摘要:

The basic acoustical methods for estimating the volume backscattering strength and the absolute biomass density are commonly known. However, the detailed techniques for minimising errors in fitting the calibrated parameters of an echo sounding system in these computations are still not adequately examined and discussed. This paper describes and discusses the following computing techniques involved in the absolute biomass estimation: (i) the fitting of the calibrated time varied gain (TVG) curve, the selection of its operating interval, and the correction of its response; (ii) the compensation for the limitation of the signal bandwidth; (iii) the computation of the equivalent beam width of a transducer using its calibrated beam patterns; and (iv) the accuracy in the conversion from the volume backscattering to the absolute fish density using individual fish target strength measurements.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516204

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

An analysis of protein variation at three loci (transferrin, guanine deaminase, and an esterase) in sets of blood samples taken from single schools over four years off the coast of New Zealand is reported. There were no significant variations in allele frequency between sample sets for transferrin. The esterase data were heterogeneous, showing significant within‐ and between‐year variations in allele frequency. Esterase allele frequencies changed with the average size of fish in the school. There was no difference between the estimated esterase allele frequencies of eastern and western coast schools. In most cases the esterase and guanine deaminase allele frequencies observed were similar to those found for schools in tropical waters to the north of New Zealand. However, some schools had frequencies similar to those of schools from French Polynesia and others similar to those from schools from Papua New Guinea and the Solomon Islands. The results obtained are considered in the light of various discrete stock models and an isolation‐by‐distance model of the Pacific skipjack tuna population.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516205

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Bacteria and bovine faecal matter were introduced into cultures of pathogenic free‐living amoebae, with chlorine or chlorine dioxide. The bacteria and faeces were to simulate natural conditions for a more exacting test of disinfectant demand when compared to axenic conditions. Both chlorine and chlorine dioxide were effective disinfectants under all conditions tested. Axenically and monoxenically cultured amoebae were used, the latter exerted a greater disinfectant demand.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516206

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Non‐tidal daily mean currents on the south‐west flank of Kahurangi Shoals are strongly correlated with the local alongshore wind. A correlation equation was established which accounted for 71% of the variance in the non‐tidal flow. This equation also provides realistic estimates of the surface and bottom drag coefficients. Upwelling is prevalent along the north‐west coast of the South Island. Under northwards directed alongshore winds in mid March 1983 a plume of cold, saline, nutrient‐rich water moved northwards and offshore from north of Kahurangi Point. Warm, less nutrient‐rich water moved south from near Cape Farewell between the coast and the plume. A prominent front was developed between these two waters. The plume water in western Cook Strait met the water from the East Cape Current in a subsurface front. The Kahurangi plume can have patches of minimum‐temperature water embedded in it. The spacing of about 20 km between patches is consistent with daily modulation of the plume.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516207

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A new lemaeopodid copepod gill parasite of the tarakihiCheilodactylus macropterusis described from two locations around New Zealand. It is distinguished from the other species ofAlellaon the basis of the armament of the first maxilla and the second antenna. Of 300 tarakihi collected from the Canterbury Bight, New Zealand, 21 fish, all less than 27 cm fork length and less than five years of age, carriedAlella tarakihin. sp. and a further three copepod specimens were obtained from 427 host fish from Tasman Bay.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516208

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Calamoecia lucasiwas found withBoeckella propinquain the Kaihoka Lakes, Nelson, andBoeckella hamatawithBoeckella triarticulatain Lake Elterwater, Marlborough. These are the first records ofC. lucasiin the South Island, New Zealand, and ofB. hamataco‐occurring withB. triarticulata.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516209

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A method is described that enables determination of the head capsule width ofDeleatidiumspp., from labia length measurements only. This method has proven useful for gut analysis of recently emerged chinook salmon(Oncorhynchus tsawytscha)of fork length 29–34 mm.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516210

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The behaviour of male New Zealand fur seals(Arctocephalus forsteri)was observed at a non‐breeding colony during the winter. Seals spent less time lying and more time interacting socially, moving about, and engaged in comfort behaviours, than they do during the breeding season. Lying behaviour was more likely to occur during the afternoon, and was most prevalent when there was little cloud or wind. By contrast, seals were most active in the mornings (social interactions and comfort behaviours), and under cloudy (social interactions) and windy conditions (moving about). We suggest that the activity of the seals was, at least in part, a thermo‐regulatory response to the prevailing environmental conditions, allowing them to avoid overheating while on land.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516211

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Seventeen demersal fish species collected during a commercial line fishing trip off northern New Zealand are listed together with data on abundance, location, and habitat. These are the first records for the area; 15 are the most northerly records for the species and major range extensions are recorded forCentroscymnus owstoni, Deania calcea, Etmopterus lucifer, Pseudophycis barbata, andHyperoglyphe antarctica. A prespawning aggregation of ling,Genypterus blacodes, is recorded for the first time from this region.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516212

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor