PROBING FOR STRONTIUM PATTERNS IN OTOLITHS OF COMMON BULLIES FROM THE CLUTHA RIVER, NEW ZEALAND

2002 ◽  
Vol 12 (03n04) ◽  
pp. 109-115 ◽  
Author(s):  
A. MARKWITZ ◽  
B. BARRY ◽  
G. CLOSS ◽  
M. SMITH

Common bullies, Gobiomorphus cotidianus, are a widespread small New Zealand freshwater fish, with a life-cycle that may include an optional juvenile marine phase. We used the strontium variation in fish otoliths in an attempt to track the life history of the individual fish since the interlayer variation reflect the exposure of fish to background environmental levels of Sr at the time of deposition. One possible mechanism by which Sr can be enriched in otoliths is by seawater, which usually has a higher Sr/Ca ratio than fresh water. Locally resolved elemental measurements with a proton microprobe enable therefore the detection of variation in Sr that may reflect single or multiple migrations of freshwater fish into seawater. The most striking feature of this study is the observation of high Sr/Ca ratios in the cores of all otoliths, including those from fish caught 50 km inland. This suggests different environments in the life cycle of common bullies in the lower reaches of the Clutha river. A marine juvenile phase may be a common feature. Preliminary area scans were used to select suitable transects for detailed line scans which gave greatly improved statistics.

1978 ◽  
Vol 52 (1) ◽  
pp. 51-59 ◽  
Author(s):  
R. Madhavi

ABSTRACTThe life history of Allocreadium fasciatusi which occurs in the intestine of a freshwater fish Aplocheilus melastigma has been worked out in detail. The snail Amnicola travancorica acts as the first intermediate host. The miracidium hatching out from the eggs attacks the snail and passes through two generations of rediae. Cercariae are of ophthalmoxiphidiocercous type with very long tail and are identical to Cercariae Indicae XLIX Sewell, 1922. The cercariae penetrate and develop into metacercariae in the haemecoel of the copepods Mesocyclops leuckarti, Microcyclops varicans and Marcocyclops distructus. Upon ingestion by the definitive host, the metacercariae excyst and develop into adults. All the stages in the life cycle are described and the life cycle is compared with other allocreadiid life cycles. The original description of A. fasciatusi is revised and Psilostomum chilkai Chatterji, 1956 from Lates calcalifer is synonymized with it.


1978 ◽  
Vol 52 (3) ◽  
pp. 251-259 ◽  
Author(s):  
R. Madhavi

ABSTRACTThe life cycle of Genarchopsis goppo a hemiurid trematode found in the stomach of Channa punctata has been worked out in detail. The egg contains a fully developed miracidium at the time of liberation. The miracidium contains a ciliated covering, a long apical gland and a crown of spines at the anterior end. The snail Amnicola travancorica acts as the first intermediate host inside which the miracidium passes through sporocyst and redial generations. The cercaria is of cystophorous type and is identical to Cercariae Indicae Sewell XXXV. Metacercaria occurs in the ostracods Stenocypris malcolmsoni and Eucyoris capensis. The fish Aplocheilus panchax serves as the paratenic host. The entire developmental cycle from egg to egg producing adult takes 3 months.


2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Esethu Monakali

This article offers an analysis of the identity work of a black transgender woman through life history research. Identity work pertains to the ongoing effort of authoring oneself and positions the individual as the agent; not a passive recipient of identity scripts. The findings draw from three life history interviews. Using thematic analysis, the following themes emerge: institutionalisation of gender norms; gender and sexuality unintelligibility; transitioning and passing; and lastly, gender expression and public spaces. The discussion follows from a poststructuralist conception of identity, which frames identity as fluid and as being continually established. The study contends that identity work is a complex and fragmented process, which is shaped by other social identities. To that end, the study also acknowledges the role of collective agency in shaping gender identity.


Author(s):  
Axel Michaels

This chapter examines the classical Hindu life-cycle rites, the term saṃskāra and its history, and the main sources (Gṛhyasūtras and Dharma texts). It presents a history of the traditional saṃskāras and variants in local contexts, especially in Nepal. It describes prenatal, birth and childhood, initiation, marriage, old-age, death, and ancestor rituals. Finally, it analyzes the transformational process of these life-cycle rituals in the light of general theories on rites of passage. It proposes, in saṃskāras, man equates himself with the unchangeable and thus seems to counteract the uncertainty of the future, of life and death, since persons are confronted with their finite existence. For evidently every change, whether social or biological, represents a danger for the cohesion of the vulnerable community of the individual and society. These rituals then become an attempt of relegating the effects of nature or of mortality: birth, teething, sexual maturity, reproduction, and dying.


Author(s):  
J. B. Brown-Gilpin

The wide variety of reproductive patterns and behaviour in the many species of Nereidae already studied clearly justifies further research. But the life history of Nereis fucata (Savigny) is not only of interest from the comparative point of view. Its commensal habit (it occurs within shells occupied by hermit crabs) immediately gives it a special importance. This alone warrants a detailed study, particularly as no commensal polychaete has yet been reared through to metamorphosis and settlement on its host (Davenport, 1955; Davenport & Hickok, 1957). The numerous interesting problems which arise, and the experimental methods needed to study them, are, however, beyond the range of a paper on nereid development. It is therefore proposed to confine the present account to the reproduction and development up to the time when the larvae settle on the bottom. The complete life cycle, the mechanism of host-adoption, and related topics, will be reported in later papers.


1953 ◽  
Vol 31 (4) ◽  
pp. 351-373 ◽  
Author(s):  
Liang-Yu Wu

A cause of swimmer's itch in the lower Ottawa River is Trichobilharzia cameroni sp. nov. Its life cycle has been completed experimentally in laboratory-bred snails and in canaries and ducks, and the various stages are described. The eggs are spindle-shaped. The sporocysts are colorless and tubular. Mother sporocysts become mature in about a week. The younger daughter sporocyst is provided with spines on the anterior end and becomes mature in about three weeks. The development in the snail requires from 28 to 35 days. A few cercariae were found to live for up to 14 days at 50 °C., although their life at 16° to 18 °C. was about four days. Cercariae kept at room temperature for 60 to 72 hr. were found infective. The adults become mature in canaries and pass eggs in about 12 to 14 days. Physa gyrina is the species of snail naturally infected. It was found in one case giving off cercariae for five months after being kept in the laboratory. Domestic ducks were found to become infected until they were at least four months old, with the parasites developing to maturity in due course; no experiments were made with older ducks. Furthermore, miracidia were still recovered from the faeces four months after the duck had been experimentally infected, and it is suggested that migratory birds are the source of the local infection.


1878 ◽  
Vol 27 (185-189) ◽  
pp. 481-485

Notwithstanding the numerous and fruitful researches which have been recently made into the life-history of Bacteria, our knowledge of the common and interesting curved and spiral forms— the Vibrio and Spirillum of Ehrenberg—has made little or no advance since his time, neither embryonic nor reproductive forms having ever been observed; while even the zooglœa phase, so characteristic of Bacterium and Bacillus, has only once been mentioned, and then in a different form. A fresh-water aquarium, which has been stagnating since last summer in the Physiological Laboratory of University College, con­tained in winter vast numbers of ordinary motile Spirillum. On recently re-examining the water, one zooglœa film after another having in the meantime formed on the surface, thickened, broken, and sunk, we found that these motile forms had almost disappeared, while the films consisted almost entirely of resting Spirillum in a gelatinous-looking matrix, similar to that of Bacterium and Bacillus . Among these were two or three apparently distinct kinds of filaments, some resting and colourless, others motile, and filled with highly refracting bright yellowish-brown spheres. Such a field is represented in fig. 1.


2013 ◽  
Vol 88 (2) ◽  
pp. 230-236 ◽  
Author(s):  
R. Brinesh ◽  
K.P. Janardanan

AbstractThe life-cycle stages of Pleurogenoides malampuzhensis sp. nov. infecting the Indian bullfrog Hoplobatrachus tigerinus (Daudin) and the skipper frog Euphlyctiscyanophlyctis (Schneider) occurring in irrigation canals and paddy fields in Malampuzha, which forms part of the district of Palakkad, Kerala, are described. The species is described, its systematic position discussed and compared with the related species, P. gastroporus (Luhe, 1901) and P. orientalis (Srivastava, 1934). The life-cycle stages, from cercaria to egg-producing adult, were successfully established in the laboratory. Virgulate xiphidiocercariae emerged from the snail Digoniostoma pulchella (Benson). Metacercariae are found in muscle tissues of dragonfly nymphs and become infective to the frogs within 22 days. The pre-patent period is 20 days. Growth and development of both metacercariae and adults are described.


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