Research Document - 2014/003

Documentation of Maritime Traffic and Navigational Interactions with St. Lawrence Estuary Beluga (Delphinaterus leucas) in Calving Areas Between 2003 and 2012

By Nadia Ménard, Robert Michaud, Clément Chion and Samuel Turgeon

Abstract

Anthropogenic disturbance resulting from navigation is considered a current threat to the recovery of the St. Lawrence Estuary (SLE) beluga population, in addition to contaminants, changes in abundance and type of prey as well as habitat degradation (DFO 2012). Many hypotheses, including anthropogenic disturbance, were proposed in attempts to explain the increase in number of calf carcasses found in 2010 and 2012, as well as in female mortalities due to dystocia (Lair et al. 2014). The principal concern regarding maritime activities for the beluga population stems from the fact that these activities peak in July and August during the period of beluga calving and caring for newborns. Furthermore, areas of high residency of belugas are easily accessible by boats of all types in this coastal region. Various data bases and information were brought together to document maritime traffic and navigational interactions with beluga from 2003 to 2012. Although the information collected was not specifically designed to address whether anthropogenic disturbance from navigation could be a risk factor for calving females and newborn calves, we documented an increase in some types of navigational activities in specific portions of the critical habitat of the population over the past decade. The high number of calf mortalities reported in 2010 and 2012 coincide with peaks in recreational boating activity in Tadoussac marina, higher co-occurrences between belugas and boats in the Saguenay Fjord, and good weather conditions in the critical habitat during July and August. These results suggest that anthropogenic disturbance may have played a role in the increase in mortalities reported for those years. These results indicate a need to address anthropogenic disturbance in a strategic manner by focusing on specific areas at critical times for calving females and newborn.

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