A stage-structured model to predict the effect of temperature and salinity on glass eel Anguilla anguilla pigmentation development

The pigmentation development process of glass eels Anguilla anguilla from stage V-B to VIA3 was modelled by gamma cumulative functions. These functions varied with respect to the factors temperature and salinity whose effects were adjusted by beta functions. Temperature was shown to accelerate pigmentation, while salinity acted as a secondary factor slowing down the pigmentation. The model fits the development of 15 samples kept at various temperatures and salinities in the Vilaine River, as well as samples monitored at other dates and places in Europe. It allows the prediction of the duration of estuarine residency for glass eels, in winter and spring, in the Atlantic estuaries

What is metamorphosis?

Metamorphosis (Gr. meta- “change” + morphe “form”) as a biological process is generally attributed to a subset of animals: most famously insects and amphibians, but some fish and many marine invertebrates as well. We held a symposium at the 2006 Society for Integrative and Comparative Biology (SICB) annual meeting in Orlando, FL (USA) to discuss metamorphosis in a comparative context. Specifically, we considered the possibility that the term “metamorphosis” could be rightly applied to non-animals as well, including fungi, flowering plants, and some marine algae. Clearly, the answer depends upon how metamorphosis is defined. As we participants differed (sometimes quite substantially) in how we defined the term, we decided to present each of our conceptions of metamorphosis in 1 place, rather than attempting to agree on a single consensus definition. Herein we have gathered together our various definitions of metamorphosis, and offer an analysis that highlights some of the main similarities and differences among them. We present this article not only as an introduction to this symposium volume, but also as a reference tool that can be used by others interested in metamorphosis. Ultimately, we hope that this article—and the volume as a whole—will represent a springboard for further investigations into the surprisingly deep mechanistic similarities among independently evolved life cycle transitions across kingdoms

Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe

The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range