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1.
深圳海域造礁石珊瑚分布特点与多样性   总被引：1，自引：0，他引：1  
2015年7月,采用国际通用的截线样带法对大亚湾海域的造礁石珊瑚进行普查,并采用ShannonWeaver多样性指数(H')和均匀度指数(J)分析大亚湾海域造礁石珊瑚多样性情况,通过统计造礁石珊瑚覆盖率、死亡率、白化率和基底岩石、碎石、沙子覆盖率来分析大亚湾海域石珊瑚分布特点。结果表明:调查海域共记录54种珊瑚,调查海域主要优势种珊瑚以块状居多,主要为厚板页表孔珊瑚(Montipora incrassata)、团状滨珊瑚(Porites lobata)、隐形角菊珊瑚(Favites abdita)。统计分析数据表明:西涌海域所获珊瑚覆盖率(55%±3%)、多样性(3.039)都较高,但近期珊瑚白化率也较高(6%±2%);东山海域珊瑚覆盖率(13%±2%)、多样性(0.618)均最低。调查海域整体珊瑚覆盖度较高达到41.15%,最高覆盖率为55%,最低覆盖率仅为13%,覆盖度差异较大,近3年内珊瑚死亡率较高,建议加强大亚湾海域珊瑚生态系统的保护。  相似文献   

2.
The silver catfish Rhamdia quelen is a teleost species from South America that can resist cold winters and grow quickly in the summer, representing an important species for aquaculture in both temperate and subtropical climates. NTPDase and 5′-nucleotidase are enzymes responsible for the sequence of ATP dephosphorylation to adenosine in a variety of organs. This enzymatic cascade permits the resultant adenosine to be taken up by the cells. In the present study, membrane fractions of brain, liver and kidney from fish Rhamdia quelen exposed to 15, 23 and 31 °C for 21 days (chronic) or 12 h (acute) were incubated with ATP, ADP and AMP as substrates. In the 21 day experiment the results showed that ATP hydrolysis was enhanced by the increase in temperature in all tissues, except for 31 °C in the brain. NTPDase hydrolysis using ADP as substrate showed a behavior similar to that observed for ATP hydrolysis, except for 31 °C, when the behavior was similar to that observed at 15 °C in the brain. 5′-Nucleotidase activity using AMP as substrate raised with increasing temperature in the three tissues studied. In the 12 h experiment the results obtained for the three temperatures did not differ significantly from each other for any of the tissues. We conclude that after a period of 21 days temperature may affect the activity of NTPDase and 5′-nucleotidase, important enzymes implicated in nucleotide degradation.  相似文献   

3.
Photosynthetic activities of seedlings of Zostera marina were successively measured using a gas volumeter for 6 days at seven light (0–400 μmol photons/m2 per s) and 11 water temperature conditions (5–35°C). The seedlings were collected from mature plants (Ise Bay, central Japan), and stored and cultured in incubators accurately controlled at each test temperature. The maximum gross photosynthesis (P maxg) was recorded at an optimal water temperature of 29°C after 0 days. After 6 days, P maxg appeared at 25°C and most plants cultured at 29–30°C bleached and withered after the drastic increase of light compensation point (I c). On the contrary, at 5–28°C, the photosynthetic activities either changed little (5–25°C) or recovered after a temporal reduction (26–28°C); seedlings survived and looked healthy after being cultured for 6 days. The recovery was thought to be an acclimation to tolerate higher water temperature. As a result, the critical upper water temperature for Z. marina seedlings was proposed as 28°C. The temperature was consistent with the previously reported maximum water temperature in habitats around the southern boundary of Z. marina in the northern hemisphere.  相似文献   

