Ecomorphology of largemouth bass relative to a native trophic analogue explains its high invasive impact
Luger, A.M. ; South, J. ; Alexander, M.E. ; Ellender, B.R. ; Weyl, O.L.F. ; Nagelkerke, L.A.J. - \ 2020
Biological Invasions 22 (2020). - ISSN 1387-3547 - p. 2223 - 2233.
Competition - Conservation - Freshwater - Functional traits - Handling time
Predicting and understanding the impact of biological invaders is a global ecological imperative. Progress has been made through the application of phenomenological analysis via comparative functional response analysis. However, little is known about the mechanisms which drive high-magnitude functional responses of invasive species, especially when compared to trophically analogous natives. Largemouth bass Micropterus salmoides is a freshwater invasive species evaluated as a more efficient predator, with a higher-magnitude functional response, compared to a native analogue, the Cape kurper Sandelia capensis. In order to determine what traits drive this difference we quantified handling time behaviours (detection time, catch time, processing time) of both predator species and prey/predator size ratio, and employ an ecomorphological approach to determine whether largemouth bass is a more specialised predator than Cape kurper. There was no difference in detection time between the species, but largemouth bass were significantly and on average five times faster at catching prey than Cape kurper. Both species’ processing time was positively related to prey size, but Cape kurper was on average 4.5 times faster than largemouth bass. Ecomorphological data indicate that largemouth bass was the more specialised pursuit hunter for fish, whereas Cape kurper was better at ambush hunting. This suggests that the ecological impact of largemouth bass may be exacerbated in areas where there is habitat simplification which can lead to the extirpation of local small-bodied fish. In addition, there may be non-consumptive detrimental effects on trophically analogous natives through competitive exclusion.
The genetic correlation between feed conversion ratio and growth rate affects the design of a breeding program for more sustainable fish production
Besson, Mathieu ; Komen, Hans ; Rose, Gus ; Vandeputte, Marc - \ 2020
Genetics, Selection, Evolution 52 (2020)1. - ISSN 0999-193X
Background: Most fish breeding programs aim at improving growth rate and include feed conversion ratio (FCR) neither in the breeding goal nor in the selection index, although decreasing FCR is known to increase farm profit and decrease environmental impacts. This is because FCR is difficult to measure in fish that live in groups and FCR is assumed to have a favourable (negative) genetic correlation with growth, although the magnitude of this correlation is unknown. We investigated the effect of the genetic correlation between growth and FCR on the economic and environmental responses of a two-trait breeding goal (growth and FCR), compared to a single-trait breeding goal (growth only). Next, we evaluated the weights to assign to growth and FCR in a two-trait breeding goal to maximize sustainability of fish production. Methods: We used pseudo-best linear unbiased prediction (BLUP) index calculations to simulate a breeding program for sea bass. For the single-trait breeding goal, the trait in the breeding goal and in the index was thermal growth coefficient (TGC) and for the two-trait breeding goal, the traits in the breeding goal were TGC and FCR and the traits in the index were TGC and percentage of fat in the dorsal muscle (an indirect measure of FCR). We simulated responses to selection for genetic and phenotypic correlations between TGC and FCR ranging from 0 to - 0.8. Then, in the two-trait breeding goal, we calculated the economic return and the change in eutrophication when using economic values (EV) or environmental values (ENV). Results: When the genetic correlation between TGC and FCR was lower than - 0.45, we found major differences in economic returns and in eutrophication between single and two-trait breeding programs. At a correlation of - 0.25, the two-trait breeding goal based on EV increased economic return by 25% compared to the single-trait breeding goal, while using ENV decreased eutrophication by 1.34% per ton of fish produced after one generation of selection. Conclusions: The genetic correlation between TGC and FCR affects the magnitude of economic losses due to omitting FCR in the breeding program. In addition, the genetic correlation affects the importance of choosing EV or ENV to reduce eutrophication and increase profit.
Future directions for the concept of salutogenesis: a position article
Bauer, G.F. ; Roy, M. ; Bakibinga, P. ; Contu, P. ; Downe, S. ; Eriksson, M. ; Espnes, G.A. ; Jensen, B.B. ; Juvinya Canal, D. ; Lindström, B. ; Mana, A. ; Mittelmark, M.B. ; Morgan, A.R. ; Pelikan, J.M. ; Saboga-Nunes, L. ; Sagy, S. ; Shorey, S. ; Vaandrager, L. ; Vinje, H.F. - \ 2020
Health Promotion International 35 (2020)2. - ISSN 0957-4824 - p. 187 - 195.
