A new subspecies of Cinctura (Gastropoda: Fasciolariidae) from the Ten Thousand Islands, Florida

A new geographical bathymetric subspecies of the offshore deepwater species Cinctura tortugana (Hollister, 1957) is described from shallow subtidal depths off southwestern Florida. The new subspecies, Cinctura tortugana foxi, is described from offshore of the Ten Thousand Islands, in Collier and Monroe Counties, Florida.

WEATHERING THE STORM: THE IMPLICATIONS OF WAVE EXPOSURE ON THE DISTRIBUTION, PHENOTYPE AND GROWTH OF A TEMPERATE REEF FISH

<p>Disturbance is a fundamental process that affects the structure and dynamics of populations. Wave action is an important agent of disturbance in coastal marine systems, and the frequency and severity of wave-associated disturbances is forecasted to increase with climate change. Understanding the effects of waves on coastal marine ecosystems, and the ability of organisms to adapt to wave action, is of growing importance. This is particularly true for intertidal/shallow subtidal species that are subjected to varying, sometimes intense, wave action. Most studies to-date have focused on species with limited mobility (e.g., algae and invertebrates), and have used estimates of wave dynamics that are not always relevant to the spatial scales of these organisms and their home ranges. My thesis focuses on the common triplefin, Forsterygion lapillum, an abundant benthic marine fish inhabiting shallow subtidal and intertidal rocky reefs throughout New Zealand. I develop and implement a protocol to characterise wave climates on an ecologically relevant scale. I evaluate the effects of waves on abundance, phenotype, performance, and behaviour of a reef fish. In Chapter 2, I develop and implement a protocol to characterise wave climate at an appropriate scale. The Wellington south coast is exposed to storm waves that develop in the Southern Ocean and propagate up the east coast of New Zealand. I deployed low-cost HOBO acceleration loggers at two depths within each of six locations along the Wellington south coast to record a time series of wave action at twelve sites. Data from my loggers showed substantial spatial and temporal variation in water acceleration due to interactions between waves and local topography. I used a clustering analysis to characterise my 12 sites as either ‘exposed’ or ‘sheltered’. Assignments to these exposure categories did not match with a priori predictions of exposure, suggesting that wave forces experienced by organisms in the shallow subtidal environment may be difficult to assess from surface-based observations of waves. Data were generally well-correlated with an offshore buoy at all sites, and these correlations were stronger for more exposed sites. In Chapter 3, I explored variation in fish density and phenotype through time and as a function of wave exposure. Densities peaked in summer (corresponding to seasonal recruitment) and declined over winter (consistent with increased losses during high-wave periods), and were generally greater at sheltered locations. While body condition was generally highest for fish sampled from exposed sites (consistent with a density-dependent effect on condition and/or enhancement of foraging with increasing water acceleration), other morphological characteristics did not consistently vary with wave exposure. In Chapter 4, I used otoliths to reconstruct of growth histories of individuals to further elucidate the influence of wave exposure on triplefin phenotypes. Recent growth was not influenced by wave exposure, but this was confounded by strong seasonal variation in growth rates. Lifetime growth rate also did not differ with wave exposure, and was strongly influenced by hatch date. I used mixed effects models to appropriately account for the potentially confounding effects of other features on growth, and found that daily growth rates were slightly positively correlated with site-specific daily measures of wave action. This result can potentially account for the elevated body condition of fish at exposed sites (Chapter 3), and it has important implications for fish inhabiting wave exposed coasts. In Chapter 5, I conducted a lab experiment to evaluate feeding ability in relation to simulated wave action. I used fish of a range of sizes, sampled from either a wave-sheltered or a wave-exposed site, and measured their consumption of prey in calm (low flow) conditions, disturbance (high flow) conditions, and immediately following a period of disturbance. Fish consumed fewer prey during disturbance, and more prey during calm conditions (and a similar consumption rate was observed for fish that were assayed after a period of intense wave action). While this pattern held for fish sampled from both populations, fish from wave-exposed sites consumed more prey than fish from sheltered sites, suggesting phenotypic traits (e.g., behavioural or morphological) that shape their feeding efficiency. Collectively my results suggest that organisms that inhabit wave-exposed coastlines may be intimately linked to wave climate. Waves may have direct effects on numbers (reducing densities via induced mortality) and/or indirect effects on the traits, foraging opportunities, and/or body condition of survivors. Species such as the common triplefin may exhibit plasticity in phenotypic traits that enable them to adapt to dynamic and unpredictable environments. Overall, this thesis provides insight into the ability of an intertidal/shallow subtidal species to cope with variable wave action. Such species may exhibit resilience with increasing wave action due to climate change.</p>

