An Agent Based Model of the Diel Vertical Migration Patterns of Mysis diluviana

Recent work indicates that the macro-invertebrate Mysis diluviana exhibits partial diel vertical migration (DVM), whereby one part of the population remains on the lake bottom at night while the other migrates up the water column. The drivers underlying the decision to migrate remain unknown. We developed an agent-based model that can simulate thousands of individual mysids decision-making processes at an hourly time step throughout a year. The model takes into account a daily and seasonally changing environment, including light, temperature, food availability across habitats and body con- dition. We found that the simulated Mysis population is highly sensitive to changes in the energy cost of performing migration. We have also devel- oped a graphical user interface to help disseminate the results and testing of hypotheses without the need for the researcher to edit code. In addition to testing hypotheses about migration drivers, the model, once parameters have been calibrated with real data, will help facilitate more efficient field sampling and prediction of resource availability for mysivorous fishes by evaluating the potential for seasonality in Mysis migration patterns

Competition for the fish - fish extraction from the Baltic Sea by humans, aquatic mammals and birds

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Fiskaren och fisken

Fiskaren och fisken Innehållsförteckning – Inledaren: Ett försvinnande kulturarv av Pia Prost – Välmående skärgård tack vare strömmingen av Anne Bergström – Vinternotdragningen – sörjd, saknad av Nina Söderlund – Nationella och internationella bestämmelser kring fiske av Kaj Mattsson – 130 år av fiskerirådgivning av Malin Lönnroth – Sista Sibbofiskaren satsar på förädling av Thure Malmberg – Fisket i Skärgårdshavet i konstant förändring av Pekka Salmi, Kristina Svels och Jari Setälä – Ett arbetsliv i fiskenäringens tjänst – Kari Ranta-aho går i pension av Pia Prost – Inhemskt fiskfoder bra för både fiskerinäringen och havet av Pia Prost – Vasa fick sitt Fiskets hus av Guy Svanbäck – Förlorar vi en primärnäring? av Kaj Mattsson – Konkurrens om fisken – människa, säl och skarv av Sture Hansson – Allt hänger på en god fiskeförvaltning av Cecilia Lundberg – Aktuell fiskforskning vid Åbo Akademi av Martin Snickars och Tom Wiklund – Historiska hamnplatser och fiskelägen kartläggs av Tapani Tuovinen och Riikka Tevali – Gråsälen är kustfiskets gissel av Mia Henriksson – Hur uppfattar fiskarna sin omvärld? av Marina Saanila Bokhörnan: – Gäddan, Nordens krokodil av Nalle Valtiala – Ålevangeliet: berättelsen om världens mest gåtfulla fisk av Cecilia Lundberg – Är Åland skärgårdssamhällenas paradis? av John Wrede – Skärgården diskuterade FN:s hållbarhetsmål av Pia Prost – Skärinytt – Sista bilde

Increased Expression of Cannabinoid CB1 Receptors in Achilles Tendinosis

BACKGROUND: The endogenous cannabinoid system is involved in the control of pain. However, little is known as to the integrity of the cannabinoid system in human pain syndromes. Here we investigate the expression of the cannabinoid receptor 1 (CB₁) in human Achilles tendons from healthy volunteers and from patients with Achilles tendinosis. METHODOLOGY: Cannabinoid CB₁ receptor immunoreactivity (CB₁IR) was evaluated in formalin-fixed biopsies from individuals suffering from painful Achilles tendinosis in comparison with healthy human Achilles tendons. PRINCIPAL FINDINGS: CB₁IR was seen as a granular pattern in the tenocytes. CB₁IR was also observed in the blood vessel wall and in the perineurium of the nerve. Quantification of the immunoreactivity in tenocytes showed an increase of CB₁ receptor expression in tendinosis tissue compared to control tissue. CONCLUSION: Expression of cannabinoid receptor 1 is increased in human Achilles tendinosis suggesting that the cannabinoid system may be dysregulated in this disorder

Behavioral, ecological and genetic differentiation in an open environment--a study of a mysid population in the Baltic Sea.

Diel vertical migration (DVM) is often assumed to encompass an entire population. However, bimodal nighttime vertical distributions have been observed in various taxa. Mysid shrimp populations also display this pattern with one group concentrated in the pelagia and the other near the bottom. This may indicate alternative migratory strategies, resembling the seasonal partial migrations seen in birds, fishes and amphibians, where only a subset of the population migrates. To assess the persistence of these alternative strategies, we analyzed the nitrogen and carbon stable isotope signatures (as proxies for diet), biochemical indices (as proxies for growth condition), and genetic population divergence in the Baltic mysid Mysis salemaai collected at night in the pelagia and close to the bottom. Stable isotope signatures were significantly different between migrants (pelagic samples) and residents (benthic samples), indicating persistent diet differences, with pelagic mysids having a more uniform and carnivorous diet. Sequencing of the mitochondrial cytochrome subunit I (COI) gene showed genetic differentiation attributable to geographic location but not between benthic and pelagic groups. Divergent migration strategies were however supported by significantly lower gene flow between benthic populations indicating that these groups have a lower predisposition for horizontal migrations compared to pelagic ones. Different migration strategies did not convey measurable growth benefits as pelagic and benthic mysids had similar growth condition indices. Thus, the combination of ecological, biochemical and genetic markers indicate that this partial migration may be a plastic behavioral trait that yields equal growth benefits