Harvesting Bluegill.

[Aquaman]

Just in case you were wondering, there's some pretty smart people out there.

The following quote is cut and pasted from Bluegill - Big Bluegill

It is from Bill Cody of Ohio who is, in my opinion, the preeminent bluegill mind in the U.S.

There are a couple of others who might be close, but nobody does a post like Bill Cody.

"Bluegill Harvest
The following discussion serves as more a detailed, background and review about harvest of bluegill (bgill, BG). Dr. Bruce developed his above summary of BG harvest for producing trophy sized bgill using much of the following fishery research and his practical experience. I have experimented with and studied management for growing big bgill for numerous years.

”Managing for big bluegill is more difficult than for instance creating a trophy bass fishery – Pete Jacobson MN DNR” (In-Fisherman May-Jun 1994).

Not a lot of detailed information on the proper harvest of bluegills exists in the common “easy to get” literature. Generalized guidelines for the proper harvest of BG are in several pond management booklets & books. Some of them recommend no harvest restrictions on bgill which in theory is designed to keep panfish numbers in control (Kansas Ponds 1987, Missouri Ponds Handbook). Recommendations in these booklets conclude that fishing emphasis should be on bgill harvest and not bass harvest. Some of the information on bgill harvest in these books assumes that the typical, relatively fertile pond contains a fishery of 250 to 400 total pounds of bgill per acre where water visibility would be 18”-24” for producing a productive fishery. These high standing crops of bgill will not occur or develop from natural foods in a pond that has clear water during most of the year i.e. where a white object can be seen 4ft to 12 ft deep. Generally the clearer the water the lower the standing crop per acre will be.

For years biologists believed it was impossible to over-harvest bluegills or other panfish and the best bgill regulations of harvest were NO regulations. Harvest as many as you want. Now newer information and research is emerging, and it shows that angling can “fish down” bluegill and panfish populations, especially the larger individuals. For reference the total body length of 6” (152mm, “quality”) is considered the standard minimal size of a harvestable bgill for table use (Novinger & Legler 1978, Anderson&Neuman in Murphy&Willis 1996).

It has been found that anglers can definitely harm a bgill fishery by removing too many larger bgill. In the first 30 days of a new bgill fishery in Maple Lk, MN, anglers removed 30% of the larger bgills. At Mill Lake MI. anglers harvested 13% of the 6”+ bgill in the first three days And at a new fishery in Third Sister Lake in MI, anglers removed 24% of the larger bgill in just 3 weeks. In another example at Mid-Lake WI, anglers removed 35% of the bgill over 6” in the 1st month of fishing and after two years of angling the total bgill mortality rate increased to 61%. Within 3 yrs most of the large bgill had been removed from Mid-Lake. Juvenile bgill often in northern states do not grow fast enough to rapidly replace the removed adults and as a result bgill populations pressured by heavy harvest become composed of fish mostly less than 6” long. When too many predators are removed, this often results in overabundant, small panfish.

It can take up to 7 to 10 years to replace or regrow a large bgill on natural food sources in northern waters such as MI, WI or MN (also see below). Schneider 1999 and Patriarche 1968 reported bgill lived up to 11 or 14 yrs in four MI lakes. Removing larger numbers (over harvest) of bigger bgills contributes significantly to poor size structure of a bgill population (Coble1988).

Several books recommend bgill harvest in the range of 3 to 10 lbs of bgill for every pound of bass harvested. Illinois Pond Mgmt guide recommends the amount of bgill harvested should be based on the pond fertility and harvested amounts ranged from 20 to 160 pounds of bgill per acre (120-640 fish). Ohio Pond Mgmt Handbook recommends for a properly managed trophy bgill pond that 100-150 (6”-10”) bgill can be removed per acre per year. Michigan Pond Mgmt booklet recommends to “follow two harvest rules: 1. remove as many under 6” bgill as you can
2. greatly restrict harvest of over 6 inchers.
This practice works to reduce overcrowding and helps the larger superior brood stock survive. Just as with bass, the biggest, fastest growing bgills bite most readily and tend to be caught first”. I think this is true up to a point. But after these caught and released fish get “hooked & jerked” several times, they tend to become hook shy and will often become cautious and more difficult to catch. However this behavioral trait may actually be beneficial especially in smaller ponds because it tends to protect these larger bgill from over harvest by you and poachers.



I definitely think that the number of bgill harvested per acre per year should be directly based on the pond’s fertility and the number of large bgill that are present. Schneider 1999 studied 11 of the better bgill lakes in MI. He noted that the “best” populations of larger bgill were predominately in lakes with low angler harvest of bgill.

Some fishery biologists are researching why and how some lakes consistently produce large bgills. Research is currently in the early stages but several features are emerging why some waters produce large bgills.

1. Presence of larger males tend to out compete smaller males who delay maturation and spawning while continuing to grow. Experiments (IL Natural Hist Survey) showed size and age of maturity is determined by how big the other males in the population are. When big males are removed, smaller males then become mature and establish a smaller maturation size group that is comprised of a smaller average sized individual than before. Thus presence of big males inhibits young males from maturing while absence of big males encourages younger smaller males to mature. Cody thinks several forms of intraspecific competition probably contribute to this phenomenon.

2. High mortality of small bgill (less than age 1) caused by an abundance of smaller, average, sizes of predators. Smaller predators are forced to eat small forage items. Up to 48.3% of the diet of small bass first year bass in Blueberry Pond MI was very large numbers of bgill at 7 – 15 mm long (Schneider 1999). He concluded that the slow growth of one predator species (possibly crowding & stunting) tends to cause that predator group to prey primarily on small bgill, for example, crowded, small bass. . Also cannibalism of fry or larvae of or by large bgill or another panfish can reduce intraspecific competition and allows faster growth of the remaining bgill YOY year class.

3. Presence of a “good” population of larger yellow perch in a Michigan pond with bgill also contributed a fair amount to age 1 mortality of bgill (Schneider 1999). He concluded however, that a high harvest of the y. perch can also lead to excessive bgill recruitment.

4. Low spawning activity or nesting success results in less need for predation and thinning of each year class thus improving growth rates. This can be accomplished by limiting the amount of spawning areas. As Bruce has mentioned, removing more adult female bgill than males will also help reduce the number of eggs laid in nests. Schneider (1999) concluded it is unlikely that bgill spawn more than once a yr in MI. Peak spawn was May 25-31 and at least some sporadic spawning occurred up to Aug 8.

5. Proper amount of macrophyte development (underwater weeds) provides refuge areas and production sites for abundant forage items for maintaing good growth rates of bgills. Overabundant macophytes can easily lead to over abundant panfish. In an exceptional fishery, Schneider (1999) reported that Michigan’s best large bgill fishery occurred in a unique, very weedy lake (83%coverage).

6. Diverse food web to accommodate the bgill’s generalist feeding tendencies which stimulates rapid growth of bgill. This includes an abundant food base of Daphnia (up to 2mm), Chaoborus, midge larvae in the limnetic or pelagic zone and numerous types and an abundance of adult & larval insects and other miscellaneous invertebrates in the littoral & sublittoral zones (in sediments and among macrophytes).

7. Bgill were found to have diet shifts and feed primarily in the different zones at different life or size stages (Schneider 1999). Good growth requires ample food for each size class in each zone so bgill grow well during all developmental size classes.

Once a pond or lake produces large bgills it seems very important that these largest bgills should not be over harvested. The presence of larger bgills in a fishery helps maintain a quality fishery and it apparently has an impact of the future development of the overall bluegill population structure (Schneider 1999). .

