摘要:

An otariid skull from the Middle Pleistocene of Ohope Beach, North Island, is described as a new species,Neophoca palatina.The wide interorbital region is the main character that suggestsNeophoca,butN. palatinadiffers from the extantN. cinereain the smaller alveoli, wider palate and basioccipital, and a difference in the shape of the bulla.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515990

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The gut contents of 50 species of fish that inhabit coastal rocky reefs of north‐eastern New Zealand were examined. Most of the fish were collected in the vicinity of Goat Island, north of Auckland, by spearfishing, handlines, and rotenone. Food items in the gut were analysed by both percentage occurrence and percentage volume for each species. Their feeding habits are briefly described. An index of use(U),based on the intensity of predation and the number of fish taking the food, was calculated for each food type. The most important foods of rocky reef fishes (U≥0.1) were amphipods, crabs, fishes, gastropods, copepods, errant polychaetes, hermit crabs, and small bivalves. Most rocky reef fishes have broadly generalised feeding habits, and foods taken mainly reflect those organisms of suitable size that are abundant and most readily available. Notable exceptions are sponges, hydrozoans, anthozoans, bryozoans, and ascidians, which, although common, are probably largely unpalatable to fishes. Fishes appear to dominate the carnivore trophic levels of rocky reef communities: 44 species (88%) are carnivores; 1 species (2%) is omnivorous; and 5 species (10%) are herbivores. In terms of biomass, however, herbivorous fishes may comprise a significant proportion of the total standing crop of fishes and their impact on the reef community may be as great as that of invertebrate‐feeding carnivores.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515991

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The life history of the endemic New Zealand freshwater shrimpParatya curvirostris(Heller, 1862) (Decapoda: Atyidae) in 3 streams in North Canterbury is described. Each female carried on average 2000(±634) eggs and incubation took about 28 days at 14–18°C. Mixohaline planktonic larvae were found in the Ashley Estuary and in small numbers in fresh water. Post‐larvae had a carapace length of 0.5–1.5 mm, and most developed into males which occurred in freshwater streams. At a carapace length of 5.0–6.0 mm males developed into females which could be ovigerous at any time of year and could bear several successive broods. Estimated growth rate was greatest from late winter to early summer with a maximum weekly rate of 1.5 mm carapace length calculated in spring. The behaviour of a female during egg hatching is described in detail.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515992

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Mounds of ‘coral’ off Separation Point, Tasman Bay, which have recently been protected to conserve ecologically associated commercial fish species, are predominantly growths of Bryozoa. Two species(Celleporaria agglutinans, Hip‐pomenella vellicata)make up the bulk of these structures. Trawling through the ‘coral’ grounds has affected the fish populations to the extent that an area has been closed to trawling to conserve stocks.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515993

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The mucilage‐producing colonial form ofPhaeocystis pouchetii(Hariot) Lagerheim is recorded in New Zealand for the first time. These non‐motile colonies have been cultured from the 1981 “Tasman Bay slime” in filtered seawater medium enriched with soil extract and vitamins. Massive occurrence of the mucilage‐producingPhaeocystiscolonies in association with other phytoplankton is suggested to be the cause of the “Tasman Bay slime” outburst in spring 1981.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515994

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The Waikato River originates in oligotrophic Lake Taupo, but becomes chemically enriched before reaching Lake Ohakuri, where phytoplankton increases dramatically. Data were collected over 2 years, including daily measurements for 1 year of N, P, Si, and chlorophyllain water leaving the lake. The hypolimnion remained stagnant in summer, and inorganic‐N peaked after lake overturn. NO3‐N showed a marked seasonal cycle in concentration and total flux in water leaving the lake, which may not correspond with input rates from the catchment.Melosira granulatavar.angustissimadominated the phytoplankton in summer, andChlamydomonasspp. andCyclotellaspp. in winter. In summer, weekly cycles in algal abundance, which correlated inversely with NO3‐N and DRP concentrations, were dictated by weekly flow cycles resulting from the requirements of hydro‐electric power generation. Flow rate and temperature appear the dominant factors regulating phytoplankton abundance. Shorter residence time and probably slower growth rates in winter, and longer residence and more rapid growth in summer interact critically. Phytoplankton production in river lakes such as Ohakuri with a brief water residence time is more appropriately represented by the mass flow of algal material through it than by the abundance of the standing stock. Summer phytoplankton biomass in Lake Ohakuri is equivalent only to a mildly eutrophic condition, but the amount generated and then lost from the lake is equivalent to production in a lake of much higher trophic status in a closed basin.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515995

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Lake Rotoma is a deep (70–80 m), oligotrophic, warm monomictic lake of volcanic origin with insignificant stream inflow and no clearly defined outflow. For at least 60 years up to 1972 the lake level fluctuated markedly about an overall rising trend of some 6–10 m. Nearshore profiles are related to the prevailing wave climate superimposed upon the overall rising lake level, shelves being wider, less steep, and deeper about the more exposed eastern and southern shorelines. The outer portions of shelves extending well below modern storm wave base into waters as deep as 15–25 m are relict features from lower lake level stands. Sediments fine from sand‐gravel mixtures nearshore to silts in basinal areas. Their composition reflects a composite provenance involving the lavas and tephras about the lake, as well as intralake diatom frustules and organic matter. The distribution pattern of surficial bottom sediments is an interplay between grains of both biological and terrigenous origin, supplied presently and in the past by a variety of processes, that have been dispersed either by the modern hydrodynamic regime or by former ones associated with lower lake levels. These interrelationships are structured by erecting 5 process‐age sediment classes in the lake, namely neoteric, amphoteric, proteric, palimpsest, and relict sediments, analogous to categories postulated for sediments on oceanic continental shelves. Short‐core stratigraphy includes the Kaharoa (A.D. ∼ 1020) and Tarawera (A.D. 1886) tephras. The rates of sedimentation of diatomaceous silts in basinal areas have more than doubled since the Tarawera eruption, indicating an overall increase in the fertility level of lake waters associated, perhaps, with recent farm development in the catchment.

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515996

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1983.9515997

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor