Reconstructing ecosystem dynamics in the central Pacific Ocean, 1952–1998. II. A preliminary assessment of the trophic impacts of fishing and effects on tuna dynamics

2002 ◽  
Vol 59 (11) ◽  
pp. 1736-1747 ◽  
Author(s):  
Sean P Cox ◽  
Timothy E Essington ◽  
James F Kitchell ◽  
Steven J.D. Martell ◽  
Carl J Walters ◽  
...  

Pelagic fisheries in the Pacific Ocean target both large (Thunnus spp.) and small tunas (juveniles of Thunnus spp; Katsuwonus pelamis) but also take billfishes (Xiphias gladius, Makaira spp., Tetrapturus spp., Istiophorus platypterus) and sharks (Prionace glauca, Alopias superciliosus, Isurus oxyrinchus, Carcharhinus longimanus, Galeocerdo cuvieri) as bycatch. We developed a multispecies model using the Ecopath with Ecosim software that incorporated time-series estimates of biomass, fishing mortality, and bycatch rates (1952–1998) to evaluate the relative contributions of fishing and trophic impacts on tuna dynamics in the central Pacific (0°N to 40°N and 130°E to 150°W). The Ecosim model reproduced the observed trends in abundance indices and biomass estimates for most large tunas and billfishes. A decline in predation mortality owing to depletion of large predators was greatest for small yellowfin tuna and could possibly account for apparent increases in biomass. For other tunas, however, predicted changes in predation mortality rates were small (small bigeye) or were overwhelmed by much larger increases in fishing mortality (skipjack and small albacore). Limited evidence of trophic impacts associated with declining apex predator abundance likely results from the difficulties of applying detailed trophic models to open ocean systems in which ecological and fishery data uncertainties are large.

2003 ◽  
Vol 54 (4) ◽  
pp. 463 ◽  
Author(s):  
Wade Whitelaw

Gamefishing is a developing industry for many of the Pacific Island nations, with a number of countries encouraging the industry with tax relief and tourism promotion. This paper was prepared to provide a preliminary appraisal of gamefish facilities and recreational billfish catches of Pacific Island countries in the Western and Central Pacific Ocean. The level of development of gamefishing varies among Pacific Island nations, with fishers of some countries only carrying out subsistence fishing (including billfish), whereas others have a well-developed gamefishing infrastructure. The gamefish facilities of each country are described, including charter operations, number of private vessels and berthing facilities. Estimates of recreationally caught billfish are also provided for each Pacific Island nation. These estimates have been facilitated by the development of a gamefish catch and effort database by the Secretariat of the Pacific Community. Presently, an estimated 1050 metric tonnes of marlin are caught by gamefishing in the Western and Central Pacific Ocean, which compares with an estimate of around 18 000 metric tonnes caught by commercial longline and purse seine vessels.


2007 ◽  
Vol 22 (1) ◽  
pp. 125-142 ◽  
Author(s):  
Transform Aqorau

AbstractThe 2000 Convention for the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific Ocean (WCPF Convention) establishes a Commission which will be responsible for setting catch limits and effort controls for the fishery. The Convention will require the Pacific Island States to impose some form of catch limits and this presents them with the opportunity to explore ways to enhance the fisheries regimes they manage. This paper explores the legal issues surrounding a possible rights-based regime, both as a collective approach by the Pacific Island States, and individually. The paper suggests possible legal approaches to the introduction of a rights-based fisheries management regime, drawing on ways in which they may structure their fisheries legislation, and on experiences from other regions. The paper concludes by examining the implications for the Pacific Island States of such an approach.


2011 ◽  
Vol 24 (19) ◽  
pp. 5192-5194 ◽  
Author(s):  
S. M. Penny ◽  
G. H. Roe ◽  
D. S. Battisti

Penny et al. recently showed that the midwinter suppression in storminess over the western and central Pacific Ocean is due to a reduction in the number and amplitude of “seed” disturbances entering the Pacific storm track from midlatitude Asia. In this reply, the authors strengthen the conclusions that were originally put forth and show that the apparent departure from this behavior presented in a recent comment originates in the commenters having undersampled the full dataset of interannual variability. It is shown that when the Pacific storm track is only weakly “seeded” by an upstream source, as is common during winter and uncommon during fall and spring, it is likely to be weaker than average, and this reduction is highly statistically significant and the amplitude compares well with the midwinter suppression.


