The Merits of Shrimp Trapping

When most environmentally-conscious Americans think of shrimp they conjure up negative associations of ecological damage to the ocean floor and bycatch that results from dragging for shrimp in the Gulf of Mexico, or shrimp farms in Thailand.

There is something that I need to clarify before progressing any further with this blog. When I speak of shrimp trapping I'm talking about one of the most environmentally-friendly fisheries around. Cap claims that trapping is "one of the cleanest fisheries" that he knows of. By "clean" he's referring to the surprisingly low amount of bycatch. The only species other than shrimp that I've witnessed in traps all season are juvenile lobsters and rock crabs. We throw them back in the ocean and they sink back into their happy little lives in the sea.

Shrimp trapping yields even less bycatch than lobstering due to very low species diversity of bycatch and due to lack of fish in shrimp traps. In terms of bycatch, shrimping is even "cleaner" of a fishery than lobstering, in that fish aren't caught in the traps. When many fish species are hauled up from the ocean bottom as quickly as they are in a trap, the rapid pressure difference causes the air in their body cavities to expand. They can't deflate and therefore float on the surface, unable to return to the benthos, likely to be plucked up by a gull. I don't mean to imply that bycatch is a problem in the lobstering industry. Lobstering is also an incredibly sustainable fishery both in terms of population recruitment as well as bycatch. But shrimp trapping is even better.

Furthermore, shrimp trapping leads to much lower ecological impact than dragging for shrimp. A trap only influences the area that it sits on, whereas a net sweeps the ocean bottom sometimes for hours in one "set" influencing the entire tract along the way.

Trapping is also more beneficial to the shrimp population than is dragging. Dragging begins earlier in the season (it began on December 1 in 2009, whereas we didn't set traps until late January) when the shrimp are still bearing eggs. When we first began hauling shrimp traps, the shrimp were still holding onto some eggs, but they weren't rounded out with eggs like early-season dragged shrimp. Now, at the peak of the trapping season, the shrimp have dropped their eggs. This means that they already reproduced. Those eggs will have a chance to hatch and grow into adults that will be caught in another two years. Therefore, I would go so far as to say that shrimp trapping is better for population recruitment than is dragging.

I think it is important to distinguish shrimp trapping from dragging (whether it is in Maine or in the Gulf) and from farm-raised shrimp. In general, Maine shrimp are much more sustainably

caught than shrimp from other places (domestic or foriegn). Even dragging in Maine produces little bycatch. There is a mandatory grate built into nets here called a "turtle-excluder" that releases many large fish and other big organisms. I don't know much about dragging, so correct me if I'm using the wrong terminology. Dragging in Maine also yields less bycatch than shrimp dragging in the Gulf simply because we have much lower species richness (species diversity and abundance) in Northeast waters.

Lastly, trapped shrimp are generally bigger, fresher and have a better "count" (number of shrimp per pound) since they are eggless. Trapped shrimp are still alive when they arrive at the dock, whereas dragged shrimp don't survive a long drag. I think they are the most beautiful shrimp around, but I'm a little biased.

In conclusion, shrimp trapping is a fishery of which very few Americans are aware. I think it is important to spread the word about it in our increasingly environmentally-conscious nation. It is a market that could be greatly enhanced if targeted at the right niches.