New Zealand Species Research Articles

New records of nine monogenean parasites infesting non-native freshwater fish species in New Zealand

ABSTRACT Twenty-one non-native freshwater fish species have established populations in New Zealand, yet only two have been reported with monogenean infestations; grass carp, Ctenopharyngodon idella (Valenciennes in Cuvier and Valenciennes, 1844) and western mosquitofish, Gambusia affinis (Baird and Girard, 1853), each with two identified monogenean species. Based on the diversity of monogeneans known from New Zealand's non-native freshwater fish species in their native and other invaded ranges, it is likely that many other monogeneans could be extant in the country. Accordingly, we surveyed monogeneans from seven freshwater fish species. Eleven monogenean species were found, including nine previously unreported from New Zealand. One represented a genus previously unrecorded in the country, the ancyrocephalid Ligictaluridus pricei (Mueller, 1936), infesting the gills of Ameiurus nebulosus (Lesueur, 1819). Six dactylogyrid monogenean species were found infesting Carassius auratus (L.): Dactylogyrus anchoratus (Dujardin, 1845), D. dulkeiti Bychowsky, 1936, D. formosus Kulweic, 1927, D. inexpectatus Izyumova, 1955, D. intermedius Wegener, 1909 and D. vastator Nybelin, 1924. Further, a Gyrodactylus species was observed from the gills of Carassius auratus, which could not be confidently identified to the species level. Finally, Dactylogyrus minutus Kulweic, 1927, was recorded from Cyprinus rubrofuscus Lacépède, 1803.

Traits associated with the conservation gradient are the strongest predictors of early‐stage fine root decomposition rates

Abstract Fine root traits span two independent axes of variation, the conservation and collaboration axes, which define the root economic space (RES). However, whether early‐stage fine root decomposition rates (quantified as proportion mass loss, i.e. pml) are more strongly related to collaboration or conservation traits remains unclear. We studied 63 tree species in New Zealand's temperate rain forest. We determined the phylogenetic signal in pml and fine root traits, conducted phylogenetic principal component analysis and used phylogenetic generalized least squares to determine which traits are most strongly related to pml. Root decomposition exhibited a high phylogenetic signal and was more strongly related to the conservation than the collaboration axis. Root tissue density (RTD) was negatively correlated and root nitrogen (RN) was positively correlated with pml. Root diameter was positively yet weakly correlated with pml, but specific root length was uncorrelated with pml. The lignin‐to‐N ratio and root cellulose were the strongest predictors of pml. Synthesis: Early‐stage fine root decomposition is most strongly driven by tissue quality traits, such as root nitrogen, tissue density and lignin‐to‐N ratio, which all align with the conservation axis of the root economics space. However, root diameter plays a weak yet undeniable role in early‐stage fine root decomposition. Some thick‐rooted species decomposed faster, possibly due to the higher quality cortical tissue. Thin‐rooted species decomposed slower, possibly because of their higher cellulose concentration that maintains the structural integrity of small diameter roots. Relationships between decomposition and other traits that align with the collaboration gradient deserve further study across the phylogeny of vascular plants.

Spiny lobster recreational fisheries in Australia and New Zealand: An overview of regulations, monitoring, assessment and management

Spiny (rock) lobsters occur globally and, although harvest is dominated by commercial fisheries, it is important to account for recreational harvest in stock assessments and fisheries management. This paper provides a contemporary review of recreational fishing for five spiny lobster species in Australia and New Zealand. Each jurisdiction has established approaches for collecting data which best meet their information needs (telephone-diary or telephone-recall surveys, charter logbooks, tag reporting). Jurisdictions with specific spiny lobster licences (Western Australia, Tasmania) or mandatory reporting (charter logbooks in Western Australia, tag reporting in Victoria) use these registers as a sampling frame for annual reporting of participation, fishing effort, catch (numbers) and harvest (tonnes). All other jurisdictions use a general fishing licence or general population sampling frame for telephone-diary surveys to provide periodic reporting of catch and harvest. Annual participation in spiny lobster recreational fishing was highest in Western Australia (35,236 ± SE 626 fishers in 2022–23), followed by Tasmania (13,715 ± SE 1067 fishers in 2022–23) and Victoria (5516 fishers in 2020–21). Annual recreational harvest of all spiny lobster species, combined for the most recent data collection period in each jurisdiction, was 830 tonnes; consisting mostly of Western Rock Lobster (Panulirus cygnus) from Western Australia and Southern Rock Lobster (Jasus edwardsii) from Tasmania and New Zealand. This review illustrates the various spatial scales of monitoring, reporting and assessment in each jurisdiction. All monitoring provides information on catch and harvest, with some also reporting participation, effort, carapace length and non-catch related variables. The designs underlying these approaches vary from probability-based (opt-out) and census (mandatory), and it is important to understand the benefits and inherent biases of each. Understanding the parallels between jurisdictions offers valuable insights into how to cost-effectively monitor spiny lobster recreational fisheries and integrate this data into stock assessment and harvest strategies to support sustainable fisheries into the future.

