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Synchronized hatch and its ecological significance in rainbow smelt Osmerus mordax in St. Mary's Bay, Newfoundland

dc.contributor.authorBradbury, IRen_US
dc.contributor.authorCampana, SEen_US
dc.contributor.authorBentzen, Paulen_US
dc.contributor.authorSnelgrove, PVRen_US
dc.date.accessioned2013-07-04T14:53:47Z
dc.date.available2013-07-04T14:53:47Z
dc.date.issued2004-11en_US
dc.description.abstractEarly life history stages in most marine animals are subject to high mortality through predation, starvation, and dispersal. Accordingly, the potential exists for the selection of behavioral mechanisms that reduce mortality. We examined the ecological significance of synchronization in hatch and the initiation of larval drift in rainbow smelt, Osmerus mordax, populations in St. Mary's Bay, Newfoundland. Larval abundances from six 24-h ring net surveys (2-h intervals) in Colinet and Salmonier Rivers during 2002/2003 suggest synchronized hatch following dusk (similar to2200 h). Monitoring of egg hatching in situ confirmed synchrony was at hatch and not emergence. Larval abundance showed no relationship with temperature or flow rates, and the consistency in hatch pattern suggested a light/dark cue. In experimental manipulations in which eggs were exposed to light and dark conditions for 2-h periods, hatch percentages were up to five times higher (p < 0.005) in dark treatments. We hypothesized that the linkage of hatch to low light levels represents a mechanism to avoid elevated larval predation in daylight conditions. Egg predation determined from predator gut content analysis suggested that extreme predation risk from small (< 20 cm) salmonids peaked during the day, prior to dusk, and was lowest during night (2200-0400 h). Microcosm experiments demonstrated that newly hatched larvae exposed to predators in dark conditions did not change in number, but mortality averaged 60% in light conditions. Our results suggest that predation pressure during the early life history of aquatic organisms might play a strong role in the optimization of aquatic life histories.en_US
dc.identifier.citationBradbury, IR, SE Campana, P. Bentzen, and PVR Snelgrove. 2004. "Synchronized hatch and its ecological significance in rainbow smelt Osmerus mordax in St. Mary's Bay, Newfoundland." Limnology and Oceanography 49(6): 2310-2315. DOI:10.4319/lo.2004.49.6.2310en_US
dc.identifier.issn0024-3590en_US
dc.identifier.issue6en_US
dc.identifier.startpage2310en_US
dc.identifier.urihttp://hdl.handle.net/10222/28644
dc.identifier.urihttp://dx.doi.org/10.4319/lo.2004.49.6.2310
dc.identifier.volume49en_US
dc.relation.ispartofLimnology and Oceanographyen_US
dc.titleSynchronized hatch and its ecological significance in rainbow smelt Osmerus mordax in St. Mary's Bay, Newfoundlanden_US
dc.typearticleen_US

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