Loon Biologist Praises New Lead Sinker Ban

Jun 3, 2016

A ban on lead tackle in New Hampshire has gone into effect, with the hope that lead tackle will stop killing loons. Lead tackle was the largest cause of loon mortality between 1989 and 2011. Harry Vogel is a senior biologist and executive director at the Loon Preservation Committee. He spoke with NHPR's All Things Considered host Peter Biello. 

How does the loon come into contact with the lead tackle—does it think its food?

There are several different ways in which loons can ingest tackle. And one is that the typical prey item for a loon might be something like the yellow perch, somewhere between four and eight inches long. But loons can occasionally swallow much larger fish. And once you get past that eight or 10 inch mark, you are running into a size of fish that could easily break an angler’s line. And when those fish break that line, it’s still trailing that length of line and the sinker, or the lead-headed jig that’s attached to it. And that fish is going to be a little bit slower than the fish next to it. It’s going to be behaving a little bit erratically because of that trailing length of line and the sinker. And that is the fish that a loon is going to zero in on as an easy meal. When it eats the fish, it also gets the lead sinker or the lead-headed jig.

Two other ways in which these loons might ingest lead sinkers: one is that as if you are looking to catch a fish, you may actually catch a loon instead, because a loon’s instinct is to strike at something as it’s flashing by it in the water.

The final way (which we used to think was the most common way and now we think is actually less common) is that loons will, because they have no teeth, swallow small spit shot and small stones. And they ingest those stones and they hold those in the gizzard (the muscular portion of their stomach) and those stones kind of act as surrogate teeth to grind up the fish that those loons have ingested. Every once and a while, instead of picking up a stone, they pick up one of these small spit shot lead sinkers and ingest those.

Is the lead poisonous to loons in the same way that’s its poisonous to human beings?

Lead is actually much more poisonous to loons and to other water birds than it is to human beings. And the reason why I say that is that if something like a raccoon were to swallow a lead sinker or a lead-headed jig that it found—and probably from time to time they do—the good news for that raccoon is that the lead piece is going to transit through its digestive system in about 24-48 hours. And it’s going to get a mild case of lead poisoning but it probably won’t be fatal. The difference is that loons and some other water birds actually hold onto those lead pellets. And so as they are holding them in that gizzard, in the muscular portion of their stomach, the grinding action against other stones that are in the stomach and the stomach acids dissolve enough of that lead to cause lead poisoning—fatal lead poisoning.

And that’s why instead of using lead tackle, you’re going to be encouraging sportsmen and women to be using tackle made out of tin or steel?

Yes. The good news here is that if that lead sinker or lead-headed jig is not made of lead, if it’s made of anything other than lead (and there are a huge number of things you can make these sinkers and jigs out of—that includes steel, tin, bismuth, tungsten, rubber, stone, these news composites of materials), any of those will be quite safe for those loons to swallow. But the smallest little split shot that you can imagine is enough to kill a loon within two to four weeks of ingesting it.

Reports indicate that 133 loons were killed by lead tackle between 1989 and 2014. That does not sound like a large number, but maybe it is depending on the population of loons in New Hampshire. Can you put this number in context for us?

Last year we had 291 pairs of loons throughout the state. And that still seems like a large number, and in comparison the number of deaths from ingested lead tackle seems very small. But to understand the impact of this on our loon population, you need to know a little bit about the life history of loons. Loons are long-lived animals. We are not exactly sure how long, but our best guess is about 25-30 years at this point. And they don’t begin to breed until they are, on average, six years old.

Once they do begin to breed, their reproductive success is very limited. They lay only one or two eggs, and the typical breeding success for a pair of loons in New Hampshire is about a half a chick per pair per year. And for any animal that has those life history characteristics, the key to maintaining a viable population is to keep those adults alive from year to year, so that they have many opportunities to reproduce themselves. So anything that affects adult survival of loons is something that we take very seriously at the Loon Preservation Committee, and you really don’t have to go very much farther than lead sinkers and lead-headed jigs to see the major cause of adult mortality of loons in New Hampshire.

What can sportsmen and women do, aside from switching the kind of tackle they use, to be mindful of loons when they are out in the wild?

Switching tackle is really the big one. We say all the time, “We are not anti-fishing at the Loon Preservation Committee.” In fact, we are routinely giving out non-lead jigs and non-lead sinkers to anglers that we encounter in our day-to-day work. And when we give presentations we are simply asking that when they do fish, they fish with something other than toxic lead. So treat the loons, treat other wildlife, treat yourselves to some new non-toxic fishing tackle.