WE, ST, PL) from lipid extracted samples on our HPLC with a binary pump (2 eluents) and equipped with a diode array detector (DAD) or a fluorescence detector (FLD).
Maybe someone is running the same setup in their laboratory or can point me to a published methodology section. Any help is very much appreciated!
Dear all, I am looking for precipitation data for Mauritius for the years 2017 and 2018. Unfortunately, the Mauritius Meteorological Services do not appear to have an archive of their monthly bulletins on rainfall: https://web.archive.org/web/20190123113053/http://metservice.intnet.mu/publication.php Thanks for the help!
I am looking for precipitation data for Mauritius for the years 2017 and 2018. Unfortunately, the Mauritius Meteorological Services do not appear to have an archive of their monthly bulletins:
Thanks for the help!
currently we are trying to read daily growth increments of damselfish (Chrysiptera glauca) from Mauritius. However, we have yet to find a perfect methodology to make the increments more readable/visible.
For small otoliths the most promising method so far was to
1. Burn otolith (10-20 sec over bunsen burner)
2. store otolith in immersion oil
(Picture 1 and 2)
Other methods used include
1. glue otolith on a glass slide
2. grind otolith down (using 4000 sand paper)
3. polish otolith (using colloidal silica suspension)
4. burn otolith (over bunsen burner for 10-20 sec)
4. stain otolith with 0.1% toluidin blue
(Picture 3, rings seem too big)
I would be extremely happy about any suggestions regarding otolith processing to enhance readability.
We started a new project which involves the identification of coral reef and coastal fish species in Mauritius. I would be very glad about any literature suggestions, especially identification keys.
During our last field work we encountered this fish species in the intertidal zone in Mauritius (Indian Ocean). It has a striking fluorescent V on its head, clearly visible when viewed from above. The fish is ca. 3 cm in total length. I would very much appreciate a little help in identifying the species! Thanks a lot upfront.
This is a multidisciplinary collaborative research programme with archaeologists and marine scientists. We are conducting a set of individual projects that draw on archaeological data and contemporary fisheries and marine science in order to address a range of issues around the exploitation of marine resources in New Zealand.
Knowledge on the role of intrinsic reproductive strategies on gamete quality in wild and aquacultured fishes remain sparse. We set out to challenge what is known about these pre-programmed reproductive strategies through the study of maternal resource provisioning. Fatty acids, triglycerides, and amino acid are particularly valuable biomarkers that are transferred from mothers to gametes, thus determining the cytoplasmic quality of eggs. Equally, transgenerational plasticity can also be studied through provisioning of said molecules, and nucleic acids. Tracing the flux of bio markers from mothers to gametes will lead to novel insights concerning the mechanisms determining reproductive strategies and success - information which is highly relevant for stock and aquaculture management. Enquiries we are interested in pursuing 1. Maternal energetics and resource provisioning 2. Gamete quality ascertained through cytoplasmic parameters 3. Hatching rates and larval survival 4. Adaptive/non-adaptive transgenerational plasticity 5. Income vs capital breeding strategy
‘AWA’ PROJECT • Build the foundation of a West African observatory • Create a subregional task force on the ecosystem approach to the management of fisheries and the marine environment in West African waters under the effect of climate change Climate variability influences the state and functioning of marine ecosystems (Planque et al., 2010), and the interactions between fishing and climate are the main drivers of change in marine systems. This interaction impacts on ecosystems, and thus on those who rely on the services they provide (Perry et al., 2010). The pelagic productivity in the West-African marine upwelling ecosystems sustains one of the world’s largest small pelagic fisheries. Tropical fisheries are particularly influenced by environmental variability and instability, raising the problem of the interactions between the various components of the ecosystem, and the dynamics of the environment, of fish stocks and of fishing communities. The present integrated large cooperative project proposes a strategic partnership that will be capable of developing a vision and the scientific basis for an ecosystem approach to the management of fisheries and the marine environment (‘EAMME’) in West African waters to be implemented within national and international organisation e.g. CECAF assessments as a long-term endeavour focusing on small pelagic. This sector is of vital importance for the economies of West African littoral countries in terms of both artisanal fisheries that generate significant national food supplies and of licensed foreign fisheries, including foreign recreational fisheries. It has been suggested that the fisheries sector has further potential for growth (Fonseca, 2000), which highlights the need for scientific advice to underpin management decisions. In turn, improved resource management will be a key element in managing the ecosystem in West African waters in order to safeguard sustainable fishery production in the area. EAMME calls for a multidisciplinary approach comprising marine and fisheries ecology, biogeochemistry, physical oceanography, climate research, economy and earth observation data from space. Combining process studies of ecosystem functioning, long-term biological and physical monitoring and modelling, the final goal is to develop indicator-based management and adaptive decision support tools for EAMME in the context of global change and regional cooperation, since the same stocks are shared by several West African countries (see CCLME). To achieve this goal, the laboratories involved will work in two main areas of research: the monitoring of oceanic biological resources (assessment) and their functioning and modelling (ecological processes). These are both research areas of outstanding importance in the broader scientific context of the analysis of global change, and of paramount relevance for West Africa. Both research activities will be done with a particular interest in capacity building of West African partners’ i.e. approach to development that focuses on understanding the obstacles that inhibit West African research infrastructure from realizing their developmental goals while enhancing the abilities that will allow them to achieve measurable and sustainable results for EAMME. The first line of research will focus on improving the description of physical, biogeochemical and ecological processes and the development of monitoring techniques and methodologies. The second line of research will assess the usefulness of such data (and results) for parameterizing, calibrating and validating models for the management, process description and forecasting of the global change scenario. The overall vision of the project is to establish a synergistic network of West African researchers working on their local marine resources in their associated habitats, benefitting from and building upon past and ongoing cooperation projects involving working groups in West Africa and in Germany and France and making use of existing structures. Some of the partnerships and framework required have already been established with various institutions in West African countries that are already committed to this crucial goal, and new university laboratories are springing up. However, capacities are still small, and developing countries need significant support to develop their national and regional networks (e.g. RFMOs) to international standards of governance, and to develop their scientific infrastructure in the context of global change.