The U.S. North Pacific Region

This chapter describes the North Pacific region and the major issues facing this marine fisheries ecosystem, and presents some summary statistics related to the 90 indicators of ecosystem-based fisheries management (EBFM) criteria. The North Pacific contains the fifth-highest number of managed taxa, including commercially and recreationally important groundfish (e.g., walleye pollock, Pacific cod, sablefish, lingcod, halibut, rockfishes, yellowfin sole), cephalopods, king-and Tanner crabs, salmon, and steelhead. The North Pacific ecosystem has biota and marine communities that are responding to the consequences of fishing pressure, climate oscillations, and other ocean uses. More recent stressors, including substantial regional warming, associated species shifts, increasing human population density, and proliferation of invasive species are affecting this system and altering its composition, dynamics, and LMR production. Overall, a moderate to high degree of EBFM progress has been made in the eastern Bering Sea, Aleutian Islands, and Gulf of Alaska in terms of implementation, advancing knowledge of ecosystem principles, examining trade-offs, assessing risks and vulnerabilities, and in beginning to establish and use ecosystem-level reference points for management. While much information has been obtained and applied toward ecosystem-level calculations, syntheses, and models, continued progress in applying these system-wide emergent properties into regional management frameworks remains necessary.

The “Cribrilina annulata" problem and new species of Juxtacribrilina (Bryozoa: Cheilostomata: Cribrilinidae) from the North Pacific

Originally described from Greenland, Juxtacribrilina annulata (Fabricius, 1780) (previously known as Cribrilina annulata) has long been regarded as having a circumpolar, Arctic-boreal distribution. The genus Juxtacribrilina Yang, Seo, Min, Grischenko & Gordon, 2018 accommodated J. annulata and three related North Pacific species formerly in Cribrilina Gray, 1848 that lack avicularia, have a reduced (hood-like, cap-like, or vestigial) ooecium closely associated with modified latero-oral spines to form an ooecial complex, and produce frontally or marginally positioned dwarf ovicellate zooids. While the recently described NW Pacific species J. mutabilis and J. flavomaris, which have a vestigial ooecium like a short, flattened spine, clearly differ from J. annulata, the differences between J. annulata and other Pacific populations remained unclear. Here we provide descriptions for five species from the North Pacific region. We identified a specimen from the Sea of Okhotsk as J. annulata. Among the other four species, J. ezoensis n. sp. has a trans-Pacific distribution (abundant at Akkeshi, Hokkaido, Japan; also detected in the Commander Islands and at Ketchikan, Southeast Alaska); J. pushkini n. sp. was found only at Ketchikan; J. dobrovolskii n. sp. was found only at Shikotan Island in the Lesser Kuril Chain; and J. tumida n. sp. was found only at Kodiak, Gulf of Alaska. These four species all differ from J. annulata in having one or two frontal pore chambers on the proximal gymnocyst of most zooids; in budding frontal dwarf ovicellate zooids from these chambers rather than from basal pore chambers; in producing dwarf zooids more abundantly; and in having ooecia that are somewhat to markedly more reduced (cap-like rather than hood-like) and more closely integrated with the modified latero-oral spines. Furthermore, in the Pacific species, the ooecium in basal zooids arises from the roof of the distal pore chamber of the maternal zooid; ovicellate zooids can thus also bud a distal autozooid and are often arranged in columnar series with other zooids. In J. annulata, the hood-like kenozooidal ooecium budded from the maternal zooid replaces the distal autozooid, and ovicellate zooids are thus usually not embedded in a columnar series.

The Effect of Mesoscale Eddy on the Characteristic of Sound Propagation

A mesoscale eddy is detected and tracked in the western North Pacific region. Within the life cycle of the cyclonic eddies, the intensities of eddies make a difference. Satellite images indicate the oceanic eddy keeps westward-moving until it disappears. Oceanographic and acoustic characteristics of the eddy are studied. The acoustic energy distribution results from the different intensity of both modelled eddy and measured eddy are calculated. With sound propagation through the cyclonic eddy and anticyclonic eddy, the position of convergence zone moves away from and towards the acoustic source compared with the sound propagation through background hydrography. The coupling coefficient of different orders of normal modes changes significantly. The closer to the centre of the eddy, the stronger the coupling coefficient.