4.
ABSTRACT

Two hundred and thirty-nine albacore tuna (Thunnus alalunga) were troll-caught in the mid-Pacific Ocean and off the US Pacific Coast from June to November 2003. Catch location, harvest date, and sea surface temperature were recorded for individual fish, and lipid and moisture content in the white muscle were determined. The average weight of the alba-core was 6.07 kg and lipid content was highly variable (0.67–18.74%). There was an inverse correlation between the lipid and moisture content of albacore (R2 = 0.93), and percent lipid increased slightly in fish caught later on in the season (R2 = 0.24). Geographical Information Systems (GIS) software was used to determine correlations between lipid content and geographic location. Lipid content varied considerably among tuna caught at similar latitudes; however, most fish caught below 40°N had a lipid content of less than 10%, while the fish with the highest lipid content (13–19% lipid) were all harvested above 40°N.  相似文献   

5.
The main aim of the present work was to evaluate the effect of dietary butylated-hydroxytoulene (BHT as an antioxidant) and dietary lipid level on flesh lipid quality of Beluga sturgeon during frozen storage. An initial 135-day feeding trial evaluated practical-type diets containing 0 or 250 mg BHT kg?1 with two lipid levels (12 and 24% diet on dry matter basis) in a factorial arrangement. Fillet samples were analyzed fresh or after storage at ?18 ± 1°C for 12 months. Dietary antioxidant supplementation had no significant effect on fat content and fatty acid composition in the studied fish muscle, but increasing the lipid concentration in the feed increased muscle lipid concentration. Lipid oxidation in fish muscle is related to increasing lipid concentration in the feed. In addition, oxidation was reduced for fish fed BHT. Results showed that dietary BHT supplementation can slow down the level of lipid oxidation in Beluga sturgeon muscles during frozen storage, but it had a direct relationship with dietary lipid level.  相似文献   

6.
The growth and reproductive cycle of cultured black-lipped pearl oysters, Pinctada margaritifera (L.), were studied in the Gambier Islands (134°52′ W, 23°07′ S) from September 2002 to August 2003. Temperatures were recorded throughout the year, revealing seasonal temperature variations between 22.3 and 27.8°C. The mean annual chlorophyll a value, as computed from satellite data, was 0.188 ± 0.075 μg L−1. To study growth and reproduction, 720 two-year-old individuals were ear hung on long-lines suspended at a depth of 7 m. Samples were taken twice a month to obtain the following measurements: shell height; wet weight of flesh and total oyster; dry weight of adductor muscle, mantle and visceral mass; and glycogen content. Gonad development was also studied by histology on parallel samples. Growth was relatively fast during the first 6 months of the study: average shell height increased from 89.1 ± 9.1 to 119.7 ± 10.8 mm and total weight from 93.4 ± 24.5 to 155.1 ± 33.6 g, between September and the end of March. Subsequently, from April to August, no significant growth was observed for shell and flesh, while the muscle weight decreased significantly. Condition index (CI), defined as the ratio of wet weight of the visceral mass to shell weight, and histological changes in the gonad revealed 3 significant reproductive events of different intensities. The analysis of correlations revealed a specific effect of the chlorophyll a concentration on the growth of shell and soma, and one of the temperature on tissue glycogen content. This study also showed also that CI could be an efficient indicator of reproductive events in pearl oyster. It thus appears that the development of gonads goes on throughout the year in the Gambier Islands, without any detectable phase of sexual rest.  相似文献   

7.
Antioxidative activities of porphyra-334, a mycosporine-like amino acid extracted from laver were evaluated. Oxidation of linoleic acid induced by an alkyl-radical 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH) was successfully suppressed by porphyra-334 (0–200 μM). The simultaneous application of 0.02 μM α-tocopherol and 50 μM porphyra-334 effectively suppressed the AAPH induced oxidation level to approximately 40% of a single application of porphyra-334 after 10 min reaction. Porphyra-334 (0–200 μM) efficiently suppressed the lipid peroxidation induced by singlet oxygen although the antioxidative effect observed was relatively moderate at the initial stage of oxidation. These results suggested that porphyra-334 may function as an antioxidant which influences the storage stability of laver.  相似文献   

