scholarly journals Biology and Environmental Preferences of Wahoo, Acanthocybium solandri (Cuvier, 1832), in the Western and Central Pacific Ocean (WCPO)

2020 ◽  
Vol 8 (3) ◽  
pp. 184 ◽  
Author(s):  
Chunxia Gao ◽  
Siquan Tian ◽  
Richard Kindong ◽  
Xiaojie Dai
Keyword(s):  
Life History ◽  
Pacific Ocean ◽  
Gonadosomatic Index ◽  
Fork Length ◽  
Current Data ◽  
Central Pacific ◽  
Environmental Preferences ◽  
Central Pacific Ocean ◽  
Swimming Depth ◽  
Data Limitations

Wahoo Acanthocybium solandri is a common bycatch pelagic species in oceanic fisheries targeting tuna and tuna-like species. Biology and environmental preferences are important parameters in understanding life history of fish species including wahoo. Despite the socio-economic importance of wahoo in many coastal countries, little is known about their biological and fisheries information in the Western and Central Pacific Ocean (WCPO). These parameters were analyzed on the basis of samples collected via the Chinese tuna long-line Fishery Observer Programme in 2012. Results obtained from this study show that the fork length (FL) of wahoo ranged from 59 to 169 cm with an average of 111.3 cm, and two dominant size groups were identified at 100 to 130 cm for males and 90 to 130 cm for females. Body size did not significantly differ between female and male wahoo specimens. Wahoo specimens expressed a positive allometric growth (b = 3.183), and the sex ratio was 1.9:1 (female/male), which differed significantly between both sexes. Only female wahoo were observed in catches of FL > 150 cm. The estimated lengths at 50% maturity (FL50) of female and male wahoo were 84 cm and 83 cm, respectively. Gonadosomatic index (GSI) of wahoo was at its peak in November, and on the basis of the stomach content analysis, wahoo mainly preyed on fish (84.64%), cephalopods (14.26%), and crustaceans (1.1%), found on the basis of prey number. The optimal swimming depth and water temperature of wahoo in the WCPO were found to range between 70 and 110 m and 23.1 and 24 °C, respectively. The updated life history information presented in this work helps to address current data limitations and provides critical information for future assessments of wahoo stocks in the WCPO.

scholarly journals A Bayesian Multilevel Ordinal Regression Model for Fish Maturity Data: Difference in Maturity Ogives of Skipjack Tuna (Katsuwonus pelamis) Between Schools in the Western and Central Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Jie Cao ◽  
Xuefang Wang ◽  
Matthew D. Damiano ◽  
Cheng Zhou ◽  
Jiangfeng Zhu
Keyword(s):  
Pacific Ocean ◽  
Ordinal Data ◽  
Gonadosomatic Index ◽  
Fork Length ◽  
Ordinal Regression ◽  
Maturity Stage ◽  
Skipjack Tuna ◽  
Central Pacific ◽  
Free Swimming ◽  
Central Pacific Ocean

The maturity ogive is vital to defining the fraction of a population capable of reproduction. In this study, we proposed a novel approach, a Bayesian multilevel ordinal regression (i.e., Bayesian continuation ratio model), to model the maturity ogive. The model assumes that the observed maturity stage originates from the categorization of latent continuous variables. We demonstrated this approach by testing whether there are differences in the maturity ogive of skipjack tuna (Katsuonus pelamis) in the western and central Pacific Ocean between two school types, i.e., free-swimming and floating-object-associated schools. The model results show that K. pelamis, given the same fork length, are more likely to have a higher maturity stage in a free-swimming school than those associated with floating objects. The gonadosomatic index revealed the same conclusion. Our results indicate that fish aggregation devices (FADs) could negatively affect the maturity of K. pelamis and consequently reduce the population reproductive potential. This study provides (1) an alternative approach to analyze fisheries ordinal data; (2) important quantitative evidence to evaluate the existing ecological hypotheses; and (3) implications for tuna fisheries management.