Statistical Prediction of Typhoon-Induced Rainfall over China Using Historical Rainfall, Tracks, and Intensity of Typhoon in the Western North Pacific

Typhoons or mature tropical cyclones (TCs) can affect inland areas of up to hundreds of kilometers with heavy rains and strong winds, along with landslides causing numerous casualties and property damage due to concentrated precipitation over short time periods. To reduce these damages, it is necessary to accurately predict the rainfall induced by TCs in the western North Pacific Region. However, despite dramatic advances in observation and numerical modeling, the accuracy of prediction of typhoon-induced rainfall and spatial distribution remains limited. The present study offers a statistical approach to predicting the accumulated rainfall associated with typhoons based on a historical storm track and intensity data along with observed rainfall data for 55 typhoons affecting the southeastern coastal areas of China from 1961 to 2017. This approach is shown to provide an average root mean square error of 51.2 mm across 75 meteorological stations in the southeast coastal area of China (ranging from 15.8 to 87.3 mm). Moreover, the error is less than 70 mm for most stations, and significantly lower in the three verification cases, thus demonstrating the feasibility of this approach. Furthermore, the use of fuzzy C-means clustering, ensemble averaging, and corrections to typhoon intensities, can provide more accurate rainfall predictions from the method applied herein, thus allowing for improvements to disaster preparedness and emergency response.

A climatological study of typhoons over the Philippine Area of Responsibility from 1989–2018

The Philippines is in the Western North Pacific region, where it is a recipient of several weather disturbances such as tropical cyclones. This study aims to determine trends and periodicities of typhoons (TY) within the Philippine Area of Responsibility (PAR), and the rainfall they brought in a 30-year period (1989–2018) for future forecast and disaster risk mitigation efforts of these TY. These TYs are raised when TC’s sustained winds are 118 kph and above. Frequency analysis of TY is done to determine the trends and periodicities in terms of the yearly total occurrence, number of TY that made landfall, distribution of TY classification, and their seasonal variation. The results showed that with PAR the yearly total occurrence of TY seems to have an approximately 12-year periodicity where maximum occurrence was observed around the years 1994, 2004, and 2014 while minimum occurrence was observed in years 1989, 1999, and 2010. Also, track data shows that only 32 % of these TY made a landfall within PAR. Out of the three regions in the Philippines, Luzon Island is the region where most of the severe typhoons made landfall at 80 %. Moreover, TYs occurred mostly during September to November where the transition period between the northeast monsoon and south west monsoon usually occurs. Also, rainfall during which these TYs have occurred were obtained from five synoptic stations across the Philippines. It showed from 1989 to 1998, the total yearly rainfall brought by these TYs ranged from 804 mm to 1 912 mm. But from 1999 to 2018, these TYs brought more rain where their total yearly rainfall ranged from 2 844 mm to 4 941 mm.

Reconstruction holocene environmental changes in North-Western Pacific in relation to paleorecord from Shikotan Island

Results of a paleolimnological investigated of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP warm and humid period corresponding to middle Holocene optimum took place. Cooling thereafter corresponds to Neoglacial. A reconstructed from ca 0.9 to ca 0.58 cal ka BP warm period can be correlated to a Medieval Warm Period. Cooling after 0.58 cal ka BP can be correlated with the LIA. Marine regression stages were identified at ca 6.2-5.9, 5.5-5.1 and 1.07-0.36 cal ka BP. The general chronology of major climatic events of Holocene in the island is in accordance with the climate records from the North Pacific region. Revealed spatial differences in timing and magnitude of the Late Holocene climatic episodes (LIA, MWP) within region needs further investigations.