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The earliest colonisation of oceanic islands by Homo sapiens occurred ~50 000-30 000 years ago in the Western Pacific, yet how this was achieved remains a matter of debate. With a focus on East Asia, the research presented here tests the hypothesis that bamboo rafts were used for these early maritime migrations. The authors review the evidence for Palaeolithic seafaring in East Asia as the context for an experimental archaeology project to build two bamboo watercraft. Sea trials demonstrate the unsuitability of bamboo, at least in East Asia, indicating that more sophisticated and durable vessels would have been required to traverse the Kuroshio Current. Keywords: East Asia, Late Pleistocene, bamboo raft, watercraft, maritime migration, Introduction The development of seafaring in the Late Pleistocene opened up new environments for Homo sapiens. It allowed our species to expand into habitable territories beyond the continental landmasses, facilitating [...]

Meta-analysis (inverse-variance, random-effects model) involving 46 studies was used to estimate the effect size of postrelease mortality ([F.sub.r]) in six istiophorid billfish species (black marlin (Istiompax indica), blue marlin (Makaira nigricans), longbill spearfish (Tetrapturus pfluegeri), sailfish (Istiophorus platypterus), striped marlin (Kajikia audax), and white marlin (Kajikia albida)) following release from recreational, longline, and harpoon fishing gears. The studies involved 400 reporting pop-up satellite archival tags and 64 reporting acoustic (ultrasonic) tags. Despite fish being captured, tagged, and released under widely disparate conditions, locations, and gear types, [F.sub.r] was homogeneous among species. Variability in [F.sub.r] was principally due to random sampling error within studies with no evident patterns. Fifteen studies (33% of tags) indicated no mortality, and the overall summary effect size for [F.sub.r] was 13.5% (95% CI: 10.3%-17.6%). Since the random-effects model decomposed to a fixed-effect model when the between-studies variance [T.sup.2] = 0.00, results were confirmed using exact nonparametric inferential tests and sensitivity analyses. Our results support earlier findings in the Atlantic and substantiate the majority of istiophorid billfish survive when released from recreational and longline ishing gear, clearly implying catch-and-release as a viable management option that permits ishing activity while protecting parental biomass and the fishery. Une meta-analyse (inverse de la variance avec modele a effets aleatoires) de 46 etudes a ete utilisee pour estimer la taille des effets de la mortalite apres remise a l'eau ([F.sub.r]) chez six especes d'istiophorides (makaire noir (Istiompax indica), makaire bleu (Makaira nigricans), makaire becune (Tetrapturus pfluegeri), espadon voilier (Istiophorus platypterus), marlin raye (Kajikia audax)et makaire blanc (Kajikia albida)) apres leur liberation d'engins de peche sportive, a la palangre ou au harpon. Les etudes comptaient 400 etiquettes de collecte de donnees par satellite detachables et 64 etiquettes acoustiques (ultrasoniques). Bien que les poissons aient ete captures, marques et relaches dans des conditions et emplacements tres varies et avec un eventail d'engins, [F.sub.r] etait homogene parmi les especes. La variabilite de [F.sub.r] etait principalement due a l'erreur d'echantillonnage aleatoire dans les differentes etudes, sans motif evident. Quinze etudes (33% des etiquettes) n'indiquaient aucune mortalite et la taille sommaire globale des effets pour [F.sub.r] etait de 13,5% (IC 95% : 10,3%-17,6%). Puisque le modele a effets aleatoires se decomposait en un modele a effets fixes quand la variance entre etudes etait [T.sup.2] = 0,00, les resultats ont ete confirmes a l'aide de tests inferentiels non parametriques exacts et d'analyses de la sensibilite. Nos resultats appuient des resultats anterieurs pour l'Atlantique et revelent que la majorite des istiophorides survivent quand ils sont relaches d'engins de peche sportive ou a la palangre, ce qui indique clairement que la peche avec remise a l'eau est une option de gestion valable qui permet l'activite de peche tout en protegeant la biomasse parentale et la ressource. [Traduit par la Redaction], Introduction Mortality is one of the key parameters needed for modelling the population dynamics of any species. Changes in mortality can result in changes in population growth (Ricker 1975; Quinn [...]

