Last year, my colleague Ivy wrote about a proposed rule by NOAA to make shrimping safer for sea turtles in the Gulf of Mexico.

As you may know, all sea turtles in U.S. waters are on the Endangered Species List as either threatened or endangered. Since January 2010, NOAA has observed an increase in marine turtle deaths in the northern Gulf of Mexico. Sea turtle deaths can occur for a number of reasons, including disease, exposure to biotoxins or pollutants, ingestion of marine debris, vessel collisions, and fishery interactions. The proposed rule would have required turtle excluder devices (TEDs) on all shrimp trawling vessels, including boats that fish in-shore and in shallower waters than those currently required to use TEDs. These in-shore boats, known in the fishing community as skimmer and butterfly trawlers instead have to comply with “tow-time” restrictions, or limits to how long they can keep their nets submerged under water while fishing. Turtles drown when trapped in the nets too long.

NOAA has since withdrawn this proposed rule for multiple reasons, but primarily because the current design of TEDs did not seem to protect turtles effectively.

How is that possible?

The offshore shrimp boats that currently are required to have TEDs on their nets typically fish in deeper waters far away from the coastline. The turtles these boats encounter are generally adults and won’t get trapped in the back of the net thanks to the TED’s metal bars. However, the skimmer trawls fish in shallower waters, where juvenile turtles live. These juveniles are small enough to pass through the metal bars on the TED, get trapped at the back of the net, and potentially drown. To see how TEDs help turtles escape from nets, check out this video.

A 2012 NOAA study found that approximately 60% of the observed sea turtle captures in the skimmer trawl fishery were small enough to pass through the metal bars and could be susceptible to drowning without tow-time restrictions. NOAA stated that it couldn’t remove the tow-time restrictions, which are currently the only turtle protections in place, and replace them with TEDS that would not exclude small turtles from the shrimp nets.

Well, what’s wrong with the tow-time restrictions? To investigate the increased sea turtle deaths in the northern Gulf of Mexico, NOAA deployed scientifically trained observers to document sea turtle interactions within the northern Gulf’s skimmer trawl fleet. Previous studies have shown that tow-times aren’t effective. They are difficult to enforce — some peer-reviewed scientific literature suggests the tow-times are too long to avoid injury to sea turtles, and fisherman don’t follow them. However, increased observations on skimmer trawls in 2012 found that even with an observer on-board, over 64% of the tows exceeded the 55-minute limit.

Skimmer tow times relative to seasonal tow time restriction based on mandatory observer coverage of the U.S. Gulf of Mexico skimmer trawl fishery from May through August 2012

Scientists often assume that fishermen are extra diligent following rules like these when fisheries observers are on board. It’s like slowing your car down to the speed limit when a police officer is driving next to you on the road. In other words, the poor score of 35% compliance is probably even lower in the vast majority of the fleet when an observer isn’t on board.
So what happens now? NOAA has a two-fold plan:

Research: Rather than acting reactively after an observed increase in turtle deaths in the spring, NOAA is now proactively initiating aerial and on-water surveys before the 2013 shrimping season begins. NOAA will also continue to study interactions between turtles and the skimmer trawling fleet by continuing to place observers on skimmer trawls to determine the average amount of turtle interactions during a shrimping season. NOAA is also researching and developing new TEDs that will work for the smaller turtles typically found in shallower waters without clogging the fishermen’s nets with debris or causing a large loss in production.

Outreach and Education: NOAA will also provide more outreach and education to skimmer trawl fishermen about the existence and importance of complying with tow time requirements.

Following these research and outreach efforts, NOAA will present these findings and reconsider potential rule-making in the next couple of years. According to NOAA, the bottom line is that TED regulations will be coming to replace tow-time restrictions; at this point it’s not a question of if, but when.