The Arizona Game and Fish Department is spending $356,000 to increase the bass population at Roosevelt Lake. Curtis Gill, an Arizona Game and Fish Fisheries Program Manager, will talk about the effort to introduce a fast-growing Florida species of bass to Roosevelt Lake.
Ted Simons: The Arizona game and fish department is spending $356 thousand, to increase the bass population at Roosevelt Lake by introducing a fast-growing Florida species of bass. Here to explain is Curtis Gill, fisheries program manager at Arizona Game and Fish. It's good to have you. This is fascinating. I had no idea this kind of a problem existed out here. Why is this increase again needed, bass at Roosevelt Lake?
Curtis Gill: Well, over recent years we've noted a big decline in our fish populations there, we've noted about a 75% decline in our catch rates for large-mouth bass. About an 80% decline in our bluegill fish catching rates. Same with the black croppy, it's declined about 80 % and a decline in the condition of those fish.
Ted Simons: And why is that? What's going on?
Curtis Gill: There could be a number of factors. We've had gizzard shad showed up for the first time in Roosevelt Lake in 2007, that's an illegally introduced species that can compete with sport fish in the larva stage and can also -- They outgrow the gape size so quickly they're unavailable as forage. We've also had large mouth bass show up, it was first detected in 2011, though we haven't seen declines yet, it has been shown to cause declines in other states. We have decreasing water levels at Roosevelt Lake. It's been on the decline for the past three or four years during the spring, at the time when the fish are spawning. So that can dry out their spawning sites and you can have really poor reproductive classes. Additionally, we've also seen golden algae, we've had major fish kills at other lakes, back in the mid 2000s as result of golden algae, basically eliminating the small mouth populations at Apache Lake, so we noted our first fish kills at Roosevelt in 2012. We have a number of things that have collided at once there that have attributed to these declines in our fish populations.
Ted Simons: That's a big -- Roosevelt seems to me, was once considered a huge bass location, like one of the best in the country.
Curtis Gill: Yeah. It was noted as one of the best in the country, and it's our second highest in anglen use in the state.
Ted Simons: I want to go through these a little finer tune here in a second. But what about, I've read about this, other lakes and other parts of the country, cormorants are being blamed for lots of fish dying off and fish levels slowing. Are cormorants a problem at Roosevelt Lake?
Curtis Gill: Not at Roosevelt Lake. We do have some issues at urban lakes, like Tempe Town Lake and some other smaller urban lakes, but at lake like Roosevelt we don't have the population of cormorants we're seeing.
Ted Simons: Not that big of concern.
Curtis Gill: Not at Roosevelt.
Ted Simons: You mentioned gizzard shad, this is a fish invasive?
Curtis Gill: Yes.
Ted Simons: And it's pushing out the smaller shad?
Curtis Gill: Correct. Fred finch shad grow only sixth or seven inches maximum length, where as gizzard shad can grow up to sixteen to eighteen inches. And they can grow are terror eight inches within their first year of life. So they quickly outgrow the size most fish can eat them, sport fish can eat them.
Ted Simons: Even the large mouth bass, not as large a mouth needed?
Curtis Gill: That's one of the things maybe the Florida strain can help. They grow faster and larger than the northern strain we have, so it's possible they may be able to eat some of these gizzard shad.
Ted Simons: Talk about this Florida species. They're faster producing, what are they super bass?
Curtis Gill: No, they're just a strain of large mouth bass that typically do well in warmer climates. In Florida especially, they're known for their fast growth and then the size they can attain. And so Arizona, we have very similar conditions to some of these other states that have shown success with Florida strain large mouth bass like Texas and Oklahoma have had good success growing larger bass using the Florida strain.
Ted Simons: Are they as easy or are they more difficult to catch?
Curtis Gill: That kind of depends. There's been studies that shown they are a little more difficult to catch. But there's also studies that say they're basically the same. It's kind of mixed on the research that you read.
Ted Simons: When they're more difficult to catch, they're just smarter than the average bass? What's the?
Chuck Essigs: smarter --
Ted Simons: Just wary of lures?
Curtis Gill: Yeah.
Ted Simons: Are they more expensive than our Arizona homegrown bass?
Curtis Gill: They're fairly expensive. I don't know that they're more expensive, but bass in general are just -- They're right now I think the going right on large mouth bass is $20 per pound. So almost $20 a pound. They're fairly expensive.
Ted Simons: You mentioned the falling lake levels. Not as many nutrients, not as many hiding places. Talk about this, the idea that some artificial reefs, Arizona bass like to hide spring?
Curtis Gill: Many of our reservoirs in Arizona, they're typically fairly devoid of any kind of aquatic habitat. Roosevelt Lake does have a lot of submerged trees, things like that to provide habitat, but it's been down in elevation for three or four years, so it's only about 48% full right now. So when it's at that elevation these reservoirs were formed in steep canyons -- A riverbed basically, so there's not a lot of habitat. So one way we're hoping to help counteract the declines is give spaces for young fish to avoid predation from other fish and grow.
Ted Simons: I did read, tell me if I'm wrong, that the large mouth bass here in Arizona, they like to hide and attack and use some of these hiding places as opposed to this Florida species which is so big they say here I am I'm going to come get you.
Curtis Gill: Well, in all honesty I'm not familiar with that difference.
Ted Simons: All right. Maybe I read too much into the difference between those. The impact on local businesses, hotels, marinas, we can talk all we want about sports Fishermen and what they're going with, it's a concern, but there's a business aspect to this too.
Curtis Gill: There is. And we've actually been meeting with some of the local communities up there in that Roosevelt area, we've had -- Hosted three public meetings to date and we'll be hosting another in March to get their feedback on their perceived concerns, and what the issues they think, and how we can address those issues and try to help them out. Because they have voiced they have seen some pretty significant financial impacts from the fishing decline.
Ted Simons: You've mentioned this was kind of a perfect storm. Is that storm continuing, are conditions changing, is it kind of a looting goalpost?
Curtis Gill: The one thing we did most with the decline in other fish species, we did see a decline in our gizzard shad population. Whether that's going to be a long-term trend, I don't know. But as far as other factors, like the golden algae, unless we get precipitation the latter part of this winter, there's a really good chance we can have golden algae fish kill this summer because it's triggered by higher connectivity levels, so when we don't have the runoff in the salt river system those levels rise and we can see fish kills related to golden algae.
Ted Simons: Last question here, just out of my curiosity, how do you know how many fish are in the lake? How do you do samplings, how does that work?
Curtis Gill: We do sampling with electrofishing boat and gill nets. So electrofishing boat is our primary tool we use for sampling large mouth bass, that's the most effective way to do that. And basically it's just -- We have booms off the front of our boat that put a positive charge in the water and the fish are drawn to that, they come up, they're stunned momentarily, we net them, weigh them, measure them, and get good information on the species status basically.
Ted Simons: All right. So when are we going to see these Florida bass flopping around?
Curtis Gill: This spring. We're hoping to get them in this spring and stock up again in the fall with Florida strain large mouth bass and crappie and blue gill.
Ted Simons: We hope it works. Thanks for joining us.
Curtis Gill: Thanks for having me.
Curtis Gill:Program Manager, Arizona Game and Fish Fisheries;