Thursday, April 5, 2012

New study on the worlds dwindling oyster beds.


Originally posted 2/3/2011 - I missed a story in November Im adding and reposting now:



21 Nov 2011: Report

Northwest Oyster Die-offs Show Ocean Acidification Has Arrived 


For the past six years, wild oysters in Willapa Bay, Washington, have failed to reproduce successfully because corrosive waters have prevented oyster larvae from forming shells. Wild oysters in Puget Sound and off the east coast of Vancouver Island also have experienced reproductive failure because of acidic waters. Other wild oyster beds in the Pacific Northwest have sustained losses in recent years at the same time that scientists have been measuring alarmingly corrosive water along the Pacific coast.

The situation at the hatcheries has improved substantially in the past couple of years, thanks largely to an ongoing, intensive scientific monitoring effort and to measures to control the pH of seawater in the tanks where oyster larvae are raised. But ocean acidification continues apace, which makes understanding what’s been happening to Whiskey Creek oysters vital to grasping what will eventually threaten every ocean organism that builds a shell or coral branch.

 
This time lag is important because oceans absorb about 50 percent of the CO2 released by burning fossil fuels, emissions that have been rising dramatically in recent decades. According to the National Oceanic and Atmospheric Administration (NOAA) ocean acidity has increased approximately 30 percent since the Industrial Revolution, and if we continue our current rate of carbon emissions, global oceans could be 150 percent more acidic by the end of the century than they have been for 20 million years.






Original post:


Oyster Reefs at Risk andRecommendations for Conservation,Restoration, and Management


We examined the condition of oyster reefs across 144 bays and 44 ecoregions; our comparisons of past with present abundances indicate that more than 90% of them have been lost in bays (70%) and ecoregions (63%). In many bays, more than 99% of oyster reefs have been lost and are functionally extinct.


They have supported civilizations for millennia, from Romans to California railroad workers (Mac-Kenzie et al. 1997a, 1997b). In 1864, 700 million
European flat oysters (Ostrea edulis) were consumed in London, and nearly 120,000 workers were employed as oyster dredgers in Britain. Shell piles from historical harvests in the southwest of France contain more than 1 trillion shells apiece, underscoring both the productivity of the species and the scale of harvest (MacKenzie et al. 1997b). In the 1870s, intertidal reefs of the eastern oyster Crassostrea virginica extended for miles along the main axis of the James River in the Chesapeake Bay; by the 1940s, these reefs had largely
disappeared (Woods et al. 2005). In many coastal areas, including the Texas coast, roads were paved with oyster shells (Doran 1965).


Over harvesting, Disease, invasive species. Have left populations slipping away.


More:

Thursday, March 8, 2012 Drought Suspected in Florida Bay Oyster Die Off.

1 comment:

  1. Here is a disturbing article on the Amazon rain forest. http://www.bbc.co.uk/news/science-environment-12356835

    ReplyDelete