Temporal assessment of shark incidental catch in the Eastern Pacific Ocean

Albacore (Thunnus alalunga) support an economically valuable global fishery, but surprisingly little is known about the population structure of this highly migratory species. Physical tagging data suggest that Albacore from the North and South Pacific Ocean are separate stocks, but results from previous genetic studies did not support this two stock hypothesis. In addition, observed biological differences among juveniles suggest that there may be population substructure in the North Pacific. We used double‐digest restriction site‐associated DNA sequencing to assess population structure among 308 Albacore caught in 12 sample areas across the Pacific Ocean (10 North, 2 South). Since Albacore are highly migratory and spawning areas are unknown, sample groups were not assumed to be equivalent to populations and the genetic data were analyzed iteratively. We tested for putatively adaptive differences among groups and for genetic variation associated with sex. Results indicated that Albacore in the North and South Pacific can be distinguished using 84 putatively adaptive loci, but not using the remaining 12,788 presumed neutral sites. However, two individuals likely represent F1 hybrids between the North and South Pacific populations, and 43 Albacore potentially exhibit lower degrees of mixed ancestry. In addition, four or five cross‐hemisphere migrants were potentially identified. No genetic evidence was found for population substructure within the North Pacific, and no loci appeared to distinguish males from females. Potential functions for the putatively adaptive loci were identified, but an annotated Albacore genome is required for further exploration. Future research should try to locate spawning areas so that life history, demography, and genetic population structure can be linked and spatiotemporal patterns can be investigated.

The population structure of the giant mottled eel, Anguilla marmorata, was investigated with mitochondrial and microsatellite DNA analyses using 449 specimens from 13 localities throughout the species range. Control region F-statistics indicated the North Pacific (Japan, Taiwan, Philippines, Sulawesi), South Pacific (Tahiti, Fiji, New Caledonia, Papua New Guinea), eastern Indian Ocean (Sumatra), western Indian Ocean (Réunion, Madagascar), Ambon, and Guam regions were significantly different (Phi(ST) = 0.131-0.698, P < 0.05) while only a few differences were observed between localities within the South Pacific. These regions were roughly clustered in the neighbour-joining tree, although Ambon individuals were mainly divided into North and South Pacific groups. Analysis with eight microsatellite loci showed almost identical results to those of the control region, except no genetic difference was observed between the western and eastern Indian Ocean (F(ST) = 0.009, P > 0.05). The Bayesian cluster analysis of the microsatellite data detected two genetic groups. One included four North Pacific localities, and the other included eight localities in the South Pacific, Indian Ocean, and Guam, but Ambon individuals were evenly assigned to these two groups. These results showed that A. marmorata has four genetically different populations (North Pacific, South Pacific, Indian Ocean, Guam region). The North Pacific population is fully panmictic whereas the South Pacific and Indian Ocean populations have a metapopulation structure. Interestingly, Guam was suggested to be inhabited by a reproductive population restricted to that region, and the individuals from the North and South Pacific populations co-exist in Ambon.

Zischke, M. T., Griffiths, S. P., Tibbetts, I. R., and Lester, R. J. G. 2013. Stock identification of wahoo (Acanthocybium solandri) in the Pacific and Indian Oceans using morphometrics and parasites. – ICES Journal of Marine Science, 70:164–172. The wahoo (Acanthocybium solandri) is an increasingly important by-product species of tropical pelagic fisheries worldwide. However, specific management of the species is currently hindered by a dearth of information on basic biology and stock structure. This study examined the stock structure of wahoo using morphometric characters and parasite fauna from fish collected in three regions of the western Pacific, and one region in each of the eastern Pacific and eastern Indian Oceans. Similar morphometric measurements and parasite abundance of wahoo collected off eastern Australia suggest they may form part of a single phenotypic stock in the western Pacific Ocean. Morphometric measurements and parasite fauna were significantly different among wahoo from the western Pacific and eastern Pacific Oceans, suggesting multiple discrete phenotypic stocks despite genetic homogeneity. Assessing fish from a range of regions throughout the Pacific Ocean may help discriminate stock boundaries in this region. Future research using complementary techniques, such as otolith microchemistry and genetic microsatellites, may improve our understanding of the global stock structure of wahoo to suitably inform regional fishery management organizations.

