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Although the ferox of Scottish Highland lochs (lakes) have long captured the interest of both laymen and scientists, no previous investigation of their biology or ecology has been undertaken. This paper is based on 141 ferox from 22 lochs collected during the last 22 years and the results from a recent investigation into their status and distribution. When the features of their environment and the distribution of what is apparently their main food source, the arctic charr, were investigated, two essential conditions governing the occurrence of ferox emerged and a third appeared to be important: (i) oligotrophic waters; (ii) the presence of charr and (iii) a large loch (over 100 ha in extent). Typically, ferox grow slowly during the first third of life but on reaching what may be a critical length enter into a phase of rapid growth and may eventually reach a size and age very much greater than that of the individuals in the normal trout population from which they arise. This pattern of growth contrasts markedy with that of large, fast growing brown trout from eutrophic waters in Scotland which do not reach the same extremes of age or size. |
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