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The mechanical reliability of calcium phosphate cements has restricted their clinical application in load-bearing locations. Although their mechanical strength can be improved using a variety of strategies, their fatigue properties are still unclear, especially after degradation. The evolutions of uniaxial compressive properties and the fatigue behavior of calcium phosphate cements incorporating poly (γ-glutamic acid) and its strontium salt after different in vitro degradation times were investigated in the present study. Compressive strength decreased from the 61.2±5.4 MPa of the original specimen, to 51.1±4.4, 42.2±3.8, 36.8±2.4 and 28.9±3.2 MPa following degradation for one, two, three and four weeks, respectively. Fatigue life under same loading condition also decreased with increasing degradation time. The original specimens remained intact for one million cycles (run-out) under a maximum stress of 30 MPa. After degradation for one to four weeks, the specimens were able to withstand maximum stress of 20, 15, 10 and 10 MPa, respectively until run-out. Defect volume fraction within the specimens increased from 0.19±0.021% of the original specimen to 0.60±0.19%, 1.09±0.04%, 2.68±0.64% and 7.18±0.34% at degradation time of one, two, three and four weeks, respectively. Therefore, we can infer that the primary cause of the deterioration of the mechanical properties was an increasing in micro defects induced by degradation, which promoted crack initiation and propagation, accelerating the final mechanical failure of the bone cement. This study provided the data required for enhancing the mechanical reliability of the calcium phosphate cements after different degradation times, which will be significant for the modification of load-bearing biodegradable bone cements to match clinical application. [ABSTRACT FROM AUTHOR]

Information of vertical distribution of longline-hook species is important for the development of effective measures to mitigate bycatch, and very helpful for better understanding of the oceanic ecosystem structure and implementation of ecosystem-based fisheries management. Based on depth data of longline hook and capture hook position of pelagic species, collected by on board scientific observer in the southeast Pacific Ocean from September 2013 to January 2014, shoaling rate of longline hook and vertical distribution of 14 pelagic species were analyzed. The results showed that the relative shoaling rate range of longline hook was 8.9%-17.1%, and the average relative shoaling rate was 13.5%. The depth ranges of 14 capture species were different. The species with the deepest depth was Opah (Lampris guttatus) , and the species with the shallowest depth was skipjack (Katsuwonus pelamis). Except for yellowfin tuna (Thunnus albacares) and striped marlin (Tetrapturus audax) , the mean depth and depth distributions of bycatch species were significantly different from that of the targeted albacore tuna (Thunnus alalunga). [ABSTRACT FROM AUTHOR]

Stable isotope analysis (SIA) has become an important tool to investigate diet shift, habitat use and trophic structure of animal population. Muscle is considered to be the most common tissue for SIA, however, lipid content in muscle causes a considerable bias to the interpretation of isotopic ratios of animals. Neon flying squid (Ommastrephes bartramii) is an important economic cephalopod of Chinese distant water fishery, and plays a major role in marine ecosystems. In this study, the effects of lipid extraction on stable isotope ratios of the muscles of 53 neon flying squids were investigated and the interference mechanism of lipid in SIA was clarified with the aim of contrasting the suitability of different lipid correction models of stable carbon isotope. Results showed that the stable carbon and nitrogen isotopic values of non-lipid extracted samples significantly increased after lipid extractions by 0. 71‰ and 0. 47‰, respectively, which suggested that lipid extraction in cephalopod isotope study is needed prior to stable carbon isotope analysis but not recommended for stable nitrogen isotope analysis. The results could help remove the effects of lipid contents and standardize SIA muscle samples, thereby getting better understanding of the isotopic change of neon flying squids in the future. [ABSTRACT FROM AUTHOR]

Coilia nasustaihuensis is the most abundant species in Dianshan Lake and plays an important role in the lake ecosystem. From July 2010 to August 2011, a total of 3107 samples of C. nasustaihuensis were collected from Dianshan Lake. Based on length data of these samples, ELEFAN I technique was employed to estimate growth and mortality parameters, and the Beverton-Holt dynamic model was used to evaluate the population dynamics trend for C. nasustaihuensis. Growth of this species was described using a von Bertalanffy model, and the estimated parameters were L∞=35. 70 cm, k =0. 54, and t0 =-0. 48 a. The turning point for body mass growth curve of the stock was situated at t =1. 37 a. Natural mortality coefficient M was then estimated using Pauly's empirical equation and found to be 0. 872. Length-converted catch curves were used to estimate the total mortality coefficient Z, which was found to be 2. 121. Accordingly, the fishing mortality coefficient (F) was equal to 1. 249, and the current exploitation rate was 0. 589, suggesting the stock was over-exploited. According to the Beverton-Holt dynamic model, the minimum capture size for C. nasustaihuensis should be 21. 42 cm (age 1. 22 years). [ABSTRACT FROM AUTHOR]

Decapterus maruadsi is an important economic pelagic fish in the southern coastal area of Zhejiang. According to the bottom trawl surveys conducted in May, August, November 2020 and January 2021, the feeding habits of D. maruadsi in the southern coastal area of Zhejiang were examined by both stable isotope (carbon, δ 13 C, and nitrogen, δ 15 N) and stomach content analyses. Results showed that the δ 13 C value of D. maruadsi ranged from -17.76‰ to -15.25‰, with a mean of (-16.55±0.60)‰, while the δ 15 N value ranged from 9.06‰ and 13.03‰, with a mean of (11.76±0.88)‰. There was a significant negative correlation between the δ 13 C values and fork length, and a positive relationship between the δ 15 N with fork length. Results from stomach content analysis showed that the main prey groups of D. maruadsi were fish, shrimp, crabs, Cephalopod, Polychaete, and small crustaceans. As for the stable isotope analysis, the nutritional contribution rate of shrimp was the highest (40%-84%) among all prey groups, followed by Polychaete, small crustaceans, crabs, Cephalopods and fish. Significant ontogenetic dietary changes were found for D. maruadsi . As the fork length of D. maruadsi increased, it tended to eat prey from higher trophic levels.

The variations of life history traits have been observed for many fish species, which gains much concerns in the study of aquatic biology and ecology. In this study, the biological characteristics were explored for yellow croaker ( Larimichthys polyactis ) in the offshore waters of southern Zhejiang, based on 4920 individuals collected from 13 fishery-independent seasonal surveys from autumn 2015 to autumn 2018. Linear mixed effects models were used to estimate the growth, maturity characteristics, and their heterogeneity. The body length of yellow croaker samples ranged from 13 to 215 mm with the dominant body of 110 to 154 mm. The body weight ranged from 0.5 to 182.2 g, with the dominant body weight from 20 to 55 g. The results showed that the linear mixed effects models with random effects from season, gender, and year performed best for length-weight relationship, with the lowest AIC and RMSE values. The effects of season were much larger than those of genders and years. When the length exceeded 160 mm, the weight gain rate of yellow croaker was faster in spring and summer, lower in autumn and winter, while the male individuals gained more weight than the females with the same body length. Among 4841 individuals of specimens with gonadal data, the individuals at maturity Ⅱ stage occupied 50.4%, and the individuals at maturity stage contributed to 19.6%. The results from the best linear mixed effects model showed that season had the most significant influence on the maturity of yellow croaker. The 50% maturity length ( L 50% ) was much lower in winter (124.6 mm) with no much difference between other seasons, indicating that yellow croaker matures earlier in winter. Our results indicated that linear mixed effect model could reflect the biological heterogeneity of yellow croaker conveniently and that the growth and maturity of yellow croaker had significantly sexual and temporal variations, which should be considered in the stock assessment and fishery management for yellow croaker.

Based on data from November of 2015 (autumn), February (winter), May (spring), and August (summer) of 2016 in the offshore waters of southern Zhejiang Province, the relationships between major shrimps species were examined by niche breadth, niche overlap, variance ratio, chi-square test, association coefficient and species pair co-occurrence percentage. The results showed that temporal niche breadth of Atypopenaeus stenodactylu was the largest, spatial niche breadth of Solenocera crassicornis was the largest, and A. stenodactylu had the largest spatio-temporal niche breadth. The temporal niche overlap between Parapenaeus fissuroides and Parapenaeopsis tenella was the highest. The spatial niche overlap between Solenocera koelbeli and Penaeus chinensis, P. fissuroides and Heterocarpoides laevicarina were the highest. The spatio-temporal niche overlap between S. koelbeli and P. chinensis was the highest. The analysis of variance ratio showed that the main shrimp species were significantly positively correlated. Positive correlation existed in 13 pairs (χ 2 ≥3.841). Results from the association coefficient (AC) and co-occurrence percentage (PC) indicated that the interspecific association tended to be positive. Our results provide supports for exploring niche breadth and niche overlap of major shrimp species and improving niche differentiation.

Based on data collected from four trips of trawl surveys in offshore water of southern Zhejiang in 2015-2016, a generalized additive model was used to analyze the distribution of small yellow croaker (Larimichthys polyactis) and its relationship with environmental factors. The results showed that the highest resource abundance occurred in the summer trip, primarily in Yushan fishing ground with an average density of 500.74 kg·h -1 ·km -2 . Environmental factors influencing the density and distribution of small yellow croaker changed with season. The effect of environmental factors on the resource density of small yellow croaker was not significant in autumn. In spring, the small yellow croaker mainly distributed in waters with high salinity, while both sea bottom temperature and salinity had negative correlation with resource density of small yellow croaker in summer, and the fish habited in Yushan waters with middle temperature and high salinity. In winter, water temperature had a positive relationship with resource density of small yellow croaker which primarily distributed in waters of outside stations with suitable temperature. Generally, the distribution characteristic of small yellow croaker accorded to its migration habit. It was hard to explain the relations between environmental factors and resource density of small yellow croaker, which needed to further study. The results are helpful for understanding the living behavior and the conservation and management of the small yellow croaker stock in offshore water of southern Zhejiang.

