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

Heterogeneous natural selection on oxidative phosphorylation genes among fishes with extreme high and low aerobic performance

Background: Oxidative phosphorylation (OXPHOS) is the primary source of ATP in eukaryotes and serves as a mechanistic link between variation in genotypes and energetic phenotypes. While several physiological and anatomical factors may lead to increased aerobic capacity, variation in OXPHOS proteins may influence OXPHOS efficiency and facilitate adaptation in organisms with varied energy demands. Although there is evidence that natural selection acts on OXPHOS genes, the focus has been on detection of directional (positive) selection on specific phylogenetic branches where traits that increase energetic demands appear to have evolved. We examined patterns of selection in a broader evolutionary context, i.e., on multiple lineages of fishes with extreme high and low aerobic performance. Results: We found that patterns of natural selection on mitochondrial OXPHOS genes are complex among fishes with different swimming performance. Positive selection is not consistently associated with high performance taxa and appears to be strongest on lineages containing low performance taxa. In contrast, within high performance lineages, purifying (negative) selection appears to predominate. Conclusions: We provide evidence that selection on OXPHOS varies in both form and intensity within and among lineages through evolutionary time. These results provide evidence for fluctuating selection on OXPHOS associated with divergence in aerobic performance. However, in contrast to previous studies, positive selection was strongest on low performance taxa suggesting that adaptation of OXPHOS involves many factors beyond enhancing ATP production in high performance taxa. The broader pattern indicates a complex interplay between organismal adaptations, ATP demand, and OXPHOS function.This work was supported by NSF award DEB-0732988 (to REB).Ye

Explaining the effect of rapid internationalization on horizontal foreign divestment in the retail sector. An extended penrosean perspective

Building on and extending Penrosean logic we argue that rapid international expansion by firms might lead to a breach of Penrosean constraints on efficient expansion and to subsequent divestment of international operations to bring firm scope back into Penrosean constraints. We further predict that intra-regional concentration and international experience moderate the above effect because they influence firms ability to avoid a breach of Penrosean constraints and/or weaken the consequences of such a breach. Using data on the international expansion and divestment of large retail MNEs over the period 2003-2012 we find empirical support for the proposed extended Penrose effect in explaining international divestment as well as for the moderating effects of intra-regional concentration and international experience. Our study contributes to the development of Penrosean logic and to our understanding of the factors that drive firms to divest overseas operations

Product innovation in emerging market-based international joint ventures: An organizational ecology perspective

This study investigates product innovation in market-seeking international joint ventures (IJVs) in a large emerging market, and tests two sets of hypotheses: organizational orientation and environmental adaptation. Drawing on organizational ecology theory, we suggest that IJVs’ product innovation can be understood as a consequence of organizational orientation defined by IJV contract specifications and as a subsequent response to major contingencies of the local environment. Empirically, we analyzed a longitudinal dataset consisting of 3555 IJVs in China from 1999 to 2003, and found strong support for both sets of hypotheses. Product innovation in IJVs is positively associated with initial conditions such as balanced ownership structure, state partnership, and project size; IJVs are more innovative when they operate in an industry with a faster pace of innovation or a higher level of foreign direct investment legitimization, and where they are located in a region with greater agglomerated innovative activities. Journal of International Business Studies (2008) 39, 1114–1132. doi:10.1057/jibs.2008.51

Within-country product diversification and foreign subsidiary performance

We examine the product diversification of a multinational firm within each of its host-country markets. Based on a sample of 12,992 foreign subsidiaries of Japanese multinational firms, we find that higher levels of within-country product diversity led to higher subsidiary performance where the institutional strength of the local market was weak, and where a firm's corporate product diversity level was high. Our study highlights the importance of examining a multinational firm's strategy in its individual host-country markets, as influenced by the institutional characteristics of a host-country market and the corporate-level strategy of the multinational firm. Journal of International Business Studies (2008) 39, 706–724. doi:10.1057/palgrave.jibs.8400378