Cooperative breeding, widely reported in birds, is found in <1–5% of territories in some populations of the Brown skua, Catharacta lonnbergi. In the New Zealand region, up to 30-50% of skua territories may be occupied by trios or larger groups. This study examines its occurrence at the Chatham Islands, east of New Zealand. Here 16% of territories are occupied by trios and 2% by groups. All members of skua trios and groups participate in sexual and other breeding activity, and the associations arc thus communal. Sexual discrimination of breeding birds by morphometric measurements shows that all communal groups known since 1978-79 have been polyandrous. These groups are long-lived associations, some of which are known to have persisted for at least 14 years. Trios are as long-lived and stable as pairs, and birds on communal territories do not move from them even when an appropriate-sex space becomes available on an adjacent pair territory. The members of trios are not close kin. All members of communal associations participate in territorial defence and chick rearing. In trios, the males appear to be equals, although in any one year the actual paternity of offspring may reside with only one of them. Overall reproductive success for Chatham Island skuas is high, for both pairs and communal groups, compared with other populations. However, communal trios and groups have lower reproductive success than pairs even over a l0 year period, particularly when considered on a per adult basis. Furthermore, no improvement in chick ‘quality’ is discernible. Unusually for skuas, the breeding population at the Chatham Islands is non-migratory. Skuas are present on their breeding territories during the winter, and exhibit characteristic territorial and agonistic behaviours, albeit at lower intensity than during the breeding season. It is suggested that communal breeding in this skua population is not adaptive per se, but a secondary consequence of year-round residence. This is a departure from the conventional resolution of communal breeding. Residence is facilitated by benign climatic conditions and year-round prey availability. When territory space becomes available outside the breeding season, in a small number of cases more than a pair of skuas are able to establish themselves. Thereafter, trios and larger groups persist and behave in the same manner as pairs. The flux between trios and pairs when birds are lost is determined, in part, by the sex of that bird. Thus a trio which loses its one female will ‘acquire’ a replacement female and persist as a trio, whereas a trio which loses one of its two males will thereafter continue as a pair. Keywords: Cooperative breeding, communal breeding, polyandry, Stercorariidae, skuas, skua trios, skua behaviour, skua breeding, Chatham Islands / Chapter 1 previously published as: Cooperative breeding in the Skuas (Stercorariidae): History, distribution and incidence. Journal of the Royal Society of New Zealand 24: 245-260 (1994). Publisher version available at http://www.royalsociety.org.nz/Site/publish/Journals/jrsnz/1994/default.aspx / Chapter 2 previously published as: Winter territory occupation and behaviour of Skuas at the Chatham Islands, New Zealand. Emu 90: 108-113 (1990). Publisher version available at http://www.publish.csiro.au/nid/96.htm / Chapter 3 previously published as: Communually breeding Skuas: Breeding success of pairs, trios and groups of Catharacta lonnbergi on the Chatham Islands, New Zealand. Journal of Zoology, London 218: 393-405 (1989). The definitive version is available at www.blackwell-synergy.com

The population dynamics of juvenile snapper, Pagrus auratus, were investigated in the Hauraki Gulf, north-eastern New Zealand, between 1982 and 1990. Attention focused on age and growth, temporal and spatial variation in abundance, and recruitment. Daily increment formation was validated in the sagittae of snapper up to about 160 days old. Increment width varied with time of year, and snapper age, and increments were not resolvable with a light microscope during winter. Increment counts inside a prominent metamorphic mark showed that larval duration was 18-32 days, and was inversely related to water temperature. Spawning dates were back-calculated from increment counts in settled juveniles, and ranged from September to March with a peak in November-January. The onset of spawning was temperature dependent. Fast-growing snapper had smaller sagittae than slow-growing snapper, indicating an uncoupling of otolith and somatic growth. Snapper gonads differentiated first as ovaries during the second year of life, and then some juveniles changed sex to become males during their third year. Sex change occurred before maturity, so snapper are functionally gonochoristic. Growth was slow during the larval phase, but increased rapidly after metamorphosis to about 0.6-0.9 mm.day-1. From the first winter, growth followed a well-defined annual cycle, with little or no growth during winter, and linear growth of 0.16-0.43 mm.day-1 during spring-autumn for 0+/1+ and 1+/2+ snapper. Snapper grew faster at higher temperatures. Trawl catch rates were affected by numerous gear and environmental factors, but probably provided reasonable estimates of snapper relative abundance. Recommendations are made for improving snapper trawl survey procedures. There was a strong annual abundance cycle in the Kawau region, peaking in spring, and declining to a minimum in winter. Snapper were patchily distributed at a spatial scale of 1-2 km, probably because of preference for specific micro-habitats. Year class strength of 1+ snapper varied 17-fold over seven years, and was strongly positively correlated with autumn sea surface temperature during the 0+ year. The strengths of the 1991 and 1992 year classes are predicted to be below average, and extremely weak, respectively.

This thesis develops a quantitative cladistic approach to panbiogeography. Algorithms for constructing and comparing area cladograms are developed and implemented in a computer program. Examples of the use of this software are described. The principle results of this thesis are: (1) The description of algorithms for implementing Nelson and Platnick's (1981) methods for constructing area cladograms. These algorithms have been incorporated into a computer program. (2) Zandee and Roos' (1987) methods based on "component-compatibility" are shown to be flawed. (3) Recent criticisms of Nelson and Platnick's methods by E. O. Wiley are rebutted. (4) A quantitative reanalysis of Hafner and Nadler's (1988) allozyme data for gophers and their parasitic lice illustrates the utility of information on timing of speciation events in interpreting apparent incongruence between host and parasite cladograms. In addition the thesis contains a survey of some current themes in biogeography, a reply to criticisms of my earlier work on track analysis, and an application of bootstrap and consensus methods to place confidence limits on estimates of cladograms.

Growth, development and behaviour were examined in artificially reared larval Pagrus auratus and Forsterygion varium, from the time of hatching. Yolk-sac larval P.auratus hatched at a small size (2.00mm SL), without functional eyes, mouth or digestive tract, and for three days spent long periods at rest. Growth was initially rapid but slowed by 3 days as yolk reserves neared depletion. By days 4-5, the mouth had opened, eyes were functional, yolk was depleted, and a rudimentary gut had formed. Larvae were now able to maintain a horizontal swimming mode and were actively searching for and attacking prey. First feeding was observed in some larvae. Growth was retarded during the transition from endogenous to exogenous nutrition and then increased as feeding proficiency improved. Yolk-sac F.varium hatched at a larger size (4.78mm SL), with functional eyes and jaws. Larvae were able to maintain a horizontal swimming mode from hatching. First feeding was observed from the first day after hatching. F.varium larvae grew steadily from the time of hatching. Ocular morphology was examined in larval, juvenile and adult P.auratus and F.varium. There was a 96 fold increase in eye size, from 0.23mm diameter in a 4 day old larval P.auratus (3.4mm SL) to a maximum diameter of 22mm in an adult of 333mm body length. F.varium displayed a 26 fold increase in eye size, from 0.28mm diameter in the smallest larva (5.00mm SL) to a maximum eye diameter of 7.2mm in a 11gmm long adult. Larval fish had pure cone retinae, however putative rod precursor cells were present from hatching in F.varium and from 18 days in P.auratus. Juvenile and adult fish had duplex retinae with cones arranged in a square mosaic in which 4 twin cones surround a central single cone. Hypertrophy of cone ellipsoids with increasing eye size, resulted in maintenance of a closely packed array in fishes of all sizes. The appearance of retinomotor movements was coincident with the development of a duplex retina in both species. Theoretical spatial acuity (calculated as a function of cone spacing and focal length of the lens) was poor in the smallest larval fish (2° 1' and 1° 8' minimum separable angle in 4 and 1 day old P.auratus and F.varium respectively) but improved to asymptotic values in adults (3'- 4', and 9' in P.auratus and F.varium respectively). Behavioural acuity (determined using the optokinetic response) of 4 day old larval P.auratus (37° 30') and 1 day old F.varium (29°) was very much lower than histological estimates. Behavioural acuity improved to 8° 8' in 16 day old P.auratus and 4° 18' in 14 day old F.varium, but did not attain theoretical estimates for fish of that size (55' and 54'). A rudimentary retractor lentis muscle was first apparent in larval fish 1 week after hatching, and was coincident with the formation of a posterior lental space. Presumably larval fish eyes were incapable of accomodative lens movements until this time. A relative measure of Matthiessen's ratio (distance from lens centre to boundary of the pigmented retinal epithelium/lens radius) measured histologically, decreased from 4.2 and 2.7 in 3 day old P.auratus and newly hatched F.varium, to 2.2 and 2.3 in larvae 22 and 16 days of age respectively. This suggests that growth of the retina and lens were not symmetrical in the eyes of very small larval fish. If Matthiessen's ratio holds for little eyes, then they will initially be strongly myopic. This may account in part for the mismatch between behavioural and theoretical acuity. Perceptive distances of first feeding larval P.auratus and F.varium, estimated for prey items equal in dimensions to maximum jaw widths, were very small (0.2mm and 0.4mm for prey 0.15mm and 0.2mm in size respectively), but increased with increasing body size to 2.1mm and 4.0mm for prey 0.3mm in size, at 16 and 14 days of age respectively. These data have implications for larval feeding in the wild.

