Stella Posted November 10, 2009 Report Share Posted November 10, 2009 I did a trip on the weekend with a couple of friends to the Manawatu headwaters (inland from Norsewood) to find some dwarf galaxias - Galaxias divergens They are a teeny native, same family as the whitebait but they don't go to sea. They don't get much bigger than a large whitebait (circa 5cm). They live in fast flowing, bouldery headwaters, and have been decimated by trout. They look a bit like a koaro, and move like one, but have much smaller fins and a really blunt face, and seem to be upper-water drift-feeders. More info and a distribution map: http://www.niwa.co.nz/our-science/fresh ... f_galaxias I already have one in my riffle tank, but wanted to get him a few friends. To took a while to catch any, but now I have seven dwarfs in the quarantine tank! :lol: The photos are about as good as I can do at the moment given the state of the tank and how tiny and timid the fish are! Quote Link to comment Share on other sites More sharing options...
Caryl Posted November 10, 2009 Report Share Posted November 10, 2009 Nothing wrong with those pics Stella Quote Link to comment Share on other sites More sharing options...
livingart Posted November 10, 2009 Report Share Posted November 10, 2009 looking good stella can they be captive bred? Quote Link to comment Share on other sites More sharing options...
Stella Posted November 10, 2009 Author Report Share Posted November 10, 2009 Thanks It should be possible to breed them, not sure if anyone has. Very little is known (ie published) about these guys. Quote Link to comment Share on other sites More sharing options...
Insect Direct Posted November 10, 2009 Report Share Posted November 10, 2009 very cool Quote Link to comment Share on other sites More sharing options...
livingart Posted November 10, 2009 Report Share Posted November 10, 2009 there should be research on breeding them funded from trout licensing to repopulate areas they are preyeed on by the water weasels Quote Link to comment Share on other sites More sharing options...
Stella Posted November 10, 2009 Author Report Share Posted November 10, 2009 hehe indeed! Various bits of recent research on co-existence of certain non-diadromous galaxiids with trout tends to show that where there are distribution overlaps, there is a usually trout-free breeding population upstream that is supplying galaxiids to the trout/galaxiid area. Take away that population and the lower one dies out. Similarly in braided rivers there can be side-braids that are not suitable for trout, so the galaxiids hang out there. Abstract water for farming irrigation and the side-braids are lost and so are the galaxiids. I am looking forward to my dawrfs coming out of quarantine in a few weeks so I can put them in with my other dwarf - I want to see him all excited about getting some new friends! Quote Link to comment Share on other sites More sharing options...
Stella Posted November 11, 2009 Author Report Share Posted November 11, 2009 sigh, spoke to soon. I am almost embarrassed to say: they have now spawned in my tank.... I can see 3 spherical 2mm long eggs. The fish are all hiding and I suspect there may be more eggs under the rocks but I will leave them to it. Quote Link to comment Share on other sites More sharing options...
livingart Posted November 11, 2009 Report Share Posted November 11, 2009 will you be removing the adults? Quote Link to comment Share on other sites More sharing options...
Heir Posted November 11, 2009 Report Share Posted November 11, 2009 sigh, spoke to soon. I am almost embarrassed to say: they have now spawned in my tank.... I can see 3 spherical 2mm long eggs. The fish are all hiding and I suspect there may be more eggs under the rocks but I will leave them to it. OHHH that's so exciting! Quote Link to comment Share on other sites More sharing options...
Stella Posted November 11, 2009 Author Report Share Posted November 11, 2009 Well, the adults are in quarantine, and only days into it, which makes things awkward. I will see what I can find under the rocks later, and see if they are fertile. Of course no one knows if the adults are inclined to cause any damage.... Of course if the adults come down with anything I will have to remove the eggs if I want them to survive treating the adults. Quite what I would put them in I do not know! Actually, I know a scientist in the South Island who breeds different non-diadromous galaxias species, she may have some ideas, or have bred these guys before. Quote Link to comment Share on other sites More sharing options...
spoon Posted November 11, 2009 Report Share Posted November 11, 2009 my mate has a trout problem lol he has been a keen trout fisherman for 15 years but is now keeping south american cichlids and finding out about the damage trout are doing to the natives and mafs protection of them is doing to this hobby he now feels guilty going trout fishing i said go but dont put them back. now back on topic these dwarfs are they in the south island too? Quote Link to comment Share on other sites More sharing options...
Stella Posted November 11, 2009 Author Report Share Posted November 11, 2009 Trout are semi-ok. Yes they kill stuff (Lake Taupo used to be so thick with koaro the Maori would pick the off the beaches after strong winds, a few years after trout were introduced the population crashed). But without trout there would be a whole lot less interest in trying to clean up our rivers and streams. Unlike most other introduced species, trout like the water clean and cool, like the natives. In that sense they are an 'honorary native' for some biomonitoring purposes. They are also considered to be part of the ecosystem now, not ideal, but not going to have population explosions and wipe everything out,or change the habitat like possums. But yes, encourage him to catch as many as he likes Dwarfs are in the South Island, see map: http://www.niwa.co.nz/our-science/fresh ... f_galaxias Tis an odd distribution but quite a few plants and animals have a similar one. Relates to land moving and the cook strait being connected during the Pliestocene. Quote Link to comment Share on other sites More sharing options...
preacher Posted November 11, 2009 Report Share Posted November 11, 2009 Lol, I don't believe it! You have some new fish for what? 24? 48 hours and your breeding them already Stella! That is so cool! Did you know they were egg bearing when you caught them... Speaking of which, being Galaxiids shouldn't they spawn in Autumn like the Giant Kokopu you have? Or does this mean that the Kokopu has spawned at the proper time.... curious... Peter Quote Link to comment Share on other sites More sharing options...
