Modeling the spatial and temporal resource use by shortnose sturgeon (Acipenser brevirostrum) throughout the species' life history
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Date
2012
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University of New Brunswick
Abstract
The shortnose sturgeon is a North American species, found along the Atlantic coast of the US and Canada. Like the other 24 species of sturgeon found around the world, shortnose sturgeon, though once abundant, are now decimated throughout most of the species' range. The Saint John River offers a unique opportunity to conduct research on shortnose sturgeon, as the population it harbours is the second largest throughout the species' range. This study, conducted between 2008 and 2012, addresses some of the knowledge gaps in the ecology of shortnose sturgeon, focusing on 1) growth and behaviour of early life stages, 2) foraging ecology in adults, and 3) overwintering habitat use of adults. Early life stages have been identified as the bottleneck of recruitment for many sturgeon species. The combination of field collections with modeling allowed me to 1) determine the timing of successful spawning, hatching and larval migration, 2) calculate estimates of larval abundance, and 3) model larval drift vs. environmental parameters, identifying water temperature, night-time dam discharge and transect location as environmental parameters that influence larval dispersal. For the adult stage research, I 1) examined the relationship between foraging habits and location, salinity, season and sturgeon length, 2) provided the first account of digestion efficiency in fresh and brackish environments, 3) estimated the year-to-year variability in numbers of overwintering fish, and 4) characterized the age distribution of sturgeon aggregated for overwintering. These studies allowed me to describe the behaviour of shortnose sturgeon during foraging (summer to late fall), overwintering (late fall to early spring) and reproductive seasons. The similarity in reproductive and foraging behaviours across most sturgeon species allow application of my results to other species of sturgeon, as well as other populations of shortnose sturgeon. This work will enable us to provide critical information for conservation and management efforts of the shortnose sturgeon in the Saint John River, NB, Canada.