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 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 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 Target strength of skipjack tuna (Katsuwanus pelamis) associated with fish aggregating devices (FADs)

2018 ◽  
Vol 75 (5) ◽  
pp. 1790-1802 ◽  
Author(s):  
Guillermo Boyra ◽  
Gala Moreno ◽  
Bea Sobradillo ◽  
Isabel Pérez-Arjona ◽  
Igor Sancristobal ◽  
...  
Keyword(s):  
Fork Length ◽  
Acoustic Properties ◽  
Target Strength ◽  
Skipjack Tuna ◽  
Method Of Least Squares ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Fish Morphology ◽  
Ocean Measurements ◽  
Fish Aggregating Devices

Abstract This paper presents measures of target strength (TS; dB re 1 m2) and models of TS vs. fork length (L; cm), i.e. TS=20logL+b20, for skipjack tuna associated with fish aggregating devices (FADs) in the Central Pacific Ocean. Measurements were made using 38-, 120-, and 200-kHz split-beam echosounders on a purse-seine workboat during fishing operations. To mitigate potential bias due to unresolved targets, TS measurements were rejected if they were not simultaneously detected with multiple echosounder frequencies in approximately the same location. The filtered TS and concomitantly sampled L data were used to estimate b20 = −76, −71, and −70.5 dB for 38, 120, and 200 kHz, respectively, using the method of least squares. For comparison, quasi-independent estimates of TS and b20 were calculated from acoustic echo-integration and catch data representing entire aggregations around the FADs. The results differed by ≤1 dB for all three frequencies. The sensitivities of these results to variations in fish morphology and behaviour were explored using a simulation of TS for fish without swimbladders. The utility of the results on acoustic properties of skipjack tuna and next research steps to achieve selective fishing at FADs are discussed.

Reproductive biology of male skipjack tuna Katsuwonus pelamis (Linnaeus) in the tropical western and central Pacific Ocean

2010 ◽  
Vol 76 (5) ◽  
pp. 785-793 ◽  
Author(s):  
Hiroshi Ashida ◽  
Toshiyuki Tanabe ◽  
Keisuke Satoh ◽  
Atsushi Fukui ◽  
Sho Tanaka ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Reproductive Biology ◽  
Skipjack Tuna ◽  
Central Pacific ◽  
Katsuwonus Pelamis ◽  
Central Pacific Ocean
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