Estimates of potential fish yield derived for the Lake Bangweulu system by three independent methods varied from 10 to 35 kg/hectare. An estimate of 20 kg/hectare predicted by the regression of yield on morphoedaphic index (MEI) for 31 African lakes is in good agreement with the 1973-1974 estimated yield of 19 kg/hectare. Potential yield was 35 kg/hectare in the morphoedaphic model for 17 intensively exploited African lakes. Potential yield based on primary production covariates was 16 kg/hectare. Standing crop estimates indicated possible yields of 10 to 17 kg/hectare based on 100% and 60% sampling recovery, respectively, of fish from chemical treatment samples and a 50% annual exploitation rate.

The early 20th-century French sociologist and philosopher Gabriel Tarde was an important critic of Durkheim's ontology of the social. Tarde developed a microsociological and ontological critique of the philosophical problems of resemblance and of variation underlying Durkheim's comparative sociology. Recently, thinkers such as Gilles Deleuze, Bruno Latour and Éric Alliez have begun to revisit Tarde and to develop a theme of the significance of Tarde's thought as a harbinger of postmodern theory. This article examines Tarde's theories in the light of this new reception. It is shown that Tarde draws heavily from Leibniz's theory of the quantitative continuity of qualitative singulars in order to critique Durkheim's statistics-based social realism. While some key limitations of Tarde's critique are exposed, it is argued that Tarde finds a way to remain faithful to statistical sociology as a project even while calling radically into question the qualitative unity of the social.

No abstract

This article argues that while modes of scholarship stressing structural insights into the digital divide and ethnographic insights into online communities each give us important information about current uses of the internet, for the sake of a unified social justice principle it is necessary to interpret these forms of knowledge in terms of what could be. Marx's formula 'the development of each as a condition for the development of all' is put forward as the principle of a socially-just internet actualized from the ground up. It is argued that the most rapidly emerging and important form of constraint upon 'the development of each' is the for profit online social media industry in which moments of human communicative creativity become packaged as commodities for commercial purposes. Creative, cultural agency becomes an imposition rather than a liberation as represented in the industry ideology. It is argued therefore that groups that use the internet for serious playthe use of avatars in virtual worlds is discussed as an examplepresent us with a form of online subjectivity that is rising in importance as a form of cultural agency inasmuch as the play component is premised upon the rejection of pre-packaged forms of agency. Support for a socially-just internet would thus mean supporting the online communities formed in this process. Thus the argument is put forward that the importance of serious online play groups is not due to their potential for forming communities per se but is rather due to their potential for resisting the imposition of agency. Inasmuch as online communities in the midst of such groups can bolster that goal, they can represent the development of human capabilities in a way that expands the theme of social justice.