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Delphi Fishery Report - 2007

Solid salmon catches - 415 for year - but no increase over recent average

With 415 salmon caught at Delphi in 2007, the season would have been regarded as solid if unspectacular under the old salmon management regime, which allowed coastal drift nets to take most of Ireland’s returning fish.

But in the light of the new drift net ban, which has resulted in tremendous rod catches on some Irish rivers this year, the Delphi catch must be regarded as disappointing.

Although the average weight of the one-sea-winter grilse improved a bit and there were some very good fishing days, with tremendous individual catches, a lot more fish had been expected to run into Delphi. This was especially so given the largely suitable weather throughout the summer, with plenty of rain.

A mediocre spring salmon run was followed by yet another very late grilse run, with the peak of the fishing coming in late July instead of the more normal peak in late June.

The catch statistics overleaf clearly show an upward shift in the size of grilse by virtue of the net ban. But there was still a large component of ludicrously small fish, some in quite wretched condition, which indicates that oceanic feeding problems persist.

A new Delphi record was set with a salmon weighing just 13 ounces, including the tag. In Norway a fish of 12 ounces was reported.

The Delphi grilse, both hatchery and wild, were significantly bigger than the Burrishoole stock reared at Delphi. Very few Delphi fish weighed less than 2½ pounds, whereas dozens of the Burrishoole fish weighed less - or much less. Nearly all the very small fish were males.

The average weight of spring salmon fell to 7.66 pounds, the lowest ever recorded at Delphi (see separate story).

One pleasing aspect of the season was the almost complete absence of net marks on fish. Only four fish at Delphi were net-marked and two of those were probably attributable to (still legal) estuary nets. In the past up to 50% of grilse were damaged by nets. It appears that the drift net ban was very effectively policed and huge thanks are therefore due to the Navy and to the staff of the regional fisheries boards for protecting the stock offshore and inshore.

Over 84% of all Delphi salmon were caught on fly – or 93% if the fish caught during the end-of-season party are excluded. In terms of the number of salmon caught per rod day, 2007 was down by comparison both to 2006 and to the 10-year average.

Fishing effort remained very steady, with high occupancy of the 8-12 available fishing slots for most of the season. But there was no great rush of extra booking enquiries as a result of the new net ban, showing that the angling fraternity still needs convincing that the ban will produce big dividends.

It is clear that, had drift netting not been stopped, the 2007 season would have been an absolute disaster.

Why were the catches not much better? Night-time protection effort was intensive and the highest for years, with no sign of major problems; so poaching cannot be the cause.

Other rivers in Connemara had exceptionally good runs, most notably on the Ballynahinch system, where the counter recorded nearly 3,000 salmon. The count was also well up at the Burrishoole research trap.

Kylemore Abbey had a good rod catch of 137, a big increase over the previous year, and reports from Screebe, Clifden and Costello indicated abnormally good numbers of salmon. To the north, the Easkey in Sligo had some spectacular days, as did the Mayo Owenmore. So there is no obvious regional problem.

The only other fisheries where the salmon catches were also disappointing were the neighbouring River Erriff (about 270 salmon caught) and the Killary Harbour draft net fishery (about 300 salmon caught), which suggests a more local problem. That problem is clearly sea lice from the local salmon farm (see later story).

Just 8 wild fish killed in whole season

We are proud that Delphi’s new wild fish conservation measures resulted in only eight wild fish being killed in the entire season. Under the new rules, all wild fish must be returned alive unless they happen to be an angler’s very first salmon of his or her life.

Three anglers did catch and kill a wild fish that was their first ever salmon. Two other wild fish died after capture and there were three other instances that can be classed as errors of judgement by anglers; in these five cases, to discourage future errors, anglers were not allowed to retain their fish.

The 90% release rate is only made possible by the presence of the hatchery fish, which have to be killed.

Delphi/Erriff experiments show that lice from salmon farms are killing thousands of wild salmon

Shocking results are emerging from experiments to measure the impact of sea lice on wild salmon. There is now hard evidence to show that lice from salmon farms are destroying Ireland’s wild salmon as well as sea trout.

In the spring of 2005 hatchery-reared salmon smolts were released from the Delphi and Erriff rivers. In each case, one group of smolts was treated with Slice (an anti-sea-lice chemical administered with food) and another group was left untreated.

Since each pair of treated and untreated groups was reared in the same circumstances and released at the same time and in the same place, any difference between the numbers of returning adult fish in the following year would be significant. Similar tests have been conducted in Norway, showing much higher survival rates for treated fish.

And since the overwhelming majority of sea lice have been shown to derive from local salmon farms, the experiment is effectively measuring the minimum damage caused by salmon farms to wild salmon. We say “minimum” because not all treated smolts take up enough chemical protection in their food. In tests up to half of them did not, meaning that the actual kill rate of the lice is probably much higher.

The results from the Erriff releases in 2005 are extremely worrying, with an implied destruction of over 90% of all wild salmon smolts from that river. About 5,000 treated and 5,000 untreated smolts were released. According to the Marine Institute’s official report, 37 adult salmon were recovered in 2006 from the treated group, but from the untreated group just 2 adults were recovered

The Delphi releases in the same year (10,000 treated and 10,000 untreated) were made 22 days later, by which time local lice levels were much reduced. Nonetheless, the impact of sea lice was significant. From the treated group there were 67.7 adults recovered per thousand smolts released. From the untreated group, 57.5 adults were recovered per thousand. This difference is statistically significant and arose despite the fact that lice levels on the farm were not very high at the time of the smolt release.

This confirms the findings of the late Dr Graham Shaw, whose review of the Killary lice situation in earlier years showed that even “low” levels of ovigerous (egg-bearing) lice on the farm in the spring - just 0.3 per fish - can have serious negative impacts on wild smolts.

The 2006 Delphi releases look set to prove even more significant. With the two smolt groups having been differentially tagged and branded, the 2007 rod catches indicate that the treated group survived many times better than the untreated group. The lice levels on the farm in April 2006, the time of smolt migration, were catastrophically high at nearly 20 times the limit laid down in the farm’s licence.

The preliminary findings indicate very serious destruction of Delphi’s untreated salmon. It would explain why the rod catch of wild fish, which were obviously untreated, was well below average instead of being much better in the wake of the drift net ban.

For the Delphi 06 smolt groups, however, there is a lot of data still to be processed and tags must be read, including those from broodstock netting and the Killary draft net fishery, before the preliminary indications can be confirmed. It will be a most important and sizeable body of data. Pending this tag work by the Marine Institute, it is premature to lock in on hard numbers. Nonetheless the situation is profoundly disturbing.

The good news is that lice levels on the farm in April 2007 were relatively low and there were improved runs of healthy sea trout finnock in the summer (see separate article). And we now treat all our hatchery smolts with Slice except for a control group of 10,000. This bodes well for the 2008 grilse run, which fishery manager David McEvoy predicts will be a bonanza.

Evidence of serious feeding problems for salmon at sea

If there was need for hard proof of the serious growth and feeding problems facing salmon out at sea, the abnormal rod catches of Burrishoole-origin fish at Delphi in 2007 provide it.

The Burrishoole stock has never been noted as a two-sea-winter (2SW) or “springer” stock, either at Delphi or in its native fishery. It has always been a small but excellent 1SW or grilse stock, with high return rates and only an occasional 2SW fish.

In 2007, however, things were different. No less than thirty five Burrishoole 2SW salmon, tagged, branded and released as smolts in April 2005, were caught by anglers at Delphi this year. One was caught in March, but all the others came in between early June and mid-July, except for one straggler in August.

In line with normal expectations for 2SW fish, most of the 35 were female, with only 6 males and one whose sex was not recorded.

What was dramatically different about them, however, was their size. They were absurdly small. One weighed just 1lb 14oz:

Weight No.

       > 2lbs 1
2lbs > 3lbs 2
3lbs > 4lbs 7
4lbs > 5lbs 6
5lbs > 6lbs 10
6lbs > 7lbs 6
7lbs > 8lbs 2
8lbs+ 1

Total 35

Two-sea-winter fish normally weigh over 8 pounds and, even by the standards of recent years, they should at least have weighed 6 pounds. Most of these fish were well short of that.

