Other Potential Agents of Change
Physical disturbance by storms
It is conceivable that severe storms could break up and scatter
individual brittlestar beds. However, the decadal persistence of beds in areas such as the
western Channel shows that at this geographic scale, populations can withstand the annual
extremes of weather.
Pathogens or parasites
Dense aggregations of brittlestars would seem to offer ideal conditions
for the rapid spread of pathogenic organisms or parasites, but so far no examples of this
have been recorded. However, several examples are known of echinoderm populations that
have been massively reduced by sudden oubreaks of epidemic disease. Cases include the mass
mortality of the sea urchin Diadema antillarum throughout the Caribbean as a result
of infection by a water-borne pathogen (Lessios, 1988), and the decimation of urchin
populations in the North Atlantic by parasitic amoebae and nematodes (Hagen, 1995).
Epidemic disease should therefore be considered as having the potential to significantly
affect populations of bed-forming brittlestars.