Thursday, April 14, 2011

Eat More Striped Bass!

Maryland Department of the Environment raises the suggested maximum monthly consumption from 2 to 3 meals:
Under the new advisories, the recommended meal limits for the general population for smaller striped bass caught in the Chesapeake Bay increased by 50 percent, from two per month to three per month. Also, the advisories no longer include the “avoid” recommendation that had existed for women and children for certain striped bass.

The differences between the old and new advisories reflect a significant decline in the level of polychlorinated biphenyls (PCBs) in striped bass analyzed by MDE. Median PCB levels fell by more than half between fish analyzed from 2001 to 2005 and fish analyzed in 2009 and 2010 (see Table 2). MDE does not have the information needed to draw specific conclusions about the factors that led to these results, but the Department is encouraged by this data and will continue to track contaminant levels in striped bass and other fish.
 PCBs (polychlorinated biphenyls) are a group of about 200 compounds which were produced and used for many things in the 20th century.  They have turned out to be a serious contaminant of the environment, as they are extremely persistent, bioaccumulate in food chains, and have strong (but variable among species) toxic effects.

I'm pretty sure I know the reason striped bass from 2009 and 2010 have lower PCB concentrations than fish from 2001-2005.  PCB have not been manufactured or used in new products in the US since 1979, and even given it's persistence, it is degraded at a slow rate, and probably more importantly for fish, the sediments that it sticks to is being buried by new sediments with lower PCB concentrations.  The deeper the PCB are buried, the less likely they are to be reintroduced to the system by burrowing organisms, or sediment disturbances.
When filleting, MDE recommends removing fatty portions where PCBs tend to concentrate, including the belly flap and the dark meat along the side of the fillet. To evaluate this recommendation in striped bass, MDE compared PCB levels in non-fatty dorsal fillet samples to whole fillet samples. PCB levels were reduced by 75 to 91 percent in the dorsal samples, with the general trend being a greater reduction with increasing size of fish. These results support the value of the filleting recommendations and give Marylanders a good reason to consider how they prepare striped bass fillets, in addition to following the meal limits in the striped bass advisory.
 Good advice.  In addition to having higher PCBs the dark meat also tastes "muddy", and doesn't freeze as well, and the fillets are much tastier without it.  With a deft knife hand you can leave a thin layer of meat next to the skin and leave behind the dark meat next to the skin, and take a couple more strokes and remove the dark mid line meat.  

MDE also added Bluefish advisories:
MDE is also releasing an advisory for bluefish caught in Maryland’s Chesapeake Bay and Atlantic coastal waters (see Table 3). MDE has been able to obtain PCB data on bluefish smaller than 15 inches and greater than 28 inches but not on fish between 15 and 28 inches. Based on the available data for bluefish, MDE recommends a limit of two meals per month for bluefish less than 15 inches in length, but to avoid consumption of bluefish 15 inches and longer. These advisories could change as MDE learns more about the medium-size bluefish.
They must not have tried to catch 15-28 inch Blues, 'cause there sure are a lot of them.  Advisories should be considered additive; if you eat your bluefish, consider one of your striped bass quotas filled as well.

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