Specific leaf area and its within-individual variation in understory evergreen and deciduous woody species in New Zealand

Specific leaf area (SLA) plays a critical role in carbon assimilation and nutrient cycling. While leaf habit (deciduous vs. evergreen) has often been recognized as a reliable predictor of SLA—with deciduous species typically having higher mean SLA values due to lower concentration of structural components compared to evergreens—high variation in SLA among evergreen species suggests further investigation of variation for species with this leaf habit could improve predictions of SLA effects on community and ecosystem processes. Furthermore, the presence of leaves of different ages in evergreen plants, emerging over multiple years, could amplify the within-individual variation in SLA, which remains underexplored. Here we report variations of SLA measured from c. 2000 leaves collected from 36 individuals across 19 woody species in an understory environment in New Zealand (NZ). We found that while most deciduous species, predominantly non-native, clustered towards higher SLA values, evergreen species presented a wide SLA spectrum. Moreover, we found that while being deciduous, having a smaller leaf size, and younger leaves, collected from lateral branches, correlated with elevated SLA values, the leaf habit did not primarily drive the within-individual SLA variation. Instead, smaller leaf size emerged as a significant predictor of within-individual SLA variation. The branch-order effect on SLA underscores a methodological consideration: accurate estimation of total leaf area in evergreen trees requires representative sampling across all branch orders. Our study also highlights the need for integrating leaf traits such as leaf size and branch order into functional trait analyses. Further research is vital to understand the underlying mechanisms of these trait variations and their impacts on ecosystem functioning.

Unlikely allies: Camel crickets play a role in the seed dispersal of an Asian autotrophic shrub

Societal Impact StatementDust seeds, which are minute and contain minimal energy reserves, are often associated with heterotrophy (plants that obtain carbon without photosynthesis). Consequently, previous studies have mainly focused on the relationships between dust seeds and heterotrophy. However, dust seeds are also found in green plants. This manuscript focuses on the seed ecology of the apparently autotrophic shrub Rhynchotechum discolor that produces dust seeds. Using time‐lapse photography, feeding experiments, and germination tests, we show that camel crickets effectively disperse the seeds of this autotrophic shrub. This is the first study to document insect‐mediated internal seed dispersal of an autotrophic plant in regions inhabited by terrestrial mammals, offering new insights into the evolutionary ecology of dust seeds.Summary Although angiosperms exhibit a wide range of seed sizes, the mechanisms driving these differences are poorly understood. The evolution of dust seeds, which contain minimal energy reserves, is traditionally linked to heterotrophy, in which external carbon sources are provided to the embryo or seedling. Dispersal by small animals may be another important but underexplored evolutionary driver of minute seed size. However, insect endozoochory has been documented only in the seeds of heterotrophic species and autotrophic species in New Zealand (i.e., in communities without native terrestrial mammals). Here, we investigate this seed dispersal mechanism in the Japanese shrub Rhynchotechum discolor (Gesneriaceae), which produces white berries with numerous tiny ellipsoid seeds, using time‐lapse photography, feeding experiments, and germination tests, particularly focusing on potential interactions with insect internal seed dispersers. Our time‐lapse photography indicated that camel crickets predominantly feed on fallen fruits of R. discolor. Field sampling revealed that camel crickets excreted numerous intact R. discolor seeds. Feeding experiments confirmed that some camel crickets excreted a high proportion of intact seeds, many of which successfully germinated into autotrophic seedlings. The present study provides the first evidence of insects acting as endozoochorous seed dispersers in fully autotrophic plants within regions inhabited by terrestrial mammals. Our findings suggest that orthopteran‐mediated seed dispersal is more widespread than previously thought, and that dust seeds can evolve from selective pressures beyond heterotrophy, specifically through insect‐mediated seed dispersal.

