scholarly journals Population structure, temporal stability and seascape genetics of two endemic New Zealand Pleuronectiformes, Rhombosolea plebeia (sand flounder) and R. leporina (yellowbelly flounder)

2021 ◽  
Author(s):  
◽  
Heather B. Constable
Keyword(s):  
Population Structure ◽  
New Zealand ◽  
Coastal Waters ◽  
Population Genetic ◽  
East Coast ◽  
Temporal Stability ◽  
Soft Bottom ◽  
The South ◽  
Management Options ◽  
Genetic Patterns

<p>New Zealand’s coastal waters are an integral part of the social, economic and environmental heritage of this Pacific archipelago. Evolving in isolation for 82 million years under volatile tectonic action and volcanism, the marine biogeography of New Zealand is complex and diverse. Many hypotheses have been proposed to explain the subdivisions of biogeographic areas based on species distributions, habitat and population genetics. In this study, I test whether there is differentiation in coastal population connectivity between northern and southern provinces, the location of the break and what environmental factors may explain the patterns observed.  Sandy, soft bottom and estuarine ecosystems make up a large proportion of the coastline, but are not well-represented in population genetic studies in New Zealand and internationally. I chose Rhombosolea leporina (sand flounder) and Rhombosolea plebeia (yellowbelly flounder) as endemic, commercially and traditionally important inhabitants of the shallow coastal waters and estuaries to explore levels of gene flow among most of the marine biogeographic regions of the New Zealand mainland.  The goal of this thesis research was to (1) develop polymorphic DNA microsatellite markers and (2) investigate the population genetic patterns at multiple spatial scales. Although these species have a relatively long pelagic larval duration (PLD) of ~70 days, I found a significant level of population structure for both species. There was a pattern of isolation by distance and a north to south break in connectivity on the east coast for R. plebeia, but an east to west disjunction in R. leporina. There was no evidence of a north to south genetic break in R. leporina, however populations on the south east coast of the South Island were significantly differentiated in both species.  A test for temporal effects (3) of genetic variation was conducted to determine whether spatial patterns of differentiation were consistent across multiple sampling seasons and age classes. Aspects of the sweepstakes recruitment success (SRS) hypothesis were tested by examining differences in allele frequencies and levels of genetic diversity as a function of time. The analyses found evidence of temporal stability between years and between juveniles and adults.  Lastly, (4) the coastal and estuarine environmental variables were modelled using information from two public GIS datasets and several measures of genetic differentiation. The aim of this chapter was to determine which environmental and geospatial factors showed a significant level of correlation with the spatial genetic patterns reported in the earlier studies. For R. leporina, latitude, sediment and current speeds were significantly correlated with the genetic estimates of FST, F’ST and Jost’s D. In R. plebeia, a correlation was found between latitude, longitude, sediment, current speeds, sea surface temperature and width of the estuary mouth. The results of the modelling study suggest avenues for further research using candidate genes, such as heat shock proteins and rhodopsin.  This was the first study of New Zealand pleuronectids using a multidisciplinary approach with microsatellite DNA markers, GIS, and an array of bioinformatics software to study coastal connectivity on multiple spatial and temporal scales. Significant genetic structuring was found among populations of animals that are potentially well connected through continuous sandy, soft bottom environments and a long PLD. Despite similar life histories and ecologies, the two species were quite divergent in that there was little cross amplification of markers, different patterns of genetic structure and separate outcomes from environmental modelling. These results suggest that managing several species under one management plan may be an oversimplification of the complexities of the population dynamics and evolutionary histories of these species. Conservation and management options for coastal fisheries and possible avenues for future research are proposed.</p>

scholarly journals Population structure, temporal stability and seascape genetics of two endemic New Zealand Pleuronectiformes, Rhombosolea plebeia (sand flounder) and R. leporina (yellowbelly flounder)

2021 ◽  
Author(s):  
◽  
Heather B. Constable
Keyword(s):  
Population Structure ◽  
New Zealand ◽  
Coastal Waters ◽  
Population Genetic ◽  
East Coast ◽  
Temporal Stability ◽  
Soft Bottom ◽  
The South ◽  
Management Options ◽  
Genetic Patterns

<p>New Zealand’s coastal waters are an integral part of the social, economic and environmental heritage of this Pacific archipelago. Evolving in isolation for 82 million years under volatile tectonic action and volcanism, the marine biogeography of New Zealand is complex and diverse. Many hypotheses have been proposed to explain the subdivisions of biogeographic areas based on species distributions, habitat and population genetics. In this study, I test whether there is differentiation in coastal population connectivity between northern and southern provinces, the location of the break and what environmental factors may explain the patterns observed.  Sandy, soft bottom and estuarine ecosystems make up a large proportion of the coastline, but are not well-represented in population genetic studies in New Zealand and internationally. I chose Rhombosolea leporina (sand flounder) and Rhombosolea plebeia (yellowbelly flounder) as endemic, commercially and traditionally important inhabitants of the shallow coastal waters and estuaries to explore levels of gene flow among most of the marine biogeographic regions of the New Zealand mainland.  The goal of this thesis research was to (1) develop polymorphic DNA microsatellite markers and (2) investigate the population genetic patterns at multiple spatial scales. Although these species have a relatively long pelagic larval duration (PLD) of ~70 days, I found a significant level of population structure for both species. There was a pattern of isolation by distance and a north to south break in connectivity on the east coast for R. plebeia, but an east to west disjunction in R. leporina. There was no evidence of a north to south genetic break in R. leporina, however populations on the south east coast of the South Island were significantly differentiated in both species.  A test for temporal effects (3) of genetic variation was conducted to determine whether spatial patterns of differentiation were consistent across multiple sampling seasons and age classes. Aspects of the sweepstakes recruitment success (SRS) hypothesis were tested by examining differences in allele frequencies and levels of genetic diversity as a function of time. The analyses found evidence of temporal stability between years and between juveniles and adults.  Lastly, (4) the coastal and estuarine environmental variables were modelled using information from two public GIS datasets and several measures of genetic differentiation. The aim of this chapter was to determine which environmental and geospatial factors showed a significant level of correlation with the spatial genetic patterns reported in the earlier studies. For R. leporina, latitude, sediment and current speeds were significantly correlated with the genetic estimates of FST, F’ST and Jost’s D. In R. plebeia, a correlation was found between latitude, longitude, sediment, current speeds, sea surface temperature and width of the estuary mouth. The results of the modelling study suggest avenues for further research using candidate genes, such as heat shock proteins and rhodopsin.  This was the first study of New Zealand pleuronectids using a multidisciplinary approach with microsatellite DNA markers, GIS, and an array of bioinformatics software to study coastal connectivity on multiple spatial and temporal scales. Significant genetic structuring was found among populations of animals that are potentially well connected through continuous sandy, soft bottom environments and a long PLD. Despite similar life histories and ecologies, the two species were quite divergent in that there was little cross amplification of markers, different patterns of genetic structure and separate outcomes from environmental modelling. These results suggest that managing several species under one management plan may be an oversimplification of the complexities of the population dynamics and evolutionary histories of these species. Conservation and management options for coastal fisheries and possible avenues for future research are proposed.</p>

The discovery of a new sedimentary basin: offshore Raukumara, East Coast, North Island, New Zealand

2008 ◽  
Vol 48 (1) ◽  
pp. 53 ◽  
Author(s):  
Chris Uruski ◽  
Callum Kennedy ◽  
Rupert Sutherland ◽  
Vaughan Stagpoole ◽  
Stuart Henrys
Keyword(s):  
New Zealand ◽  
Oil And Gas ◽  
East Coast ◽  
Plate Boundary ◽  
Source Rocks ◽  
Fault System ◽  
Northern Coast ◽  
The South ◽  
Petroleum Potential ◽  
The North

The East Coast of North Island, New Zealand, is the site of subduction of the Pacific below the Australian plate, and, consequently, much of the basin is highly deformed. An exception is the Raukumara Sub-basin, which forms the northern end of the East Coast Basin and is relatively undeformed. It occupies a marine plain that extends to the north-northeast from the northern coast of the Raukumara Peninsula, reaching water depths of about 3,000 m, although much of the sub-basin lies within the 2,000 m isobath. The sub-basin is about 100 km across and has a roughly triangular plan, bounded by an east-west fault system in the south. It extends about 300 km to the northeast and is bounded to the east by the East Cape subduction ridge and to the west by the volcanic Kermadec Ridge. The northern seismic lines reveal a thickness of around 8 km increasing to 12–13 km in the south. Its stratigraphy consists of a fairly uniformly bedded basal section and an upper, more variable unit separated by a wedge of chaotically bedded material. In the absence of direct evidence from wells and samples, analogies are drawn with onshore geology, where older marine Cretaceous and Paleogene units are separated from a Neogene succession by an allochthonous series of thrust slices emplaced around the time of initiation of the modern plate boundary. The Raukumara Sub-basin is not easily classified. Its location is apparently that of a fore-arc basin along an ocean-to-ocean collision zone, although its sedimentary fill must have been derived chiefly from erosion of the New Zealand land mass. Its relative lack of deformation introduces questions about basin formation and petroleum potential. Although no commercial discoveries have been made in the East Coast Basin, known source rocks are of marine origin and are commonly oil prone, so there is good potential for oil as well as gas in the basin. New seismic data confirm the extent of the sub-basin and its considerable sedimentary thickness. The presence of potential trapping structures and direct hydrocarbon indicators suggest that the Raukumara Sub-basin may contain large volumes of oil and gas.

Seasonal and Inter‐Annual Variability of SST off the East Coast of the South Island, New Zealand

1999 ◽  
Vol 14 (3) ◽  
pp. 29-34 ◽  
Author(s):  
A. G.P. Shaw ◽  
L. Kavalieris ◽  
R. Vennell
Keyword(s):  
New Zealand ◽  
East Coast ◽  
The South ◽  
Annual Variability

Population structure, growth and longevity of Placostylus hongii (Pulmonata: Bulimulidae) on Tawhiti Rahi Island, Poor Knights Islands, New Zealand

2003 ◽  
Vol 9 (4) ◽  
pp. 241 ◽  
Author(s):  
I. A. N. Stringer ◽  
Karl E. C. Brennan ◽  
Melinda L. Moir ◽  
G. R. Parrish ◽  
Jonathan D. Majer ◽  
...  
Keyword(s):  
Population Structure ◽  
New Zealand ◽  
Shell Length ◽  
East Coast ◽  
Snail Species ◽  
Snail Population ◽  
Predator Control ◽  
Juvenile Period ◽  
Harmonic Radar ◽  
The Poor

Placostylus hongii, a threatened snail species, was studied on Tawhiti Rahi Island in the Poor Knights Islands group off the east coast of northern New Zealand between 1998 and 2000. Most live snails and empty shells were adults (83% and 85% respectively) and the low proportion of empty adult shells (36%) compared with live adult snails found in an area last burnt in the late 1950s suggests that the population there is still recovering. Growth was measured using snails recaptured with the aid of harmonic radar transponders attached to their shells. Increase in shell length varied from 6 to 25 mm per year in juveniles with shells >38 mm long, but it slowed when juveniles approached maturity (adult shell length 55-89 mm). The juvenile period is greater than three years and growth in shell length virtually stops when a thick aperture lip develops. This lip continues to thicken at 0.1-0.4 mm per year and can reach a maximum thickness of 15.5 mm, indicating that adults may live 10 years and possibly more than 30 years. A comparison of our data with two previous studies on the same population and on Aorangi Island, in the Poor Knights Islands group, confirms that these snails are slow developing, have low recruitment of adults, and that populations are probably maintained by a pool of long-lived adults. Our results indicate that following predator control on the mainland, the recovery of a snail population is likely to be slow. Once a population has recovered it could be maintained by intensively controlling rodents for periods of greater than three years (to allow recruitment of adults into the population) alternating with longer periods without control.

scholarly journals Population genetic structure and connectivity patterns of the kanae (Mugil cephalus) in New Zealand inland and coastal waters

2021 ◽  
Author(s):  
◽  
Angel Jimenez Brito
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Gene Flow ◽  
New Zealand ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Coastal Waters ◽  
Population Genetic ◽  
Mugil Cephalus ◽  
Connectivity Patterns

<p>Mugil cephalus is a cosmopolitan fish species found in most coastal waters from tropical to temperate zones. It is a species common in the near-shore marine environment, and known to reside in estuarine and freshwater systems. Adult M. cephalus move out to sea to spawn in aggregations. Their larvae can drift on surface ocean currents for over a month before recruitment to nursery grounds. Mugil cephalus is a species that is closely associated with the coastal environment, but it is capable of interoceanic migrations. Population genetic studies have reported high levels of genetic differentiation among populations in the Mediterranean, Atlantic and western Pacific. However, there is no evidence to suggest reproductive incompatibility has arisen among populations. In New Zealand M. cephalus supports important recreational, commercial and customary fisheries, but very little is known about the distribution and connectivity among populations.  The aim of this study was to use nuclear microsatellite DNA (msatDNA) and mitochondrial DNA (mtDNA) markers to describe the population genetic structure, connectivity patterns and to determine the phylogeographic history of New Zealand M. cephalus populations. Total of 850 samples were collected (576 adults and 274 juveniles) during the summers of 2010 and 2014-2015 from 15 locations around coastal and inland waters of the North Island, and one location in Marlborough Sounds. In addition, 245 mtDNA sequences were added from previously published studies and used to outgroup the New Zealand population and place it into the context of the other Pacific populations.  Seven msatDNA loci were isolated and used to determine the population genetic structure and connectivity patterns of M. cephalus in New Zealand. Admixture of four genetically distinct groups or populations was identified and a chaotic spatial distribution of allele frequencies. Within each population there was significant gene flow among locations, no pattern of genetic isolation-by-distance was identified and there was a high proportion of non-migrant individuals. There was evidence of bottlenecks and seasonal reproductive variation of adults, which could explain the significant shifts in the effective population size among locations.  To test whether the pattern of genetic variation in M. cephalus populations was the result of seasonal variability in the reproductive success of adults, DNA from adult and juvenile samples were used to test for differences in the levels of genetic variation between generations (cohorts). Juveniles were grouped by age classes and compared to the adults. The levels of genetic diversity within the groups of juveniles were compared to the adult population and significant genetic bottlenecks between juveniles and adults were detected. This pattern was consistent with the Sweepstake-Reproductive-Success hypothesis. Two spawning groups in the adults were identified, an early spawning group and a late spawning group.  The analysis of DNA sequence data from the mtDNA Cytochrome Oxidase subunit 1 (COX1) gene and D-loop region showed two sympatric haplogroups of M. cephalus. New Zealand was most likely colonised by M. cephalus migrants from different population sources from the Pacific first ~50,000 and a second wave of migrants from Australia between ~20, 000 and ~16,000 years ago. High levels of gene flow were detected, but there has not been enough time for genetic drift to completely sort the lineages.  The findings of this thesis research will help with the understanding of aspects of M. cephalus dispersal and the genetic structure of populations. The patterns of connectivity can be used to better align the natural boundaries of wild populations to the fishery management stock structure. Understanding the reproductive units, levels of genetic diversity and the patterns of reproduction of M. cephalus will assist management efforts to focus on the key habitats threats, risks and the long-term sustainability of the species.</p>

