Frozen Striped Bonito (Sarda orientalis) – Industry Knowledge

    Striped bonito (scientific name: Sarda orientalis), also known as oriental bonito, is a medium‑sized predatory fish belonging to the family Scombridae (mackerels, tunas, and bonitos). It is a coastal pelagic species found in tropical and subtropical waters of the Indo‑Pacific region, ranging from East Africa to Japan and throughout Southeast Asia to Australia.

    The species is easily identified by its streamlined, torpedo‑shaped body and the distinctive 8‑11 dark, narrow oblique stripes running along its back and sides – a feature that gives the fish its common name. The back and sides are steel blue, with the belly whitish. Striped bonito can grow up to 102‑117 cm in total length and reach a maximum weight of approximately 10.65 kg.

    As a fast‑swimming, highly migratory species, striped bonito is an active predator feeding on clupeoids, other small fishes, squids, and decapod crustaceans. It inhabits coastal and offshore waters at depths ranging from the surface to approximately 167 metres.

    Striped bonito is an economically valuable fishery commodity in several regions. It is caught using a variety of methods, including hook and line, pole and line, gillnets, purse seines, trolling gear, and set nets.

Key Producing Regions:

    In India, striped bonito forms a seasonal fishery along most coasts, with Kerala contributing the maximum share of approximately 65.6% of the all‑India annual average catch of 849 tonnes, followed by the Andaman and Nicobar Islands (23.4%) and Gujarat (6.6%).

In Oman, striped bonito constitutes an important part of the country's fisheries alongside other small tunas, with annual catches averaging 1,000 tonnes.

    In Japan, the species is taken by various gear including trolling gear, pole and line, purse seines, and set nets, though there is no exclusive fishery targeting striped bonito.

Global Catch Trends:

    FAO capture production data for Sarda orientalis shows notable fluctuations over the years, with annual catches ranging from under 100 tonnes to over 2,000 tonnes. The species is often landed alongside other tuna and bonito species, making species‑specific catch data less precise in some regions.

Market Applications:

    Striped bonito is marketed mainly fresh, but also processed as dried‑salted, canned, and frozen. The fish is found in fish markets across its distribution range, including in Cebu, Philippines.

Export Destinations:

    Frozen striped bonito products – particularly whole round, loins, and fillets – are exported from China, Vietnam, and other producing countries to diverse markets including Southeast Asia, Europe, the United States, Japan, South Korea, Australia, South Africa, and the Middle East. Chinese suppliers, particularly from Fujian and Zhejiang provinces, play an active role in the global frozen striped bonito trade.

Product Specifications:

    Frozen striped bonito is typically available in whole round form, with common size grades including 300‑500g, 500‑1000g, 1‑2kg, and 1.5‑3kg. Products are offered in both IQF (Individually Quick Frozen) and BQF (Block Quick Frozen) formats, with standard shelf life of up to 540 days when properly stored at -18°C.

HS Code Classification:

    Frozen striped bonito falls under HS code 03034300 (frozen skipjack or stripe‑bellied bonito).

    Striped bonito is widely recognised as a nutrient‑dense seafood choice with significant health benefits.

High‑Quality Protein:

    Striped bonito is an excellent source of complete protein. The crude protein content in the back muscle ranges from 22.86% to 24.65%, making it one of the more protein‑rich fish species available.

Omega‑3 Fatty Acids:

    Striped bonito is particularly rich in polyunsaturated fatty acids, with studies reporting polyunsaturated fatty acid content as high as 36.62% of total fatty acids. The fish is especially abundant in DHA (docosahexaenoic acid), with DHA levels in muscle ranging from 19.2% to 27.6% of total lipids. DHA is a long‑chain omega‑3 fatty acid essential for brain function, cardiovascular health, and reducing inflammation.

Low Fat Content:

    The crude lipid content of striped bonito muscle is relatively low, ranging from 0.8% to 3.2%. The crude fat mass fraction in the back muscle is 1.41% to 2.51%, making it a lean, heart‑healthy protein source.

Essential Amino Acids:

    The essential amino acid mass fraction in striped bonito muscle is approximately 35.10%, with an essential amino acid index of 0.90, indicating a well‑balanced amino acid profile that closely meets human nutritional requirements.

Key Nutrients Summary:

Freezing Methods:

Striped bonito is typically frozen using one of two primary methods:

Boat freezing (sea‑freezing)

The fish is frozen directly on board at -18°C immediately after capture, preserving maximum freshness and quality.

Land freezing (factory freezing)

The fish is transported to shore‑based processing facilities and frozen using IQF or BQF technology.

Product Forms:

Quality Considerations:

    Striped bonito has a relatively high histidine content. If the fish is not handled with proper freshness and processing protocols, bacteria can convert histidine into histamine, which poses a food safety risk. Therefore, rapid chilling and strict temperature control from capture through processing and cold chain are essential to maintain product quality and safety.

Thawing Instructions:

    Once thawed, striped bonito should be cooked or processed within 24 hours and should never be refrozen.

Culinary Uses:

    Striped bonito is versatile in the kitchen. Its firm, dark red flesh holds up well to grilling, frying, and baking. It is particularly popular in Vietnam, where it is grilled and enjoyed as a common, affordable fish. It is also used in canned products, dried‑salted preparations, and as a raw material for fish sausages.

    Striped bonito is primarily a wild‑caught species, with no significant aquaculture production currently recorded. As a result, sustainable fisheries management is essential to maintain healthy stocks.

Fishing Methods:

    The species is caught using hook and line, pole and line, gillnets, purse seines, trolling gear, and set nets. In India and Sri Lanka, drift nets (gill nets) are the primary gear used in the Indian Ocean fishery.

Stock Status:

    While striped bonito is not currently listed as a threatened species, it is considered vulnerable to extinction if declines in biomass or numbers exceed thresholds over a period of 10 years or three generations. This underscores the need for continued monitoring and science‑based management.

Management Recommendations:

    Given the species' importance in regional fisheries, sustainable management measures should include:

    Monitoring of catch and effort data

    Regulation of mesh sizes to allow juvenile fish to reach maturity

    Seasonal closures during peak spawning periods

    Science‑based quota setting