Wednesday, April 21, 2010
Gray whale sightings are common in the waters along our coast around this time of year. For the second year in a row, a gray whale has been observed hanging out in San Diego Bay, which is relatively uncommon. The executive director for the Birch Aquarium joins us today to discuss what the whale might be doing in the bay.
MAUREEN CAVANAUGH (Host): I'm Maureen Cavanaugh, and you're listening to These Days on KPBS. For the second spring in a row, a migrating gray whale has been spotted spending some quality time in San Diego Bay. Last year, a whale, dubbed Diego, spent the better part of a month swimming and checking out the scenery between Shelter Island and Harbor Island. It's not clear how long this new visitor will spend in San Diego, but an up-close and personal gray whale sighting is always good news for tourists and for marine researchers. I’d like to welcome my guest, Dr. Nigella Hillgarth. She is executive director for Birch Aquarium at the Scripps Institution of Oceanography. And, Dr. Hillgarth, welcome to These Days.
DR. NIGELLA HILLGARTH (Executive Director, Birch Aquarium, Scripps Institution of Oceanography): Good morning, Maureen. Thank you. It’s nice to be here.
CAVANAUGH: I’m so glad you could come in. So, tell us, how common is it to see gray whales in our local waters around this time of year?
DR. HILLGARTH: It’s actually very common. They migrate south. Really, they get here about December, they go down to Baja and they have their babies, their calves, and then they migrate back up. And by April, you’re seeing the tail end of the migration back up to Alaska.
CAVANAUGH: I see. So this gray whale would’ve been on its way back up to Alaska but somehow it just wanted to spend a little time here.
DR. HILLGARTH: Somehow it took a detour into sunny San Diego, yes.
CAVANAUGH: Now, don’t these whales migrate in groups?
DR. HILLGARTH: Actually, quite a lot of gray whales migrate on their own or in twos and threes. Sometimes they can be seen in groups as big as 15 but they’re not always in pods like other whale species.
CAVANAUGH: I see. But do they keep track of each other or try to, you know, with, you know, those whale sounds that we hear so much about?
DR. HILLGARTH: Not so much. The family groups, yes, particularly the mother and calf. I mean, that’s very important that these young whales that have never migrated before keep in touch. But they’re not as vocal as some whale species like the blue whale, for example…
CAVANAUGH: I see.
DR. HILLGARTH: …or the humpback.
CAVANAUGH: So it could be that nobody else in the group knows that this particular whale is hanging out in San Diego.
DR. HILLGARTH: That’s right. That’s right.
CAVANAUGH: So what might have led this whale into San Diego Bay?
DR. HILLGARTH: Well, they do stay closer to the coast than just about any other whale species because they’re unique in the way that they feed. They’re bottom feeders. And so although they don’t normally feed during the migration, they probably navigate by it close to shore. So this one may well have just lost its way and thought it was still being close to the shore coming into the bay.
CAVANAUGH: Now as far as I know, there’s only been sort of a couple of sightings of this year’s whale in the bay. Do we know anything about this whale’s size or any speculation about its age?
DR. HILLGARTH: As far as I know—and I haven’t actually seen it, I’ve only looked at footage—it seems probably to be an adult. The one last year was only about 30 feet long so it was obviously a juvenile. Adult’s about 45 feet long. So that’s the speculation, that it’s not a very young whale.
CAVANAUGH: And what has the whale been observed doing in the bay? Does it just swim around? Or, as you say, it doesn’t seem to be eating, right?
DR. HILLGARTH: I don’t think it’s been observed to feed. It’s cruising around, having fun. Of course, it comes up for air every few minutes which is when we can get a good sighting of it. But it seems to be just checking out the bay at the moment, from everything that I’ve heard.
CAVANAUGH: I’ve read the term ‘spyhopping.’ What does that mean?
DR. HILLGARTH: That really means that it’s swimming quite close to the surface and coming up very frequently.
CAVANAUGH: I see. I’m speaking with Dr. Nigella Hillgarth. She’s executive director for Birch Aquarium at the Scripps Institution of Oceanography, and we’re talking about the migrating gray whale that’s been spotted spending some time in San Diego Bay. Now, you know, we love talking about this, we love looking at a gray whale who wants to be in the bay for a while, but are there any dangers that the gray whale faces? First of all, is this any indication that the gray whale is in trouble?
DR. HILLGARTH: It would depend. As far as I can tell, there’s no indication that this is a really thin whale. Often, if the – if the backbone is really showing that might be an indication that it didn’t get enough food before it migrated south and then is in trouble being very thin migrating north. And there have been whales that have died during the migration, often found further north, that were clearly very thin. There’s no indication that this one is actually underweight but it’s very hard to tell just from the footage we’ve seen. I think the other possibilities are that it could hit something in the bay or be hit by a boat. I think that’s of probably greater concern.
CAVANAUGH: What happened last year when that – the gray whale, Diego, was in the bay for such a long period of time? Was there a sort of a nice relationship between boaters and the whale?
DR. HILLGARTH: I think there was. I mean, people were really very respectful of Diego and kept a good distance from him. And he seemed really to be quite unfazed and unmolested by the boaters.
CAVANAUGH: Now I know that you want to clarify some of the speculation about what this whale could be doing and wouldn’t be doing in the bay. It does not pose any danger to the local seal or sea lion population, is that right?
DR. HILLGARTH: That’s absolutely right. This is a very different kind of whale from the so-called killer whales or orcas. This is a whale that filter feeds very small organisms. It filters the mud from the bottom of the ocean so it has – it’s called a baleen whale. It has this beautiful sort of filter system in its mouth so it couldn’t possibly harm – eat a seal, even if it wanted to.
