What's Up With Lake Pleasant?

Guest · Feb 11, 2005

<center>By Denny Anderson</center>
 
Are the glory days of Lake Pleasant really gone? In the mid-90s Lake Pleasant was acclaimed as one of the top 10 bass lakes in the country. Now, Arizona fishermen talk about “The Problem” at Lake Pleasant. We just can’t seem to catch big largemouth bass at Lake Pleasant like we used to in the good old days. The good old days, when really big bass, 8’s, 9’s and 10’s, were being caught regularly out of the “New” Lake Pleasant. Is our opinion merely a convenient excuse based on our inability to adapt to the changing behavior of the big fish as some say? Or are the big fish still there and we just can’t catch them because they have “learned” to ignore our baits. Have the big fish changed their habits and now spend time in quieter, less fished areas of the lake? Unfortunately, there has been no hard evidence to support either side of the argument.

Attempting to resolve the debate, Arizona Game and Fish Department’s (AGFD) Scott Bryan published an article titled: “Where Have All the Big Bass Gone?” stating the opinions of AGFD on the Lake Pleasant fishery. In the article, AGFD states it believes that the “New Lake Effect” is mostly to blame for the diminished number of big bass at Lake Pleasant. The “New Lake Effect” began when a new dam was completed in 1992 and the lake reached its new full pool level in 1994. The new lake is 100 feet deeper than the previous lake and consequentially introduced additional nutrients into the fishery which in turn increased the availability of food for both forage and prey fish. As a result, there were more and bigger bass in the mid-90s. However, AGFD went on to say the Lake Pleasant reservoir is no longer “new” and it is starting to show the decreasing productivity and smaller fish that is typically found in an older reservoir. The “New Lake Effect” typically lasts only 6-8 years because as the reservoir ages, productivity levels decrease because nutrient levels coming into a lake are limited. Department electrofishing and gill net fish surveys show the number of bass has declined from 12 years ago but the bass are bigger and healthier than during pre-dam conditions. It appears that the size and number of bass is reverting to pre-dam conditions and the fishery that we see today is likely the one that will be seen tomorrow.Is this the definitive answer to where have all the big bass gone? No. Fishermen who say the big fish are still there argue that big fish are not as susceptible to being caught during electrofishing surveys and that gill nets won’t trap big fish if not placed at the right depth and location. Fishermen who believe the big fish are gone say that if AGFD maintains the big fish are gone as part of the natural “New Lake Effect” then the big fish either have died of natural causes or have been harvested by anglers and a upper slot limit on Lake Pleasant could have extended the life of this big fish fishery. There might be no definitive answer to the question “Are there less big bass in Lake Pleasant?”. Unfortunately there is no record over the last 10 years of every LM bass caught at Lake Pleasant. But you wouldn’t need a record of ALL the bass caught, just a sample that is big enough to be valid. Does such a record exist and would such a record support AGFD’s conclusion that the number of big bass in Lake Pleasant has declined?A quick search of the Internet provided the results of 49 bass tournaments held on Lake Pleasant between the years 1997 and 2002. Seven two-day tournament stories were found and those provided the big fish weighed on both days bringing the total number of individual tournament days to 56. WON Bass, BFL, Red Man, Five Star, BASS Federation, AllStar, BestBet, Chapman Dodge and a Tracker Championship are all represented in the data. 153 anglers participated on average.This provides a very large record of bass caught over the last six years at Lake Pleasant. Although the published articles do not frequently give the total number of bass, I conservatively estimate the total number of bass weighed at these Lake Pleasant tournaments over the last six years to be more than 18,000. The data below represents the 56 biggest fish of the more than 18,000 bass weighed by an estimated 8500 anglers.<div style="margin-left: -0.075in"> <table width="100%" border="0"cellpadding="6" cellspacing="0"> <tr> <td class="table1column1" width="30%" style="padding-top: 0in; padding-bottom: 0in" valign="top">Figure 1 is a plot of the Biggest Fish weighed in tournaments for the 56 dates. The red line represents the median of the data, 6.84 lbs. In other words, half the tournament big fish weighed more than 6.84 lbs, and half weighed less. </td> <td class="table1column2" width="70%" style="padding-top: 0in; padding-bottom: 0in" valign="top" align="center"> <img src="http://azbasszone.com/html/whatsupwithlakepleasant2.gif" alt="Figure 1" width="410" height="318" border="0"> Figure 1 </td> </tr> </table> Some observations about the data:· All four tournaments in 1997 and the next three tournaments in 1998 had big bass well above the median. More than 1.5 lbs above the median. · 18 of the 30 (60%) recorded tournaments from ’97 to ’00 caught a bass above the median. · 10 of the 26 (38%) recorded tournaments over the last two years caught a bass above the median. · Only 3 of the 17 recorded tournaments in 2002 caught a bass above the median.The true glory days of Lake Pleasant big bass is evident in 1997 and through the spring of 1998. The odds of a tournament weighing a bass over 6.8 pounds were much higher in 1997 to 2000 than in the last two years. Really big bass, those over 