Stares, J. C., Rideout, R. M., Morgan, M. J., and Brattey, J. 2007. Did population collapse influence individual fecundity of Northwest Atlantic cod? – ICES Journal of Marine Science, 64:1338 –1347. We examined the influence of population collapse on individual potential fecundity and total population egg production (TEP) of three northwest Atlantic cod (Gadus morhua) populations: northern cod (Divisions 2J3KL), southern Grand Bank cod (NAFO Divisions 3NO), and southern Newfoundland cod (Subdivision 3Ps). Fecundity at length increased in conjunction with population collapse for two (3NO, 3Ps) of the three populations. Subsequent moderate population recovery between the 1990s and 2000s in 3Ps was accompanied by a decrease in fecundity at length. A large decrease in fecundity at length for 3NO during the same time period, despite little or no population recovery, coupled with the fact that there was no obvious difference in fish condition between the two time periods, suggested that density-independent factors could be contributing to the changes in fecundity. Use of pre-collapse fecundity–length relationships to estimate TEP in the post-collapse period resulted in underestimation of TEP by as much as 30% in 3NO and 46% in 3Ps, whereas in 2J3KL, TEP was overestimated by as much as 18%. Although the results do not fully support the hypothesis of an inverse relationship between population size and fecundity, they do demonstrate the variable nature of cod fecundity which, if not accounted for, can lead to erroneous perceptions of stock reproductive potential.

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ObjectivesUnderlying the delivery of services by the universal Canadian health care system are a number of rich secondary administrative health data sets which contain information on persons who are registered for care and details on their contacts with the system. These datasets are powerful sources of information for investigation of non-notifiable diseases and as an adjunct to traditional communicable disease surveillance. However, there are gaps between public health practitioners, access to these data, and access to experts in the use of these secondary data. The data linkage requires in-depth knowledge of these data including usages, limitations and data quality issues and also the skills to extract data to support secondary usage. OLAP reports have been developed to support operation needs but not on advanced analytics reports for surveillance and cohort study. To fill these gaps, we developed a set of web-based modular, parameterized, extraction and reporting tools for the purpose of: 1) decreasing the time and resources necessary to fill general secondary data requests for public health audiences; 2) quickly providing information from descriptive analysis of secondary data to public health practitioners; 3) informing the development of data feeds for continued enhanced surveillance or further data access requests; 4) assisting in preliminary stages of epidemiological investigations of non-notifiable diseases; and, 5) facilitating access to information from secondary data for evidence-based decision making in public health. ApproachWe intend to present these tools by case study of their application to small area analysis of secondary data in the context of air quality concerns. Data sources include individuals registered for health care coverage in BC, hospital separations, physician consultations, chronic disease registries, and drugs dispensation. Data sets contain complete information from 1992. Data were extracted and analyzed to describe the occurrence of health service utilization for cardiovascular and respiratory morbidity. Analysis was undertaken for BC residents in areas identified by local public health as priorities for monitoring. Health outcomes were directly standardized by age and compared to provincial trends by use of the comparative morbidity figure. ResultsResults will include descriptive epidemiological analysis of secondary data relating to respiratory and cardiovascular morbidity in the context of air quality concerns, summary of next steps, as well as an assessment of tool performance. ConclusionsWhere adopted tools such as these can make information from secondary data more accessible to support public health practice, particularly in regions with low analytical or epidemiological capacity.