How Valuable are our Big Pike?

[Tom7227]

This may not be the most popular place for my thoughts, but what the heck.

First of all I want to comment on what I have sensed is a way above average respect for the resource as well as other points of view on FM. I have done a little bit of surfing and come back to this HSOforum repeatedly because of the quality of the discussions.

That being said - look at some other sites, or even around this HSOforum, and you see an awful lot of folks bragging about the size of the fish they took - by hook or by spear. I'm not sure everyone practices selective harvest. I don't really want to bash someone for taking a large fish - that's legal and anyone has a right to do it. But go to the portion of this site where people are displaying photos of the fish they've taken.

I think part of the issue has to do with the amount activity - fight if you will - that you get angling that you don't get spearing. I don't spear. I've watched a friend do it once. My reaction is thinking about being able to play or fight that fish for 1 - 10 minutes with the risk of losing it vs. the spear -bang, it's dead and you bring it up.

It just doesn't sit right with me. It would be a different thing if it was a subsitence situation, but it's not anymore.

[Bowfin]

Tom7227 - Thank you for your view and keeping it respectful. I grew up fishing an awesome northern pike lake in central Minnesota. I "caught" my share of northerns of all sizes and it was exciting. When I was 14, my grandpa taught me to spear - the first fish I speared was 10 lbs. During my teenage years I speared and caught northerns of all sizes. My largest fish I speared was 14.5. The largest I caught was about the same size. Having done both I would rather spear a northern then catch one - whether it be my love of hunting or being sentimental who knows - the anticipation of a large "gator" drifting in excites me more than watching a bobber or holding a trolling rod.

That being said, the lake I cut my "spearing teeth" on became a trophy northern lake with a regulated slot of 24"-36" several years ago. I was forced to let the big ones go. In my conversations with the local fisheries manager, I was assured that this slot wasn't meant to inhibit spearing and although at the time I very much disagreed with the slot, I continued to spear the lake and abided by the slot limit. I had to become a "conservative spearer" - only spearing small fish to be sure I didn't spear one over 24". To date I haven't made a mistake although have speared a couple 23.5 inch fish. Since the slot was enacted the number of large northern we are catching and seeing has increased. I cannot deny that the slot seems to be working to produce a greater number of larger fish.

One last point - In Minnesota I think it is important and possible to provide a variety of northern pike opportunities. I have come to realize the value of providing for some trophy northern lakes (although it was hard personally because they chose the lake I spear on "not in my backyard mentality"). I also think it is important to leave other lakes open to spearing large fish. It concerns me a bit with talk of expanding slot lakes that someday it would lead to a statewide slot. Everyone who spears should have the opportunity to "go after the big ones" from time to time.

[Muskiefool]

This is a Big study AWH but it's a great depiction of what happens to the fisheries when you only harvest the Big fish, its worth the time to read.

LETTERMaladaptive changes in multiple traits caused by fishing: impediments to population recoveryMatthew R. Walsh1,2*, Stephan B. Munch1, Susumu Chiba1,3 and David O. Conover1

Abstract

Some over harvested fish populations fail to recover even after considerable reductions in fishing pressure. The reasons are unclear but may involve genetic changes in life history traits that are detrimental to population growth when natural environmental factors prevail. We empirically modeled this process by subjecting populations of a harvested marine fish, the Atlantic silverside, to experimental size-biased fishing regimes over five generations and then measured correlated responses across multiple traits. Populations where large fish were selectively harvested (as in most fisheries) displayed substantial declines in fecundity, egg volume, larval size at hatch, larval viability, larval growth rates, food consumption rate and conversion efficiency, vertebral number, and willingness to forage. These genetically based changes in numerous traits generally reduce the capacity for population recovery.

Introduction Go to:

It is unclear why some collapsed fisheries fail to recover even after harvesting has been reduced for more than a decade (Hutchings 2000; Hutchings & Reynolds 2004). By targeting the oldest, largest, and fastest growing individuals in a stock, fisheries generate strong directional selection favouring the survival of younger, smaller, and slower growing phenotypes. Recent studies have shown that single traits such as body size, growth rate (Conover & Munch 2002), or age/size at maturity (Olsen et al. 2004) evolve rapidly in response to intense harvest mortality. Because of genetic correlations, however, selective removal of large fish is likely to also cause indirect changes in numerous other traits (Lande & Arnold 1983). Smaller adult body size, for example, may be correlated with earlier maturation, and reduced egg size (Trippel 1995), fecundity (Bobko & Berkeley 2003), larval growth and viability (Berkeley et al. 2004a,. Such changes may accentuate the negative impacts of harvesting.

We conducted a harvest selection experiment on the Atlantic silverside (Pisces: Atherinidae), Menidia menidia, to assess the potential for genetic correlations to cause indirect changes in a variety of traits. We assayed a suite of physiological, meristic, and behavioural characters that either directly or indirectly contribute to fitness, and consequently influence the rate at which overexploited populations may rebound.

The Atlantic silverside is a harvested marine fish commonly found along the east coast of North America (mean annual landings in New York, from 1996 to 2000, were 20.5 MT). This species possesses characteristics common to many marine fishes including external fertilization, small egg size, high fecundity, spawning en masse, pelagic larvae, and schooling behaviour. Yet the Atlantic silverside has an annual life cycle making it one of the few harvested marine vertebrates for which multi-generation selection experiments are feasible. Six captive populations of M. menidia were subjected to one of the following three harvesting strategies (two replicates per treatment): large-size harvest (largest 90% harvested), random-size harvest (90% of fish harvested randomly), and small-size harvest (smallest 90% harvested). After four generations of selection, the yield (biomass) from large-size harvested populations decreased twofold compared with that of small-size harvested stocks wherein yield had increased (Conover & Munch 2002). Changes in yield occurred because large-size harvested fish evolved a slower growth rate and smaller size at harvest and vice-versa for small-size harvested populations. Using fish from the fifth generation of this experiment, here we demonstrate that harvesting the largest individuals caused substantial declines in egg size, larval size at hatching, rates of larval growth and viability, food consumption rates and growth efficiencies, willingness to forage under threat of predation, fecundity, and vertebral number.

Methods Go to:

Harvest experiment protocol

To ensure adequate genetic variation in the founder populations, c. 700 wild adult M. menidia in spawning condition were collected from Great South Bay, NY, USA on 5 May 1998. Fish were transported to the Flax Pond Marine Laboratory, Old Field, NY, USA and divided evenly among two 1800-L tanks supplied with filtered natural seawater. Between 100 000 and 200 000 eggs from these two spawning groups were collected and pooled over a 2-day period. Each generation was reared under identical environmental and density conditions using previously published protocols (Conover & Present 1990). Food was provided ad libitum to allow genetic differences in growth to be fully expressed. In each generation, the six experimental populations were reared in two 'phases' consisting of groups of progeny from each treatment spawned separately over consecutive intervals each spanning 10–20 days of egg collection. The phases represented duplicates of each line that were reared in separate seawater systems as a pre-cautionary measure in case of system failure or disease (neither occurred). Embryos were initially reared at 21 °C. Because M. menidia has temperature-dependent sex determination (Conover & Kynard 1981), larvae between 15 and 90 days old were reared at 15 °C to ensure a balanced sex ratio. Larval density was 175 per 19 L container. At 90 days, 550 juveniles from each phase and population were transferred to 700 L cylindrical tanks. Temperatures were then raised to 27 °C gradually over a 2-week period. When the average age of fish in each phase was 190 days, total lengths of all fish in that phase were individually recorded and sorted by size. The 90th (small-harvest populations) or 10th (large-harvest populations) percentiles of the size distributions were estimated and the appropriate harvest regime was then applied. In control lines, all individuals were also measured but then assigned randomly to either the harvested group or the spawning stock. The two phases of surviving fish within each population were then combined and photoperiod was altered to induce maturity. About 1.5 months later, eggs were collected from spawning tanks and reared as above, and so on for subsequent generations.

Statistical procedures

For all traits measured, differences between lines were examined using a two or three level-nested analysis of variance or covariance. The treatment effect (small, random, large-harvest), and replication (of lines nested within treatments) were the first two levels. A three-level nested anova was necessary for egg volume and larval size at hatch because the date in which the trait was sampled was incorporated. When size varied, it was included as a covariate in ancova.

Egg volume

Samples of 30 eggs per line were measured individually under a dissection scope. This procedure was performed six times.

Larval size at hatching

Hatch size was evaluated by measuring 30, 1-day-old larvae per population on five separate occasions. Failure to obey homogeneity of variances and normality necessitated the use of a Kruskal–Wallis test.

Larval viability

Three replicates, consisting of 50, 1-day-old larvae per line were stocked in 1-L containers. Larvae were fed ad libitum diets of brine shrimp nauplii and rotifers. After 10 days, the remaining living larvae were counted. This protocol was replicated for two separate dates of egg harvest. The data were arcsine transformed and the main effect mean squares were pooled as a result of a non-significant replication term.

Consumption rate and growth efficiency

Trials were conducted under unlimited and restricted ration conditions. The methodologies closely follow prior work (Present & Conover 1992; Billerbeck et al. 2000). For the unlimited food trial: three replicates of six fish per population were fed measured amounts of brine shrimp nauplii for 10 days at 23 °C. The initial lengths of the fish ranged from 18 to 20 mm. Each replicate was established from separate dates of egg harvest. Initial weights were determined by a previously established length–weight regression that consisted of 30 fish per treatment measured for length, wet weight, and dry weight. Nauplii were added, when necessary, to ensure ad libitum conditions.

After 10 days all fish were anaesthetized, and measured for total length, wet weight, and dry weight. Mean food consumption (mg day 1) was calculated as: (food offered – food retrieved)/(number of fish × number of days). Growth efficiency (%) was estimated as the total increase in dry weight divided by the total dry weight consumption of brine shrimp. For the analysis of the unlimited food trial, mean squares were pooled because of a non-significant replication term.

In the restricted ration trial, all lines were given an equal, yet limited, ration. Three replicates of six size-matched fish (mean length from each population: 18 mm) were fed brine shrimp nauplii at a ration of 50% wet fish weight. The remainder of the procedure is the same as above.

Vertebral number

Radiographs of 100 fish per line were taken using a Hewlett–Packard Faxitron Series 43806 X-ray system (50 kVP, 6 mA, 60 s) (Hewlett-Packard Company, Palo Alto, CA, USA) on Kodak Industrex type M film (Eastman Kodak Company, Rochester, NY, USA). All X-rayed fish were 190 days old and were randomly chosen from the fish that were harvested in each treatment during generation five (mean total length: L = 57.7 mm, R = 71.6, S = 81.7). Differences in vertebral counts were analysed with log-linear models. Treatment, line replication, and vertebral number were the factors in the analysis.

Response to predators

The willingness to forage under the threat of predation was evaluated in fish from the large and small-size populations during generation 6. The time of emergence from an experimental shelter after a simulated predatory attack was evaluated. In each trial, five size-matched silversides (mean length 34.8 mm ± 1.1 SD) were transferred to an experimental tank containing a small shelter. After an overnight acclimation period, all fish were chased with a model predator for 15 min until each individual consistently used the shelter to hide. Following another acclimation period (9 h), trials commenced by chasing the fish into the shelter for 15 min and food was then supplied via clear cylinders (1 m long, diameter 3 cm) placed at two corners of the tank. This procedure was replicated seven times.

Sigmoid curves were fitted to the trajectory of emerged individuals after the last chase in each trial, and the time (T50) that 50% of individuals emerged was estimated. T50 were log-transformed to standardize variances and improve normality, and compared among treatments using a one-way anova.

Swimming performance (Ucrit)

Trials consisted of six fish per treatment ranging from 18 to 22 mm. All protocols are based upon prior work (Billerbeck et al. 2001). Twenty-four hours before each trial, fish were size-matched, isolated, and withheld from food. After transferring fish to the flume, trials began with a 15-min acclimation period at a slow flow speed (5–10 cm s 1). Fish were then raised to their initial flow speed (13.5 cm s 1) and raised one body length (2.25 cm s 1) every 10 min. This stepwise increase occurred until all fish fatigued, defined here as failure to hold position and falling back upon the retaining screen. For each fish the time of failure and size were recorded. Exhaustion times were converted to critical speeds by the equation: Ucrit = V + (T /t × v), where V is the highest speed maintained for a full time interval, v the velocity increment, T the time at failure, and t the time increment (Brett 1964).

Results Go to:

Large-size harvesting caused significantly smaller egg volumes (Fig. 1a) and smaller larval size at hatching (Fig. 1b). In addition, estimates of coheritability between size at day 190, and egg size and size at hatch were both significant when maternal size was added as a covariate, indicating that selection on adult size has resulted in genetic changes in both larval traits irrespective of female size (Munch et al. 2005). Larval growth rates were also 25% lower in comparison with randomly selected controls [ancova: F(2,8) = 5.44, P = 0.032]. Furthermore, the probability of survival of these larvae to an age of 10 days was 61% lower than survival in randomly harvested lines (Fig. 1c).

Harvest selection on adult size caused significant declines in the consumption rates and growth efficiencies of juveniles in the large-size harvested lines. Under unlimited food conditions, the slow-growing, large-size harvested fish displayed significantly lower food consumption (Fig. 1d), and growth efficiency (Fig. 1e) when compared with randomly harvested lines. Additionally, even when all experimental fisheries were fed an equal but limited ration, the large-size harvested lines grew slower because of a 25% decrease in food conversion efficiency (Fig. 1f). Willingness to forage under threat of predation also evolved in response to fishing. When subjected to a simulated predatory attack, large-size harvested fish remained in hiding for a significantly longer period of time before resuming foraging (Fig. 1h).

Large changes in fecundity were observed. During generation 5, the fecundity in the large-size harvested populations was c. 60% less than the random-size harvested fish [eggs produced: large-harvest = 23 125; random-harvest = 64 250; small-harvest = 81 175; F(2,3) = 13.01, P = 0.033]. As fecundity is nearly linear with length (Conover 1985), an approximate relative fecundity was calculated based upon the lengths of adults after selection. The relative fecundity of the large-size harvested fish was 66% (± 13) less than the random lines, while the relative fecundity of the small-size harvested fish was 47% (± 20) greater than the random treatments.

Vertebral number also evolved in response to harvest selection. The large-size harvested populations evolved a significantly lower number of vertebrae [Fig. 1g; G = 61.126; P < 0.001].

Discussion Go to:

Fisheries theory assumes that harvest-induced reductions in population size will lead to increased per capita resources, and thereby increased fitness because of release from intraspecific competition (Grift et al. 2003). Implicit in fisheries theory, however, is the notion that changes in fitness are selectively neutral: no allowance is made for the possibility of evolution in response to harvest selection.

In marked contrast, our results demonstrate that a broad array of ecological functions spanning physiology, development, morphology, behaviour, and life history evolve in response to size-selective harvest. Early life history traits such as egg volume and larval size at hatch strongly influence survival. Given that larval mortality of marine fishes typically exceeds 99.9% (Houde 1987), and that the probability of survival is greatly enhanced by larger egg size (Rijnsdorp & Vingerhoed 1994), larval size at hatch, and faster growth (Pepin & Myers 1991; Pepin 1993; Houde 1997), slight reductions in these larval traits may have considerable consequences for recruitment to the juvenile stage. Decreased feeding rate, food conversion efficiency, and willingness to forage all reduce the per capita rate of energy flow and consequently reduce fitness. Finally, reductions in fecundity that occur as a consequence of smaller size will result in direct reductions in fitness.

Thus, despite the belief that increased food availability will increase productivity, we expect harvest selection to decrease the capacity for population recovery by decreasing traits that convert available energy into population growth. Such observations from wild harvested stocks are now accumulating (Sinclair et al. 2002; Barot et al. 2004).

In our experiment, we measured only a small subset of possible correlated traits. Based upon responses to selection in other taxa (Partridge et al. 1999; Garland et al. 2002; Rogers et al. 2005), it is likely that additional traits have evolved. For these reasons, the cascading effects of correlated responses may be far greater than are apparent from this study alone.

That fishing should cause maladaptive changes seems to defy a key principle of evolution. Should not selection favour genotypes with increased viability? The answer is yes, but under intense size-selective fishing, traits that would normally be favoured under natural conditions (e.g. fast growth, high feeding rates and large size) now reduce fitness. In essence, fishing warps the adaptive landscape by selecting against large size, which reduces the value of many correlated characters that ordinarily enhance fitness in unexploited populations. Hence, when fishing pressure is lessened, the survivors are maladapted for an environment where only natural forces prevail. As a consequence, the capacity for population growth in these remnant fish is greatly reduced.

Another paradoxical result is that the small-size harvested fish displayed apparent increases in fitness compared with the controls (Fig. 1). Why were the wild founders of our captive populations not already displaying maximum fitness? The answer is that excessive growth can be detrimental because of trade-offs with other traits. Very fast growing silversides exhibit decreased swimming performance (Billerbeck et al. 2001; Munch & Conover 2004) and a higher susceptibility to predation (Lankford et al. 2001; Munch & Conover 2003). The founders of our experiment came from an intermediate latitude where selection favours a moderate rate of growth. This experiment demonstrates that small or large-size harvest can shift the balance of selection away from the local optimum.

Our results warn that evolutionary responses to harvesting will generally slow the recovery of over-exploited fisheries. Although some of this trait variation may represent phenotypic as opposed to genotypic correlations with size, declines in egg volume, larval size, and fecundity are important from a fishery management perspective regardless of the mechanism responsible. As long as variation in size has a genetic component, the syndrome of undesirable traits that are associated with small size will continue to adversely affect fisheries until large size becomes re-established in the population. How long that would take is unknown. However, because fishing mortality is typically far greater and more selective than natural mortality, the evolutionary reductions in size and correlated changes demonstrated here are likely to persist for some time, even after fishing is halted. We are currently investigating this by continuing our experimental populations with a reduced harvest regime.

Although precise predictions of the response to harvest selection will require a thorough understanding of the genetic covariance structure, some qualitative information about likely paths of evolution may be obtained from the pattern of local adaptation in the wild. Slow growing silversides from low latitude populations exhibit decreased consumption rates and growth efficiencies (Present & Conover 1992; Billerbeck et al. 2000), lower fecundity (Klahre 1997), and lower vertebral counts (Billerbeck et al. 1997) compared with high latitude conspecifics. Thus, the pattern of trait correlations that emerged in response to harvest selection mimics that observed among populations of silversides from different latitudes and demonstrates that the observed changes in large harvested fish are not likely experimental artefacts. This parallelism of genetic correlations within and among populations is common (Schluter 1996) and may be used to establish baselines for predicting evolutionary responses to harvest selection across stocks.

Commercially valuable species typically live for many years, have overlapping generations, and are harvested in a less precise manner than our experimental fisheries. As a consequence, similar responses in wild fisheries are unlikely to be as rapid. Yet evidence documenting phenotypic change for comparable traits in wild fisheries is accumulating (Rochet 1998). Moreover, selective breeding of economically valuable fish species for the purposes of aquaculture have repeatedly demonstrated that many of same traits measured in this study, including egg size (Gall & Neira 2004), fecundity (Su et al. 2002), consumption rate (Mambrini et al. 2004a), food conversion efficiency (Thodesen et al. 1999), and even feeding behaviour (Mambrini et al. 2004b) are also genetically correlated with size. Thus, we expect similar changes to occur in harvested populations, although at a rate commensurate with the generation time of the species in question and the intensity of selection imposed by the fishery.

Of perhaps greater importance are the reasons why some fish stocks fail to recover and others have proven to be quite resilient to exploitation (Hutchings 2000; Hutchings & Reynolds 2004; Hutchings & Baum 2005). We suggest that recovery time may be determined in part by the period and intensity of exploitation to which a population was historically exposed; prolonged exposure to intense selection would increase the likelihood of harvest-induced evolution and thus increase the time required for populations to recover. For example, Atlantic cod, has been harvested for at least 200 years, experienced genetically based declines in fitness related traits (Olsen et al. 2004), and exhibited a little rebound after considerable reductions in fishing. In contrast, similar species with shorter exploitation histories have rebounded in response to diminished harvesting (Hutchings & Baum 2005). This pattern, however, is merely suggestive, and more work is needed to clarify the disparate roles of harvest selection, life-history, community structure, and environmental forcing on the observed differences in recovery.

Many fitness correlates decreased as a result of harvesting the largest individuals in the population. These correlated responses could be indirect responses to a harvest-induced decline in maternal size or adaptive responses to the new fitness landscape. Regardless of the mechanism, they decrease the intrinsic capacity for the population to rebound under natural conditions. A new Darwinian fisheries paradigm is needed in order to account for such impediments to recovery and to ensure sustainable yields over evolutionary time scales.

Acknowledgements Go to:

We thank D. Reznick, J. Arendt, and three anonymous referees for comments on the manuscript that greatly improved its content; and E. Hillebrand, C. Knakal, and numerous members of the Conover Lab for technical assistance. Supported by grants from the National Sea Grant College Program of NOAA under award number NA86RG0056 to the Research Foundation of Stony Brook University for New York Sea Grant, the National Science Foundation (OCE-0081916), and the Pew Institute for Ocean Science of The Pew Charitable Trusts. SC was additionally supported by the Japanese Society for the Promotion of Science. The views, expressed herein, are those of the authors and do not necessarily reflect the views of these sponsoring organizations.

[Tom7227]

I'm not able to absorb a PhD level treatise at this time. One thing does strike me however - how can some legislator stick his/her nose into something as complex as this and even begin to claim to know what they are talking about. People are very quick to criticize the DNR. However it ain't as simple as some would wish. Don't want to hijack this thread but it sure gives you something to think about.

[Scott M]

 Originally Posted By: Bowfin

Tom7227 - Thank you for your view and keeping it respectful. I grew up fishing an awesome northern pike lake in central Minnesota. I "caught" my share of northerns of all sizes and it was exciting. When I was 14, my grandpa taught me to spear - the first fish I speared was 10 lbs. During my teenage years I speared and caught northerns of all sizes. My largest fish I speared was 14.5. The largest I caught was about the same size. Having done both I would rather spear a northern then catch one - whether it be my love of hunting or being sentimental who knows - the anticipation of a large "gator" drifting in excites me more than watching a bobber or holding a trolling rod.

That being said, the lake I cut my "spearing teeth" on became a trophy northern lake with a regulated slot of 24"-36" several years ago. I was forced to let the big ones go. In my conversations with the local fisheries manager, I was assured that this slot wasn't meant to inhibit spearing and although at the time I very much disagreed with the slot, I continued to spear the lake and abided by the slot limit. I had to become a "conservative spearer" - only spearing small fish to be sure I didn't spear one over 24". To date I haven't made a mistake although have speared a couple 23.5 inch fish. Since the slot was enacted the number of large northern we are catching and seeing has increased. I cannot deny that the slot seems to be working to produce a greater number of larger fish.

One last point - In Minnesota I think it is important and possible to provide a variety of northern pike opportunities. I have come to realize the value of providing for some trophy northern lakes (although it was hard personally because they chose the lake I spear on "not in my backyard mentality"). I also think it is important to leave other lakes open to spearing large fish. It concerns me a bit with talk of expanding slot lakes that someday it would lead to a statewide slot. Everyone who spears should have the opportunity to "go after the big ones" from time to time.

I put a lot of stock into a statement like this. It tells me that someone can make short-term sacrifices for long-term gain, and for that I totally give Bowfin and spearers like him credit. They are still able to spear on lakes with slots, they are just careful about how they do it.

Know that you will never see a statewide slot. The anglers are against it, the spearers are against it, and the management agencies are against it. The slot limits in place on certain lakes are tools from the fisheries management toolbox...they are trying to work on a problem in order to get a desired outcome. They don't always work but they are an experimentation and the only way to even try and get results is to do just that- try. You will never see a statewide slot. Minimum size limits cause lots of stacking (oodles of fish approaching the threshold that are too small to keep) and stunting. Maximum size limits are usually for trophy only lakes. A statewide slot would work great on some lakes, not on others, which is why you would never see it.

[shooter_mcgavin]

Anybody feel like reading and summarizing that study for us?

[shooter_mcgavin]

 Originally Posted By: merkman

 Originally Posted By: shooter_mcgavin

My point is that most spear-fishermen seem to target the big ones.

I agree to disagree.

At the top of this forum is the 2007-2008 Darkhouse Pictures thread. After scrolling through that, I wonder how you could believe that most spear fishermen target small northerns, and let the big ones swim by.

Its interesting that, posted elsewhere, an artice citing the benefits of selective harvest is generally well-received. However once posted in a forum devoted to spear-fishing, the article is disected and ridiculed, citing "misleading information". Might this be out of fear of future regulations which would not allow people to spear big fish?

Let me just add that spear fishing as a sport, doesn't bother me one bit. In fact, it sounds pretty fun. I'd love to spear a few snakes for pickling (never tried them pickled but hear people talk about it all the time). The problem I have is large pike being targeted by most, which I believe has a dramatic affect on a fishery.

[bassNspear]

 Originally Posted By: shooter_mcgavin

At the top of this forum is the 2007-2008 Darkhouse Pictures thread. After scrolling through that, I wonder how you could believe that most spear fishermen target small northerns, and let the big ones swim by.

The reason that your seeing the bigger fish is becuase when a person spears a fish of that size, there going to show it off

[AWH]

Bass N Spear,

I hate to speak for someone else. But I think that's exactly his point. Nothing wrong with showing off the fish that you catch or spear. But it's impossible to show off a big fish if you "let it swim", which I believe, was shooter's point.

I may not agree with spearing a big pike. But if you choose to do it legally, great. If you choose to let them swim and only spear the small ones, that's great too. What I find bothersome is the folks that will argue that they don't spear big fish and then you see them showing off one (or several) of those big ones.

Muskiefool, thanks for posting that study. When I have more time than I have right now I'm going to be sure to read it!

Aaron

[bassNspear]

I understand what your saying. There is nothing wrong with spearing big fish at all. And theres nothing wrong with smaller fish as well. You have to remember, spearing smaller fish, will help the population in a lake so it dont get over populated.

Every single person that spears, somewhere down the line, will spear a big fish. There is no doubt about it. Iv speared big fish as well. People have to understand that its going to happen. Its just like tip up fishing, its going to happen.

[browning_gold]

I spear a lot of small fish that I would consider good eaters. But I will be the first to admit that any fish that I would consider big that comes into my hole does get speared...

[Tom7227]

I've spent a lot of time reading the various threads on the spearing/angling debate.

I, and others, have suggested that people go and look at pictures on FM as proof that spearers target big fish. The hole in that logic? How many people post pictures of the little fish they caught? I don't think that's the way it works in any forum on any subject. Show me the medal, the rack, the length, the report card. You don't advertise failure or mediocrity.

In a class I took - maybe advanced hunter ed - there was a section about the four stages of being a hunter. It was something like 1 shooting anything that flies 2. seeing how many you can get 3. getting into the ID, habits, habitat etc. 4 sitting back and watching most of the time and not pulling the trigger very often. The point that was stressed was that every hunter goes into at least one or more of these phases. Some stay in one their whole life, some move to others. But most importantly to those who enjoy the outdoors is the need to realize that there is nothing good nor bad about any one phase. A 4 is not 'better' than a 3.

Perhaps this needs to be applied to the issue of spearing vs. angling. Can it be thought of in terms of who is superior the rifle hunter, the person who uses a black powder, a person with compund bow, or someone with a recurve? The answer is no one is superior. It is how you chose to do it.

I urge all of you to go to the study and read it and learn what you can. It is at

http://files.dnr.state.mn.us/fisheries/muskie_pike/muskiepike_2020.pdf

It is an interesting read, and gives us all something to think about.

Thanks for your time.

