Mollusks that make you say "hmmm."


If you’re a follower of any Chesapeake conservation, or even just read newspapers in the local area, what you’ve probably seen over the past few days are a lot of headlines like these: “Virginia oyster harvest soars”, “Virginia oyster harvest up sharply in past decade”, and “Virginia oyster landings largest since 1989.” Time to celebrate, right?

Well, maybe not so fast. If you read these articles critically, there are quite a few gaping holes and a somewhat…fishy (oystery?) smell about them. Everyone knows the oysters in the Bay are struggling- right? Which is why it is so startling to read articles like the one from Northern Neck News:

“ Virginia’s oyster landings in 2011 were the largest they have been since 1989 and marked a tenfold increase over landings just 10 years ago. The news follows years of efforts aimed at increasing oyster populations in the Chesapeake Bay, which have been decimated by disease.

On Feb. 7, Gov. Robert McDonnell ® announced the boom that he said was fueled by the Virginia Marine Resources Commission’s use of a rotational harvest system, sanctuaries and targeted shell plantings on public oyster grounds.

The 236,000-bushel harvest in 2011 contributed $8.26 million to Virginia’s economy while 2001’s oyster harvest of 23,000 bushels only generated $575,000.”

The first thing that I noticed in the article was that the harvest of the oysters is being used to determine the strength of the wild oyster population. But the population of oysters and the amount of oysters harvested is correlation, as the economists say, not causation.

Another thing that seemed a little, well, “oystery”, was the fact that this announcement was being made by the governor (rather than the Virginia Institute for Marine Science, the National Oceanic and Atmospheric Administration or another scientific organization) in an election year. The oyster harvest, as the article mentions, has been in serious decline over the last decade and prior throughout the Chesapeake, and the prospect of a healthy oyster harvest and the financial impacts it effects are strong platform tools. While Virginia governors can only serve one term, other legislators in the state are stumping this year, and oysters make an environmental and economic two-fer, as far as campaign speeches are concerned.

So I decided to do some data hunting, and what I found was pretty confusing. First of all, Virginia uses bushels to tally their catch. NOAA defines the harvest in numbers of pounds sold. Comparing data from the two sources about the harvest over the last decade makes it difficult to draw similar conclusions, and major differences in just generally whether the catch was bad, good, or somewhere in between makes it even harder:

First, the data from Virginia as distributed by the Governor’s office, in numbers of bushels per year (I highlighted this year’s catch):

Then, data from NOAA (in pounds per catch). It stops in 2008 but still gives you a sense of the discrepancies:

They just don’t match up in terms of trends - at all. NOAA has Virginia’s worst harvests in 1993 and 2004. Virginia has their worst years in 1999-2001. NOAA actually shows a harvest spike in the years that Virginia reported as their worst harvest years to date! The year Virginia compared this year’s catch with, 2001, looks pretty bad on their chart, but things look relatively stable in 2001 on NOAA’s data. These are big differences! While I don’t have a NOAA report from 2011, I would imagine there are similar discrepancies between what Virginia purports to be their catch and the number other scientific organizations report. So, between the numbers angle, and the political rhetoric peppering the governor’s and other official statements, I am a little skeptical. For good reason: here is NOAA’s report going back as far as 1880 (Virginia’s information starts in 1957):

A little sobering, isn’t it? Even if you factor in minor disagreements about the  specific yearly catch, the overall impact is a little stunning. When I look at this graph, I wonder if it is a bit premature to be celebrating a return of a healthy oystering harvest, or to be anticipating bigger catches (and the revenue and jobs that go with them) anytime soon. There are up years and down years, but this shows us the catch is trending down, down, down, and has been since the end of the oystering boom at the close of the 19th century .

What are your thoughts in the news from Virginia? Are you a skeptic, like me, or an optimist who thinks this is the start of a whole new Bay?

Dip into a few of the articles on the “comeback,” look at some of the details, and then comment on your findings on this blog- perhaps you, gentle reader,  will notice a crucial argument for the governor’s announcement that I’ve missed.

Washington Post:

Daily Press:

Richmond Times-Dispatch: