Multivariate analysis of the spatial species diversity of demersal fish assemblages in relation to habitat characteristics in a subtropical national park, Taiwan

To understand the spatial species diversity of demersal fish assemblages in Taijiang National Park (TJNP) of Taiwan, fishes from 44 demersal trawl hauls and environmental data were collected in the nearshore and offshore areas of TJNP from April 2016 to May 2019. In total, fishes of 47 families, 84 genera, and 113 species were recorded. The nearshore and offshore demersal fish assemblages in TJNP exhibited significant variability in species composition assessed via beta diversity. Using distance-based redundancy analysis, we demonstrated that bottom depth and substrate type were significant explanatory variables of spatial species diversity and identified three habitat types (I: shallow soft bottom; II: deeper soft bottom; III: deeper bottom with mixed sand and gravel substrates). The nearshore assemblage was characterized by type I, where Tarphops oligolepis (flounder), Trachinocephalus myops (snakefish), and Liachirus melanospilos (carpet sole) dominated in terms of abundance. The offshore assemblage was characterized by either type II or type III because differences in substrate types among sampling sites were noticeable. At the offshore sites characterized by a deeper soft bottom (type II), Johnius distinctus (croaker), Cynoglossus kopsii (shortheaded tonguesole), and Coelorinchus formosanus (Formosa grenadier) predominated. In contrast, the westernmost sampling site, characterized by type III habitat, exhibited relatively high Shannon indices, and Scorpaena miostoma (scorpionfish), Urolophus aurantiacus (sepia stingray), and Parabothus taiwanensis (lefteye flounder) predominated. Our results provide the first baseline information on the environmental characteristics and spatial species diversity of demersal fish assemblages in TJNP and have implications for biodiversity conservation in existing spatial management areas.

Lower Eocene (Middle Ilerdian) brachiopods from the Campo region, Central Pyrenees, north-eas tern Spain

Three brachiopod species, Terebratulina tenuistriata (Leymerie, 1846), Argyrotheca vidali (Mallada, 1878), and "Terebratula" n. sp., are recognized in the marls and calcareous silts of the Lower Eocene Puebla Formation of the Campo region in the Central Pyrenees, north-eastern Spain. The rich and well preserved material of T. tenuistriata and A. vidali allows to recognize the range of their morphological variability and to evaluate the status of earlier established species. The investigated assemblage is characterized by the small, pedunculate taxa adapted to life on a soft bottom anchoring directly in a soft substrate or attaching to very small, hard substrates.

Sea cucumber species found in Soft-bottom of Wulan Estuary-Demak, Central Java

Indonesia has been known to have a high diversity of sea cucumber, but data and information are mostly on high-economic-value species. Sea cucumber living in soft-bottom substrates is less studied and unexploited. Wulan estuary located in the Demak Regency of Central Java was experiencing high sedimentation, which was consisted of fine material, and acted as a habitat for many macrozoobenthos, amongst others sea cucumbers. The objective of the present research was to identify the species of sea cucumber in the soft bottom of the Wulan estuary. The collection of sea cucumber specimens was done using a dredge. A total of 132 specimens were collected, examined, and identified through their morphological characters. The holothuroids found in the soft-bottom of the Wulan estuary represent five genera (Acaudina, Colochirus, Holothuria, Paracaudina, Phyllophorus,) in four families (Caudinidae, Cucumariidae, Holothuriidae, and Phyllophoridae) belonging to three orders (Molpadida, Dendrochirotida, and Aspidochirotida). The species were Acaudina sp., A. molpadioides, Colochirus quadrangularis, Holothuria cf. impatiens, Paracaudina sp., Paracaudina chilensis, P. australis, and Phyllophorus spiculata. A. molpadioides is presented as the most frequently found species. Although sea cucumber found in the Wulan estuary has not been exploited, it still needs to be managed to sustain its population.

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

<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>

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

<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>