Why are New Zealand striped marlin much bigger than the ones caught in Hawaii?
Something that is on my fishing bucket list is to catch a large New Zealand striped marlin. I have caught quite a few Hawaiian striped marlin, both as a deckman and as an angler. I even have an IGFA 5-1 club line class record, weighing a 116-pounder on 20-pound stand up aboard the Absolute with Capt. Marty Sands and deckman Chris Whittingham.
Why are the New Zealand striped marlin significantly larger than the striped marlin we catch in Hawaii? The answer is not a simple one, but rather a combination of many factors.
Genetics and geography: research on the genetics of striped marlin suggests that there are three separate stocks in the Pacific based roughly around the Sea of Japan, Mexico/Southern California, and the southwest Pacific, including New Zealand and Australia.
Even if you assume the Southwest Pacific stock has some genetic advantage over the others and a greater growth potential, why does Australia, proven to share the same stock as New Zealand, hold no striped marlin line-class records? The answer to this question may be an accident of geography.
New Zealand’s North Island and South Island span a wide range of climate and water temperature changes, from near tropical in the north to almost sub-Antarctic in the deep south. New Zealand represents the southern extent of the striped marlin’s water temperature tolerance, and the marlin really move in when warm currents lick down from the tropical waters to the north. Water temperatures of 64-68 degrees Fahrenheit are standard for striped marlin fishing in New Zealand,
Since bodies of greater size conserve core heat more efficiently, larger fish can stand cooler water temperatures.
New Zealand’s location in the lower latitudes acts as a thermal sorting sieve for marlin size, and in a normal year only the larger fish feel comfortable there. Striped marlin in New Zealand waters usually average about 200 pounds and have been recorded over 500 pounds. In Australian waters further to the north, the water is warmer, but the average size of striped marlin is significantly smaller.
The big marlin that migrate to New Zealand each year are rewarded by easy living in rich, temperate waters. Well-oxygenated cool water and a nutrient-filled continental shelf create a high-quality feeding ground that marlin can use to beef up, often packing on 45 to 65 pounds before moving to northern spawning grounds.
Another advantage for striped marlin in New Zealand waters is a 200-mile commercial-free economic zone where these great billfish are protected from long-liners. Local recreational fishermen have historically defended these no-take zones without compromise.
The largest striped marlin caught on rod and reel all come from New Zealand waters. The International Game Fish Association (IGFA) keeps records, and 20 of the 22 striped marlin line class world records are held by anglers in New Zealand, including all the heaviest fish caught on line from two-pound to 130 pound breaking strain for men, and from four, eight to 130 pounds for women. The women’s two-pound test record was from Cabo, and the six-pound test was from Costa Rica. The IGFA all-tackle record for men is a 494.0-pound fish on 50-test line, and for women it’s a 423.4-pound fish on 50-test line.
The Hawaii state record for a striped marlin is a 212-pound fish, with the Maui County record a 188.4-pound fish aboard the Start Me Up with Capt. Timster Putnam.