Differential effects of suspended sediments on larval survival and settlement of New Zealand urchins Evechinus chloroticus and abalone Haliotis iris

10.26686/wgtn.13012997 ◽

2020 ◽

Author(s):

Nicole Phillips ◽

Jeffrey Shima

Keyword(s):

New Zealand ◽

Life History Traits ◽

Sea Urchins ◽

Suspended Sediments ◽

Mortality Rates ◽

Larval Survival ◽

Larval Connectivity ◽

Species Specific ◽

Timing Of Exposure ◽

Dynamics Of Populations

Larvae of marine organisms play an important role in the dynamics of populations, are generally sensitive to environmental stressors, and vary dramatically among species in life history traits. We examined the effects of suspended sediments from terrestrial runoff on larval development, survival, and settlement of New Zealand sea urchins Evechinus chloroticus and abalone Haliotis iris. Larval urchins and abalone were reared under 5 suspended sediment regimes (variable concentrations and timing of exposure, benchmarked against nearby field conditions), and in the absence of sediments. Stage specific per capita mortality rates of urchin larvae increased with concentrations of suspended sediments, and generally, these rates (and the sensitivity of urchin larvae to sediments) decreased with age. Mortality rates of abalone similarly increased in response to sediment concentrations, although older larvae continued to incur high losses when exposed to sediments. Mortality rates of both abalone and urchins increased in response to acute exposure to sediments early in development. For urchins, this effect was immediate and coincident only with exposure to sediments, whereas elevated mortality rates persisted well after the removal of sediments for abalone. Cumulative survival to competency was similar among species and generally decreased with exposure time and/or concentration of sediments. Urchins were twice as likely to settle and metamorphose as abalone but patterns were not related to larval sediment regime for either species. The strong species specific responses to suspended sediments we observe may greatly alter patterns of larval connectivity in marine meta-communities. © Inter-Research 2006.

Download Full-text

Differential effects of suspended sediments on larval survival and settlement of New Zealand urchins Evechinus chloroticus and abalone Haliotis iris

Marine Ecology Progress Series ◽

10.3354/meps314149 ◽

2006 ◽

Vol 314 ◽

pp. 149-158 ◽

Cited By ~ 33

Author(s):

NE Phillips ◽

JS Shima

Keyword(s):

New Zealand ◽

Suspended Sediments ◽

Larval Survival ◽

Differential Effects

Download Full-text

The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

Marine Ecology Progress Series ◽

10.3354/meps13369 ◽

2020 ◽

Vol 650 ◽

pp. 289-308 ◽

Cited By ~ 2

Author(s):

V Raya ◽

J Salat ◽

A Sabatés

Keyword(s):

Field Data ◽

Fish Larvae ◽

Larval Growth ◽

Warming Trend ◽

Mortality Rates ◽

Larval Survival ◽

Pelagic Fish ◽

Balance Model ◽

Small Pelagic Fish ◽

Mesoscale Structures

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

Download Full-text

STOCHASTIC DIFFERENTIAL EQUATION: AN APPLICATION TO MORTALITY DATA

International Journal of Research -GRANTHAALAYAH ◽

10.29121/granthaalayah.v8.i6.2020.538 ◽

2020 ◽

Vol 8 (6) ◽

Author(s):

Rajani P. Agadi ◽

A. S. Talawar

Keyword(s):

Differential Equation ◽

New Zealand ◽

Stochastic Differential Equation ◽

Mortality Rates ◽

Mortality Data

In the present paper we consider an application of stochastic differential equation to model age-specific mortalities. We use New Zealand mortality data for the period 1948–2015 to fit the model. The point predictions of mortality rates at ages 40, 60 and 80 are quite good, almost undistinguishable from the true mortality rates observed.

