Effects of passive integrated transponder (PIT) implantation on Pacific lamprey ammocoetes

Mary L Moser,Aaron D Jackson,Alexa N Maine,Mary Davisson,Robert P Mueller

doi:10.1186/s40317-016-0118-3

Abstract

BackgroundLittle is known of the larval biology of Pacific lamprey (Entosphenus tridentatus), a species of conservation concern. With miniaturization of passive integrated transponder (PIT) tags, researchers now have the potential to individually mark larval lamprey. However, recent studies with sea lamprey (Petromyzon marinus) ammocoetes indicated that mortality was unacceptably high after surgical implantation of these tags. We examined survival, tag retention, growth, and swimming performance of Pacific lamprey ammocoetes tagged with uniquely coded 8.4-mm PIT tags and controls marked with visible implant elastomer (VIE).ResultsAmmocoetes as small as 71 mm in length were PIT-tagged. Of the 99 PIT-tagged individuals, four died (4%) and two lost their tags (2%) within 2 months of tagging. In this period, controls had 5% mortality and 15% VIE mark loss. Incisions were completely healed within 3 months of tagging, and mean specific growth rate during this period did not significantly differ between treatment groups. Ammocoetes bearing a PIT tag did not exhibit significant reductions in swimming performance relative to controls.ConclusionsWe attribute the success of this tagging effort to changes in tag implantation technique, including use of a lateral incision and no sutures. The ability to individually mark wild larval lamprey will allow research on individual growth rates, environmental effects on growth and metamorphosis, timing and rates of movement, and, ultimately, stage-specific survival.

Highlights

Little is known of the larval biology of Pacific lamprey (Entosphenus tridentatus), a species of conservation concern
Larval lamprey biology and ecology are poorly understood [1], in part due to the paucity of information on such basic topics as individual growth rates in nature, growth variation, range and timing of movements, and responses to environmental change. This information is needed for understanding and management of this group of fishes, in light of the fact that many lamprey species are of conservation concern [2, 3]
For fish held in the laboratory and 2.05 g (SD = 0.56) for fish held in the field

Summary

Introduction

Little is known of the larval biology of Pacific lamprey (Entosphenus tridentatus), a species of conservation concern. Larval lamprey (ammocoete) biology and ecology are poorly understood [1], in part due to the paucity of information on such basic topics as individual growth rates in nature, growth variation, range and timing of movements, and responses to environmental change. This information is needed for understanding and management of this group of fishes, in light of the fact that many lamprey species are of conservation concern [2, 3]. Tag loss and effects of 8.4-mm PIT tagging on small ammocoetes have not been evaluated for Pacific lamprey, a species of conservation concern

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