Preliminary Report on the Fecundity of Mytilicola orientalis

1969 ◽  
Vol 26 (8) ◽  
pp. 2245-2246
Author(s):  
Eugene A. Johnson ◽  
Kenneth K. Chew
Keyword(s):  
Mytilus Edulis ◽  
Crassostrea Gigas ◽  
Preliminary Report ◽  
Willapa Bay ◽  
Individual Female ◽  
Hood Canal ◽  
Pacific Oysters

Egg cases of the endoparasitic copepod Mytilicola orientalis Mori were examined from samples dissected from Pacific oysters (Crassostrea gigas) and bay mussels (Mytilus edulis) from Humboldt Bay, California, Yaquina Bay, Oregon, and Willapa Bay and Hood Canal, Washington. There was little variation between the number of eggs in both egg cases from an individual female. On the bases of two egg sacs per female approximately 252–368 eggs are produced.

scholarly journals Electrophysiological Evaluation of Pacific Oyster (Crassostrea gigas) Sensitivity to Saxitoxin and Tetrodotoxin

Marine Drugs ◽  
2021 ◽  
Vol 19 (7) ◽  
pp. 380
Author(s):  
Floriane Boullot ◽  
Caroline Fabioux ◽  
Hélène Hégaret ◽  
Pierre Boudry ◽  
Philippe Soudant ◽  
...  
Keyword(s):  
Crassostrea Gigas ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Alexandrium Minutum ◽  
Paralytic Shellfish Toxins ◽  
Pacific Oysters ◽  
Paralytic Shellfish ◽  
Good Potential ◽  
First Time ◽  
Micromolar Range

Pacific oysters (Crassostrea gigas) may bio-accumulate high levels of paralytic shellfish toxins (PST) during harmful algal blooms of the genus Alexandrium. These blooms regularly occur in coastal waters, affecting oyster health and marketability. The aim of our study was to analyse the PST-sensitivity of nerves of Pacific oysters in relation with toxin bio-accumulation. The results show that C. gigas nerves have micromolar range of saxitoxin (STX) sensitivity, thus providing intermediate STX sensitivity compared to other bivalve species. However, theses nerves were much less sensitive to tetrodotoxin. The STX-sensitivity of compound nerve action potential (CNAP) recorded from oysters experimentally fed with Alexandrium minutum (toxic-alga-exposed oysters), or Tisochrysis lutea, a non-toxic microalga (control oysters), revealed that oysters could be separated into STX-resistant and STX-sensitive categories, regardless of the diet. Moreover, the percentage of toxin-sensitive nerves was lower, and the STX concentration necessary to inhibit 50% of CNAP higher, in recently toxic-alga-exposed oysters than in control bivalves. However, no obvious correlation was observed between nerve sensitivity to STX and the STX content in oyster digestive glands. None of the nerves isolated from wild and farmed oysters was detected to be sensitive to tetrodotoxin. In conclusion, this study highlights the good potential of cerebrovisceral nerves of Pacific oysters for electrophysiological and pharmacological studies. In addition, this study shows, for the first time, that C. gigas nerves have micromolar range of STX sensitivity. The STX sensitivity decreases, at least temporary, upon recent oyster exposure to dinoflagellates producing PST under natural, but not experimental environment.

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