Abstract--Analyses of sex-specific yield per recruit and spawning stock biomass per recruit were conducted to evaluate the current status of the sailfish (Istiophorus platypterus) fishery in the waters off eastern [...]

Abstract--Age and growth of sailfish (Istiophorus platypterus) in waters off eastern Taiwan were examined from counts of growth rings on cross sections of the fourth spine of the first dorsal [...]

Greater amberjack (Seriola dumerili) is an important fishery resource with a circumglobal distribution from tropical to temperate waters. Here, we investigated the spawning migration and habitat utilization of S. dumerili in the East China Sea (ECS). Archival tags were attached to 22 adult fish to examine their horizontal and vertical movements and estimate the spawning ground. S. dumerili were captured and released in the coastal waters of eastern Taiwan on November of 2016 and 2017. Information from seven pop‐up satellite archival tags and seven depth–temperature recorders was recovered. Almost all of the fish stayed in the Taiwanese exclusive economic zone. Most individuals moved from released site to the southern edge of the ECS and showed behavior associated with the topographic features in winter (November to December). These phenomena may be related to foraging and be driven by oceanographic features such as the seasonal monsoon and the Kuroshio. The fish then migrated to the south offshore area of Taiwan in January and February. During their southward migration, the fish experienced a slowly elevated water temperature regime (SETR), which is one of the environmental factors that induce final oocyte maturation. In the spawning season (February to April), tagged females exhibited continuous diel vertical movements (DVMs) after experiencing the SETR. These continuous DVMs were observed over a wide geographic range from north to south in the Kuroshio off eastern Taiwan. Our study demonstrated that the putative spawning ground of S. dumerili must extend further in a north–south direction than predicted in a previous study. [ABSTRACT FROM AUTHOR]

To learn about the movement patterns of bigeye tuna in eastern Taiwan, pop-up satellite archival tags were attached on five tuna ~55 kg and prematurely detached and popped-up after 32 to 132 days-at-liberty. Two tags were physically recovered and provided fine-scale data archiving the full 47 and 132 days-at-liberty. The deepest descent recorded was 1,292 m and the coldest temperature visited 2.7°C. During daytime, the fish spent the majority of time above 400 m at temperatures from ~10 - 25°C and at nighttime; residency was largely confined to the mixed-layer from the surface to ~100 m. Vertical movements traversing through the thermocline during the daytime are based on physiological constraints and/or rapid directional changes conducive for optimal search strategies that increases the chances of prey encounters. Bigeye tuna appear to follow the diel vertical movements of prey organisms comprising the deep sound scattering layer to exploit them as a resource. [ABSTRACT FROM AUTHOR]

Blue marlin are sexually dimorphic in size-at-age and other biological characteristics. However, few studies have examined the possible impact of sexual dimorphism on the population parameters and the ratios of fishing to total mortality (the exploitation ratios) for this species. We analyzed sex-specific catch-at-length data for blue marlin collected from the Taiwanese tuna longline fishery in the northwest Pacific Ocean, ranging between 100–311 cm in eye to fork length (EFL) for females and 100–236 cm EFL for males, and show that the proportion of females in the catch (the sex ratio) increases with length, with females reaching larger body sizes than males. Minor differences in fishery sex ratios among months were observed. Growth parameters, length structures, and natural mortality rates were estimated to differ between males and females, while fishing mortality rates were found to be similar. Nevertheless, the exploitation ratio for females was higher than that for males. We suggest that growth parameters and natural mortality rates should be sex-specific when assessments for sexually-dimorphic species such as blue marlin are conducted, and that management of blue marlin fisheries could be developed based on size limit regulations for large individuals. [ABSTRACT FROM AUTHOR]