Reproduction of paua, Haliotis iris Gmelin 1791 (Mollusca:Gastropoda), in north-eastern New Zealand

1995 ◽  
Vol 46 (3) ◽  
pp. 617 ◽  
Author(s):  
SH Hooker ◽  
RG Creese

An examination of the reproductive condition of a population of paua, H. iris, at Leigh in north-eastern New Zealand during 1986-87 revealed a long breeding season extending from late summer through autumn and winter and into early spring. Within this period, a sharp decrease of over 60% in the gonad index for both males and females indicated major spawning events in July and October. A smaller decrease in the gonad index in March suggested a third, minor spawning. These spawning events were confirmed by regular examination of histological sections of gonadal material. This breeding pattern is different from that previously described for southern localities in New Zealand, where spawning activity is limited to a four-month period from late summer into autumn. Paua in this northern population had a sex ratio slightly biased towards males (1 female to every 1.3 males) and achieved reproductive maturity between the sizes of 48 and 60 mm shell length. These features are also different from those described for southern populations of H. iris. These findings highlight the need to take regional differences in reproductive pattern into account when describing the population dynamics of marine gastropods.

1953 ◽  
Vol 20 (1) ◽  
pp. 76-100 ◽  
Author(s):  
A. K. R. McDowell ◽  
F. H. McDowall

Results of a survey of the carotene and vitamin A contents, and of the vitamin A potency, of New Zealand butterfat and butter, are presented. The butter samples were drawn from twenty representative commercial factories at fortnightly intervals over three successive years (1946–8). The survey covers the analysis of 1517 samples of fresh butter and 670 samples of stored butter.There were uniform and regularly recurring seasonal variations in both carotene and vitamin A contents of butterfats from all North Island districts. Maximum values were found in the late-autumn/winter/early-spring, and minimum values in the late-summer/early-autumn butterfats. The seasonal trends were thus distinctly different from those which have been reported for northern hemisphere butterfats, for which the maximum values are commonly found during the summer grazing period.The seasonal variations in carotene and vitamin A contents of South Island butterfat were less marked and less consistent than those in the corresponding values for North Island butterfat.


Author(s):  
M. V. Carter

Abstract A description is provided for Eutypa armeniacae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: As a pathogen on apricot (Prunus armeniaca) and Ceanothus spp. As a saprophyte on apricot (Prunus armeniaca), almond (Prunus amygdalus[Prunus dulcis]), apple (Malus sylvestris, walnut (Juglans regia), grapevine (Vitis vinifera), tamarisk (Tamarix sp.), Ceanothus spp. and Berberis darwinii. DISEASE: 'Gummosis' or 'dieback' of apricots in Australia (Adam et al., 1952). 'Cytosporina dieback' of apricots in California (42, 474). A contributing factor to the syndrome known as 'apricot apoplexy' in various European countries (Carter, private communications). Dieback of Ceanothus spp. in Australia and California (Moller et al., 1971). The dieback disease of apricots is also known to be associated with this pathogen in New Zealand (40, 88) and South Africa (Price, 1973). On apricot, the classical symptoms occur on trees of all ages: cankering, sometimes associated with exudation of gum, in the vicinity of wounds which expose the sapwood, most commonly those made by pruning instruments. Ultimately the leaves on the part of the branch distal to the canker wither and die, usually in mid- to late summer, typically remaining attached for many months because no abscission layer has formed. Internally, the sapwood is discoloured light brown to dark brown, with a dffluse margin. Pycnidia may appear, usually in winter, on wood and bark nearby advanced infections. The pycnidiospores have never been seen to germinate and appear to have no role in transmission of the pathogen. Perithecia are immersed in a stroma which may develop two or more years after death of a branch. The stroma may remain productive for at least six years, producing one generation of perithecia annually, maturing in early spring. In California and in South Africa, external canker symptoms were for many years confused with those caused by bacteria or the genus Pseudomonas, but the internal symptoms are usually quite distinctive and the presence of E. armeniacae has been confirmed by culturing and by serology. GEOGRAPHICAL DISTRIBUTION: Australia, New Zealand, North America (California), Europe (France, Spain, Switzerland), South Africa. Absent from Chile in a disease survey conducted by English et al. (1967). Absence of records from the Asian continent are attributed to lack of information. TRANSMISSION: Entirely by air-borne ascospores; secondary dispersal from the tree surfaces is by water-splash and run during rainfall, carrying ascospores to the vessels exposed at wounds (45, 511).


2019 ◽  
Vol 96 (1133) ◽  
pp. 139-143 ◽  
Author(s):  
Qian Wu ◽  
Zhiwei Xu ◽  
Yi-Lin Dan ◽  
Chan-Na Zhao ◽  
Yan-Mei Mao ◽  
...  

