This country, however, does not produce some fine fishes found in other countries, and some excellent fresh-water fishes, such as the pike, the perch, the roach, the barbel, the gardon [chub], and the gudgeon. Minnows, also, bullheads, and verones [minnows] are not found there, also no loches, or they are very rare.
On the other hand, the lakes of this country contain three species of fish which are found nowhere else. One is a sort of trout, called the salares, which are longer and rounder than trout, and which are white, close grained and good flavoured. The tymal, commonly called the umber, resembles the former kind of fishes, except that it is distinguished by a larger head. There are others which very much resemble the sea herring, both in shape and quality and in colour and taste. A third sort, exactly resembles the trout, except that it has no spots. The first sort is called Glassans, the second Cates, and third Brits. These three fish make their appearance in the summer only, and are never seen in the winter’.
It would appear from this text that the freshwater fish present in Ireland during the twelfth century included salmon, brown trout, eel, shad (probably both Twaite and Allis), sea and river lampreys, and almost certainly the brook lamprey, as the habitats of the three overlap. Amongst these early settlers, the sea and river lampreys, Atlantic salmon and the brown trout are anadromous, i.e. spend most of their lives in the sea but migrate to fresh water to spawn.
Other anadromous species arrived in Ireland from more southerly seas at the end of the last glaciation. They were the Allis and Twaite shads. Resembling herrings and found in shallow coastal waters and estuaries in western Europe, they run up the lower reaches of the larger rivers during the spawning season. In Ireland, however, the Allis shad has no known spawning site left. In fact, it is not certain whether the species is still here, as its presence is only supported by a few post-1960 records – in the Foyle estuary, Co. Derry, at two north Mayo sites, in the River Corrib, Co. Galway, and at one site in Cork. The Twaite shad shares the same coastal distribution and probably still breeds in a few Irish rivers such as the Nore, Suir and Barrow, all flowing into Waterford Harbour and the Cork Blackwater. When locked away in remote lakes, it developed into different subspecies, the Killarney shad, Alosa fallax killarnensis, being one of the most celebrated. Known locally as the ‘goureen’, it is restricted to Lough Leane and Muckross Lake, Co. Kerry, where it has been preserved for several thousand years. The smelt, also a coastal dweller in western Europe, imitates the anadromous behaviour of the shads. In Ireland it spawns in the rivers Shannon, Fergus and Foyle and perhaps at various sites in rivers Suir, Nore and Barrow. The remaining native euryhaline fish to arrive after the last Ice Age was the European eel, a catadromous species (one that migrates from rivers to the sea to spawn). Eels live in lakes and rivers and spawn in the Sargasso sea, after which the baby eels return to Ireland.
Once in Ireland the brown trout evolved a series of varieties, some of which are collectively known as sea trout (sometimes ascribed subspecific status as Salmo trutta trutta but not fully accepted by all scientists) with anadromous habits, and the darker, landlocked non-anadromous brown trout (sometimes ascribed the subspecific status Salmo trutta fario, again not fully accepted by all scientists). The latter have given rise to many other different varieties. For instance in Lough Melvin, Co. Leitrim, there are three clearly distinct stocks of brown trout: the ferox (Salmo trutta ferox), the gillaroo (Salmo trutta stomachius) and the sonaghan (Salmo trutta nigripannis). They are genetically different and spawning takes place in different parts of the lake.
Arthur Went who, apart from being the scientific advisor on fisheries to the Irish Government, was a specialist in questions concerning the history of fish in Ireland, believed that the pike was an introduced species, basing his arguments on an examination of historical documents including the statement by Cambrensis (see here). Cambrensis had a reasonable knowledge of Irish lakes and rivers. He mentions the pike as absent from Ireland. A further clue as to the late introduction of the species is supplied by the great historian Roderic O’Flaherty, who clearly ascertained that in 1684 the pike was absent from Connacht when he wrote:
‘The water streames, besides lampreys, roches, and the like of no value, breed salmons (where there is recourse to the sea), eels and divers sorts of trouts. There was never a pike or bream as yet engendered in all this countrey, nor in the adjacent parts of Mayo or Galway counteys.’55
The pike must have been brought into Ireland some time before 1682, for historical records state the presence of weirs for eels and pike on the River Camoge at the Abbey of Monasternenagh, near Croom, Co. Limerick, at the time of the Abbey’s dissolution.56 The Civil Survey of Ireland (1654–6) also noted the River Camoge as well as other tributaries of the River Maigue had pike.57 Its widespread distribution today should not be mistaken for a sign of long-lasting presence in the country. As a rapid coloniser, the species was able, once introduced, to spread throughout freshwater systems over a short period of time.53
Went stated that there was no evidence as to whether the perch was a native species or not. However, since the remark by Young in Tour in Ireland that perch first ‘swarmed in the Shannon’ in about the year 1770, the geographic distribution of the species and its numbers have increased considerably.58 The roach, often confused with the rudd, was introduced to the River Blackwater, Co. Cork, in 1889. The barbel and ‘gardon’ – almost certainly the chub – referred to by Cambrensis are not present in Ireland today. The gudgeon, however, which the Welshman reported absent in the twelfth century, is now claimed to be a native species as are minnows – also called ‘verones’ by Cambrensis – and the stone loach.
The ‘salares’ of Cambrensis is almost certainly one of the pollan or whitefìsh species, restricted to five of the largest Irish lakes – Lough Neagh, Upper Lough Erne (no records this century), Lower Lough Erne (small but precarious population59), Lough Derg and Lough Ree (no recent records). Absent from Britain and elsewhere in western Europe, its presence in Ireland is outlandish, and it is possibly a relict from a once wider distribution. Today it is only found in the coastal areas and lower reaches of arctic rivers in eastern Europe, Asia and western North America. Once thought to be an intermediate between the powan and the vendace – both absent from Ireland – it has the status of an endemic Irish subspecies of the Arctic cisco which lives in Alaska, Coregonus autumnalis pollan. These two ‘conspecifics’, the Arctic cisco and Irish pollan, have probably been separated for about 10,000 years since the first pollan – a cold water species able to withstand life at the edge of ice sheets – are thought to have entered Ireland through the Shannon system at the start of the postglacial period.60 Although the pollan are anadromous throughout most of their northern range, in Ireland they are virtually non-migratory, and restricted to fresh waters. The species named the ‘tymal’ by Cambrensis is the grayling which, in fact, is absent from Ireland. Was it ever present or did the observer misidentify the species? It is impossible to say.
The ‘spotless’ fish referred to by Cambrensis is the Arctic charr, whose name is derived from the Gaelic ‘tarr’, meaning belly. The male belly colour ranges from pink to bright vermilion, as pointed out in two Irish names, tarr-dhearg, meaning ‘red-bellied’, and ruadh bhreac, meaning ‘red trout’.52 The female is drabber than her male counterpart whose bright red colour plays an important role both in courtship and defence of the breeding territory. Charr, more than most other freshwater fish, excite the imagination of naturalists who know them as ‘glacial, or Ice Age relicts’, i.e. survivors of the Ice Age. They inhabit the deep dark, oligotrophic (nutrient-poor) formerly glaciated lakes which they invariably share with brown trout – although in Ireland, they often break from their austere habitats and are found in shallow and eutrophic (nutrient-rich) waters. The Arctic charr is distributed throughout the northern hemisphere with both anadromous and non-anadromous populations. In Ireland, it is non-anadromous. Like the smelt and Twaite shad, it is classified as an ‘endangered and vulnerable’ species – the pollan, Killarney shad and Allis shad are ‘endangered’ species while the sea lamprey, river lamprey and brook lamprey