CAVANAUGH: Now I would imagine that the bay in general is shallower than the open ocean. Does that pose a threat to this gray whale stay – spending some time in the bay?
DR. HILLGARTH: I’m sorry. Say it…
CAVANAUGH: You know that the bay is shallower than the ocean, are – would that pose any threat to the whale?
DR. HILLGARTH: I think it’s unlikely because particularly with this species, they are – because they feed in shallow water anyway, they’re very, very sensitive to depth and to where the bottom of the ocean is. So unless this is an in trouble or a sick whale, I don’t think the shallow water’s going to be a problem.
CAVANAUGH: Now you spend – I know that Birch Aquarium is very involved in whale watching expeditions and teaching people about whales and marine life. I wonder what kind of a learning opportunity this creates, having a whale spending time in San Diego Bay?
DR. HILLGARTH: Well, this is a huge learning opportunity. This is a gray whale really coming right to our doorstep. Normally, we have to take people out long distances and if they’re lucky they get a glimpse of the whale. Sometimes the whale may come close to the ship. But here, really you could even see it, hopefully, we could see Diego right from the shore, and, hopefully, this whale, if it chooses to stay. So it’s a wonderful opportunity for people to see a huge mammal up close and really one of the great joys of the ocean.
CAVANAUGH: Now we don’t know how long this particular whale is going to stay here, if it’s going to stay weeks, the way Diego did. But when it does finally leave the bay and it migrates up to Alaska, what is that cycle of migration? What will the whales do in Alaska?
DR. HILLGARTH: Well, as soon as they get back up, which will take them several more weeks, they will start feeding in large quantities of these small crustaceans that are these amphipods that are in tubes at the bottom of the ocean. And they’ve even begun to adapt a little bit to eat more of the krill, which is in the open ocean. And so they need to start bulking up right now so they’ll be eating nonstop for weeks before they start migrating back down in the autumn.
CAVANAUGH: What do we know about the gray whale population now? Is it changing in any way? Are they dealing well with any new challenges or threats to their population?
DR. HILLGARTH: That’s a really good question of how well they’re dealing with change because the climate in the arctic is changing. The sea ice is retreating and this means that the water is warming up and that the animals that the whales feed on are changing, too, and they’re changing distribution and amounts. And so there is a lot of speculation among scientists and a lot of research going on to see how well the gray whales are adapting and if this is going to really affect this population of gray whales which has come back from the brink of extinction so well in the last few years.
CAVANAUGH: Now, you know, we commonly hear, well, unfortunately, about incidents where whales beach themselves. This is not the same type of whale that does that, is it?
DR. HILLGARTH: Not so frequently, no. It’s unusual. We do sometimes find dead gray whales washing up to shore, especially in times when they haven’t been able to eat enough but this is not commonly something that happens to whales, gray whales, they don’t normally seem to have some sort of issue which causes them to continually beach themselves, which happens in other species.
CAVANAUGH: What other species do we see around San Diego? What other whales can we spot if we go on a whale watching tour or something like that?
DR. HILLGARTH: Well, we’ve been very excited this year to see a lot of fin whales, which are after the blue whale and the biggest mammal on the plant, up to about 70 feet long.
DR. HILLGARTH: 50 tons or more. Huge, sleek, very fast whales. And we’ve seen several of them off our coast. And they’re much more widely distributed worldwide than the gray whale but it’s very, very exciting to see one of those large animals, and we actually have seen more blue whales than usual. And this year we had a blue whale, at the end of the season, come very close to one of our trips. Very exciting to see the largest mammal on earth.
CAVANAUGH: Well, and what does that tell you? Is that good news for our local oceans or is it just a fluke?
DR. HILLGARTH: I think it’s very hard to say. It may be that those populations of whales are doing better. Certainly, fin whales are protected now from whaling. It may be that they’re just changing their distribution patterns. I think it’s certainly something we need to watch and, hopefully, get more information on, and we just don’t know enough yet. It’s certainly good for San Diego.
CAVANAUGH: Now, I’m wondering, you know, this is a kind of a loopy question but you said last year’s Diego whale was younger, this one is older. It couldn’t possibly be the same whale, could it?
DR. HILLGARTH: You know, that’s a really, really good question. Yeah, theoretically, it could. Absolutely. Maybe he thought he had such a wonderful time last year.
CAVANAUGH: Well, when we look at this whale, what is it that we should look for? Is there anything that, you know, if, indeed, he spends time in San Diego Bay, how should we observe this whale?
DR. HILLGARTH: I think it’d be really interesting to see if the experts can get close to him to see if he’s in good condition—or it may be a she.
DR. HILLGARTH: And if it is actually doing any opportunistic feeding because we don’t know just how much they do feed during migration when they have the opportunity, when they’re not just steaming full ahead. And I think how much he interacts with people in boats. I think there’s a lot to look for. It’s very interesting.
CAVANAUGH: Indeed, and so will you be taking a lot of pictures or documenting this in some way?
DR. HILLGARTH: Oh, yes. Our – some of our education staff and our naturalists are already trying to see him. And I shall – I love taking photographs. I’ll be out there myself if I can.
CAVANAUGH: Well, I want to thank you so much for explaining this visitor that we have in San Diego Bay, and we’ll be keeping an eye out to see how long this one stays. Thank you so much, Dr. Nigella Hillgarth. She’s executive director for Birch Aquarium at the Scripps Institution of Oceanography. If you’d like to comment on this segment, please go online, KPBS.org/thesedays. And coming up, could algae be the perfect biofuel? We’ll hear about the research going on in San Diego as These Days continues here on KPBS.