The blue shark, Prionace glauca, is the main by-catch species in tuna longline fishery. As one of top species in the oceanic food webs, the blue shark plays an important role in the marine ecosystem. Traditional stock assessment methods are difficult to accurately evaluate the population dynamic for this shark because of limited data. Based on life-history parameters of the blue shark in the North Atlantic, demographic analysis was employed to estimate the demographic parameters and evaluate the potential exploitation for the blue shark. Moreover, we discussed the relationship between age at first capture and critical value of fishing mortality corresponding to the value of intrinsic rate of natural increase 0. The results showed that the survival rate (S) of blue shark from 0.719 to 0.820, intrinsic rate of natural increase (r0) from 0.250 to 0.381, time of population doubling (tx2) from 1.819 to 2.773 years, reproduction rate per generation (R0) from 6.600 to 22.255, and generation time (G) from 8.498 to 10.162 years. The sensitivity analysis for the life history parameters revealed that the uncertainties of natural mortality existed in the first age class, age at maturity and maximum age had slight influence on the demographic parameters. Fishing mortality (Fc) increased with the age at first capture. When the age at first capture (tc) was more than five, there was no obvious relationship between Fc and tc.

Information of vertical distribution of longline-hook species is important for the development of effective measures to mitigate bycatch, and very helpful for better understanding of the oceanic ecosystem structure and implementation of ecosystem-based fisheries management. Based on depth data of longline hook and capture hook position of pelagic species, collected by on board scientific observer in the southeast Pacific Ocean from September 2013 to January 2014, shoaling rate of longline hook and vertical distribution of 14 pelagic species were analyzed. The results showed that the relative shoaling rate range of longline hook was 8.9% - 17.1%, and the average relative shoaling rate was 13.5%. The depth ranges of 14 capture species were different. The species with the deepest depth was Opah (Lampris guttatus), and the species with the shallowest depth was skipjack (Katsuwonus pelamis). Except for yellowfin tuna (Thunnus albacares) and striped marlin (Tetrapturus audax), the mean depth and depth distributions of bycatch species were significantly different from that of the targeted albacore tuna (Thunnus alalunga).

Stable isotope analysis (SIA) has become an important tool to investigate diet shift, habitat use and trophic structure of animal population. Muscle is considered to be the most common tissue for SIA, however, lipid content in muscle causes a considerable bias to the interpretation of isotopic ratios of animals. Neon flying squid (Ommastrephes bartramii) is an important economic cephalopod of Chinese distant water fishery, and plays a major role in marine ecosystems. In this study, the effects of lipid extraction on stable isotope ratios of the muscles of 53 neon flying squids were investigated and the interference mechanism of lipid in SIA was clarified with the aim of contrasting the suitability of different lipid correction models of stable carbon isotope. Results showed that the stable carbon and nitrogen isotopic values of non-lipid extracted samples significantly increased after lipid extractions by 0.71 per thousand and 0.47 per thousand, respectively, which suggested that lipid extraction in cephalopod isotope study is needed prior to stable carbon isotope analysis but not recommended for stable nitrogen isotope analysis. The results could help remove the effects of lipid contents and standardize SIA muscle samples, thereby getting better understanding of the isotopic change of neon flying squids in the future.

Coilia nasustaihuensis is the most abundant species in Dianshan Lake and plays an important role in the lake ecosystem. From July 2010 to August 2011, a total of 3107 samples of C. nasustaihuensis were collected from Dianshan Lake. Based on length data of these samples, ELEFAN I technique was employed to estimate growth and mortality parameters, and the Beverton-Holt dynamic model was used to evaluate the population dynamics trend for C. nasustaihuensis. Growth of this species was described using avon Bertalanffy model, and the estimated parameters were Linfinity = 35.70 cm, k = 0.54, and t0 = -0.48 a. The turning point for body mass growth curve of the stock was situated at t = 1.37 a. Natural mortality coefficient M was then estimated using Pauly's empirical equation and found to be 0. 872. Length-converted catch curves were used to estimate the total mortality coefficient Z, which was found to be 2.121. Accordingly, the fishing mortality coefficient (F) was equal to 1.249, and the current exploitation rate was 0. 589, suggesting the stock was over-exploited. According to the Beverton-Holt dynamic model, the minimum capture size for C. nasustaihuensis should be 21.42 cm (age 1.22 years).