Two new species of hatschekia (copepoda,dichelesthiidae) from New Zealand waters

Two new species of Hatschekia Poche, 1901 are described from New Zealand specimens of Allomycterus jaculiferus (Cuvier, 1818) and Lepidopus caudatus (Euthrasen, 1878) respectively. Comment is made on the need for revision within the genus Hatschekia.     

Echthrogaleus denticulatus smith (copepoda,pandaridae) in New Zealand waters

Dinematura neozealanica Thomson, 1889 is shown to be a synonym of Echthrogaleus denticulatus Smith, 1874. The male recorded as Pandarus armatus Heller by Thomson (1889) is probably E. denticulatus The latter species is redescribed from Thomson's specimens.     

Differences in the distributions of freshwater fishes and decapod crustaceans in urban and forested streams in Auckland,New Zealand

Using data from existing studies, assemblages of freshwater fishes and decapod crustaceans were examined at 39 sites in urbanised catchments and 57 sites in forested (reference) catchments within the greater Auckland region, New Zealand. Eleven native and 1 exotic fish species and 2 native decapod crustacean species were recorded. Species richness and fish Index of Biotic Integrity (IBI) scores were lower overall in streams in urbanised catchments. Shortfin eel (Anguilla australis) and mosquitofish (Gambusia affinis) were more dominant in urban streams; all other commonly occurring species were found significantly more often in reference streams. Non‐diadromous native species (Cran's bully (Gobiomorphus basalts) and freshwater crayfish (Paranephrops planifions)) were absent from urban streams, but relatively abundant in reference streams. This absence of non‐diadromous species, together with the urban occurrence of five diadromous species suggests that migratory barriers pose less of a threat to freshwater communities than physico‐chemical disturbance in streams in the Auckland urban region.     

Frigate tuna Auxis thazard in New Zealand waters (note)

Previous records of the frigate tuna Auxis thazard (Lacépède, 1802) were probably misidentifications of the slender tuna Allothunnus fallai. Frigate tuna were caught on the north‐east coast of New Zealand during 1975–76; the modal fork length of 176 specimens was 32–34 cm, and more detailed morpho‐metry and counts from 4 specimens are presented.     

Planktonic stages of the teleost family carapidae in eastern New Zealand waters

The occurrence of planktonic carapid eggs in Otago waters, of young stages of Echiodon rendahli off Castlepoint, and the possible presence of unrecorded members of the family Carapidae in New Zealand waters is discussed. Young E. rendahli possess a long spine which originates dorsally to a distinctive suspended gut.     

Precocious male quinnat salmon oncorhynchus tshawytscha (walbaum) in New Zealand (note)

Samples of yearling parr of quinnat salmon Oncorhynchus tshawytscha (Walbaum) from Lake Heron and the Glenariffe Stream were examined, and precocious ripe males were found. The proportion in the population (29.2%) was higher than is recorded in North America (2.6%).     

Reproduction in Galaxias fasciatus Gray (Salmoniformes : Galaxiidae)

A study of the reproductive cycle was made on Galaxias fasciatus Gray from streams on Banks Peninsula, South Island, New Zealand. There was no spawning migration; adults remained in the usual adult habitat to breed. The course of gonad maturation showed that spawning occurred in the autumn, from the end of April to mid‐June. Most males matured at 2 years of age and most females at 4 years old. Egg numbers in the females varied from 3800 to 23 600. Males were predominant in age groups 1–4, females in the older age groups. Amongst fish of potential breeding age there was an excess of males. Circumstantial evidence suggested that eggs were laid among piles of water‐logged debris lodged in pools and backwaters. The larvae, which are briefly described, probably hatch during floods to be swept quickly downstream to the sea.     

Nursery grounds of Tarakihi (Teleostei: Cheilodactylidae) around New Zealand

Nursery grounds of the tarakihi Cheilodactylus macropterus (Bloch & Schneider) were discovered in 1963–72 mainly off the south‐western coast of the North Island, in Tasman Bay, along the entire eastern coast of the South Island, and around the Chatham Islands. They occurred at depths of 20–100 m, and mostly between 10 km and 30 km from shore. The tarakihi nurseries had a dense and varied invertebrate bemthic epifauna dominated by sponges and small corals. Few signs of nurseries were found in. other New Zealand waters, in spite of the existence of major spawning grounds there. It is not known with which spawning grounds the various nursery grounds are linked.

The Tasman Bay nursery ground is 18–33 km wide and about 75 km long, with a surface area of about 2000 km². There is a rich demersal fish fauna (37 species were recorded) dominated by tarakihi, red gurnard Chelidonichthys kumu (Lesson & Garnot), snapper Chrysophrys auratus (Bloch & Schneider), and leathei'iacket Novodon convexirostris (Guenther). The young tarakihi occur at depths of 20–45 m and concentrate during winter in the warmer deeper water. They first appear in trawl catches in summer, towards the end of their first year (assumed birthdate is 1 March), and stay on the nursery until the age of 3 y. They occur in the deeper water off the nursery during their fourth and fifth year and depart during their sixth year, possibly for the spawning grounds off the west coast of the South Island. The mean lengths at the ages of 15, 27, and 39 months were 12.6, 18.0, and 24.0 cm respectively in 1970. There was some variation in growth rate within the nursery ground, but the age groups could nevertheless be recognised easily from, length frequency modes. Monthly modal lengths showed that growth slows down in winter. Evidence for fluctuations in year class strength was found; year classes 1966 and 1969 were weak and year class 1968 was strong.