[AWH]

 Originally Posted By: Bass N Spear

Every single person that spears, somewhere down the line, will spear a big fish. There is no doubt about it. Iv speared big fish as well. People have to understand that its going to happen. Its just like tip up fishing, its going to happen.

I don't believe that every person that spears will spear a big fish at some point. I know a number of people that simply do not spear with any intention of throwing the spear at anything over a few pounds. They spear for the sport and the enjoyment of watching the fish in their natural environment and will take a few 2 to 4 pounders for the table.

I'm not saying that this makes these people better. But let's not assume that all spearers will take a big fish at some point. To say this as a spearer is one reason why people against spearing will think that we are all bad for the size structure of pike in our waters. Personally, I have no use for a pike over 5 pounds. So I can guarantee that a spear will never leave my hand in the direction of anything bigger than that. I like the smaller fish for the table and I have no desire to put one on the wall. Simply a personal choice.

I realize that some people like the taste of big pike better. I will never understand that. But I will also never understand how some people like the taste of liver.

Food for thought...if (as spearers/anglers) we were to think of only what's best for our fisheries and not about our own "wants", would we still harvest fish in the same manner? Or would we choose a different approach to what we harvest?

Aaron

[Muskiefool]

It says that if you take the big fish out selectively the future generations of fish suffer what they call Maladaptive(Counterproductive or abnormal) Changes resulting in Low egg volumes, lower vertebral numbers, inability to feed under normal and pressured conditions, problems with stamina and strength, they grow slower, less fish hatch from eggs and survive.

Here are some of the things that jump out of the study this could be considered a blue print on how to create a Hammer Handle Lake, if you like large numbers of useless fish just kill the big ones its that simple, I'm not trying to P!$$ anyone off, I just think we all need to reevaluate our practices and learn that letting a big fish swim is the best for yourself and those kids you want to see grow up in a sport and pastime we can be proud of.

Populations where large fish were selectively harvested (as in most fisheries) displayed substantial declines in fecundity(reproduction), egg volume, larval size at hatch, larval viability(survival), larval growth rates, food consumption rate and conversion efficiency(the amount of food needed to grow), vertebral number, and willingness to forage. These genetically based changes in numerous traits generally reduce the capacity for population recovery.

It is unclear why some collapsed fisheries fail to recover even after harvesting has been reduced for more than a decade (Hutchings 2000; Hutchings & Reynolds 2004). By targeting the oldest, largest, and fastest growing individuals in a stock, fisheries generate strong directional selection favouring the survival of younger, smaller, and slower growing phenotypes(Quality of the fish and its genetics).

Larval growth rates were also 25% lower in comparison with randomly selected controls. Furthermore, the probability of survival of these larvae to an age of 10 days was 61% lower than survival in randomly harvested lines.

When subjected to a simulated predatory attack, large-size harvested fish remained in hiding for a significantly longer period of time before resuming foraging.

I hope this helped clear up some of the information it took me along time to figure out most of this stuff I'm just a fishermen myself.

[Hammer Handle]

I do spear big fish. I do let some go too. I have even taken and eaten muskies (some where in a lake that should NOT have any...they were illegally stocked).

If spear fishing was illegal, I would angle and keep large fish.

There has to be some give and take on both sides. Who is going to go out and keep all the small panfish and let the big ones go? How many catch and release fisherman will quit fishing in the dog days of summer for many of the fish they catch will not survive?

We have overfished our lakes for many years and we are trying to have them recover...but due to overfishing and lakeshore habitat being ruined...it will be next to impossible. But, we have to try...but there has to be give and take on both sides.

One guy argues to catch and release everything and then tears all the weeds out along his shore to make a beach for swimming and a spot for his $$ boat and lift. Another guy keeps all his fish to eat and catches much less for he only uses a small boat and 5 horse motor. It seems that the second example is being tarketed as more money lies with person #1 (taxes, $$ for boat and electronics, etc).

[shooter_mcgavin]

 Originally Posted By: Bass N Spear

There is nothing wrong with spearing big fish at all.

Nothing legally wrong with it. But would you agree that the big pike are important to the overall fishery of the lake? I believe removing them affects the quality of fishing for all species.

 Originally Posted By: Bass N Spear

Iv speared big fish as well. People have to understand that its going to happen. Its just like tip up fishing, its going to happen.

You make it sound like people don't have a choice "oh man, that's a big pike......wait, what's wrong with my arm......i can't control it...can't stop...don't wanna...aaaaaahhhhhhh....WAM!" Sorry had to have a little fun with ya this morning....

You can release northerns when you're tipup fishing. Yes there's a small mortality rate, but its not 100%. I'm curious, what do you do with a 15(+)lb pike that has holes in it? I'm assuming its ruined for mounting. Do they taste good? This is an honest question, I've wondered for a long time....

