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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. Source


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. Source


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. Source


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. Source


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. Source

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