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Yu T.,Shanghai Ocean University | Yu T.,CAS Qingdao Institute of Oceanology | Yu T.,Nanjing University of Information Science and Technology | Yu T.,Chinese Academy of Sciences | And 12 more authors.
International Journal of Remote Sensing | Year: 2014

From TOPEX/Poseidon data, the significant uncertainty in global air-sea carbon dioxide (CO2) flux in 2000 is calculated from 21 wind-speed-dependent and 5 sea-state-dependent CO2 transfer velocities and the sea-to-air partial pressure difference proposed by Takahashi, Sutherland, and Kozyr (2010). The sea-state-dependent parameterizations are calculated based on the significant wave height (SWH) and the radar backscatter coefficient measured using the Ku-band altimeter. Uncertainty in air-sea CO2 flux is compared using 26 various transfer velocity formulas. The maximum differences in global monthly mean and 4° zonal mean values for gas transfer velocity among these formulas are 33.20 and 108.20 cm hour-1, respectively. The corresponding differences for sea-to-air CO2 flux are 6.41 and 0.58 Pg C year-1, respectively. Monthly mean global maps of gas transfer velocity and flux are also presented. The average value of the global mean, transfer velocity obtained using the 26 formula is 27.33 ± 9.75 cm hour-1, and the averaged total global net air-to-sea CO2 flux is 2.77 ± 1.02 Pg C year-1 after area weighting and Schmidt number correction. The sea-state-dependent parameterizations are near these values, providing a successful method to estimate the air-sea CO2 transfer velocity and flux. © 2014 © 2014 Taylor & Francis.

Liu B.,Shanghai Ocean University | Liu B.,The Key Laboratory of Sustainable Exploitation of Oceanic Fisheries Resources | Liu B.,University of Maine, United States | Liu B.,Collaborative Innovation Center for National Distant Water Fisheries | And 5 more authors.
Fisheries Research | Year: 2015

We explored an approach to using morphological variables of suqid body and beaks to identify different geographic populations for Dosidicus gigas. We tested this approach using a total of seventeen morphological variables of body and beaks measured for 1490 squids sampled outside the exclusive economic zone (EEZ) waters off Ecuador, Peru and Chile. Linear regression analysis showed significant and positive relationships between beak morphometric variables and mantle lengths. All measured beak variables were significantly different among the three regions (p<. 0.001), with samples from the areas off Chile and Ecuador having the largest and smallest beaks, respectively. The morphometrics of squid beaks showed a significant sexual dimorphism and were useful for sex determination (p<. 0.001), although considerable overlaps were found in the scatter-plots. Hard structure (i.e., beaks) variables were shown more effective than soft body in population discrimination, although a stepwise discriminant analysis (SDA) suggested that both the body and beak morphometric variables are useful for the geographic population discrimination. We found that the standardized beak and body variables are more effective in separating D. gigas potentially geographic populations than the original variables. © 2014 Elsevier B.V.

Lin D.,Shanghai Ocean University | Lin D.,Collaborative Innovation Center for National Distant water Fisheries | Chen X.,Shanghai Ocean University | Chen X.,Collaborative Innovation Center for National Distant water Fisheries | And 6 more authors.
Invertebrate Biology | Year: 2015

Energy investment in reproduction and somatic growth was investigated for summer spawners of the Argentinean shortfin squid Illex argentinus in the southwest Atlantic Ocean. Sampled squids were examined for morphometry and intensity of feeding behavior associated with reproductive maturation. Residuals generated from length-weight relationships were analyzed to determine patterns of energy allocation between somatic and reproductive growth. Both females and males showed similar rates of increase for eviscerated body mass and digestive gland mass relative to mantle length, but the rate of increase for total reproductive organ weight relative to mantle length in females was three times that of males. For females, condition of somatic tissues deteriorated until the mature stage, but somatic condition improved after the onset of maturity. In males, there was no correlation between somatic condition and phases of reproductive maturity. Reproductive investment decreased as sexual maturation progressed for both females and males, with the lowest investment occurring at the functionally mature stage. Residual analysis indicated that female reproductive development was at the expense of body muscle growth during the immature and maturing stages, but energy invested in reproduction after onset of maturity was probably met by food intake. However, in males both reproductive maturation and somatic growth proceeded concurrently so that energy allocated to reproduction was related to food intake throughout the process of maturation. For both males and females, there was little evidence of trade-offs between the digestive gland and reproductive growth, as no significant correlation was found between dorsal mantle length-digestive gland weight residuals. The role of the digestive gland as an energy reserve for gonadal growth should be reconsidered. Additionally, feeding intensity by both males and females decreased after the onset of sexual maturity, but feeding never stopped completely, even during spawning. © 2015 The American Microscopical Society.

