Mass mortality of Strongylocentrotus droebachiensis (Echinodermata: Echinoidea) off Nova Scotia, Canada

1984 ◽  
Vol 78 (2) ◽  
pp. 153-164 ◽  
Author(s):  
R. E. Scheibling ◽  
R. L. Stephenson
Keyword(s):  
Nova Scotia ◽  
Mass Mortality ◽  
Strongylocentrotus Droebachiensis

Predation by Rock Crabs (Cancer irroratus) on Diseased Sea Urchins (Strongylocentrotus droebachiensis) in Nova Scotia

1984 ◽  
Vol 41 (12) ◽  
pp. 1847-1851 ◽  
Author(s):  
Robert E. Scheibling
Keyword(s):  
Nova Scotia ◽  
Sea Urchins ◽  
Mass Mortality ◽  
Strongylocentrotus Droebachiensis ◽  
Significant Preference ◽  
Laboratory Findings ◽  
Cancer Irroratus ◽  
Feeding Experiments ◽  
Defensive Behaviors ◽  
Strong Attachment

Predation of morbid sea urchins (Strongylocentrotus droebachiensis) by rock crabs (Cancer irroratus) and other predators was observed using SCUBA during an outbreak of disease in southwestern Nova Scotia in August 1983. Disease increases susceptibility of sea urchins to predation by precluding natural defensive behaviors including spine projection, strong attachment to the substratum, and aggregation. In laboratory feeding experiments, rock crabs preferred diseased or narcotized sea urchins over healthy ones and fed upon them at a much higher rate than crabs given only healthy sea urchins as prey. Rock crabs showed no significant preference between diseased and narcotized sea urchins. Rock crabs clearly preferred mussels over healthy or diseased sea urchins. Although rock crabs do not appear to be important predators of healthy sea urchins, from field and laboratory findings I conclude that they contribute to mass mortality of sea urchins by preying upon morbid individuals during outbreaks of disease.

scholarly journals Validating the identity of Paramoeba invadens, the causative agent of recurrent mass mortality of sea urchins in Nova Scotia, Canada

2013 ◽  
Vol 103 (3) ◽  
pp. 209-227 ◽  
Author(s):  
CJ Feehan ◽  
J Johnson-Mackinnon ◽  
RE Scheibling ◽  
JS Lauzon-Guay ◽  
AGB Simpson
Keyword(s):  
Nova Scotia ◽  
Causative Agent ◽  
Sea Urchins ◽  
Mass Mortality

Relationship Between Destructive Grazing by the Sea Urchin, Strongylocentrotus droebachiensis, and the Abundance of American Lobster, Homarus americanus, on the Atlantic Coast of Nova Scotia

1981 ◽  
Vol 38 (11) ◽  
pp. 1339-1349 ◽  
Author(s):  
W. G. Wharton ◽  
K. H. Mann
Keyword(s):  
Population Structure ◽  
Nova Scotia ◽  
Sea Urchins ◽  
Atlantic Coast ◽  
Homarus Americanus ◽  
Strongylocentrotus Droebachiensis ◽  
American Lobster ◽  
History Of ◽  
Kelp Bed ◽  
The Relationship

Relationships between percentage cover of macroalgae, population structure of sea urchins (Strongylocentrotus droebachiensis), and the history of the lobster fishery were examined at nine sites distributed along the Atlantic coast of Nova Scotia from Guysborough County in the northeast to Pubnico in the southwest. At Pubnico there was dense algal cover and a small number of urchins living in crevices, and at Cape Sable there was an area of transition, but at all other sites there were urchin-dominated barren grounds. When the population structure of the urchins was compared with that previously observed in St. Margaret's Bay before, during, and after destruction of beds of kelp (Laminaria spp. and Agarum) by overgrazing, it was concluded that kelp bed destruction occurred on the coast north of Halifax prior to 1970, and on the coast south of Halifax after 1970. From the records of American lobster (Homarus americanus) catches it was concluded that a critical decline in catches at each site occurred a few years after kelp bed destruction. Information from various sources is synthesized into a coherent theory of the relationship between lobsters, other predators, sea urchins, and kelp.Key words: lobsters, Homarus americanus; sea urchins, Strongylocentrotus droebachiensis; destructive grazing, kelp, Laminaria, Agarum

Amoebae in tissues of diseased echinoids (Strongylocentrotus droebachiensis) in Nova Scotia

Echinodermata ◽  
2020 ◽  
pp. 289-293
Author(s):  
G.M. Jones ◽  
R.E. Scheibling ◽  
A.J. Hebda ◽  
R.J. Miller
Keyword(s):  
Nova Scotia ◽  
Strongylocentrotus Droebachiensis

Erratum: Response of the sea urchin, Strongylocentrotus droebachiensis, to reduced salinities: importance of size, acclimation, and interpopulation differences

1984 ◽  
Vol 62 (11) ◽  
pp. 2352-2352 ◽  
Author(s):  
John H. Himmelman ◽  
Helga Guderley ◽  
Gilles Vignault ◽  
Guy Drouin ◽  
Peter G. Wells
Keyword(s):  
Nova Scotia ◽  
Strongylocentrotus Droebachiensis ◽  
Test Diameter ◽  
Lawrence Estuary ◽  
Stress Acclimation ◽  
Hypoosmotic Stress ◽  
Size Groups ◽  
Percentage Weight ◽  
St Lawrence Estuary ◽  
Neuromuscular Coordination

Weight change, mortality, and neuromuscular coordination, as measured by righting time, were used to evaluate the resistance of Strongylocentrotus droebachiensis to hypoosmotic stress. Acclimation to a salinity of 24 or 25‰ decreased the righting time of urchins after 96 h of hypoosmotic stress. The effect of acclimation was the same for four size groups of urchins (10–15, 20–25, 34–37, and 50–60 mm in test diameter). A comparison of urchins from the St. Lawrence Estuary and from Nova Scotia, both acclimated to 24‰, showed that for the three larger size classes, the salinity at which there was a significant increase in righting time was lower for urchins from an estuarine environment than for urchins from the oceanic environment. The percentage weight gain following hypoosmotic stress increased with decreasing urchin size. For small urchins the increase was less marked after acclimation to 24‰. The mortality rates following these experiments showed that acclimation to a reduced salinity increased the tolerance to hypoosmotic stress, that urchins from the St. Lawrence Estuary were better able to withstand low salinities than urchins from Nova Scotia, and that small urchins were more sensitive to osmotic stress than large urchins. The latter was confirmed in a field experiment in which four size groups of urchins were kept in cages at a location exposed to periodic decreases in surface salinities.

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