[One of Theo's Long-Haired Threads]
All our different breeds of dog come from common, non-specialized ancestors - mostly, from what I understand, a small sub-species of wolf common to semi-desert Eurasia. Yet dogs have been bred into a myriad of behaviors and forms - Poodles and St. Bernards, Yorkies and Irish Wolfhounds, Beagles and Afghans, Greyhounds and Dachshunds. Even though they come in vastly different sizes, patterns, and behaviors, they're all still the same species and (genetically, they ARE some physical differences that complicate certain cross-breedings) they can all produce viable offspring together.
Are we approaching a similar differentiation with our common species of sportfish? Just as East Asians have done for centuries with Koi, are we on the verge of producing distinct breeds of bream, bass, etc. to fit different purposes?
Condello has been busy for several years turning BG into pellet feeding frenzied Mastiffs, some LMB breeds selected for aggressiveness and pellet feeding seem to be being developed and pushed commercially, and I for one would love to see that Camo bass posted here earlier in the week available as a breed of peacock bass look-a-likes for the temperate zone.
What do you think of breeding the species of fish we know best into specialize variants? How could we keep track of them truly being what they are supposed to be, if their appearance as fingerlings is not distinct? What breeds of which species of fish do you see a use for?
Off the top of my head, the optimum CSBG (hungry, aggressively eating, fast growing, late maturing) seems at odds (in at least some respects) with the kind of BG that would make the best forage for a big bass pond. So there are two possible variants of one species of fish to start the discussion with.
Thoughts?
I'm trying a change of venue to see if anyone is interested in engaging in some sheer speculation. See how it plays with Dave in Peoria.
My thoughts are that CSBG will eventually evolve a preference for eating FH minnows and YOY BG over invertabrates and pellets. Their "agressiveness" might make them easy easy targets for LMB when they are still snack size for LMB.
Least we miss the forest for the trees. In the broad sense there is no difference in what Theo describes and the evolution of Centrarchidae from the chart above. For every successful branch there were probably 100,000 maybe a million unsuccessful non-viable attempts. Each one takes a long , long time. Conceptually there is little difference (except speed of change) in mother nature making a change and man. From the fish's view either way they are subject to the pressure of change no matter if the source is man or nature.
Eric, is that your March Madness bracket?
Theo, it seems to me that selective breeding of fish would produce results dozens of times faster than dogs. I don't get why BG and crappie haven't been bred up long ago. Seems to me that (fruitflies aside!) not many creatures would be a better candidate for selective breeding. Consistent 2 pound BG would be wonderful for pond fishing. Fast growing 3 pound crappie could be a successful agricultural fish for the table.
Maybe I'm wrong. Maybe most fish don't have enough genetic diversity to rapidly breed up bigger or faster growing strains.
Maybe there are many hobbyists out there (much like Bruce) that already have improved strains; and (unlike Bruce) are not Internet users.
Bobad, I don't know if fish could be selectively bred faster than dogs - one would have to consider the age from birth to being able to reproduce, after showing presence of the traits that the breeder wished to reinforce. My guess is that the two selection rates are roughly equivalent, though.
IIRC Bruce has talked about or at least presented some of the barriers that I think have prevented traditional fish hatcheries from doing significant selection. To truly know which BG are reproducing in his ponds, he has a lot of labor intensive work to drain out the ponds and separate out the next generation of parents.
Then what happens if a highly selected strain is available for sale, gift, or trade? Careless introduction into an existing population 1) exposes those genes to lurkers and cuckholders and 2) likely lacks the small ponds and labor intensive effort needed to maintain the strain in the face of a non-selected popoulation. Kind of like letting your $2,000 pure bred female dog run every night with the neighborhood mongrels - the pups would likely leave a lot to be desired from an AKC viewpoint.
A pond full of fish is a more difficult place to make purebreeds than a kennel, IMHO. Developing and maintaining either fish or dog breeds requires having the breeding be more controlled than what exists in the average fish pond. If you let the breeders take charge of all reproduction, it's much easier to control the offspring. Most ponds and most pond owners don't work that way, I think a higher % of dog owners do.
dogs and roses are easy to manipulate and i think thats just it theo....it'd all be about control. achievable by sectioned breeding ponds? maybe gw can think about this w/ his FH/RES pond.
Here is some long-haired info about what you seek.
TEMPO OF HYBRID INVIABILITY IN CENTRARCHID FISHES
(TELEOSTEI: CENTRARCHIDAE)
DANIEL I. BOLNICK AND THOMAS J. NEAR
We found that hybrid embryo viability declined at mean rate of 3.13% per
million years, slower than in most other taxa investigated to date.
Due to its gradual nature, the process of speciation usually
cannot be followed from inception to completion in a researcher’s
lifetime. To circumvent this limitation, studies of
speciation often take a comparative, cross-sectional approach.
Rather than follow the branching of a single lineage
through time, one can survey a number of species pairs that
have progressed different distances along the path toward
speciation. Assuming that the different pairs follow similar
evolutionary trajectories caused by similar mechanisms, one
can obtain general observations about the tempo and mode
of speciation.
Using a Kendall-Moran estimate of the net diversification
rate based on a pure birth process (Baldwin and
Sanderson 1998; Nee 2001), we found that the mean net
diversification rate in centrarchids is 0.090 species per lineage
per million years (95% CI: 0.066, 0.128), or an expected
waiting time of 11.15 million years for a lineage to speciate
into surviving descendents (95% CI: 7.76, 15.24).
The long lag phase and slow decline in viability suggest
that centrarchids evolve postzygotic isolation more slowly
than many other taxa investigated to date. No other studies
have measured the incompatibility clock in a comparable
manner (percent loss of viability per million years). However,
we can use several benchmarks as a basis for comparisons
between groups. Setting aside questions about their clock
calibrations, previous studies claim that the minimum age for
total hybrid inviability is 1.5 million years in anurans (Sasa
et al. 1998), 2 million years in Drosophila (Coyne and Orr
1997), 4 million years in Lepidoptera (Presgraves 2002), and
5.5 million years in birds (Price and Bouvier 2002; Lijtmaer
et al. 2003). In contrast, the minimum age for total inviability
in centrarchids is 24.81 million years (node 3, Fig. 2), though
this is only for one direction of a reciprocal cross.
Appendix).
Centrarchids also retain nonzero viability and heterosis
for much longer than most other taxa.
We propose two possible explanations for why centrarchids
evolve genetic incompatibilities more slowly than other
taxa. First, the comparisons discussed above ignore the effect
of generation time. With generation times of two to four
years, it is not surprising that isolation would take longer for
centrarchids than for Drosophila. However, this explanation
is not completely satisfying, as centrarchids are also slower
than the equally long-lived birds, mammals, and anurans. A
more likely explanation is that Haldane’s rule, an important
mechanism of postzygotic isolation, may be weak or absent
in centrarchids. Theory suggests that hybrid fertility and inviability
should evolve more quickly in taxa with larger X
chromosomes and slower in taxa with smaller ones (Orr and
Turelli 2001). This is because the size of the sex-specific
chromosomal region determines the number of hemizygous
recessive alleles that can interact with dominant autosomal
loci to produce hybrid dysfunction (Turelli and Begun 1997).
