WAITAKI TRAGEDY

Evening Post, Volume CXX, Issue 1, 1 July 1935, Page 10

WAITAKI TRAGEDY

SPAWNING SALMON DIE

A GRAPHIC DESCRIPTION

FISH-LADDER PAILS

Not much has been heard recently about the big canning industry which was to follow the introduction of the quiiinat salmon to New Zealand, but the fish have increased and spread in a manner which leads to the conclusion that in time there would be at least an addition to the local- industries of New Zealand in some degree, and" the failure of the fish-ladder at the Wailaki hyro-electric dam is a matter which should be thoroughly investigated and remedied if possible. It is moreover a tragedy for the salmon. A WASTED ACHIEVEMENT? This is not a matter which would in the ordinary way interest others than anglers, and it may be pointed out to those who do not know that the Waitaki was the first stream in which quinnat salmon were successfully acclimatised in New Zealand, an achievement which was warmly applauded by pisciculturists in England and the United States. Perhaps the habits of these salmon should also be described before the tragedy of the failure of the dam can be fully realised by the average reader. Descending the stream as smolts, the young salmon come from the spawning grounds to the sea, where they remain until of spawning age, and then reascend the river to the cold snow-ted tributaries from the Southern Alps. The original spawning runs were made in the Hakataramea River, at the hatchery where the first ova were dealt with. The "Haka" is a triI butary of the Waitaki and joins it just below the new dam, and annually there is a spawning run in that stream, but from the first there were a few salmon which made their way I up the main river, and. latterly the 1 numbers which have gone to the headwaters of the tributaries above the dam had increased until this year. Cold water and gravel beds are essential to successful spawning, after which the fish die. It may be that a few of | those fish which are' very late in eni tering the mouth of the river to spawn | recover sufficiently to reach the sea. j but the battles over spawning grounds, the long trip to the headwaters of the tributaries, and the tremendous labour of shovelling away gravel with their I snouts leave most of the.fish battered i wrecks, with only sufficient vitality to spawn. The fact that these salmon, at least in so great a majority that the residue is negligible, die after spawning should be kept in mind. INSURMOUNTABLE WALL. j It will be recognised that any added obstructions to the upstream run to the spawning grounds intensify the difficulties of the salmon, but when they find an insurmountable wall confronting them, and when the main outflow from that wall —salmon always keep in the strong currents when travelling—is a powerful, jet leading only to the turbines if they could force their way in, the frustrated fish probably destroy each other in considerable numbers in the endeavour to find individual spawning grounds in the congested pool below the dam. There is also the fact that the ova deposited in the warmer, slower water of the main river at this point are not likely to hatch out to the same percentage as if the fish had reached their natural spawning grounds., Another point is whether the smolts coming down since the dam was erected have been able to find their way past the'dam to the sea. It is more likely that, with the inflows to the turbines protected by netting, they would eventually find the outlet of the fish-ladder than the adult fish would find the inlet. Smolt have even gone down the water race to the Oamaru reservoir, a distance of twenty miles. But unless the adult fish get up, the young ones will not be there to come down. A FIRST-HAND STORY. With these points in mind the following account of the frustrated attempts of the big run of salmon during the past spawning season in the Waitaki will prove the possibility of the loss of the Waitaki as a soui-ce of salmon angling or industrial revenue. It is written by a resident of the district who is not only a well-known angler, but one who has taken an active interest in all piscatorial problems over most of his life, and as he feels about the matter, so he writes. He quotes' watchers who were seldom away from the ladder during the run as stating definitely that in their opinion not even one salmon made the ascent. A few netted fish were put in the centre pool of the ladder—which is a rising chain of pools—but they went down again instead of up. BALKED FISH. "After the salmon had been running in the Waitaki a little over a month," he writes, "and I had heard that there were a large number below the dam trying to make their way upstream, I took a party of Christchurch visitors up to look over the works, and incidentally -have a good look at the salmon and see if they were going up the fishladder. We went through the power house and had a look over the side at the pool below the dam, and could see dozens o^ salmon 'porpoising' in the swift water boiling below." "Then a climb up the ladder and through the tunnel to the north bank, where there were hundreds of fish playing • and a great many nosing against the concrete trying to find a way round. I hold no brief for the quinnat salmon; in fact, like a great many other trout fishermen, I hate the sight of them, as I consider that they have spoiled' the Waimakariri, Rakaia, Rangitata, and Waitaki for trout fishing; but no one .could look at those fish and not-.feel sorry for them. After watching for about half an hour I shepherded my party back to the power house intending to come home, but on the way through the buildings we met one of the start who asked me if I would like to go down below and have a look at the salmon from, water level. BLEEDING SALMON. "He produced a key and took the whole party of six down, under the turbines as it were, and then it was that the tragedy of the fish-ladder was revealed. We stood just over the water as it rushed out after having done its work in turning the machinery, and about two feet above the river. With every surge of the backwash dozens of salmon would come in and dash against the concrete, trying to find a way up, and looking at them so closely one could see their bruised and bleeding noses. "A little to one side was a stream of water, evidently an overflow from somewhere inside, which dropped about ten feet into a huge concrete tank. There were about a dozen salmon in this tank, and every minute or so one would make a rush, throw itself into the air, and try madly to scale the wall. Splashed on this wall in all direction were big patches of blood left by these fish in their mad attempt to get upstream. After watching about a quarter of an hour I felt positively sick. The sight was equal in my mind to the spectacle of a large number of women who, aften having booked ac-.

commodation at a nursing home and travelled many miles, found the home closed and the gates locked. REASONS FOR FAILURE. "I have discussed the matter with a great many salmon and trout fishermen as well as with one or two officials and the conclusions I have come to are that, firstly, the ladder is altogether in the wrong place, if not on the wrong side of the river. Salmon travelling upstream always keep well in the current and the entrance to the fish ladder is in the quietest and stillest part of the water. Secondly, the water supply for the ladder is not onequarter large enough to attract a salmon; it is only a very small quantity of water and unless a salmon actually wandered into it accidentally it would not noiice it, the stream being only about four feet wide with nothing to guide a fish into it. Several small trout went up the ladder and two or three actually went right up and into the lake, which would seem to bear out the idea that there is not enough water for a salmon. BELOW THE DAM. "Last week I went over to the 'Haka' River, where the Government Hatcheries are, to see how Scotty Main was getting on with his stripping. I found to my surprise that it was all over. It usually takes a month or more to get the supply of eggs required, but this season, on account of the dam blocking the fish from going upstream to their usual spawning beds, there was such a rush of salmon into the 'Haka' that the two men were unable to handle them, as many as 100 and over coming into the traps every day. From the hatcheries down to the mouth, a distance of about two miles, there was a horrible sight. Hundreds of dead and dying salmon were lying on the shingle aud half in and "half out of the water. As I said before. I hold no brief for the quinnat, but before next season I hope someone will move in the matter. In the main stream from Kurow to Otekaike, a distance of about ten miles, the bank of the river is lined with rotting fish, some of them up to 401b in weight.' What a waste!"