ObjectiveAlthough patients with psoriasis frequently report seasonal changes in their symptoms, the seasonality of psoriasis has rarely been explored. This study aims to investigate the seasonal pattern of and global public interest in psoriasis using Google search data.MethodsInternet search data were collected from Google Trends. Data on the relative search volume (RSV) from January 2004 to December 2018 were retrieved using the term psoriasis. Cosinor analyses were conducted to examine the seasonality of psoriasis using data from two southern hemisphere countries (Australia and New Zealand) and four northern hemisphere countries (USA, Canada, UK and Ireland).ResultsOverall, searches for psoriasis steadily decreased between 2004 and 2010, and then rose from 2011 to 2018. On cosinor analyses, RSV of ‘psoriasis’ displayed a significant seasonal variation worldwide (p<0.025). Further analyses confirmed the seasonality of psoriasis-related RSV in Australia, New Zealand, USA, Canada, UK and Ireland (p<0.025 for all), with peaks in the late winter/early spring months and troughs in the late summer/early autumn months. The top 11 rising topics were calcipotriol/betamethasone dipropionate, ustekinumab, apremilast, shampoo, eczema, guttate psoriasis, seborrhoeic dermatitis, dermatitis, psoriatic arthritis, atopic dermatitis and arthritis.ConclusionThere was a significant seasonal pattern for psoriasis, with peaks in the late winter/early spring and troughs in the late summer/early autumn. Further studies are warranted to confirm the seasonal pattern of psoriasis using clinical data and to explore the underlying mechanisms.


Author(s):  
D. Scott ◽  
J.F.L. Charlton

Observations in trials over a decade are now showing that birdsfoot trefoil (Lotus corniculatus) has the particular characteristics of high persistency and continued production under moderate soil fertility conditions on drier hill and high country sites. Hence it may have a role in the agriculture of such areas, probably as late summer or autumn feed. The species is seen as a 'poorer land grazing lucerne' rather than as a hay species as it is overseas. One particular disadvantage is likely to be its slow establishment from seed. In evaluations of introductions and overseas cultivars, some of the unselected introductions, showing early spring growth and an upright habit, performed better than cultivars. Keywords: Birdsfoot trefoil; Lotus corniculatus; infertile hill country; lucerne


Author(s):  
Francisco Benítez-Villalobos ◽  
Maritza Martínez-García

The starfishPharia pyramidatusis a tropical species of high ecological importance, mainly because of its role as generalist predator. Nevertheless, there are no studies about its reproduction. This study analysed the reproductive biology ofP. pyramidatusbased on monthly time-series samples from April 2008 to March 2009 at Isla Montosa in the Mexican tropical Pacific. The gonad index (GI), and pyloric caecum index (PCI) were determined and the results were corroborated by histological examination of the gonads.Pharia pyramidatusis a gonochoric asteroid and the ratio of males to females was not significantly different throughout the year. Gametogenesis showed high synchrony among males and females and five stages were recognized for both sexes. Spawning occurred from July to September. Maximum oocyte size was ~150μm and mean fecundity was 7.3 ± 1.2 millions of oocytes per female. GI and PCI showed seasonal variations and an inverse relationship from May to August. Sea-bottom temperature and photoperiod showed a direct relationship with GI, and apparently constitute the proximate causes of the seasonal reproductive pattern observed inP. pyramidatus, while the highly seasonal rainfall and strong upwelling probably act as ultimate causes.


2005 ◽  
Vol 56 (8) ◽  
pp. 1107 ◽  
Author(s):  
G. A. Thompson ◽  
C. L. McLay

The Belliidae are a small family of crabs whose relationships with other families are enigmatic and whose composition is controversial. It is by no means certain whether their genera form a monophyletic group. One member of this family is Heterozius rotundifrons, a New Zealand endemic crab that lives in the intertidal zone, sheltering under rocks. In the present study the mating behaviour of this species was examined under laboratory conditions. Mating and moulting are closely linked because H. rotundifrons females only mate immediately after moulting. Females remain attractive to males for almost 3 days. A female-derived water-borne pheromone seems to be the basis of this attraction. Prior to moulting males guard females for up to 5 days. During the female moult some males were observed to assist the female. During copulation both males and females exhibited an unusual limb quivering behaviour and afterwards males guarded the females for 10.5 h, which was extended to 37 h when other males were present. Field studies showed that females moulted during early spring over a period of 1 month. Throughout the year very few females moulted, suggesting that there may be intense competition for mates during the early spring. At all times the operational sex ratio was biased in favour of males. In terms of the evolution of reproductive characters among the Belliidae, Atelecyclidae, Cheiragonidae and Corystidae, H. rotundifrons occupies an intermediate position between the ancestral condition and that seen in Corystes cassivelaunus.


