Reproductive capacity morphometrically assessed in Cancer pagurus from the Shetland Islands

2002 ◽  
Author(s):  
S.M.L. Tallack
Keyword(s):  
Reproductive Capacity ◽  
Shetland Islands ◽  
Cancer Pagurus

Size–fecundity relationships for Cancer pagurus and Necora puber in the Shetland Islands, Scotland: how is reproductive capacity facilitated?

2007 ◽  
Vol 87 (2) ◽  
pp. 507-515 ◽  
Author(s):  
Shelly M.L. Tallack
Keyword(s):  
Reproductive Output ◽  
Carapace Width ◽  
Reproductive Potential ◽  
Reproductive Capacity ◽  
Size At Maturity ◽  
Successful Management ◽  
Shetland Islands ◽  
Cancer Pagurus ◽  
Linear Relationships ◽  
Spawning Stock

Successful management of fishery resources is dependent on understanding the exploited species' reproductive potential, which, in turn, requires spatially relevant estimates of the size at maturity and the size–fecundity relationship. This information is used by fisheries managers to implement regional maturity-based legal landings sizes and seasonal fishery closures aimed at protecting the spawning stock and maintaining the reproductive output of the fished population at a sustainable level, despite exploitation. Crab fisheries in particular depend on such information, which is often limited, even in long-established fisheries. To address this issue, size–fecundity relationships were obtained for two commercially exploited crabs in waters around the Shetland Islands (60°N 01°W). These species were Cancer pagurus and Necora puber. A statistically significant positive size–fecundity relationship was found for C. pagurus which describes a mean reproduction potential ranging from ~0.78 million eggs in females of 129 mm carapace width (CW) to ~2.4 million eggs in females of 212 mm CW. The positive size–fecundity relationship found for N. puber was not statistically significant, but describes a mean reproduction potential ranging from ~0.16 million eggs in females of 56 mm CW to ~0.19 million eggs in females of 96 mm CW. Morphometric assessments of reproductive capacity in C. pagurus support the notion that positive size–fecundity relationships are attributable to the combined capacities of specific morphological features, each of which contributes to a female's spawning output ability. Statistically significant positive linear relationships were found between the natural logarithms of crab size (CW) and pleopod capacity, sperm plug mass, spermathecae capacity and gonad capacity. Respectively, these structures are crucial for successful egg attachment and incubation, sperm retention and protection, sperm storage and oogenesis.

The reproductive cycle and size at maturity observed in Cancer pagurus in the Shetland Islands, Scotland

2007 ◽  
Vol 87 (5) ◽  
pp. 1181-1189 ◽  
Author(s):  
Shelly M.L. Tallack
Keyword(s):  
Reproductive Cycle ◽  
Carapace Width ◽  
Biological Indicators ◽  
Size At Maturity ◽  
Mating Period ◽  
Spawning Period ◽  
Functional Maturity ◽  
Shetland Islands ◽  
Egg Capsules ◽  
Cancer Pagurus

Seasonality of the reproductive cycle for Cancer pagurus was determined using three biological indicators: extruding sperm plugs (mating period), extrusion of eggs (spawning period) and presence of empty egg capsules (hatching period). Sperm plugs were found only in recently moulted females, indicating that mating coincides with moulting periods. Cancer pagurus mating indicators were observed during the summer months and into autumn; spawning occurred in winter, and broods were hatching throughout the summer into early autumn. Size at maturity, was assessed using a variety of reproductive and morphometric criteria; estimates from reproductive criteria are generally larger than those from morphometric criteria and these differences are often indicative of ‘functional’ vs ‘behavioural’ maturity. In C. pagurus, size at maturity estimates ranged from 101.6–125.0 mm carapace width (CW) in males and 110.7–147.3 mm CW in females; the sizes at functional maturity proposed are larger than those from morphometric indicators.

