Tasman Bay Research Articles

Coral‐like bryozoan growths in Tasman Bay, and their protection to conserve commercial fish stocks

Abstract 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.

The mucilage‐producingPhaeocystis pouchetii(Prymnesiophyceae), cultured from the 1981 “Tasman Bay slime”

Abstract The mucilage‐producing colonial form of Phaeocystis 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‐producing Phaeocystis colonies in association with other phytoplankton is suggested to be the cause of the “Tasman Bay slime” outburst in spring 1981.

Evidence for two species of arrow squid in the New Zealand fishery

Abstract Electrophoresis, comparative morphology, and prevalence of parasites were examined in arrow squid Nototodarus sloani from New Zealand waters. Electrophoresis revealed 2 alleles at the a‐glycerophosphate dehydrogenase locus. Specimens from eastern and southern areas of New Zealand were fixed for a slow allele and specimens from western areas were fixed for a fast allele. Two types of hectocotylised ventral arms were observed in mature males; one type was found in eastern and southern areas and die other in western areas. Nybelinia sp. post‐larvae showed high infestation levels in western squid, but none were found in eastern and southern specimens. It is concluded that there are 2 species of arrow squid in New Zealand and that these are associated with the major water masses. Some overlap between the species was found in fishery areas Cook Strait, Tasman Bay, and Egmont.

Resonant over-tide across and along Tasman Bay, New Zealand

East-west current oscillations in Tasman Bay with a quarter (6.2 h), sixth (4.1 h) and eighth (3 h) diurnal periodicity are shown to be generated by non-linear field acceleration of the semi-diurnal tidal water motion near D'Urville Island resulting from rapid change of the tidal amplitude with distance. These over-tides force oscillations directed across (quarter and eighth-diurnal) and along (sixth-diurnal) Tasman Bay in which respective directions the quarter wavelength oscillation wave resonant periods are near the quarter and sixth diurnal period.

Resonant over-tide across and along Tasman Bay, New Zealand : Heath, R. A., 1979. Estuar. coast. mar. Sci., 8(6): 583–595

Resonant over-tide across and along Tasman Bay, New Zealand : Heath, R. A., 1979. Estuar. coast. mar. Sci., 8(6): 583–595

Surface waters of Waimea Inlet and Nelson Ha Yen: A preliminary assessment of quality

Abstract Because of mounting inflows of sewage and organic industrial effluents in Nelson Haven, Waimea Inlet, and Tasman Bay, a water quality survey to obtain background information, on 17 parameters from 28 sites was made during 1975. Some water samples collected near effluent discharges showed high levels of nitrate, total nitrogen, total phosphorus, volatile solids, ATP, heterotrophic potential, total bacteria, viable bacteria, and coliform bacteria. Measurements were also made of temperature, salinity, dissolved oxygen, pH, suspended solids, and chlorophyll a; counts were made for confirmed faecal coliforms and confirmed Escherichia coli (Type I). Water from sites remote from effluent discharges showed characteristics of normal seawater: water turbulence and tidal flushing appeared to be rapidly degrading, diluting, and dispersing the organic contaminants.

Currents and hydrology in Tasman and golden bays, South Island, New Zealand

Abstract 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. Warmer water was found to be associated with shallower depths, and diurnal temperature changes were observed. The currents in the bay were mainly tidal, the residual currents being very small.

Circulation in Tasman Bay

Abstract Direct current measurements at four locations in Tasman Bay and numerical model results are used to analyse the mean flow in Tasman Bay. The mean circulation conforms to that previously found from drift card experiments: a clockwise circulation in Golden Bay, and an anti‐clockwise flow in Tasman Bay, with a return south‐westerly flow on the coast near Nelson. Typical mean speeds are 0.02–0.05 m.s‐1. The circular flow appears asymmetrical in both bays, with a stronger outflow along Farewell Spit in Golden Bay and near D'Urville Island in Tasman Bay. An analytical tidal solution is used to exhibit the influence of Cook Strait in producing smaller tidal amplitudes in eastern Tasman Bay. Tidal speeds of 0.15–0.30 nus‐1 are typical, with tidal ellipses having degenerated into north‐east, south‐west lines.

Parasites in tarakihi (pisces: Cheilodactylidae) from three areas around New Zealand

Abstract The parasite faunas of tarakihi Cheilodactylus macropterus (Bloch & Schneider) from East Cape, Tasman Bay, and the Chatham Islands were compared. A total of seven parasite species were found of which four were recorded in tarakihi for the first time: Nybelinea sp., Hepatoxylon trichiuri (Holten), Echinorhynchus sp. and Clavellodes sp. The last two of these were new records for New Zealand. The other parasites were: Contracaecum sp., Anisakis sp. and Aethon garricki Hewitt. The nematode Anisakis sp. and the copepods Aethon garricki Hewitt and Clavellodes sp. were the commonest parasites. Incidence and intensity of Anisakis sp. were high off the Chatham Islands, moderate off East Cape, and low in Tasman Bay. These differences in infestation were truly regional and were only partially caused by differences in age composition of the fish samples. Intensity of infestation with Anisakis sp. was related to age of fish off the Chatham Islands, but not in the other two areas, and this probably reflects regional differences in the diet of the tarakihi. Incidence of Clavellodes sp. was low in Tasman Bay. This parasite was absent from the other two areas, which either may indicate a true regional difference in the distribution of the parasite or may be caused by differences in the age composition of the samples. Incidence of Aethon garricki was moderate in Tasman Bay and off East Cape, but this parasite did not occur in the Chatham Islands tarakihi. Thus, tarakihi populations from three widely separated areas differed from each other in the incidence and intensity of at least one of the three commonest parasites.

Broad classification of New Zealand inlets with emphasis on residence times

Abstract Thirty‐two New Zealand coastal inlets are tentatively classified into seven groups with probable similar circulation patterns, based on ratios of their physical parameters: volume, tidal compartment, entrance width, surface area, length, and average width. Eighteen of these have a predominant tidal flow, shown from their small ratio (ß < 4) of tidal compartment to total volume, and the cross‐sectional areas of their entrances are controlled by the tidal flow: Moutere, Waimea, Aotea, Whanganui, Avon‐Heathcote, Tauranga, Parengarenga, Porirua‐Pauatahanui, Kawhia, Nelson, Rangaunu, Raglan, Whangarei, Bluff, Otago, Hokianga, Manukau, and Whangaruru. The other fourteen range from long narrow sounds with probable strong vertical circulation (e.g., Pelorus Sound) to large bays with strong mean horizontal circulations (e.g., Tasman and Hawke Bays). Examples of residence time calculated in inlets with ß > 4 are given for Tasman Bay, a bay with a mean horizontal circulation, which has a residence time of 1–3 months, and Pelorus Sound, an inlet with a vertically complex circulation, which has a residence time of about 20 d.

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

Abstract 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.

The lunar semi-diurnal tide in Cook Strait, New Zealand

The lunar semi-diurnal tide in Cook Strait responds to two tidal systems one on each end of the Strait, these systems being about 140° out of phase. The tide in Cook Strait and that in the adjacent Tasman Bay are examined by numerical integration of the momentum and continuity equations with tidal forcing from both the open boundaries. This model simulates the tide very closely. The region of rapid phase change in the narrowest part of Cook Strait is found to be consistent with two overlapping standing waves. Elsewhere the tidal wave has a dominant standing wave component.

Observations on the biology of Apatopygus recens (Echinoidea: Cassiduloida) around New Zealand

The biology of the New Zealand cassiduloid echinoid Apatopygus recens is reviewed in terms of its geographical distribution, sediment relationships, and associations with other echinoids. Observations were also made on the density and size‐frequency distribution of an A. recens population at Croisilles* Harbour, Tasman Bay, and on the burrowing and feeding behaviour of specimens from this locality in an aquarium. A. recens is a rapid and continuous deposit feeder which burrows completely beneath the surface of the coarse sediments with which it is characteristically associated. The construction of a respiratory burrow to the sediment surface was not observed and the species appears to rely entirely on an adequate interstitial water flow for its respiratory requirements. Two 24 mm long specimens each defaecated an average of 0·76 g dry wt of sediment/h which at the Croisilles Harbour habitat was equivalent to a population ingestion rate of about 7·6 g dry wt of sediment/m2/h.

Population study ofPectinaria australis(polychaeta) in Tasman Bay

Abstract Grab samples were taken from a population of Pectinaria australis Ehlers in Tasman Bay, New Zealand, at intervals over a 2‐year period, March 1971 to March 1973. Settlement occurred in summer with the new recruits showing rapid growth and heavy mortality, giving an apparent life cycle time of 1 y. The population density varied greatly over short distances at one time, presumably due to random settlement of aggregations of larvae from the plankton.

Food of Tarakihi in Western bay of plenty and Tasman bay, New Zealand

Abstract Feeding was examined in 1574 tarakihi, Cheilodactylus macropterus (Bloch and Schneider) (Teleostei: Cheilodactylidae). Occurrence, points (bulk), and numbers methods of gut content analysis were used throughout the study. By all three methods of analysis, polychaetes, crustaceans, echinoderms, and molluscs (in that order) generally formed the main food groups. Crustaceans dominated the food of tarakihi <15cm in fork length, and polychaetes were the dominant food group in specimens ≥ 15 cm. Length of specimen, sampling depth and area, geographical region, and time of day affected the occurrence, volume, and numbers of food items in the gut, but sex and season did not. Male tarakiili frequented deeper water than females; this result was significant at the <0.001 level.

Dolphin sightings, Tasman bay to Cook Strait, New Zealand, September 1968‐June 1969 (note)

Abstract Seventy‐one schools of dolphins were sighted, in which four species were identified: common dolphin, Delphinus delphis Linn.; dusky dolphin, Lagenorhyn‐rhus obscurus (Gray); bottlenose dolphin, Tursiops truncatus (Montagu); and Hector's dolphin, Cephalorhynchus hectori (van Beneden). Of the 71 schools, 37 were of common dolphin, 12 of dusky, 12 of bottlenose, and 5 of Hector's; and 5 were mixed (4 schools of common + dusky; and 1 of these two + bottlenose). Sightings of albino specimens of common and bottlenose dolphin are recorded, and copulation is described for these species. Scarcity of summer sightings of common and dusky dolphin is related to observations of large, apparently migratory schools elsewhere in New Zealand waters during this season. Observations on all four species revealed a mean sustained swimming speed of around 15–18 km.h‐1, and a maximum of 36km.h‐1. Common dolphin were observed to spout for air at 6–10 s intervals, with occasional longer dives of 15–20 s. Sea surface temperatures in the range 9.5–20.0°c are plotted as seasonal ranges in the Tasman Bay, Marlborough Sounds, and Cook Strait areas respectively, and are related to the presence or apparent absence of each species.

Meteorological effects on the surface circulation and hydrology of Tasman bay, New Zealand

Abstract Analyses of trajectories of drift cards, released over a 2‐year period April 1969‐Aprit 1971, and hydrological observations at nine stations all occupied in and near Tasman Bay within 19 hours on 4–5 March 1970, show variable surface flows, which are strongly influenced by wind. Water characteristics are altered by insolation and coastal run‐off. The exchange times for the water in Tasman Bay were calculated for differing wind speeds.

Broadbilled swordfish from Tasman bay, New Zealand (note)

Abstract On 4 January 1971 a solitary specimen of the broadbilled swordfish Xiphias gladius Linneaus (Osteichthyes: Xiphiidae) was shot in Croisilles Harbour (41° 04’ S, 173° 40’ E). This was the first time the species has been recorded in the Tasman Bay area.

Gravity, seismicity, and tectonics of the North Island, New Zealand

Abstract The distribution of earthquakes and gravity anomalies in New Zealand are compared. Shocks classified as 12 km or less are more widespread than those classified as 33 km, but all crustal shocks are symmetrically disposed about the axis of the negative isostatic gravity anomalies. A minimum of seismicity occurs between the base of the crust and about 80 km depth which conflicts with the author's previous suggestion that low densities between these depths are associated with seismicity. The Benioff zone dips at 63° and high densities associated with this zone would be consistent with the positive gravity anomaly. In plan, the main belt of shallow earthquakes follows the negative gravity anomaly axis in changing direction from SW to SSE through Cook Strait. A relatively aseismic region in the upper crust following a parallel strike from south Taranaki through Tasman Bay to Kaikoura separates the main zone from a further active belt running from New Plymouth through north-west Nelson to Canterbury. All these directions cross the main geological structures almost at right angles in the Cook Strait-Marlborough area. There is some evidence that the deeper earthquakes tend to change their strike in a similar manner

PETROLEUM PROSPECTS OF TASMAN AND GOLDEN BAY AREAS, SOUTHERN COOK STRAIT, NEW ZEALAND

Petroliferous sediments of Lower Tertiary age are preserved in a number of sub-basins, basin synclines and graben along the western portions of both islands of New Zealand.These form part of the extensively disrupted lineal and platform-like Cretaceous-Tertiary "West Basin" or geosyncline which is separated from a comparable "East Geosyncline" by the geanticlinal backbone of the New Zealand island-chain.Sedimentation in the West Basin was thick (10,000 to 20,000 feet or more) and continuous throughout much of the Cretaceo- Tertiary interval. Unconformities, where present, tend to be local features, but may still represent marked erosional and/or structural breaks. Lithologic and facies changes are not infrequent on a small scale, but these are superimposed on regional sequences that are traceable over the full longitudinal extent of the overall basin.Cretaceous to Lower Tertiary sequences tend to be freshwater and coal-bearing, but may be "paralic" locally. More marine facies are predicted beneath Cook Strait. Later Tertiary sediments are more predominantly marine, and include big thicknesses of mudstone and limestone.Oil seepages occur in a number of situations in the West Basin, and are associated with Lower Tertiary coal measures. In the Taranaki sub-basin the small oil field at New Plymouth has produced a total of 200,000 barrels of oil and 65 million cubic feet of gas, while the more recently discovered (1959) Kapuni condensate-gas field is capable of producing 60 million cubic feet of gas per day, of which 40 per cent is CO, accompanied initially by 4,500 million barrels per day of condensate.The Nelson and Farewell Spit sub-basins of present interest respectively plunge north beneath Tasman and Golden Bays on either side of the Pikikirunl Range "horst". They then coalesce beyond Separation Point and link with the Kapuni sub-basin beneath Cook Strait as part of the modern continental shelf. These graben-like developments are characterised by strong north plunge.Geophysical surveys leading to the better understanding of basin sub-structure about southern Cook Strait are discussed, followed by consideration of possible petroleum potential. Gravity anomalies in both the Tasman and Golden Bay areas, supported by seismic surveys, have confirmed anticlinal structure. Structural and stratigraphic traps for petroleum are predicted in relation particularly to these developments.