PRIMARY MYCOSIS IN SHRIMP LARVAE

Larvae of the shrimp Palaemonetes kadiakensis have been reared in large numbers in the laboratory. Occasionally, the larvae would be attacked and killed by an aquatic fungus. Saprolegnia parasitica and Achlya flagellata were isolated from the shrimp and grown in pure culture. Using special techniques, embryos were incubated and hatched under sterile conditions providing germ-free larvae. Following preliminary experiments that demonstrated the infective nature of Saprolegnia parasitica on otherwise normal larvae, two kinds of experiments were conducted. The first involved inoculation of larvae on the day of hatching. In the second experiment, larvae were inoculated on the 3rd day immediately after completion of the first molt to Form II. All larvae developed severe localized infections and died as a result. The experiments conducted demonstrate that the infection of shrimp larvae is of a primary nature. A partially successful attempt to rear shrimp larvae on defined media is also described. © 1969.