Twenty-six years (1990–2015) of monitoring annual recruitment of the invasive zebra mussel (Dreissena polymorpha) in the Rideau River, a small river system in Eastern Ontario, Canada

We monitored the recruitment of young-of-year zebra mussels (Dreissena polymorpha (Pallas, 1771)) each autumn at 13 locations within four river reaches along the length (100 km) of the Rideau River, starting in 1990, the year of its discovery in that river, until 2015. Sampling was conducted on bottom structures of locks or on seasonally exposed substrate during autumn drawdowns conducted by Rideau Canal staff. Twenty-six years of monitoring zebra mussels in that river revealed a distinct and persistent upstream–downstream pattern, with highest densities occurring in the two downstream reaches. A “lake effect” was observed at Long Reach, where veligers have ideal conditions for larval development. Highest densities occurred in the mid-1990s, comparable with those reported in the Laurentian Great Lakes during peak invasion (200 000 to 500 000+ mussels/m2). Although the most upstream reaches of the river had low recruitment rates and low densities initially (0.01 to 10 mussels/m2), annual recruitment progressively increased to higher values (10 to 1000+ mussels/m2) because more veligers from the Rideau Lakes and the river headwaters were produced and drifted into the system. This study is unique because it provides a thorough understanding of the 26 years of invasion history of the zebra mussel in a small river system.

Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists

<em>Abstract</em>.—Muskies Canada Inc. (MCI) has represented Muskellunge <em>Esox masquinongy </em>anglers since 1978, advocating for the conservation and effective management of Muskellunge populations. A core initiative of MCI, since its inception, has been the voluntary Angler Log Program (ALP), which collects data on MCI-member Muskellunge angling effort and catch. These data are shared with the Ontario Ministry of Natural Resources and Forestry with the intent of contributing to the management of Muskellunge fisheries in Ontario. This paper examines the data provided by MCI members of the six water bodies with the highest representation in the ALP from 1995 to 2015—Pigeon Lake, Rideau River, Lake St. Clair, Georgian Bay, St. Lawrence River, and Ottawa River. Mean length, catch per unit effort, and proportional size are examined to determine (1) if a response to large-scale changes in fish abundance (viral hemorrhagic septicemia-related die-offs) can be detected in the data, and (2) if data from the ALP relate to the broad management objectives for the fishery. While the ALP is subject to some sources of bias, our assessment suggests that there is considerable potential for direct use of the data in setting and measuring fishery, and Muskellunge population, objectives.

Nitrification kinetics and modified model for the Rideau River, Canada

Improving kinetic modeling of nitrification in rivers is of growing importance due to yearly increases in the anthropogenic release of nitrogen into rivers around the world. The use of water quality models can abate the expense of water quality monitoring while enabling the user to predict trends of variation. Data collected from a series of laboratory kinetic experiments were used to calculate the rate of nitrification in the Rideau River, Canada, and modify nitrification algorithms used in the traditional water quality model Qual2E. The modified model relates the reaction rate coefficients with a simple biomass concentration measurement of volatile suspended solids (VSS) in the river and subsequently introduces biomass growth functions directly into the kinetic algorithm. Furthermore, this modified model includes a nitrate-nitrogen assimilation pathway. The modified model demonstrates an improved correlation to nitrogen parameters observed in river water samples compared with the classical water quality model Qual2E. The inclusion of bacterial concentrations based upon the simple measurement of VSS plays a critical role in the reactions of the nitrification system and nitrate-nitrogen assimilation is an important pathway at low ammonia-nitrogen concentrations.

Rumo a uma abordagem integrada da conservação e uso sustentável da biodiversidade: lições aprendidas a partir do projeto da biodiversidade do Rio Rideau

Na busca de estratégias para a conservação dos recursos biológicos globais, vem sendo reconhecido, com intensidade crescente, que os métodos científicos convencionais e os arranjos institucionais nem sempre são eficientes para se lidar com a complexidade embutida nas dimensões biofísicas e sociopolíticas desta problemática. No enfrentamento desses desafios, torna-se necessária uma abordagem integrada, capaz de combinar métodos científicos com valores societários. As pesquisas participativas promovem mudanças sociais ao capacitarem as comunidades a encontrar opções adequadas - do ponto de vista coletivo e cultural - para a concretização do desenvolvimento sustentável nos seus próprios termos. A gestão ecossistêmica reconhece a interconectividade dos sistemas sociais e ecológicos e tenta articular a pesquisa científica, a formulação de políticas públicas e o estabelecimento de objetivos societários por meio de pesquisas interdisciplinares e processos de tomada de decisões envolvendo múltiplos atores sociais. Em 1998, o Canadian Museum of Nature (CMN), sediado em Ottawa, em parceria com agências governamentais, instituições educacionais e grupos comunitários iniciaram um estudo multidisciplinar de três anos sobre a saúde do ecossistema do Rio Rideau, na região oriental de Ontário. Este artigo apresenta o Projeto de Conservação da Biodiversidade do Rio Rideau - PBRR (Rideau River Biodiversity Project - RRBP) como um estudo de caso baseado na aplicação de uma abordagem integrada para avaliar a biodiversidade de um ecossistema de água doce. Na parte final, apresentamos uma estrutura conceitual para a construção de uma abordagem integrada da conservação e do uso sustentável da biodiversidade, capaz de combinar os pontos fortes da pesquisa participativa no nível comunitário e da gestão ecossistêmica, mediante um processo de aprendizagem social e investigação transdisciplinar.