silvery white
By Jon Hare
shadbush blossoms
swim upstream
Shadbush (Amelanchier arborea) blooms in the spring. Clusters of small white flowers appear in March through May before leaves grow. The bloom time coincides with the upstream migration of American shad (Alosa sapidissima). Millions of shad used to return to east coast rivers, but these runs are now greatly reduced because of historical overfishing, dams, and loss of habitat.
Much like salmon, shad return to rivers to reproduce after several years at sea. Unlike salmon that reproduce and die, shad go back to sea after reproducing to return to rivers in following years to reproduce again. Thus salmon are termed semelparous from the Latin semel – once, a single time. Shad are termed iteroparous from the Latin itero – to repeat.
Shadbush is also iteroparous – blooming year after year in the spring to mark the return of the shad. Recent research by Nack et al. (2019) indicates shad migration will be earlier in the season; whether shadbush will bloom earlier remains to be seen.
Original research: https://doi.org/10.1002/mcf2.10076
Dr. Jon Hare is a scientist who works Woods Hole, Massachusetts. His research background is in fisheries oceanography and climate change impacts on marine fisheries. Check out Jon’s other sciku ‘Owls of the Eastern Ice’, ‘Varves’, ‘Cobwebs to Foodwebs’ and ‘Glacier Mice‘.