Came across this in my daily Science Daily reading- keeping big fish

[Mr. Sandman]

There are conflicting views on this matter. On the surface it appears that big fish will produce more...well in general that is true but as a fish moves beyond its peak fecundity age its eggs are not as ripe as a younger fish. Most other species have trouble reproducing when they get old. (A 19 year old hottie vs a 75 year old grandma) I know fish reproduce through-out their life but if you have ever opened up a 20#er and a 50#er you will see the color of the eggs in the 50 are indeed different, some look dead. I am not a fish biologist but I would rather bet the biomass future of a species on three 20#ers than one 60#er. As I think 3 20's will produce more than 1 60 and also, If the 60 dies for any reason, you have nothing. If a single 20 dies, you still have 2 more. IMO More is better in this case.

Again I am no expert but I like the idea of protecting everything instead of a subset.

Lastly, Fishery guys have proven they don't know jack%$%$%$%$. If they did we would not have the problems we have now. They have been managing fisheries for decades without results.

[Nebe]

Originally Posted by Mr. Sandman

There are conflicting views on this matter. On the surface it appears that big fish will produce more...well in general that is true but as a fish moves beyond its peak fecundity age its eggs are not as ripe as a younger fish. Most other species have trouble reproducing when they get old. (A 19 year old hottie vs a 75 year old grandma) I know fish reproduce through-out their life but if you have ever opened up a 20#er and a 50#er you will see the color of the eggs in the 50 are indeed different, some look dead. I am not a fish biologist but I would rather bet the biomass future of a species on three 20#ers than one 60#er. As I think 3 20's will produce more than 1 60 and also, If the 60 dies for any reason, you have nothing. If a single 20 dies, you still have 2 more. IMO More is better in this case.

Again I am no expert but I like the idea of protecting everything instead of a subset.

Lastly, Fishery guys have proven they don't know jack%$%$%$%$. If they did we would not have the problems we have now. They have been managing fisheries for decades without results.

I think a more valid point is that if you remove the largest fish from the gene pool and release all the small fish, your removing any fish that may be genetically geared to grow big. While some of the the smaller fish may be wired to be small..

[Mr. Sandman]

Originally Posted by Nebe

I think a more valid point is that if you remove the largest fish from the gene pool and release all the small fish, your removing any fish that may be genetically geared to grow big. While some of the the smaller fish may be wired to be small..

That is utter nonsense! Does not work that way…all fish have the ability to grow based on the genes at birth (and the conditions they experience during life)

You are born with certain genetics, and they don't change with age.


That is kind of like saying, if we keep circumcising kids, eventually they will be born circumcised.

Taking big fish out of the population does not affect genetics.



Bronko, I think we need to be more conservative than that and save all of them, not just a selected class of fish. As I said, I think fishery experts have a terrible track record for getting it right, best to err on the side of conservation.
SB should be a Gamefish and cut all the management crap.

[Nebe]

Originally Posted by Mr. Sandman

That is utter nonsense! Does not work that way…all fish have the ability to grow based on the genes at birth (and the conditions they experience during life)

You are born with certain genetics, and they don't change with age.


That is kind of like saying, if we keep circumcising kids, eventually they will be born circumcised.

Taking big fish out of the population does not affect genetics.

I still disagree. have you seen a gigantic kid in high school who looks like he is a senior in college?? I am sure there are fish that grow like that too- and if you kill one of these fish when they are just maturing they will not be able to pass on those genes- however the runt bass who take a long time to grow may have many chances to spawn-

[Nebe]

to make this simpler- WHen you remove all of the healty desirable stocks, only the runts will thrive.

[tattoobob]

Originally Posted by Nebe

I still disagree. have you seen a gigantic kid in high school who looks like he is a senior in college??

That's called inbreeding

[MarkB]

This is basic population biology - there are libraries full of this stuff. The bigger fish are older, and have been tested through all the challenges life puts out, and have survived. They are the best of the best, and they are the fish you want breeding. Small, young fish consist of the good and the not so good. Each year weeds out the less fit, so each year's class of fish is more likely to be more fit than the year younger.

For striped bass, and many other fish, the biggest fish are all females, and females are more important than males (sorry guys), so there's extra reason to release them.

[zimmy]

Originally Posted by Mr. Sandman

[COLOR=black][FONT=Verdana]That is utter nonsense! Does not work that way…all fish have the ability to grow based on the genes at birth (and the conditions they experience during life)

Really not utter nonsense. If a fish is big, it has the genetics and behavior traits to get big. The more it reproduces, the more big fish there will potentially be. Targeting big fish selects for a population of smaller fish. Lots of evidence in nature for this.

[PaulS]

Originally Posted by zimmy

. If a fish is big, it has the genetics and behavior traits to get big. The more it reproduces, the more big fish there will potentially be. Targeting big fish selects for a population of smaller fish. Lots of evidence in nature for this.

The same thing has happened with the Amur Tiger (Russia) and the easter North American Moose. Hunters hunted the large and left the smaller. Its called trophy hunting. It doesn't mean that the offspring will ALL be small but a smaller parent will on average have smaller offspring than a large parent.

[JackK]

Originally Posted by Mr. Sandman

There are conflicting views on this matter. On the surface it appears that big fish will produce more...well in general that is true but as a fish moves beyond its peak fecundity age its eggs are not as ripe as a younger fish. Most other species have trouble reproducing when they get old. (A 19 year old hottie vs a 75 year old grandma) I know fish reproduce through-out their life but if you have ever opened up a 20#er and a 50#er you will see the color of the eggs in the 50 are indeed different, some look dead. I am not a fish biologist but I would rather bet the biomass future of a species on three 20#ers than one 60#er. As I think 3 20's will produce more than 1 60 and also, If the 60 dies for any reason, you have nothing. If a single 20 dies, you still have 2 more. IMO More is better in this case.

Again I am no expert but I like the idea of protecting everything instead of a subset.

Lastly, Fishery guys have proven they don't know jack%$%$%$%$. If they did we would not have the problems we have now. They have been managing fisheries for decades without results.

I've always wondered about this myself, and have done a little homework...

What you're talking about is called senescense- biological aging. It's a common theory used among fishermen to justify keeping large fish. One old cow is not as fertile as two younger females, and therefore it's better to have more 20-30 lb fish in the population, and OK to keep the large ones.

Unfortunately this is comparing fish to people- they aren't. There's surprisingly little research done on striped bass fecundity (the ability to reproduce), which is weird seeing as they're such a valuable and important fish. One study by Richards, Fogarty & Teichberg (Density-dependent Growth and Reproduction of Chesapeake Bay Striped Bass) found that as the total length and weight of striped bass increased, fecundity increased. Monteleone & Houde at UMD also did a study entitled Influence of maternal size on survival and growth of striped bass Morone saxatilis Walbaum eggs and larvae- they found that small females produced small larvae, while large females produce large ones. Additionally, the larvae from large females grew faster than those from the smaller ones. They did note that a significant difference in survival to 25 days post hatch was not noticed.

So what does that mean? Large fish produce more fertile and viable eggs than small fish, and large fish produce larger larvae that grow faster. In a laboratory setting, survival was not influenced by female size... However in the wild the larger you are when born and the faster you grow will have a direct effect on survival (less things can eat you).

So basically, while the research on striped bass is limited, the common understanding among icthyologists is that the larger the fish, the more valuable it is to the population and sustainablility. The growth is fairly linear- a 10kg fish is about half as fecund as a 20kg fish.

So, don't think that the old cows aren't providing as much to the population as the smaller ones- they're providing much more. However I wholly agree that protecting just a subset isn't the answer.

[bucko]

Awhile back I asked a fisheries biochemist I know if there was any thing like menopause in fish . He let me know that in his experience the age of the fish didn't impact the viability of the eggs. Old fish produce more eggs and they are just as healthy as eggs from younger fish.

[BassDawg]

Originally Posted by JackK

I've always wondered about this myself, and have done a little homework...

What you're talking about is called senescense- biological aging. It's a common theory used among fishermen to justify keeping large fish. One old cow is not as fertile as two younger females, and therefore it's better to have more 20-30 lb fish in the population, and OK to keep the large ones.

Unfortunately this is comparing fish to people- they aren't. There's surprisingly little research done on striped bass fecundity (the ability to reproduce), which is weird seeing as they're such a valuable and important fish. One study by Richards, Fogarty & Teichberg (Density-dependent Growth and Reproduction of Chesapeake Bay Striped Bass) found that as the total length and weight of striped bass increased, fecundity increased. Monteleone & Houde at UMD also did a study entitled Influence of maternal size on survival and growth of striped bass Morone saxatilis Walbaum eggs and larvae- they found that small females produced small larvae, while large females produce large ones. Additionally, the larvae from large females grew faster than those from the smaller ones. They did note that a significant difference in survival to 25 days post hatch was not noticed.

So what does that mean? Large fish produce more fertile and viable eggs than small fish, and large fish produce larger larvae that grow faster. In a laboratory setting, survival was not influenced by female size... However in the wild the larger you are when born and the faster you grow will have a direct effect on survival (less things can eat you).

So basically, while the research on striped bass is limited, the common understanding among icthyologists is that the larger the fish, the more valuable it is to the population and sustainablility. The growth is fairly linear- a 10kg fish is about half as fecund as a 20kg fish.

So, don't think that the old cows aren't providing as much to the population as the smaller ones- they're providing much more. However I wholly agree that protecting just a subset isn't the answer.

for me and my viewing dollars~~~

^^^THIS GUY^^^ makes the most sense! and he has the degrees and hours on the sea and in the labs to form his opinions from. as much as i like your vim and vigor, MakoMike, the biological science does support Eb's view.

[MakoMike]

Originally Posted by BassDawg

What you're talking about is called senescense- biological aging. It's a common theory used among fishermen to justify keeping large fish. One old cow is not as fertile as two younger females, and therefore it's better to have more 20-30 lb fish in the population, and OK to keep the large ones.

Unfortunately this is comparing fish to people- they aren't. There's surprisingly little research done on striped bass fecundity (the ability to reproduce), which is weird seeing as they're such a valuable and important fish. One study by Richards, Fogarty & Teichberg (Density-dependent Growth and Reproduction of Chesapeake Bay Striped Bass) found that as the total length and weight of striped bass increased, fecundity increased. Monteleone & Houde at UMD also did a study entitled Influence of maternal size on survival and growth of striped bass Morone saxatilis Walbaum eggs and larvae- they found that small females produced small larvae, while large females produce large ones. Additionally, the larvae from large females grew faster than those from the smaller ones. They did note that a significant difference in survival to 25 days post hatch was not noticed.

So what does that mean? Large fish produce more fertile and viable eggs than small fish, and large fish produce larger larvae that grow faster. In a laboratory setting, survival was not influenced by female size... However in the wild the larger you are when born and the faster you grow will have a direct effect on survival (less things can eat you).

Note how his conclusion is directly contradicted by the study he is citing?

[JackK]

Yep... In a lab, with no predators.

Not going to cherry pick data, I'll cite all of the findings, whether or not they support my conclusions. But it's common sense in biological terms. To make it overly simple: You have oviparous fish (let's say herring, cod, stripers) that often produce millions of eggs, with innumerable larvae... They get preyed upon, with the hope that one out of every million survives to maturity to breed again. Then you have the species that put a ton of energy and care into producing small amounts of large, healthy juveniles- generally ovoviviparous and viviparous, sharks & rays come to mind. The theory is that these larger juveniles have a better chance of survival as they're born larger.

So yes, in a controlled setting with no natural predation there was no difference in survival 25 days post hatch (DPH). But what about 50 DPH? 100? Study hasn't been done, so who knows? Striped bass don't metamorphose fully into juveniles until 33-35 DPH (Lal, Lasker and Kuljis, 1977), and I know from my own aquaculture days (albeit with different species) that that's when a high percentage of mortality can occur.

All I'm saying is that big fish make big babies that grow fast. There's no scientific record of a big fish being any less fertile than a smaller one... Which is what the original discussion was about. The graphs below show fecundity vs. weight. I'd rather have more of those big, fertile fish swimming around... in addition to those 20's and 30's that also pump out young.

One thing's for sure, it's surprising that such little research has been done on this subject.

[Mr. Sandman]

This is all very interesting and we can debate these nuances until the cows come home (pun intended) but IMO, due to the unknowns of nature we should just protect the entire species and stop pretending how smart we all are and say we can protect the species by saving a subset of the fish. Face it fishery management results have not been that great in recent decades.

What has worked is total protection...on the west coast 450 stripers were transplanted in 1880-something. They established themselves and eventually they had a commercial harvest of over a 1 million #, then, the population declined due to overfishing. It was then made a game fish and there are now plenty of bass...The West Coast range of the species is now from Los Angeles north to the Columbia River...all from 450 original fish.

This does not require a lot of expensive science..and it certainly does not require management decisions based on user groups and POLITICS!....all it requires is common sense.

Make it a game fish, allow 1 fish bag limit any size. Then go focus on its food supply.

[Nebe]

Originally Posted by Mr. Sandman

This is all very interesting and we can debate these nuances until the cows come home (pun intended) but IMO, due to the unknowns of nature we should just protect the entire species and stop pretending how smart we all are and say we can protect the species by saving a subset of the fish. Face it fishery management results have not been that great in recent decades.

What has worked is total protection...on the west coast 450 stripers were transplanted to 1880something. They established themselves and eventually they had a commercial harvest of over a 1million # then the population declined due to overfishing. It was then made a game fish and there are now plenty of bass...The West Coast range of the species is now from Los Angeles north to the Columbia River.

This does not require a lot of expensive science..and it certainly does not require management decisions based on user groups and POLITICS!....all it requires is common sense.

Make it a game fish, allow 1 fish bag limit any size. Then go focus on its food supply.

Yes!!
Posted from my iPhone/Mobile device

[JackK]

Originally Posted by Mr. Sandman

This is all very interesting and we can debate these nuances until the cows come home (pun intended) but IMO, due to the unknowns of nature we should just protect the entire species and stop pretending how smart we all are and say we can protect the species by saving a subset of the fish. Face it fishery management results have not been that great in recent decades.

What has worked is total protection...on the west coast 450 stripers were transplanted to 1880something. They established themselves and eventually they had a commercial harvest of over a 1million # then the population declined due to overfishing. It was then made a game fish and there are now plenty of bass...The West Coast range of the species is now from Los Angeles north to the Columbia River.

This does not require a lot of expensive science..and it certainly does not require management decisions based on user groups and POLITICS!....all it requires is common sense.

Make it a game fish, allow 1 fish bag limit any size. Then go focus on its food supply.

Amen x2!