摘要:

Fishes were observed and collected at the Kermadec Islands in 1984 and 1985. Five families and 16 species were newly recorded from the New Zealand region and a further 18 species were newly recorded from the Kermadec Islands. The number of coastal fishes known from the Kermadec Islands is now 112. Seventy‐seven coastal fish species were classified into five abundance classes at five Kermadec Islands localities; 27 showed north‐south abundance trends. Of the 112 Kermadec Islands species, 55% are found in temperate New Zealand, but only 20% are common there. The fish fauna at the Kermadec Islands has greater affinity with that at Lord Howe Island (64%) and also has significant links with Rapa and Easter Islands (both 22%) which are at similar latitudes in the eastern Pacific Ocean. Two (possibly three) coastal fish species are endemic to the Kermadec Islands.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516194

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The growth of landlocked sockeye salmon in the Waitaki lakes, New Zealand, was studied from 1975 to 1984. Age and growth were determined by length frequency analysis and by back calculation of growth from annual rings laid down on otoliths and scales. Growth was also determined for fish reared at three hatcheries. Salmon resident in Lake Ohau, a large deep oligotrophic lake, grew relatively slowly. Mature fish from two to five years of age averaged 182, 224, 263, and 329 mm in length, respectively. Growth was more rapid in Lakes Benmore, Aviemore, and Waitaki, which are relatively shallow and productive hydro‐electric storage reservoirs. In Lake Benmore, mature fish from two to five years of age averaged 243, 288, 352, and 450 mm in length, respectively. Fish reared in hatcheries grew faster than in the wild with some averaging 382 mm at two years of age. Food supply was considered to be the principal factor influencing growth rates. The fish originated from anadromous ancestors in the Frazer River, Canada, and have been resident in fresh water in New Zealand for about 18 to 25 generations; they retain the capacity for rapid growth in favourable environments.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516195

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Plasma concentrations of throxine (T4) in chinook salmon,Oncorhynchus tshawytscha, rearing at a New Zealand salmon hatchery, were measured by radioimmunoassay. Blood samples for assay were collected at approximately weekly intervals during the period February‐August (southern late summer‐winter). Plasma T4levels varied in a cyclical fashion, with maximum concentrations occurring near the time of each new moon. Within the lunar month, the mean date of the recorded T4peak was at 6.4 + 3.9 days before new moon (95% confidence level). Since thyroid hormones have been implicated in the process of salmonid smoltification, we suggest that the planning of hatchery release times for chinook salmon should include a component which takes account of the apparent link between lunar phase and circulating T4levels in these fish.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516196

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The instream flow incremental methodology predicts the potential amount of habitat in a stream, rather than fish biomass or numbers. We introduced rainbow trout into stream channels next to the Waitaki River, South Island, New Zealand, and subsequently maintained a constant flow in these streams. The biomass of rainbow trout in individual riffles and pools of the streams was determined and related to the amount of usable area in these habitats calculated using the incremental methodology. Regardless of fish stocking density, rainbow trout biomass in late summer and early winter was not correlated with the amount of usable habitat. Users of the incremental methodology should realise that the method cannot be expected to predict fish biomass or numbers when fish are not limited by the amount of space available to them. When fish are food‐limited, as apparently occurred in our streams, relationships between usable area, fish food organisms, and fish biomass must be understood before one can predict flow change impacts.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516197

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Six fish collected from an ornamental pond in Tauranga were identified as hybrids between koi(Cyprinus carpio)and goldfish(Carassius auratus)by using meristic, morphometric, and electrophoretic characters. The hybrids were intermediate between koi and goldfish for the number of lateral line scales, the shape of the pharyn‐geal teeth, and the presence of a pair of reduced posterior barbels. At fifteen diagnostic enzymatic and protein loci which distinguish koi and goldfish, the hybrids appeared as heterozygotes. The close similarity of the six fish in meristic, morphometric, and electrophoretic characters suggests they were derived from the same parents.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516198

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

After exceptionally heavy rainfalls and associated land movements in July 1985, sediment inflow into Lake Tutira, Hawke's Bay, New Zealand, caused a five‐fold reduction in the depth at which 5% of the surface photosynthetically active radiation remained. Light level reduction was associated with increased nephelometric turbidity caused by the suspended sediment. The decreased light levels, as monitored by measurement of the vertical attenuation coefficient of light in the lake, persisted for about three months and were accompanied by a marked reduction in the lower depth limit of aquatic macrophytes: from 6.7 to 1.8 m forElodea canadensis, and from 4.6 to 1.8 m forHydrilla verticillata. As water quality returned to its pre‐storm condition, these species regrew very rapidly in the denuded areas from surviving rhizomes.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516199

