首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 62 毫秒
1.
Some hydrological features of Hawke Bay and nearby shelf waters   总被引：3，自引：3，他引：0  
Temperature and salinity observations were made in Hawke Bay (east coast, North Island) and in the near shore coastal shelf water immediately to’ the south. Water in the bay was cooler and less saline than the shelf water on the open coast to the south. Hydrological analysis confirms that the main inflow is westward along the approximate centre line of the bay.  相似文献   

2.
Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.  相似文献   

3.
Drift cards were released in batches of 50 every 2 d at drilling sites off the north and south Taranaki coast (May‐October 1975), Banks Peninsula (July‐August 1975), and in Tasman (January‐March 1976) and Hawke Bays (November 1975‐January 1976). The shortest distance “despatch to recovery” trajectories indicate that only in the South Taranaki Bight are the trajectories predominantly unidirectional, the surface drift being southwards on the west coast of the North Island south of Cape Egmont. The trajectories of cards despatched in both Tasman and Hawke Bays highlight the variable nature of the surface drift in these bays.  相似文献   

4.
The wave climate at the Maui site off the west coast of the North Island and off the east coast of Great Barrier Island to the east of the North Island are examined. This is done by means of average wave spectra derived from a 2‐year database, acquired from Waverider buoy measurements made over 1980 and 1981. The average spectra provide information about the individual sea states which characterise the wave climate, and show that on average the sea state on the east coast is less energetic than it is on the west coast. Further, it is seen that this difference results largely from a dominant and persistent long‐period south‐westerly swell of 12.4 s period which is present at the Maui location but absent from the Great Barrier Island seas.  相似文献   

5.
Two species of spiny lobsters (marine crayfish) inhabit New Zealand waters: Jasus edwardsii (Hutton, 1875), and J verreauxi (H. Milne Edwards, 1851). J edwardsii, the more common species, is present along most rocky coastlines in New Zealand, but is more abundant in the south‐west of the South Island and at the Chatham Islands. The species apparently reaches its northern limit of distribution at the Three Kings Islands (34°S) and its southern limit at the Auckland Islands (51°S).

J. verreauxi, the less common species, is almost solely restricted in New Zealand waters to the north‐east coast of the North Island. It is uncommon in the west and the south of the North Island, and is rare in the South Island. J. verreauxi apparently reaches its northern limit of distribution at the Kermadec Islands (31°S), and its southern limit near Bluff (47°S) in the South Island.  相似文献   

6.
采用聚丙稀酰胺凝胶电泳技术对福建平潭岛、浙江象山港、江苏海州湾和辽宁辽东湾4个海区菲律宾蛤仔(Ruditapes philippinarum)野生群体的生化遗传特征进行了分析.结果表明,菲律宾蛤仔4个群体的多态位点比例为62.5%～75.0%,平均杂合度观测值在0.274 3～0.338 7之间,与平均杂合度期望值相近;平均有效等位基因数在1.489 1～1.632 5之间,遗传变异水平较高;杂合子缺失不显著.比较群体间的遗传分化指数和群体每代迁移数发现,平潭岛、象山港和海州湾3个群体间的遗传分化不显著,而辽东湾群体与3个群体间出现遗传差异.聚类分析同样表明,平潭岛群体首先与象山港群体聚类,再与海州湾群体相聚,最后与辽东湾群体相汇.讨论了杂合子缺失不显著原因和群体间遗传分化机制.  相似文献   

7.
Circulation in Tasman Bay   总被引：4，自引：4，他引：0  
Direct current measurements at four locations in Tasman Bay and numerical model results are used to analyse the mean flow in Tasman Bay. The mean circulation conforms to that previously found from drift card experiments: a clockwise circulation in Golden Bay, and an anti‐clockwise flow in Tasman Bay, with a return south‐westerly flow on the coast near Nelson. Typical mean speeds are 0.02–0.05 m.s‐1. The circular flow appears asymmetrical in both bays, with a stronger outflow along Farewell Spit in Golden Bay and near D'Urville Island in Tasman Bay.