Aaron Antonovsky advanced the concept of salutogenesis almost four decades ago (Antonovsky, Health, Stress and Coping. Jossey-Bass, San Francisco, CA, 1979; Unravelling the Mystery of Health. Jossey-Bass, San Francisco, CA, 1987). Salutogenesis posits that life experiences shape the sense of coherence (SOC) that helps to mobilize resources to cope with stressors and manage tension successfully (determining one’s movement on the health Ease/Dis-ease continuum). Antonovsky considered the three-dimensional SOC (i.e. comprehensibility, manageability, meaningfulness) as the key answer to his question about the origin of health. The field of health promotion has adopted the concept of salutogenesis as reflected in the international Handbook of Salutogenesis (Mittelmark et al., The Handbook of Salutogenesis. Springer, New York, 2016). However, health promotion mostly builds on the more vague, general salutogenic orientation that implies the need to foster resources and capacities to promote health and wellbeing. To strengthen the knowledge base of salutogenesis, the Global Working Group on Salutogenesis (GWG-Sal) of the International Union of Health Promotion and Education produced the Handbook of Salutogenesis. During the creation of the handbook and the regular meetings of the GWG-Sal, the working group identified four key conceptual issues to be advanced: (i) the overall salutogenic model of health; (ii) the SOC concept; (iii) the design of salutogenic interventions and change processes in complex systems; (iv) the application of salutogenesis beyond health sector. For each of these areas, we first highlight Antonovsky’s original contribution and then present suggestions for future development. These ideas will help guide GWG-Sal’s work to strengthen salutogenesis as a theory base for health promotion.
A user guide to environmental protistology: primers, metabarcoding, sequencing, and analyses
Geisen, Stefan ; Vaulot, Daniel ; Mahe, Frederic ; Lara, Enrique ; Vargas, Colomban de; Bass, David - \ 2019
BioRxiv - 34 p.
Protists – all eukaryotes besides fungi, animals, and plants - represent a major part of the taxonomic and functional diversity of eukaryotic life on the planet and drive many ecosystem processes. However, knowledge of protist communities and their diversity lags behind that of most other groups of organisms, largely due to methodological constraints. While protist communities differ markedly between habitats and biomes, they can be studied in very similar ways. Here we provide a guide to current molecular approaches used for studying protist diversity, with a particular focus on amplicon-based high-throughput sequencing (metabarcoding). We highlight that the choice of suitable primers artificially alters community profiles observed in metabarcoding studies. While there are no true ‘universal’ primers to target all protist taxa as a whole, we identify some primer combinations with a wide taxonomic coverage and provide detailed information on their properties. Although environmental protistan ecological research will probably shift towards PCR-free metagenomics or/and transcriptomic approaches in a near future, metabarcoding will remain the method of choice for in-depth community analyses and taxon inventories in biodiversity surveys and ecological studies, due its great cost-efficiency, sensitivity, and throughput. In this paper we provide a guide for scientists from a broad range of disciplines to implement protists in their ecological analyses
Brominated flame retardants in animal derived foods in the Netherlands between 2009 and 2014
Gebbink, Wouter A. ; Lee, Martijn K. van der; Peters, Ruud J.B. ; Traag, Wim A. ; Dam, Guillaume ten; Hoogenboom, Ron L.A.P. ; Leeuwen, Stefan P.J. van - \ 2019
Chemosphere 234 (2019). - ISSN 0045-6535 - p. 171 - 178.
Eggs - Fish - HBCDD - Meat - Milk - PBDE
Polybrominated diphenylethers (PBDEs), hexabromocyclododecanes (HBCDDs) and tetrabromobisphenol A (TBBPA) were monitored in various foods from terrestrial and aquatic animal origin (>850 samples), collected in the Netherlands between 2009 and 2014. The terrestrial samples included meat/fat from 7 animal species (including bovines, pigs, broilers and sheep), bovine milk and hen eggs. Dominant PBDE congeners in these samples were BDE-47, -99, -100, -153 and -183. The meat/fat generally contained the highest ∑PBDE concentrations compared to eggs and milk, with meat from deer, horse and sheep containing the highest concentrations. Generally declining ∑PBDE concentrations were observed between 2009 and 2014, however, this was only significant in pig meat and hen's eggs. The aquatic samples included fillets from 18 species (including herring, haddock and salmon), brown crab parts, shrimp and mussels, and the highest ∑PBDE concentrations were seen in body parts of brown crab, herring, mackerel, salmon and sea bass (on wet weight basis). Patterns generally contained more congeners (i.e., BDE-28, -49 and -66) additional to the aforementioned congeners found in terrestrial samples. Herring, sea bass and brown crab (body parts) contained among the highest PBDE concentrations. TBBPA was only detected in 3 individual samples (bovine and broiler meat and haddock), while α-HBCDD was the dominant diastereomer detected in several terrestrial and aquatic samples. When detected, TBBPA and HBCDD concentrations were generally in the same order as ∑PBDE concentrations in the same sample types.
