Disease as a control of sea urchin populations in Nova Scotian kelp beds

2014 ◽  
Vol 500 ◽  
pp. 149-158 ◽  
Author(s):  
CJ Feehan ◽  
RE Scheibling
Keyword(s):  
Sea Urchin ◽  
Kelp Beds ◽  
Nova Scotian

Destructive Grazing of Kelp by Sea Urchins in Eastern Canada

1976 ◽  
Vol 33 (6) ◽  
pp. 1278-1283 ◽  
Author(s):  
P. A. Breen ◽  
K. H. Mann
Keyword(s):  
Nova Scotia ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Large Contribution ◽  
Eastern Canada ◽  
Kelp Beds ◽  
Urchin Grazing

Destruction of kelp beds by sea urchins has been documented in St. Margaret’s Bay, Nova Scotia, and also appears to be taking place in other parts of eastern Canada. Continued sea urchin settlement onto grazed areas prevents the return of kelp and other algae for long periods. Because of the large contribution of kelp beds to coastal productivity, the disappearance of kelp from large areas is alarming. Dynamics of sea urchin grazing are discussed.

Changes in sea urchin populations after the destruction of kelp beds

1976 ◽  
Vol 36 (4) ◽  
pp. 321-326 ◽  
Author(s):  
C. Lang ◽  
K. H. Mann
Keyword(s):  
Sea Urchin ◽  
Kelp Beds

The Relation Between Lobster Abundance, Sea Urchins, and Kelp Beds

1972 ◽  
Vol 29 (5) ◽  
pp. 603-605 ◽  
Author(s):  
K. H. Mann ◽  
P. A. Breen
Keyword(s):  
Sea Urchin ◽  
Food Supply ◽  
Sea Urchins ◽  
Critical Density ◽  
Eastern Canada ◽  
Kelp Beds ◽  
Key Species

When subtidal communities are disturbed and sea urchin populations expand, they frequently overgraze their food supply, eliminating large seaweeds from considerable areas. The hypothesis is advanced that the lobster is a key species, controlling sea urchin populations in eastern Canada, and that reduction of lobster populations below a critical density has led to overgrazing of seaweeds in many places.

Diversity, Patterns of Adaptation, and Stability of Nova Scotian Kelp Beds

1988 ◽  
Vol 58 (2) ◽  
pp. 129-154 ◽  
Author(s):  
Craig R. Johnson ◽  
Kenneth H. Mann
Keyword(s):  
Diversity Patterns ◽  
Kelp Beds ◽  
Nova Scotian

Diversity, Patterns of Adaptation, and Stability of Nova Scotian Kelp Beds

1988 ◽  
Vol 58 (3) ◽  
pp. 227-227 ◽  
Author(s):  
Craig R. Johnson ◽  
Kenneth R. Mann
Keyword(s):  
Diversity Patterns ◽  
Kelp Beds ◽  
Nova Scotian

Destructive grazing, epiphytism, and disease: the dynamics of sea urchin - kelp interactions in Nova Scotia

1999 ◽  
Vol 56 (12) ◽  
pp. 2300-2314 ◽  
Author(s):  
Robert E Scheibling ◽  
Allan W Hennigar ◽  
Toby Balch
Keyword(s):  
Nova Scotia ◽  
Sea Urchin ◽  
Canopy Cover ◽  
Strongylocentrotus Droebachiensis ◽  
Exposed Site ◽  
Membranipora Membranacea ◽  
Kelp Beds ◽  
Sheltered Site ◽  
Kelp Canopy ◽  
Over Time

We measured the rate of advance of urchin (Strongylocentrotus droebachiensis) feeding aggregations (fronts) as they destructively grazed kelp beds (Laminaria longicruris) at both a wave-exposed site and a sheltered site in Nova Scotia over 3.5 years. The grazing fronts were composed of high densities of large adults (up to 98 and 70 per 0.25 m2 at the exposed and sheltered sites, respectively). Urchins in the recently formed barrens, or in adjacent kelp beds, occurred at much lower densities and consisted mainly of juveniles. The fronts moved onshore into shallower water at each site, but their rate of advance varied markedly between sites and over time at each site, ranging from 0 to 4 m·month-1. The rate of advance of a front was related to the biomass of urchins; fronts did not advance below a threshold biomass of ~2 kg·m-2. Infestations of kelp by an epiphytic bryozoan (Membranipora membranacea) caused marked reductions in kelp canopy cover and biomass during winter, but the canopy regenerated through recruitment of juvenile sporophytes in spring. A localized outbreak of disease decimated S. droebachiensis at the exposed site in 1993, which enabled kelp to recolonize the barrens. Surviving urchins gradually reaggregated and resumed destructive grazing after ~1.5 years. A recurrence of disease in 1995 eliminated urchins at both sites and terminated the transition from kelp beds to barrens on a coastal scale. Our findings have important implications for the management of the urchin fishery, which targets grazing fronts for harvesting.

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