We set out to disentangle the impacts of forcing over land vs. forcing over ocean on the sea surface temperature (SST) pattern. Based on previous research showing that forcings over land and ocean have distinct impacts on the circulation, we hypothesize that they would also affect the pattern of sea surface temperatures in different ways. We investigate the research question by quadrupling the CO2 concentration either only over ocean or only over land in the coupled global climate model MPI-ESM-1.2.Our main results are: the climate response to 4 x CO2 forcing only over land surface and forcing only over ocean adds up surprisingly linearly to the climate response to forcing everywhere. 4 x CO2 forcing over land causes a cooling of up to 1.4 K in the equatorial, Eastern, and Southeastern Pacific Ocean within two years.&amp;#160;In contrast, positive forcing over the ocean does not produce such a cooling on any time scale Two main mechanisms contribute to the Pacific cooling in response to positive forcing over land: (a) a northward ITCZ shift originating from the fact that there is more land in the Northern than the Southern hemisphere, enhancing equatorial upwelling and cooling from strengthened trade winds (b) the monsoon-desert mechanism (Rodwell &amp;amp; Hoskins 1996), which strengthens the subtropical highs in response to atmospheric heating over the Americas, increasing the equatorward advection of cold air and initiating a wind-evaporation-SST feedback. &amp;#160;We find an equatorial and Eastern Pacific cooling not only in the abrupt land-forced simulation, but also in a transient simulation forced with a 1% / year CO2 increase over land, on a time scale of 20 years. The surprising finding that a positive forcing can cause a cooling in the Eastern Pacific, along with the mechanisms we describe, may contribute to better understanding the recent cooling of the Eastern Pacific Ocean as well as the long-standing model bias in simulating Eastern Pacific sea surface temperature patterns.

A global comparison of subtropical underwater formation rates

&amp;lt;p&amp;gt;Different types of El Ni&amp;amp;#241;o-Southern Oscillation (ENSO) predictions are sensitive to the initial errors in different key areas in the Pacific Ocean. And it is known that the prediction can be improved by removing the initial errors by using assimilation methods. However yet, few studies have quantified to what extent can different types of ENSO predictions be improved by assimilating variable in different key areas. In Hou et.al (2019), 4 types of ocean temperature initial error patterns were classified for two types of El Ni&amp;amp;#241;o prediction. It was indicated that initial errors in the north Pacific, covering the Victoria Mode region, along with south Pacific, covering the South Pacific Meridional Mode region, and subsurface layer of western equatorial Pacific have strong influence on the ENSO prediction. Following the data analysis method and the initial error patterns they proposed, we assimilate ocean temperature in these three key areas of Pacific Ocean by using CMIP5 pi-control dataset and particle filter method. Most EP- and CP-El Ni&amp;amp;#241;o predictions in December are improved after assimilating the ocean temperature in southeast Pacific, north Pacific and western equatorial Pacific from January to March. Specially, for the prediction ensemble which contains EP(CP)-type-1 initial errors, the EP(CP)-El Ni&amp;amp;#241;o prediction skill raises the most after assimilating the Tropical Pacific temperature, comparing with the result of assimilating the south Pacific and north Pacific. As for the prediction ensemble which contains EP-type-2 initial errors, which present similar pattern to EP-type-1 but with opposite sign, the EP-El Ni&amp;amp;#241;o prediction skill increases the most by assimilating the north Pacific temperature. The results verify that the initial errors in the north Pacific exert contrary influences on the ENSO prediction with that in the southeast Pacific and western tropical Pacific. In addition, the initial errors in the north Pacific is more of concern for the SST prediction in the central tropical Pacific in December, while those in the southeast Pacific and tropical western Pacific is more related to the SST prediction in the central-eastern tropical Pacific. In conclusion, to better predict the types of El Ni&amp;amp;#241;o, attentions should be paid to the initial ocean temperature accuracy not only in the tropical Pacific but also in the north and south Pacific.&amp;amp;#160;&amp;lt;/p&amp;gt;&amp;lt;div&amp;gt; &amp;lt;div&amp;gt; &amp;lt;div&amp;gt;&amp;amp;#160;&amp;lt;/div&amp;gt; &amp;lt;/div&amp;gt; &amp;lt;div&amp;gt;&amp;amp;#160;&amp;lt;/div&amp;gt; &amp;lt;/div&amp;gt;

