Species distribution models as a tool for early detection of the invasive Raphidiopsis raciborskii in European lakes

In freshwater habitats, invasive species and the increase of cyanobacterial blooms have been identified as a major cause of biodiversity loss. The invasive cyanobacteria Raphidiopsis raciborskii a toxin-producing and bloom-forming species affecting local biodiversity and ecosystem services is currently expanding its range across Europe. We used species distribution models (SDMs) and regional bioclimatic environmental variables, such as temperature and precipitation, to identify suitable areas for the colonization and survival of R. raciborskii, with special focus on the geographic extent of potential habitats in Northern Europe. SDMs predictions uncovered areas of high occurrence probability of R. raciborskii in locations where it has not been recorded yet, e.g. some areas in Central and Northern Europe. In the southeastern part of Sweden, areas of suitable climate for R. raciborskii corresponded with lakes of high concentrations of total phosphorus, increasing the risk of the species to thrive. To our knowledge, this is the first attempt to predict areas at high risk of R. raciborskii colonization in Europe. The results from this study suggest several areas across Europe that would need monitoring programs to determine if the species is present or not, to be able to prevent its potential colonization and population growth. Regarding an undesirable microorganism like R. raciborskii, authorities may need to start information campaigns to avoid or minimize the spread.publishedVersio

Sperm competition in yellow dung flies: No consistent effect of sperm size

The male competition for fertilization that results from female multiple mating promotes the evolution of increased sperm numbers and can impact sperm morphology, with theory predicting that longer sperm can at times be advantageous during sperm competition. If so, males with longer sperm should sire more offspring than competitors with shorter sperm. Few studies have directly tested this prediction, and findings are inconsistent. Here we assessed whether longer sperm provide a competitive advantage in the yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Initially, we let brothers with different temperature-mediated mean sperm lengths compete – thus minimizing confounding effects of genetic background – and found no clear advantage of longer sperm. We then used flies from lines subjected to bidirectional selection on phenoloxidase activity that had shown correlated evolutionary responses in sperm and female spermathecal duct lengths. This experiment also yielded no main effect of sperm size on siring success. Instead, there was a trend for a shorter-sperm advantage, but only when competing in females with longer spermathecal ducts. Our data corroborated many previously reported findings (last-male precedence, effects of copula duration and body size), suggesting our failure to find sperm size effects is not inherently due to our experimental protocols. We conclude that longer sperm are not competitively superior in yellow dung flies under most circumstances, and that, consistent with previous work, in this species competitive fertilization success is primarily determined by the relative numbers of sperm competing

Can fisheries-induced evolution shift reference points for fisheries management?

Heino, M., Baulier, L., Boukal, D. S., Ernande, B., Johnston, F. D., Mollet, F. M., Pardoe, H., Therkildsen, N. O., Uusi-Heikkilä, S., Vainikka, A., Arlinghaus, R., Dankel, D. J., Dunlop, E. S., Eikeset, A. M., Enberg, K., Engelhard G. H., Jørgensen, C., Laugen, A. T., Matsumura, S., Nusslé, S., Urbach, D., Whitlock, R., Rijnsdorp, A. D., and Dieckmann, U. 2013. Can fisheries-induced evolution shift reference points for fisheries management? - ICES Journal of Marine Science, 70: 707-721. Biological reference points are important tools for fisheries management. Reference points are not static, but may change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting” reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true” reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and "precautionary” reference points for spawning-stock biomass, Blim and Bpa, and the target reference point for fishing mortality, F0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamic

Can fisheries-induced evolution shift reference points for fisheries management?

Biological reference points are important tools for fisheries management. Reference points are not static, butmay change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting" reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true" reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and "precautionary" reference points for spawning-stock biomass, B-lim and B-pa, and the target reference point for fishing mortality, F-0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamics

Høsting av stillehavsøsters

Denne rapporten utreder sentrale spørsmål og fagområder knyttet til høsting av stillehavsøsters, som fremmed art og ny ressurs. Arten har etablert seg i nordiske kystfarvann. Den er regnet som invasiv og tette bestander kan føre til endringer i økosystemet. Arten kan ikke utryddes, og ryddekampanjer har kun lokal og tidsbegrenset effekt. Fjernede østers bør brukes, som mat, fôr eller industriprodukt, slik at vi sikrer en god ressursutnyttelse. Vi trenger kunnskap om stillehavsøstersens effekt på økosystemet, utbredelse og effektene av høsting og rydding. Som grunnlag for høsting og bruk er det behov for avklaring av juridiske forhold og etablering av en hensiktsmessig forvaltningspraksis. Kontroll av mattryggheten må også på plass. I næringsutviklingen ser vi for oss et samspill mellom ulike sektorer, som salg av lokale østers og østersprodukter, turisme, restaurantnæring og overnatting

