13. Facts relevant when right or custom is in question.
Where the question is as to existence of any right or custom, the following facts are relevant;
(a) Any transaction by which the right or custom in question was created, claimed modified, recognised, asserted or denied, or which was inconsistent with its existence.
(b) Particular instances in which the right or custom was claimed, recognised, or exercised, or in which its exercise was disputed, asserted, or departed from.
The question is whether A has a right to a fishery.
A deed conferring the fishery on A’s ancestors, a mortgage of the fishery by A’s father, a subsequent grant of the fishery by A’s father, irreconcilable with the mortgage, instances in which A’s father exercised the right, or in which the exercise of the right was stopped by A’s neighbours, are relevant facts.