ALBERT

Description: This study examined the growth response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the proximate and mineral composition of the carcass and the apparent digestibility of the diets, in this study. The chemical analysis of the diets was conducted in duplicates and of the carcass and faeces as pooled replicates per tank (n =5 tanks per diet). The carcass samples were minced frozen using a meat grinder (MADO Primus, Germany), refrozen at−20 °C and then freeze-dried for 48 h. The samples of the experimental diets and faeces were freeze-dried for 24 h. The experimental diets and whole body samples were further homogenised in a knife grinder (5000 rpm, 30 s, Grindomix GM 200, Retsch, Germany). The moisture content, ash, crude protein, crude lipid and energy of the experimental diets, carcass and faeces was determined after AOAC (1980). Moisture content of the feeds was determined by drying the samples at 105 °C for 24 h. The moisture content of the whole body and faeces was determined by freeze-drying. Total ash content was determined by combustion of the samples in a muffle oven at 550 °C for 6 h. The total nitrogen in the feed and whole body samples was determined following the automated Kjeldahl Method. Due to small sample volume in the faeces samples, the total nitrogen was determined after the Dumas method. For all samples, the measured total nitrogen was converted to equivalent crude protein (%) by the numerical factor of 6.25. Crude lipid was determined by acid hydrolysis. Gross energy was measured in an adiabatic bomb calorimeter (Model 6100; Parr Instrument, Germany). For the analysis of the mineral content, 0.2 g of freeze-dried and homogenised samples of the experimental diets, whole body and faeces was digested in 3 mL nitric acid (HNO3) (65%, trace grade) in a microwave oven (CEM MARS5, Germany) according to DIN EN 13,805 (2014). After digestion, the samples were diluted with Milli-Q water to 50 mL. Calcium, potassium, magnesium, phosphorus, arsenic, copper, iron, manganese, yttrium and zinc concentrations were analysed in an ICP-OES (iCAP7400; Fisher Scientific, Germany). As reference fish muscle (ERM – BB422, EU) was used.

Description: This study examined the growth response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April 2019 to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the feed performance, in this study, a diet with a balanced mixture and higher level of FM replacement was included. The fish were fed twice a day (9 am and 2 pm) ad libitum. After the fish were fed in the afternoon (30 min later), the remaining pellets were netted (mesh size 1 mm) from the tanks, dried for 24 h at 50 -°C and weighed. To account for potential weight loss of the non-eaten pellets, duplicates of each experimental diet (2 g each) were incubated at 16 -°C and 100 cycles per minute in 100 mL water which was taken from the experimental recirculation system (30 °% salinity) (Obaldo et al. 2002).

Description: This study examined the growth response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April 2019 to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the growth performance, in this study, a diet with a balanced mixture and higher level of FM replacement was included. Fish were weighed to 0.2 g precision and measured in length to 0.5 cm precision every 4 weeks.

Description: This study examined the metabolic response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the metabolic response of the fish, a 1H‐nuclear magnetic resonance (NMR) spectroscopy was used to assess the metabolic profiles of muscle and liver tissue after feeding the fish the experimental diets for 16 weeks. Feed, muscle, and liver samples were ground under liquid nitrogen and approx. 200–250 mg tissue was homogenized in 5x volume of ice‐cold 0.6 M perchloric acid (PCA) (w:v). After one cycle of 20 s at 6000 rpm and 3 °C, using Precellys 24 (Bertin Technologies, Montigny‐le‐Bretonneux, France), samples were sonicated for 2 min at 0 °C and 360 W (Branson Sonifier 450, FisherScientific, Schwerte, Germany). Homogenates of the experimental diets, muscle and liver tissues were centrifuged for 2 min at 0 °C and 16,000 g, and supernatants were neutralized with ice cold potassium hydroxide (KOH) and PCA to pH 7.0–7.5. To remove precipitated potassium, perchlorate samples were centrifuged again for 2 min at 0 °C and 16,000 g. The entire supernatant was transferred, shock‐ frozen in liquid nitrogen, and stored an −80 °C for later analysis. One‐dimensional 1H‐NMR spectra for feed and tissues extracts were acquired using a vertical 9.4 T wide bore magnet with Avance III HD (Bruker‐GmbH, Ettlingen, Germany) at 400.13 MHz with a 1.7 mm diameter triple tuned (1H‐13C‐15N) probe. Each spectrum was processed and analyzed with Chenomx NMR Suite 8.4 software (Chenomx Inc., Edmonton, Canada). Before analyzing, the spectra were corrected for phase, shim and baseline and calibrated to trymethylsilyl proprionate (TSP) signal (at 0.0 ppm).