Wang J.,Shanghai Ocean University | Wang J.,Collaborative Innovation Center for National Distant water Fisheries | Yu W.,Shanghai Ocean University | Yu W.,Collaborative Innovation Center for National Distant water Fisheries | And 4 more authors.
Scientia Marina | Year: 2016

The western winter-spring cohort of neon flying squid, Ommastrephes bartramii, is targeted by Chinese squid-jigging fisheries in the northwest Pacific from August to November. Because this squid has a short lifespan and is an ecological opportunist, the dynamics of its stock is greatly influenced by the environmental conditions, which need to be considered in its assessment and management. In this study, an environmentally dependent surplus production (EDSP) model was developed to evaluate the stock dynamics of O. bartramii. Temporal variability of favourable spawning habitat with sea surface temperature (SST) of 21-25°C (Ps) was assumed to influence carrying capacity (K), while temporal variability in favourable feeding habitat areas with different SST ranges in different months (Pf) was assumed to influence intrinsic growth rate (r). The parameters K and r in the EDSP model were thus assumed to be linked to temporal variability in the proportion of Ps and Pf, respectively. According to Deviance Information Criterion values, the estimated EDSP model with Ps was considered to be better than the conventional surplus production model or other EDSP models. For this model, the maximum sustainable yield (MSY) varied from 210000 to 262500 t and biomass at MSY level varied from 360000 to 450000 t. The fishing mortality rates of O. bartramii from 2003 to 2013 were much lower than the fishing mortality at target level and MSY level (Ftar and FMSY) and stock biomass was higher than BMSY, suggesting that this squid was not in the status of overfishing and stock was not overfished. The management reference points in the EDSP model for O. bartramii were more conservative than those in the conventional model. This study suggests that the environmental conditions on the spawning grounds should be considered in squid stock assessment and management in the northwest Pacific Ocean. © 2016 CSIC.

Hu G.,Shanghai Ocean University | Fang Z.,Shanghai Ocean University | Fang Z.,Collaborative Innovation Center for National Distant Water Fisheries | Liu B.,Shanghai Ocean University | And 6 more authors.
Fisheries Science | Year: 2016

The beak is a hard structure of cephalopods with relatively constant shape, which records a lot of biological and ecological information. Based on samples collected by Chinese squid jigging vessels off the Peruvian Exclusive Economic Zone from July to October 2013, we explored the feasibility of age estimation and growth pattern with the upper beak of Dosidicus gigas. The internal rostral axis and longitudinal increments could be clearly identified on the upper beak rostrum sagittal sections of this species. Checks and abnormal structure were observed in some beaks. Ages estimated were from 123 to 298 days for females and from 106 to 274 days for males. Back-calculated hatching dates were from December 2012 to May 2013. All of the samples were from the austral summer/autumn spawning cohort. Hatching peak occurred between January and March. Growth in mantle length (ML) and body weight were best described by exponential functions and there were no significant differences between females and males. The maximum absolute daily growth rate and instantaneous growth rate of ML were 2.12 mm/day and 0.59/day, respectively. This study suggests that the upper beak could be used for estimating age, growth and population structure of D. gigas. © 2016 Japanese Society of Fisheries Science