Introduction. In the past thirty years studies of community and population ecology of marine soft-shore invertebrates have increased, both in number and in depth, A good knowledge is building up of the interactions of benthic invertebrates with their physical and biotic environments. (Boughey, 1967; Green, 1968; Nancock and Simpson, 1962;) This thesis examines the ecology, population dynamics, and energetics of some common intertidals soft-shore molluscs, having particular concern with the range of variation that is possible in one parameter for different populations of the same species. Similar work has not been frequently attempted for molluscs, although there is some information available from syntheses of the work of different authors on the same species.(Bullock, 1955; Dehnel, 1955; Fretter and Graham, 1962; Hyman, 1967 ; Prosser , 1955; Wilbur and Yonge, 1966;) Most authors have concentrated either on the ecology of a species, or on the population dynamics of one population, or perhaps on the influence of one environmental factor, such as temperature, on one parameter, such as growth rate; rarely has there been a study of the interaction of several environmental factors with several population parameters . (Wilbur and Owen, 1964;)

The Ecology of the entrance to the Whangateau Harbour Northland New Zealand 1. General Introduction 1.1 Aims of this work. The broad object of this work has been to improve understanding of shallow water marine environments and their faunal associations. To this end, information has been integrated from a number of specific investigations which were: 1. To examine the benthic macrofauna associated with sedimentary deposits, in an area with steep environmental gradients and associated complexity of faunal distributions. 2. To identify and describe the major benthic marofaunal associations, using both classical “intuitive" methods and more objective statistical methods employing computer techniques. 3. To investigate the hydrological and sedimentary features of the local environment, as a background to the faunal investigations. 4. To relate the distribution of the fauna and associations ;a selected environmental parameters, with particular reference to the grain-size characteristics of the sediments. 5. To relate the faunal associations to similar associations elsewhere in New Zealand and overseas. 6. To investigate the relationships between the living fauna and the dead remains of organisms found in the sediments, with the view to providing information which may be usefull to paleaecologists. 7. To try to portray certain aspects of the underwater environment difficult to appreciate by means other than diving.