The dilemma becomes for the pond manager is how many and what size of bgill to remove. A normal pond can withstand some type of annual harvest because a natural mortality will occur each year. Bruce Condello, I, and other students of bgill, currently think the goal for a memorable or trophy bgill fishery should be to perform the larger part of the harvest from the midsize group (6”- 8”) of bgill and occasionally harvest only a very few (0.5-1/ac/yr) of those in the largest (9.0 or 9.5”+) category each year. I recommend that these fish should only consist primarily of bleeding deeply hooked fish. This will protect the largest bgill size classes and it will maintain a trophy fishery which is often the desired goal. With this harvest technique or philosophy and ample food, one should be able to grow bgill to 9.5” or maybe 10+” if they live 6 to 10 years.

Some (primarily anglers) will strongly disagree with the above philosophy and argue that the largest and oldest bgill should be readily harvested and utilized before they die naturally of old age. This is a debate for another topic and I will not dwell on it here. I do agree with our mentor, Bob Lusk (and many on the In-Fisherman staff) who promote their conservation philosophy about trophy bass, and I think it also applies to large bgills. This philosophy of preserving large fish is: “these are trophies or rarities of nature and should be appreciated and held in reverence, and they deserve to be allowed to live out their entire life span in the pond not in the frying pan”. This philosophy is quite difficult to implement in public waters where “meat fishermen” prevail, however it can easily be used in private ponds or water bodies with restricted access. When a pond manager uses this harvest philosophy, then this is why anglers will try their best and worst methods to illegally fish a pond that is full of memorable and trophy sized fish.


PBoss magazine discussed the basic concepts and philosophies of harvesting bgill, in the May-June2002 issue with an interesting cover story article (Selective Harvest, Pro Tips On Setting Effective Bag Limits),. It is recommended reading to provide good basic principles of fish harvest. In the article’s section on Bluegill Ponds, several authorities provided opinions regarding proper harvest, however few actual harvest numbers were reported which was probably due to the overall complexity of the topic.

Two of the best bgill lakes (large numbers of bgill greater than 8”-9”) in southern MI were studied for 6 yrs by Schneider 1999. Both lakes received low harvest of bgill and light overall fishing pressure. A few details of those fisheries follow:
Blueberry Pond, at 19.7ac, 22’ deep, ave secchi 6.8ft, 83% macrophyte coverage w/ plant growth to 8ft, hard-water - alkalinity 105mg/L, BLUEGILL 8”-9” long (123-333 fish/ac) comprised 62% of the bgill stock greater than 6”. Stock greater than 6” ranged from 214 -506 bgill/ac.
Dead Lake, at 56ac, 30ft deep, ave secchi 14ft, 41% macrophyte coverage w/ plant growth to 13ft, hard-water –alkalinity 114mg/L, BLUEGILL 8”-9” (16-44 fish/ac) comprised 13% of the bgill stock greater than 6”which ranged from 208 - 237 bgill /ac.

The three next best bgill lakes in MI that contained populations of large bgill were:
Third Sister Lake – 8”+ bgill = 68/acre; fishing pressure low
Mill Lake 8”+ bgill = 22/ac; fishing pressure none
Jewett Lake 8”+ bgill = 4.6/ac; fishing pressure average (0.23), fish by permit, after 5 yrs of angling catch/hr steadily dropped from 1.42 to 0.42.
From these data one can see the affects of fishing pressure which included bgill harvest..

From the info above, one can see a wide range can occur in the numbers of large bgill that a pond or lake can naturally produce or sustain due to primarily the fertility of each water body. I think the key to proper harvest of bgill, and yet maintain a proper balance, is being able to estimate on a fairly regular basis the relative numbers of bgill present in each size class. Once these numbers are known then a harvest quota can be established. I always tend to error on the conservative side of the number harvested, because I would rather be able to consistently catch larger fish, and harvest the medium sized individuals for the table compared to the opposite philosophy of eating the largest ones and as a result in the future catch fewer large fish.
Another harvest philosophy involves keeping primarily the largest bgills because they will soon die of natural mortality.

Since bgill grow rather slowly in many of the northern states excessive harvest of the largest individuals can easily result in the population getting skewed toward the next smaller size class that may be growing slowly. This leads us to the benefits of pelleted feeding which: 1. promotes faster growth of intermediate sized fish to replace the larger harvested fish, 2. it helps maintain high body condition factors of older fish and 3. it often helps in increasing the number of larger fish per acre. See CAUTIONS and TIPS below.

Ohio DNR’s High Quality Bgill Fishery
Ohio’s DNR operates a public, premier, bass - bgill fishery in Lake La Su An - 82 acre lake - NW Ohio. It is composed of primarily bass and high numbers of large quality sized bgills (6”-10”); angling is by reservation only. ODNR fish surveys estimate that 30% to 40% of the bgill are 6”+. Compare this percentage to Blueberry Pond above that had 62% of all the bgills greater than 6” were 8”-9” long. At this point, I do not have any Lake LaSuAn fish survey data for the numbers of bgill that generally were in each incremental size group of fish greater than 6”. Daily and annual harvest at LaSuAn is strictly monitored at a park ranger check out station. When annual fish quotas are met the harvest of fish is strictly curtailed and fish harvest essentially stops for that year or season. Annual harvest of bgill in this productive, hardwater lake is set at around 100 bgill (6”+) per acre per yr (abt 50-60lbs/ac/yr). This figure is estimated to be about 30% of the adult population (6”+). The natural mortality of this lake in unfished years was estimated to be a 36% mortality rate (L.Goedde verbal). I think if a stricter harvest quota was established as recommended by Dr. Condello and myself, this bgill fishery would go from very good to exceptional.


After I have gone through all this information, I still have not given you an actual number of bgill that can be harvested from a pond. I will assume a pond that has fairly clear water and are lower in nutrients similar to Bluebery Pond and Dead Lake mentioned above. Harvest rates for these waters were: Blueberry =2.5 fish/ac (1%); Dead Lake = 5.5 fish /acre (3%). Other fish (bass, perch) were also harvested at low rates from these waters. The point to note here, is that exceptional quality fisheries in low productivity waters are at a very high quality status, probably partly due to low harvest rates, adequate growth rates and proper balance. As most here know that read to this point, alkalinity directly affects the phytoplankton productivity which ultimately affects the poundage of fish that a pond can grow without artificial feeding.

To be conservative and error on the low side, I will assume moderately low alkalinity and low natural productivity for a pond, which I am guessing will have a standing stock of around 75 to 100 lbs of total bgill per acre.

Lets assume a bgill population / poundage is well managed with ample predation pressure on small individuals and the older year classes of bgill have a population skew of larger bgill of about 40% to be greater than 6”+ bgill. This assumes a lot of positives. With total standing crop of 100 lbs of bgill per acre, this results in abt 40 POUNDS of bgill/ac greater than 6”. I assumed the weight of bgill that are less than 6” to be in autumn or spring a fairly low poundage (abt 10lb/ac) due to predation and or manual thinning by you. If the BG are regularly fed pellets then the standing crop could be near 200 –330 lbs per acre.

If a goal was for harvesting 8”+ bgill this will probably cause the harvest number to be somewhat low. This is due to in normal population distribution, as the fish get larger, their numbers generally decrease which results in the fewest individuals in the largest, oldest size class. For example in Blueberry Pond and Dead lake, as noted above, the numbers of bgill in the largest size class of 10+” there were two individuals in Blueberry an none were found in Dead Lake.

My estimated numbers of bgill 8”-9”long/ acre for our natural food item clear water pond pond would be around 40 FISH/ac (20%) and for fish 9”+ long would be around 10 fish per acre (10%). Harvest about 30% to 40% of these numbers i.e. 15 to 20 fish per acre that are 8”+ /acre/yr. Keep good catch records and when the average size of fish you are catching gets smaller you need to look at making changes. Also when you catch or clean them, note the condition factor or relative plumpness of the large bgill. Skinny or thin fish indicate over crowding (food shortages & or competition) and more numbers of one size group should probably be harvested to provide more food for the intended individuals. A fish feeder will probably increase fish condition factors and fish catchability (CPUE) in vicinity of each feeder. However, with out proper management this could still lead to overcrowding and possibly survival or life span problems.

CAUTIONS and TIPS; 1. It will take time to grow your first batch of fish to 8” and 9” which could possibly require 4 to 6 years depending on your location, food source or size of the stocker fish. The fish growing season in MN or MI is considered to be three months (Flickinger&Buglow in Kohler&Hubert 1993). However, in a new pond with a rich, abundant food web for bgill one could see 2”-3” stocked bgill grow to 8” in 3 full yrs which would be excellent growth in a northern location. It should take fewere years in more southern states with a longer growing season. In WI and similar northern areas slightly better than average growth of bgill is 1yr=2-2.5”, 2 yr= 4.8-5.7”, 3 yr=5.0-6.4”, 4yr= 6.6-7.2”, 5yr= 7.4-8.0”. Ave growth of bgill in IL was also similar to the WI accelerated rates. Average MI growth rates are 1yr 3.1”, 2yr 4.3”, 3yr 5.4”, 4yr 6.6”, 5 yr 7.3”, 6yr 7.7”, 7yr 8.2”, 8yr 8.4”, 9yr 8.7”, 10yr 8.9”. Once a bgill reaches 8”, I think its growth rate will be only ¼” to ½” per yr depending on food supply and length of growing season. Expect overall bgill growth will very likely be at a somewhat slower rate AFTER the first several years in a new pond unless you supplement their diet with fish pellets. This is due to in the first few years of a new pond, the balanced numbers of stocked fish have the fastest growth rates compared to those when the pond fish populations stabilize (crowding) and a combination of numerous factors occur that can inhibit growth. Annually evaluating the forage food base and maintaining the proper fish density are important tasks for properly growing your future year classes of fish. I think hand feeding or at least one artificial feeder is very important for growing large plump bgill at least in one localized section of the pond. Note that feeding the fish pellets is not just about growing more and bigger fish. Feeding should be combined with proper harvest or implementing population adjustments to improve the condition factors of the remaining fish yet maintain proper community balance. Many pond owners miss this important point.

2. Monitor or evaluate annually the small and intermediate sizes of bgill and adjust numbers if necessary. I spend much more time fishing for the small and intermediate sized fish than for the larger fish. I suggest you learn how to build and use fish traps for evaluating your BG population.

3. Whenever fishing, continually monitor the relative plumpness of the bgill. When I clean fish, I always check for the amount of body fat. Thin fish are not getting enough to eat. Adjust densities as necessary.

4.. Spend a fair amount of time evaluating and tweaking the predator population so the majority of the predators are in the proper or targeted size groups to effectively crop bgill to meet your goals of producing big bgill.

The need to release large bgill depends on how many fish are harvested. Generally, releasing larger bgill helps sustain high catch rates of bigger bgill.

When you understand and implement these above facts, ideas and suggestions your BG population will respond by producing larger and higher quality bluegills."

[OldBaldGuy]

Fascinating info, Aquaman. I'm saving it to a Word file so that I can study it further.

Two parts really jumped out at me as I read through it the first time:

Bgill were found to have diet shifts and feed primarily in the different zones at different life or size stages (Schneider 1999). Good growth requires ample food for each size class in each zone so bgill grow well during all developmental size classes.

This tells me that I need to diversify my methods much more than I have in the past.

In WI and similar northern areas slightly better than average growth of bgill is 1yr=2-2.5”, 2 yr= 4.8-5.7”, 3 yr=5.0-6.4”, 4yr= 6.6-7.2”, 5yr= 7.4-8.0”. Ave growth of bgill in IL was also similar to the WI accelerated rates. Average MI growth rates are 1yr 3.1”, 2yr 4.3”, 3yr 5.4”, 4yr 6.6”, 5 yr 7.3”, 6yr 7.7”, 7yr 8.2”, 8yr 8.4”, 9yr 8.7”, 10yr 8.9”. Once a bgill reaches 8”, I think its growth rate will be only ¼” to ½” per yr depending on food supply and length of growing season.

I'd assume growth rates in Nebraska would be somewhat higher than these figures. Any idea how much higher? (The thought of gut-hooking a 10-year-old fish isn't sitting very well with me... )

[Aquaman]

OBG, I'm impressed.

You are exactly one person MORE than I thought would read this post.

Keep in mind that the variability in growth rates is staggering from one water body to another. Two different times I've been involved in sampling bluegill that were 10 inches and aged out at 4 or 5 years old. And neither one of these ponds had a feeder.

I'd be surprised if you've caught many bluegill that were ten years old. It may even be zero. It's just that when bluegill are in their typical high competition mode, invertebrate communities get mowed down pretty efficiently, and bluegill grow at a snail's pace. Hence the numbers you saw above--years and years to get to ten inches, if at all. But if you can put together that fast growth scenario--low competition, ample forage and low angling pressure on the best individuals, then bluegill can get to be 9 inches easily by their fourth year.

I was reeling in a beautiful 9 inch female the other day, and when I got it close to the dock it must have spit up a thousand little white colored skinny invertebrates. I layed down to look at them and out of nowhere, dozens of 3-5 inch bluegill popped up and started eating them.

Mmmmmmm! Things are always better the second time around.

[MA Machine]

I read that article and my brain sort of hurts now. I'm going to read it again after my ear stops bleeding. I do know I like the 7-9" slot limit on gills. It makes sense to me.

[bassnbaseball]

Wow.

[OldBaldGuy]

Got this message today from Daryl. Thanks, guy.

I'd assume growth rates in Nebraska would be somewhat higher than these figures. Any idea how much higher? (The thought of gut-hooking a 10-year-old fish isn't sitting very well with me... )

As always let me cite the disclaimers first--growth rates can vary a lot from one water body to the next. And of course we know that bluegill growth rates can be glacially slow in populations that are "stunted". Growth rates may not necessarily be faster in more southern population.

So, for some perspective, on "average" in a Nebraska pond, yes, it would take a bluegill about 10 years to grow to 8 inches. That would mean that an honest-to-goodness pounder would be at least a fast-grower probably at least 10 years old or it would be even older than that. Now in new ponds or newly renovated waters, the growth rates are likely much faster than that and those bluegills may reach 8 inches in half that time or even less.

We know that Nebraska's sandhills lakes are some of those habitats capable of producing exceptionally large bluegills. Our sandhill lakes have many of the characteristics that have been mentioned--relatively low densities of bluegills, bluegill recruitment likely limited by environmental factors, sufficient predator populations to reduce bluegill numbers, they are very productive and essentially all littoral zone (i.e. all shallow, bluegill food-producing water), they have very abundant and diverse aquatic vegetation, and they have very abundant and diverse prey base including a variety of large macroinvertebrates (i.e. aquatic "bugs"). Growth rates of bluegills in our sandhill lakes can be very fast. Honest to goodness 1-pound, 10-inch bluegills may reach that size in as little as 6 or 7 years in the best of our sandhill lakes.

Daryl Bauer
Lakes and Reservoirs Program Manager
Nebraska Game & Parks Commission
daryl.bauer@nebraska.gov

[Aquaman]

Actually, I'd like to know from Daryl if he's seen any truly ancient bluegill in his sampling days. You know, like 12 or 13 year old fish. I've probably aged, or assisted in aging somewhere around or over 200 bluegill, but haven't run across any real oldies like that yet.

