Laboratory rearing, growth, and bioenergetics of parasitic juvenile sea lamprey Petromyzon marinus
The behavior, physiology, growth, and bioenergetics of parasitic juvenile (non-metamorphosing) Sea Lamprey Petromyzon marinus (herein, juvenile) and its host fishes have been of interest since the Sea Lamprey invaded the Laurentian Great Lakes and contributed to the collapse of valued fisheries. However, questions concerning the ecology and control of Sea Lamprey remain unanswered because of difficulty in procuring juveniles from the wild and because there are few published methods for laboratory rearing that produce high survival of Sea Lamprey and their hosts. We describe methods developed to rear four Sea Lampreys from metamorphosis to the end of the juvenile feeding period in the laboratory using White Sucker Catostomus commersonii and Rainbow Trout Oncorhynchus mykiss as hosts. Wild-caught recently transformed juveniles fed on White Sucker ad libitum from their first feeding event starting in early May and continued feeding through July. From August through April of the following year, juveniles fed on Rainbow Trout for up to four days at a time and then were fasted for an average of 22 days (range 6–58 days) between feeding bouts. To evaluate if mass gain during short attachment bouts can be predicted, we applied a previously developed feeding model to data from 33 feeding bouts on Rainbow Trout. The feeding model was unbiased in predicting mass gained during short attachment bouts. Likewise, a bioenergetics model was unbiased in predicting mass loss during 29 fasting bouts. This report provides a protocol for humane rearing of juvenile Sea Lamprey and methods for predicting weight gain and loss for those conducting laboratory feeding experiments.