Nutritional composition of common, coastal seaweeds from northeastern New Zealand

ABSTRACT Seaweeds provide important macronutrients for marine herbivores and potential for aquaculture. However, the nutritional content of most New Zealand seaweeds is undocumented. Here, the nutritional composition of eleven common, littoral seaweed species in northeastern New Zealand was examined using proximate composition analysis. Overall, red seaweeds were highest in protein and insoluble fibre, brown seaweeds were highest in lipids and soluble carbohydrates, and green seaweeds were highest in moisture and ash. More specifically, red seaweeds Asparagopsis armata and Pterocladiella capillacea were highest in protein, while Corallina officinalis was highest in ash and much lower in other macronutrients. Brown seaweeds Carpophyllum maschalocarpum and Cystophora retroflexa were highest in soluble carbohydrates, C. retroflexa was highest in lipids, and Xiphophora chondrophylla was highest in insoluble fibre. Across all species, green seaweeds Codium fragile and Ulva cf. lactuca were highest in moisture. In summary, this study provides a baseline of the nutritional composition of various common seaweeds in northeastern New Zealand, encourages research examining drivers of variability in nutritional composition and highlights commercial opportunities in New Zealand’s burgeoning seaweed sector.

Fungi associated with seeds of the invasive grass Nassella trichotoma (serrated tussock) in its native range as prospective biological control agents

Context The South American grass Nassella trichotoma (serrated tussock) is widely distributed in central Argentina and one of the most damaging invasive species in Australia, New Zealand, and South Africa. In Australia, it is a weed of national significance. Aims Our aim was to characterise the fungi able to colonise N. trichotoma seeds buried at a site in south-western Buenos Aires province, Argentina, and measure their impact on seed survival and germination. Methods We tested the germination of healthy seeds at the beginning of the experiment (control). We buried 10 mesh bags containing 100 disinfected N. trichotoma seeds each, during 3 months in spring and autumn. At the end of each experiment, the contents of five of the bags were counted and classified as germinated, healthy, damaged, or disintegrated. Germination tests were then conducted with seeds of the latter three categories. The remaining seeds were used for recording fungal signs/symptoms, and the isolation of fungi. Key results We identified and described a diverse group of fungi associated with the seeds and a seasonal variation in the specific composition. Seeds showing fungal signs and/or symptoms germinated less than the control. Conclusions This is the first study on fungi associated with seeds of this species in the native range, which can affect their survival and longevity. Implications It is expected that studies on the seed microbiome may help us understand the differences in behaviour of the plant between ranges, and test the enemy-release hypothesis.

A new deep-sea Cristaphyes (Kinorhyncha: Allomalorhagida: Pycnophyidae) from the continental rise of South Island, New Zealand

ABSTRACT A new kinorhynch species, Cristaphyes microtubuliferus sp. nov., is described from the continental rise of South Island, New Zealand. The new species is recognised by the presence of very poorly developed lateral terminal spines, combined with its considerable trunk length, which can exceed 1 mm. In addition, the new species is characterised by morphologically dimorphic setae, i.e. the regular long and slender setae found in most pycnophyid species, and much shorter and more rigid ‘minute setae’. Besides the new species, the presence of two additional undescribed Cristaphyes species is reported. The material is insufficient to support formal species descriptions for the latter two, but short diagnoses are provided for the species. The description of Cristaphyes microtubuliferus sp. nov. brings the total number of described and identified kinorhynch species in New Zealand up to 19. With the new species included, the genus Cristaphyes now accommodates 26 species, of which only six are known from the southern hemisphere. LSID: urn:lsid:zoobank.org:pub: 77FEA91A-7684-4664-9DFC-470A245D9267

Vibrational communication in Scolypopa australis: characterising spontaneous and intrasexual calls in an invasive orchard pest

AbstractVibrational communication in the Auchenorrhyncha is an avenue of growing interest, with many pesticide‐free vibrational pest control programmes against auchenorrhynchan agricultural pests continuing to be developed around the world. Passion vine hoppers (PVH), Scolypopa australis (Walker) (Hemiptera: Ricaniidae), are an economically damaging pest species in New Zealand, where they facilitate the growth of sooty mould in kiwifruit orchards. Scolypopa australis is already known to use vibrational signals, therefore a further understanding of the spectral and temporal characteristics of its calls will be an essential next step to developing vibration‐based pest management strategies. Here, we aimed to characterise the properties of spontaneous S. australis calls in solitary and intrasexual communication contexts. We used laser Doppler vibrometry to record vibrational signals produced by male and female S. australis (separately), when in groups of three or individually. We sorted calls and call sub‐units (syllables) into groups based on cluster analyses of various spatio‐temporal parameters. We define four male calls and three female calls, and newly describe a ‘two‐syllable’ calling structure that may be involved in male intrasexual competition. Certain syllables were more prevalent at the beginning or end of calls for males, and were more homogenously distributed throughout calls for females. The types of calls used differed between single males and groups, with more energetically intense call types observed in the group settings. Additional studies on the behavioural context of S. australis vibrational calls and their responses to playback of such calls will be necessary to assess the viability of vibration‐based pest management for this species.

Population dynamics and prey community of the invasive paper wasp Polistes chinensis (Hymenoptera: Vespidae) in a protected coastal habitat in New Zealand

AbstractThe Asian paper wasp (Polistes chinensis) is an invasive species in New Zealand and a voracious arthropod predator, incorporating a wide range of prey into its diet. We examined the colony survival and prey community composition of these wasps in a protected coastal habitat in New Zealand. Paper wasp colonies at this site were surveyed and monitored weekly over two summers. Our data showed that only ~20% of the monitored colonies each year survived until late summer, with high rates of colony mortality in late spring and early summer. We collected samples of wasp larval guts over a temporal gradient in one nesting season, and via DNA metabarcoding analysis, we identified the prey species consumed. The prey species most frequently identified in larval samples were endemic cicadas and several lepidopteran species. No native arthropod species of known conservation concern were identified in the analysis. However, 63% of the unique taxon sequences retrieved could not be identified by genus or species level, likely due to the absence of reference barcodes. These taxa may represent a group of understudied species, potentially highly endemic or localised. Our analysis indicates that these invasive wasps are opportunistic‐generalist predators with the potential to exert high predation pressure on native arthropods. P. chinensis may be preying on a range of understudied species, especially in remote, natural habitats across New Zealand. We recommend future studies continue to barcode native New Zealand arthropods in order to improve the taxonomic assignments of dietary studies.

International imports and climatic filtering drive compositional variation in non‐native insect establishments

AbstractAimInvasions of non‐native insects can have substantial impacts on agriculture, forestry, human health and biodiversity with considerable economic and environmental consequences. To understand the causes of these invasions, it is important to quantify the relative influence of principal drivers such as international imports and climatic effects.LocationNorth America, Chile, Europe, Australia, New Zealand and Japan.Time Period1881–2020.MethodsTo evaluate the relative contributions of various factors in explaining global variation in numbers of non‐native insect establishments in different world regions, we conducted two multivariate regression analyses to quantify temporal changes in family‐level composition and native ranges of established non‐native species in several world regions.ResultsThere were temporal changes in the family‐level composition of non‐native species assemblages. Prior to 1900, invasions were dominated by scale insects, subsequently shifting to a more diverse set of species, except in North America, which had relatively small compositional change over time compared to other regions. Spatial and temporal variation in the composition of established species was associated with differences in the origin of imports and climatic factors, each explaining 26.3% and 27.4% of the total variation, respectively. The analysis of native ranges of non‐native species indicated that there was no consistent temporal variation across all regions. Established species in New Zealand were predominantly native to Australasia and species in North America and Chile were mainly from Europe. Non‐native species in Europe mainly originated from the Nearctic region while those in Japan and Australia generally originated from multiple regions. Climatic factors in the destination regions had a primary effect (66.3%) on variation in the native range of established species, although imports also had substantial effects (45.4%).Main ConclusionsGeographical variation in climate and imports act together as drivers of establishment success for non‐native insects in all six regions.

Bioluminescence - The Vibrant Glow of Nature and its Chemical Mechanisms.

Bioluminescence, the mesmerizing natural phenomenon where living organisms produce light through chemical reactions, has long captivated scientists and laypersons alike, offering a rich tapestry of insights into biological function, ecology, evolution as well as the underlying chemistry. This comprehensive introductory review systematically explores the phenomenon of bioluminescence, addressing its historical context, geographic dispersion, and ecological significance with a focus on their chemical mechanisms. Our examination begins with terrestrial bioluminescence, discussing organisms from different habitats. We analyze thefireflies of Central Europe's meadows and the fungi in the Atlantic rainforest of Brazil. Additionally, we inspect bioluminescent species in New Zealand, specifically river-dwelling snails and mosquito larvae found in Waitomo Caves. Our exploration concludes in the Siberian Steppes, highlighting the area's luminescent insects and annelids. Transitioning to the marine realm, the second part of this review examines marine bioluminescent organisms. We explore this phenomenon in deep-sea jellyfish and their role in the ecosystem. We then move to Toyama Bay, Japan, where seasonal bioluminescence of dinoflagellates and ostracods present a unique case study. We also delve into the bacterial world, discussing how bioluminescent bacteria contribute to symbiotic relationships. For each organism, we contextualize its bioluminescence, providing details about its discovery, ecological function, and geographical distribution. A special focus lies on the examination of the underlying chemical mechanisms that enables these biological light displays. Concluding this review, we present a series of practical bioluminescence and chemiluminescence experiments, providing a resource for educational demonstrations and student research projects. Our goal with this review is to provide a summary of bioluminescence across the diverse ecological contexts, contributing to the broader understanding of this unique biological phenomenon and its chemical mechanisms serving researchers new to the field, educators and students alike.

New insight into avian malaria vectors in New Zealand

BackgroundMosquitoes (Culicidae) are vectors for most malaria parasites of the Plasmodium species and are required for Plasmodium spp. to complete their life cycle. Despite having 16 species of mosquitoes and the detection of many Plasmodium species in birds, little is known about the role of different mosquito species in the avian malaria life cycle in New Zealand.MethodsIn this study, we used nested polymerase chain reaction (PCR) and real-time PCR to determine Plasmodium spp. prevalence and diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across ten sites on the North Island of New Zealand during 2012–2014. The mosquitoes were pooled by species and location collected, and the thorax and abdomens were examined separately for Plasmodium spp. DNA. Akaike information criterion (AIC) modeling was used to test whether location, year of sampling, and mosquito species were significant predictors of minimum infection rates (MIR).ResultsWe collected 788 unengorged mosquitoes of six species, both native and introduced. The most frequently caught mosquito species were the introduced Aedes notoscriptus and the native Culex pervigilans. Plasmodium sp DNA was detected in 37% of matched thorax and abdomen pools. When considered separately, 33% of abdomen and 23% of thorax pools tested positive by nested PCR. The MIR of the positive thorax pools from introduced mosquito species was 1.79% for Ae. notoscriptus and 0% for Cx. quinquefasciatus, while the MIR for the positive thorax pools of native mosquito species was 4.9% for Cx. pervigilans and 0% for Opifex fuscus. For the overall MIR, site and mosquito species were significant predictors of Plasmodium overall MIR. Aedes notoscriptus and Cx. pervigilans were positive for malaria DNA in the thorax samples, indicating that they may play a role as avian malaria vectors. Four different Plasmodium lineages (SYAT05, LINN1, GRW6, and a new lineage of P (Haemamoeba) sp. AENOT11) were identified in the pooled samples.ConclusionsThis is the first detection of avian Plasmodium DNA extracted from thoraxes of native Culex and introduced Aedes mosquito species in New Zealand and therefore the first study providing an indication of potential vectors in this country.Graphical

Step-point sampling for broadleaved species’ ground cover estimation in pastures – an evaluation of Cockayne’s point on a boot toecap method