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

No significant differences in appetite (used here in the sense of amount of food consumed over any given 24‐hour period) were found between crabs starved for 28 days and crabs freshly caught from the sea when fed to satiation over a 13‐day period. Crabs from these two feeding history treatments also exhibited the same level and rate of appetite depression. Longer periods of feeding depressed appetite still further. Although feeding may only minimally influence appetite over any two‐ or three‐day time span, feeding to satiation over 13 consecutive days significantly depressed appetite. Experiments, using the predatory crabOvalipes catharus, tested the effectiveness of starvation for standardising appetite. Individual appetites were highly variable and were not standardised by up to 21 days starvation. At temperatures above 15 °C,Paphies subtriangulataandCallianassa filholiwere either cleared from the foregut or were unrecognisable within 6 hours. However, at about 10 °C, these prey could take up to 21 hours to be cleared. Shell fragments were cleared from the foregut by regurgitation after virtually all soft parts had been digested. As crab size increased, crabs were more efficient at ingesting food, took longer to empty a full foregut, and had faster absolute rates of foregut clearance. The upper limit of food intake was determined by foregut volume which was logarithmically related to carapace width. This relationship explained a positive relation found between appetite and carapace width.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516200

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The larval shell development ofPaphies subtriangulatais described from larvae reared to settlement in the hatchery. Externally the larval shells ofP. subtriangulataare very similar to thoseof Paphies ventricosaand, to a lesser extent,Paphies australis. Internally the hinge structures of the late‐stage larvae ofP. subtriangulata, P. ventricosa, andP. australisare sufficiently different to distinguish the species. The spatulate tooth and the peg toothof P. ventricosaare absent inP. subtriangulataandP. australis;the ligament ofP. australisis posterior to the provinculum and central inP. ventricosaandP. subtriangulata. Straight‐hinge stage larvae ofP. subtriangulatawere 88–143 μm long and 67–117 μm high and umbo stage larvae were 125–265 μm long and 97–223 μm high. The larvae settled in about 17 days from a length of 230 μm.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516201

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In February 1982 there was an intense bloom of dinoflagellates close inshore off West‐land, New Zealand, and dinoflagellates also formed a large proportion of the phytoplankton offshore. Diatoms were present only at the bottom of the photic zone inshore off Wanganui Bluff, where dissolved nitrate‐nitrogen levels were elevated. Most biomass and production parameters were at least twice as large as in winter except for offshore biomass which was larger in winter. Weighted average chlorophyllaconcentrations were negatively correlated with the depth of the mixed layer. The relative contribution which the vertical distribution of chlorophylla, the production per unit chlorophyllaat optimal light intensities, and the initial slope of the light saturation curve made to the relationship between water column production per unit chlorophyllaand incident solar irradiance in inshore and offshore waters is discussed. In the non‐senescent inshore populations dominated byProrocentrum micans, 91% of the variance in water column PBwas explained by variance in incident solar irradiance with a light utilisation index of 3.00 g C (g Chl.a)‐1E‐1m2.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516202

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The standing crop and succession of marine microalgae are described for blooms in the surface water of a tide crack in the permanent ice of the Ross Ice Shelf at White Island, McMurdo Sound, Antarctica. The dominant microalgae during late November were Chlorophyta (Pyramimonassp.). Bacillariophyceae (diatoms) were dominant from early December until the end of the study in late January. Five species were most abundant:Nitzschia cylindrus, Nitzschia curta, Nitzschia obli‐quecostata, Fragilariasp., andSynedra tabulata. The concentration of chlorophyllawas at the highest level (30.0 μgl‐1) whenPyramimonassp. were most abundant. Incident light and the percentage transmission of light to a depth of 1 m in the tide crack were also at maximum levels at this time. The chlorophyllaconcentration decreased to below the limits of detection after the thaw in mid‐January when there was an abrupt increase in the temperature and a decrease in the salinity of the surface waters in the tide crack. The concentration of dissolved oxygen was at a maximum when the diatoms were most abundant.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516203

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor