摘要:

Hapuku(Polyprion oxygeneios)were tagged in south‐east South Island (SESI), Cook Strait (CS), and Poor Knights Islands (PKI), New Zealand, to determine their movements. 1623 fish were tagged and the overall recapture rate was 16.3%. Some hapuku were recaptured from the tagging sites (SESI 13%, CS 39%, PKI 40%), often after long periods at liberty, whereas others travelled substantial distances. The greatest distance travelled was 1389 km (by two fish) and the maximum period at liberty was 10.2 years. SESI hapuku tended to migrate northwards towards CS. The median distance travelled increased with hapuku length at recapture, suggesting that maturation and spawning stimulate migration. However, some of the smaller, immature hapuku also travelled several hundred kilometres. CS hapuku appeared to travel much shorter distances than SESI hapuku, but this may have been an artifact of the lower hapuku fishing effort outside the CS‐Kaikoura region.PKIhapuku showed very limited movements, and no interaction with CS or SESI fish. The results are consistent with the presence of a single stock in the SESI‐CS region, and possibly a separate stock in northern New Zealand.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516852

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Two new species of benthopelagic calanoid Copepoda are decribed from Evans Bay, Wellington Harbour, New Zealand. The speciesStephos hastatusn. sp. andS. angulatusn. sp. (Family: Stephidae) are the first records of this family and genus from New Zealand.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516853

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

During the period March 1985 to January 1997, 3950 school sharks,Galeorhinus galeus(L), were tagged, mostly opportunistically during other research activities. Up to July 1997, 207 sharks had been recaptured. The best recovery rates were from sharks tagged with internal (8.8%) and dart (6.5%) tags and first caught by line methods (22%). The maximum distance travelled was 4940 km, the maximum time at liberty was 3505 days (9.6 years), and greatest average speed was 22.8 km/day. Most sharks (76%) moved less than 500 km, but the larger movements included 10% of sharks which had travelled over 1700 km to southern Australia. The proportion of sharks recaptured in their home Quota Management Areas (QMA) was 53% overall. However, the distance travelled increased significantly with time at liberty. After 2 years at liberty, only 22% of sharks were recaptured within a release QMA and 23% were recaptured in Australia. These findings suggest that future assessment of school shark fisheries within New Zealand waters should consider the species as one stock with a relatively high emigration rate to Australian waters.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516854

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A new species,Caelorinchus trachycarus, is described from continental slope depths of 622–1350 m off New Zealand, southern Australia, and the Norfolk Ridge south of New Caledonia. The modified scales of head ridges is especially spiny, more so than in any other member of the genus. The blackish fins, dark overall coloration, prominent free neuromasts on the head, and the numerous parallel rows of spinules on body scales distinguish the new species from the closely similar and sympatricC. acanthiger. It differs fromC. parallelusandC. kermadecusby its naked nasal fossa, snout length, and scale spinulation, among other characters.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516855

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Spawning, larval rearing, and growout ofRuditapes largillierti(Philippi 1849) were investigated in a series of trials conducted at the University of Tasmania (UTAS), Launceston and Georges Bay, St Helens, Tasmania, Australia. Intramuscular injection of serotonin (3 × 10‐7to 1.5 × 10‐6moles) failed to induce spawning in femaleRuditapes largillierti, although some males did spawn. Fecundity ofR. largilliertiinduced to spawn by thermal stimulus ranged from 0.5 to 0.9 × 106eggs female‐1. Fertilised eggs developed into trochophore larvae by 24 h at 20°C and D veligers with a mean shell length of 85.3 ± 4.7 μm within 48 h. Early larvae were frequently deformed and their mortality rates were very high. Development to pediveliger stage (mean shell length 200.3 ± 7.3 μm) took between 11 and 16 days at 20°C, and metamorphosis to spat (mean shell length 240 (μm) occurred between Days 16 and 19. There was no significant difference in efficacy of epinephrine, norepinephrine, or untreated groups for inducing larval settlement. Average growth of juveniles held subtidally within trays or baskets (mesh size 1.7–12.0 mm) was 1.3 mm month‐1. The aquaculture potential of this subtidal venerid clam warrants further investigation.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516856

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Photographic identification of individuals, a standard technique in the study of whales and dolphins, has seldom been attempted in pinniped studies. Photographs of damage and abnormalities in fore and hind flippers facilitated individual identification of almost 80% of individuals encountered during a 3‐year study of New Zealand sea lions(Phocarctos hookeri)at the Otago Peninsula. Lower canine size and large body scars were also useful in identifying individuals. None of the features used to identify the 48 individuals in this study changed sufficiently to hinder positive identification. Especially in small populations, the method has several advantages over traditional tagging.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516857

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Studies on New Zealand orange roughy(Hoplostethus atlanticus)otoliths, and of orange roughy ageing conducted in New Zealand and elsewhere are described. Ageing studies have concentrated on three aspects: the interpretation of daily growth increments, the interpretation of annual growth increments, and radiometric analyses. All the methods suffer from problems relating to validation. Daily growth zones have not been validated, annual zones have been validated for juvenile fish only, and assumptions necessary for the application of radio‐metric techniques may be flawed. However, the weight of current evidence indicates that orange roughy are a slow‐growing, long‐lived species. A review of otolith morphology and microstructure studies, and a summary of the productivity parameters used in stock assessments of orange roughy, are also presented. Standard protocols used to prepare and interpret otoliths in current investigations are described. This review highlights the complexities of ageing long‐lived, deepwater fish, and stresses the importance of obtaining accurate productivity parameters for stock assessment. The key area for future research is the age validation of post‐juvenile fish, which should lead to the development of an accurate ageing technique.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516858

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

To assess the impact of harvesting on woody debris volumes in streams, a method was required with sufficient precision to provide meaningful evaluation and comparison of pre‐ and post‐harvest levels of woody debris. Before harvest, woody debris volumes were measured in 24 first‐ to third‐order stream sites in New Zealand's mature pine plantations (22–34 years of age). An adaptation of the Van Wagner line intersect method was used to measure the small woody debris 1–9 cm in diameter (SWD). All large woody debris ≥10 cm in diameter (LWD) was measured for diameter and length. Woody debris volumes in the stream channel ranged from 2 to 345 m3ha‐1, averaging 112 m3ha‐1(±34, 95% confidence interval (CI)). Woody debris surface areas averaged 2883 m2ha‐1(±688), range 220–6769 m2ha‐1. Most of the woody debris volume (87%) was composed of LWD. Sixty‐seven percent of the woody debris volume was located above the stream, the remainder was lying in‐stream or on the floodplain. Woody debris volumes in streams of mature pine plantations in New Zealand were similar to woody debris volumes in streams of temperate native forests in New Zealand and North America. These sites will be remeasured after harvest to identify any changes in woody debris characteristics.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516859

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The tolerances of seven New Zealand freshwater fish species and one species of shrimp to low levels of dissolved oxygen were determined in the laboratory by holding fish at dissolved oxygen levels of 1, 3, or 5 mg litre‐1for 48 h at 15°C. Juvenile rainbow trout(Oncorhynchus mykiss)were also tested for comparison. All of the banded kokopu whitebait(Galaxias fasciatus), juvenile torrentfish(Cheimarrichthys fosteri), adult and juvenile common smelt(Retropinna retropinna), juvenile common bully(Gobiomorphus cotidianus), and trout were dead after 48 h exposure to 1 mg litre‐1. Adult and juvenile inanga (Galaxias maculatus), adult common bully(Gobiomorphus cotidianus), and shrimp(Paratya curvirostris)had mortalities ranging from 27 to 80% at 1 mg litre‐1, whereas all of the elvers (Anguillaspp.) survived. Juvenile rainbow trout were the most sensitive of the species tested, and the only species that had mortalities during exposure to 3 mg litre‐1. No deaths of any fish occurred at 5 mg litre‐1. Time to 50% mortality at 1 mg litre‐1for common smelt (adult and juvenile) and juvenile common bully were similar to those for juvenile rainbow trout. Most fish moved towards the surface within the first few hours of exposure to 1 mg litre‐1. Rainbow trout was the only species that showed consistent surfacing behaviour at 3 mg litre‐1and rarely were fish observed to move towards the surface at 5 mg litre‐l. Within the limits of the lifestages and species tested, adequate protection is provided for native fish by adopting the United States Environmental Protection Agency dissolved oxygen criteria for salmonid waters.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516860

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The movements of 74 rainbow trout(Oncorhynchus mykiss)were monitored every 2–3 days using radio‐telemetry during the spawning migration up the Tongariro River, New Zealand, between June and November 1995. Contrary to the views of anglers, movements of individual fish were highly variable and upstream movement could not be predicted from environmental conditions and fish related variables (length, sex, and reproductive status). There was no significant difference in individual movement between male and female fish. When individual movements were in an upstream direction, maiden trout moved faster, but less often, than fish that had spawned in previous years. The flow in the lower river explained 9% of the variance in individual downstream movements. Net upstream movement occurred throughout most of the study period with above mean activity when the river was in spate, especially early in the migration season when fish responded to flow changes as low as 7%. Above mean upstream daily movement occurred 8 times on rising and 9 times on falling barometric pressure. Large floods caused downstream displacements, but fish tended to move up stream again on the flow recession. The most noticeable downstream movement occurred following the eruption of Mount Ruapehu.

ISSN:0028-8330    

DOI:10.1080/00288330.1999.9516861

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor