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

[MAKAI]

When "WE" are done with the way we handle the oceans.
Not just over fishing, we will all have a jellyfish sea to enjoy.
Seems jellyfish just love what we do. Google it and look around.

[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.

[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.

[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!

[Striper_Haven_03]

Originally Posted by numbskull

Too many people gain too much by killing large fish for anything to change while there are still large fish to be killed.

It has gotten to the point where killing them just to spite others is half the fun.

Couldnt agree more.