摘要:

The lightly exploited populations of tarakihiCheilodactylus macropterusoff the west coast of the South Island and off the Chatham Islands were sampled for age and growth in 1971 and 1972. The lengths‐at‐capture showed similar growth curves in both areas, a major feature being a rapid decline in annual length increment after year 10 (mean length at that age is 38–39 cm). Both populations contained a large proportion of fish older than 10 y. A rapid decline in annual length increment after year 10 has not been observed in the heavily fished tarakihi stock off East Cape and may be characteristic of lightly exploited populations. The age composition of the Chatham Islands tarakihi indicated that this stock has been subject to fluctuations in recruitment and thatMwas of the order of 0.08. In the lightly fished stock off the west coast of the South Island,Zwas approximately 0.13 soFwas there possibly of the order of 0.05(Z, F, andMare the instantaneous rates of total, fishing, and natural mortality respectively).

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515658

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Estimates of the population and standing cron of fishes were made in six selected transect areas around Goat Island (174° 47’ 50” E, 36° 16’ 10” S), a typical rocky reef area on the coast of north‐eastern New Zealand. There were considerable differences in the numbers of species and individuals between the sampling areas. Chance encounters with schools of “transient” fishes was a major source of variation between, replicate censuses. Amongst the “resident” species, variation in numbers could be attributed to habitat differences. Bottom topography and algal cover are important factors affecting the distribution and abundance of reef fishes. Standing crop estimates of resident fishes ranged from <0.001 kg.m−2(low relief bottom, sparse algal cover) to 0.103 kg.m−2(high relief bottom, extensive algal cover). These figures are similar to those obtained for Californian kelp beds and. for coral reefs. Reef fish .populations are susceptible to exploitation and the scarcity of larger fishes in two of the study areas could be attributed to spearfishing. Resident species are most vulnerable to spearfishing, and legal protection for these fishes is suggested.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515659

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The seasonal reproductive rhythm of the snapperChrysophrys auratus(Forster), was studied from November 1973 to April 1975. Methods used were to analyse gonad maturity stages, gonad weights, and ovarian egg sizes. The histology of the gonads was also studied.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515660

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

During summer, upstream migrations of juvenile freshwater eels (elvers) of both species(Anguflla australis schmidtiiPhillipps, the short‐finned eel, andA. dieffenbachiiGray, the long‐finned eel) are observed at hydro‐electric dams and waterfalls. The migration was sampled at Karapiro Dam on the Waikato River, 1970, 1971, and 1974, and samples from a further 11 areas throughout the country were analysed.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515661

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Aquatic macrophytes(Elodea canadensisRich, in Michx.,Lagarosiphon major(Ridley) Moss.,Potamogeton crispusL.,Potamogeton ochreatusRaoul,Pota‐mogeton cheesemaniiA. Cunn., andMyriophyllum elatinoidesGaud.) were collected from Lakes Rotoaira, Taupo, and Aratiatia, North Island, New Zealand, in November 1972 and analysed for 26 elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, sodium, chlorine, silicon, aluminium, iron, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, molybdenum, strontium, barium, lead, boron, gallium, and zirconium).ElodeaandLagaro‐spihonwere sampled again in March 1973, July 1974, and August 1974, to provide data on variability within a single stand, and change in element content during different seasons and different stages of growth. Surface water, plankton, and sediment samples were also collected at each sampling site in November 1972 and were analysed for the same range of elements.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515662

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Temperature and salinity observations were made over tidal or half‐tidal periods between 26 February and 1 March 1971 at four stations in Tasman and Golden Bays, and surface and bottom currents were measured. Further temperatures and salinity data were obtained near the head of Tasman Bay between December 1971 and January 1973.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515663

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Sampling of 57 littoral stations in Manukau Harbour, Auckland, (37° 02’ S, 174° 41’ E) for species composition, distribution, and abundance as part of a base‐line ecological survey of the harbour shows that the community trophic structure is related to the sediment grain size. Deposit feeders such as the bivalvesMacomona lilianaandNucula hartvigianaand the gastropodZeacuman‐lus lutulentusare most abundant in fine sand, whereas suspension feeders such as the bivalvesChione stutchburyiandPaphies australeare most abundant in medium sand. The proportion of deposit feeders in the sample increases with decreasing grain size of the sediment. Most stations conform to this general trend, although when the results are plotted as the percentage of deposit feeders against the median and mean grain sizes of the sediment in which they occur, three groups of stations appear anomalous. These stations, at Waiau Pa, Pollok Beach, and Fosters Bay, may be unstable and undergoing a change in community structure or sediment characteristics. Identification of unstable areas using this method may be useful to monitor effects caused by environmental changes.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515664

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

In laboratory experiments,Pleurohranchaea novaezelandiaeCheesoman (Mollusca: Gastropoda) readily ate juvenile and adultActinia tenebrosaFarquhar (Cnidaria: Anthozoa). Invertebrate predators such asP. novaezelandiaemight effectively determine the lower limit of the zone occupied byA. tenebrosa, by eating those individuals which are found below about low water of neap tides.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515665

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

The quantitative distribution ofTemora turbinatain summer appears to be governed in the New Zealand region by subtropical currents and by its nutritional requirements. The existence ofT. turbinataprincipally in coastal waters suggests that threshold nutritional conditions exist beneath which this species cannot breed.Temora turbinataapparently attains very large numbers only in enclosed or semi‐enclosed bodies of water, where wholesale exchange of local water with adjacent water does not take place. Australian and New Zealand populations may be kept mixed by the introduction of animals from the Australian coast in the meandering zonal jet which leaves the East Australian Current at about 34° S.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515666

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Post‐planktonic development ofPinnotheres novaezelandiaeinPerna canaliculusfrom Wellington Harbour was found to be similar to that of the other members of the Pinnotheridae. The invasive stage was not found. The sequence of stages found within mussels was an unknown number of pre‐hard stages occurring in both sexes, then a hard‐shell stage; the males show no further morphological changes after this point, but the females mature through a further four soft‐shell developmental stages. No similar post‐hard soft stage occurs in males, although previous workers reported it in maleP. pisum.

ISSN:0028-8330    

DOI:10.1080/00288330.1977.9515667

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor