Monitoring Eelgrass in Gulf Islands National Park Reserve

In what habitat can you find over 90 different species of fish in British Columbia? Eelgrass meadows provide important complex structure and nursery function for young fish to grow and thrive. Since 2004, Parks Canada has monitored eelgrass fish assemblages annually in Pacific Canada’s National Parks and has developed a framework to assess their status and trend overtime. Gulf Islands National Park Reserve (GINPR) is one of three National Park Reserves, in which this monitoring framework has been implemented. The eelgrass meadows in the GINPR region of the Salish Sea are under constant threat from development, pollution and recreational activities such as anchoring. This presentation will talk about the framework through which we monitor eelgrass meadows at 12 sites in the Southern Gulf Islands in terms of the methods used and how we analyze the data to reach conclusions about the condition of meadows in our area of the Salish Sea. The talk will present some of our findings to give the audience a sense of the trends we see in fish assemblages and eelgrass plant health in Gulf Islands National Park Reserve

Experimentally Determining Optimal Conditions for Mapping Forage Fish with RPAS

RPAS (Remotely piloted aircraft systems, i.e., drones) present an efficient method for mapping schooling coastal forage fish species that have limited distribution and abundance data. However, RPAS imagery acquisition in marine environments is highly dependent on suitable environmental conditions. Additionally, the size, color and depth of forage fish schools will impact their detectability in RPAS imagery. In this study, we identified optimal and suboptimal coastal environmental conditions through a controlled experiment using a model fish school containing four forage fish-like fishing lures. The school was placed at 0.5 m, 1.0 m, 1.5 m, and 2.0 m depths in a wide range of coastal conditions and then we captured RPAS video imagery. The results from a cluster analysis, principal components, and correlation analysis of RPAS data found that the optimal conditions consisted of moderate sun altitudes (20–40°), glassy seas, low winds (<5 km/h), clear skies (<10% cloud cover), and low turbidity. The environmental conditions identified in this study will provide researchers using RPAS with the best criteria for detecting coastal forage fish schools

The Green Wave: Reviewing the Environmental Impacts of the Invasive European Green Crab (Carcinus maenas) and Potential Management Approaches

The European green crab (Carcinus maenas), native to northwestern Europe and Africa, is among the top 100 most damaging invasive species globally. In some regions, including the Atlantic coast of North America, C. maenas has caused long-term degradation of eelgrass habitats and bivalve, crab, and finfish populations, while areas are near the beginning of the invasion cycle. Due to high persistence and reproductive potential of C. maenas populations, most local and regional mitigation efforts no longer strive for extirpation and instead focus on population control. Long-term monitoring and rapid response protocols can facilitate early detection of introductions that is critical to inform management decisions related to green crab control or extirpation. Once C. maenas are detected, local area managers will need to decide on management actions, including whether and what green crab control measures will be implemented, if local invasion might be prevented or extirpated, and if population reduction to achieve functional eradication is achievable. Due to the immense operational demands likely required to extirpate C. maenas populations, combined with limited resources for monitoring and removal, it is unlikely that any single government, conservation and/or academic organization would be positioned to adequately control or extirpate populations in local areas, highlighting the importance of collaborative efforts. Community-based monitoring, and emerging methods such as environmental DNA (eDNA), may help expand the spatial and temporal extent of monitoring, facilitating early detection and removal of C. maenas. While several C. maenas removal programs have succeeded in reducing their populations, to our knowledge, no program has yet successfully extirpated the invader; and the cost of any such program would likely be immense and unsustainable over the long-term. An alternative approach is functional eradication, whereby C. maenas populations are reduced below threshold levels such that ecosystem impacts are minimized. Less funding and effort would likely be required to achieve and maintain functional eradication compared to extirpation. In either case, continual control efforts will be required as C. maenas populations can quickly increase from low densities and larval re-introductions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author