Formation rates of subtropical underwater in the Pacific Ocean

The thermal condition anomaly of the western Pacific warm pool and its zonal displacement have very important influences on climate change in East Asia and even the whole world. However, the impact of the zonal wind anomaly over the Pacific Ocean on zonal displacement of the warm pool has not yet been analyzed based on long-term record. Therefore, it is important to study the zonal displacement of the warm pool and its response to the zonal wind anomaly over the equatorial Pacific Ocean. Based on the NCDC monthly averaged SST (sea surface temperature) data in 2°×2° grid in the Pacific Ocean from 1950 to 2000, and the NCEP/NCAR global monthly averaged 850 hPa zonal wind data from 1949 to 2000, the relationships between zonal displacements of the western Pacific warm pool and zonal wind anomalies over the tropical Pacific Ocean are analyzed in this paper. The results show that the zonal displacements are closely related to the zonal wind anomalies over the western, central and eastern equatorial Pacific Ocean. Composite analysis indicates that during ENSO events, the warm pool displacement was trigged by the zonal wind anomalies over the western equatorial Pacific Ocean in early stage and the process proceeded under the zonal wind anomalies over the central and eastern equatorial Pacific Ocean unless the wind direction changes. Therefore, in addition to the zonal wind anomaly over the western Pacific, the zonal wind anomalies over the central and eastern Pacific Ocean should be considered also in investigation the dynamical mechanisms of the zonal displacement of the warm pool.

We evaluated the regional distributions of six nitrogen (N 2 )‐fixing bacteria in the North Pacific Ocean using quantitative polymerase chain reaction amplification of planktonic nifH genes. Samples were collected on four oceanographic research cruises between March 2002 and May 2005 that spanned a latitudinal range from 12°S and 54°N between 152°W and 170°W. Samples were collected throughout the upper ocean (&lt;200 m) in the northern regions of the South Pacific Subtropical Gyre (SPSG), equatorial waters, the North Pacific Subtropical Gyre (NPSG), the North Pacific Transitional Zone (NPTZ), and within the Pacific Sub Arctic Gyre (PSAG). There were distinct spatial gradients in concentrations of nutrients, chlorophyll, and the abundances of N 2 ‐fixing bacteria within the various oceanic biomes. In general, nifH ‐containing bacteria were most abundant in the midregions of the NPSG (latitudes between ~14°N and 29°N), where unicellular cyanobacterial phylotypes dominated nifH gene abundances. The abundances of all nifH ‐containing groups declined within the northern and southern regions of NPSG. Although nifH ‐containing groups were detectable in the northern regions of the SPSG, throughout the equatorial waters, and within the NPTZ, gene copy abundances of most groups were lower in these regions than those found the in the NPSG. In the NPSG, surface water abundances of the various nifH phylotypes examined ranged from &lt;50 copies L −1 to ~10 5 nifH copies LS −1 . Overall, the abundances of an uncultivated, presumed unicellular nifH sequence‐type (termed Group A) were the most abundant and widely distributed of the phylotypes examined. Our results indicate that the distributions of N 2 ‐fixing plankton were largely restricted to the subtropical regions of the North and South Pacific Oceans.

Species-level phylogeography and evolutionary history of the hyperdiverse marine gastropod genus Conus

We tested the hypothesis that segregation in wintering areas is associated with population differentiation in a sentinel North Pacific seabird, the rhinoceros auklet (Cerorhinca monocerata). We collected tissue samples for genetic analyses on five breeding colonies in the western Pacific Ocean (Japan) and on 13 colonies in the eastern Pacific Ocean (California to Alaska), and deployed light-level geolocator tags on 12 eastern Pacific colonies to delineate wintering areas. Geolocator tags were deployed previously on one colony in Japan. There was strong genetic differentiation between populations in the eastern vs. western Pacific Ocean, likely due to two factors. First, glaciation over the North Pacific in the late Pleistocene might have forced a southward range shift that historically isolated the eastern and western populations. And second, deep-ocean habitat along the northern continental shelf appears to act as a barrier to movement; abundant on both sides of the North Pacific, the rhinoceros auklet is virtually absent as a breeder in the Aleutian Islands and Bering Sea, and no tagged birds crossed the North Pacific in the non-breeding season. While genetic differentiation was strongest between the eastern vs. western Pacific, there was also extensive differentiation within both regional groups. In pairwise comparisons among the eastern Pacific colonies, the standardized measure of genetic differentiation (FꞌST) was negatively correlated with the extent of spatial overlap in wintering areas. That result supports the hypothesis that segregation in the non-breeding season is linked to genetic structure. Philopatry and a neritic foraging habit probably also contribute to the structuring. Widely distributed, vulnerable to anthropogenic stressors, and exhibiting extensive genetic structure, the rhinoceros auklet is fully indicative of the scope of the conservation challenges posed by seabirds.

