Sorry for not communicating recently… life and all that… but tried to make quite a long post yesterday but it seems not to have saved. Life and all that… This is a fascinating thread and I have a few points that I hope will add spice:
1. ALIEN INTRODUCTIONS
In my opinion, as a scientist that’s worked on aquatic systems all over the world, a BAD idea!! I’ve worked on the aftermath of carp introductions in Australia, USA, Europe and Africa and it ain’t a pretty sight for the balance and stability of ecosystems. Ditto American crayfish in Africa and Europe, American mink in Europe, Nile Perch outside of their native African range, barbel in some British rivers where they did not occur previously, etc. Also zebra mussels, ruffe, New Zealand swamp stonewort, topmouth gudgeon, sunbleak, etc., etc…. I could go on. Introductions may seem attractive but the downsides for whole ecosystems are potentially vast and certainly too big to risk. For all the ‘successes’ (trout in Nepal, etc.) there is a far bigger dark shadow of failures.
2. CONSERVATION IN SITU
Sadly for the threatened mahseer, the only solution is protecting the rivers in which they occur. Now, mahseer are a lot like salmon in some regards, using whole river systems from headwaters for spawning and nursery areas through to lowland big stretches for summer survival and maximum growth. They need habitat, water quality, adequate flows, seasonality of river discharge, her factors besides to be right, prospering or suffering with whole river systems. Trouble is, development (industry, land use, dams) tends to operate at local river stretch, or at best State only, levels. We need to look broader to see how to protect, restore or mitigate the ‘pinch points’ on the whole system. They can persist in lakes, but they need access to good spawning habitat or these populations are not viable, so there are ways of maximising the opportunity without blocking off development… it is just that we have to look at catchment scale and seek the sustainable solution (not that Europe has any brilliant examples to share beyond the work of the voluntary sector in formation of River Trusts.) How to achieve that in India? That is for all of us who care to deduce.
3. TRUSTING TO TECHNOLOGY
I wish I had the faith to say that the mahseer will still be there when this round of development is complete, noting the previous poster’s point about British salmon. Sadly, British salmon are few and not well!! And as to the burbot, most shad populations, etc… I rather feel that this is nettle we have to grasp together rather than hoping for the best! Same applies to the ‘we’re part of nature so introductions are natural too’ line. We’re natural but that’s no excuse for bombing or machine-gunning cities, or hunting the dodo to extinction!
4. LOCAL SPECIES AND GENETIC STOCKS
The widespread stocking as a panacea worries me for four reasons. (1) It overlooks the importance of protecting or fixing the catchment so that mahseer populations can be self-sustaining. (2) Various species of mahseer are bred at Lonalva (and elsewhere) and it is possible that the ‘wrong’ species may be stocked. (3) Hybrids are bred on these farms and they might get in. (4) Most significantly, genetic diversity is broad within any species and there will be local mahseer strains best adapted to some rivers; these will be swamped if single strains of mahseer are stocked. This matters a lot in terms of protecting the viability of mahseer populations.
5. MAHSEER SPECIES
Mostly, mahseer are record as ‘black’, ‘golden’, ‘silver’,. ‘blue-finned’, etc. We need to get rather more accurate at identifying species to assess their extent and the right ones to stock (or avoid stocking). Steve Lockett and I are working on this, and I hope to circulate a simple ID guide at some stage shortly. But I can’t find good info on Tor kulkarnii (the dwarf maheer). The main reference is Menon (1992), but I can’t track that down or any other good info. Fishbase does not give a lot. Anyone care to share info, better still get me electronic or hardcopy of the Menon (1992) reference? Any help appreciated!!
Looks like Don Smith and Owen may meet up with me and Steve Lockett when we’re in Bangalore… should be a great chat! I guess Steve is setting this up right now as he’s already in India.
Sorry for the long post!!!