An interesting point is that in a given population, a ten year old fish isn't necessarily going to weigh more than an eight year old fish. Sometimes the fish begin to regress, or go "geriatric" and the weights drop back a little.

[uglymike]

The only bluegills I harvest are "recycled", an 8" bluegill is good bait!!

[OldBaldGuy]

Originally Posted by uglymike

The only bluegills I harvest are "recycled", an 8" bluegill is good bait!!

Had to chuckle at your comment, Mike. The first time I carried my float tube over the hill to Redtail, there was a guy already there catfishing from the dam. When he learned I planned to fish for bluegills, he asked me to catch a few for him for bait. After I'd caught four or five, maybe 6-7" each, I paddled back to the dam to give them to him. He reeled in his catfishing line and I swear the gill he had been using for bait was AT LEAST 10"!

[fearnofish]

Originally Posted by uglymike

The only bluegills I harvest are "recycled", an 8" bluegill is good bait!!

Couldnt of said it better, but they are yummy little guys.

[LiquidSteel]

Originally Posted by Aquaman

OBG, I'm impressed.

You are exactly one person MORE than I thought would read this post.

I started to read it, but realized I should wait for the movie.... Or just go fishing and create the movie myself!

I do appreciate the info!

[Aquaman]

Originally Posted by LiquidSteel

I started to read it, but realized I should wait for the movie.... Or just go fishing and create the movie myself!

I do appreciate the info!

Actually it went straight to DVD.

[Sandbilly]

Great read Aquaman. Makes me very happy to live where I do.

We know that Nebraska's sandhills lakes are some of those habitats capable of producing exceptionally large bluegills. Our sandhill lakes have many of the characteristics that have been mentioned--relatively low densities of bluegills, bluegill recruitment likely limited by environmental factors, sufficient predator populations to reduce bluegill numbers, they are very productive and essentially all littoral zone (i.e. all shallow, bluegill food-producing water), they have very abundant and diverse aquatic vegetation, and they have very abundant and diverse prey base including a variety of large macroinvertebrates (i.e. aquatic "bugs"). Growth rates of bluegills in our sandhill lakes can be very fast. Honest to goodness 1-pound, 10-inch bluegills may reach that size in as little as 6 or 7 years in the best of our sandhill lakes.

Daryl Bauer
Lakes and Reservoirs Program Manager
Nebraska Game & Parks Commission
daryl.bauer@nebraska.gov

After the drought, Dr Willis, SDSU talked about stocking only bluegill in (I believe) he said School Lake, Valentine NWR with the intent to find out if stunting would occur without predation in these fertile sandhill lakes. Don't know if the Federal boys went for the proposal. Daryl?????

dc

[Fish Recycler]

For those who wanted it on DVD, here's a little video from Dr. Hal Schramm that speaks to this matter.

North American Fisherman Magazine - Video & Podcasts

My personal take, which is painfully vanilla but the only accurate point of view that I can stand by, is that achieving big bluegill by balancing harvest and C&R through regulation becomes a matter of individual water body management to be successful, and I think that all the experts who have shared here confirm that.

A single, across-the-board regulation on all waters won't work for all of them, but would work for some. Varying the management strategy by water body becomes confusing to anglers, difficult to enforce, and expensive to monitor and modify as needed.

So what's best? An educated angling public with a common goal is certainly a part of it, where regulation doesn't dictate the behavior, but observation of and response to the ecosystem from a stewardship mindset does.

[Slack Jaw]

Originally Posted by Slack Jaw

My buddy fishes a private ten acre pond and usually keeps 20-40 gills a year.He has never caught a gill under 9 inches in the past five years.This harvest rate has not negatively affected the gill population at all.The pond also has some very large bass which are always released.

I was reading all the info posted here and was wondering why the gills in said pond were so big and came to the conclusion that the pond has good overall depth, good cover, limited harvest, large predators, and a gazillion snails for forage.