Forecasting product sales with a stochastic Bass model
Grasman, Johan ; Kornelis, Marcel - \ 2019
Journal of Mathematics in Industry 9 (2019). - ISSN 2190-5983 - 10 p.
Bass model - Confidence domain - Ornstein–Uhlenbeck process - Sensitivity of parameter to data
With the Bass model and data of previous sales a point estimate of future sales can be made for the purpose of stock management. In order to obtain information about the accuracy of that estimate a confidence interval can be of use. In this study such an interval is constructed from a Bass model extended with a noise term. The size of the noise is assumed to be proportional with the yearly sales. It is also assumed that the deviation from the deterministic solution is sufficiently small to make a small noise approximation. This perturbation takes the form of a time dependent Ornstein–Uhlenbeck process. For the variance of the perturbation an exact expression can be given which is needed in order to obtain confidence intervals.
|Targeting fish vaccination
Wiegertjes, G.F. - \ 2018
Bulletin of the European Association of Fish Pathologists 38 (2018)3. - ISSN 0108-0288 - p. 98 - 103.
Some 5 years ago the TargetFish project kicked off with 30 partners from 10 EU member states, 3 associated countries (Norway, Israel) and one International Cooperation Partner Country (Chile), to 'improve fish vaccination strategies to help prevent important diseases in the European aquaculture industry'. The characteristic of TargetFish has been the close cooperation between academic research groups and enterprises, both more or less equally represented in the consortium. The project brought together researchers on fish pathology and immunology who all shared one main interest: fish vaccination. The ambitious consortium chose to target vaccination against more than 10 important viral or bacterial pathogens of Atlantic salmon, rainbow trout, common carp, sea bass, seabream and turbot with the overall aim of 'advancing the development of existing (but sometimes insufficient or suboptimal) and new prototype vaccines'. Please find below, not a summary of progress for all pathogens and vaccines addressed in the context of the TargetFish project, but a number of highlights of this large collaborative project funded by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993). The 5 year project finished on lst October 2017.
Out of the pot and into the fire : Explaining the vulnerability of an endangered small headwater stream fish to black-bass Micropterus spp. invasion
Ellender, B.R. ; Weyl, O.L.F. ; Alexander, M.E. ; Luger, A.M. ; Nagelkerke, L.A.J. ; Woodford, D.J. - \ 2018
Journal of Fish Biology 92 (2018)4. - ISSN 0022-1112 - p. 1035 - 1050.
Behaviour - Endangered fish - Evolutionary response - Micropterus - Naïveté - Pseudobarbus afer
Introduced predatory fishes have had consistently severe consequences for native fishes in stream environments around the world, although the drivers of these effects are often unclear. In the Swartkops River headwaters in South Africa, native Eastern Cape redfin Pseudobarbus afer were always absent from sites occupied by non-native black basses Micropterus salmoides and Micropterus dolomieu, but generally co-occurred with the native predators Anguilla marmorata and Anguilla mossambica. A natural experiment provided by flood-mediated recolonization of black-bass occupied sites by P. afer demonstrated depletion in black-bass invaded sites. Field behavioural observations of P. afer indicated that they foraged among benthic cover during the day, but suspended in open water at night. As the nocturnal A. marmorata and A. mossambica foraged actively within structural cover at night and M. dolomieu and M. salmoides are diurnal or crepuscular predators, P .afer is thus optimized to avoid predation by native anguillid predators and not the functionally unique predatory black basses. The integration of distributional, temporal population dynamics and behavioural data suggests that the severe effects of Micropterus spp. are probably a consequence of prey naïveté and behaviour evolved to evade native predators.
