International Court of Justice — Jurisdiction — Optional Clause — Statute of the Court, Article 36(2) — Declaration accepting jurisdiction of the Court — Reservations — Right of State making declaration to define scope of acceptance of jurisdiction — Whether reservations to be construed restrictively — Distinction between substantive law and rules governing jurisdiction of the Court — Principles to be applied in interpretation of declaration and reservations — Intention of State making declaration — Principle of good faith

International Court of Justice — Procedure — Preliminary objections — Whether objection possessing an exclusively preliminary character — Duty of the Court in dealing with preliminary objections

Sea — High seas — Jurisdiction — Fisheries — Conservation measures — Arrest of Spanish vessel by Canada outside Canadian waters — Legality — Whether dispute falling within jurisdiction of International Court of Justice

Environment — Maritime environment — Fisheries conservation — Limit of conservation measures — Compatibility with regime of the high seas