8.
To elucidate the effects of seasonal temperature acclimatization on thermal gelation of grass carp myosin, myosins from fish in different seasons were prepared and investigated for the changes in dynamic viscoelastic parameters including storage modulus (G′), loss modulus (G″) and damping factor (tan δ) upon heating. Myosins from fish in spring and summer had a temperature region of 38–44°C for the first marked increase of G′ higher than that of myosins from fish in autumn and winter (28–33°C). The measurement temperature-dependent changes in dynamic viscoelastic parameters such as G″ and tan δ were also different among the four myosins. While gel formation was observed with the spring and summer myosins, apparently in two steps, three steps were found in the autumn myosin. Furthermore, the winter myosin exhibited more than three steps for gel formation. These differences in rheological properties among the four myosins were considered to be attributed to the differences in thermodynamic and structural properties of these myosins previously reported.  相似文献   

9.
Coral larvae, produced from a mass spawning event, were successfully settled on special stone settlement sticks and raised in situ for eventual transport to other reefs. The test area, Sekisei lagoon, Okinawa Prefecture, Japan, is located close to the warm Kuroshio current and is surmised to be the source from which major Japanese corals are derived. A total of 131 settlement sticks, with small holes in their sides to increase protection from grazing (4 mm in diameter and approximately 5 mm deep), were deployed in the lagoon the day before the coral’s mass spawning. After 3 months, 61 sticks were recovered containing 71 corals, mostly in the holes. After 1 year, three corals were confirmed to be growing well and extending outside the holes of the three sticks out of 70 sticks left in the water at the lagoon site. They survived two potentially lethal conditions, that is, high water temperatures with associated extensive coral bleaching and continuous grazing pressure from predators. This procedure is applicable for large-scale coral transplantation, not only in Japan but also in other tropical countries.  相似文献   

10.
Photosynthetic activity of Zostera japonica seedlings was measured using a gas volumeter at 0 and 6 days in culture under eight light (0–800 μmol photons/m2/s) and ten water temperature conditions (5–35°C). Seedlings from Ago Bay, Mie Prefecture were cultured in incubators accurately controlled at each test temperature for 1 week. After 1 week, maximum gross photosynthesis (P maxg) appeared at 29°C and most seedlings cultured at 30–35°C bleached and withered. At the same time, the light compensation point (I c) increased only at 30°C during the culture period. As a result, the upper critical water temperature for survival was 29°C in Z. japonica seedlings, which agrees well with that for the southern boundary of Z. japonica around Japanese coast. It is necessary to monitor this species around this boundary as a bio-indicator for seawater warming.  相似文献   

11.
In this study, juvenile beluga (Huso huso) were fed diets containing different carbohydrate to lipid ratios for 5 months. At the end of the culture period, proximate compositions of the fish carcasses (moisture, protein, fat, and ash) were measured. Then, qualitative changes in the fishes were evaluated during 24-days refrigeration (4°C), along with changes in their total volatile bases nitrogen (TVN), thiobarbituric acid (TBA), free fatty acids (FFA), pH, and muscle texture profile analysis. The results of proximate analysis of the carcasses showed that moisture, protein, and ash of the carcasses increased significantly (p < 0.05) with higher carbohydrate to lipid ratio, but fat content of the carcasses decreased significantly (p < 0.05). Further, during refrigeration, TVN, TBA, and FFA increased significantly in all the samples (p < 0.05), but these changes did not follow the same pattern in all the treatments. Tissue hardness decreased during preservation. Although pH changes in the fillets were low, they were significant and without a clear-cut pattern. The results showed that use of different carbohydrate to lipid ratios in diet does not lead to clear-cut changes in qualitative characteristics of beluga fillets during refrigeration.  相似文献   

12.
《水生生物资源》2002,15(2):107-117
The impetus for this study was the mass bleaching event of giant clams in 1997–1998 at several reefs in the Great Barrier Reef (GBR, Australia). From September until December 1999, the study investigated the effects of high light intensities and increased temperature accompanied by a nutrient limitation on the metabolism of Tridacna gigas, to test, if these environmental changes can induce bleaching. In a 50-day trial similar conditions of the mass bleaching event were imitated stressing clams, collected from Orpheus Island and Nelly Bay, by a two- to threefold light intensity and an increased temperature of 4–6 °C. The objectives of the experiments were to determine whether high light intensities can induce changes in chlorophyll content or alter zooxanthella cell sizes and populations in the tissue. After 50 days of exposure to high light intensity the mantle tissue of stressed clams exhibited a decreased number of zooxanthellae per unit area from 19.8 ± 0.8 (× 107·cm–2) to 0.2 ± 0.2 (× 107·cm–2) (mean ± CL). Additionally, the average cell size of zooxanthellae were downsized from 7.4 ± 0.1 μm to 5.3 ± 0.1 μm (mean ± CL). Subsequently, the chlorophyll content of both, chl a and chl c1, declined as well, chl a from 192 ± 4 to 0.1 ± 0.1 μg·ml–1 and chl c1 from 145 ± 6 to 0 μg·ml–1 (mean ± CL). This study shows that increased light intensity and temperature are the main causes for bleaching in giant clams. Thus, the study confirmed the four major aspects involved in bleaching: (1) loss of symbiotic algae, (2) decrease of chl a/c1 in the remaining symbiotic algae, (3) retention of small zooxanthellae in the tissue and (4) release of ammonium (NH4+) into the water column while nutrient uptake of ammonium was largely blocked.  相似文献   

13.
Three isonitrogenous (320 g kg?1 crude protein, casein and gelatine) semi‐purified diets with 80 (L8), 130 (L13) and 180 (L18) g kg?1 lipid (sunflower oil at increasing levels and cod liver oil fixed at 50 g kg?1) at three digestible energy levels (12 096, 13 986 and 15 876 kJ kg?1 dry weight) and were tested, in triplicate, on rohu fingerlings (3.2 ± 0.08 g) at two different temperatures (21 and 32 °C). Fish were fed to apparent satiation, twice daily, at 09.00 and 15.00 h, 7 days a week for 56 days. Maximum growth was obtained at a lipid level of 80 g kg?1 (L8) at 21 °C (439.37%) and 130 g kg?1 (L13) at 32 °C (481.8%). In general growth rate was higher at 32 °C than at 21 °C at all lipid levels. Tissue monounsaturated fatty acid (MUFA) contents decreased with increasing lipid level at 32 °C, but the reverse occurred at 21 °C. At 21 °C, Polyunsaturated fatty acid (PUFA) level increased significantly (P > 0.05) over initial values, but was affected insignificantly by dietary lipid level. At 32 °C, fish fed diet L13 had more n‐3 fatty acid (FA) in liver and muscle than the other two dietary groups while at 21 °C, both liver and muscle FA profiles exhibited significant change (P > 0.05) in n‐3 and n‐6 FA content which corresponded to variation in percent addition of dietary lipid. However, n‐3/n‐6 ratio was higher for fish fed diet L13 at 32 °C and diet L8 at 21 °C and may be correlated with fish growth.  相似文献   