The vulnerability of tarakihi less than 4y old to commercial New Zealand trawl gear is low, and the local fishing fleets do no serious damage to the habitat on the nursery grounds. However, a large part of the tarakihi nursery grounds off the east coast of the South Island lies outside the territorial fishing zone. Intensive fishing on these grounds by large foreign vessels using heavy trawl gear could have an adverse effect on the habitat of the young tarakihi in this region.     

Determination of total dissolved phosphorus in New Zealand fresh waters (note)

Ultraviolet digestion was found to be simpler and more convenient than perchloric acid digestion in the determination of total dissolved phosphorus in a variety of New Zealand freshwaters, but had limitations when used on waters with a high humic acid content.

Perchloric acid digestion was more powerful, breaking down polyphosphate bonds not affected by ultraviolet, but was subject to phosphorus losses from “bumping” during evaporation to dryness.     

Planktonic stages of Maurolicus muelleri (Teleostei Sternoptychidae) in New Zealand waters

The seasonality and distribution, abundance, and hydrological affinities of the planktonic stages of the sternoptychid Maurolicus muelleri (Grnelin, 1788) are described for the New Zealand region. Spawning occurred from August to March, and the planktonic stages were widespread around New Zealand. Spawning probably takes place around midday at depths greater than 250 m. Eggs and larval stages were present over temperature ranges of 9.0–15.5°c and 13–22°c respectively.     

Sodium fluoroacetate (1080) residues in longfin eels,Anguilla dieffenbachii,following exposure to contaminated water and food

Captive longfin eels (Anguilla dieffenbachii) were exposed to the vertebrate pesticide sodium fluoroacetate (1080) in the water column and through the ingestion of cereal pellet baits or possum muscle and gut tissue that contained 1080 residue. No mortality or unusual behaviour (in comparison with the controls) occurred in eels that were exposed to 1080. However, significantly greater weight loss occurred in eels exposed to 1080 compared with those eels that were not. No residue was detected in tissues of eels exposed to 1080 cereal baits through ingestion and direct (dermal and respiratory) absorption, or through direct absorption only. Low concentrations of 1080 were detected in muscle tissue of eels that consumed contaminated possum muscle (x = 0.0174 μg/g) or gut (x = 0.0306 μg/g) tissue. The primary factors affecting the concentration of 1080 detected in eel tissue included the dose of 1080 (mg/kg) that each eel" receiveddate="and number of days since the eel last fed on contaminated tissue. Based on the 1080 concentrations measured in eels in this study, the risk of acute poisoning to humans from eating contaminated eel flesh is considered extremely low. Even so, national and international perceptions and food safety standards have the potential to limit eel exports and/or close an eel fishery if 1080 residue was discovered in tissue.     

Helminth parasites of brown trout (Salmo Trutta L.) in Canterbury,New Zealand

Neopeltopsis pectinipes gen. et sp. nov. is described and figured from sublittoral marine algae at Wellington, New Zealand; the genus is an addition to the Peltidiidae Sars. The genus is compared with the other genera of the family, and a revised key is given to the genera of the Peltidiidae.     

Distribution,seasonality, lengths,and feeding behaviour of whale sharks (Rhincodon typus) observed in New Zealand waters

Data from 36 whale shark (Rhincodon typus Smith, 1828) sightings off north‐east North Island, New Zealand are summarised. Sightings were concentrated over the outer shelf and shelf break in areas influenced by the East Auckland Current at sea surface temperatures (SST) of 21–24°C. Sightings occurred from late spring to early autumn (November‐April) but were most frequent in midsummer (February) when upwelling along the north‐east shelf is weakest. The data indicate whale sharks occur off north‐east New Zealand most summers, including those when SST is colder than usual. A cluster of sightings and three observations of whale sharks feeding on schools of anchovy (Engraulis australis) near Whale Island, Bay of Plenty, suggest whale sharks may aggregate seasonally in this area. Estimated total lengths (TL) of 26 whale sharks ranged from 3.5 to 15 m, with 73% between 6 and 9 m TL.     

Validated aging methodology using otoliths,and growth parameters for hoki (Macruronus novaezelandiae) in New Zealand waters

The age of hoki was determined by counting bands in otolith cross‐sections. The technique was validated using the progression of length modes in length‐frequency distributions (for age classes 0+ to 4+) and the progression of strong and weak year classes in age‐frequency distributions from commercial catches sampled off the west coast of the South Island, New Zealand, from 1988 to 1994. Von Bertalanffy growth parameters for the west coast and Cook Strait spawning populations are significantly different, providing further support for a two‐stock hypothesis. In both areas female hoki have a growth rate significantly faster than males, and also a greater life expectancy.     

Evidence of summer parturition in shortfin mako (Isurus oxyrinchus) sharks from New Zealand waters

A litter of eight near‐term shortfin mako (Isurus oxyrinchus Rafinesque 1810) embryos is described from a 317.5 cm total length (TL) female caught off Hawke Bay, south‐east North Island, New Zealand on 5 February 1999. The embryos (3 males and 5 females) were 67.2–77.0 cm TL. Embryo length, condition, hepato‐somatic indices, and mass of yolk in their stomachs all indicate they were close to birth. This is the first shortfin mako litter reported from New Zealand and is outside the late winter‐early spring parturition period predicted from estimated embryonic and juvenile growth rates. Uterine width data from four mature non‐pregnant females and age‐0+ length‐at‐capture data suggest parturition occurs from September to late February (late winter‐mid summer) but is infrequent after January. We suggest that shortfin makos have an extended parturition period, possibly year‐round, with peak parturition occurring in late winter‐spring.     

Spawning of the frostfish,Lepidopus caudatus (Pisces: Trichiuridae), in New Zealand waters

Frostfish spawning, as indicated by the presence of planktonic eggs, was observed mainly in north‐eastern, but also in south‐western, New Zealand waters in spring to autumn. Spawning takes place in the afternoon in outer shelf waters 50–200 m deep, with surface temperatures and salinities between 17.5 and 22.0°C and 35.3 and 35.6‰ respectively. Egg and oil droplet diameters ranged from 1.65 to 1.75 mm and 0.40 to 0.43 mm respectively.     

The two species of sprat in New Zealand waters (Sprattus antipodum and S. muelleri)

Two broadly sympatric species of sprat are shown to inhabit New Zealand waters, the more slender Sprattus antipodum (Hector, 1872) and the more common and deeper‐bodied S. muelleri (Klunzinger, 1872). Overlap in most morphometric and meristic characters had earlier led to their synonymy, but recent protein analysis suggested otherwise. This is now confirmed by distinct differences in shape and dentition of the basihyal plate, vertebral numbers, scale sculpture, and fresh colour. The five known species of Sprattus are keyed and the genus diagnosed and discussed.     

Diadromy and longitudinal patterns of upstream penetration of freshwater fish in Taranaki,New Zealand

Diadromous fish species dominate the New Zealand freshwater fish fauna and make up 15 of the 17 native fish species found on the Taranaki Ring Plain. Trajectories of occurrence in relation to elevation and distance from the sea are described for 11 diadromous and 2 non‐diadromous species using data from the New Zealand Freshwater Fish Database and data collected over the summer of 1997/ 98. Distinctive distributions were found for most of the species related to their differing migratory strategies and abilities. The species were ranked based on components of these trajectories to compare their penetrative ability. Comparison of the ranking methods used revealed they produced similar results. The ranking of the 11 diadromous species in Taranaki relative to each other revealed similar rankings to those for the same species from the West Coast of the South Island. The non‐migratory native fish, Cran's bully (Gobiomorphus basalis), was not found on the western side of the mountain. This distribution is thought to be the result of the local extinction of non‐migratory species in high gradient or unstable streams.     

From Vagrant to Resident: occurrence,residency and births of leopard seals (Hydrurga leptonyx) in New Zealand waters

ABSTRACT

In contrast to previous reports that leopard seals (Hydrurga leptonyx) are rare vagrants to New Zealand, we show that this species is a regular member of the marine fauna of this region. We present a first analysis from the New Zealand Leopard Seal Database – an extensive collation of 2,711 records of leopard seals within New Zealand between 1200 and 2018. Of these records, 51.2% (n?=?1,408) were photographic. Leopard seal sightings have increased over time and been reported in all seasons and regions of New Zealand. Sightings are predominantly of adult individuals of good or excellent body condition, which differs to previous hypotheses suggesting that leopard seals visiting New Zealand shores are primarily juvenile animals in poor health condition. A total of 176 unique individuals have been identified in the New Zealand Leopard Seal Catalogue between 2014 and 2018 and preliminary results indicate that numbers per annum have continued to increase over time. Three leopard seal births and a number of juvenile animals (34% of the NZ records) have been documented. Considering the information presented here and the current definitions in the New Zealand Threat Classification System, the threat status of leopard seals within New Zealand waters should be reclassified from Vagrant to Resident.     

Propeller scars on and known home range of two orca (Orcinus orca) in New Zealand waters

Two orca (Orcinus orca, Linnaeus, 1758), photo‐identified as part of an ongoing study in New Zealand waters, have a series of deep scars in their dorsal lumbar‐caudal regions which suggests they were caused by propellers. One of the animals, first noted to have the scars in 1982, is considerably smaller than an adult of similar age. The known home range of these orca are presented. A third orca hit by a boat is presumed dead.