The population dynamics of juvenile snapper, Pagrus auratus, were investigated in the Hauraki Gulf, north-eastern New Zealand, between 1982 and 1990. Attention focused on age and growth, temporal and spatial variation in abundance, and recruitment. Daily increment formation was validated in the sagittae of snapper up to about 160 days old. Increment width varied with time of year, and snapper age, and increments were not resolvable with a light microscope during winter. Increment counts inside a prominent metamorphic mark showed that larval duration was 18-32 days, and was inversely related to water temperature. Spawning dates were back-calculated from increment counts in settled juveniles, and ranged from September to March with a peak in November-January. The onset of spawning was temperature dependent. Fast-growing snapper had smaller sagittae than slow-growing snapper, indicating an uncoupling of otolith and somatic growth. Snapper gonads differentiated first as ovaries during the second year of life, and then some juveniles changed sex to become males during their third year. Sex change occurred before maturity, so snapper are functionally gonochoristic. Growth was slow during the larval phase, but increased rapidly after metamorphosis to about 0.6-0.9 mm.day-1. From the first winter, growth followed a well-defined annual cycle, with little or no growth during winter, and linear growth of 0.16-0.43 mm.day-1 during spring-autumn for 0+/1+ and 1+/2+ snapper. Snapper grew faster at higher temperatures. Trawl catch rates were affected by numerous gear and environmental factors, but probably provided reasonable estimates of snapper relative abundance. Recommendations are made for improving snapper trawl survey procedures. There was a strong annual abundance cycle in the Kawau region, peaking in spring, and declining to a minimum in winter. Snapper were patchily distributed at a spatial scale of 1-2 km, probably because of preference for specific micro-habitats. Year class strength of 1+ snapper varied 17-fold over seven years, and was strongly positively correlated with autumn sea surface temperature during the 0+ year. The strengths of the 1991 and 1992 year classes are predicted to be below average, and extremely weak, respectively.

This thesis develops a quantitative cladistic approach to panbiogeography. Algorithms for constructing and comparing area cladograms are developed and implemented in a computer program. Examples of the use of this software are described. The principle results of this thesis are: (1) The description of algorithms for implementing Nelson and Platnick's (1981) methods for constructing area cladograms. These algorithms have been incorporated into a computer program. (2) Zandee and Roos' (1987) methods based on "component-compatibility" are shown to be flawed. (3) Recent criticisms of Nelson and Platnick's methods by E. O. Wiley are rebutted. (4) A quantitative reanalysis of Hafner and Nadler's (1988) allozyme data for gophers and their parasitic lice illustrates the utility of information on timing of speciation events in interpreting apparent incongruence between host and parasite cladograms. In addition the thesis contains a survey of some current themes in biogeography, a reply to criticisms of my earlier work on track analysis, and an application of bootstrap and consensus methods to place confidence limits on estimates of cladograms.