Recreational sea fishing in Europe in a global context-Participation rates, fishing effort, expenditure, and implications for monitoring and assessment
Hyder, Kieran ; Weltersbach, Marc Simon ; Armstrong, Mike ; Ferter, Keno ; Townhill, Bryony ; Ahvonen, Anssi ; Arlinghaus, Robert ; Baikov, Andrei ; Bellanger, Manuel ; Birzaks, Janis ; Borch, Trude ; Cambie, Giulia ; Graaf, Martin De; Diogo, Hugo M.C. ; Dziemian, Łukasz ; Gordoa, Ana ; Grzebielec, Ryszard ; Hartill, Bruce ; Kagervall, Anders ; Kapiris, Kostas ; Karlsson, Martin ; Kleiven, Alf Ring ; Lejk, Adam M. ; Levrel, Harold ; Lovell, Sabrina ; Lyle, Jeremy ; Moilanen, Pentti ; Monkman, Graham ; Morales-Nin, Beatriz ; Mugerza, Estanis ; Martinez, Roi ; O'Reilly, Paul ; Olesen, Hans Jakob ; Papadopoulos, Anastasios ; Pita, Pablo ; Radford, Zachary ; Radtke, Krzysztof ; Roche, William ; Rocklin, Delphine ; Ruiz, Jon ; Scougal, Callum ; Silvestri, Roberto ; Skov, Christian ; Steinback, Scott ; Sundelöf, Andreas ; Svagzdys, Arvydas ; Turnbull, David ; Hammen, Tessa van der; Voorhees, David Van; Winsen, Frankwin Van; Verleye, Thomas ; Veiga, Pedro ; Vølstad, Jon-Helge ; Zarauz, Lucia ; Zolubas, Tomas ; Strehlow, Harry V. - \ 2018
Fish and Fisheries 19 (2018)2. - ISSN 1467-2960 - p. 225 - 243.
European marine recreational fisheries - fisheries assessment and management - fishing effort and expenditure - participation - surveys and monitoring of marine recreational fisheries
Marine recreational fishing (MRF) is a high-participation activity with large economic value and social benefits globally, and it impacts on some fish stocks. Although reporting MRF catches is a European Union legislative requirement, estimates are only available for some countries. Here, data on numbers of fishers, participation rates, days fished, expenditures, and catches of two widely targeted species were synthesized to provide European estimates of MRF and placed in the global context. Uncertainty assessment was not possible due to incomplete knowledge of error distributions; instead, a semi-quantitative bias assessment was made. There were an estimated 8.7 million European recreational sea fishers corresponding to a participation rate of 1.6%. An estimated 77.6 million days were fished, and expenditure was €5.9 billion annually. There were higher participation, numbers of fishers, days fished and expenditure in the Atlantic than the Mediterranean, but the Mediterranean estimates were generally less robust. Comparisons with other regions showed that European MRF participation rates and expenditure were in the mid-range, with higher participation in Oceania and the United States, higher expenditure in the United States, and lower participation and expenditure in South America and Africa. For both northern European sea bass (Dicentrarchus labrax, Moronidae) and western Baltic cod (Gadus morhua, Gadidae) stocks, MRF represented 27% of the total removals. This study highlights the importance of MRF and the need for bespoke, regular and statistically sound data collection to underpin European fisheries management. Solutions are proposed for future MRF data collection in Europe and other regions to support sustainable fisheries management.
Acoustic dose-behavioral response relationship in sea bass (Dicentrarchus labrax) exposed to playbacks of pile driving sounds
Kastelein, Ronald A. ; Jennings, Nancy ; Kommeren, Aimée ; Helder-Hoek, Lean ; Schop, Jessica - \ 2017
Marine Environmental Research 130 (2017). - ISSN 0141-1136 - p. 315 - 324.
Acoustics - Behavior - Marine fish - Offshore industry - Pile driving - Sea bass - Startle response - Wind park
The foundations of offshore wind turbines are attached to the sea bed by percussion pile driving. Pile driving sounds may affect the behavior of fish. Acoustic dose-behavioral response relationships were determined for sea bass in a pool exposed for 20 min to pile driving sounds at seven mean received root-mean-square sound pressure levels [SPLrms; range: 130-166 dB re 1 μPa; single strike sound exposure level (SELss) range: 122-158; 6 dB steps]. Initial responses (sudden, short-lived changes in swimming speed and direction) and sustained responses (changes in school cohesion, swimming depth, and speed) were quantified. The 50% initial response threshold occurred at an SELss of 131 dB re 1 μPa2 s for 31 cm fish and 141 dB re 1 μPa2 s for 44 cm fish; the small fish thus reacted to lower SELss than the large fish. Analysis showed that there is no evidence, even at the highest sound level, for any consistent sustained response to sound exposure by the study animals. If wild sea bass are exposed to pile driving sounds at the levels used in the present study, there are unlikely to be any adverse effects on their ecology, because the initial responses after the onset of the piling sound observed in this study were short-lived.
UniEuk: Time to Speak a Common Language in Protistology!
