Mortality threshold for juvenile Chinook salmon Oncorhynchus tshawytscha in an epidemiological model of Ceratomyxa shasta

Diseases of Aquatic Organisms

Jerri L. Bartholomew¹  Philippe A. Rossignol¹  R. Adam Ray¹ 

关键词: Ceratomyxa shasta;    Epidemiological model;    Mortality threshold;    Chinook salmon;    Disease ecology;    Myxozoan;    Macroparasite;   

DOI  :  10.3354/dao02281

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: The myxozoan parasite Ceratomyxa shasta is a significant pathogen of juvenile Chinook salmon Oncorhynchus tshawytscha in the Klamath River, California, USA. This parasite requires 2 hosts to complete its life cycle: a freshwater polychaete (Manayunkia speciosa) and a salmonid. The complex life cycle and large geographic area where infection occurs make it difficult to monitor and manage ceratomyxosis. We present a model for ceratomyxosis-induced mortality in O. tshawytscha, from which parameters important to the persistence of C. shasta are identified. We also experimentally quantify specific parameters from the model and identify a mortality threshold (a critical parameter), by naturally exposing native O. tshawytscha to C. shasta in the Klamath River. The average percent mortality that resulted from these experimental challenges ranged from 2.5 to 98.5% over an exposure dose of 4.4 to 612 × 10⁶ parasites. This experiment identified a non-linear mortality threshold of 7.7 ± 2.1 × 10⁴ actinospores fish^–1 for Chinook salmon from the Iron Gate Hatchery on the Klamath River. Below this threshold no mortality occurred and above it mortality increased dramatically, thus providing a target by which to reduce parasitism in emigrating juvenile O. tshawytscha.

【 授权许可】

Unknown