Knowledge base for informed management of OSPAR-listed Mytilus and Ostrea beds. Part 2 - Methods for restoration and protection of Mytilus and Ostrea beds

Tvåskaliga blötdjur (bivalver) som blåmusslor (Mytilus edulis) och ostron (Ostrea edulis) är nyck-elarter i kustekosystem och de bidrar både till ökad biologisk mångfald genom att skapa livsmiljöer för andra organismer och till flera andra viktiga ekosystemtjänster. Under de senaste åren har både Mytilus- och Ostrea-bankar minskat i antal och omfattning i Europa, och det finns också starka indikationer på en liknande situation för Mytilus i Sverige. För Ostrea saknas generellt kunskap om populationsstorlekar, vilket gör bedömningar av populationsutveckling problema-tisk. Bevarandeåtgärder som beståndsförstärkning och -restaurering ökar därför i omfattning allt eftersom biodiversitet förloras, och det finns ett växande intresse för att återställa habitat skap-ade av musslor och ostron på många platser i världen. Den hotbildsanalys som genomförts av OSPAR för Mytilus- och Ostrea-bankar i Europa indikerar att den primära orsaken till förlust av bivalvbankar i Europa är överexploatering och habitatför-lust, samt sjukdomsutbrott orsakade av patogener. Svenska bivalvbestånd är dock mer eller mindre förskonade från dessa påverkansfaktorer. Andra faktorer kan dock också påverka populationsutvecklingen. Till exempel finns det en oro bland förvaltande myndigheter att det invasiva stillahavsostronet kommer att försämra förutsättningarna för livskraftiga bestånd av Mytilus och Ostrea i Sverige. Sammantaget finns det goda skäl till att utforska vilka möjliga alternativ som finns för förstärkning av Mytilus- och Ostrea-populationerna och vilka metoder som skulle kunna användas om stillahavsostron visar sig vara ett hot mot våra inhemska bivalvpopulationer. Syftet med detta projekt var därför att ta fram ett kunskapsunderlag för utformning av förvaltningsmodeller för skydd av Sveriges populationer av Mytilus och Ostrea. En del i detta arbete utgörs av kunskaps-byggande kring möjliga åtgärder kopplat mot restaurering av bivalvbankar genom till exempel bortrensning av stillahavsostron ur bivalvbankar eller beståndsförstärkning. Sammanfattningsvis genomfördes ett antal olika aktiviteter som redovisas i denna rapport, bland annat ett rensningsförsök i vilket stillahavsostron avlägsnades ur både Mytilus- och Ostrea-bankar, ett beståndsförstärkningsförsök med Ostrea i vilket yngel av Ostrea placerades på olika lokaler, och flera olika studier rörande beståndsförstärkning av Mytilus, bland annat inklu-derande studier av biologiska förutsättningar och metodik kring beståndsförstärkning. Rensningsförsöken visade att det var möjligt att rensa bort stillahavsostron ur bivalvbankar men att detta är tidskrävande och komplicerat, speciellt i samband med Mytilus-bankar. Effekten av rensningen var kortvarig avseende antal stillahavsostron, redan ett år efter rensningsinsatsen var antalet stillahavsostron likvärdigt med antalet före rensningen. Återkoloniseringen skiljde sig åt mellan lokaler, men vilka faktorer som påverkade återkoloniseringen är inte klarlagt. Biomassan av stillahavsostron var på flera av försökslokalerna inte i nivå med före rensningsinsatserna vid projektets slut. Bättre tekniker behöver utvecklas för mer resurseffektiva insatser om denna typ av aktivitet ska genomföras regelbundet. Metoder för att ta hand om skördad biomassa av stillahavsostron behöver också utvecklas. Beståndsförstärkningsförsöken visade också de på att det var möjligt att återetablera bivalvbankar på pilotskala. Även på lokaler med goda förhållanden kommer dock målarten att minska efter utläggning. I försöken var till exempel överlevnaden av Ostrea (ca 30-50 mm längd vid ut-läggning) på den bästa lokalen ca 16 procent efter 2 år, och för Mytilus minskade täckningsgra-den av råmussla (dvs. en blandning av stora och små musslor) med nästan 50 procent på ett år och överlevnaden var ca 20 procent under samma period. Generellt observerades predation vara ett problem för båda arterna. Små och mellanstora Mytilus påverkades mycket av ejder, medan krabbor orsakade hög dödlighet för Ostrea. Lokalspecifika förhållanden var också av stor betydelse för försökens framgång. Exempel på faktorer som diskuteras i denna rapport är förutom förekomst av predatorer också isläggning, substrat, möjlighet till inflyttning av organismer för restaureringsförsök/aktiviteter, djup och exponering. Det är tydligt att mycket är att vinna på ett gediget förarbete innan beståndsförstärkningsaktiviteter initieras. Erfarenheterna från projektet visar också på vikten av skydd mot exploatering av de restaurerade bestånden samt en god relat-ion till myndigheter och markägare. En unik aktivitet i projektet som, till vår vetskap, inte testats tidigare är nyttjandet av restmuss-lor från kommersiell musselproduktion för beståndsförstärkning av Mytilus. Genom att använda spillmusslor skapas ökad cirkularitet och förbättrat resursutnyttjande inom vattenbruksproduktionen, samt att både ekologiska och ekonomiska vinster erhålls då viktiga naturmiljöer återskapas samtidigt som vattenbruksföretagen får minskade kostnader för deponi av spill från produktionen. Det kvarstår dock att utreda hur omfattande denna typ av aktivitet kan bli, då målet inom musselodlingen naturligtvis är att producera en produkt utan påväxt. I tillägg måste reglerings-mässiga förutsättningar för denna typ av nyttjande utredas. Slutligen diskuteras i rapporten ett antal utvecklingsområden som bör utredas vidare inför fram-tida beståndsförstärkningsförsök. Sammantaget kan konstateras att ett fortsatt arbete med att följa upp pågående studier och att övervaka restaureringsframgång, att identifiera kriterier för urval av lokaler, att hitta lokalt optimerade tekniker för restaurering, samt att kvantifiera de ekosystemtjänster som dessa bivalvbankar potentiellt kan bidra med kommer att vara viktigt i arbetet framöver. En viktig del i detta är att dra lärdom av existerande kunskap men också att sätta in denna kunskap i en lokal kontext med målet att identifiera kunskapsluckor. Kombinerat kan dessa aktiviteter utgöra ett första steg mot att etablera en manual för restaurering