Stream characteristics associated with feeding type in silver(Ichthyomyzon unicuspis) and northern brook (I. fossor) lampreys and tests for phenotypic plasticity

Environmental Biology of Fishes
By: , and 

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Abstract

In most lamprey genera, “paired” species exist in which the larvae are morphologically indistinguishable but adult feeding type differs. The lack of diagnostic genetic differences in many pairs has led to suggestions that they constitute a single gene pool with environmentally influenced feeding types. To investigate whether stream characteristics are correlated with feeding type in the parasitic silver lamprey Ichthyomyzon unicuspis and nonparasitic northern brook lamprey I. fossor, eight variables (pH, alkalinity, conductivity, discharge, total dissolved solids, and density of larval sea lamprey Petromyzon marinus, Ichthyomyzon spp., and total larval density) were compared among eight streams with only silver lamprey, 10 with only northern brook lamprey, and 13 with both species, using classification tree analysis. The most parsimonious model had a 24% misclassification rate, with silver lamprey tending to inhabit streams with higher sea lamprey larval density and northern brook lamprey tending to inhabit streams with higher Ichthyomyzon larval density. We then conducted a pilot study investigating phenotypic plasticity in a lab-based common garden experiment and an in situ transplant experiment. These studies encountered myriad difficulties and were unable to demonstrate plasticity, but did identify challenges associated with culturing Ichthyomyzon larvae. Development of effective rearing procedures for Ichthyomyzon lampreys is essential for any future similar studies.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Stream characteristics associated with feeding type in silver(Ichthyomyzon unicuspis) and northern brook (I. fossor) lampreys and tests for phenotypic plasticity
Series title Environmental Biology of Fishes
DOI 10.1007/s10641-019-00857-8
Edition Online First
Year Published 2019
Language English
Contributing office(s) Great Lakes Science Center
Country Canada, United States
Other Geospatial Great Lakes, Lake Champlain basin