01Basic concept of the closed season

A closed season is a system that restricts harvest of fish and mollusks during their spawning period to maintain population numbers. During spawning, females release eggs and males fertilize them, creating a crucial window for juvenile growth.

According to the Enforcement Decree of the Fisheries Resources Management Act, the nation designates a closed season for octopus of at least 46 days (May 16 ~ June 30). This aims to prevent excessive harvest during the peak spawning period.

However, each provincial governor may announce additional closed periods based on local spawning timing. For example, some areas of the South Sea set the period from late May to early July, while the East Sea designates mid‑June to early August.

Average spawning water temperature
18‑24 ℃
Typical spawning depth
30‑80 m
Protected age class
Adults ≥ 2 years

02Spawning and resource‑recovery mechanisms

Octopus are sensitive to temperature and photoperiod, beginning to spawn when water is 18‑24 °C and daylight increases. At that time, a female releases 5,000‑10,000 eggs per spawning event.

Immediately after spawning, eggs attach to the seabed at depths of 30‑80 m. If the water temperature stays within the optimal range, the eggs hatch within 2‑3 weeks, and the hatchlings grow within 1‑2 months.

Without a closed season, adults are over‑harvested, causing a sharp decline in spawning individuals. Consequently, the next generation’s population drops, leading to a long‑term reduction in catch, according to research by the National Institute of Fisheries Science.

South Sea coast
Jeollanam-do · Gyeongsangnam-do
50–120m
Late May ~ early July
East Sea coast
Gangwon-do · Gyeongsangbuk-do
40–100m
Mid‑June ~ early August
West Sea coast
Jeollabuk-do · Chungcheongnam-do
30–90m
Mid‑May ~ late June

03Checklist to verify before a fishing trip

1️⃣ Check the local provincial notice: each local government posts its own closed‑season dates. Before heading out, always consult the latest notice on the Ministry of Oceans and Fisheries or the fisheries information portal.

2️⃣ Assess water temperature and depth: use local Korea Meteorological Administration marine weather data and depth charts to confirm conditions suitable for spawning. If water temperature falls below 18 °C, spawning may be delayed.

3️⃣ Determine if the area is a protected zone: in zones designated by the Korea Coast Guard (protected waters or marine protected areas), harvest is prohibited regardless of the closed season.

⚠ Common Mistakes
  1. Only remembering the notice date and missing the full period– Because the start and end dates differ by region, check the entire period
  2. Even if low water temperature delays spawning, do not ignore the closed season
⏱ Golden time for successful spawning
Two weeks before spawning
Monitor water temperature and light; harvest declines before and after the closed season
Spawning day
Maintain depth of 30‑80 m and water temperature of 18‑24 °C
2‑3 weeks after hatching
Eggs hatch and juveniles become active; maintaining the closed season is essential

04Legal liability and safety notice

Violating the closed season or minimum size limits incurs fines under the Fisheries Resources Management Act. Fine amounts and periods vary by region and year, so refer to the local provincial notice for exact figures.

If caught violating the rule, authorities will issue a fine notice on site and send a penalty notice. To prevent recurrence, be sure to review the latest notice and safety guidelines before heading out.

The Korea Coast Guard will immediately suspend departure of vessels that breach the closed season. Therefore, compliance protects resources and directly impacts personal legal safety.