2015 ◽  
Vol 112 (5) ◽  
pp. 1292-1297 ◽  
Author(s):  
Tristan J. Horner ◽  
Helen M. Williams ◽  
James R. Hein ◽  
Mak A. Saito ◽  
Kevin W. Burton ◽  
...  

Biological carbon fixation is limited by the supply of Fe in vast regions of the global ocean. Dissolved Fe in seawater is primarily sourced from continental mineral dust, submarine hydrothermalism, and sediment dissolution along continental margins. However, the relative contributions of these three sources to the Fe budget of the open ocean remains contentious. By exploiting the Fe stable isotopic fingerprints of these sources, it is possible to trace distinct Fe pools through marine environments, and through time using sedimentary records. We present a reconstruction of deep-sea Fe isotopic compositions from a Pacific Fe−Mn crust spanning the past 76 My. We find that there have been large and systematic changes in the Fe isotopic composition of seawater over the Cenozoic that reflect the influence of several, distinct Fe sources to the central Pacific Ocean. Given that deeply sourced Fe from hydrothermalism and marginal sediment dissolution exhibit the largest Fe isotopic variations in modern oceanic settings, the record requires that these deep Fe sources have exerted a major control over the Fe inventory of the Pacific for the past 76 My. The persistence of deeply sourced Fe in the Pacific Ocean illustrates that multiple sources contribute to the total Fe budget of the ocean and highlights the importance of oceanic circulation in determining if deeply sourced Fe is ever ventilated at the surface.


2010 ◽  
Vol 60 (12) ◽  
pp. 2857-2861 ◽  
Author(s):  
Chuang Chen ◽  
Qiang Zheng ◽  
Ya-Nan Wang ◽  
Xiao-Jun Yan ◽  
Li-Kai Hao ◽  
...  

A Gram reaction-negative, weakly motile, non-spore-forming, rod-shaped, aerobic bacterium designated strain JLT832T was isolated from surface water of the central Pacific Ocean and formed yellow colonies on rich organic (RO) medium. The strain was oxidase-negative and catalase-positive. Acid was produced from mannitol, glucose, sucrose, lactose, sorbitol, maltose, (+)-trehalose and d-fructose. No acid was produced from d-(+)-xylose. The major cellular fatty acids of strain JLT832T were C18 : 1 ω7c, C14 : 0 2-OH and C16 : 0. The major polar lipids were sphingoglycolipid, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. Ubiquinone-10 and spermidine were present as the major quinone and polyamine, respectively. The genomic DNA G+C content of strain JLT832T was 66.0±0.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the new isolate formed a tight branch within the family Sphingomonadaceae but was clearly separate from established genera in this family. The sequence similarities between the new isolate and type strains of established genera ranged from 90.5 to 94.9 %. Based on these data, strain JLT832T constitutes a novel genus and species, for which the name Stakelama pacifica gen. nov., sp. nov. is proposed. The type strain of Stakelama pacifica is JLT832T (=CGMCC 1.7294T =LMG 24686T).


2015 ◽  
Vol 30 (3) ◽  
pp. 477-511 ◽  
Author(s):  
Michel Morin

The tuna fishery of the Western and Central Pacific Ocean occurs for the greater part in waters under the sovereignty or jurisdiction of coastal States which qualify as small island developing States (sids); this fishery is managed by the Western and Central Pacific Fisheries Commission (wcpfc). On account of the majority they represent, the sids strive for the adoption of measures which would benefit them. This article discusses the effect of these measures which may give the impression that the delicate balance reached with the adoption of the losc between the rights of coastal States and other States is being upset; this can be regarded as a kind of ‘creeping jurisdiction’. Three issues are considered: the quasi-exemption of application of many rules by the sids, the issue of the application of the Convention in the various areas under national jurisdiction and the requirements for the exercise of navigational rights.