Distribution and reproductive capacity of Deschampsia antarctica and Colobanthus quitensis on Byers Peninsula, Livingston Island, South Shetland Islands, Antarctica

2013 ◽  
Vol 25 (2) ◽  
pp. 292-302 ◽  
Author(s):  
María Luisa Vera ◽  
Teresa Fernández-Teruel ◽  
Antonio Quesada
Keyword(s):  
Seed Production ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Reproductive Capacity ◽  
South Shetland Islands ◽  
Deschampsia Antarctica ◽  
Shetland Islands ◽  
Colobanthus Quitensis ◽  
Livingston Island ◽  
Viable Seeds

AbstractThe Maritime Antarctic is one of the regions where regional climate change is most intense and the reproductive performance of plants may be enhanced. Reporting the distribution of Deschampsia antarctica and Colobanthus quitensis on Byers Peninsula (Livingston Island, South Shetland Islands), our results confirm that D. antarctica is more widespread than C. quitensis. Flower and seed development of both species varied between sites. Deschampsia antarctica produced more viable seeds than C. quitensis, although fully developed seeds were not found at all locations. Seed production in C. quitensis was low in comparison with other Antarctic locations. The largest cushions of Colobanthus observed in 2002 were 15 cm in diameter, suggesting that the populations may have established at least 50 years ago. Deschampsia antarctica tussocks were very often 20 cm in diameter, although turf areas up to 1.5 m across were also observed, probably due to coalesced aggregates of individuals. This study shows that, although seed production is low, the presence of seedlings and young individuals suggests an expansion process.

Ultrastructural Effects of Acute Kepone Treatment in Rats

1976 ◽  
Vol 34 ◽  
pp. 286-287
Author(s):  
Richard L. Klein ◽  
Åsa K. Thureson-Klein ◽  
Harihara M. Mehendale
Keyword(s):  
Neurological Disorders ◽  
Corn Oil ◽  
Preliminary Investigation ◽  
Reproductive Capacity ◽  
Ultrastructural Changes ◽  
Lipid Deposition ◽  
Severe Toxicity ◽  
Sprague Dawley ◽  
Ether Anesthesia ◽  
Sprague Dawley Rats

KeponeR (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) is an insecticide effective against ants and roaches. It can cause severe toxicity in fishes, birds, rodents and man. Prominent effects include hepatic lipid deposition and hypertrophy, impairment of reproductive capacity and neurological disorders. Mitochondrial oligomycin-sensitive Mg2+-ATPase is also inhibited. The present study is a preliminary investigation of tissue ultrastructural changes accompanying physiological signs of acute toxicity, which after two days treatment include: pronounced hypersensitivity and tremor, various degrees of anorexia and adipsia, and decreased weight gain.Three different series of adult male Sprague-Dawley rats (Charles River or CD-I) were treated by intubation with Kepone in corn oil at a dose of 50 mg per kg for 3 successive days or at 200 ppm in food for 8 days. After ether anesthesia, rats were immediately perfused via a cannula in the left ventricle with 4% p-formaldehyde and 0.5% glutaraldehyde in Millonig's phosphate buffer at pH 7.2 for 20-30 min at 22°C.

Contextualisation and typology of disc-headed and trapezoidal gravemarker forms in Scotland

2012 ◽  
Vol 34-35 (1) ◽  
pp. 1-24
Author(s):  
George Thomson
Keyword(s):  
Cultural Evolution ◽  
Shetland Islands ◽  
Small Disc

Two distinctive small funerary artefact types, disc-headed and trapezoidal gravemarkers, are described. Both are uncommon in Scotland. Small disc-headed gravemarkers are distributed throughout the country but, with two exceptions, trapezoidal gravemarkers are restricted to the Shetland Islands. All known examples of these objects, including some not previously reported, are detailed and discussed in the context of similar artefacts in the rest of Britain and Europe. The current confusion in the use of names for these marker types and their variants is addressed and, through the construction of two separate typologies, a practical taxonomy is suggested. It is also suggested that both these gravemarker forms may represent examples of convergent cultural evolution.

FINDING FACTORS OF SURVIVAL THE YOUNG OF MARINE HERRING MIGRATING IN THE NORTHERN PART OF THE CASPIAN SEA

2017 ◽  
pp. 19-25
Author(s):  
Tatiana Stanislavovna Zubkova
Keyword(s):  
First Generation ◽  
Environmental Influence ◽  
Reproductive Capacity ◽  
Individual Species ◽  
Survival Ratio ◽  
The Caspian Sea ◽  
Foraging Area ◽  
Starting Point ◽  
Feeding Assessment ◽  
Predatory Fishes

The objects of research are three species of Caspian migrating herrings (Dolginsk herring ( Alosa brashnikowi ), big-eyed shad ( Alosa saposchnikowii ), Caspian shad ( Alosa caspia caspia )). The work considers two biological aspects of herring reproduction: dependence of number of underyearlings on the number of females in the end of feeding; assessment of survival rate of herring juveniles from the stage of fish egg to the stage of underyearlings. Besides fecundity of individual species, scientists take into account sex ratio in spawning populations, population fecundity, loss of reproductive capacity due to the resorption in unscreened roe. The materials obtained within 2009-2015 show that the dependence of herring underyearling number on the number of females arriving at spawning ground is extremely low. Despite a great number of females on the spawning grounds, the reasons of decreasing number of the first generation can be different: unfavorable hydrological and hydrochemical environment in foraging area, insufficient nutritive base, rescheduling of the spawning etc. The varying number of underyearlings from year to year is more pronounced with predatory fishes: the Dolginsk herring - 2.1 times, big-eyed shad - 1.7 times. The underyearling number of zoo-plankton feeder - Caspian shad is consistently high with minimal yearly variations. The young of Caspian shad have the highest survival ratio (0.0122); the young of predatory herring species the ratio is lower: Dolginsk herring is 4 times less (0.0031), big-eyed shad - 5 times less (0.0024). The data on herring survival from stage of a fish egg to an underyearling stage will become a starting point in the investigation of the environmental influence on to the new herring generations.

Assessment of reproductive capacity of representatives of ancestral complexes and especially their selection of seed in dry conditions

2019 ◽  
pp. 1-23
Author(s):  
А.В. Семенютина ◽  
С.Е. Лазарев ◽  
К.А. Мельник
Keyword(s):  
Weather Conditions ◽  
Reproductive Capacity ◽  
Limiting Factors ◽  
Scientific Center ◽  
Gleditsia Triacanthos ◽  
Biological Potential ◽  
Forest Reclamation ◽  
Dry Conditions ◽  
Generative Phase ◽  
Selection Of

Представители родовых комплексов Robinia (Робиния), Gleditsia (Гледичия) относятся к экономически важным и перспективным, для деградированных ландшафтов засушливого региона, видам растений. Несмотря на это до последнего времени отсутствуют сведения по многим видам этих родовых комплексов, связанные с вопросами экологических основ семеноведения и их репродуктивной способности в условиях светлокаштановых почв Волгоградской области. Все это направлено на выявление и расширение перспективных ареалов культивирования для лесомелиорации и озеленения населенных пунктов. Цель исследований изучение репродуктивной способности представителей родовых комплексов Robinia (Робиния), Gleditsia (Гледичия) в коллекциях ФНЦ агроэкологии РАН и выявление особенностей их селекционного семеноведения для лесомелиорации и озеленения населенных пунктов в сухостепных условиях. Объектами исследований являлись виды и формы рода Robinia: R. viscosa Vent. R. neomexicana Gray. R. pseudoacacia L. R. neomexicana х pseudoacacia, и Gleditsia (G. triacanthos L., G. triacanthos L. f. inermis, G. caspica Desf, G. texana Sarg., G. aquatica, G. japonica, G. caspica, G. sinensis), произрастающие в кластерных участках коллекций ФНЦ агроэкологии РАН, кадастр 34:34:000000:122, 34:34:060061:10. Разработка основ селекционного семеноведения базируется на изучении репродуктивных особенностей выделенных для целевого использования собственных биоресурсов с учетом возможностей всестороннего изучения генеративных качеств и оценки биологического потенциала. Выявлено, что стабильность плодоношения фиксируется через несколько лет после вступления в генеративную фазу: у Robinia и Gleditsia 67 лет. Первое цветение у Gleditsia triacanthos и G. texana, G. aquatica наблюдалось в возрасте 5 лет, G. japonica 6, G. caspica и G. sinensis 8 лет. Завязываемость плодов зависит не только от возраста растения, но и от погодных условий во время цветения. На семенную продуктивность влияет количество выпавших осадков и сумма активных температур в период созревания плодов. Формирование более крупных плодов и семян наблюдается в возрасте до 15 лет. В результате исследований (20172019 гг.) выявлено влияние лимитирующих факторов на биологический потенциал цветения, плодоношения и семенную продуктивность для определения ареалов их культивирования. Representatives of generic systems Robinia, Gleditsia are economically important and promising for degraded arid landscapes of the region, types of plants. Despite this, until recently, there is no information on many types of these generic complexes related to the environmental foundations of seed and their reproductive capacity in light chestnut soils of the Volgograd region. All this is aimed at identifying and expanding promising areas of cultivation for forest reclamation and greening of settlements. The aim of the research is to study the reproductive capacity of representatives of ancestral complexes Robinia, Gleditsia in the collections of the Federal scientific center for Agroecology Russian Academy of Sciences and the identifying features of their selection of seed for forest reclamation and landscaping of settlements in the dry steppe conditions. The objects of research were species and forms of the genus Robinia: R. viscosa Vent. R. neomexicana Gray. R. pseudoacacia L. R. neomexicana x pseudoacacia and Gleditsia (G. triacanthos L., G. triacanthos L. f. inermis, G. caspica Desf, G. texana Sarg., G. aquatica, G. japonica, G. caspica, G. sinensis), growing in the cluster areas of collections of FSC Agroecology RAS, cadastre 34:34:000000:122, 34:34:060061:10. The development of the principles of seed breeding is based on the study of reproductive characteristics of the allocated for the targeted use of their own bioresources, taking into account the possibilities of a comprehensive study of generative qualities and assessment of biological potential. It was found that the stability of fruiting is fixed a few years after entering the generative phase: Robinia and Gleditsia 67 years. The first flowering in Gleditsia triacanthos and G. texana, G. aquatica was observed at the age of 5 years, G. japonica 6, G. caspica and G. sinensis 8 years. Fruit setability depends not only on the age of the plant, but also on weather conditions during flowering. Seed productivity is affected by the amount of precipitation and the amount of active temperatures during the ripening period. The formation of larger fruits and seeds is observed in the age of 15 years. As a result of studies (20172019), the influence of limiting factors on the biological potential of flowering, fruiting and seed production to determine the areas of their cultivation was revealed.

