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1.
于１９９１年４月，从长江口采集葛氏长臂虾标本，实验室进行幼体发育研究，结果表明，幼体自孵出后，在水温２４℃、盐度１２、饵料充足的条件下，有规律的每２天蜕皮１次，共经１１次蜕皮，约２２ｄ完成变态，入仔虾期。  相似文献   

2.
Polychaete assemblages are described from replicate box‐core samples collected in summer 1983 at 18 stations on the continental shelf and upper slope (28–943 m) off the west coast of the South Island, New Zealand, south‐eastern Tasman Sea (c. 41–43°S, 169–172°E). Three main station groupings were identified by multivariate analysis: (1) inner shelf sandy stations characterised by Prionospio australiensis, Aricidea (Acesta) sp., Magelona cf. dakini, Paraprionospio aff. pinnata, Aglaophamus sp., Heteromastus filiformis, and Magelona sp.; (2) middle to outer shelf muddy stations characterised by Levinsenia cf. gracilis, Prionospio australiensis, Paraprionospio coora, Aglaophamus verrilli, and Auchenoplax mesos; and (3) upper slope sandy mud or mud stations characterised by Prionospio ehlersi. A combination of water depth and sediment clay content provided the best correlation with the biotic pattern. Spionidae was the most abundant family (49% of polychaete individuals), which may reflect the scope for opportunistic species in a shelf environment characterised by a high input of terrigenous sediment and episodic upwelling.  相似文献   

3.
Abstract

Polychaetes were collected from eight sites across the Chatham Rise (New Zealand) in the region of the Subtropical Front from water depths of c. 2300 m to 350 m. A total of 169 putative species representing 36 families was identified. Spionidae, Paraonidae, Cirratulidae, Syllidae, and Orbiniidae accounted for 50% of all polychaete individuals. Multivariate analysis revealed that three sites at c. 350–453 m water depth on muddy sand (6–7% clay) shared similar faunal and environmental characteristics. Numerical dominants included Lumbrineris sp., P seudeurythoe minuta, Dipolydora cf. socialis, Aglaophamus verrilli, Prionospio lehlersi, Syllinae sp., Monticellina sp., and Cossura sp. Replicates from a single site at c. 750 m depth on the southern flank of the Rise produced a distinct assemblage dominated by Paradoneis, Naineris, Notomastus, Harmothoinae, Prionospio lehlersi, Levinsenia, Aricidea, Kebuita, Paraonella, and ?Leiochrus species. Replicates from greater depths north and south of the Rise presented a greater range of assemblage characteristics and environmental parameters including temperature, dissolved oxygen, median grain size, calcium carbonate (CaCO3), and total organic matter content. Twenty‐eight taxa were found exclusively below 750 m depths including species of Ampharetinae, Chloeia, Pseudeurythoe, Capitellidae, and Cirratulidae. There was a significant difference in faunal composition between northern and southern flanks of the Rise within depth classes and also between sites at the same depth classes. Faunal density and species diversity appeared highest from the crest to 750 m depth on the southern side. Low species diversity at the deepest sites may be confounded by reduced density.  相似文献   

4.
Two species of benthopelagic calanoid Copepoda, Neoscolecithrix cf. magna (Grice, 1972) and N. ornata n. sp., are described from the upper slope off North Cape, New Zealand. Neoscolecithrix ornata is distinguished from other species of Neoscolecithrix Canu, 1896 s.s. that have a female leg 5 terminal segment with 4 spines (2 terminal and 1 on each border) principally by the transverse row of long, fine spines on the female genital double somite; and by the more squat terminal segment of leg 5 (length/width ratio about 3.7). This is the second time Neoscolecithrix has been recorded from New Zealand. A new genus, Cenognatha n. gen., is distinguished from Neoscolecithrix principally because: rostrum short (bearing 2 filaments); mandibu‐lar gnathobase masticatory margin with slender dorsal spinulose seta; maxilla endite 1 with 5 well‐developed setae, endite 3 without brush‐like sensory seta, endopod usually with 3 long worm‐like sensory setae and 5 brush‐like setae; posterodistal border of basis of legs 1–3 without spines; distal segment of female leg 5 and its basis subequal in length; male leg 5 of similar lengths on both sides (styliform on right), endopod present at least on 1 side, 1‐segmented and spine‐like on right.  相似文献   

5.
Although continental shelf and slope environments typically exhibit high epifaunal biomass and have been subjected to increasing fishing pressure, ecological information on assemblages of non‐commercial invertebrate species from subtidal and bathyal areas remains limited. Sea stars (Echinodermata: Asteroidea), which are known to influence communities through their feeding habits, have received less attention than structural taxa such as corals and sponges. To better understand the ecological roles of asteroids on continental shelves, we investigated ~30 species and assessed their distributions and co‐occurrence with other benthic invertebrates on the shelf and slope of Eastern Canada. Using fisheries data and in situ video footage, we compiled a large dataset covering ~600,000 km2 that included over 350,000 individual asteroid records (37–2243 m depth). Multivariate analyses revealed geographically distinct asteroid assemblages, with a maximal overall density at 400–500 m and the highest diversity at 500–700 m. The most abundant and densely occurring species was Ctenodiscus crispatus. We found that asteroids associate with corals, sponges, bivalves, and other echinoderms, and that depth and substrate influence these assemblages. We identified species likely to affect coexisting organisms by their burrowing behavior that can disrupt epi‐ and infauna (C. crispatus) and through predation on ecologically important corals (Hippasteria phrygiana). In addition to providing baseline distribution and ecological information for many bathyal asteroid species in the Northwest Atlantic, this work highlights the abundance and diversified roles of asteroids within continental shelf and slope ecosystems.  相似文献   

6.
Namalycastis tiriteae, a new species of polychaete (Nereidae: Namanereinae) is described from a freshwater stream in New Zealand. Morphologically it possesses some features intermediate between Namalycastis Hartman and Namanereis Chamberlin as denned by Hartman (1959), but it is placed in the former on the basis of parapodial structure. Notes on physical and chemical conditions in the worm's habitat are also given.  相似文献   

7.
Calorific content was measured in 28 species of New Zealand macroalgae. Values ranged from 1.04 to 3.34 kcal g‐1 dry weight (wt), 3.03–5.18 kcal g‐1 ash‐free dry wt, and 0.13–1.75 kcal g‐1 wet wt. Seasonal variation in calorific content was measured in two of these species, Macrocystis pyrifera and Ulva lactuca, both of which showed clear changes in energy content over a 1‐year period. Factors affecting variation in calorific content between species and during the year are discussed, and the application of the current findings to ecological and aquacultural research on New Zealand seaweeds are considered.  相似文献   

8.
The muscle myogen proteins of 10 species of the family Galaxiidae exhibited a high degree of species specificity when separated by starch gel electrophoresis. Non‐diadromous, non‐lacustrine species had some variation in the proteins present, while diadromous and lacustrine species, except for Galaxias maculatus, had remarkably uniform muscle myogen electrophero‐grams. The variation can be explained by polymorphism and mosaic evolution of isolated freshwater populations. It was found that previously erected specific and generic categories, except for G. vulgaris, are clearly defined by differences in muscle protein. The standardised electropherogram types obtained were subjected to cluster analysis using both squared Euclidean distance and the complement of Jacard's coefficient with average sorting strategy. A principal component analysis was also carried out. The first two components of the principal component analysis widely spaced the three genera included in this study (Salmo, Galaxias, and Neochanna), with N. burrowsius occupying an intermediate position between Galaxias and Neochanna. Previous workers have considered this species to be a connecting link between the two genera. The dendrogram produced by using squared Euclidean distance (which included all available information) first clustered the types into Salmoniidae and Galaxiidae. The latter were split into the genus Neochanna and the genus Galaxias which was then subdivided into stout‐bodied species (G. argenleus and G. jasciatus) and slender‐bodied species. G. brevipinnis and G. vulgaris types were further separated from the three alpine Galaxias species and G. maculatus. The substantial agreement of these results with previous taxonomic efforts indicates that electrophoretic data can be a valid taxonomic tool.  相似文献   

9.
Marine sediments in continental shelf ecosystems harbor a rich biodiversity of benthic communities. In this study, the spatial and temporal diversity and community assemblages of free‐living marine nematodes were studied by sampling at six depths and over 3 years from the southwest continental shelf off Bay of Bengal, one of the least explored tropical shelf ecosystems. The dominant marine nematode species were related with abiotic variables as part of this study. The effects of sediment granulometry generally decreased with increasing depth and the highest nematode density and species diversity were recorded on coarse sand (shallower depths). Multivariate analysis of the nematode community data showed that community structure differed significantly among depths as well as among years. Statistical analyses showed significant correlations between the nematode community and abiotic variables. Sediment texture, organic matter, water pressure and depth profile were crucial factors for determining diversity, vertical profile and feeding types of the nematode community. Other environmental factors, including anthropogenic pressure, did not have an effect on nematode diversity except for the presence of some tolerant species (Metachromadora spp., Sabatieria spp. and Siplophorella sp.). This study represents a baseline of knowledge of free‐living marine nematode communities that can be used in the future to compare nematode assemblages from temperate shelf ecosystems.  相似文献   

10.
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11.
Many species from the family Poeciliidae have been transported around the world by the aquarium trade, often establishing populations in areas far outside their natural range. The one‐spot livebearer, Phalloceros caudimaculatus is one such poeciliid species. In March 2002, a nonindigenous population of P. caudimaculatus was discovered at Collaroy, in the Sydney metropolitan area, the first record of this species in eastern Australia. Following this discovery, electrofishing and light‐trap surveys were conducted at the site, and dip‐netting and visual surveys were conducted in surrounding water bodies. P. caudimaculatus was widespread and abundant at the Collaroy site, but no further populations were discovered. Another pest poeciliid species, Gambusia holbrooki, originally present at the site, was absent and, although the mechanism remains unclear, may have been displaced by P. caudimaculatus. Both P. caudimaculatus and G. holbrooki share the characteristics of successful invasive species, with extremely broad physical tolerances and high reproductive outputs. Given the well‐documented negative ecological effects of poeciliids, especially G. holbrooki, we recommend that a precautionary approach should be adopted for the management of P. caudimaculatus and its eradication from the site be attempted.  相似文献   

12.
The analysis of 79 hauls performed by commercial bottom trawlers from 50 to 800 m depth in the Balearic Sea (north-western Mediterranean) from June 1995 to September 1996 yielded a total of 30 cephalopod species belonging to 12 families. Cluster analysis of these data gave as a result two main groups 50–200 m and 200–800 m each subdivided into two other groups (50–100 vs. 100–200 m and 200–600 vs. 600–800 m). These results suggested the existence of two assemblages that could be associated to the continental shelf (50–100 m) and the upper slope (600–800 m) separated by a wide transitional zone (100–600 m) representing a region of overlapping shelf and slope faunas (ecotone). The faunistic bathymetric gradient showed a continuous substitution of species with depth rather than discrete assemblages separated by distinct boundaries. The more coastal species such as Eledone moschata, Loligo vulgarisSepia officinalis and Octopus vulgaris were found on the continental shelf; on the transitional zone, apart from species characteristic of this zone (Illex coindetii, Sepietta oweniana, Rossia macrosoma, Scaeurgus unicirrhus and Pteroctopus tetracirrhus), we also observed species from both the continental shelf and slope. The upper slope was characterized by typical species of deeper waters, such asBathypolypus sponsalis , Histioteuthis reversa, H. bonnellii, Ancistroteuthis lichtensteinii andOnychoteuthis banksii . The octopod O. vulgaris was the dominant species on the continental shelf and upper transitional zone, being substituted by T. sagittatus on the lower transitional zone and upper slope. Mean biomass decreased abruptly from the continental shelf to the transitional zone and from there to the upper slope. Mean species richness and species diversity were higher in the transitional zone than in the continental shelf and upper slope. Finally, some biological aspects of the more abundant deep-sea cephalopod species are studied: Bathypolypus sponsalis, Octopus salutii,Pteroctopus tetracirrhus , Histioteuthis reversa and H. bonnellii.  相似文献   

13.
The male of Doropygus platylhorax Jones, 1974 and two new species of Doropygus (D. louisae and D. spinosus) are described and illustrated. The specimens of Doropygus described by Schellenberg (1922) as D. pulex are assigned to the new species D. louisae. Specimens of Ophioseides (Scolecimorpha) joubini described by Schellenberg (1922) have been re‐examined together with fresh material, and have been described as a new species, Ophioseides schellen‐bergi.  相似文献   

14.
Plaxiphora boydeni n.sp. from wave‐exposed rocky shores of southern New Zealand is described and illustrated. This is the first published record of the genus from the New Zealand mainland. P. boydeni is readily distinguished from the 2 other New Zealand species of the genus, which occur in the subantarctic region, by the absence of bristle‐tufts on the girdle.  相似文献   

15.
The diets of eight demersal fish species from the upper continental slope (c. 24CM‐50 m) were determined from samples taken during late January and early February 2004, off the Wairarapa coast, North Island, New Zealand. Diets were from a combination of benthopelagic and benthic sources, with most species exhibiting ontogenetic shifts in diet, in that larger‐bodied food (fish and/or natant decapod prawns) was more important in the diets of larger fish. Javelinfish (Lepidorhynchus denticulatus), silver roughy (Hoplostethus mediterraneus), and capro dory (Capromimus abbreviatus) had predominantly benthopelagic diets, whereas the diets of sea perch (Helicolenus percoides), Bollons’ rattail (Caelorinchus bollonsi), two‐banded rattail (C. biclinozonalis), and silverside (Argentina elongata) were predominantly benthic, with the crab Carcinoplax victoriensis an important food item. The diet of Oliver's rattail (C. oliverianus) was a mix of benthopelagic and benthic organisms. Generally, levels of dietary overlap between the eight species were low. Overall, the diets of these fish probably reflect regional and seasonal levels of food availability. Notes on food observed in the stomachs of a further 18 species, for which there were fewer than 10 stomach samples per species are also provided.  相似文献   

