scholarly journals Population dynamics of an ecologically important range-extender: kelp beds versus sea urchin barrens

2009 ◽  
Vol 374 ◽  
pp. 113-125 ◽  
Author(s):  
SD Ling ◽  
CR Johnson
Keyword(s):  
Population Dynamics ◽  
Sea Urchin ◽  
Kelp Beds ◽  
Range Extender ◽  
Sea Urchin Barrens

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.

scholarly journals The challenge of managing the commercial harvesting of the sea urchin Paracentrotus lividus: advanced approaches are required

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10093
Author(s):  
Simone Farina ◽  
Maura Baroli ◽  
Roberto Brundu ◽  
Alessandro Conforti ◽  
Andrea Cucco ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Current Speed ◽  
Predatory Fish ◽  
Bottom Current ◽  
Environmental Constraints ◽  
Calcareous Rock ◽  
Commercial Size

Sea urchins act as a keystone herbivore in marine coastal ecosystems, regulating macrophyte density, which offers refuge for multiple species. In the Mediterranean Sea, both the sea urchin Paracentrotus lividus and fish preying on it are highly valuable target species for artisanal fisheries. As a consequence of the interactions between fish, sea urchins and macrophyte, fishing leads to trophic disorders with detrimental consequences for biodiversity and fisheries. In Sardinia (Western Mediterranean Sea), regulations for sea urchin harvesting have been in place since the mid 90s. However, given the important ecological role of P. lividus, the single-species fishery management may fail to take into account important ecosystem interactions. Hence, a deeper understanding of population dynamics, their dependance on environmental constraints and multispecies interactions may help to achieve long-term sustainable use of this resource. This work aims to highlight how sea urchin population structure varies spatially in relation to local environmental constraints and species interactions, with implications for their management. The study area (Sinis Peninsula, West Sardinia, Italy) that includes a Marine Reserve was divided into five sectors. These display combinations of the environmental constraints influencing sea urchin population dynamics, namely type of habitat (calcareous rock, granite, basalt, patchy and continuous meadows of Posidonia oceanica), average bottom current speed and predatory fish abundance. Size-frequency distribution of sea urchins under commercial size (<5 cm diameter size) assessed during the period from 2004 to 2007, before the population collapse in 2010, were compared for sectors and types of habitat. Specific correlations between recruits (0–1 cm diameter size) and bottom current speeds and between middle-sized sea urchins (2–5 cm diameter size) and predatory fish abundance were assessed. Parameters representing habitat spatial configuration (patch density, perimeter-to-area ratio, mean patch size, largest patch index, interspersion/juxtaposition index) were calculated and their influence on sea urchin density assessed. The density of sea urchins under commercial size was significantly higher in calcareous rock and was positively and significantly influenced by the density and average size of the rocky habitat patches. Recruits were significantly abundant in rocky habitats, while they were almost absent in P. oceanica meadows. The density of middle-sized sea urchins was more abundant in calcareous rock than in basalt, granite or P. oceanica. High densities of recruits resulted significantly correlated to low values of average bottom current speed, while a negative trend between the abundance of middle-sized sea urchins and predatory fish was found. Our results point out the need to account for the environmental constraints influencing local sea urchin density in fisheries management.

Effects of the parasitic nematode Echinomermella matsi on growth and survival of its host, the sea urchin Strongylocentrotus droebachiensis

1999 ◽  
Vol 77 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Audun Stien
Keyword(s):  
Population Dynamics ◽  
Sea Urchin ◽  
Parasitic Nematode ◽  
Sea Urchins ◽  
Strongylocentrotus Droebachiensis ◽  
Probability Models ◽  
Negative Effects ◽  
Growth And Survival ◽  
Host Growth ◽  
Reproductive Rates

It has been suggested that the parasitic nematode Echinomermella matsi significantly affects the population dynamics of its host, the sea urchin Strongylocentrotus droebachiensis. The effects of infection on both host fecundity and host survival may be of importance. The fecundity of sea urchins is related to their size. Negative effects of infection on host growth will therefore reduce reproductive rates. I estimated the effect of infection on host growth and survival in two naturally infected wild sea urchin populations using a capture-mark-recapture approach. Infected and uninfected sea urchins were captured and marked with unique tags or recaptured seven times from June 1994 to September 1996. The increment in the diameter of marked sea urchins between captures was used to measure sea urchin growth. The effect of E. matsi infection on host growth was small. Mortality rates were estimated using survival probability models based on the methodology developed by Cormack, Jolly, and Seber. The effect of infection on host survival was pronounced, with estimated sea urchin life expectancies reduced by 33-86% by E. matsi infection. This suggests that E. matsi may affect the population dynamics of S. droebachiensis significantly through the effect on host survival.

Effect of a cold event on population and community of pit-inhabiting sea urchins in Western Pacific coasts

2021 ◽  
Vol 101 (5) ◽  
pp. 819-826
Author(s):  
Luna Yamamori ◽  
Makoto Kato
Keyword(s):  
Sea Urchin ◽  
Community Dynamics ◽  
Sea Urchins ◽  
Tropical Species ◽  
Subtidal Zone ◽  
Snail Species ◽  
Slow Recovery ◽  
Cold Event ◽  
Population And Community Dynamics ◽  
Sea Urchin Barrens

AbstractCoastal tide pools in southern Japan are inhabited by the rock-boring sea urchin Echinostrephus molaris, which excavate pits in the substrate. These pits are subsequently used by non-boring sea urchins such as Anthocidaris crassispina and Echinometra sp. B, and the recolonized pits are often inhabited by a commensal limpet-like trochid snail species, Broderipia iridescens. We explored the population and community dynamics of these sea urchins and the limpet-like snail by monitoring occupancy of 512 pits in tide pools in Shirahama, Japan from May 2017–May 2019. Initially, nearly all pits were occupied by any one of the three sea urchin species, but an unusual cold event in February 2018 caused a mass die off of these sea urchins. After this event, occupancy decreased from 99% to 15%, and the tropical species Echinometra sp. B disappeared from the study pools. We observed slow population recovery of E. molaris and A. crassispina, provably via migration of sub-adults from the subtidal zone. Turnover rate of the pit-occupying sea urchin species was <1.0% before the cold event, but drastically increased after the cold event. Population size of the commensal snail decreased along with those of their host, but the rate of commensalism was constant at 50–55% throughout the study period, suggesting that these snails followed their host sea urchins repeating inter-pit migration. Despite mass mortality and slow recovery, the sea urchin density remained high enough to maintain persistent sea urchin barrens throughout the study period.

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
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