3 July 2026. Just in time for America250 celebrations, we want to share our own small cause of joy and accomplishment. The team, NSF-REU student Gabe Redmon, graduate student Emma Siegfried, and Hannes Baumann, just finished the second and last experiment on Atlantic silverside embryo heat tolerance. The data will become part of a globally distributed experiment on fish embryo heat sensitivity (Thermal Ecology Alliance, P. Pottier), hopefully helping to reveal broader evolutionary and ecological patterns across taxa.

In the most work-intensive moments, the team could not have succeeded without the help of Hermione Lao (NSF-REU 2026), graduate students Vicky You & Hannah Roby, and Hiryu Shinand (undergrad). Thank you!

The general experimental design was straightforward to make it broadly adaptable across systems. The goal was to expose newly fertilized fish embryos to heat stress and quantify their mortality. Choose a presumed stressful range of temperatures, vary the duration of the exposure, assess it at two developmental stages (early vs. advanced). Generally, silversides make great model organisms; they have been studied for decades and repeatedly rose to fame for revealing novel eco-evoluationary patterns (e.g., Conover, Therkildsen et al., Akopyan et al., Murray et al.).

However, the thermal sensitivity of Atlantic silverside embryos had not yet been robustly quantified.

The project is a central part of Gabe Redmon's NSF-sponsored Research Experience for Undergraduates (REU, UConn-MysticAquarium, NSF #2349353). Gabe discovered early that 'straightforward' does not equal 'easy' or 'low effort'. First lesson; silversides don't particularly care about Mo-Fr schedules, they are on a moon schedule, which influences the tides. For good quality experiments, it is best to collect adults right before they spawn on full and new moons. And with all the events that than need to follow in short order; there simply is no way to avoid weekends. Luckily, Gabe was completely unflinched by any of that; his dedication and curiosity were outstanding. Together, we designed some novel rearing designs to allow tracking groups off embryos through hatching. Together, we went to Mumford Cove to collect spawning-ripe adults with a beachseine. Twice.

Together - and with the necessary portion of luck - we pulled it off.

The time to show you the data will come later, the time to show some pictures is now. The analysis, which turns numbers into patterns, which then may lead to new insights has only just begun. One thing, however, is already clear from these data; silverside embryos are surprisingly heat stress tolerant. Exposures of up to 4h to 27-34C produced no measurable increase in mortality.

But that's not the whole story. There is more to come.

For now, join me again in a big show of hands for the whole team and the many helping hands!