ABSTRACT Step-point sampling, conceived by plant ecologist Dr Leonard Cockayne in ca. 1925 as a method for measuring the ground cover of species in New Zealand’s modified tussock grasslands utilises a point marked on the observer’s boot toecap. It is resource-efficient compared to other vegetation sampling methods and here we report on a unique evaluation of its accuracy and precision. The estimated cover of Taraxacum officinale in a grassy field (11%) was not significantly different from that obtained using line-point sampling (13%), but higher than that from line-intercept sampling (5.7%). It was unaffected across an order-of-magnitude range of sampling intensity (1600 to 160 observations/ha) and was acceptably precise with ≥ 400 observations/ha, although increased linearly with observation point size. These empirical results were supported by computer simulations enabling both accuracy and precision to be evaluated along with plant architecture. The simulations indicated that step-point sampling with ca. 400 observations per ha and an observation point diameter ≤ 1.1 cm (1.0 cm2), can provide ground cover estimates for a wide range of broadleaved species in pastures that are sufficiently accurate and precise for common pasture management applications. The method is deployed in the phone application, ‘Grassland Cover Estimator’ available at https://www.agresearch.co.nz/search?q = Grassland + cover + estimator.

Description and molecular data of a new cestode parasite, Cladotaenia anomala n. sp. (Paruterinidae) from the Australasian harrier (Circus approximans Peale) in New Zealand

Currently comprising 12 species infecting the gastrointestinal tracts of diurnal raptors (Falconiformes, Accipitriformes), species of Cladotaenia are diagnosed by their branching uterus, testes in two fields reaching the same level anteriorly, and small rostellum armed with taenioid hooks arranged in two rows. In this study we describe a new species of Cladotaenia recovered from a number of Australasian harriers Circus approximans, from the southern half of South Island, New Zealand. The new species is distinguished from other species by its single circle of hooks. It is closest, morphologically, to C. circi, but differs in the shape of the terminal proglottids and the number of uterine branches. Sequences of 28S and cox1 gene are presented. Genetically, Cladotaenia anomalan. sp. is closest to Cladotaenia globifera but differs morphologically in the size of the suckers, testes and eggs. This description constitutes the first record of a Cladotaenia species in New Zealand. We discuss some potential routes this parasite may have taken to arrive in New Zealand.

Morphometric and meristic discrimination within juvenile flounder species in New Zealand indicate genetic and environmental disparities

ABSTRACT Morphometrics and meristics are measurable and countable traits, respectively, that are under simultaneous control by genetic and/or environmental factors. Resolving morphometric and meristic spatial variation can be a useful technique for identifying population structure and connectivity. The present study investigated morphometric and meristic character variation within three flounder species, sand flounder (Rhombosolea plebeia), greenback flounder (R. tapirina), and yellowbelly flounder (R. leporina) in New Zealand, predominantly in the South Island. Four morphometric measurements and two meristic characters were obtained from 857 juvenile flounder, standardised, and analysed. Consistent with a previous genetic analysis, the differentiation of morphometric and meristic characters supported the idea that sand flounder populations north and south of 42o S were reproductively isolated, and although statistically non-significant, there was an indication that yellowbelly flounder collected from Lake Ellesmere and Orowaiti Lagoon may have been reproductively isolated. Only juvenile sand flounder and greenback flounder were collected in the tidal reaches of estuaries throughout east Otago and the populations are considered undifferentiated based on intra-species morphometric and meristic characters. Our results demonstrated that the influence of environmental variation and adaptive physiology of juvenile flounder likely contributed to the morphometric and meristic variation of individuals among estuaries and years.

New records of Phytoseiidae (Acari: Mesostigmata) in New Zealand, with notes on the occurrence status of some species</p >

This study contributes to the extensive history of research on the family Phytoseiidae in New Zealand, covering nearly a century. We examined phytoseiid specimens in the major repositories, unveiling fifteen species new to New Zealand: Amblyseius andersoni (Chant), A. waltersi Schicha, A. williamsi Schicha, Australiseiulus australicus (Womersley), Euseius elinae (Schicha), Graminaseius graminis (Chant), G. sturti (Schicha), Neoseiulus alpinus (Schweizer), N. californicus (McGregor), N. dieteri (Schicha), N. tareensis (Schicha), Proprioseiopsis anthurii (Schicha), P. cabonus Schicha & Elshafie, P. okanagensis (Chant) and Typhlodromus transvaalensis (Nesbitt), and clarifying the presence or absence status of some species in the country. Additionally, we analysed the diversity and distribution of species in New Zealand, presenting an updated checklist of phytoseiid species in the country.

