The timing of changes in several internal organs during metamorphosis of anadromous larval lamprey Petromyzon marinus L.

1977 ◽  
Vol 55 (2) ◽  
pp. 469-473 ◽  
Author(s):  
J. H. Youson ◽  
G. M. Wright ◽  
E. C. Ooi

A current scheme for identification of stages in metamorphosis of sea lamprey Petromyzon marinus makes use of external features (Manion and Stauffer 1970). Of 13 larvae (ammocoetes) of anadromous sea lamprey sacrificed before they exhibited the earliest (stage 1) features of metamorphosis, 11 showed differentiation of the adult kidneys, and the beginnings of regression of the larval alimentary canal and endostyle. These changes are initiated not more than 1 month nor less than 1 week before known external signs are evident. There is a need for a reexamination and a further description of the early phases pf lamprey metamorphosis. Metamorphosis in anadromous sea lamprey provides excellent potential as an experimental system in comparative developmental biology.

1978 ◽  
Vol 56 (4) ◽  
pp. 561-570 ◽  
Author(s):  
I. C. Potter ◽  
G. M. Wright ◽  
J. H. Youson

A study has been made of metamorphosis in anadromous sea lampreys in New Brunswick between 1973 and 1976. The stages (1–7) commence with the recently described 'prometamorphic ammocoete' (Youson, J. H., G. M. Wright, and E. C. Ooi. 1977. The timing of changes in several internal organs during metamorphosis of anadromous larval lamprey Petromyzon marinus L. Can. J. Zool. 55: 469–473.) and conclude with one similar to the newly metamorphosed landlocked sea lamprey (Manion, P. J., and T. M. Stauffer. 1970. Metamorphosis of the landlocked sea lamprey, Petromyzon marinus. J. Fish. Res. Board Can. 27: 1735–1746.). Most of the marked quantitative changes exhibited by certain regions of the body can be directly related to adaptations for suctorial feeding, increased activity, and a predaceous mode of life. Reductions in the prebranchial length are almost certainly associated with changes in the pharyngeal basket which facilitate alterations in the direction of the respiratory water flow. The timing of metamorphosis was remarkably synchronous both within and between years, representatives of the earliest stages (1–2) being found only between July 7 and 28 while after September 14 only stage 7 animals were caught. During metamorphosis the lengths of the animals changed little whereas their weights declined significantly. The weights and condition factors of stage 1–2 animals were significantly greater than those of larvae of comparable length. This feature, presumably related to lipid accumulation at the end of larval life, is discussed in the context of factors influencing the onset of metamorphosis.


1974 ◽  
Vol 52 (12) ◽  
pp. 1585-1589 ◽  
Author(s):  
J. C. George ◽  
F. W. H. Beamish

The supraneural myeloid body of the sea lamprey (Petromyzon marinus) was studied in the feeding adult, late spawning run adult, and metamorphosing ammocoete. The fatty nature of the tissue was established by histochemical staining and electron microscopy. The presence of the fat cells and the actively differentiating blood cells evinced its similarity to the bone marrow in higher animals, thereby suggesting a phylogenetic affinity. In the late spawning run lampreys, the tissue was found to be almost empty of blood cells, leaving empty spaces within the stromal skeleton. In the feeding adult tissue, the various blood cell types differentiated from precursor cells have been identified. Megakaryoblasts possibly representing early phases of the cell type were observed only in the transforming (macrophthalmia stage) and adult lampreys. A marked active development of the tissue in the ammocoete was seen only at the fourth stage of the metamorphosing ammocoete immediately before macrophthalmia. At the macrophthalmia stage, the haematopoietic activity in the tissue increased substantially.


2009 ◽  
Vol 2009 (1) ◽  
pp. pdb.emo113-pdb.emo113 ◽  
Author(s):  
N. Nikitina ◽  
M. Bronner-Fraser ◽  
T. Sauka-Spengler

1980 ◽  
Vol 37 (11) ◽  
pp. 1989-2006 ◽  
Author(s):  
Everett Louis King Jr.

Criteria for the classification of marks inflicted by sea lamprey (Petromyzon marinus) into nine categories were developed from laboratory studies in an attempt to refine the classification system used in field assessment work. These criteria were based on characteristics of the attachment site that could be identified under field conditions by unaided visual means and by touching the attachment site. Healing of these marks was somewhat variable and was influenced by the size of lamprey, duration of attachment, severity of the wound at lamprey detachment, season and water temperature, and by other less obvious factors. Even under laboratory conditions staging of some wounds was difficult, especially at low water temperatures. If these criteria are to be used effectively and with precision in the field, close examination of individual fish may be required. If the feeding and density of specific year-classes of sea lampreys are to be accurately assessed on an annual basis, close attention to the wound size (as it reflects the size of the lamprey's oral disc) and character of wounds on fish will be required as well as consideration of the season of the year in which they are observed.Key words: sea lamprey, attack marks, lake trout, Great Lakes


2005 ◽  
Vol 70 (5) ◽  
pp. 1037-1045 ◽  
Author(s):  
Michael J. Siefkes ◽  
Scott R. Winterstein ◽  
Weiming Li

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