An analytical tidal solution is used to exhibit the influence of Cook Strait in producing smaller tidal amplitudes in eastern Tasman Bay. Tidal speeds of 0.15–0.30 nus‐1 are typical, with tidal ellipses having degenerated into north‐east, south‐west lines.  相似文献   

8.
A litter of eight near‐term shortfin mako (Isurus oxyrinchus Rafinesque 1810) embryos is described from a 317.5 cm total length (TL) female caught off Hawke Bay, south‐east North Island, New Zealand on 5 February 1999. The embryos (3 males and 5 females) were 67.2–77.0 cm TL. Embryo length, condition, hepato‐somatic indices, and mass of yolk in their stomachs all indicate they were close to birth. This is the first shortfin mako litter reported from New Zealand and is outside the late winter‐early spring parturition period predicted from estimated embryonic and juvenile growth rates. Uterine width data from four mature non‐pregnant females and age‐0+ length‐at‐capture data suggest parturition occurs from September to late February (late winter‐mid summer) but is infrequent after January. We suggest that shortfin makos have an extended parturition period, possibly year‐round, with peak parturition occurring in late winter‐spring.  相似文献   

9.
The numbers of dorsal and anal fin rays were compared in samples of sand flounder Rhombosolea plebeia (Richardson) collected from different localities around the coasts of New Zealand. Fin ray numbers were highest on the west coast of the North Island, particularly in the South Taranaki Bight, and were lowest on the east and south coasts of the South Island. Within the areas studied five regions were recognised within which the mean numbers of fin rays were relatively constant, but between which the mean numbers of fin rays differed considerably. The significance of these differences is discussed.  相似文献   

10.
Abstract

In September 1986, dense concentrations of freshly spawned hoki (Macruronus novaezelandiae) eggs were located in eastern Cook Strait. A follow‐up exploratory trawl survey of Cook Strait and the east coast of the South Island, in August and September 1987, located concentrations of spawning hoki in canyon features in Cook Strait, off the Kaikoura coast, and off Banks Peninsula. The largest concentration, 14 km long, 4 km wide, and up to 150 m thick occurred in Cook Strait Canyon, with catch rates of hoki up to 48 t h?1. Gonad conditions of male and female hoki showed they were actively spawning. Catch rates in Cook Strait Canyon were comparable to the main fishery on the west coast of the South Island but were much lower off Kaikoura and Banks Peninsula. Hoki associated with spawning concentrations were not feeding. Bycatch species were mostly ling (Genypterus blacodes) and spiny dogfish (Squalus acanthias), and both were preying on hoki. Spiny dogfish were also feeding on spawned fish eggs. The possible stock structure of hoki is discussed.  相似文献   

11.
Photo‐identification has been established as a helpful tool in cetacean research. However, no study to date has attempted to apply this method to short‐beaked common dolphins (Delphinus delphis L.). We present here the results of two studies that were conducted concurrently in Mercury Bay and the Hauraki Gulf on the north‐east coast of New Zealand's North Island. Methods for distinguishing between individual dolphins are discussed. Sighting records of recognisable individuals indicate that some common dolphins move between Mercury Bay and the Hauraki Gulf (100 km distance), as well as between Mercury Bay and Whakatane (200 km distance). Common dolphin abundance and site fidelity appeared to be greater in the Hauraki Gulf than in Mercury Bay. A selection of photographs of distinct individuals is presented to allow future studies to compare their sighting records to ours, which may help establish the extent of home ranges, site fidelity, and possibly even longevity for common dolphins.  相似文献   

12.
We describe the development and application of a management procedure (decision rule) that resulted in a voluntary reduction in the commercial catch of spiny rock lobster (Jasus edwardsii) in the lower east coast of North Island of New Zealand. The management procedure was developed from an accepted assessment of the CRA 4 (Wellington‐Hawke's Bay) fishery, which used an integrated length‐based assessment model fitted to commercial fishery catch‐per‐unit‐effort (CPUE) biomass indices, commercial length‐frequency data, and tag‐recapture data. The assessment model had been Bayesian, and used the joint posterior distribution of parameters to predict the effect of 384 alternative harvest control rules on the future size of the CRA 4 stock. The harvest control rules all used CPUE as their input, and generated annual changes in catch, which were then simulated by the population dynamics of the operating model. Uncertainty was added to evaluations through observation error, added to the simulated CPUE observations, and stochastic serial auto‐correlation variation in recruitment. We describe how this management procedure was used to effect a voluntary reduction in catch to address the problem of a rapidly declining population.  相似文献   

13.
The freshwater calanoid copepods Boeckella triarticulata and B. hamata were found in ponds near Napier. These are the first records of B. triarticulata in the North Island, New Zealand and of B. hamata in the east coast, North Island.  相似文献   

14.
Data from 36 whale shark (Rhincodon typus Smith, 1828) sightings off north‐east North Island, New Zealand are summarised. Sightings were concentrated over the outer shelf and shelf break in areas influenced by the East Auckland Current at sea surface temperatures (SST) of 21–24°C. Sightings occurred from late spring to early autumn (November‐April) but were most frequent in midsummer (February) when upwelling along the north‐east shelf is weakest. The data indicate whale sharks occur off north‐east New Zealand most summers, including those when SST is colder than usual. A cluster of sightings and three observations of whale sharks feeding on schools of anchovy (Engraulis australis) near Whale Island, Bay of Plenty, suggest whale sharks may aggregate seasonally in this area. Estimated total lengths (TL) of 26 whale sharks ranged from 3.5 to 15 m, with 73% between 6 and 9 m TL.  相似文献   

15.
The input of river-borne sediments to the New Zealand continental shelf has been calculated for all the major rivers and basins in New Zealand. South Island yields 284 ± 40 × 106 tonnes per year of sediment from a land area of 152 977 km2 and North Island yields 105 ± 9·4 × 106 tonnes per year from a land area of 114 621 km2. Particularly high discharges are noted off the west coast of South Island and east coast of North Island and result in higher offshore sedimentation there. The data are compatible with measured sedimentation rates on the New Zealand continental shelf. The specific sediment yield from South Island is amongst the highest previously recorded.  相似文献   

16.
Hoki (Macruronus novaezelandiae Hector) year class strength (YCS) varies substantially from year to year. We examined associations between YCS and climate variables including the Southern Oscillation Index (SOI), satellite sea surface temperatures (SSTs), synoptic weather patterns, wind speeds, and the depth of the west coast, South Island, New Zealand, mixed layer. We evaluated the predictions of a model developed 2 years ago to predict YCS of the western and eastern New Zealand hoki stocks from similar climate variables. New predictive models were developed using updated data. Strong year classes of the western hoki stock were associated with cooler SSTs, a negative SOI, and westerly or south‐westerly flow along the west coast of the South Island. We accordingly predict a moderately strong 1997 year class and weak 1998 and 1999 year classes for the western stock of hoki. The current model cannot predict eastern stock year class strengths with confidence.  相似文献   

17.
Genetic and morphological variation within the southern African population of Lampanyctodes hectoris was analysed. A total of 15 enzymes, encoding 22 isozyme loci, was examined (n = 327); seven were polymorphic. The percentage of polymorphic loci ranged from 13.6 to 27.3%. The mean heterozygosity was generally low and ranged from 0.003 to 0.005. Genetic divergences between specimens from four areas along the west coast of southern Africa were negligible, genetic distance values (D) ranging from 0 to 0.00011. The results showed the population of L. hectoris to be genetically invariant. Principal Component Analysis was performed separately on ratios of 13 morphometric and 6 meristic variables (n = 446), and there was evidence of extensive overlap between fish from all areas. However, discriminant analysis suggested some morphological variability within this population. Although genetically the population of L. hectoris seems to be homogenous, morphologically it appears to be variable. A combination of these results suggests that there is no clear genetic basis for the slight morphological differentiation within the population.  相似文献   