av musslor och ostron i Sverige.Bivalve molluscs such as mussels (Mytilus edulis) and oysters (Ostrea edulis) are key species in coastal ecosystems, and contribute to increased biodiversity by creating habitats for other organ-isms and to several other important ecosystem services. In recent years, both Mytilus- and Os-trea-beds have been reported to be in decline in Europe, and there are strong indications of a similar situation also for Mytilus in Sweden. For Ostrea, there is a general lack of knowledge about population sizes, which makes assessments of population development problematic. Conservation measures such as stock enhancement and restoration are therefore increasing as biodiversity is lost, and there is a growing interest in restoring habitats created by mussels and oysters in many parts of the world. The threat analysis carried out by OSPAR for Mytilus- and Ostrea-beds in Europe indicates that the primary cause of loss of bivalves in Europe is overexploitation and habitat loss, as well as disease outbreaks caused by pathogens. The Swedish bivalve populations, however, are more or less spared from these impact factors. Nevertheless, other factors can also affect population de-velopment. For example, there is concern among management authorities that the invasive Pacific oyster may impact the populations of Mytilus and Ostrea in Sweden negatively. All in all, there are good reasons to explore the possible alternatives for supporting the development of the Mytilus- and Ostrea-populations, and also methods that could be used if the Pacific oyster prove to impact the native bivalve populations negatively. The purpose of this project was therefore to produce a knowledge base for the establishment of management models for the pro-tection of Sweden's populations of Mytilus and Ostrea. Part of this work include knowledge building, both theoretical and practical, about possible restoration measures of bivalve beds, e.g. removal of Pacific oysters or stock enhancement. To summarise, a number of performed activities are discussed in this report, including a removal experiment in which Pacific oysters were removed from both Mytilus- and Ostrea-beds, a stock enhancement experiment with Ostrea in which juveniles of Ostrea were placed on different sites, and several different studies on stock enhancement of Mytilus, including studies of biological conditions and methodology for population enhancement. The removal experiments demonstrated that it was possible to clear Pacific oysters from bivalve beds but that this is time consuming and complicated, especially in Mytilus beds. In terms of numbers of oysters the effect of the removal was short-lived. Already one year after the removal, the number of Pacific oysters was equal, or higher, to the number before the experiment. In terms of biomass, however, many of the cleared sites did not show complete recovery och the biomass of the invasive species. How long the recolonization time was before the original biomass was re-established is unknown, but calculations indicate that this time is longer than for the abundance of oysters. Better technologies must be developed for more resource-efficient efforts if this type of activity is to be carried out regularly. Additionally, ways to utilize the harvested biomass of Pacific oysters must be established. The stock enhancement experiments also showed that it was possible to re-establish bivalve beds on a pilot scale. Even in sites with good conditions, however, the target species will decrease after relaying. In the experiments performed, the survival of Ostrea (about 30-50 mm in length when re-laid) on the best sites was only about 16% after 2 years, and for Mytilus the cover of mussels (a mixture of large and small mussels) decreased by almost 50% in one year and the survival was about 20% after this period of time. In general, predation was observed to be a problem for both species. Small and medium-sized Mytilus were greatly affected by eider duck, while shore crabs caused high mortality for Ostrea. Site-specific conditions were also of great importance for the success of the experiments. Examples of factors discussed in this report are, in addition to the presence of predators, also ice-cover, substrate, the possibility of moving in organisms for resto-ration experiments/activities, depth and exposure. It is obvious that much can be gained from solid preparatory work before stock enhancement activities are initiated. The experiences from the project also illustrate the importance of protection against exploitation of the restored populations and a good relationship with authorities and landowners. A unique activity in the project that, to our knowledge, has not been tested before is the use of residual mussels from commercial mussel production for stock enhancement of Mytilus. By using waste mussels, increased circularity and improved resource utilization in aquaculture produc-tion can be achieved, with both ecological and economic gains as important natural environments are recreated and costs for waste management from production is reduced for the aquaculture companies. However, it remains to be explored how extensive this type of activity can be as the goal in mussel farming is, of course, to produce a product without fouling. In addition, the regulatory conditions for this type of use must be established.Finally, the report discusses a number of development needs that should be studied further be-fore future stock enhancement experiments. Among these aspects, monitoring of ongoing activi-ties and success rate of restoration should be implemented, guidelines for site selection should be established, optimized techniques for restoration adapted to local conditions should be devel-oped, and the ecosystem services that the bivalve beds can support should be documented in future work. An important part of this is to learn from existing knowledge but also to put this knowledge into a local context with the goal of identifying important knowledge gaps for context relevant activities. Combined, these activities can be a first step towards establishing a manual for the restoration of mussels and oysters in Sweden.C370</p