16.
Drifting mysids were sampled to determine diel activity, and whether mysid numbers vary with respect to inflowing and outflowing tides. Samples of drifting mysids were collected at the mouth of the Taieri River, New Zealand, over one 24‐h cycle using five replicate conical drift nets in January 1999. One‐night and 1‐day ebb and flood tide were each sampled. Four species of mysid Tenagomysis macropsis, T. novae‐zealandiae, T. robusta, and an apparently undescribed species of Gastrosaccus sp., were collected over the sampling period. One species, T. robusta, has not previously been collected from estuarine or riverine systems. The undescribed Gastrosaccus sp. was the most abundant of the four species. All four species were more abundant at night, with T. robusta and Gastrosaccus sp. being considerably more abundant in the drift on outflowing tides. In contrast, roughly equal numbers of T. macropsis and T. novae‐zealandiae were observed drifting in and out of the estuary at night.  相似文献   

17.
The oxygen (δ18O) and carbon (δ13C) isotope ratios of 10 species of living Bryozoa collected from the Otago Shelf, New Zealand were analysed to assess the extent to which isotopic equilibrium (relative to inorganic equilibrium isotope fractionation) is attained during the precipitation of skeletal calcium carbonate. The data reveal that whereas eight species of Bryozoa synthesise skeletal carbonate in apparent oxygen isotope equilibrium with respect to environmental conditions, two species (Celleporina grandis and Hippomonavella flexuosa) yield δ18Ocalcite values which indicate significant disequilibrium oxygen isotope fractionation during calcification. Sufficient data are available from one species (C. grandis) to demonstrate that disequilibrium is probably related to kinetic factors associated with diffusion‐controlled transport of HCO3‐ to the site of calcite precipitation. Carbon isotope signatures indicate significant departures from inorganic isotope equilibrium in all but one bryozoan species (Hippomenella vellicata). Although greater uncertainties are associated with estimates of the isotopic composition of total dissolved inorganic carbon (δ13CSDIC), the data suggest that two factors—kinetic fractionation and incorporation of respiratory CO2—are important in controlling carbon isotope disequilibrium. Where bryozoan species exhibit evidence for disequilibrium in both oxygen and carbon isotope systems (C. grandis, H. flexuosa), it is likely that kinetic factors are primarily responsible for observed departures from carbon isotope equilibrium. In contrast, the probable explanation for those species which display evidence for carbon isotope disequilibrium only, is that skeletal carbonate is precipitated from a DIC pool modified by the incorporation of respiratory CO2. Differences between the carbon isotope composition of skeletal elements from the same species and co‐existing species living in the same community suggests that significant variations may occur in the extent to which marine DIC and respiratory CO2 are utilised during calcification. Additional studies of carbon pathways associated with calcification are required to assess the relative effects of kinetic, metabolic, and environmental factors on the carbon isotopic composition of bryozoan skeletal carbonate.  相似文献   

18.
In 1994 a major biotoxin event occurred along the east coast of the South Island, New Zealand. Gymnodimine, a unique bioactive spiroimine, was isolated and characterised from Foveaux Strait dredge oysters (Tiostrea chilensis = Ostrea chilensis) collected during this outbreak. This study reports the results of liquid chromatographic‐mass spectrometric analysis for gymnodimine in 217 samples from eight species of shellfish over the years 1993–99. Of these samples 155, covering six species of shellfish, contained detectable gymnodimine with a range in concentration from 14.8 to 23 400 μg/kg. Gymnodimine‐containing shellfish occurred at 37 of the 63 sites sampled from around New Zealand. This study demonstrates that accumulation of gymnodimine is not limited to T. chilensis and can occur in other shellfish species over much of New Zealand. Gymnodimine is a possible cause of the numerous historical biotoxin screen‐positive results.  相似文献   

19.
Three new species of calanoid copepod in the family Aetideidae are described, two in Aetideopsis Sars, 1903 and the third in Bradyidius Giesbrecht, 1897. One Aetideopsis species is from off South West Africa (south‐east Atlantic), the remaining species are from the east coast of New Zealand (south‐west Pacific). The genus Pseudaetideus Wolfenden, 1904 is merged with Aetideopsis.  相似文献   

20.
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