Wang X.-F.,Shanghai Ocean University | Wang X.-F.,National Engineering Research Center for Oceanic Fisheries | Wang X.-F.,Key Laboratory of Sustainable Exploitation Oceanic Fisheries Resources | Wang X.-F.,Collaborative Innovation Center for National Distant Water Fisheries | And 10 more authors.
Chinese Journal of Applied Ecology | Year: 2014

Many pelagic species tend to aggregate under drifting floating objects. This has led to the development of drifting fish aggregation devices (FADs) to attract the tropical tunas for the tuna purse seine fishery. However, FADs can also attract other non-targeting small pelagic species such as rainbow runner Elagatis bipinnulata, although it is still unclear why those species can be attracted and aggregated under an FAD. Using the fishery biological data collected in the Western and Central Pacific Ocean by the scientific observers on board Chinese tuna purse seine fishing vessels, we evaluated the potential motivations for rainbow runner to aggregate under drifting objects. This study indicated 1) Fork length of rainbow runner ranged from 30.0 to 90.6 cm, with the dominant fork lengths of 60.0 to 80.0 cm, accounting for 76.3% of the total sampled fish, suggesting large rainbow runner dominating around the drifting objects; 2) Size (fork length) of E. bipinnulata at 50% maturity was 65.7 cm, and mature individuals were dominant under the FADs; and 3) Some commonly observed small fish species, such as Decapterus macarellus, Kyphosus cinerascens, Caranx sexfasciatus, Katsuwonus pelamis and the juveniles of Thunnus obesus and Thunnus albacares, were found in the stomach of rainbow runner, which suggested that rainbow runner under FAD preyed on other associated small pelagic species. As an oceanic predator associated with drifting objects, feeding is perhaps one of the most possible motivations for adult E. bipinnulata to aggregate under the FAD. Both the "concentration of food supply" hypothesis and the "comfortability stipulation" hypothesis can be used to explain why E. bipinnulata aggregate under drifting floating objects.

Liu Z.-J.,Shanghai Ocean University | Zhu G.-P.,Shanghai Ocean University | Zhu G.-P.,National Engineering Research Center for Oceanic Fisheries | Zhu G.-P.,Collaborative Innovation Center for National Distant water Fisheries
Chinese Journal of Ecology | Year: 2015

Antarctic icefish plays a significant role in the matter cycle and energy flow for Antarctic ecosystem. As a “white blood” fish, its scientific significance and commercial value has been concerned worldwide, but there exist many uncertainties in studies on age and growth of Antarctic icefish. Therefore, the present paper reviewed the research progress of age and growth of Antarctic icefish over the past 50 years, and summarized its classification and general geographical distribution in the Antarctic waters. Based on summarizing the basic methods on age and growth of Antarctic icefish, including length frequency analysis and analysis on calcified structures, this paper put the emphases on processing and estimating the otolith of Antarctic icefish species, and summarized age estimation, morphological feature and microstructure of otolith though pre-processing (direct observation, burning, and sectioning and polishing) of otolith and ring identification on sectioned otolith. Through summarizing the problems and deficiencies, such as the processing of juveniles ' otolith and forming time of first ring, on age and growth estimation of Antarctic icefish species, future research directions were prospected. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved.