Download Full-text

Motor neuron disease mortality rates in New Zealand 1992–2013

Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration ◽

10.1080/21678421.2018.1432660 ◽

2018 ◽

Vol 19 (3-4) ◽

pp. 285-293 ◽

Cited By ~ 1

Author(s):

Maize C. Cao ◽

Andrew Chancellor ◽

Alison Charleston ◽

Mike Dragunow ◽

Emma L. Scotter

Keyword(s):

New Zealand ◽

Motor Neuron ◽

Motor Neuron Disease ◽

Mortality Rates ◽

Disease Mortality

Download Full-text

Volatile Profiling of Fifteen Willow Species and Hybrids and Their Responses to Giant Willow Aphid Infestation

Agronomy ◽

10.3390/agronomy10091404 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1404

Author(s):

Kyaw Min Tun ◽

Maria Minor ◽

Trevor Jones ◽

Andrea Clavijo McCormick

Keyword(s):

New Zealand ◽

Sampling Technique ◽

Gas Chromatography Mass Spectrometry ◽

Aphid Infestation ◽

Voc Emission ◽

Willow Species ◽

Plant Chemical ◽

Tuberolachnus Salignus ◽

Volatile Profiles ◽

Species Specific

The giant willow aphid (Tuberolachnus salignus) is a large stem-feeding insect which forms dense colonies on infested plants. Since T. salignus is a new invasive species in New Zealand, we have a poor understanding of the plant chemical responses to aphid infestation. This study aimed to characterize the volatile organic compounds (VOCs) emissions of fifteen different willow species and hybrids growing in New Zealand, and to evaluate changes in response to T. salignus attack in a field trial. Volatiles were collected using a headspace sampling technique and analysed using gas chromatography-mass spectrometry (GC-MS). We found high variability in the volatile profiles of different species and hybrids, with (Z)-3-hexenyl acetate and (E)-β-ocimene being the only common components to all blends. Taxonomically related plants showed an overlapping pattern of VOC emission, and there seemed to be a clear separation between shrub and tree willows. Responses to aphid infestation were variable, with only four species/hybrids showing changes in their total VOC emission, or that of at least one class of VOCs. A weak positive correlation between aphid population estimates and VOC emissions suggests that responses are species-specific and not infestation-dependent. These results reveal useful information about the interaction between T. salignus and its potential host plants for biological control and pest management purposes.

Download Full-text

Explanation for the Decline in Coronary Heart Disease Mortality Rates in Auckland, New Zealand, Between 1982 and 1993

Circulation ◽

10.1161/01.cir.102.13.1511 ◽

2000 ◽

Vol 102 (13) ◽

pp. 1511-1516 ◽

Cited By ~ 132

Author(s):

Simon Capewell ◽

Robert Beaglehole ◽

Mary Seddon ◽

John McMurray

Keyword(s):

Coronary Heart Disease ◽

Heart Disease ◽

New Zealand ◽

Coronary Heart Disease Mortality ◽

Mortality Rates ◽

Disease Mortality

Download Full-text

Individual variability in life-history traits drives population size stability

Current Zoology ◽

10.1093/czoolo/58.2.358 ◽

2012 ◽

Vol 58 (2) ◽

pp. 358-362 ◽

Cited By ~ 6

Author(s):

Ned A. Dochtermann ◽

C. M. Gienger

Keyword(s):

Life History ◽

Life History Traits ◽

Individual Variability ◽

Population Variation ◽

Sceloporus Undulatus ◽

Natural Systems ◽

Size Stability ◽

Population Sizes ◽

The Individual ◽

Dynamics Of Populations

Abstract Understanding how population sizes vary over time is a key aspect of ecological research. Unfortunately, our understanding of population dynamics has historically been based on an assumption that individuals are identical with homogenous life-history properties. This assumption is certainly false for most natural systems, raising the question of what role individual variation plays in the dynamics of populations. While there has been an increase of interest regarding the effects of within population variation on the dynamics of single populations, there has been little study of the effects of differences in within population variation on patterns observed across populations. We found that life-history differences (clutch size) among individuals explained the majority of the variation observed in the degree to which population sizes of eastern fence lizards Sceloporus undulatus fluctuated. This finding suggests that differences across populations cannot be understood without an examination of differences at the level of a system rather than at the level of the individual [Current Zoology 58 (2): 358–362, 2012].

Download Full-text