Invasion
Invasion Description
1st Record: CA/Humboldt Bay (cultured, from 1953 to present; established?, Carlton 1979; Boyd et al. 2002)
'Oyster cultch is brought to Humboldt Bay from Puget Sound and is now placed on 'long lines' that keep the oysters suspended above the bottom of low intertidal mudflats in Arcata Bay. Grow-out takes 2-3 years before the oysters are of marketable size. In previous years 'ground culture' took place by scattering the cultch over the surface of the low mudflats that were built up by depositing waste oyster shell.' (Boyd et al. 2002). Sporadic reproduction was seen in 1962 and 1974 (Span 1978)
Geographic Extent
'Mad River Slough #1 and throughout oyster growing areas in Arcata Mad River Slough #1 and throughout oyster growing areas in Arcata (Boyd et al. 2002)
Vectors
| Level | Vector |
|---|---|
| Probable | Oyster Intentional |
Regional Impacts
| Economic Impact | Fisheries | |
| Magallana gigas is reared in extensive aquaculture operations in Humboldt Bay. These began in 1953 and continue to the present. About 90% of Calfornia's production occurred in Drakes Estero and Humboldt Bays (Conte 1996). | ||
| Ecological Impact | Parasite/Predator Vector | |
| Parasite-Predator vector- The introduction of M. gigas has been a possible/probable vector for a number of oyster foulers or predators in Humboldt Bay, including the parasitc copepod Mytilicola orientalis (widespread), the bryozoan Schizoporella japonica, and the tunicates Botrylloides violaceus, Didemnum vexillum and Styela clava (Carlton 1979; Boyd et al. 2002). | ||