scholarly journals Combining Weight-Length Relationships and condition factors to estimate the population structure for Skipjack tuna in the Western and Central Pacific Ocean

2014 ◽  
Author(s):  
Shaofei Jin ◽  
Xiaodong Yan ◽  
Heng Zhang ◽  
Wei Fan
Keyword(s):  
Population Structure ◽  
Pacific Ocean ◽  
Fork Length ◽  
Skipjack Tuna ◽  
Growth Phases ◽  
Central Pacific ◽  
Katsuwonus Pelamis ◽  
Central Pacific Ocean ◽  
Length Relationship ◽  
June July

The arguments between Weight-Length Relationship (WLR) and Condition Factor (K) have been lasted since the day they occurred. This paper described WLRs and Ks of Skipjack tuna (Katsuwonus pelamis) samples in Purse Seine fisheries from three cruises (August-September cruise (A-S) in 2009, November-December cruise (N-D) in 2012, and June-July cruise (J-J) in 2013) in the Central and Western Pacific Ocean (CWPO). The results showed that fork length of more than 70% of specimen was below 60 cm (76% in A-S, 87% in N-D, and 73% in J-J). b values of WLRs in class of fork length > 60cm were below 3 significantly (P = 0.062), while b values when fork length < 60 cm were > 3 significantly (P = 0.028). Moreover, K values in different fork length classes for each cruises had one turning point: 60-65cm for J-J, 60-65cm for N-D, and 55-60cm for A-S, and K values were still significantly larger than those of fork length < 40cm (P = 0.06). However, b values at larger fishes were significantly smaller than those of fork length <40cm. We suggest to combine WLRs and K values at different growth phases for evaluating population structure for skipjack tuna.

scholarly journals Combining Weight-Length Relationships and condition factors to estimate the population structure for Skipjack tuna in the Western and Central Pacific Ocean

2014 ◽  
Author(s):  
Shaofei Jin ◽  
Xiaodong Yan ◽  
Heng Zhang ◽  
Wei Fan
Keyword(s):  
Population Structure ◽  
Pacific Ocean ◽  
Fork Length ◽  
Skipjack Tuna ◽  
Growth Phases ◽  
Central Pacific ◽  
Katsuwonus Pelamis ◽  
Central Pacific Ocean ◽  
Length Relationship ◽  
June July

The arguments between Weight-Length Relationship (WLR) and Condition Factor (K) have been lasted since the day they occurred. This paper described WLRs and Ks of Skipjack tuna (Katsuwonus pelamis) samples in Purse Seine fisheries from three cruises (August-September cruise (A-S) in 2009, November-December cruise (N-D) in 2012, and June-July cruise (J-J) in 2013) in the Central and Western Pacific Ocean (CWPO). The results showed that fork length of more than 70% of specimen was below 60 cm (76% in A-S, 87% in N-D, and 73% in J-J). b values of WLRs in class of fork length > 60cm were below 3 significantly (P = 0.062), while b values when fork length < 60 cm were > 3 significantly (P = 0.028). Moreover, K values in different fork length classes for each cruises had one turning point: 60-65cm for J-J, 60-65cm for N-D, and 55-60cm for A-S, and K values were still significantly larger than those of fork length < 40cm (P = 0.06). However, b values at larger fishes were significantly smaller than those of fork length <40cm. We suggest to combine WLRs and K values at different growth phases for evaluating population structure for skipjack tuna.

scholarly journals Primary Production in the Water Column as Major Structuring Element of the Biogeographical Distribution and Function of Archaea in Deep-Sea Sediments of the Central Pacific Ocean

Archaea ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Franziska Wemheuer ◽  
Avril Jean Elisabeth von Hoyningen-Huene ◽  
Marion Pohlner ◽  
Julius Degenhardt ◽  
Bert Engelen ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Primary Production ◽  
Deep Sea ◽  
Archaeal Community ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Deep Sea Sediments ◽  
And Function ◽  
Functional Profiles ◽  
Archaeal Communities