2021 ◽  
Author(s):  
◽  
Oscar Clark

<p>Palmyra Atoll is an isolated carbonate reef system located approximately 1600 km south of Hawaii in the northern Line Islands, central Pacific Ocean. Sediment samples from the lagoons and tidal zones were analyzed for grainsize and composition, and the results used to compile detailed maps and interpret the environments and lithofacies present. A distinct grainsize distribution was observed forming concentric bands ranging from coarse gravel rubble on the outer reef through to finer material in the interior of the atoll in the deep lagoons, where peloidal muds prevail. Five lithologic facies have been identified and typical sediments are poorly sorted and near-symmetrical in their grainsize distribution. On average, sediments are medium sand. A distinct chlorozoan assemblage was observed with coral and calcareous red algal fragments forming half of the sediment, with varying amounts of molluscs, Halimeda and foraminifera being the lesser major constituents. Lagoonal and tidal sediments showed little variation in composition between locations and lacked clear compositional zonation, characteristic of other larger atolls of the Pacific. Palmyra Atoll is unique in that it has had little human intervention for the last sixty years and as a result uninhibited natural processes are occurring. It is also unique in that it displays relatively deep for its size (<55 m), steep-sided compartmentalized lagoons that have abundant fine material (upward of 70% silt or finer), a feature not commonly observed at other Pacific atolls. This fine material has been identified as a peloidal mud and its mode and rate of deposition may be partly controlled by the abundant zooplankton in the lagoons. Recent sediments of Palmyra Atoll are almost entirely carbonate, originating from reef organisms inhabiting the atoll. The only other material is small amounts of siliceous sponge skeletons.</p>


2021 ◽  
Author(s):  
◽  
Oscar Clark

<p>Palmyra Atoll is an isolated carbonate reef system located approximately 1600 km south of Hawaii in the northern Line Islands, central Pacific Ocean. Sediment samples from the lagoons and tidal zones were analyzed for grainsize and composition, and the results used to compile detailed maps and interpret the environments and lithofacies present. A distinct grainsize distribution was observed forming concentric bands ranging from coarse gravel rubble on the outer reef through to finer material in the interior of the atoll in the deep lagoons, where peloidal muds prevail. Five lithologic facies have been identified and typical sediments are poorly sorted and near-symmetrical in their grainsize distribution. On average, sediments are medium sand. A distinct chlorozoan assemblage was observed with coral and calcareous red algal fragments forming half of the sediment, with varying amounts of molluscs, Halimeda and foraminifera being the lesser major constituents. Lagoonal and tidal sediments showed little variation in composition between locations and lacked clear compositional zonation, characteristic of other larger atolls of the Pacific. Palmyra Atoll is unique in that it has had little human intervention for the last sixty years and as a result uninhibited natural processes are occurring. It is also unique in that it displays relatively deep for its size (<55 m), steep-sided compartmentalized lagoons that have abundant fine material (upward of 70% silt or finer), a feature not commonly observed at other Pacific atolls. This fine material has been identified as a peloidal mud and its mode and rate of deposition may be partly controlled by the abundant zooplankton in the lagoons. Recent sediments of Palmyra Atoll are almost entirely carbonate, originating from reef organisms inhabiting the atoll. The only other material is small amounts of siliceous sponge skeletons.</p>


2017 ◽  
Vol 30 (1) ◽  
pp. 243-264 ◽  
Author(s):  
Hiroyuki Murakami ◽  
Gabriel A. Vecchi ◽  
Thomas L. Delworth ◽  
Andrew T. Wittenberg ◽  
Seth Underwood ◽  
...  

The 2015 hurricane season in the eastern and central Pacific Ocean (EPO and CPO), particularly around Hawaii, was extremely active, including a record number of tropical cyclones (TCs) and the first instance of three simultaneous category-4 hurricanes in the EPO and CPO. A strong El Niño developed during the 2015 boreal summer season and was attributed by some to be the cause of the extreme number of TCs. However, according to a suite of targeted high-resolution model experiments, the extreme 2015 EPO and CPO hurricane season was not primarily induced by the 2015 El Niño tropical Pacific warming, but by warming in the subtropical Pacific Ocean. This warming is not typical of El Niño, but rather of the Pacific meridional mode (PMM) superimposed on long-term anthropogenic warming. Although the likelihood of such an extreme year depends on the phase of natural variability, the coupled GCM projects an increase in the frequency of such extremely active TC years over the next few decades for EPO, CPO, and Hawaii as a result of enhanced subtropical Pacific warming from anthropogenic greenhouse gas forcing.


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