Likes Likes:  0
Thanks Thanks:  0
HaHa HaHa:  0
Results 1 to 2 of 2

Thread: Catch & Release Big Mama

  1. #1
    Chicagobullshoals Guest

    Default Catch & Release Big Mama


    At lease a few of them because her babies have a better chance at survival.

    "New research suggests reeling in the big fish of long ago might have seriously impacted rockfish populations of today. Marine biologist Steven Berkeley, and a team of colleagues from the University of California Santa Cruz and Oregon State University, studied black rockfish---or Sebastes melanops---and reported in the journal Ecology that larvae, or baby fish, from older female rockfish grew faster and survived longer without food than the fish that came from young mothers, suggesting that hooking older, bigger fish could in the long run leave us with fewer fish to fry.

    Our whole theory of fishing may not be providing [the fish] with enough protection to enable them to survive and reproduce and maintain their population over the long-term, Berkeley warns.

    The team spent two years collecting pregnant female black rockfish that they transferred to holding tanks at the Hatfield Marine Science Center at Oregon State University. Just before the fish were expected to give birth, the researchers anesthetized them, removed their larvae and divided the larvae into three groups. One group got no food. The second group was fed a diet of tiny multi-cellular animals called rotifers at a concentration of 1 per mL of tank water, and the third group ate the same diet, but at a concentration of 10 per mL. As the larvae grew, Berkeley and his colleagues determined the ages of their mothers by counting the rings in each fishs otilus, or ear bone, just as you would a tree. "What we found was that the larvae from old fish grew more than three times faster than the larvae of young fish," he says. "The larvae of old fish could survive a period of starvation more than twice as long as the larvae of young fish."

    Their survivability, Berkeley believes, is linked to inherited oil globules. When rockfish are born, the only source of food that they contain is in the form of a little droplet of oil, explains Berkeley. Andthe oil droplet in the larvae from the old fish was much bigger than it was in the larvae of the young fish. The droplet---an opaque sphere located in the belly---feeds baby fish until they are big enough to swim against ocean currents and catch their own food. Older fish are able to give their young a bigger droplet is because they're not spending so much energy growing, Berkeley believes. Once you reach your maximum sizeyou have more energy to invest in your larvae, he says.

    Fish globule
    The droplets are at work in other fish like striped bass, salmon, and Atlantic cod, so if fish need this oil to survive, as Berkeley's work suggests, then it's imperative to protect older fish, just as we protect younger fish. Berkekely says establishing regulations that set an upper limit, not just a lower limit on the size of fish that can be caught, would do the trick.

    But boosting rockfish populations is complicated. Because they live in a diversity of habitats, theres no one regulation that can shield all them. Couple that with their slow growth---it takes females ten years to reach sexual maturity before they give to birth live young, not eggs---and baby rockfish either become food for bigger fish, are swept into unfriendly waters, or just starve. Berkeley says fishery management needs to be tailored to each species' life cycle, sexual maturity, larval mortality rate and habitat vulnerability. "

    For the whole story read this,

    http://www.sciencentral.com/articles...e_id=218392508

  2. #2
    Join Date
    Mar 2005
    Location
    Fayette, Al.
    Posts
    684
    Post Thanks / Like

    Default

    Quote Originally Posted by Chicagobullshoals
    At lease a few of them because her babies have a better chance at survival.

    "New research suggests reeling in the big fish of long ago might have seriously impacted rockfish populations of today. Marine biologist Steven Berkeley, and a team of colleagues from the University of California Santa Cruz and Oregon State University, studied black rockfish---or Sebastes melanops---and reported in the journal Ecology that larvae, or baby fish, from older female rockfish grew faster and survived longer without food than the fish that came from young mothers, suggesting that hooking older, bigger fish could in the long run leave us with fewer fish to fry.

    Our whole theory of fishing may not be providing [the fish] with enough protection to enable them to survive and reproduce and maintain their population over the long-term, Berkeley warns.

    The team spent two years collecting pregnant female black rockfish that they transferred to holding tanks at the Hatfield Marine Science Center at Oregon State University. Just before the fish were expected to give birth, the researchers anesthetized them, removed their larvae and divided the larvae into three groups. One group got no food. The second group was fed a diet of tiny multi-cellular animals called rotifers at a concentration of 1 per mL of tank water, and the third group ate the same diet, but at a concentration of 10 per mL. As the larvae grew, Berkeley and his colleagues determined the ages of their mothers by counting the rings in each fishs otilus, or ear bone, just as you would a tree. "What we found was that the larvae from old fish grew more than three times faster than the larvae of young fish," he says. "The larvae of old fish could survive a period of starvation more than twice as long as the larvae of young fish."

    Their survivability, Berkeley believes, is linked to inherited oil globules. When rockfish are born, the only source of food that they contain is in the form of a little droplet of oil, explains Berkeley. Andthe oil droplet in the larvae from the old fish was much bigger than it was in the larvae of the young fish. The droplet---an opaque sphere located in the belly---feeds baby fish until they are big enough to swim against ocean currents and catch their own food. Older fish are able to give their young a bigger droplet is because they're not spending so much energy growing, Berkeley believes. Once you reach your maximum sizeyou have more energy to invest in your larvae, he says.

    Fish globule
    The droplets are at work in other fish like striped bass, salmon, and Atlantic cod, so if fish need this oil to survive, as Berkeley's work suggests, then it's imperative to protect older fish, just as we protect younger fish. Berkekely says establishing regulations that set an upper limit, not just a lower limit on the size of fish that can be caught, would do the trick.

    But boosting rockfish populations is complicated. Because they live in a diversity of habitats, theres no one regulation that can shield all them. Couple that with their slow growth---it takes females ten years to reach sexual maturity before they give to birth live young, not eggs---and baby rockfish either become food for bigger fish, are swept into unfriendly waters, or just starve. Berkeley says fishery management needs to be tailored to each species' life cycle, sexual maturity, larval mortality rate and habitat vulnerability. "

    For the whole story read this,

    http://www.sciencentral.com/articles...e_id=218392508
    (Chicago);;; I agree, that sounds about right that the bigger fish have more nutrient's on which to feed there larvae. kind of a gene line. the healthier the female is the better her offspring will surive and grow like her. There's just one small problem with the next to the last statment( upper limit ). I anit throw-in my slabs back.Believe me I hate it when I cut into a female a see a sack of eggs as big as my fist come out. but i think the lower limit should actually be raised to 10" Ive fished holes out til i started catching 9"ers only to watch some guy come along after I've moved on up the banks, and start chuncking them in the live well, I know good in well what he was catching.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

BACK TO TOP