Well I saw this article on Yahoo and just couldn't resist. I don't know about thowing back all the big fish but maybe a few from every days catch.<br /> 
<br />Study: Throw Back the Big Fish <br />Thu Jul 4, 2:14 PM ET <br />By PAUL RECER, AP Science Writer <br /><br />WASHINGTON (AP) - Most fishermen like to catch and keep the big ones and throw the little guys back, but a new study suggests that it's better for the fish species to do exactly the opposite.<br /><br /> <br />In a study in the journal Science, researchers at the Stony Brook University in New York conducted a four-generation laboratory study of fish and found that when the bigger fish are allowed to live, eventually the species may double in size and number.<br /><br />The study, led by David O. Conover, a professor at the Marine Sciences Research Center at Stony Brook, experimented with a species called the Atlantic silverside, a small fish that lives, reproduces and dies within a single year. The silverside is commonly used as bait by sports fishermen in the Northeast.<br /><br />Conover said the experiment started with 1,000 fish in each of three groups. In one group, the scientist harvested the 900 largest fish. In a second group, they took the 900 smallest fish, and in the third group the fish were harvested randomly in size. Then all three groups were allowed to reproduce and the cycle started all over again.<br /><br />In the first year, the largest-harvested group produced the most weight or biomass, while the smallest-harvested group produced the least.<br /><br />But after that, the biomass production roles reversed. Conover said that in each succeeding generation, the group from which the smallest 90 percent were harvested began to produce more and bigger fish than the other groups. The randomly harvested group did not change in size.<br /><br />"In the small-harvested group, the average survivor evolves to a bigger size and their reproductive output is twice that of the survivors in the large-harvested group," said Conover.<br /><br />The scientist said the experiment shows that a management plan that limits the catch to only the bigger fish a common practice for many sports species is actually harming the fishery in the long run.<br /><br />The reason, said Conover, is "evolutionary dynamics" the effect of genetic selection.<br /><br />He said that when only the big fish are harvested, it leaves behind the smallest to reproduce. Over time, this tends to make the survival genetics favor small size and the species actually get smaller in succeeding generations.<br /><br />However, when only the smaller fish are harvested, then the survivors are bigger and tend to produce offspring that are also bigger.<br /><br />After four generations of the experiment, average weight of spawning fish in the large-harvested group was 1.05 grams (.03 ounces), while the average size of the spawners in the small-harvested line was 6.47 grams (.22 ounces).<br /><br />Conover said this principal should apply to most free-swimming harvested fish.<br /><br />Another fish expert, however, said the Conover experiment is too limited to suggest changes in fish species management practices.<br /><br />"All they have done is show that growth rates are heritable," Ray Hilborn of the University of Washington, Seattle, said in statement to Science. "What they haven't done is see what the impact of this would be on a realistic fishery."
<br />Study: Throw Back the Big Fish <br />Thu Jul 4, 2:14 PM ET <br />By PAUL RECER, AP Science Writer <br /><br />WASHINGTON (AP) - Most fishermen like to catch and keep the big ones and throw the little guys back, but a new study suggests that it's better for the fish species to do exactly the opposite.<br /><br /> <br />In a study in the journal Science, researchers at the Stony Brook University in New York conducted a four-generation laboratory study of fish and found that when the bigger fish are allowed to live, eventually the species may double in size and number.<br /><br />The study, led by David O. Conover, a professor at the Marine Sciences Research Center at Stony Brook, experimented with a species called the Atlantic silverside, a small fish that lives, reproduces and dies within a single year. The silverside is commonly used as bait by sports fishermen in the Northeast.<br /><br />Conover said the experiment started with 1,000 fish in each of three groups. In one group, the scientist harvested the 900 largest fish. In a second group, they took the 900 smallest fish, and in the third group the fish were harvested randomly in size. Then all three groups were allowed to reproduce and the cycle started all over again.<br /><br />In the first year, the largest-harvested group produced the most weight or biomass, while the smallest-harvested group produced the least.<br /><br />But after that, the biomass production roles reversed. Conover said that in each succeeding generation, the group from which the smallest 90 percent were harvested began to produce more and bigger fish than the other groups. The randomly harvested group did not change in size.<br /><br />"In the small-harvested group, the average survivor evolves to a bigger size and their reproductive output is twice that of the survivors in the large-harvested group," said Conover.<br /><br />The scientist said the experiment shows that a management plan that limits the catch to only the bigger fish a common practice for many sports species is actually harming the fishery in the long run.<br /><br />The reason, said Conover, is "evolutionary dynamics" the effect of genetic selection.<br /><br />He said that when only the big fish are harvested, it leaves behind the smallest to reproduce. Over time, this tends to make the survival genetics favor small size and the species actually get smaller in succeeding generations.<br /><br />However, when only the smaller fish are harvested, then the survivors are bigger and tend to produce offspring that are also bigger.<br /><br />After four generations of the experiment, average weight of spawning fish in the large-harvested group was 1.05 grams (.03 ounces), while the average size of the spawners in the small-harvested line was 6.47 grams (.22 ounces).<br /><br />Conover said this principal should apply to most free-swimming harvested fish.<br /><br />Another fish expert, however, said the Conover experiment is too limited to suggest changes in fish species management practices.<br /><br />"All they have done is show that growth rates are heritable," Ray Hilborn of the University of Washington, Seattle, said in statement to Science. "What they haven't done is see what the impact of this would be on a realistic fishery."