[Sandbilly]

From you know who .


Let me ramble here for a bit, probably more than you wanted to hear, but hopefully it will all make sense when I am done.

There continues to be this discussion between waterfowl biologists and fish biologists about how many little duck food items can be produced in a body of water in the absence of fish. So one direction we wanted to take the sandhill lakes research with Dave Willis and his students was to look a little closer at that question. Last year Pony Lake on the Valentine National Wildlife Refuge was renovated to eliminate all fish. I believe the plan was to sample and monitor water quality and the aquatic organisms following that renovation for a year or two with no fish in the lake. This might answer some questions about the productivity of the sandhill lakes with not just applications to waterfowl production but also to fish production!

From the research we have done so far, we believe that panfish populations in our sandhill lakes do not function the same as panfish populations in pits, ponds or small reservoirs. You have probably heard me say 1,512,627 times that predators, especially largemouth bass are THE KEY to producing quality bluegills in Nebraska pits, ponds and small reservoirs. In a word you need the predators to control panfish numbers so that the remaining panfish have plenty of food to eat, grow fast and reach large sizes. From our research on our sandhill lakes it appears that you do not necessarily need to thin panfish numbers to produce quality panfish. Our sandhill lakes are so productive, have so many panfish food items, that you can feed them all--you do not have to thin their numbers. That and we believe that environmental conditions, weather and habitat conditions, might be the factors that limit panfish numbers in those sandhill lakes.

OK, so then the plan was to introduce fish to Pony Lake after a year or two of no fish. As I recall, do not quote me on this because I do not have the study proposal in front of me, but as I recall we had talked about introducing just bluegills. That would be a "test" of the theory that you do not need predators to control panfish numbers in Nebraska's sandhill lakes.

BUT,

All of that might be a moot point. Water levels this spring were high enough that we might have had fish re-invade Pony Lake already. I do not know the extent of that re-invasion, have not heard if any fish sampling has been done there since this spring, so we will have to stay tuned on that. Field research often does not go according to "plan".

Later,

Daryl B.


dc

[livnlrn]

How do you tell if a lake has sufficient forage to grow large gills? What can you do to increase the food sources in a lake naturally?

[Aquaman]

Here's another response from Daryl Bauer (He must have taken a liking to this thread)

Bruce,

Let me ramble in my pointy-headed fashion in answering your question.

I do not know how many fish, bluegills included, I have aged. I am sure it would be in the thousands. In addition we have an age and growth database of thousands and thousands of fish we have aged in Nebraska. We have documented bluegills up to age 13 from Nebraska waters. Ancient bluegills are possible, but not at all common. In fact in many waters it is rare to see bluegills older than age-6.

Now let me say something about aging fish, especially aging old fish. Fish to some extent have indeterminate growth--they continue to grow throughout their lives. Yes, there are some genetic limits, you are not going to have a 50-pound bluegill, sorry to you and "OldBaldGuy" about that, but fish can grow throughout their lives. As they grow their bony structures grow and the growth patterns in those bony structures are how we age fish. Scales are the most commonly used bony structure used to age fish. However, the older fish get the more difficult it is to achieve an accurate age determination from scales. Scales can erode over time and the older a fish gets the slower it grows; those are a couple of reasons it is difficult to determine the exact age of old fish from scale samples. For most bluegill populations, populations with relatively fast growth and few ancient fish, "reading scales" would be accurate enough to determine age and growth rates needed to make management decisions.

But if you rely solely on scales for aging you might underestimate the age of the oldest fish. If you want to know maximum age, then otoliths (i.e. ear "bones") are probably the best bony structure to use. The thing with aging fish by using otoliths is the fish have to be sacrificed and there is some prep. work and additional techniques to be mastered to "read" otoliths. "Reading" scales is relatively quick and easy compared to "reading" otoliths and the fish aged from a scale sample can still