Recruitment ecology of burrowing shrimps in US Pacific coast estuaries

Authors: Dumbauld, Brett; BOSLEY, KATELYN - Oregon State University

Submitted to: Estuaries and Coasts - Journal of the Estuarine Research Federation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2018
Publication Date: 4/2/2018
Citation: Dumbauld, B.R., Bosley, K. 2018. Recruitment ecology of burrowing shrimps in US Pacific coast estuaries. Estuaries and Coasts - Journal of the Estuarine Research Federation. https://doi.org/10.1007/s12237-018-0397-4.
DOI: https://doi.org/10.1007/s12237-018-0397-4

Interpretive Summary: A series of surveys were made in two US West Coast estuaries to characterize recruitment and post-settlement processes for the last larval or decapodid stage and small juveniles of two species of burrowing shrimps, ghost shrimp(Neotrypaea californiensis) and mud shrimp (Upogebia pugettensis). A long term record suggested that this recruitment was highly variable from year to year and that there were important differences between species in seasonal timing of return of decapodids from the ocean to these coastal estuaries. On average mud shrimp settled earlier (April – July), recruited almost exclusively to areas where conspecific adult mud shrimp were present and grew more rapidly during their first summer than ghost shrimp. Ghost shrimp settled and recruited over a broader and mostly later period (June – November), were initially more abundant in areas where adult ghost shrimp were present, but settled broadly and appeared to survive and/or redistribute as small juvenile shrimp to areas where adults were absent. Linear relationships were found between the density of newly recruited (0+ age class) lagged one year and density of older 1+ shrimp and these relationships had positive slopes close to one for ghost shrimp and lower than one for mud shrimp which suggested that mud shrimp experienced higher mortality. Though annual recruitment varied dramatically, patterns in relative abundance were consistent amongst species and between the two estuaries, suggesting that both species of shrimp are part of larger multi- estuary metapopulations that are linked via larval dispersal. This has important implications for shrimp population management including control for shellfish aquaculture, but also conservation due to the important influence of these estuarine ecosystem engineers.

Technical Abstract: Recruitment has been shown to be a strong determinant of year class strength and adult population density especially for sessile benthic invertebrates where post settlement mortality and competition are low or relatively stable over time. We undertook a series of surveys to characterize recruitment and post-settlement processes for two species of burrowing shrimps, Neotrypaea californiensis and Upogebia pugettensis in order to determine how they influenced broader adult populations in US west coast estuaries. A long term record suggested that recruitment was highly variable from year to year and important interspecific differences in seasonal timing of return of decapodids from the ocean to these coastal estuaries. Results showed that on average U. pugettensis decapodids settled earlier (April – July), recruited almost exclusively to areas with conspecific adults, and grew more rapidly during their first summer than N. californiensis. N. californiensis decapodids settled and recruited over a later and broader period (June – November), were initially more abundant in areas where conspecific adults were present, but broadly distributed and appeared to survive and/or redistribute as small juvenile shrimp to areas where adults were absent. Linear relationships were found between newly recruited (0+ age class) lagged one year and that of older 1+ shrimp and had positive slopes close to one for N. californiensis and less than one suggesting lower survival for U. pugettensis. Though annual recruitment varied dramatically, patterns in relative abundance were broadly coherent amongst species and between estuaries, suggesting existence of larger multi- estuary metapopulations linked via larval dispersal. These have important implications for shrimp population management including control for shellfish aquaculture, but also conservation due to the strong influence of these estuarine ecosystem engineers.