18.
本研究于2020年7月在大亚湾及大鹏半岛沿岸开展造礁石珊瑚的分布、覆盖率、死亡率、硬珊瑚补充量和物种多样性调查。结果表明：24个站位共发现造礁石珊瑚9科17属44种以及5个未定种,其中裸肋珊瑚科的种类最多,有7属27种,其次为鹿角珊瑚科和滨珊瑚科,均有2属6种;中央列岛沿岸造礁石珊瑚平均覆盖率为12.0%,三门岛沿岸平均覆盖率为12.9%,大鹏半岛沿岸平均覆盖率为5.2%;以坚实滨珊瑚（Porites solida）、翼形蔷薇珊瑚（Montipora peltiformis）、五边角蜂巢珊瑚（Favites pentagona）和多孔同星珊瑚（Plesiastrea versipora）等为优势种;造礁石珊瑚物种多样性较高。与历史数据相比,大亚湾及大鹏半岛沿岸造礁石珊瑚退化严重,活珊瑚覆盖率锐减,优势种由分支状珊瑚逐步转变为皮壳状或亚团块状珊瑚。此外,本研究构建了近岸造礁石珊瑚生态脆弱性评价体系,并对目前大亚湾及大鹏半岛沿岸造礁石珊瑚进行了生态脆弱性评价。结果显示,中央列岛、三门岛和大鹏半岛东侧海域造礁石珊瑚处于低或中脆弱状态;较场尾、杨梅坑、西冲和大鹏半岛西侧海域造礁石珊瑚处于高或很高脆弱状态,在环境压力影响下其受损可能性较高。在海水养殖、渔业捕捞、滨海旅游和船舶航行等日益频繁的人类活动下,大亚湾及大鹏半岛沿岸造礁石珊瑚整体处于中高脆弱状态,建议加强珊瑚礁监测,并采取相应的保护措施。  相似文献   

19.
Genetic variability of the Kunene horse mackerel Trachurus trecae and the Cape horse mackerel Trachurus trachurus capensis was examined using starch gel electrophoresis of enzymatic proteins on individuals collected along the Angolan coast. Six polymorphic enzyme loci were found in both species. The idh-2* locus displayed differences between the two species, and several alleles at different loci exhibited different allele frequencies between the two species, indicating that they are genetically different. Significant differences found in the distribution of allele frequencies between Kunene horse mackerel from the Benguela region of Angola indicated that this species consist of more than one randomly mating population in Angolan waters.  相似文献   

20.
The collector sea urchin Tripneustes gratilla has been identified as a species with potential for aquaculture production in South Africa. The species’ roe is considered a culinary delicacy in Asia and Europe. However, T. gratilla remains genetically uncharacterised in South Africa. Therefore, the purpose of this study was to provide baseline genetic information consisting of estimates of genetic diversity and population stratification, which may aid in future sustainable use of this urchin resource. A total of 22 species-specific microsatellite markers were used for the genetic characterisation of T. gratilla samples from along the South African coast, at Haga Haga, Coffee Bay, Hibberdene, Ballito Bay and Sodwana Bay. A moderate level of genetic diversity was observed, with an average number of alleles of 7.89 and an average effective number of alleles of 6.57, as well as an average observed heterozygosity of 0.55. Population differentiation tests suggest that the geographically representative samples form part of a single, large interbreeding population, with a global Fst estimate of 0.02 (p > 0.05). This finding is likely explained by high levels of gene flow between these locations caused by extensive larval dispersal during the planktonic larval stage. The panmixia observed within these natural populations of T. gratilla indicate that they could be managed as a single genetic stock.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号