Bass n Spear, I see your point on the picture posted on the top of the thread. Makes sense that those pictures may not represent the average fish speared. However, if you browse through the walleye pictures thread, there's quite a few "eaters" in there. There's also some pigs, but the key is that a lot of them say C&R.

[merkman]

[shooter_mcgavin]

nice reply Merkman. can't say I've ever been called a troll before. I can take a hint, later dudes.

(thought it was a good discussion)

*edit* Let me just add, Merkman, that you've got 8 posts on this thread, the same as me! So I guess that makes you a troll as well....

You simply argued with my points (even proposing analogies for me to respond to), and when I respond, you label me a troll.....give me a break

[nine-tiner]

I am confused about the comments about the objection to the pictures in this forum of the large fish taken. Why are there no objections when the photos of all the trophy deer start showing up every fall?? I would love to shoot a trophy deer but it seems everyone else is shooting them before I get a chance...if the VERY FEW spearers out there can't post a picture without being "roasted" lets keep the "big buck" photos off as well because "trophy deer" might be "worth" even more

[fisherking01]

Please let me know what lakes you would not like me to spearfish and I will try to accomodate your wishes. Brent

[Scott M]

We have a thread that's kind of going in 15 different directions here. The thread title is "how important are our big pike", but we are getting into the ethics and ecology of spearing. We have referenced papers on atlantic silversides, a marine species (but I will say the point of the papers are to document classic symptoms of overexploitation, which is pertinent to the discussion of large pike scarcity and lakes stuck in hammerhandle mode). And we're reviewing the long range plan for pike and large muskies. Maybe it's all relevant to the discussion, maybe its not. But it sure it tough to sort through the discussion with so many topics presented.

I don't have much more to add other than to say it appears big pike are very valuable to our fisheries from a variety of standpoints (biological, ecological, economical, etc.)

As far as the merits and morality of spearing, to each their own. One (or a dozen) cannot speak for all the spearers in the state. All one can look at is the facts and let the opinions lay where they are.

I'm guessing no one will be able to get this paper without a subscription, but try reading at least the abstract of the following paper: "Recreational Darkhouse Spearing for Northern Pike in Minnesota: Historical Changes in Effort and Harvest and Comparisons with Angling" by Pierce and Cook (2000). A google search should bring the abstract up.

I'm not trying to kill this thread, just find a single track for it to move on. More posts on how valuable big pike are, are welcome.

[Tom7227]

I think the point is that there is a basis for concern no matter how a large pike or muskie is harvested. The aspersions cast by either side of the spear/no spear debate really don't add much other than to prove that some folks don't know how to spell, others are arrogant and many are ignorant about the consequences of their position/practices.

[shooter_mcgavin]

 Quote:

Please let me know what lakes you would not like me to spearfish and I will try to accomodate your wishes. Brent

Just to defend myself...I never suggested that I don't want people spearfishing. Obviously you may spear wherever you please. In fact, I mentioned that I wouldn't mind trying it sometime! The pictures of "norwegian tv" look pretty cool.

Again, I just think that over-harvesting large pike.....by any means.....affects a fishery (all species). Sorry that I singled out spear-fishermen.

Hope this isn't considered "trolling".... Just felt the need to go back to my original point, which is also the topic of this thread.

Thanks for posting the link to another discussion AWH.....its a good read but not the one I was thinking of. I looked a little but couldn't find it. It was an interesting perspective on the affects of over-harvesting big pike.

[fisherking01]

Sorry for the sarcasm, just too many directions for the title. Big pike are no doubt one of the decicisive factors to a healthy fishery that is indiginous to pike. Many fisheries that are managed (ie private lakes) for species without the presence of pike are extremely healthy and productive for the species they are managed for. Lakes with populations of pike are balanced with the pike on the top of the food chain. It is plain that these mighty predators will in certain cases keep the population of small pike, as well as smaller prey in check. It has been my observation that pike will in fact eat a diet of nearly entirely small pike given the opportunity. Sunfish, bass walleye, roughfish.... all are food for these predators. I don't know how much a healthy 20 pound pike has to eat to get to 25 pounds, but I beleive it is a lot. It's pretty much a given that if you find a lake with big pike, you'll find big sunnies. How valuable are big pike? all depends on the specific fishery. In a lake with only sunfish and walleyes, not much change, as the walleyes keep the sunfish in check. I some other lakes, Extremely valuable to the health of the fishery.

[browning_gold]

 Originally Posted By: shooter_mcgavin

You can release northerns when you're tipup fishing. Yes there's a small mortality rate, but its not 100%. I'm curious, what do you do with a 15(+)lb pike that has holes in it? I'm assuming its ruined for mounting. Do they taste good? This is an honest question, I've wondered for a long time....

Actually We have a couple trophy pike mounted that were speared and no there is no sign what so ever that it was speared.