How often do you eat Tuna per month? Well, let me introduce you to a seafood that has dramatically lower pollution levels in its flesh, and comes straight from our local waters: The humble blue crab. Not only is it far better for the environment than eating fish that are caught by boats that must motor hundreds of kilometers out to sea (tuna), you can walk down the street and lay traps for tonight’s dinner.
So let’s get this pollution thing out of the way up front — one polluted fish is no better than another polluted fish, right? Local blue crab advisories suggest people eat no more than 6 crab per week, while tuna typically has a recommended maximum of about only a few servings per week. In both cases, they recommend women of childbearing age avoid eating them. So where am I going with this?!?
Well, published pollution measurements (PCBs) show that the flesh of blue crab has far lower pollutant levels than the gut (0.03 ppm versus 6.55 ppm), and lower than any other seafood tested in the harbor’s waters (get book chapter here, Chapter 28, Table 28.1). The method used to determine maximum serving numbers uses the entire organism, so neglects the fact that the pollution in different parts of the fish can vary. So, eating blue crab from the region’s waterways is actually relatively safe, as long as you only eat the white flesh. The bottom line is that these are short-lived species and they do not bioaccumulate pollution in their flesh like large, long-lived fish do.
Granted, pollution isn’t just about bioaccumulation, PCBs or mercury, it can also be pathogens that immediately make you sick. To avoid this, one should make sure the crab flesh is adequately cleaned (perhaps boil, not steam?) and avoid fishing within 2-3 days after rain events, when combined sewage overflows occur in many of our waterways.
None of this is terribly new … blue crab from our waters have been pawned off as Chesapeake blue crab due to their greater availability and size, as reported by the NY Times in 2006 (PDF: NYTimes 2006). And in many ways, it’s only been a question of where exactly you fish — many of the clams you purchase in the area are from the Hudson’s mouth, Raritan Bay, and are simply stored in clean waters for a few weeks before sale.
Personally, I’m not eating East River blue crab every week. I bought a new trap and have tried a few times at Hell Gate, near my apartment (my large crabpot doesn’t fit so well in an apartment, so it’s at NY Harbor School helping educate kids on Governor’s Island). But I am learning more and cautiously optimistic that our continuing water quality improvements and recovery from past decades of heavy pollution will make it safe to eat blue crab more and more frequently into the future.