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Induction of metamorphosis in landlocked sea lampreys, Petromyzon marinus

1993; Wiley; Volume: 267; Issue: 6 Linguagem: Inglês

10.1002/jez.1402670607

1097-010X

John A. Holmes, John H. Youson,

Aquaculture disease management and microbiota

Abstract Landlocked larval sea lampreys ( Petromyzon marinus ) in three size‐groups were treated with two concentrations of potassium perchlorate (0.01 and 0.05% KC10 4 ; a goitrogen) for 117 days during the winter to determine if metamorphosis can be induced at a time when it will not occur spontaneously and whether a minimum size (length and weight) and physiological condition, measured as a condition factor (CF), are necessary for induction to occur. Metamorphosis was induced in all size‐groups with both concentrations of KC1O 4 but not in control animals. Size‐group was the only factor that significantly influenced ( P < 0.05) the incidence of metamorphosis, which was 22% (13/60) in the 65–95 mm group, 52% (31/60) in animals 110–119 mm long, and 98% (59/60) in animals >130 mm long. Metamorphosing animals were significantly larger ( P < 0.05) in size (length and weight) and had significantly higher ( P < 0.05) CFs than unmetamorphosed larvae. The mean (±SEM) CFs of metamorphosing animals in the three size‐groups were 1.22 ± 0.04 (65–95mm), 1.25 ± 0.02 (110–119 mm), and and 1.27 ± 0.02 (>130 mm) and the smallest animal to metamorphose was 84 mm and 0.71 g in size. Minimum size and CF criteria for spontaneous metamorphosis (120 mm, 3.0 g, 1.50 CF) in landlocked sea lampreys are not necessary prerequisites for inducing metamorphosis using KC1O 4 . The experimental production of metamorphosis in sea lampreys of various sizes creates a valuable tool for studying hormonal and genetic regulation of this developmental strategy in a vertebrate of ancient lineage. © 1993 Wiley‐Liss, Inc.