Species distribution models as a tool for early detection of the invasive Raphidiopsis raciborskii in European lakes

In freshwater habitats, invasive species and the increase of cyanobacterial blooms have been identified as a major cause of biodiversity loss. The invasive cyanobacteria Raphidiopsis raciborskii a toxin-producing and bloom-forming species affecting local biodiversity and ecosystem services is currently expanding its range across Europe. We used species distribution models (SDMs) and regional bioclimatic environmental variables, such as temperature and precipitation, to identify suitable areas for the colonization and survival of R. raciborskii, with special focus on the geographic extent of potential habitats in Northern Europe. SDMs predictions uncovered areas of high occurrence probability of R. raciborskii in locations where it has not been recorded yet, e.g. some areas in Central and Northern Europe. In the southeastern part of Sweden, areas of suitable climate for R. raciborskii corresponded with lakes of high concentrations of total phosphorus, increasing the risk of the species to thrive. To our knowledge, this is the first attempt to predict areas at high risk of R. raciborskii colonization in Europe. The results from this study suggest several areas across Europe that would need monitoring programs to determine if the species is present or not, to be able to prevent its potential colonization and population growth. Regarding an undesirable microorganism like R. raciborskii, authorities may need to start information campaigns to avoid or minimize the spread

FemaleSurvival

Data for analysis of adult female survival as detailed in the Methods section of the paper. Variables are explained in the ReadMe file