Berney, Cédric ; Ciuprina, Andreea ; Bender, Sara ; Brodie, Juliet ; Edgcomb, Virginia ; Kim, Eunsoo ; Rajan, Jeena ; Wegener Parfrey, Laura ; Adl, Sina ; Audic, Stéphane ; Bass, David ; Caron, David A. ; Cochrane, Guy ; Czech, Lucas ; Dunthorn, Micah ; Geisen, Stefan - \ 2017
Journal of Eukaryotic Microbiology 64 (2017)3. - ISSN 1066-5234 - p. 407 - 411.
Community expertise - Diversity - Eukaryotes - EukBank - EukMap - EukRef - Taxonomy
Universal taxonomic frameworks have been critical tools to structure the fields of botany, zoology, mycology, and bacteriology as well as their large research communities. Animals, plants, and fungi have relatively solid, stable morpho-taxonomies built over the last three centuries, while bacteria have been classified for the last three decades under a coherent molecular taxonomic framework. By contrast, no such common language exists for microbial eukaryotes, even though environmental '-omics' surveys suggest that protists make up most of the organismal and genetic complexity of our planet's ecosystems! With the current deluge of eukaryotic meta-omics data, we urgently need to build up a universal eukaryotic taxonomy bridging the protist -omics age to the fragile, centuries-old body of classical knowledge that has effectively linked protist taxa to morphological, physiological, and ecological information. UniEuk is an open, inclusive, community-based and expert-driven international initiative to build a flexible, adaptive universal taxonomic framework for eukaryotes. It unites three complementary modules, EukRef, EukBank, and EukMap, which use phylogenetic markers, environmental metabarcoding surveys, and expert knowledge to inform the taxonomic framework. The UniEuk taxonomy is directly implemented in the European Nucleotide Archive at EMBL-EBI, ensuring its broad use and long-term preservation as a reference taxonomy for eukaryotes.
Soil protistology rebooted: 30 fundamental questions to start with
Geisen, Stefan ; Mitchell, Edward A.D. ; Wilkinson, David M. ; Adl, Sina ; Bonkowski, Michael ; Brown, Matthew W. ; Fiore-Donno, Anna Maria ; Heger, Thierry J. ; Jassey, Vincent E.J. ; Krashevska, Valentyna ; Lahr, Daniel J.G. ; Marcisz, Katarzyna ; Mulot, Matthieu ; Payne, Richard ; Singer, David ; Anderson, O.R. ; Charman, Dan J. ; Ekelund, Flemming ; Griffiths, Bryan S. ; Rønn, Regin ; Smirnov, Alexey ; Bass, David ; Belbahri, Lassaâd ; Berney, Cédric ; Blandenier, Quentin ; Chatzinotas, Antonis ; Clarholm, Marianne ; Dunthorn, Micah ; Feest, Alan ; Fernández, Leonardo D. ; Foissner, Wilhelm ; Fournier, Bertrand ; Gentekaki, Eleni ; Hájek, Michal ; Helder, Hans ; Jousset, Alexandre ; Koller, Robert ; Kumar, Santosh ; Terza, Antonietta La; Lamentowicz, Mariusz ; Mazei, Yuri ; Santos, Susana S. ; Seppey, Christophe V.W. ; Spiegel, Frederick W. ; Walochnik, Julia ; Winding, Anne ; Lara, Enrique - \ 2017
Soil Biology and Biochemistry 111 (2017). - ISSN 0038-0717 - p. 94 - 103.
Protists are the most diverse eukaryotes. These microbes are keystone organisms of soil ecosystems and
regulate essential processes of soil fertility such as nutrient cycling and plant growth. Despite this,
protists have received little scientific attention, especially compared to bacteria, fungi and nematodes in
soil studies. Recent methodological advances, particularly in molecular biology techniques, have made
the study of soil protists more accessible, and have created a resurgence of interest in soil protistology.
