San Francisco Estuary mysid abundance in the fall, and the potential for competitive advantage of Hyperacanthomysis longirostris over Neomysis mercedis
Historically, the native mysid Neomysis mercedis was a key source of food for fish in the San Francisco Estuary (SFE). Following the introductions of the over-bite clam and many invasive zooplankton species in the mid-1980s, populations of native zooplankton species plummeted, including N. merced...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
California Department of Fish and Wildlife
2020-01-01
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| Series: | California Fish and Wildlife Journal |
| Subjects: | |
| Online Access: | https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=175915&inline |
| Summary: | Historically, the native mysid Neomysis mercedis was a key source of food
for fish in the San Francisco Estuary (SFE). Following the introductions of
the over-bite clam and many invasive zooplankton species in the mid-1980s,
populations of native zooplankton species plummeted, including N. mercedis.
In July 1993, Hyperacanthomysis longirostris, an invasive mysid, was first
documented in the SFE, and it quickly became the most abundant mysid in the
upper estuary. Since 2011, the California Department of Fish and Wildlife has
sampled mysid abundance throughout the upper SFE concurrently with their
Fall Midwater Trawl, which targets juvenile Striped Bass. We analyzed data
from these mysid trawls to investigate environmental correlates of N. mercedis
and H. longirostris abundance. We found that H. longirostris was found at
higher temperatures significantly more often than N. mercedis, and there was a
trend towards greater frequency of H. longirostris at higher salinities. Increases
in water temperature over time, coupled with H. longirostris’s smaller size at
maturity and lower food needs may partially explain its success in the SFE. |
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| ISSN: | 2689-419X 2689-4203 |