Global Distribution of the Giant Squid Architeuthis dux: A Systematic Review with Special Focus on the Sea of Japan Hotspot

Abstract

The giant squid (Architeuthis dux) remains one of the most elusive deep-sea megafauna. This paper presents a systematic review of confirmed records on a global scale, documenting a total of 836 specimens through late 2025. We focus on the Sea of Japan, which has emerged as a biological hotspot following an unprecedented 15-month period where 57 specimens were recorded. These events are analyzed through the influence of the Tsushima Warm Current, revealing a 'thermal trap' where water temperatures exceeding 15°C impair hemocyanin oxygen transport, leading to seasonal strandings. Furthermore, the study evaluates the transition from classical sighting data to modern detection frameworks, including environmental DNA and stable isotope analysis. Our findings suggest a return to historical baseline patterns following recent thermal anomalies, providing a consolidated framework for the future conservation of deep-sea biodiversity.