Description: This study examined the growth response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the nutritional status of the fish, glycogen, free glucose and lipid content of liver and muscle tissue were determined at the end of the experiment (t4). Following the procedure described by Keppler and Decker (1988), glycogen content was determined photometrically after enzymatic hydrolysis of glycogen to glucose. Briefly, filet and liver samples (3 individual fish per tank; 15 fish per diet in total) were grinded under liquid nitrogen, and approx. 200 mg tissue was homogenised in 5×volume of icecold 0.6 M perchloric acid (PCA) (w:v). After one cycle of 20 s at 6000 rpm and 3 °C using Precellys 24 (Bertin Technologies, France), samples were sonicated for 2 min at 0 °C and 360 W (Branson Ultrasonics Sonifier 450; Fisher Scientific, Germany), and homogenates were immediately divided for the analysis of total and free glucose concentrations.

Description: This study examined the growth response of juvenile turbot (Scophthalmus maximus) to diets with graded fishmeal (FM) replacement with plant, animal, and emerging protein sources (PLANT, PAP, and MIX) in comparison to a commercial-like diet (CTRL). The feeding experiment was carried out from April to July 2019 in the Centre for Aquaculture Research (ZAF) at the Alfred Wegener Institute for Polar and Marine research in Bremerhaven, Germany. The juvenile turbot (Scophthalmus maximus) were purchased from France Turbot (L'Épine, France) and acclimated to the recirculating aquaculture system (RAS) for 2 weeks prior to starting the 16 weeks experimental trial. To elucidate the effects of the protein sources and the level of FM replacement on the nutritional status of the fish lipid content of liver and muscle tissue were determined at the end of the experiment (t4). Muscle and liver samples (3 individual fish per tank; 15 fish per diet in total) were grinded under liquid nitrogen. Due to small volume, the individual samples of liver and muscle were pooled (n=5 tanks per diet) for the crude lipid content. Following the method of Folch et al. (1957) and Postel et al. (2000), the lipids in the muscle and liver tissue were extracted with 2:1 dichloromethanemethanol (v/v) and an aqueous solution of 0.88% potassium chloride (KCl) (w:v). Crude lipid content was determined gravimetrically to the nearest 0.001 g and calculated as the percentage of lipids of tissue wet weight.

Description: The North Sea has been and still is one of the most intensely used marine areas worldwide. Shipping (trade and private), the exploration/exploitation of energy resources (oil, gas and wind), fisheries and tourism compete for the scarce space (Holm et al. 2017). Especially, in German waters, resource-use conflicts rise between stakeholders.

Description: Coastal marine environments provide livelihoods as billions of people around the world depend greatly on sustainability efforts in the Blue Economy. In this study, we investigated how stakeholders from important Blue Economy sectors along the German North Sea coast perceive the impacts of climate change on their daily work life and the growth of the Blue Economy. In a two-stage approach we first conducted two stakeholder workshops with representatives from the regional sea food sector, science, NGOs and local authorities, in order to identify important issues linked to climate change affecting environment, society, economy and policy. In the second stage, we conducted semi-structured interviews with key knowledge holders from the Blue Economy, to evaluate and validate the most important issues identified during the first stage, and the impacts on the respective sectors. The workshop participants identified perceptible effects of climate change on their marine environment. Early career scientists showed that they possess a clear focus on measures for climate change adaptation, transdisciplinary approaches and knowledge transfer. The interviews revealed that the climate change effects could be perceived as both negative and positive, depending on the sector. Other issues, especially political decisions and developments are perceived to have a greater immediate impact on the Blue Economy than the slow progress of climate change effects. Additionally, increased human activities, in the form of new or intensified uses like marine renewable energy generation, have a greater influence and lead to conflicts between the Blue Economy sectors. Our study showed that economic and societal stakeholders in Germanys North Sea region are aware of climate change and already perceive its effects on their businesses. Synergies and conflicts between the sectors and political decisions might influence sustainable growth of the Blue Economy in highly contested regions, such as the North Sea basin, much stronger than the effects of climate change. This calls for a more flexible and adaptive approach to policymaking, taking into account the changing environmental, social and economic realities.