Tilapia?
On Thu, 31 Mar 2011 11:02:25 -0400, "Dora" > wrote:
>I love orange roughy but don't buy it, even though it has recently
>been removed from the endangered list. The fish takes an amazing 50
>years to breed, so I'll do my tiny part to let the species recover.
>I've expounded long and hard before about the overfishing which has
>decimated the industry, which
>I see even in my own State.
>Additionally, the factory boats, plus the demand, have wreaked havoc
>and I can't see a rebound in the foreseeable future.
The breeding seems to be anywhere between 20 and 40 years, depending
on the location and conditions.
Here's a bit more information about the Orange Roughy species:
"Orange roughy are oceanodromous, non-guarding pelagic spawners: that
is, they migrate several hundred kilometers between localized spawning
and feeding areas each year and form large spawning aggregations
(possibly segregated according to sex) wherein the fish release large,
spherical eggs 2.25 millimetres (0.089 in) in diameter, made buoyant
by an orange-red oil globule) and sperm en masse directly into the
water. The fertilized eggs which are said to be 2.0 to 2.5 mm, (and
later larvae) are planktonic, rising to around 200 meters (656 ft) to
develop, with the young fish eventually descending to deeper waters as
they mature.
Orange Roughy are also synchronous, shedding sperm and eggs at the
same time. The time between fertilization and hatching is thought to
be 10 to 20 days; fecundity is low, with each female producing only
22,000 eggs per kilogram of body weight which is less than 10 per cent
of the average for other species of fish. Also, spawning can last up
to 2-3 weeks and starts around June or July. Orange roughy are very
slow-growing, reaching maturity at 20-40 years of age.
The maturation age used in stock assessments ranges from 23–40 years,
which limits population growth/recovery, because each new generation
takes so long to start spawning.
LifespanThe maximum published age of 149 years was determined via
radiometric dating of trace isotopes found in an orange roughy's
otolith ("ear bone"). Similarly, counting by the growth rings of
orange roughy otoliths has given a maximum age of 125 to 156 years.The
validity of these results is questioned by commercial fishers as some
state the former method is controversial and the latter method is
known to underestimate age in older specimens. The issue has yet to be
resolved definitively but carries important implications relating to
the orange roughy's conservation status."
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