Population genetic structure of barramundi (Lates calcarifer) across the natural distribution range in Australia informs fishery management and aquaculture practices

2019 ◽  
Vol 70 (11) ◽  
pp. 1533 ◽  
Author(s):  
Shannon R. Loughnan ◽  
Carolyn Smith-Keune ◽  
Luciano B. Beheregaray ◽  
Nicholas A. Robinson ◽  
Dean R. Jerry
Keyword(s):  
Population Structure ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Fishery Management ◽  
Captive Breeding ◽  
Temporal Stability ◽  
Fixation Index ◽  
Lates Calcarifer ◽  
Land Bridge

Clarifying population structure of fish stocks is important for the sustainable exploitation of fisheries, along with informing collection of founder broodstock for the genetic improvement of aquaculture programs. Using 16 microsatellite DNA markers, the most comprehensive genetic survey to date (1297 individuals from 49 sample collections) of the population structure and genetic diversity of wild Australian barramundi (Lates calcarifer) was undertaken. The results point to the existence of two distinct genetic stocks (east and west) with isolation by geographic distance (IBD), and a central region of admixture between the stocks, located in an area where a historic land bridge once connected northern Australia with Papua New Guinea. Global levels of population differentiation were moderate (fixation index, FST=0.103, P&lt;0.001) and IBD was identified as a factor influencing population structure across the sampled region. There was also evidence of temporal stability of population genetic structure over a period of 25 years. This study provides valuable information for improving programs of translocation, restocking and captive breeding for both the wild barramundi fishery and the aquaculture industry.

Description of two new species of Dysidea (Porifera, Demospongiae, Dictyoceratida, Dysideidae) from Tauranga Harbour, Bay of Plenty, New Zealand

Zootaxa ◽  
2020 ◽  
Vol 4780 (3) ◽  
pp. 523-542 ◽  
Author(s):  
SAMUEL P. MC CORMACK ◽  
MICHELLE KELLY ◽  
CHRISTOPHER N. BATTERSHILL
Keyword(s):  
New Species ◽  
New Zealand ◽  
East Coast ◽  
Exclusive Economic Zone ◽  
The South ◽  
The North ◽  
Fresh Material ◽  
Two New Species ◽  
Northeast Coast

Differentiation of species within the genus Dysidea Johnston, 1842 (Order Dictyoceratida Minchin, 1900, Family Dysideidae Gray, 1867) is extremely difficult as they lack spicules which are strongly diagnostic in other Demospongiae, and their primary and secondary fibres and the mesh that they form, may be irregular in shape and thickness, thus difficult to measure for comparisons. Here we review species of Dysidea known from the New Zealand Exclusive Economic Zone (EEZ), validating five species: Dysidea cristagalli Bergquist, 1961a, from the Hauraki Gulf; D. hirciniformis (Carter, 1885a) sensu Dendy (1924), from North Cape; D. navicularis Lendenfeld, 1888, from Port Lyttleton on the east coast of the South Island; D. ramsayi (Lendenfeld, 1888) from the Chatham Islands; D. spiculivora Dendy, 1924, from Cape Maria Van Diemen and the Three Kings Islands to the north of New Zealand. Dysidea fragilis (Montagu, 1818) sensu Bergquist (1961b), from Mernoo Bank on Chatham Rise, is now considered to be invalid, and D. elegans (Nardo, 1847) sensu Brøndsted (1927), from the Coromandel Peninsula, is considered unrecognisable. Several partially characterised species have also been cited in the literature. Two new species from Tauranga Harbour, on the northeast coast of the North Island, Dysidea tuapokere sp. nov. and D. teawanui sp. nov., are described. These descriptions are based on fresh material and in situ photography, facilitating clear, informative descriptions, that will enable ease of identification of these species in the future. 

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