New M40Ar/39Ar and K/Ar Ages of Dikes in the South Shetland Islands (Antarctic Peninsula)

2007 ◽  
Author(s):  
S. Kraus ◽  
M. McWilliams ◽  
Z. Pecskay
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Islands ◽  
The South ◽  
Shetland Islands

The Benefits of Biotreatment for Reducing the Effects of Pulp and Paper Mill Effluents on Fish Reproduction in Laboratory Tests

2008 ◽  
Vol 43 (2-3) ◽  
pp. 161-171 ◽  
Author(s):  
Pierre Martel ◽  
Tibor Kovacs ◽  
Virginie Bérubé
Keyword(s):  
Laboratory Tests ◽  
Egg Production ◽  
Pimephales Promelas ◽  
Paper Mill ◽  
Pulp And Paper ◽  
Reproductive Capacity ◽  
Fish Reproduction ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Gonad Size

Abstract Pulp and paper mill effluents have been reported to cause changes in reproductive indicators of fish in laboratory and field studies. These changes include reduced egg production and gonad size, and altered hormone levels and expression of secondary sex characteristics. We examined the performance of biotreatment plants for their potential in abating effects of pulp and paper mill effluents on fish reproduction under laboratory conditions. A bleached kraft mill effluent (BKME) treated in an aerated lagoon and a thermomechanical pulp mill effluent (TMPE) treated by aerobic sludge in a sequential batch reactor were selected for study. Mature fathead minnows (Pimephales promelas) were exposed to effluents before and after biotreatment under continuous renewal conditions for 21 days. Egg production was monitored daily, while morphometric parameters (length, weight, gonad size), secondary sexual characteristics, and steroid hormone and vitellogenin levels were measured at the end of the effluent exposure. The effluent from both mills before biotreatment impaired the reproductive capacity of minnows (egg production) at concentrations of 10 and 20% vol/vol, but not at 2% vol/vol. Exposure to biotreated effluents from both mills at concentrations of 2, 10, 20, and 40% vol/vol caused no significant differences in overall reproductive capacity of minnows as compared with controls. These results indicate that biotreatment can significantly improve the quality of a BKME and an effluent from a TMP mill with respect to the reproductive capacity of fish as determined in laboratory tests.

Effect of Oil on Reproductive Capacity of Callianassa kraussi

1982 ◽  
Vol 14 (9-11) ◽  
pp. 1573-1573
Author(s):  
Lynn F Jackson
Keyword(s):  
Reproductive Capacity
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