01/31/2012

The Maine Lobster Mystery

Simply stated, “Why do Maine lobster landings keep going up?” The shaky economy and the high cost of fuel have failed to make lobster fishers into millionaires, but¬† lack of lobster is not an issue. In 1994 we thought the record-breaking 39 million pound harvest, exceeding the previous record by 26%, was a fluke. By 2009 the harvest soared to 78 million pounds, in 2010 93 million pounds, and some predict even higher numbers for 2011. What is going on?

A while back I summarized the prevailing theories about why landings continue to increase. Reduction of predators (the cod fishery collapse), increase of kelp beds due to sea urchin fishing (kelp beds protect young lobsters) and finally, the inspired way lobster harvesting is managed by our Maine laws and fishermen. This last reason is kind of self-serving; after all, you don’t create an historic population boom by eating less of something.

Meanwhile, the scientists were baffled. For many years they warned that the fishery was on the verge of collapse, calling it “overfished” (Stock Assessment Review Committee Document 93; 18 July, 1993) . It’s easy to see how they would think this. For about a century, data suggested that a healthy harvest level was somewhere in the 20 million pound range. But a publication written in 1996 and available at the Maine Government website here proposes an interesting theory. While mentioning the usual reasons, lower predation, increased minimum size as amended in 1988,¬† and warmer water temperatures, it also presents a unique calculation. In 1994 lobster fishers raised their traps 39 million times:

If we assume each newly set trap contains on average about 2 pounds of bait, we can then calculate that Maine fishers used about 78 million pounds of bait in 1994.

In 1994 the lobster harvest was 39 million pounds, so that’s two pounds of bait per pound of lobster. The lobsters know how to work a handout. They enter the traps (underwater videos show them doing this with little difficulty) and unless they are big enough to not fit through the escape vent, they will not stick around until the trap is hauled. If they are too big, a notched female or an unnotched egg bearing female, they will be returned to the water. The few whose carapace measure from 3-1/4″ to 5″ are retained.

from Maine lobsterguide.pdf

So if this theory is correct, what we have here in Maine is a semi-domesticated fishery! They come into shallow waters in the spring, eat “our” food, mate, shed and grow. Without the artificial food input would there be nearly 100 million pounds of lobster? Think of it this way: a quick and dirty google search (USA Today) brought up a ratio of 5 pounds of feed for one pound of chicken and two pounds per pound of catfish, so it’s not unreasonable to think that bait is a significant factor in the increase. More landings result in more traps. More traps mean more feeding stations, and so more lobsters. In Nova Scotia traps are limited by law, and the harvest has leveled off.

While it’s hubris to suggest that our fishing methods are so well designed that we are able to produce more lobster than we can harvest, it does appear that an unintended byproduct of this fishing method (the bait) could be doing just that. So keep eating lobster. There are hungry mandibles to feed.

Late Word: The Ellsworth American reported on Feb 1, 2012 that the 2011 lobster harvest was 100 million pounds! Wow! The same article also reported that the 2010 total just for our Hancock county was 31.1 million pounds. Compare this to 11.6 million pounds caught in Massachusetts¬† waters in 2009. For our part of Maine, that’s 576 pounds of lobster for every resident!

Related Posts:

Filed under Acadia, Out on the water by on .