could obtain in the course of the winter
months during their sojourn in the rivers. As soon as he had hauled the
fish ashore, he made peculiar marks in their caudal fins by means of a
pair of nipping-irons, and immediately threw then back into the water.
In the course of the following fishing season great numbers were
recaptured on their return from the sea, each in its own river bearing
its peculiar mark. "We have also," Mr Young informs us, "another proof
of the fact, that the different breeds or races of salmon continue to
revisit their native streams. You are aware that the river Shin falls
into the Oykel at Invershin, and that the conjoined waters of these
rivers, with the Carron and other streams, form the estuary of the
Oykel, which flows into the more open sea beyond, or eastwards of the
bar, below the Gizzen Brigs. Now, were the salmon which enter the mouth
of the estuary at the bar thrown in merely by accident or chance, we
should expect to find the fish of all the various rivers which form the
estuary of the same average weight; for, if it were a mere matter of
chance, then a mixture of small and great would occur indifferently in
each of the interior streams. But the reverse of this is the case. The
salmon in the Shin will average from seventeen pounds to eighteen pounds
in weight, while those of the Oykel scarcely attain an average of half
that weight. I am, therefore, quite satisfied, as well by having marked
spawned fish descending to the sea, and caught them ascending the same
river, and bearing that river's mark, as by a long-continued general
observation of the weight, size, and even something of the form, that
every river has its own breed, and that breed continues, till captured
and killed, to return from year to year into its native stream."

We have heard of a partial exception to this instinctive habit, which,
however, essentially confirms the rule. We are informed that a Shin
salmon (recognized as such by its shape and size) was, on a certain
occasion, captured in the river Conon, a fine stream which flows into
the upper portion of the neighbouring Frith of Cromarty. It was marked
and returned to the river, and was taken _next day_ in its native stream
the Shin, having, on discovering its mistake, descended the Cromarty
Frith, skirted the intermediate portion of the outer coast by Tarbet
Ness, and ascended the estuary of the Oykel. The distance may be about
sixty miles. On the other hand, we are