One of the themes I have found emerging from my project of blogging about species extinct in Ireland since human habitation is how hidden much of this biodiversity loss is. moths, mosses and flowers go extinct quietly. People may occasionally notice the absence of birdsong, or a lack of wildflowers, or the dominance of an invasive species, but all too much extinction is under the radar.
This is even more stark for marine ecosystems. In Whittled Away, Pádraic Fogarty has a whole chapter on marine life, and the successive pattern of overfishing and decline. As posted before, determining precisely if a marine species is totally extinct is difficult. Yet we can be sure of dramatic, if not terminal declines.
One example is the purple sea urchin. Fogarty writes:
Purple sea urchin
What it is : Spiny echinoderm once widespread and common on rocky shores
350 t landed in 1976
48t landed in 1986
6t landed in 1997
Not listed after 2003
Before exploitation it was estimated that one inlet in Galway Bay had 1,600 individuals per m2. Today they are very hard to find.
From the Friends of the Irish Environment web page:
Purple Sea Urchin: This species was over fished and is now locally extinct. Landings were as high as 375 tonnes in 1976 and are now down to zero. This is a key species therefore its local extinction will have an impact on the associated marine community
The Irish Wildlife Trust’s Protecting Our Ocean’s Wealth report states that the most recent records of this species date from the mid 1990s.