WEATHERING THE STORM: THE IMPLICATIONS OF WAVE EXPOSURE ON THE DISTRIBUTION, PHENOTYPE AND GROWTH OF A TEMPERATE REEF FISH

<p>Disturbance is a fundamental process that affects the structure and dynamics of populations. Wave action is an important agent of disturbance in coastal marine systems, and the frequency and severity of wave-associated disturbances is forecasted to increase with climate change. Understanding the effects of waves on coastal marine ecosystems, and the ability of organisms to adapt to wave action, is of growing importance. This is particularly true for intertidal/shallow subtidal species that are subjected to varying, sometimes intense, wave action. Most studies to-date have focused on species with limited mobility (e.g., algae and invertebrates), and have used estimates of wave dynamics that are not always relevant to the spatial scales of these organisms and their home ranges. My thesis focuses on the common triplefin, Forsterygion lapillum, an abundant benthic marine fish inhabiting shallow subtidal and intertidal rocky reefs throughout New Zealand. I develop and implement a protocol to characterise wave climates on an ecologically relevant scale. I evaluate the effects of waves on abundance, phenotype, performance, and behaviour of a reef fish. In Chapter 2, I develop and implement a protocol to characterise wave climate at an appropriate scale. The Wellington south coast is exposed to storm waves that develop in the Southern Ocean and propagate up the east coast of New Zealand. I deployed low-cost HOBO acceleration loggers at two depths within each of six locations along the Wellington south coast to record a time series of wave action at twelve sites. Data from my loggers showed substantial spatial and temporal variation in water acceleration due to interactions between waves and local topography. I used a clustering analysis to characterise my 12 sites as either ‘exposed’ or ‘sheltered’. Assignments to these exposure categories did not match with a priori predictions of exposure, suggesting that wave forces experienced by organisms in the shallow subtidal environment may be difficult to assess from surface-based observations of waves. Data were generally well-correlated with an offshore buoy at all sites, and these correlations were stronger for more exposed sites. In Chapter 3, I explored variation in fish density and phenotype through time and as a function of wave exposure. Densities peaked in summer (corresponding to seasonal recruitment) and declined over winter (consistent with increased losses during high-wave periods), and were generally greater at sheltered locations. While body condition was generally highest for fish sampled from exposed sites (consistent with a density-dependent effect on condition and/or enhancement of foraging with increasing water acceleration), other morphological characteristics did not consistently vary with wave exposure. In Chapter 4, I used otoliths to reconstruct of growth histories of individuals to further elucidate the influence of wave exposure on triplefin phenotypes. Recent growth was not influenced by wave exposure, but this was confounded by strong seasonal variation in growth rates. Lifetime growth rate also did not differ with wave exposure, and was strongly influenced by hatch date. I used mixed effects models to appropriately account for the potentially confounding effects of other features on growth, and found that daily growth rates were slightly positively correlated with site-specific daily measures of wave action. This result can potentially account for the elevated body condition of fish at exposed sites (Chapter 3), and it has important implications for fish inhabiting wave exposed coasts. In Chapter 5, I conducted a lab experiment to evaluate feeding ability in relation to simulated wave action. I used fish of a range of sizes, sampled from either a wave-sheltered or a wave-exposed site, and measured their consumption of prey in calm (low flow) conditions, disturbance (high flow) conditions, and immediately following a period of disturbance. Fish consumed fewer prey during disturbance, and more prey during calm conditions (and a similar consumption rate was observed for fish that were assayed after a period of intense wave action). While this pattern held for fish sampled from both populations, fish from wave-exposed sites consumed more prey than fish from sheltered sites, suggesting phenotypic traits (e.g., behavioural or morphological) that shape their feeding efficiency. Collectively my results suggest that organisms that inhabit wave-exposed coastlines may be intimately linked to wave climate. Waves may have direct effects on numbers (reducing densities via induced mortality) and/or indirect effects on the traits, foraging opportunities, and/or body condition of survivors. Species such as the common triplefin may exhibit plasticity in phenotypic traits that enable them to adapt to dynamic and unpredictable environments. Overall, this thesis provides insight into the ability of an intertidal/shallow subtidal species to cope with variable wave action. Such species may exhibit resilience with increasing wave action due to climate change.</p>

Faunal composition and paleoenvironmental reconstruction of a Middle–Late Triassic boundary assemblage in the Pyrenean basin (Catalonia, NE Spain)