8 lbs, are absent from the records since March 2001.The data indicates that the size of the biggest fish caught during tournaments at Lake Pleasant has decreased over the last 6 years. From the huge 9.8 lb average big bass in 1997, Lake Pleasant is now yielding only a 6.1 lb average big bass. I would be very surprised if an actual sample of the bass population showed the same number of large bass over 7 lbs today as there were in 1997. </div>Thousands of angler days have been spent the last two years by hundreds of the same pro fishermen. (And those numbers include some of the best bass fishermen in the West as well as several BassMaster Classic participants.) Statistically, you’d think anglers of that caliber spending that much time on the lake would have come across a really big bass or two.Ah, but what if they found them and just can’t get them to bite? Its a commonly held belief that bass become conditioned to seeing the same baits over and over and won’t hit it. But there has been a steady introduction of new lures and new shapes and colors of plastic baits to fool fish. Five or six years ago rib worms, senkos, shakin’ worms, drop shot worms, and creature baits didn’t exist. A new technique for heavily pressured fish, drop shotting, has grown leaps and bounds over the last 3 years alone. If the big fish were in Lake Pleasant, the best fishermen in the state, in the West, and in the nation would consistently find them and put them in the boat. However, the data in Figure 1 shows that has not been happening. Or to look at it another way, in the 17 tournaments recorded in 2002, anglers logged more than 2400 days on the water, and caught more than 5000 bass without catching a single bass more than 8 lbs.The tournament results agree with AGFD’s conclusion that the number of big bass in Lake Pleasant has declined. Is this the definitive answer? The big fish are gone? Not entirely, there are still some really big fish in Pleasant as evidenced by the results of live bait tourneys, just not as very many as there were. I also see two trends in the data displayed in Figure 1 that are encouraging. 1997 and the spring of 1998, was a banner period for big fish, was followed by 18 months of hit-or-miss tournament angling. The years 1998 and 1999 were very inconsistent. For every tournament with a 7 or 8 pound bass, there was one with a 3 lb big fish. However, the year 2000 through the spring of 2001 would have to be called a really good period for big fish. And again that was followed by nearly a year and a half of so-so angling for big fish. In 2001 and 2002 there was one really big fish, some 7s but mostly 5s and 6s. As shown in Figure 1, the data indicates a good 18 months for big bass is followed by a tough period of 18 months. Is there a three year cycle for really big fish? If so, then next year would be another really good year for big fish in Pleasant.The second encouraging sign in the data is the year 2002. You’re probably asking yourself how can I say that when only three fish over 7 lbs were weighed in? True, but also only three big fish under 5 lbs were weighed in the same period. The data for 2002 is very consistent. The odds that a tournament would weigh a bass over 5 pounds was very high, 14 out of 17 did just that. Does this indicate a good population of 5 and 6 lb bass? If so then look for more fish over 7 lbs next year and perhaps the start of 18 months of good big bass fishing at Lake Pleasant. Only time will tell if the trends in the data come true. Lake Pleasant is a fascinating, complex lake environment, and the bass fishery is subject to the whims of both man and Mother Nature. As a storage facility for the Central Arizona Project (CAP), the water level can drop100 feet in just six months. Then raised either by nutrient rich runoff coming down the Aqua Fria River, or by nutrient poor water from the Colorado River system. CAP water has introduced Striped Bass to the lake and the potential impact to the bass fishery has yet to be determined. Heavy use by recreational boaters and fishermen will only increase as the metropolitan area of Phoenix grows towards the vicinity of Lake Pleasant. So many factors will affect the fishery that its hard to predict the future of largemouth bass in Lake Pleasant. According to tournament data, AGFD is correct in stating the numbers of big bass have declined. Let’s hope they are right again when they said the fishery that we see today is likely the one that will be seen tomorrow. Note: AGFD’s article can be found on-line at <a href="http://www.azod.com/topstory/Archive/2002/Where%20Have%20All%20the%20Big%20Bass%20Gone.htm">Where Have All The Big Bass Gone?</a> About the author <div style="margin-left: -0.075in"> <table width="485.2px" cellpadding="6" cellspacing="0"> <tr> <td class="table2column1" width="36%" style="padding-top: 0in; padding-bottom: 0in" valign="top"> <img src="http://azbasszone.com/html/whatsupwithlakepleasant1.gif" alt="The Author" width="120" height="120" border="0"> </td> <td class="table2column2" width="64%" style="padding-top: 0in; padding-bottom: 0in" valign="top">Denny Anderson lives in Arizona and has been an avid bass angler for the last seven years. With degrees in engineering and business administration, he takes an analytical approach to bass fishing. After retiring in January of 2002, Denny now enjoys being able to pursue bass whenever he wants. </td> </tr> </table> </div> This article was first published in the March, 2003 issue of <a href="http://www.basswest.com">Bass West</a> magazine. <div align="center"> © 2003 AZ BassZone.com </div>

What's Up With Lake Pleasant?

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