This ongoing revolution now enables comprehensive investigations of the structure and functioning of
soil protist communities, paving the way to a new era in soil biology. Instead of providing an exhaustive
review, we provide a synthesis of research gaps that should be prioritized in future studies of soil
protistology to guide this rapidly developing research area. Based on a synthesis of expert opinion we
propose 30 key questions covering a broad range of topics including evolution, phylogenetics, functional
ecology, macroecology, paleoecology, and methodologies. These questions highlight a diversity of topics
that will establish soil protistology as a hub discipline connecting different fundamental and applied
fields such as ecology, biogeography, evolution, plant-microbe interactions, agronomy, and conservation
biology. We are convinced that soil protistology has the potential to be one of the most exciting frontiers
Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming
Besson, M. ; Boer, I.J.M. de; Vandeputte, M. ; Arendonk, J.A.M. van; Quillet, E. ; Komen, H. ; Aubin, J. - \ 2017
PLoS ONE 12 (2017)3. - ISSN 1932-6203
In sea cage fish farming, production quotas aim to constrain the impact of fish farming on the surrounding ecosystem. It is unknown how these quotas affect economic profitability and environmental impact of genetic improvement. We combined bioeconomic modelling with life cycle assessment (LCA) to calculate the economic (EV) and environmental (ENV) values of thermal growth coefficient (TGC) and feed conversion ratio (FCR) of sea bass reared in sea cages, given four types of quota commonly used in Europe: annual production (Qprod), annual feed distributed (Qannual-feed), standing stock (Qstock), and daily feed distributed (Qdaily-feed). ENV were calculated for LCA impact categories climate change, eutrophication and acidification. ENV were expressed per ton of fish produced per year (ENV(fish)) and per farm per year (ENV(farm)). Results show that irrespective of quota used, EV of FCR as well as ENV(fish) and ENV(farm) were always positive, meaning that improving FCR increased profit and decreased environmental impacts. However, the EV and the ENV(fish) of TGC were positive only when quota was Qstock or Qdaily-feed. Moreover, the ENV(farm) of TGC was negative in Qstock and Qdaily-feed quotas, meaning that improving TGC increased the environmental impact of the farm. We conclude that Qstock quota and Qdaily-feed quota are economically favorable to a genetic improvement of TGC, a major trait for farmers. However, improving TGC increases the environmental impact of the farm. Improving FCR represents a good opportunity to balance out this increase but more information on its genetic background is needed to develop breeding programs improving FCR.
Inspanningsadviezen voor snoekbaars, baars, blankvoorn en brasem in het IJssel-/Markermeer : visseizoen 2017/2018
Tiën, Nicola ; Hammen, Tessa van der; Vries, Pepijn de; Schram, Edward ; Steenbergen, Josien - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C018/17) - 79
snoekbaars - baars - rutilus rutilus - abramis brama - vissen - visserij - visstand - ijsselmeer - pike perch - bass - rutilus rutilus - abramis brama - fishes - fisheries - fish stocks - lake ijssel
Het Ministerie van Economische Zaken wil komen tot wetenschappelijk onderbouwd duurzaam beheer van snoekbaars, baars, blankvoorn en brasem in het IJsselmeer en Markermeer. Voor alle vier bestanden is de beleidsdoelstelling voor visseizoen 2017/2018 geformuleerd in het document “Toekomstbeeld visstand IJsselmeer/Markermeer – synthesedocument’. Hierin wordt in ieder geval gestreefd naar ‘een evenwichtiger lengte-opbouw van de bestanden met meer grotere exemplaren en een groter aantal jaarklassen’, als ook ‘een toename van de (paai)bestanden’. Voor het behalen van deze beleidsdoelstellingen zijn inspanningsadviezen gevraagd over de staandwantvisserij en de zegenvisserij, gecombineerd voor het IJsselmeer en Markermeer.
Alien Pathogens on the Horizon : Opportunities for Predicting their Threat to Wildlife
Roy, Helen E. ; Hesketh, Helen ; Purse, Bethan V. ; Eilenberg, Jørgen ; Santini, Alberto ; Scalera, Riccardo ; Stentiford, Grant D. ; Adriaens, Tim ; Bacela-Spychalska, Karolina ; Bass, David ; Beckmann, Katie M. ; Bessell, Paul ; Bojko, Jamie ; Booy, Olaf ; Cardoso, Ana Cristina ; Essl, Franz ; Groom, Quentin ; Harrower, Colin ; Kleespies, Regina ; Martinou, Angeliki F. ; Oers, Monique M. van; Peeler, Edmund J. ; Pergl, Jan ; Rabitsch, Wolfgang ; Roques, Alain ; Schaffner, Francis ; Schindler, Stefan ; Schmidt, Benedikt R. ; Schönrogge, Karsten ; Smith, Jonathan ; Solarz, Wojciech ; Stewart, Alan ; Stroo, Arjan ; Tricarico, Elena ; Turvey, Katharine M.A. ; Vannini, Andrea ; Vilà, Montserrat ; Woodward, Stephen ; Wynns, Anja Amtoft ; Dunn, Alison M. - \ 2017
Conservation Letters 10 (2017)4. - ISSN 1755-263X - p. 477 - 484.