Growth, development and behaviour were examined in artificially reared larval Pagrus auratus and Forsterygion varium, from the time of hatching. Yolk-sac larval P.auratus hatched at a small size (2.00mm SL), without functional eyes, mouth or digestive tract, and for three days spent long periods at rest. Growth was initially rapid but slowed by 3 days as yolk reserves neared depletion. By days 4-5, the mouth had opened, eyes were functional, yolk was depleted, and a rudimentary gut had formed. Larvae were now able to maintain a horizontal swimming mode and were actively searching for and attacking prey. First feeding was observed in some larvae. Growth was retarded during the transition from endogenous to exogenous nutrition and then increased as feeding proficiency improved. Yolk-sac F.varium hatched at a larger size (4.78mm SL), with functional eyes and jaws. Larvae were able to maintain a horizontal swimming mode from hatching. First feeding was observed from the first day after hatching. F.varium larvae grew steadily from the time of hatching. Ocular morphology was examined in larval, juvenile and adult P.auratus and F.varium. There was a 96 fold increase in eye size, from 0.23mm diameter in a 4 day old larval P.auratus (3.4mm SL) to a maximum diameter of 22mm in an adult of 333mm body length. F.varium displayed a 26 fold increase in eye size, from 0.28mm diameter in the smallest larva (5.00mm SL) to a maximum eye diameter of 7.2mm in a 11gmm long adult. Larval fish had pure cone retinae, however putative rod precursor cells were present from hatching in F.varium and from 18 days in P.auratus. Juvenile and adult fish had duplex retinae with cones arranged in a square mosaic in which 4 twin cones surround a central single cone. Hypertrophy of cone ellipsoids with increasing eye size, resulted in maintenance of a closely packed array in fishes of all sizes. The appearance of retinomotor movements was coincident with the development of a duplex retina in both species. Theoretical spatial acuity (calculated as a function of cone spacing and focal length of the lens) was poor in the smallest larval fish (2° 1' and 1° 8' minimum separable angle in 4 and 1 day old P.auratus and F.varium respectively) but improved to asymptotic values in adults (3'- 4', and 9' in P.auratus and F.varium respectively). Behavioural acuity (determined using the optokinetic response) of 4 day old larval P.auratus (37° 30') and 1 day old F.varium (29°) was very much lower than histological estimates. Behavioural acuity improved to 8° 8' in 16 day old P.auratus and 4° 18' in 14 day old F.varium, but did not attain theoretical estimates for fish of that size (55' and 54'). A rudimentary retractor lentis muscle was first apparent in larval fish 1 week after hatching, and was coincident with the formation of a posterior lental space. Presumably larval fish eyes were incapable of accomodative lens movements until this time. A relative measure of Matthiessen's ratio (distance from lens centre to boundary of the pigmented retinal epithelium/lens radius) measured histologically, decreased from 4.2 and 2.7 in 3 day old P.auratus and newly hatched F.varium, to 2.2 and 2.3 in larvae 22 and 16 days of age respectively. This suggests that growth of the retina and lens were not symmetrical in the eyes of very small larval fish. If Matthiessen's ratio holds for little eyes, then they will initially be strongly myopic. This may account in part for the mismatch between behavioural and theoretical acuity. Perceptive distances of first feeding larval P.auratus and F.varium, estimated for prey items equal in dimensions to maximum jaw widths, were very small (0.2mm and 0.4mm for prey 0.15mm and 0.2mm in size respectively), but increased with increasing body size to 2.1mm and 4.0mm for prey 0.3mm in size, at 16 and 14 days of age respectively. These data have implications for larval feeding in the wild.

Beaked whales (family Ziphiidae) are one of the least known of all mammalian groups. The majority of species have been described from only a handful of specimens. Found in deep ocean waters, these species are widespread and often sexually dimorphic. Little is known of intra-specific variation in morphology, and many species are very similar in external appearance. A reference database of mitochondrial DNA sequences was compiled for all 20 recognised ziphiid species to aid in species identification. All reference sequences were derived from validated specimens, which were often represented only by bone or teeth. DNA was obtained from this ‘historic’ material using ‘ancient’ DNA methods. For three species, holotypes were sampled. Phylogenetic analyses using this database led to the discovery of a new, previously unrecognised species of beaked whale (Mesoplodon perrini), new specimens of Longman's beaked whale (Indopacetus pacificus), a species known previously from only two partial skulls and the synonymy of a third (M. traversii = M. bahamondi). Phylogenetic reconstructions based on sequence data from three mitochondrial and two nuclear loci (total, 2815 bp) using neighbour joining, parsimony, and maximum likelihood methods, resolved many of the sister-species relationships in this group. Inferred relationships among Mesoplodon beaked whales indicated that cranial and tooth morphology may be far more variable between closely related species than previously assumed. No support was found for a linear-progression of tooth form as suggested by Moore (1968) in his phenetic evaluation of relationships among the Ziphiidae. The geographic distribution of Mesoplodon species with similar or divergent tooth morphology is likely due to a combination of sexual selection and selection for species recognition. Both hypotheses predict similar patterns, such as dissimilar tooth morphology among species with sympatric or parapatric distributions. However, only sexual selection appears to offer an explanation for why there are so many Mesoplodon beaked whales. Investigation of mtDNA diversity among a number of beaked whale species indicated that nucleotide diversity was generally lower in this group than in other wide-ranging oceanic cetaceans. The cause of this low diversity was not clear but may be indicative of overall low abundance. Particularly low levels of diversity were found in Baird's beaked whale Berardius bairdii , Arnoux's beaked whale B. arnuxii and the northern bottlenose whale Hyperoodon ampullatus. Strong geographic structure in haplotype frequencies was observed among a worldwide sample of Cuvier's beaked whales Ziphius cavirostris. / Subscription resource available via Digital Dissertations only.