Pacific herring are known to lay their eggs on a wide variety of submerged vegetation, from algae to seagrass. A new study in the Marine Ecology Progress Series reports that Puget Sound herring show little preference when it comes to these types of spawning vegetation. The paper, co-authored by Puget Sound Institute Lead Ecologist Tessa Francis, analyzes herring egg loss on five types of vegetation in several herring subpopulations in Puget Sound. Authors include Andrew Shelton, Tessa Francis, Gregory Williams, Blake Feist, Kurt Stick and Phil Levin.
Nearshore habitats play a vital role in the life cycles of many marine fishes. These habitats are particularly important for Pacific herring Clupea pallasii, which rely on submerged vegetation in the shallow subtidal for spawning habitat and egg incubation. However, little is known about spatial or temporal variation in egg success or how spawning habitat may affect herring early life history. We estimated herring egg loss rates across multiple spawning vegetations in 5 subpopulations of Pacific herring in Puget Sound (USA), an urbanized estuarine system. We found enormous variation in herring egg loss among subpopulations (range of daily loss rates: 5 to 70%) and in egg loss of eggs reared under common garden conditions (range of cumulative loss: 20 to 100%). Egg loss varied by subpopulation but not by spawning vegetation type. Exploratory analyses suggest both wave height and land use patterns may affect hatch success. Using historical survey data, we found that a large proportion of spawning habitat available to Puget Sound herring remains unused each year. Furthermore, we found limited evidence that eggs were deposited disproportionally on particular vegetation types; only the non-indigenous brown algae Sargassum muticum was spawned on more than expected by chance. Our results demonstrate that Puget Sound herring are not limited by the amount of available suitable spawning vegetation, and that native vegetation is not preferred over other vegetation types for herring spawning. Rather, it appears that other terrestrial or marine variables are likely determinants of herring egg loss.
Shelton, Andrew O., Francis,Tessa B., Williams, Gregory D., Feist, Blake, Stick, Kurt, Levin. Phillip S. (2014). Habitat limitation and spatial variation in Pacific herring egg survival. Marine Ecology Progress Series. Vol. 514, pg. 231-245.