14.
This study aimed to evaluate the protein-sparing effect of dietary lipid on digestive and metabolic responses of fingerling Megalobrama amblycephala. Fish were fed nine practical diets with three protein levels (270, 310 and 350 g kg−1) and three lipid levels (40, 70 and 100 g kg−1) for 8 weeks. Weight gain was significantly affected only by dietary lipid levels with the highest found in fish fed 70 g kg−1 lipid. Relative feed intake and whole-body protein content showed little difference among all the treatments. Activities of intestine lipase and amylase increased significantly as dietary lipid levels increased, whereas little difference was observed in protease activities. Liver lipid content was significantly affected only by protein levels with the lowest found in fish fed 310 g kg−1 protein. Liver aspartate aminotransferase (GOT) activities increased significantly with decreasing lipid levels, whereas the highest GOT activity was obtained in fish fed 310 g kg−1 protein in terms of dietary protein levels. Activities of liver lipoprotein lipase, total lipase and plasma cholesterol concentration of fish fed 350 g kg−1 protein were significantly lower than that of the other groups, whereas the same was true for plasma 3, 5, 3′-triiodothyronine level of fish fed 270 g kg−1 protein. The results indicated that an increase of dietary lipid content from 40 to 70 g kg−1 can enhance the growth and digestive enzyme activities of this species and reduce the proportion of dietary protein catabolized for energy without inducing hepatic steatosis; meanwhile, decreasing protein level from 350 to 310 g kg−1 leads to the increase of lipase activities both in intestine and liver coupled with the reduced liver lipid content.  相似文献   

15.
Several of the world's major spiny lobster fisheries, including Jasus edwardsii in Australasia, have gone into dramatic decline due to decreasing recruitment of their lecithotrophic postlarvae. There is evidence that the decline is related to poor nutritional condition of the postlarvae, especially lipid that is accumulated in large quantities during the preceding pelagic larval stage. Therefore, characterizing the lipid composition of the likely potential zooplankton prey of the larvae (phyllosomas) of spiny lobsters will provide new insights into their nutritional requirements. The lipid class and fatty acid composition of more than 30 species of likely zooplankton prey of the larvae of the spiny lobster, J. edwardsii, were determined. These results showed that most zooplankton prey had a high proportion of their lipid content as polar lipid (PL) (range of 9.4–94.8%, mean of 76.1 ± 2.6%). Zooplankton prey provide phyllosomas with polyunsaturated fatty acids (PUFA) for growth and development, as well as a range of other important fatty acids that are accumulated as PL and used for fuelling the migration of the subsequent lecithotrophic postlarvae across the continental shelf. Overall, these results indicate that phyllosomas consume prey with wide ranging lipid content, but dominated by PL, and high in docosahexaenoic acid, eicosapentaenoic acid and the key fatty acids used for energy storage.  相似文献   

16.
The aim of the study was to evaluate the effect of short-term starvation on the morphology of the digestive system of juvenile tench Tinca tinca (L.). The morphological changes in digestive structures of juveniles, fed 70 days starter or Chironomidae larvae, were examined after 1, 12, 24 and 48 h of starvation at 28 °C. The morphological changes in the organisation of the digestive structures were as follows: (1) Intestine – proteolysis of the intestinal mucosa, especially of enterocytes in apical part of mucosal folds; (2) Liver – progressive reduction of lipid vacuoles and glycogen granules, and, in effect, volume reduction of hepatocytes cytoplasm; (3) Pancreas – progressive degeneration of exocrine pancreatic cells, parallel with decrease of zymogen activity. The fish fed natural food prior to starvation seem to be more resistant to starvation than those fed starter.  相似文献   

