obesity

[chubb man]

they say the biggest killer in humans will soon be obesity.so what about fish for years now we've been throwing high protien baits at them. fish are getting bigger but whats it doing to there health.and now its salt they say to much salt is bad for you.what about the fish.if salt starts to be used like boilies & pellets. i think we should start looking to use more natural baits otherwise i think we could end up with a lot of fish dying of obesity and heart disease.

[Ron The Hat Clay]

Originally Posted by chubb man

they say the biggest killer in humans will soon be obesity.so what about fish for years now we've been throwing high protien baits at them. fish are getting bigger but whats it doing to there health.and now its salt they say to much salt is bad for you.what about the fish.if salt starts to be used like boilies & pellets. i think we should start looking to use more natural baits otherwise i think we could end up with a lot of fish dying of obesity and heart disease.

As regards salt, well some fish thrive in salty water, including several freshwater species.

It's easy to tell whether a fish is genuinely obese, or has lots of muscle. Feel it - a well built, deep, muscular fish is easy to recognize. A fat gutted monstrosity is also easy to point out.

As regards "high protein baits", some of them are good for fish, others are downright awful.

[Titus]

Fish live in water, they are weightless in their own environment, they are not effected by bulk, they might suffer liver damage from a high fat diet but it won't have any effect on their circulatory system. The golden orfe in my pond lived well beyond the suggested age range for the species despite being of specimen size, I think they'll be fine.

[markg]

Fish swim around a lot, humans just sit and watch TV. When they invent TV for fish then there could be a problem. they probably have in America.

[Eric Edwards]

Well it certainly happens in pike. Trout water pike grow very fat and very fast and as a result they live only around half as long as wild fish living in deep, cold water.

[Alan Tyler]

But how long compared to pike in similary shallow and warm lakes to their trout-lakes?
Cold-water animals are notorious for living longer than warm.

[Eric Edwards]

Trout water fish struggle to reach ten years in age, fish in similar lowland waters where there is just an average supply of food seem to reach between fifteen and eighteen years.
There's been some work done on this and you're right, pike age is directly proportional to latitude but also life expectancy is inveresely proportional to growth rate. (Miller and Kennedy)
The maximum age a pike can reach is 30 years, the oldest fish ever recorded being just a few months short of this.

[Alan Tyler]

Almost as if there were a pre-set maximum weight...
Some plants, incidentally, play the same sort of trick as cold/deepwater fish: they cope with limited growth due to overshading, nutrient deficiency or drought by having a very low growth rate necessary to stay alive - but put them in the light, water and feed them and they grow much faster, though still (iirc - it was a long time ago) not as fast as the competitors whose dominance they've adapted to circumvent.

Is this longevity study based on monitoring individuals, or otolith/scale readings, for the latter might miss any time spent maintaining good health without actually growing, mightn't it?

I googled Kennedy and Miller + Pike, and top of the search was this:Pike: Biology and Exploitation - John F. Craig - Google Books
which paints a more complicated picture, with exploitation and age at maturation emerging as big factors. Exploitation, in this paper, seems to mean removal of trophy fish; in the UK, with predation of smaller pike unnaturally high due to cormorants etc, it might exert the reverse pressure.
All fascinating, and bafflingly complex. And, I'm relieved to find, twenty years later than my last attendance at a freshwater biology lecture, which saves me a blush or two!

[Eric Edwards]

The book you refer to is an excellent work, very valuable for the pike angler as it goes into great depth about pike's habits. I had a copy for a while but had to give it back - too expensive to buy at £160. Couldn't say how the age was determined I'm afraid.
As you say, it's as if there's a predetermined maximum, although the book also states that Asian pike are much longer lived and reach a higher maximum size than either European or American pike do.

[noknot]

Originally Posted by Ron The Hat Clay

As regards salt, well some fish thrive in salty water, including several freshwater species.

It's easy to tell whether a fish is genuinely obese, or has lots of muscle. Feel it - a well built, deep, muscular fish is easy to recognize. A fat gutted monstrosity is also easy to point out.

As regards "high protein baits", some of them are good for fish, others are downright awful.

Please elaborate ron?