Though well sampled, there was no evidence for spawnBulletin of Marine Science Past studies have shown striped marlin larvae to occur primarily in waters of the northwestern Pacific, southwestern Pacific (Howard and Ueyanagi, 1965 Matsumoto and Kazama, 1974 Nakamura, 1985), and to a lesser extent in the northeastern Pacific (Armas et al., 1999). audax) for the first time off the Kona coast of Hawaii. ![]() Using this technique we have documented spawning activity for striped marlin (T. We previously reported on a technique used to identify eggs and larvae in near real-time (Hyde et al., 2005). The advent of DNA based techniques (Chow, 1994 Innes et al., 1998 McDowell and Graves, 2002 Hyde et al., 2005) has served to validate previous identification methods and to increase the throughput and accuracy of current studies. Despite the difficulty of larval identifications, the distributions and seasonality of billfish larvae have been well documented (Howard and Ueyanagi, 1965 Matsumoto and Kazama, 1974 Nishikawa et al., 1978 Nakamura, 1985). This inability to reliably identify larvae to species further complicates the collection of early life history data. Identification to species has been a particular problem for many larval istiophorids (Richards, 1974 Collette et al., 1984 Nishikawa and Rimmer, 1987 Nishikawa and Ueyanagi, 1992), usually relying upon slight differences in pigmentation (Nishikawa, 1991) and morphometric characters. Small larvae (< 20 mm TL) are somewhat common but larger juveniles are exceedingly rare. Until recently, fertilized eggs of the Pacific istiophorids remained unknown, but through the use of digital imaging and genetic identification techniques, the fertilized eggs of blue marlin, Makaira nigricans (Lacépède, 1802) and shortbill spearfish, Tetrapturus angustirostris (Tanaka, 1915) have been described. This finding has important ramifications for fishery management as striped marlin represent a significant portion of the billfish catch in the Hawaii-based longline fishery.ĭespite their importance in commercial and recreational fisheries, relatively little is known concerning the early life history and reproductive strategies of billfishes (Istiophoridae and Xiphiidae). This represents the first detection of spawning activity in an area that historically has been regarded as only nursery habitat for this species. Additional analysis of DNA sequence data shows that these larvae all have unique mitochondrial haplotypes indicating they each had different mothers and were not the result of a single chance event. Using this method we have unambiguously identified seven striped marlin larvae from Hawaiian waters. We recently presented a DNA based method of identification for near real-time processing of ichthyoplankton samples. ![]() Unfortunately, as the early life history of marine fishes can play an important role in reproductive success and management strategies, we are potentially missing or confounding valuable data by misidentifying specimens. Traditional use of morphology and pigment based characters for species separation of larvae can fail when faced with moderate levels of intra-specific phenotypic plasticity. Istiophorid billfishes are notoriously difficult to identify to species, especially early life history stages. Hyde, Robert Humphreys, Jr., Mike Musyl, Eric Lynn, and Russell Vetter Abstract BULLETIN OF MARINE SCIENCE, 79(3): 683–690, 2006Ī central north Pacific spawning ground for striped marlin, Tetrapturus audax John R.
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