Stella Posted November 11, 2009 Author Report Share Posted November 11, 2009 I suspect I had little to do with me and more to do with ripe little fishies suddenly finding themselves in close confines and making the most of it! Someone is thinking! Actually, no, these ones are spring spawners and the kokopu are autumn spawners. It relates to diadromy and where the food is. There is not a great deal of food for fry in streams apparently, but there is more over summer than winter. So those that are non-diadromous tend to spawn in spring. The diadromous kokopu spawn in autumn. There is a lot of food for a growing fish in the sea, then when they come back in spring as whitebait they find there is a lot of food in the freshwaters now. Just to completely screw up my theory, both diadromous and non-diadromous bullies spawn in spring. The only timing difference is that the non-d ones spawn in spring *and* summer. But one really interesting thing here is when the common bullies form landlocked populations. A study looked into the differences between the common bullies in a lake and those downstream from the lake in a river. Ones in the lake were non-d and the ones downstream were d. The non-d ones spawned in summer, because the lake would be too unproductive over winter to support fry. The fish downstream spawned over winter/spring. These were part of many factors (including genetics) that indicated that the two populations are diverging. This morning I can see six eggs. One looks milkier than the rest so maybe that one is not fertile. I will pull them out today and put them into another tank. Quote Link to comment Share on other sites More sharing options...
preacher Posted November 11, 2009 Report Share Posted November 11, 2009 Hmmm, I wonder if a population of diadromous Bullies got 'land locked' by an earthquake or something would alter their breeding habits according to the food level? It's amazing how some species exhibit behaviour that appears 'unlearned' Quote Link to comment Share on other sites More sharing options...
Stella Posted November 12, 2009 Author Report Share Posted November 12, 2009 Well, it all makes sense with evolution It is further for the upstream bullies to go to sea (even thought these catchments were fairly short), and the fry that hatched in the lake may not have caught the right currents to go to sea and so remained in the lake. Those that found enough food survived, most probably didn't. Over time, more of the fish that spawned in late winter or early spring would have had surviving offspring, and the would have developed a higher incidence of the 'spawn near spring' genes. Over more time some fish start spawning *in* spring, and their fry survive much better. Then later fish wind up spawning in summer, and their fry just rock with the food supply, so their genes take over. Lo and behold! Directional evolution leads to summer spawning lake bullies. And because they spawn at a totally different time, they can no longer spawn with the diadromous fish. Because they can't interbreed, new mutations in either population stay in that population, so they become genetically different. Wheee! Evolution! As the line goes: "nothing in biology makes sense except in the light of evolution" There are other instances of 'landlocked' fish that used to be diadromous. A study of river-living giant kokopu showed that some had never been to sea, despite having the opportunity. Though landlocking is difficult for some species, and impossible for others, hence the general lack of native fish above hydroelectric dams. Quote Link to comment Share on other sites More sharing options...
repto Posted November 12, 2009 Report Share Posted November 12, 2009 rainbow trout comes in at number 63 on this the list for the top 100 most invasive species?? Quote Link to comment Share on other sites More sharing options...
Stella Posted November 12, 2009 Author Report Share Posted November 12, 2009 ooh, Repto what is the link? Quote Link to comment Share on other sites More sharing options...
repto Posted November 12, 2009 Report Share Posted November 12, 2009 www.issg.org/database/species/search.asp?st=100ss try this or just google 100 most invasive species. Quote Link to comment Share on other sites More sharing options...
turtlemantaken Posted November 13, 2009 Report Share Posted November 13, 2009 and if you look look at link, check out number 83 which is also Rainbow Trout? Repto, came as a bit of a surprise but my trout spawned successfully in stillwater pond, wasn't expecting that. Quote Link to comment Share on other sites More sharing options...
repto Posted November 13, 2009 Report Share Posted November 13, 2009 you could start a catch your own fish resort......if you were not doing a runner??? Quote Link to comment Share on other sites More sharing options...
turtlemantaken Posted November 13, 2009 Report Share Posted November 13, 2009 Thought has crossed my mind repto ...........also many ducks visit, but of course there are laws against financial gain from these things. "Runner" is up in air at moment but I'm now without turtles or Blues so may need name change. Quote Link to comment Share on other sites More sharing options...
Benjansss Posted March 29, 2015 Report Share Posted March 29, 2015 Sorry to reopen this but did they hatch Quote Link to comment Share on other sites More sharing options...
Stella Posted March 29, 2015 Author Report Share Posted March 29, 2015 Nope, they didn't hatch. They were fertile and started developing, but slowly died off. I suspect water quality as they were a rather new and small emergency tank, but it was a long time ago. Quote Link to comment Share on other sites More sharing options...
(Medium).thumb.jpg.a01a77a9b0ed5d19a29af66986bf7df8.jpg)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.