17.
Copepod oil (CO) from the marine zooplankton, Calanus finmarchicus, is a potential alternative to fish oils (FOs) for inclusion in aquafeeds. The oil is composed mainly of wax esters (WE) containing high levels of saturated fatty acids (SFAs) and monounsaturated fatty alcohols that are poorly digested by fish at low temperatures. Consequently, tissue lipid compositions may be adversely affected in salmon‐fed CO at low temperatures. This study examined the lipid and FA compositions of muscle and liver of Atlantic salmon reared at two temperatures (3 and 12 °C) and fed diets containing either FO or CO, supplying 50% of dietary lipid as WE, at two fat levels (～330 g kg?1, high; ～180 g kg?1, low). Fish were acclimatized to rearing temperature for 1 month and then fed one of four diets: high‐fat fish oil (HFFO), high‐fat Calanus oil (HFCO), low‐fat fish oil (LFFO) and low‐fat Calanus oil (LFCO). The fish were grown to produce an approximate doubling of initial weight at harvest (220 days at 3 °C and 67 days at 12 °C), and lipid content, lipid class composition and FA composition of liver and muscle were determined. The differences in tissue lipid composition between dietary groups were relatively small. The majority of FA in triacylglycerols (TAG) in both tissues were monounsaturated, and their levels were generally higher at 3 °C than 12 °C. Polyunsaturated fatty acids (PUFA), particularly (n‐3) PUFA, predominated in the polar lipids, and their level was not significantly affected by temperature. The PUFA content of TAG was highest (～26%) in the muscle of fish fed the HFCO diet at both temperatures. Tissue levels of SFAs were lower in fish‐fed diets containing HFCO than those fed HFFO, LFFO or LFCO, particularly at 3 °C. The results are consistent with Atlantic salmon being able to incorporate both the FA and fatty alcohol components of WE into tissue lipids but, overall, the effects of environmental temperature on tissue lipids were more pronounced in fish fed the CO diets than FO diets.  相似文献   

18.
The aim of this study was to investigate the relationship between lipid oxidation, protein function properties, and freshness changes of blunt-snout bream (Megalobrama amblycephala) fillets treated with 2% and 4% salt during storage at 4°C. Salting with 2% and 4% salt could delay quality deterioration and protein denaturation, thus improving sensory attributes to some extent. But, 4% salt promoted lipid oxidation of blunt-snout bream fillets. There is a significant correlation (p < 0.05) between freshness indexes and lipid oxidation or protein function properties (total SH content, Ca2+-ATPase activity). Salting with 2% salt is an ideal treatment to control the quality of blunt-snout bream fillets stored at 4°C.  相似文献   

19.
ABSTRACT

Lipid and protein oxidation in catfish (Clarias lazera) surimi during processing and storage were assessed. Catfish surimi were washed in deionized water: M0 (no washing step), M1 (one washing step), and M2 (two washing steps). Lipid, protein, water, and iron contents were determined. M0, M1, and M2 were stored for 0, 1, 4, 7, or 10 days at 4 ± 1°C; at each time point, samples were removed for analyses. Lipid oxidation was assessed by measuring malondialdehyde content. Protein oxidation was assessed by measuring protein solubility and protein sulfhydryl and carbonyl group contents. Based on the results, lipid content, L* and a* (color parameters), and fatty acid content in M1 and M2 were significantly reduced. Lipid oxidation development was faster in M1, and the ranking was as follows: M1 > M2 > M0, with M0 being significantly less oxidized than M1. Increasing the number of washes increased protein oxidation, and the ranking was follows: M2 > M1 > M0. Altogether, lipid and protein oxidation and physicochemical changes occurred simultaneously to different degrees in surimi during various processing and storage conditions.  相似文献   

20.
The aim of the present study was to evaluate the effects of various sous-vide time–temperature regimes and their interactions on quality parameters of Atlantic mackerel (Scomber scombrus) during chilled storage. The mackerel ?llets were exposed to sous-vide treatment at 60, 75, and 90°C for 10, 15, and 20 min and further stored for 1, 3, and 7 days at 4 ± 1°C before analysis. Changes in pH, water content and cook loss, amount of water- and salt-soluble proteins, texture, and color parameters, as well as accumulation of lipid oxidation products in sous-vide-cooked mackerel were assessed. Sous-vide cooking time and temperature had the lowest contribution to the formation of primary and secondary products of lipid oxidation, as well as increase in yellowness of the fish flesh due to their accumulation; whereas duration of chilled storage led to a significant increase in oxidation and yellowness (p < 0.05). Duration of chilled storage also affected structural and textural properties of the fish muscle, leading to a decreased cook loss. At the same time, sous-vide cooking decreased the firmness of the fish muscle. Duration of chilled storage was found to have the highest significant effect (p < 0.001) on all physicochemical characteristics of sous-vide-cooked mackerel.  相似文献   

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