Dan Keller
UT DWR Fish Biologist
Gill Netting Results - November 2023
We conduct a wide variety of monitoring at Lake Powell however annual gillnetting provides some of our most useful data on fish condition and overall fish population trends. This winter we will be compiling a 3-year report looking at data from 2021-2023, I will share that report when it’s complete, for now, I wanted to post a few noteworthy findings. We know that some species are not good candidates for gill net sampling. Largemouth bass, black crappie, bluegill, and green sunfish tend to hold up in aquatic vegetation and structure and don’t cruise the shore at night making them less likely to get caught in a gill net. Historically, these species are caught in low numbers lake wide, this year was no different. We cannot say that there are low numbers of bass or crappie based on gill net sampling results. All of the monitoring techniques we use must be combined to make that assessment. However, we also know that on years with adequate flooded vegetation certain species have a productive spawn and greater survival creating a strong cohort (age class). The smaller (3/4 - 1”) mesh of our gill nets did detect a decent increase of young largemouth bass and black crappie. Two to three years from now the fish produced in 2023 will be large enough to really make a strong showing for anglers.
Striped Bass (Stripers)
During our netting at Good Hope Bay (Red Canyon) we found above average numbers of striped bass. Unfortunately, for us the fishing during our downtime was slow. When checking stomach contents, stripers were full of shad and we witnessed many shad schools simmering on the surface, however no striper schools showed up to turn the simmer to a boil. We figured due to the plentiful numbers of shad, stripers can quickly feed and get their fill in short order, they are not desperate and don’t have to work very hard to find shad, this can make fishing tough. If you’re lucky enough to be in the right place at the right time you will have very fast fishing for stripers that are in peak condition. I would rather catch 10 really healthy striped bass that fight hard and provide an excellent fillet than 100 fish in poor condition, like many things it’s a trade off right now, catch rates are likely down for most, but the fish are in great condition. It’s encouraging to see the recent reports of fast striper fishing on the North end of the lake. Many thanks to all of you providing those very useful reports.
While striped bass are well distributed lake-wide, the gill net survey has historically collected the most fish from the up-lake sampling site at Good Hope Bay. The mean total catch from 1981 to 2019 was 179 fish from Good Hope Bay compared with 114 from Wahweap, followed by 60 at the San Juan, and 43 at the Rincon. The graph below illustrates how striped bass numbers over the past 3 years (2021-2023) compares to historical means. The grey bars display the long-term mean catch of striped bass caught at each site between 1981 and 2019. The red circles indicate the mean catch over the past 3 years. The mean number of striped bass over the past 3 years is greater than the long term mean at all but one location (Rincon).
Smallmouth Bass prefer rocky habitat which is why they do so well at Lake Powell. Bass are caught less often than stripers because they move less and tend to stay on one stretch of shoreline instead of cruising the shoreline as stripers do. For this reason it is not wise to compare catch rate of different species, but rather year to year catch rate of the same species. In my reading of previous reports, I have learned it has been difficult to detect statistically significant trends in smallmouth bass numbers due to the variability of bass caught over the past 10 years. However, looking at smallmouth bass data from the past 3 years does show some interesting trends, most notable is the consistent increase of numbers in 2023 at all 4 locations. Again, this is not surprising given the good runoff we had in 2023, however its always nice to see consistency across monitoring sites. I also found it interesting that the greatest catch rates have come from Rincon over the past 3 years, this is a departure from the norm.
Blue = Wahweap, Red = San Juan, Green = Rincon, Black = Good Hope Bay
Based on my experience and reports I have received from anglers fishing is improving at the Rincon. This could be a result of the lower lake levels facilitating nutrients moving further down lake and creating higher primary productivity, this is something we will look more into when we analyze our zooplankton and water quality data. Sometimes sampling does not directly relate to sport fishing results, however, it has been my experience that smallmouth bass catch rates are down from what is “normal” while the overall size of smallmouth bass caught has improved. It appears our netting data tracks well with what anglers are experiencing across the lake. All the bass we caught in our nets (or fishing) were in prime condition with older age classes being well represented. During our 10 days on the lake our best fishing was not for stripers, but smallmouth bass. We got into a really good bite by trolling along the shoreline in Cha Bay with Norman Double Deep crankbaits, we didn’t try to tick the diver off the bottom like you would for walleye but rather tried to stay 5 to 10 feet off the bottom (less snags). We found smallmouth bass would come up from the bottom and strike the bait from underneath, we figured this was the case as many of the fish were caught on the front treble hook. As others have noted a fast troll, about 4 mph was the ticket. We estimated we caught between 40 and 50 smallmouth bass trolling, many were in the 2-2.5 pound range. Similar results are possible trolling a crankbait along a rocky shoreline lake wide.
Walleye numbers in recent years have been similar to long term trends. Shad are more abundant near the inflowing Colorado River. Previous work has proved that shad density is the limiting factor for walleye abundance. If shad numbers are high at a certain location during spring then young walleye survive in large numbers at that spot. Last year I noted the significant spike in walleye at Wahweap (see graph). The numbers in 2023 came back down to a more normal range. There are many potential causes of this spike, considering that numbers came back down its likely that many walleye moved down lake during 2022 due to low water conditions or simply moved into Wahweap following shad. Regardless, walleye populations continue to remain consistent and will continue to provide opportunity to those that target them.
This is getting to be a long post, hopefully some will find it useful. When planning a trip to Lake Powell this November the best option is to target the 20-40 foot depth along shoreline or near the back of a canyon. Trolling is the best way to find fish now but as the water cools stripers will seek deeper water and spooning will be a good technique. I plan to get out and fish around Wahweap before thanksgiving, I will be sure to post what I find. If you have questions or feedback please reach out to me, best to send me an email: Danielkeller@utah.gov
Happy fishing!
