Using GIS based multi-criteria evaluation (MCE) and least cost pathway models to identify low-impact routes for commercial shipping and marine tourism
Seaborne transportation of goods currently makes up 90% of global trade. Vessel density has significantly increased within inner route channel navigation, making shipping activity a leading concern for marine mammal conservation, species vulnerability, and potential declining populations. Cetaceans (whales, dolphin, and porpoise species) are species of primary concern in these inner channel areas and are focused on within this study. This study has two different components, first to create alternative commercial shipping routes that reduce cetacean-vessel interaction in the Vancouver Island area. The second component is to identify areas within the same region that have increased sighting opportunities for marine tourism and research vessels. Multi-criteria evaluation (MCE) model and least cost pathway analysis were developed for both components to form the new routes. Both of the models combine local cetacean sightings data, shipping density data, and environmental constraints and factors such as water depth, protected areas, and threatened species. The output layers and values are then used with the cost pathway tool in ArcGIS to develop new shipping routes that will lower potential risks and impacts on cetaceans by avoiding the identified high-risk areas. Newly calculated weightings unique to each criterion are then applied to create the most ideal routes for other activities such as marine tourism and research to increase the likelihood of sightings and accuracy of predicting species location. The overall goal of this model is to lower human interaction with vulnerable species and populations and to lower the amount of interference caused by large shipping such as ship strikes, noise pollution and habitat disruption. Three alternative shipping routes were calculate, each route reduced the risk of vessel cetacean impact compared to current commercial routes. Route 1, Victoria to Vancouver was the most successful, reducing the most moderate to high risk cells and also was a feasible length for shipping companies. Four marine tourism routes were developed, travelling towards identified high density cetacean sightings area. This study successful identified alternative routes for commercial shipping and proposed new feasible routes for marine tourism and research vessels.