This week, a time-honored American tradition makes its return: it's Shark Week. Started by the Discovery Channel in 1988, Shark Week is an annual weeklong block of exciting and educational programing revolving around the legendary ocean predator. It's also a great opportunity to highlight the multitude of threats that sharks face and bring attention to the importance of caring for our oceans. Jeff Kneebone, a senior scientist at the Anderson Cabot Center for Ocean Life at the New England Aquarium, spoke with GBH's All Things Considered guest host Craig LeMoult about local shark conservation.

Craig LeMoult: To start off, in general, how are shark conservation efforts going? We've been hearing for a long time about all these threats that sharks face from overfishing and from ocean pollution. Have we seen any any progress in terms of bringing back the global populations?

Jeff Kneebone: Well, that's a deep question, but to take in a 30,000-foot view, I think in some places in the world there have been pretty good success stories in terms of shark conservation. It's definitely a topic that's getting more and more attention, here in the United States as well as globally. When I get asked this question, it's really hard to answer generally because in my mind, it's very localized. Some countries are more conscious of it than others. Some policies are better than others. So it's hard to really give one answer. But in the United States, especially here in the East Coast where I live and work, I think there's been really good and successful conservation measures specifically related to the species that we have in Boston area, the sand tiger shark.

LeMoult: Can you tell us more about the sand tiger shark? And also, I know we have great whites off the coast as well.

Kneebone: Yes, we do. I don't study them, but sand tigers are something that I know a lot about and do study. I have been doing work on them since 2008, when I was a Ph.D. student at the University of Massachusetts. We're continuing to do a little bit of work on them in Boston Harbor, specifically in the Wollaston Beach area, where we think there might be a small nursery area for juvenile sand tigers that come up and spend the summer months in there when they're very young.

LeMoult: Wow. So, what's the population of sand tiger sharks like? Are there a threatened species?

Kneebone: Well, that's a great question. Over the last 30 years, the population has encouraged some declines, especially in the '80s and '90s. In 1997, they were declared a federally prohibited species by the U.S. government, meaning that they can't be retained or kept if they're caught in any fisheries. Just over the last 25 years it's been a conservation success story and we've seen the numbers rebound in Massachusetts, specifically north of Cape Cod. We've seen them emerge as a more common species, where maybe 20 or 30 years ago they were more rare, but now they're pretty common. In Boston Harbor, seeing the juveniles come up and use that area is just a testament to the recovery of the population.

LeMoult: What do send tiger sharks eat and are they any threat to people?

Kneebone: The ones that we see in Boston Harbor are juveniles, so they're about 3 to 4 feet long. Very much a small shark in the grand scheme of things. They like to eat small schooling fishes. They like Boston Harbor specifically because of the presence of menhaden, which are also called "pogies" or "bunker" by fishermen. That's just a schooling fish that's preyed on by a lot of different predators, like sharks and tunas. The juvenile sand tigers seem to really key in on them and occur in areas where those menhaden are in high abundance.

In terms of danger, they're not really, I would say, a dangerous shark, but unfortunately, there have been a couple bites that have occurred off of Long Island. Just people swimming in the surf and probably just were at the wrong place at the wrong time and perhaps even stepped on one of these small sand tiger sharks and the sharks responded with the bite. But it's never really a serious thing. These are small animals, again, 3 to 4 feet in length when they're juveniles.

LeMoult: The Gulf of Maine is known to be one of the fastest warming ocean regions on the planet. Are the warming temperatures in this part of the world changing things for sand tiger sharks or for other species?

Kneebone: That's a great question. Yeah. Just to give you a little background, sand tigers are found all along the coast. They occur from the Gulf of Mexico, basically all the way up into maritime Canada. That's happened historically. But one thing we have seen, say, in the last 20 or so years, is them move further north. So in the early part of the 1900s and then even in the '80s and '90s, they were primarily centered south of Cape Cod. But in the early 2000s and certainly now, we're seeing them occur much, much further north. They're becoming more common even in New Hampshire, in Maine and in Canada. There's a new story or two every year where someone up in downeast Maine or in New Brunswick, Canada, catches a juvenile tiger in a marsh and is all surprised because they've never seen these fish here before. So, it's very similar to what we're seeing with other fish species is that as the conditions in the Gulf of Maine warm, they become more hospitable for temperate animals like sand tiger sharks.

LeMoult: You know, as we mentioned before, it's Shark Week. It's become something of a cultural phenomenon over the years and I know it has its supporters and its detractors. What do you think? Do you think it's been beneficial for raising awareness of the plight of sharks?

Kneebone: In some ways, yes. Shark Week has certainly changed a bit since the time when I started watching it back in 1988, but I'll focus on the good. People like me who grew up in the late '80s and early '90s when it was really in its infancy, it really inspired me and I actually have some old VHS tapes sitting right next to me with some of the first ever Shark Week episodes that I taped or my parents taped for me back in the late '80s. Going back and watching them is really nostalgic and inspiring, and I've come full circle. So yeah, I just try to look at it that way and hopefully it inspires the next generation of marine scientists.