We conduct a wide variety of monitoring at Lake Powell however annual gillnetting provides some of our most useful data on fish condition and overall fish population trends. This winter we will be compiling a 3-year report looking at data from 2021-2023, I will share that report when it’s complete, for now, I wanted to post a few noteworthy findings. We know that some species are not good candidates for gill net sampling. Largemouth bass, black crappie, bluegill, and green sunfish tend to hold up in aquatic vegetation and structure and don’t cruise the shore at night making them less likely to get caught in a gill net. Historically, these species are caught in low numbers lake wide, this year was no different. We cannot say that there are low numbers of bass or crappie based on gill net sampling results. All of the monitoring techniques we use must be combined to make that assessment. However, we also know that on years with adequate flooded vegetation certain species have a productive spawn and greater survival creating a strong cohort (age class). The smaller (3/4 - 1”) mesh of our gill nets did detect a decent increase of young largemouth bass and black crappie. Two to three years from now the fish produced in 2023 will be large enough to really make a strong showing for anglers.
Striped Bass (Stripers)
During our netting at Good Hope Bay (Red Canyon) we found above average numbers of striped bass. Unfortunately, for us the fishing during our downtime was slow. When checking stomach contents, stripers were full of shad and we witnessed many shad schools simmering on the surface, however no striper schools showed up to turn the simmer to a boil. We figured due to the plentiful numbers of shad, stripers can quickly feed and get their fill in short order, they are not desperate and don’t have to work very hard to find shad, this can make fishing tough. If you’re lucky enough to be in the right place at the right time you will have very fast fishing for stripers that are in peak condition. I would rather catch 10 really healthy striped bass that fight hard and provide an excellent fillet than 100 fish in poor condition, like many things it’s a trade off right now, catch rates are likely down for most, but the fish are in great condition. It’s encouraging to see the recent reports of fast striper fishing on the North end of the lake. Many thanks to all of you providing those very useful reports.
While striped bass are well distributed lake-wide, the gill net survey has historically collected the most fish from the up-lake sampling site at Good Hope Bay. The mean total catch from 1981 to 2019 was 179 fish from Good Hope Bay compared with 114 from Wahweap, followed by 60 at the San Juan, and 43 at the Rincon. The graph below illustrates how striped bass numbers over the past 3 years (2021-2023) compares to historical means. The grey bars display the long-term mean catch of striped bass caught at each site between 1981 and 2019. The red circles indicate the mean catch over the past 3 years. The mean number of striped bass over the past 3 years is greater than the long term mean at all but one location (Rincon).
Smallmouth Bass prefer rocky habitat which is why they do so well at Lake Powell. Bass are caught less often than stripers because they move less and tend to stay on one stretch of shoreline instead of cruising the shoreline as stripers do. For this reason it is not wise to compare catch rate of different species, but rather year to year catch rate of the same species. In my reading of previous reports, I have learned it has been difficult to detect statistically significant trends in smallmouth bass numbers due to the variability of bass caught over the past 10 years. However, looking at smallmouth bass data from the past 3 years does show some interesting trends, most notable is the consistent increase of numbers in 2023 at all 4 locations. Again, this is not surprising given the good runoff we had in 2023, however its always nice to see consistency across monitoring sites. I also found it interesting that the greatest catch rates have come from Rincon over the past 3 years, this is a departure from the norm.
Blue = Wahweap, Red = San Juan, Green = Rincon, Black = Good Hope Bay
Based on my experience and reports I have received from anglers fishing is improving at the Rincon. This could be a result of the lower lake levels facilitating nutrients moving further down lake and creating higher primary productivity, this is something we will look more into when we analyze our zooplankton and water quality data. Sometimes sampling does not directly relate to sport fishing results, however, it has been my experience that smallmouth bass catch rates are down from what is “normal” while the overall size of smallmouth bass caught has improved. It appears our netting data tracks well with what anglers are experiencing across the lake. All the bass we caught in our nets (or fishing) were in prime condition with older age classes being well represented. During our 10 days on the lake our best fishing was not for stripers, but smallmouth bass. We got into a really good bite by trolling along the shoreline in Cha Bay with Norman Double Deep crankbaits, we didn’t try to tick the diver off the bottom like you would for walleye but rather tried to stay 5 to 10 feet off the bottom (less snags). We found smallmouth bass would come up from the bottom and strike the bait from underneath, we figured this was the case as many of the fish were caught on the front treble hook. As others have noted a fast troll, about 4 mph was the ticket. We estimated we caught between 40 and 50 smallmouth bass trolling, many were in the 2-2.5 pound range. Similar results are possible trolling a crankbait along a rocky shoreline lake wide.
Walleye numbers in recent years have been similar to long term trends. Shad are more abundant near the inflowing Colorado River. Previous work has proved that shad density is the limiting factor for walleye abundance. If shad numbers are high at a certain location during spring then young walleye survive in large numbers at that spot. Last year I noted the significant spike in walleye at Wahweap (see graph). The numbers in 2023 came back down to a more normal range. There are many potential causes of this spike, considering that numbers came back down its likely that many walleye moved down lake during 2022 due to low water conditions or simply moved into Wahweap following shad. Regardless, walleye populations continue to remain consistent and will continue to provide opportunity to those that target them.
This is getting to be a long post, hopefully some will find it useful. When planning a trip to Lake Powell this November the best option is to target the 20-40 foot depth along shoreline or near the back of a canyon. Trolling is the best way to find fish now but as the water cools stripers will seek deeper water and spooning will be a good technique. I plan to get out and fish around Wahweap before thanksgiving, I will be sure to post what I find. If you have questions or feedback please reach out to me, best to send me an email: Danielkeller@utah.gov
Happy fishing!