For a commercial fishing enterprise operating throughout the year, what specific category of income or wealth derived from marine resources is subject to Zakat calculation, and at what annual threshold?

For a commercial fishing enterprise operating throughout the year, the specific category of income or wealth derived from marine resources that is subject to Zakat calculation falls under Zakat on Trade Goods (Amwal al-Tijarah). This category applies because the enterprise's primary activity involves acquiring marine resources (fish) for the purpose of trade and profit generation, making the fish effectively commercial inventory. Zakat is levied on the enterprise's total net tradable assets, which include the value of unsold fish inventory held for sale, cash in hand and at bank, and receivables, after deducting any immediate, short-term liabilities (like outstanding operational expenses or short-term debts). The fishing vessel, equipment, and other fixed assets used for operations are not themselves subject to Zakat as they are instruments of production, not goods for sale. The Zakat rate for Amwal al-Tijarah is 2.5% (one-fortieth) of these net tradable assets. The annual threshold, known as Nisab, for this category of Zakat is equivalent to the monetary value of 87.48 grams of pure gold or 612.36 grams of pure silver, whichever of these two values is lower on the Zakat due date. The Nisab must be met or exceeded by the enterprise's net tradable assets for a full lunar year, known as a Hawl, before Zakat becomes due. For example, if on the designated Zakat due date, the net value of the enterprise's cash, receivables, and unsold fish (intended for sale) after subtracting immediate liabilities exceeds the Nisab value and has maintained this threshold for a full lunar year, then 2.5% of that net value is due as Zakat.