Keeping bigger fish can create giant fish???

[Hammer Handle]

This article says that fish can grow faster if smaller fish are kept, but keeping only the "big fish" can cause some to grow into giants.

I think the article says that we don't know anything yet....

http://www.msnbc.msn.com/id/20037483/

[polarsusd81]

Reading the story, it says the data was produced by a computer model. I am thinking that I will trust what is proven to be by the biologists that deal with the ecosystems on a daily basis versus a machine that will not function in water up to its knees. It sounds like a talk story with results that had to be published to get paid for doing a study.

[Questor]

It sounds plausible until you start to factor in fishing pressure. The big ones are usually the most vulnerable, so they don't last long when fishing pressure is applied.

[chrisduc]

Very interesting thought. I have to believe each system is different and a lot of different factors will effect the outcome. Definately something to consider.

[Fishin Beast]

Bigger panfish do eat different things than smaller panfish so there is one point. But you will kill the genes in the fish. What happens when those few trophys die? The young of the trophy fish will automatically become stunted as there are only small fish left. What you do is just control the overall population. That happens by having big predatory fish in the lake. They will weed out the weeker fish and keep only the strongest panfish.

[slipperybob]

Umm cannibals...giant fish eats big fish, big fish eats little fish.

Take big fish out of equation

Giant fish eats what? little fish...Ecosystem change/crash....

[nofishfisherman]

The logic just seems very flawed.

If you catch and keep the big fish what will be left to grow into giant fish?

There might be one or two elusive big fish that people couldn't catch which will probably grow into giants but they got that way becuase they couldn't be caught so from a fishermans perspective why would I want to manage a lake so that it maintains a very small population of giant fish that no one is able to catch?

I think the accepted method of releasing the bigger fish is working just fine and will continue to keep working.

[castmaster]

I think whats best is a balanced population of fish in all year classes and sizes.

[Hotspotter]

Most likely, there's a reason that the research in question was not published in a well-respected, peer-reviewed fisheries science journal. Rather, it was published in a very broad-brush journal with a less notable track record than many of the more mainstream fisheries biology publications.

Along with questions regarding modeling vs. sampling real populations, some of the major concerns I have are:

1. Interactive effects amongst different game species - i.e. predator/prey relationships - Cannibalistic or not

2. Assumption that fishing pressure, size structure, and environmental variables hold constant

3. Long-term sustainability of this approach

It seems to me that this flies in the face of years of fisheries research regarding selective harvest, fishing opportunity, and pressure. In other words, it's far too soon to suggest that harvesting large fish help what's left become giant; especially when based on an untested artificial sample.

Joel

[Dave B]

I dont think that they are saying that the overall fishery will have big fish, but that there will be a handful of fish that will be much larger than what is in a typical lake.

I saw an example of this growing up in Eden Prairie. We caught a ton of very small fish from Round Lake (which is about 30 acres, just under one mile around). They killed it off 2-3 times and there would be HUGE fish in there each time it was killed off. We would also stumble into schools of 1lb+ sunnies where the rest were tiny. It was extremely rare to catch a "regular" size fish, they were huge or stunted.

[Muskiefool]

Computer generated Mother Nature Heres a abstract of a study that shows how that theoretical computerized management system fails

Source: Blackwell Synergy

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.

[papabear]

It is intersting to try and theories fish size managemnet. We can guess and dream that wecan do things to produce trophies for us to catch. But genetics, lake classification, weather, overall fish population, development, and fishing pressure all have an effect on the lakes. We have lakes that will never grow trophies and lakes that consistently do. I wonder more of why must we produce trophies to catch. If that is your sole purpose of fishing you may be missing the boat. And we wonder why we are not recruiting as many young fishermen/girls.