Flexibility in reproductive attributes may facilitate the invasive capacity of the Mediterranean fanworm, Sabella spallanzanii (Gmelin)

Context The Mediterranean fanworm arrived as a non-indigenous species in parts of Australasia, where it has established and then rapidly spread from the initial points of arrival, despite marked differences in environmental conditions compared from its natal habitat in the Mediterranean Sea. Aims To better understand the invasive capacity of this species in New Zealand. Methods Maturation, reproductive cycle, and gametogenesis were investigated, with a focus on female gamete development, for a population in Auckland, and the results were compared with those of previous studies in the Mediterranean Sea and Australia. Key results Egg sizes in female fanworms were highly variable throughout the year; however, a reduced presence of larger eggs was observed from August to November, which could indicate spawning. This Auckland fanworm population also appeared to have a female-skewed sex ratio compared with previous studies where a 1:1 sex ratio was observed. Fanworm maturation was reached at ~6 cm in length, compared with 15 cm in natal populations. Fanworms with body size smaller than 5 cm were not mature and did not produce mature gametes, in contrast to an Australian fanworm population. Conclusions The observed Mediterranean fanworm population in New Zealand demonstrates reproductive flexibility and high fecundity, contributing to its invasive capacity. Implications The reproductive biology of a species is important in determining its invasive capacity, and may also be flexible between populations, with implications for effective biosecurity management strategies.

Physiological responses of Caulerpa spp. (with different dissolved inorganic carbon physiologies) to ocean acidification

ABSTRACT Caulerpa is a widely distributed genus of chlorophytes (green macroalgae) which are important for their dietary, social and coastal ecosystem value. Ocean acidification (OA) threatens the future of marine ecosystems, favouring macroalgal species that could benefit from increased seawater carbon dioxide (CO2) concentrations. Most macroalgae species possess CO2 concentrating mechanisms (CCMs) that allow active uptake of bicarbonate (HCO3 −). Those species without CCMs are restricted to using CO2, which is currently the least abundant species of dissolved inorganic carbon (DIC) in seawater. Thus, macroalgae without CCMs are predicted to be likely benefit from OA. Caulerpa is one of the rare few genera that have species both with and without CCMs. The two most common Caulerpa species in New Zealand are C. geminata (possesses a CCM) and C. brownii (non-CCM). We investigated the responses of growth, photo-physiology and DIC utilisation of C. geminata and C. brownii to four mean seawater pH treatments (8.03, 7.93, 7.83 and 7.63) that correspond to changes in pH driven by increases in pCO2 simulating future OA. There was a tendency for the mean growth rates for C. brownii (non-CCM) to increase under lower pH, and the growth rates of C. geminata (CCM) to decline with lower pH, although this was not statistically significant. However, this is likely because variability in growth rates also increased as seawater pH declined. There were few other differences in physiology of both species with pH, although there was tendency for greater preference for CO2 over HCO3 − uptake in the CCM species with declining seawater pH. This study demonstrates that DIC-use alone does not predict macroalgal responses to OA.

First records of two mackerel shark species (Carcharodon planus comb. nov. and Carcharodon hubbelli; Lamnidae) from New Zealand

ABSTRACT The fossil record of the genus Carcharodon (Lamniformes: Lamnidae) dates to the late Oligocene and has a near global distribution. Today the genus is represented by a single species, the white shark Carcharodon carcharias. However, multiple extinct species are recognised in the Cenozoic including Carcharodon hastalis, Carcharodon hubbelli and Carcharodon planus comb. nov. Here we present the first occurrences of Carcharodon hubbelli and Carcharodon planus from New Zealand/Aotearoa, from the South Island/Te Waipounamu. Carcharodon hubbelli is previously reported from late Miocene deposits in the Pacific basin of North and South America, Asia, and Australia. Whereas Carcharodon planus has been reported from the Miocene of North America and Asia. One tooth from Carcharodon hubbelli is reported from the presumed late Miocene of Motunau Beach, North Canterbury, while one upper early Miocene tooth recovered from the Kakahu River, South Canterbury and an earliest Miocene tooth from the Big River mouth, Tasman District are referred to Carcharodon planus. In addition to being the first reported occurrences of these two species in New Zealand, the teeth of Carcharodon planus represent some of the earliest occurrences of the taxon as well as its southernmost occurrence.