On Tuesday 25 February, Kalle Filipsson, RivEM PhD student, will give a seminar entitled ”From behaviour to genes: anti-predator responses of brown trout under winter conditions”. The seminar starts at 13.15 in room 5F416, everyone who wants to is welcome to attend the seminar.

This seminar is a practice seminar in preparation for Kalle’s (my) licentiate defense, which will be held Friday 13 March at 10:00. More information about the licentiate seminar will be provided closer to the defense.

Lea Schneider, Anders Nilsson, and Martin Österling from Karlstad University, recently published the scientific article “Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus” in the journal Hydrobiologia. In the article they present a study on the thick shelled river mussel (Unio crassus) and its release of glochidia (mussel larvae) in different temperature regimes.

In the abstract they write: “Adaptation to temperature regimes and host presence may enhance fitness in parasites. In an experimental study, we evaluated the timing of glochidia release by Unio crassus subjected to three spring water temperature regimes in the presence and absence of the host fish Cottus gobio. The timing of glochidia release was delayed at (i) constantly low temperatures (<10°C), in contrast to earlier and pronounced releases at (ii) natural temperature increases that level off at intermediate temperatures (10–15°C), and (iii) higher-than-normal temperatures (10–20°C). Mussels from treatment (i) that had not released glochidia during the experiment did so soon after being moved to the temperature in (ii), indicating a temperature threshold for glochidia release. Neither host fish presence nor the combined effect of temperature and host fish presence significantly affected the timing of glochidia release. The treatment with natural spring water temperatures indicated possible fitness benefits for U. crassus through combined effects of high intensities of glochidia releases and high survival of released glochidia. The furthered understanding of climate change effects on mussel and host phenology in seasonal environments, potentially inducing temporal mismatches of glochidia release to host availability, is key to mussel conservation.”

Acces the paper here: Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus

The research was part of the LIFE project UCforLIFE. Read more about the thick shelled river mussel and related conservation work at the projects homepage: www.ucforlife.se

Karlstad Universitet skriver om NRRV:s forskning om temperaturens betydelse under embryoutveckling hos vandrande fiskarters livscykel. I artiklen, med titeln Nordiskt samarbete ger forskningspengar skriver de:

Läs mer om Larry Greenberg’s forskning om vintertemperaturens effekt på fiskars utveckling, fysiologi och beteende i blogg-artikeln: Early environmental effects on behavior and growth: Atlantic salmon in an altered climate.

Larry Greenberg, professor within the River Ecology and Management research group at Karlstad University, is currently studying how increased winter temperatures may affect Atlantic salmon development and subsequent behavior and physiology. Here he describes his research, and shares two videos (one in autumn temperature and one in summer temperature) used to measure (count) ventilation rates on Atantic salmon parr:

“Embryonic temperature conditions are expected to affect an organism’s behavior, as behavior is linked to traits such as metabolic rate and growth. Examining the effects of embryonic temperature is particularly relevant in today’s society as unprecedented rates of climate change are predicted to occur during this century, with a larger temperature increase expected in winter than in summer. Hence, climate change will most likely have large effects on ectotherms (cold-blooded animals) that overwinter their eggs, as is the case for salmonid fishes. The aim of this project is to study the effects of water temperature during the egg stage on the behavior, growth and metabolic rate of juvenile Atlantic salmon.

When it concerns metabolic rates, I hypothesized that elevated temperature during the egg stage will result in reduced standard metabolic rates for juvenile brown trout. Instead of measuring metabolic rates, I have measured breathing rates (ventilation rate), which has been shown to be correlated with metabolic rates. This was done in darkness when breathing rates are lowest, using an infrared-sensitive camera. The two film clips below show two different fish, both of which were raised at cold ambient water temperatures as eggs. One fish was filmed in 7 ^oC water and the other at 18 ^oC water.”