Information on environmental conditions shaping archaeal communities thriving at the seafloor of the central Pacific Ocean is limited. The present study was conducted to investigate the diversity, composition, and function of both entire and potentially active archaeal communities within Pacific deep-sea sediments. For this purpose, sediment samples were taken along the 180° meridian of the central Pacific Ocean. Community composition and diversity were assessed by Illumina tag sequencing targeting archaeal 16S rRNA genes and transcripts. Archaeal communities were dominated by CandidatusNitrosopumilus(Thaumarchaeota) and other members of theNitrosopumilaceae(Thaumarchaeota), but higher relative abundances of the Marine Group II (Euryarchaeota) were observed in the active compared to the entire archaeal community. The composition of the entire and the active archaeal communities was strongly linked to primary production (chlorophyll content), explaining more than 40% of the variance. Furthermore, we found a strong correlation of the entire archaeal community composition to latitude and silicic acid content, while the active community was significantly correlated with primary production and ferric oxide content. We predicted functional profiles from 16S rRNA data to assess archaeal community functions. Latitude was significantly correlated with functional profiles of the entire community, whereas those of the active community were significantly correlated with nitrate and chlorophyll content. The results of the present study provide first insights into benthic archaeal communities in the Pacific Ocean and environmental conditions shaping their diversity, distribution, and function. Additionally, they might serve as a template for further studies investigating archaea colonizing deep-sea sediments.

The Birds of Fanning Island, Central Pacific Ocean

The Condor ◽  
1925 ◽  
Vol 27 (5) ◽  
pp. 185-196 ◽  
Author(s):  
Harold Kirby,
Keyword(s):  
Pacific Ocean ◽  
Central Pacific ◽  
Central Pacific Ocean

scholarly journals The Relationship between Equatorial Mixed Rossby–Gravity and Eastward Inertio-Gravity Waves. Part II

2016 ◽  
Vol 73 (5) ◽  
pp. 2147-2163 ◽  
Author(s):  
Juliana Dias ◽  
George N. Kiladis
Keyword(s):  
Pacific Ocean ◽  
Gravity Waves ◽  
Companion Paper ◽  
Empirical Orthogonal Functions ◽  
Central Pacific ◽  
The West ◽  
Orthogonal Functions ◽  
Central Pacific Ocean ◽  
The Relationship ◽  
Zonal Propagation

Abstract Space–time spectral analysis of tropical cloudiness data shows strong evidence that convectively coupled n = 0 mixed Rossby–gravity waves (MRGs) and eastward inertio-gravity waves (EIGs) occur primarily within the western/central Pacific Ocean. Spectral filtering also shows that MRG and EIG cloudiness patterns are antisymmetric with respect to the equator, and they propagate coherently toward the west and east, respectively, with periods between 3 and 5 days, in agreement with Matsuno’s linear shallow-water theory. In contrast to the spectral approach, in a companion paper it has been shown that empirical orthogonal functions (EOFs) of 2–6-day-filtered cloudiness data within the tropical Pacific Ocean also suggest an antisymmetric pattern, but with the leading EOFs implying a zonally standing but poleward-propagating oscillation, along with the associated tropospheric flow moving to the west. In the present paper, these two views are reconciled by applying an independent approach based on a tracking method to assess tropical convection organization. It is shown that, on average, two-thirds of MRG and EIG events develop independently of one another, and one-third of the events overlap in space and time. This analysis also verifies that MRG and EIG cloudiness fields tend to propagate meridionally away from the equator. It is demonstrated that the lack of zonal propagation implied from the EOF analysis is likely due to the interference between eastward- and westward-propagating disturbances. In addition, it is shown that the westward-propagating circulation associated with the leading EOF is consistent with the expected theoretical behavior of an interference between MRGs and EIGs.

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