摘要:

The migration of elvers ofAnguilla australisRichardson andA. dieffenbachiiGray into Lake Pounui, Wairarapa, was monitored from November 1974 to July 1978 by installing a trap on the outlet stream. The trap was cleared regularly— daily from November 1976 to March 1977—to provide data for a migration periodicity model. The number of elvers caught each season (August‐July) varied from 6754 to 190 009, the largest migrations coinciding with the greatest seasonal rainfall and the smallest migrations with the least rainfall.A. australisdominated all samples: 99.4% of all elvers (n= 372 082) were this species. Glass‐eels (Age Class 0) and Age Class 1 elvers predominated, although relative age class strengths varied considerably between seasons. Most elver activity occurred at dusk and dawn, but movement in daylight was observed during large migrations. Of various meteorological variables considered as possible influences on migration, water level was the most important and affected both periodicity and size of the migration. A delay of several days occurred between the peak water level of a flood and the peak of the following migration; for the mathematical model a delay of 5 days was the most appropriate to explain variations. The water temperature and number of elvers on the preceding day were also incorporated into the final model, which accounted for 76% of the error sum of squares. To test the predicatibility of the model, daily values for water level, water temperature, and the number of elvers for Day 1 were supplied. The resulting series was in good agreement with both the observed and the calculated number of elvers.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515981

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The occurrence of adult quinnat salmon (Oncorhynchus tshawytscha(Walbaum)) in the Rangitikei River, North Island, New Zealand, has been confirmed on several occasions since 1922, but juvenile salmon have not previously been recorded. In late February 1981 a 79‐mm‐fork‐length smolt was caught in a stranded side channel 180 km upstream from the mouth. This suggests that quinnat salmon can spawn successfully in this river.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515982

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

During metamorphosis from ammocoete to macrophthalmia in the southern hemisphere lamprey,Geotria australisGray, 2 blue‐green dorso‐lateral stripes develop along the length of the body. These stripes are retained during the marine parasitic feeding stage and are conspicuous when the adults enter fresh water at the beginning of the spawning migration. They disappear as the upstream migration progresses. The blue‐green coloration is present in the epidermal mucous layer and results from the deposition of biliverdin, a bile pigment produced as a breakdown product of haemoglobin. Liver colour changes during the upstream spawning migration. At the beginning of the migration liver colour is predominantly brown or brick‐red, and livers contain the bile pigment bilirubin. Lampreys collected 50 km from the sea had predominantly green livers owing to the presence of the bile pigment biliverdin, and gonad development had not increased from that observed at the beginning of the spawning migration. Pouched males contained dark green livers with biliverdin as the predominant pigment.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515983

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A key is given to the 17 species of hermit crabs of southeastern New Zealand (Otago region). The key is designed primarily for ecological work and emphasises characters readily seen in living animals still in their host shells. The depth range of each species is also included.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515984

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

In a study of the benthic macroinverte‐brates of 7 small high‐country lakes, 33 species were recorded, with an average of 20.4 species per lake. Groups present in large numbers included oligochaete worms, chironomids, mites, gastropods, and bivalves, with the dominant species typically including most or all of the following:Limnodrilus hoffmeisteri, Aulodrilus pleuriseta, Macropelopiaspp.,Chironomus zealandicus, Chironomussp. a.,Potamopyrgus antipodarum,andSphaerium novaezealandiae.These dominants are similar to those reported from other New Zealand lakes of varied trophic status, this making any designation of trophic state indicators impractical. The distribution and abundance of a few species, particularlyLumbriculus variegatusandLimnodrilus hoffmeis‐teri,correlate with some of the sedimentary parameters measured. Standing crops are large, for example 6761 individuals per m2, 22.93 g m‐2wet weight and 5.60 g m‐2dry weight were found in Lake Grasmere. The relative order in standing crops, viz: Grasmere > Pearson >> Marymere > Lyndon > Sarah > Hawdon >>Letitia, is not consistent with the trophic state order of the lakes. It is suggested that benthic production in the Cass lakes is influenced by the differing supply of allochthonous and autochthonous organic matter and by the relative shallowness of the lakes.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515985

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Seven species ofGonyaulax,2 species ofHeteraulacus,andProtoceratium reticulatumare described from New Zealand coastal waters. Some notes are given on their morphology as seen in the scanning electron microscope.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515986

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A sample survey of 9 thermal pools or streams in 3 Health Districts of the North Island of New Zealand was made over a 15‐month period to determine the presence or absence of pathogenic free‐living amoeba (PFLA) of the generaNaegleriaandAcanthamoeba.Concurrent chemical, physical, and bacteriological analyses of the pools were made.NaegleriaandAcanthamoebawere isolated in the Rotorua and Hamilton Health Districts but not in the Gisborne Health District. Most PFLA were isolated from water with a high coliform content or soil contamination.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515987

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

In June 1979, temperature, salinity, dissolved oxygen, reactive phosphorus, reactive silicate, and nitrate nitrogen data were collected along 3 transects off Cape Foulwind, Greymouth, and Wanganui Bluff west of the South Island. Water entered the study area from the vicinity of the Challenger Plateau. It apparently arrived from the north and northwest, guided by the morphology of the plateau, and turned to flow southwestwards along the continental slope. There is some evidence of recirculation to the north close inshore. These flows appear to contribute to a surface and subsurface temperature maximum parallel to the coast, to a subsurface salinity maximum at least off Wanganui Bluff, to a maximum in the depth of the mixed layer parallel to the coast, and to warm, more saline water with minimum surface reactive phosphorus and silicate concentrations approaching the coast more closely off Greymouth. Freshwater runoff diluted coastal water to the greatest extent off Cape Foulwind and Greymouth. This river water contributed to the levels of reactive silicate since there was a significant negative correlation between salinity and reactive silicate. Upwelling, possibly wind‐induced, brought subsurface water from about 75 m to the surface off Wanganui Bluff, thus raising the inshore temperature, salinity, and dissolved nutrients, and slightly lowering dissolved oxygen concentrations.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515988

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A computer‐based model for forecasting ocean waves in the Southwest Pacific is described. The grid, which represents the sea surface for this model, covers a section of that used in the operational atmospheric analysis and prediction models of the New Zealand Meteorological Service. At each grid point a discrete directional power spectrum is defined. Each component represents an energy density (in frequency and direction) and is treated independently of the others. Propagation of wave energy is effected by a Lax‐Wendroff‐type finite differencing scheme with appropriate modifications near coastlines and grid boundaries. Wave generation and dissipation are calculated using an empirically derived exponential formula. Some examples of results are presented and the hindcasts for selected weather events are discussed. Comparisons between results and visual observations of significant wave height are not very promising but much of the discrepency can be attributed to the scatter of the latter. Some comparisons at the ‘Maui‐A’ site between results from the model and measurements from a waverider buoy show reasonable correlation between significant wave height records. However, this site poses particular problems which are beyond the scope of this type of model.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515989

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor