Infestation by Brood Symbionts and Their Impact on Egg Mortality of the Red King Crab, Paralithodes camtschatica, in Alaska: Geographic and Temporal Variation

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Kuris, Armand M., Blau, S. Forrest, Paul, A. J., Shields, Jeffrey D., Wickham, Daniel E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1991
• Subjects: Kachemak; Red king crab; Alaska
• Online Access: http://dx.doi.org/10.1139/f91-071; http://www.nrcresearchpress.com/doi/pdf/10.1139/f91-071

Egg masses of 772 red king crab, Paralithodes camtschatica, were sampled to determine the prevalence, intensity, and patterns of cooccurrence of brood symbionts from 28 Alaskan localities. Carcinonemertes regicides and three other undescribed nemertean egg predators were recovered from many localities, as were an undescribed turbellarian and an amphipod, Ischyrocerus sp. A widespread outbreak of nemerteans occurred in the 1983–84 and 1984–85 red king crab brooding seasons. At some locations, nearly all of the eggs were consumed in the 1983–84 brood season. Feeding of C. regicides on eggs was documented in vitro and these worms caused substantial egg mortality at many locations. The amphipod was also an egg predator and may have had a significant impact at three locations. The turbellarian did not kill eggs. From the seasonal pattern of C. regicides infestation at Kachemak Bay, we postulate an abbreviated life cycle and autoinfection for C. regicides. Such life history features may have contributed to the peak intensities observed late in the 1983–84 and 1984–85 brooding seasons. At some localities, heavy brood mortality may reduce or eliminate recruitment of some year classes to the fishery.