Qi D.,Shanghai Ocean University | Qi D.,Collaborative Innovation Center for National Distant water Fisheries | Chen X.J.,Shanghai Ocean University | Chen X.J.,Collaborative Innovation Center for National Distant water Fisheries | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Evaluation the exploitation state of fishery resources can provide a basis for rational utilization of resources. As an ecosystem approach to fisheries management, trophic indicators have been widely adopted to measure the impact of fishing on an exploited ecosystem. Based on the catch data provided by Food and Agriculture Organization of the United Nations, integrating with trophic level of related fish species collected from Fishbase and trophic level of invertebrate provided by Sea Around Us Project database, in order to estimate the state of fishery resources of Pacific Islands, this paper analyzed the fluctuation on mean trophic level (MTL) of Australia, New Zealand, Kiribati and Fiji from 1950 to 2010. Results showed that although a marked decreasing trend in MTL of Australia at a rate of approximately 0.09 trophic levels per decade during 1950-1984, marine fishery resources in Australia were in relatively good condition. When we compute MTL based on time-series of data that exclude trophic levels lower than 3.25 (3.25MTL) so that to eliminate herbivores, detrivores and planktivores whose biomass tends to vary widely in response to environmental factors. 3.25MTL of Australia showed rising trend from 1950 to 2010, suggesting that the decline of MTL was in fact due to the sequential addition of newly exploited species of low trophic level to the multi-species. Fishery resources in New Zealand suffered from a certain degree of overfishing. Although MTL of New Zealand increased substantially since the middle 1970s and fluctuated at high levels during the period 1990-2010, showing no clear decreasing trend. When species whose trophic level is lower than 3.25 were excluded, 3.25MTL of New Zealand first went through a rapid increasing process during the period 1977-1980 and a relatively slow rising process during the period 1981-1998, then 3.25MTL of New Zealand had fallen steadily during the period 1999-2005, and tending towards stability from 2006 to 2010. According to the trophic indicators of Kiribati and Fiji, marine fishery resources in Kiribati and Fiji had not been overfished. But when broadly split this two region's fishery resources into two main categories: offshore and coastal. With the continued rise of catch, MTL of offshore fisheries in Kiribati and Fiji did not show a significant decreasing trend, indicating that offshore resources in Kiribati and Fiji were in a state of accelerated development. However, MTL of coastal fisheries in both countries showed a decreasing trend in recent years, coastal resources in Kiribati and Fiji were in a state of overfishing. In order to promote sustainable development of fishery resources, each country should strengthen resource monitoring and stock assessment so that to better assess the dynamic change of resources under fishing activities. © 2016, Ecological Society of China. All rights reserved.

Cao D.,Shanghai Ocean University | Cao D.,National Engineering Research Center for Oceanic Fisheries | Cao D.,Collaborative Innovation Center for National Distant water Fisheries | Song L.,Shanghai Ocean University | And 7 more authors.
Ocean Engineering | Year: 2014

This study aimed to improve the estimation of the cylinder drag coefficient, and its accuracy for fishing gears. Five surveys on tuna longline fishing grounds were conducted between 2005 and 2010. Collected data include three dimensional current velocities in different water layers and hook depth. Hook depths were calculated by drag coefficients of the cylinder with a perpendicular flow (CN90) of 1.04 to 1.40 (interval of 0.02), and compared with measured depths. The coefficient of variation (CV) was calculated for 70% of the hooks at their measured depths. Additionally, a t-test was conducted comparing depths predicted by the model against measured depths of the remaining sites, totaling 30%. The results showed that the hydrodynamic forces on longline gear have a CN90 between 1.08 and 1.16, and the drag coefficient decreased with increasing Reynolds number (Re, Re<10 3). These results suggest that numerical modeling and at-sea measurement can be used to determine the drag coefficient (CN90) of cylinders such as ropes and lines, and that a drag coefficient of 1.08 to 1.16 are reasonable values for cylinder components of longlines. © 2014 Elsevier Ltd.

Zhu G.-P.,Shanghai Ocean University | Zhu G.-P.,National Engineering Research Center for Oceanic Fisheries | Zhu G.-P.,Collaborative Innovation Center for National Distant water Fisheries
Chinese Journal of Ecology | Year: 2014

Based on the data provided by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the relevant information on the trophic level of selected fish species from Fishbase (www. fishbase. org), this paper analyzed the temporal fluctuation on the mean trophic level (TLi) of the finfish fishery in the Southern Ocean from 1970 to 2009. The results indicated that two stages were observed in the TLi of the finfish fishery in the Southern Ocean, i. e., the TLi had a decreasing trend with a lower level (3. 23-3. 60) from 1970 to 1991; however, the TLi (3. 82-4. 02) were at a higher level from 1992 to 2009. The mean asymptotic length of catch had a similar trend to the mean trophic level. The fishing-in-balance (FiB) index was the highest in 1970 and maintained at a stable level after 1997. © 2014, Editorial Board of Chinese Journal of Ecology. All rights reserved.

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