Over the last two decades, low-trophic-level fisheries have rapidly expanded in Atlantic Canada, largely compensating for collapsed groundfisheries; however, concerns have been raised regarding the limited background knowledge for many newly targeted species and their overexploitation in other regions. Using government stock assessments, we evaluated the amount of information available to assess population, fisheries, and ecosystem status in emerging (new since 1988), developing (expanding since 1988), and established fisheries on the Scotian Shelf. Emerging fisheries had significantly lower levels of population knowledge than developing and established fisheries. Importantly, knowledge was often lacking in basic population parameters such as growth rates, current biomass, and geographic range. In contrast, ecosystem knowledge, such as habitat disruption and recovery, was higher in emerging than established fisheries. Overall, quantitative knowledge was positively related to fishery value and greatest for 30- to 100-year-old fisheries. Although the number of government and general scientific publications greatly increased since 1990 for developing and established fisheries, publications for emerging fisheries remained at low levels. Emerging fisheries represent important socio-economic value in Atlantic Canada but may be progressing too rapidly for adequate knowledge to be gained, presenting a risk for their sustainable development.