1983 ◽  
Vol 63 (4) ◽  
pp. 973-979 ◽  
Author(s):  
JERRY M. BASKIN ◽  
CAROL C. BASKIN

Seeds of fall panicum (Panicum dichotomiflorum Michx.) were buried in fine-mesh nylon bags in soil and exposed to the annual temperature cycle. Fresh seeds and seeds exhumed after 1–15 mo were tested in light and darkness at five temperature regimes simulating those in the field from early spring through late autumn. Freshly matured seeds were dormant, but they came out of dormancy during late autumn and winter. Thus, by spring (April) seeds germinated to near 100% in light at 20/10, 25/15, 30/15 and 35/20 °C. However, except at 35/20 °C during June, July and August, the majority of the seeds required light for germination. In the field, germination does not begin until April when temperatures come within the range of those required for germination. Seeds retained the ability to germinate to a high percentage at 30/15 and 35/20 °C throughout the summer, but they lost this ability at 20/10 °C in early summer and at 25/15 °C in late summer. Thus, seeds stop germinating in early autumn when diurnal field temperatures decrease below about 20–25 °C maximum and 10–15 °C minimum. In autumn, seeds lost the ability to germinate even at the high temperatures, but they regained it by the following January.Key words: Germination, dormancy, after-ripening, fall panicum, summer annual, buried seeds


1986 ◽  
Vol 26 (3) ◽  
pp. 297 ◽  
Author(s):  
CR Stockdale

The influence of time of first irrigation (mid-February, early March, or late March) on the productivity of an annual pasture was studied for 3 years in northern Victoria. Beginning the irrigation of annual pastures in late summer instead of at the normal time of late March- April provided additional herbage in autumn and winter and did not adversely affect herbage production in late winter-early spring; up to 2.3 t/ha DM of additional herbage was obtained by mid June and 4.3 t/ha DM over the whole season. Earlier irrigation also increased the subterranean clover content of the pasture, resulting in herbage that was lower in digestibility and higher in nitrogen content than that in the other treatments. The benefit of early irrigation in increasing clover content may be offset by invasion by weeds. In this experiment, a potential weed problem in the earliest irrigation treatment appeared at the beginning of year 3.


Author(s):  
David H. Sample' ◽  
Henry M. Bartholomew ◽  
R.Marc Sulc

Eleven cereal rye (&cafe cereale) cultivars, one triticale (Triticum secale) and one winter wheat (Triticum aestivum) cultivar were evaluated in 2 studies for their ability to extend the grazing season into the autumn and winter in southern Ohio. The cultivars, 5 in 1993 and 9 in 1994, were randomly assigned to replicated plots and planted in late summer. Plots were harvested in late autumn to determine dry matter (DM) yield and forage quality. Results from the two years indicate significant differences (P=O.O5) between cultivars for DM yield, crude protein(CP) and NDF levels. DM yields ranged from 1389 to 2470 kg/ha (1993) and 1018 to 2 124 kg/ha (1994). Crude protein levels ranged from 25.2 to 27.9% (1993) and 28.8 to 33.7% (1994). A second harvest of the 1994 plots was made in early spring 1995 for continued evaluation. Statistically significant differences again existed between the stockpiled cultivars. DM yields ranged from 1979 to 2980 kg/ha while crude protein levels ranged between 21.5 and 27.0% of DM. Results support the conclusion that selected cereal rye cultivars can produce excellent yields of high quality forage for late autumn and winter grazing in the Ohio climate. Keywords: cereal rye, extended grazing season, Secale cereale, triticale, wheat


2021 ◽  
Author(s):  
Gerard van der Schrier ◽  
Richard P. Allan ◽  
Albert Ossó ◽  
Pedro M. Sousa ◽  
Hans Van de Vyver ◽  
...  

Abstract. The European drought of 1921 is assessed in terms of its impacts on society and in terms of its physical characteristics. The development of impacts of the drought are categorized by a systematic survey of newspaper reports from five European newspapers covering the area from England to the Czech Republic and other parts of Europe. This is coupled to a reconstruction of daily temperature and precipitation based on (rescued) meteorological measurements to quantify the drought severity and extent, and reanalysis data is used to identify its drivers. This analysis shows that the first impacts of the drought started to appear in early spring and lingered on until well into autumn and winter, affecting water supply and agriculture and livestock farming. The dominant impact in western Europe is on agriculture and livestock farming while in central Europe the effects of wildfires were reported on most often. The peak in the number of reports is in late summer. Preceeding the first impacts was the dry autumn of 1920 and winter 1920/1921. The area hardest hit by the drought in the following spring and summer was the triangle between Brussels, Paris and Lyon, but a vast stretch of the continent, from Ireland to the Ukraine, was affected. The reported impacts on water supply and water borne transport in that region were matched by an analysis of the hydrological situation over the Seine catchment. On average, the 1921 summer was not particularly hot but the heat wave which was observed at the end of July saw temperatures matching those of the heatwaves in modern summers. Similar to modern droughts, an anticyclone was present roughly over the British Isles, maintaining sunny and dry weather in Europe and steering away cyclones to the north. Its persistence makes it exceptional in comparison to modern droughts. The 1921 drought stands-out as the most severe and most wide-spread drought in Europe since the start of the 20th century. While none of the seasons in 1920 and 1921 tops the scale of having the largest precipitation deficit on record, the conservative nature of drought amplifies the lack of precipitation in autumn and winter into the following spring and summer.


Sign in / Sign up

Export Citation Format

Share Document