One of the responsible ways Trans Mountain minimizes environmental impacts of marine construction is by ceasing in-water construction activities if any marine mammal is observed adjacent to or within the project area. Recently, Trans Mountain suspended impact pile driving at Westridge Marine Terminal while a Burrard Inlet research group escorted a stray sea lion back to its home base.

The Stellar sea lion’s home is the Open Water Research Station (OWRS), located east of Westridge in the Port Moody Arm of Burrard Inlet. Four Stellars, all female, reside there. They’re part of a research project, led by the Vancouver Aquarium and the University of British Columbia, which studies sea lions and seals.

The Stellars have habitats at the station and are allowed daily to free swim and dive. On July 9, 2018, however, one of the quartet undertook a longer than expected swim and didn’t return. OWRS contacted Trans Mountain’s environmental inspector at Westridge and requested that construction personnel be on the lookout for the sea lion.

No sightings were reported by Trans Mountain Expansion Project or contractor staff through the end of the work day. Trans Mountain’s environmental inspector committed to maintaining the lookout the next day and to immediately reporting any sightings.

The next day an OWRS team aboard the station’s research vessel sighted the wandering sea lion in False Creek near Science World and began the process of escorting the well-trained creature home.

“The sea lion was guided back to the research station by OWRS representatives,” Trans Mountain reported in its most recent monthly report to the department of Fisheries and Oceans Canada (DFO). The report also noted that Trans Mountain’s environmental inspector “maintained close communication with the OWRS representative to ensure that impact driving was suspended until the sea lion had passed through the exclusion zone.”

The sea lion swim-past was one of several occasions in July when marine mammal sightings led to stops and postponements of impact pile driving at Westridge, according to the report. On numerous other occasions, harbor seal sightings stopped the work.

Impact pile driving is delayed or stopped when marine mammals are in the Project’s exclusion zone. For cetaceans and endangered marine mammal species, the respective exclusion zone encompasses a 1.74-kilometre radius of the worksite. For seals the exclusion zone is 150 metres.

Beginning 30 minutes before the start of in-water activity such as impact pile driving, qualified personnel continuously scan the inner and outer exclusion zones. Work cannot commence unless the respective zones are clear. If an animal enters a zone when work is underway, the work must stop and cannot resume until the zone has been clear for 30 minutes. More information about managing impacts of underwater noise is available in the Westridge Environmental Protection plan – filed in compliance with NEB Condition 81 (Filing ID A909073).