The South Pacific nation of New Zealand has cornered the market on record-size striped marlin. As of 2013, 20 of the 22 official IGFA line-class records for striped marlin have come from New Zealand waters, and junior record listings show a clean sweep for the Kiwis.
Considering the wide distribution of striped marlin and the popularity of this acrobatic species among anglers all across the Pacific, the concentration of trophy striped marlin in New Zealand represents a statistical anomaly that begs an explanation. 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 through tagging programs -- 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. Striped marlin frequent the waters of the northern half of the North Island only during the warmer months of summer and early autumn, usually January through April. The Three Kings Islands, about 30 miles to the north of the North Island, may hold large concentrations of forage fish that support marlin populations a bit later -- through May and even into June.
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 18-20°C (64-68°F) are standard for striped marlin fishing in New Zealand, and sea surface temperature charts directing anglers to warm-water breaks are valuable fishing tools.
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 (90 kg), and have been recorded over 500 pounds (227 kg). In Australian waters further to the north, the water is warmer but the average size of striped marlin is significantly smaller.
Occasional El Nino events reinforce this concept, when summer water temperatures along New Zealand's coasts rise more than usual. During El Nino, anglers find greater numbers of smaller-than-average striped marlin on the traditional northern grounds and the fish penetrate much further south than usual. As an example, during the exceptional hot-water season of 1999, two striped marlin were caught by anglers near Jackson's Bay near the bottom of the South Island's west coast. At approximately 45° S it was an unprecedented event, and these fish may represent the most southerly captures of striped marlin by recreational anglers.
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 20 to 30 kilos (45 to 65 pounds) before moving to northern spawning grounds.
Another advantage for striped marlin in New Zealand waters is a 200-mile (322 km) commercial-free economic zone where these great billfish are protected from longliners. Local recreational fishermen have historically defended these no-take zones without compromise.
Two decades ago, the majority of the light-tackle (under 15 kg) striped marlin world records hailed from countries other than New Zealand. Having been blessed with very large stripies, few Kiwis were previously inclined to fish the light line classes for them. Notable exceptions were Barry Hill, who in the early 1980s captured both the 8 kg and 6 kg world records, and lady angler Robyn Hall, who held the 8, 10, 15 and 24 kg women's striped marlin records in the 1970s and 1980s.
In recent years the pace has quickened. In 1996 a team on the Bay of Islands charter boat "Predator" laid a plan to try for the men's world record striped marlin on 8 kg (16 pound) line -- in those days considered to be incredibly light for New Zealand billfish. After three days of fishing off the Three Kings Islands and a final six-and-a-half hour fight, the Predator crew boated a new world record of 113 kg (249 pounds).
This capture fired the enthusiasm of a number of keen and experienced crews, and the following seasons saw a number of top boats mark up 14 new world records for striped marlin from New Zealand. Most recently, the husband and wife team of Guy and Eryn Jacobsen have taken up the banner in the last nine years and have made pretty much a clean sweep of the light line classes, holding nine world records for striped marlin between them at the time of writing.
LATE IS GREAT
Anglers focusing on record-sized striped marlin should buck the trend and focus on the months of April and May. In fact, 13 of 18 world records pulled from New Zealand's waters since 1994 were caught in these two months.
This is very late in the billfish season by conventional New Zealand standards, with most regular marlin charter work having dried up by this time. The handful of boats that pursue the big fish on light tackle are often the top local charter boats or privately owned boats crewed by friends and family of the owners and skippers, and a handful of keen anglers who relish the challenge of tackling big fish on "skinny string."
Winter's approach brings the only downside of New Zealand's late-season fishing, as the weather often becomes unreliable. Wind-against-tide situations can produce difficult fishing conditions, and fishing with light tackle will require quick maneuvering and chasing down fish.
The temperature can drop quick this time of year as well, offering the unusual scenario of chasing warm-water pelagics while rugged up in heavy clothing, wet-weather gear and sea boots. Although conditions are warm and calm on occasion, in general, late season is for the hardy types, and those that cannot cope with a bit of rough water need not apply.