Environmental hazard - Horizon scanning - Invasive alien species - Legislation - Wildlife diseases
According to the Convention on Biological Diversity, by 2020 invasive alien species (IAS) should be identified and their impacts assessed, so that species can be prioritized for implementation of appropriate control strategies and measures put in place to manage invasion pathways. For one quarter of the IAS listed as the "100 of the world's worst" environmental impacts are linked to diseases of wildlife (undomesticated plants and animals). Moreover, IAS are a significant source of "pathogen pollution" defined as the human-mediated introduction of a pathogen to a new host or region. Despite this, little is known about the biology of alien pathogens and their biodiversity impacts after introduction into new regions. We argue that the threats posed by alien pathogens to endangered species, ecosystems, and ecosystem services should receive greater attention through legislation, policy, and management. We identify 10 key areas for research and action, including those relevant to the processes of introduction and establishment of an alien pathogen and to prediction of the spread and associated impact of an alien pathogen on native biota and ecosystems. The development of interdisciplinary capacity, expertise, and coordination to identify and manage threats was seen as critical to address knowledge gaps.
WET-tests with sea bass (Dicentrarchus labrax) eggs with discharge water of the MICROFADE II system : addendum to IMARES report C079/16
Kaag, N.H.B.G. - \ 2016
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C088/16) - 14
dicentrarchus - fish eggs - saline water - fresh water - embryonic development - dicentrarchus - visseneieren - zout water - zoet water - embryonale ontwikkeling
Coprophilic amoebae and flagellates, including Guttulinopsis, Rosculus and Helkesimastix, characterise a divergent and diverse rhizarian radiation and contribute to a large diversity of faecal-associated protists
Bass, David ; Silberman, Jeffrey ; Brown, M.W. ; Pearce, R.A. ; Tice, A.K. ; Jousset, A. ; Geisen, Stefan ; Hartikainen, Hanna - \ 2016
Environmental Microbiology 18 (2016)5. - ISSN 1462-2912 - p. 1604 - 1619.
A wide diversity of organisms utilize faecal habitats as a rich nutrient source or a mechanism to traverse through animal hosts. We sequenced the 18S rRNA genes of the coprophilic, fruiting body‐forming amoeba Guttulinopsis vulgaris and its non‐fruiting relatives Rosculus ‘ithacus’ CCAP 1571/3, R. terrestris n. sp. and R. elongata n. sp. and demonstrate that they are related to the coprophilic flagellate Helkesimastix in a strongly supported, but highly divergent 18S sister clade. PCR primers specific to both clades were used to generate 18S amplicons from a range of environmental and faecal DNA samples. Phylogenetic analysis of the cloned sequences demonstrated a high diversity of uncharacterised sequence types within this clade, likely representing previously described members of the genera Guttulinopsis, Rosculus and Helkesimastix, as well as so‐far unobserved organisms. Further, an Illumina MiSeq sequenced set of 18S V4‐region amplicons generated from faecal DNAs using universal eukaryote primers showed that core‐cercozoan assemblages in faecal samples are as diverse as those found in more conventionally examined habitats. These results reveal many novel lineages, some of which appear to occur preferentially in faecal material, in particular cercomonads and glissomonads. More broadly, we show that faecal habitats are likely untapped reservoirs of microbial eukaryotic diversity.
Indicatieve impact maatregelen zeebaars : eerste indicatie van de mogelijke impact van zeebaarsbeschermende maatregelen op de Nederlandse zeevisserij
Strietman, W.J. ; Weegh, J.B.M. op de - \ 2016
Wageningen : LEI Wageningen UR (Nota / LEI Wageningen UR 2016-007) - 23
zeebaars - zeevisserij - visserijbeheer - visbestand - bescherming - quota's - milieueffect - nederland - sea bass - marine fisheries - fishery management - fishery resources - protection - quotas - environmental impact - netherlands
Zeebaars paaigebieden en opgroeigebieden in Nederlandse wateren
Tulp, I.Y.M. ; Hal, R. van; Damme, C.J.G. van; Smith, S.R. - \ 2016
IMARES (Rapport / IMARES C060/16) - 35
visserijbeheer - zeevisserij - visserijbeleid - visbestand - habitatbeheer - nederland - het kanaal (english channel) - kuitschieten - waddenzee - zeeuwse eilanden - boomkorvisserij - zeebaars - noordzee - rijpen - fishery management - marine fisheries - fishery policy - fishery resources - habitat management - netherlands - english channel - spawning - wadden sea - zeeuwse eilanden - beam trawling - sea bass - north sea - maturation
