Sado Island Oyster Farming Hit by Predatory Black Porgy
Farming operations on Sado Island’s Lake Kamo face severe disruptions after rising water temperatures drove predatory black porgy populations to consume cultivated oysters, reducing regional yields by roughly two-thirds over a three-year span. Local fisheries officials attribute about 30 percent of that total drop directly to the surge in black porgy predation as warming waters increase the fish’s metabolic activity in the brackish lagoon.
Low Commercial Value Complicates Population Control
Fishermen historically avoided targeting the species because low market prices classify black porgy as a low-utilization or unutilized fish, leaving local populations largely unchecked. Prefecture fisheries researchers at the Sado Marine Fisheries Technology Center noted that shifting ocean temperatures accelerated fish activity levels across the inland lake. Without steady commercial demand to incentivize large-scale catches, the multiplying fish continued unchecked inside the key aquaculture grounds, prompting regional producers to seek alternative countermeasures.
New Culinary Recipes Aim to Create Market Demand
Local restaurant owners and chefs gathered on Sado Island to design new culinary recipes that elevate the profile of the underutilized fish and build commercial demand. At the Sea-Class Gourmet Sado event, local dining establishment MelePalaKaiko served fried black porgy tacos featuring chili sauce, shredded cabbage, sliced onions, and mayonnaise inside tortillas. Store owner Noriko Ike stated that local fishermen expressed strong appreciation for the recipe development efforts, which brought public attention to the oyster destruction crisis. Cooperative head Hirobumi Yamamoto indicated that establishing a steady commercial market for the fish will naturally drive down the predatory population.
Oyster Production Drops as Black Porgy Numbers Rise
How much did oyster production drop on Sado Island?
Production fell from approximately 69 tons of shelled oysters during the 2021–2022 harvest year down to about 21 tons in the 2024–2025 period, according to the Lake Kamo Fisheries Cooperative.
What caused the black porgy surge in Lake Kamo?
Researchers at the Sado Marine Fisheries Technology Center stated that rising seawater temperatures increased the metabolic activity and overall presence of black porgy in the brackish lake.
How are local businesses preparing the fish for consumers?
Chefs like MelePalaKaiko owner Noriko Ike prepare the catch by bleeding the fish immediately after landing to eliminate odors, then serving the fried meat in tacos with chili sauce and fresh vegetables.
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