Abstract Title

Session S-09E: Marine, Freshwater and Terrestrial Species: Threats and Conservation

Keywords

Species and Food Webs

Start Date

2-5-2014 10:30 AM

End Date

2-5-2014 12:00 PM

Description

The success of native oyster (Ostrea lurida) restoration efforts depends on the establishment of self-sustaining populations. However, as juveniles and spat, oysters are vulnerable to both native and invasive predators, and reduced survival at this stage could prevent oyster reestablishment. We investigated the separate and combined effects of native crabs and invasive oyster drills on the survival of juvenile Olympia oysters over four months at a restoration site in south Salish Sea (Liberty Bay, Puget Sound). As potential predators of both oysters and oyster drills, native crabs could generate complex tri-trophic dynamics, resulting in either net positive or negative effects on oyster populations. At our site, oyster drills were the strongest driver of oyster mortality, consuming up to 50% of juvenile oysters monthly. Predation rates by drills varied seasonally, peaking in July. Crabs had only a small positive indirect effect on oysters, transmitted by preying on drills rather than by reducing drill feeding rates. This experiment reinforces previous findings that invasive oyster drills can be a significant obstacle to restoration efforts, even in habitats where high densities of native crabs could mitigate the effects of drills on oysters.

Share

COinS
 
May 2nd, 10:30 AM May 2nd, 12:00 PM

Drill, baby, drill: Invasive oyster drills are the main driver of native oyster mortality at a restoration site

Room 613-614

The success of native oyster (Ostrea lurida) restoration efforts depends on the establishment of self-sustaining populations. However, as juveniles and spat, oysters are vulnerable to both native and invasive predators, and reduced survival at this stage could prevent oyster reestablishment. We investigated the separate and combined effects of native crabs and invasive oyster drills on the survival of juvenile Olympia oysters over four months at a restoration site in south Salish Sea (Liberty Bay, Puget Sound). As potential predators of both oysters and oyster drills, native crabs could generate complex tri-trophic dynamics, resulting in either net positive or negative effects on oyster populations. At our site, oyster drills were the strongest driver of oyster mortality, consuming up to 50% of juvenile oysters monthly. Predation rates by drills varied seasonally, peaking in July. Crabs had only a small positive indirect effect on oysters, transmitted by preying on drills rather than by reducing drill feeding rates. This experiment reinforces previous findings that invasive oyster drills can be a significant obstacle to restoration efforts, even in habitats where high densities of native crabs could mitigate the effects of drills on oysters.