We tested the hypothesis that segregation in wintering areas is associated with population differentiation in a sentinel North Pacific seabird, the rhinoceros auklet (Cerorhinca monocerata). We collected tissue samples for genetic analyses on five breeding colonies in the western Pacific Ocean (Japan) and on 13 colonies in the eastern Pacific Ocean (California to Alaska), and deployed light-level geolocator tags on 12 eastern Pacific colonies to delineate wintering areas. Geolocator tags were deployed previously on one colony in Japan. There was strong genetic differentiation between populations in the eastern vs. western Pacific Ocean, likely due to two factors. First, glaciation over the North Pacific in the late Pleistocene might have forced a southward range shift that historically isolated the eastern and western populations. And second, deep-ocean habitat along the northern continental shelf appears to act as a barrier to movement; abundant on both sides of the North Pacific, the rhinoceros auklet is virtually absent as a breeder in the Aleutian Islands and Bering Sea, and no tagged birds crossed the North Pacific in the non-breeding season. While genetic differentiation was strongest between the eastern vs. western Pacific, there was also extensive differentiation within both regional groups. In pairwise comparisons among the eastern Pacific colonies, the standardized measure of genetic differentiation (FꞌST) was negatively correlated with the extent of spatial overlap in wintering areas. That result supports the hypothesis that segregation in the non-breeding season is linked to genetic structure. Philopatry and a neritic foraging habit probably also contribute to the structuring. Widely distributed, vulnerable to anthropogenic stressors, and exhibiting extensive genetic structure, the rhinoceros auklet is fully indicative of the scope of the conservation challenges posed by seabirds.

The lionfish invasion in the Atlantic and Caribbean has proceeded with vigor since their introduction in the 1980s or early 1990s. Lionfish affect recruitment of juvenile fish to reefs due to predation and are found in densities far surpassing that of their native Indo-Pacific. There is concern that the lionfish may become introduced and proliferate (through aquarium releases, transport on floating debris, or passage through the Panama Canal in ship ballast water) in the eastern tropical and north Pacific. This study presents the first known prediction of the potential for establishment of lionfish in the eastern Pacific Ocean. Through computational modeling, we compare and contrast the dynamics of random hypothetical introductions of lionfish into the eastern Pacific and Atlantic Oceans in order to highlight the different potentials for invasion in both basins. Connectivity between discrete regions (precincts) in both the Atlantic and eastern Pacific are examined and settlement densities are calculated to indicate possible locations of establishment of breeding lionfish populations. Our results suggest that lionfish, which are successful invaders in the Atlantic, may not be as successful in the eastern Pacific due to weak mesoscale connectivity which reduces the rapid spread of lionfish larvae.

We investigated basin‐wide distributions of total particulate phosphorus (TPP) and associated biogeochemical parameters in the euphotic zone (EZ) of the subtropical North and South Pacific Ocean. TPP is primarily composed of living microorganisms, and its distribution is likely controlled by nitrogen (N) supply in typical N‐limited Pacific waters as well as phosphorus (P) supply in P‐limited western North Pacific. TPP concentrations showed a vertically uniform distribution (approximately 15 nM) within the EZ at most stations, but at several northern North Pacific stations, TPP peaks (&gt;20 nM) were observed in the lower EZ where nitrate and nitrite concentrations were high. Relationships between TPP and biogeochemical parameters indicate that a possible factor controlling TPP in the upper EZ was dinitrogen fixation and that in the lower EZ was shoaling of the nitracline. Geographical distribution of TPP was relatively uniform compared to that of phosphate, which varied from &lt;10 nM in the western North Pacific to &gt;100 nM in the eastern North and South Pacific. The western North Pacific was a domain characterized by lower dissolved organic P (DOP) concentrations, higher alkaline phosphatase activities, and higher particulate polyphosphate (PpolyP):TPP ratios compared to other domains. These characteristics indicated that active DOP utilization and PpolyP accumulation could play important roles in the maintenance of TPP stocks as alternatives to phosphate utilization in this distinctive domain. Our results demonstrated that TPP distributions were vertically and geographically uniform across the subtropical Pacific Ocean, concealing that TPP stocks were likely underpinned by a range of nutrient supply mechanisms.

Shortwave radiation (SWR) is having direct impact on sea surface temperature (SST). In this paper the relation between SWR and SST has been over east and west Pacific Ocean. TAO/TRITON buoy data have been used for this study. It is well known that El Nino phenomenon is related to SST anomalies and warmer temperatures can observe over eastern Pacific Ocean (EP) leading to strong El Nino. The relation between eastern and western Pacific Ocean (WP) SST, SWR has been checked and presented. Monthly data have been used to find out the relation and the annual variation of SWR and SST during the El Nino and La Nina events are discussed.