De zeebaarspopulatie neemt sinds 2010 sterk af door een hoge visserij-inspanning en een lage aanwas van jonge zeebaars sinds 2008. Zeebaars is een langlevende soort die zich pas op latere leeftijd gaat voortplanten. Op een leeftijd van ca 4 jaar en met een lengte vanaf ca 42 cm (vrouwtjes) en 32 cm (mannetjes) beginnen ze paairijp te worden. De huidige minimum aanlandingsmaat van 42 cm heeft als gevolg dat veel vrouwtjes al gevangen worden voordat ze voor het eerst hebben kunnen paaien. Naast vangstbeperkende maatregelen wordt gezocht naar maatregelen ter bescherming van paai- en opgroeigebieden. Hiervoor is ecologische kennis nodig, die voor de Nederlandse wateren nog grotendeels ontbreekt. Aanwezigheid van paaiende volwassen zeebaarzen is direct bewijs voor een paaigebied. Het alternatief is om aan paaigebieden vast te stellen aan de hand van de verspreiding van eieren in een vroeg ontwikkelstadium. Een relatief groot aantal larven en juveniele zeebaars kan wijzen op het belang van een gebied als opgroeigebied. Aanbevelingen voor beleid Gezien de huidige staat van onze kennis, kunnen we nu geen steekhoudende aanbevelingen voor maatregelen gericht op bescherming van gebieden of habitats te geven. De evidentie voor paaigebieden is nog erg dun, de opgroeigebieden zijn wel redelijk bekend, maar over het relatieve belang van elk gebied voor de populatie is nog geen inzicht. Het is duidelijk dat overbevissing een probleem is gezien de ontwikkelingen in de aanlandingen en de afname in gemiddelde lengte bij aanlanding. Het is ook duidelijk dat de zeebaars die in Nederland gevangen wordt in ieder geval voor een groot deel afkomstig is uit het Kanaal en dat de visserij daar in het vroege voorjaar van grote invloed is op de hoeveelheid zeebaars, die later in het jaar in onze wateren terechtkomt. Op basis van de huidige gegevens en inzichten is een verdere inperking van de vangsten door zowel commerciële als recreatieve vissers in ieder geval een effectieve maatregel om de zeebaarsstand te vergroten. Of er in aanvulling daarop ook noodzaak is om gericht gebieden of habitats te beschermen of te verbeteren is met de huidige kennis en gegevens niet vast te stellen en kan alleen met aanvullend onderzoek worden vastgesteld.
Influence of water temperature on the economic value of growth rate in fish farming : The case of sea bass (Dicentrarchus labrax) cage farming in the Mediterranean
Besson, M. ; Vandeputte, M. ; Arendonk, J.A.M. van; Aubin, J. ; Boer, I.J.M. de; Quillet, E. ; Komen, H. - \ 2016
Aquaculture 462 (2016). - ISSN 0044-8486 - p. 47 - 55.
Bioeconomic model - Economic values - Fish farming - Genetic improvement - Temperature - Thermal growth coefficient
In sea cage farming, fish are exposed to seasonal variations of water temperature, and these variations can differ from one location to another. A small increase in water temperature does not only stimulate growth of the fish (until an optimal level) but also lowers dissolved oxygen concentration in water. Dissolved oxygen may then become a rearing constraint during the production cycle if the oxygen requirement of fish is higher than the supply. The impact of this constraint on production parameters (stocking density of cages and/or batch rotation) and thus on economic profit of a farm will depend on both local thermal regime and growth potential of the fish. Increased growth is one of the most important traits in a breeding objective to increase production capacity and profitability. We used a bioeconomic model of seabass reared in cages to calculate the economic value (EV) of increasing thermal growth coefficient (TGC) by selection in different conditions of average temperature (Tm) and amplitude of temperature variation (Ta). Tm and Ta values were taken from different locations in the eastern and western Mediterranean. Results show that increasing TGC has two consequences: (i) fast growing fish reach harvest weight earlier, which increases the number of batches that can be produced per year, and (ii) fast growing fish have higher daily feed intake and, consequently, higher daily oxygen consumption. To balance the oxygen demand and availability in a cage, a farmer might have to reduce the average stocking density, resulting in fewer fish produced per batch. Consequently, EV of TGC is positive when Tm is 19.5 °C or 21 °C, when an increase in number of batches produced compensates for the decrease in stocking density. EV of TGC is negative or null in areas where Tm is closer to 18 °C because the increase in number of batches produced cannot compensate for the decrease in stocking density. Our results show, for the first time, the importance of variation in ambient temperatures for breeding programs in fish. Statement of relevance: The economic impact of improving growth rate in sea cage farming system depends on temperature. This result is important for the development of breeding objectives maximizing economic return in fish breeding programs.