The Ladinian–Carnian transition in the Tethys domain was accompanied by an important environmental change representing a milestone in the climate evolution of the Triassic. However, estimations on paleodiversity composition and paleoenvironmental conditions across this interval are scarce in marine settings due to the lack of fossil-bearing successions. In this work, a refined paleontological and sedimentological study has allowed us to better characterize a well-preserved marine ?Ladinian–Carnian carbonate succession in the South Central Pyrenees (Odèn site, Catalonia, NE Spain). Vertebrate faunas include numerous actinopterygian specimens, forming an assemblage composed of at least four taxa: Peltopleurus cf. P. nuptialis Lombardo, 1999, Saurichthys sp., Colobodus giganteus (Beltan, 1972), and an indeterminate halecomorph. Specimens belonging to the genus Peltopleurus are dominant; the long-snouted Saurichthys, the halecomorph, and the large-bodied Colobodus giganteus are less abundant. Tetrapod remains are scarcely present and are assigned to sauropterygians. Invertebrate faunas include bivalves (Pseudocorbula gregaria [Münster in Goldfuss, 1838]) and brachiopods (Lingula sp.). The fossil assemblage was recovered from organic-rich laminated silty mudstone layers. Sedimentological and textural analyses suggest that fossil biotas were deposited below the fair-weather wave base in shallow subtidal coastal settings. These environments were sporadically sourced by silt/clay. The age of the Odèn site, on the basis of the recovered fauna, is assigned to the ?late Ladinian–middle Carnian (Middle–Late Triassic), which is in agreement with previously published ages based on palynomorph data. The refined integration of paleontological, sedimentological, and biostratigraphic data from the Odèn site and other vertebrate-bearing localities in the Tethys domain can help better constrain the paleoenvironmental conditions and paleogeographical configuration impacting ecosystem diversity during the late Ladinian–Carnian interval.

A new species of Polyophthalmus (Annelida, Opheliidae) from the Arabian Gulf, with an insight on internal anatomy and diversity of the genus

Polyophthalmus zhadanae sp. nov. (Annelida, Opheliidae), is described from the coast of Kuwait and Saudi Arabia (Arabian Gulf) after specimens collected in the intertidal and shallow subtidal. This new species is characterised by the body pigmentation pattern, distribution of lateral eyes, presence of small dorsal and ventral parapodial cirri and pygidial features. External and internal anatomy was described after examination with SEM and micro-CT. The presence of several body structures in the genus such as a cephalic palpode-like papilla is discussed. Furthermore, the diversity of genus Polyophthalmus and the presence of Polyophthalmus pictus (Dujardin, 1839) in the Indo-Pacific is reviewed and a key to species is provided.

Inter-island local adaptation in the Galápagos Archipelago: genomics of the Galápagos blue-banded goby, Lythrypnus gilberti

The Galápagos Archipelago is a place where terrestrial adaptive radiations of finches, mockingbirds, and tortoises have been studied extensively. In contrast, little is known about the potential for marine species to diverge among islands. The overall degradation of coral reefs in the Galápagos makes understanding the mechanisms and factors of speciation, the engine of biodiversity, important, and timely. While speciation in marine archipelagos has been described in the past, such as for cone snails in Cabo Verde Archipelago and limpets in Hawaii, adaptive radiations in the marine environment are still rare and poorly understood. In this study, we focused on the Galápagos blue-banded goby, Lythrypnus gilberti, a small endemic fish that is found in shallow subtidal rocky habitats. Using RAD sequencing, we analyzed 19,504 loci that were either neutral, or potentially under directional selection. As expected, considering the small geographic range, population structure based on neutral markers was weak. For loci under directional selection, however, marked differences between islands suggested potential for local adaptation. Our data suggest that for marine species, where dispersal barriers are less apparent, mechanisms of local adaptation may also be at play in the Galápagos Archipelago.

Invasive Fucus serratus (Fucaceae, Phaeophyceae) responds to climate change along the Atlantic Coast of Nova Scotia, Canada

The distribution and ecology of the invasive brown alga Fucus serratus along the 500 km Atlantic coast of Nova Scotia, Canada, has been poorly explored. We observed significant intertidal penetration at four sites in the southwestern part of the province, and then examined numerous sites along the Atlantic coast of Nova Scotia. Surveys of attached algae in intertidal and shallow subtidal zones and wrack show that F. serratus has become a dominant plant in the low to mid-intertidal zone and can be expected on headlands along the South Shore of Nova Scotia where it can occupy up to 40% of the intertidal zone with cover >75% and mean densities of up to 10 kg m−1. In this zone, F. serratus has replaced Chondrus crispus as the major canopy species, although C. crispus and Corallina officinalis remain primary understory species. At slightly higher elevations, F. serratus was common as an understory beneath Ascophyllum nodosum and Fucus vesiculosus. While geographic spread along the Atlantic coast might reflect the natural dispersal capacity of F. serratus, we hypothesize that the ecological extension into the intertidal zone may be facilitated by harvesting of A. nodosum and by climate change in an ocean-warming hotspot.