Of course it is possible that an odd one of these fish did not smoltify properly in 2005 and failed to migrate until 2006. But that is unlikely to be the case for many of them since we always cull out undersize, immature fish as well as the precocious males prior to or during the tagging process. Further, these fish ran into Delphi ahead of most of the grilse, just when the occasional 2SW Burrishoole fish of normal size usually arrive.

Perhaps we should not be surprised. The 2006 grilse catch at Delphi and elsewhere included many very small fish and the run was very late, prompting widespread speculation about problems with feeding at sea. Some observers had predicted that these problems might cause some fish to spend an extra abnormal winter at sea in order to reach sexual maturity. Whatever the cause, the tiny size of the fish is truly alarming. Over to the scientists….

New Delphi bonefishing club at Rolling Harbour, Bahamas

Peter Mantle is starting a new venture in the Bahamas – a bonefishing lodge with many similarities to Delphi. The venture is a private one and is not otherwise connected with Delphi.

The new plantation-style house will overlook a beautiful beach and is close to some of the world’s best and least exploited bonefish flats. It is due to become operational in the spring of 2009.

Many regular Delphi guests have taken a stake in the venture, which will have its own resident manager, to be recruited during 2008. Peter himself will spend a number of weeks there each year, but will continue to be based primarily at Delphi in Ireland.

Eagles sighted at Doolough

There were two sightings of eagles at Delphi during the fishing season, including one by participants on a Peter O’Reilly casting course. Once extinct in Ireland, both golden eagles and sea eagles are now being reintroduced in Donegal and Kerry.

The last golden eagle in Ireland is said to have been one that was shot in Killary Harbour in the late 19th century and which is now stuffed and mounted in a glass case in a house near Leenane.

The local habitat is ideal for the birds and we think it’s only a matter of time before they take up residence in the area.

Less welcome visitors this year were mink, the population of which seems to be growing. A trapping campaign will be restarted this winter.

More pleasingly, there were numerous sightings during the year of otters, dippers, badgers, peregrines, and the occasional pine marten. As the heather regenerates in the fenced areas of Delphi, the bird life is also increasing. But, strangely, in 2007 Delphi was almost completely devoid of bees and wasps. And butterfly numbers seemed well down, despite the growing number of wild flowers.

Very wet winter, dry spring, rainy summer

An extremely wet spawning season at Delphi, with over 20 inches of rain in December alone, caused havoc in the local area. A major landslide between Delphi and Aasleagh buried a herd of cows and damaged houses. There was also a smaller landslide above Finlough.

Four inches of rain fell on December 2nd, starting off the wettest two weeks in Delphi’s history. But things have a habit of evening out and, following a dry Christmas, there were other dry spells from late January to early Feb, and then again from mid-March to mid-April. Good rains from April 21-24 helped restore river levels for spring fishing.

May was slightly wetter than usual and in June serious rains fell at the beginning, middle and end of the month. This should have been very good for salmon fishing, but the grilse runs were late again, so not too many fish were taken. The last week of June did yield a number of good fresh springers and, fortunately, July was unusually rainy, too, which did help the grilse fishing.

A very localised cloudburst in July destroyed the bridge in Leenane. But Delphi largely escaped the downpour.

The second half of August was dry and calm, which killed off the fishing until a big flood on September 15 stirred everything up again and led to good closing catches.

With 114 inches of rain from October 2006 to September 2007, the year was very wet even by Delphi standards. But we did not experience the huge, record-breaking deluges that fell in the summer on England and the east coast of Ireland – perhaps because the airflow was largely easterly rather than the more normal, and for us soggier, westerlies.

Three new salmon centurions

Three people – George Westropp, Andy Smith and Delphi’s own David McEvoy - caught their 100th Delphi salmon in the 2007 season. And Christopher Jarman caught his 50th. Congratulations to all.

They still have a long way to go to catch Swiss fishaholic Urs Leibundgut who, with 279 salmon, now stands as the most successful salmon angler in modern Delphi history. That occasion in August was marked with champagne, which temporarily distracted Urs from his maniacal riverside endeavours.

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