September 28, 2018 — SEAFOOD NEWS — A recent technical memorandum from NOAA on right whale recovery in 2018 could push the agency to require new limits on trap fishing technology.

In short, the memorandum says that the measures adopted to reduce the number of rope lines in the water have backfired.

Although the number of lines to individual buoys have been reduced, the remaining trawl strings have more traps and stronger rope.

The result is that whales are suffering more for entanglements than they were before the new rules were introduced.

The memorandum says that “stronger rope contributed to an increase in the severity of entanglements.”

“Knowlton et al.(2012) showed that nearly 85% of right whales have been entangled in fishing gear at least once, 59% at least twice, and 26% of the regularly seen animals are entangled annually. These findings represent a continued increase in the percentage of whales encountering and entangling in gear, which grew from to 61.5% in 1995 (Hamilton et al. 1998), to 75.6% in 2002.”

“Rough estimates are that approximately 622,000 vertical lines are deployed from fishing gear in U.S. waters from Georgia to the Gulf of Maine. Notably until spring of 2018, very few protections for right whales were in place in Canadian waters. In comparison to recent decades, more right whales now spend significantly more time in more northern waters and swim through extensive pot fishery zones around Nova Scotia and into the Canadian Gulf of St. Lawrence (Daoust et al. 2018).

Taken together, these fisheries exceed an estimated 1 million vertical lines (100,000 km) deployed throughout right whale migratory routes, calving, and foraging areas.”

“Each vertical line out there has some potential to cause an entanglement. With a 26% annual entanglement rate in a population of just over 400 animals, this translates to about 100 entanglements per year.”

The problem is that sub-lethal entanglements can impact the reproductive success of the population.

“While serious injuries represent 1.2% of all entanglements, there are often sublethal costs to less severe entanglements. Should an entanglement occur but the female somehow disentangles and recovers, it still has the potential to reset the clock for this “capital” breeder. She now has to spend several years acquiring sufficient resources to get pregnant and carry a calf to term, the probability of a subsequent entanglement is fairly high, and this will create a negative feedback loop over time, where the interval between calving becomes longer. This is certainly a contributing factor in the longer calving interval for females, which has now grown from 4 to 10 years.

The implication of this technical report is that substantial reductions in entanglements will be necessary if the long term decline in the population is to be reversed, and under the endangered species act, NOAA will be required to evaluate any actions that increase harm or fail to mitigate harm to the right whale population.

This story originally appeared on Seafood News, it is republished here with permission.