HOW TO CATCH THE TUNA OF YOUR DREAMS

Tuna are very special fish. Evolved far beyond the capabilities of other fish, tuna are the Olympic athletes of the piscine world — in both the marathon and sprint divisions. The physiology of these exquisite fish is remarkable, with increased oxygen intake from a greatly enlarged gill system, a blood system incorporating a heat exchanger, a warm body that enhances muscle performance, and streamlining that surpasses even the best jet aircraft.

A tuna’s firm body is torpedo-shaped and mostly muscle. In fact, their gut system is proportionally tiny, meaning they process their food quickly and need to keep eating regularly to fuel their highspeed swimming. Like other animals, tuna have different types of muscle for different purposes, but here again, tuna are different, even from other fish.

EXTRAORDINARY MUSCLE

Located centrally, either side of the backbone, tuna have bands of what is known as ‘slow-twitch’ red muscle, which is what they use for most of the day, including regular swimming. This oxygen-saturated, dark-red muscle can keep going tirelessly, and is what the tuna use to power their long-distance migrations, frequently across the borders of multiple countries. However, surrounding this dark muscle,