Embryonic Development and Energetic Investment in Egg Production in Relation to Size of Female Lobster (Homarus americanus)

1987 ◽  
Vol 44 (6) ◽  
pp. 1157-1164 ◽  
Author(s):  
Jean Attard ◽  
Christiane Hudon
Keyword(s):  
Embryonic Development ◽  
Egg Production ◽  
Energy Content ◽  
Larval Growth ◽  
Somatic Growth ◽  
Dry Weight ◽  
Homarus Americanus ◽  
Female Size ◽  
Growth And Survival ◽  
The Difference

The egg development index, dry weight, and energy content were measured on eggs from 148 ovigerous female lobsters (Homarus americanus) caught off îles de la Madeleine (Québec). Two modes of embryonic development were observed at stages 3 and 8 (Perkins. 1972. Fish. Bull. 70: 95–99). Stage 3 predominated among females of 71–82 mm and stage 8 among those of 83–110 mm carapace length (CL), indicating that larger females both extrude and hatch their eggs earlier than smaller females. Energy content per egg increased with female size and ranged from 4.6 cal∙egg−1 for females 72–76 mm CL to 5.2 cal∙egg−1 for females 107–110 mm CL. Females between 82 and 90 mm CL invested 0.155 kcal per gram of their own weight in egg production, which was the maximum value in the size range. Females smaller than 82 mm CL and larger than 90 mm CL expended proportionately less on egg production, with the difference allocated to either somatic growth in the smaller or maintenance in the larger animals. Large females produce proportionately more eggs, containing more calories per egg which hatch at an earlier time than small females. The higher energy content of eggs from large females and their earlier hatching are probably factors that enhance larval growth and survival. If so, large females contribute relatively more to recruitment than their greater fecundity.

scholarly journals Evolution of reduced pre-adult viability and larval growth rate in laboratory populations of Drosophila melanogaster selected for shorter development time

2000 ◽  
Vol 76 (3) ◽  
pp. 249-259 ◽  
Author(s):  
N. G. PRASAD ◽  
MALLIKARJUN SHAKARAD ◽  
VISHAL M. GOHIL ◽  
V. SHEEBA ◽  
M. RAJAMANI ◽  
...  
Keyword(s):  
Growth Rate ◽  
Drosophila Melanogaster ◽  
Development Time ◽  
Larval Growth ◽  
Dry Weight ◽  
Relative Reduction ◽  
Larval Growth Rate ◽  
Laboratory Populations ◽  
The Difference ◽  
Faster Development

Four large (n > 1000) populations of Drosophila melanogaster, derived from control populations maintained on a 3 week discrete generation cycle, were subjected to selection for fast development and early reproduction. Egg to eclosion survivorship and development time and dry weight at eclosion were monitored every 10 generations. Over 70 generations of selection, development time in the selected populations decreased by approximately 36 h relative to controls, a 20% decline. The difference in male and female development time was also reduced in the selected populations. Flies from the selected populations were increasingly lighter at eclosion than controls, with the reduction in dry weight at eclosion over 70 generations of selection being approximately 45% in males and 39% in females. Larval growth rate (dry weight at eclosion/development time) was also reduced in the selected lines over 70 generations, relative to controls, by approximately 32% in males and 24% in females. However, part of this relative reduction was due to an increase in growth rate of the controls populations, presumably an expression of adaptation to conditions in our laboratory. After 50 generations of selection had elapsed, a considerable and increasing pre- adult viability cost to faster development became apparent, with viability in the selected populations being about 22% less than that of controls at generation 70 of selection.

Changes in female lobster (Homarus americanus) size at maturity and implications for the lobster resource in Long Island Sound, Connecticut

2001 ◽  
Vol 52 (8) ◽  
pp. 1283 ◽  
Author(s):  
Donald F. Landers Jr ◽  
Milan Keser ◽  
Saul B. Saila
Keyword(s):  
Sexual Maturity ◽  
Egg Production ◽  
Long Island ◽  
Homarus Americanus ◽  
Long Island Sound ◽  
Female Size ◽  
Size At Maturity ◽  
Size At Sexual Maturity ◽  
Average Size ◽  
Island Sound

Population theory predicts that, under conditions of high age/size-specific mortality rates, individuals in highly exploited populations increase their fitness by decreasing size at sexual maturity, relative to less exploited populations. The benefit of early reproductive maturation is that individuals have a higher probability of surviving to maturity and contributing progeny to maintain the population. Empirical evidence, based on morphometric data from nearly 60 000 female lobsters collected since 1981, suggests that size at sexual maturity of female lobsters in Long Island Sound (USA) has recently decreased. Our findings were supported by decreases in average size and increases in abundance of egg-bearing females over the past two decades. Changes in female size at maturity and subsequent higher egg production may also help to explain the recent increase in lobster recruitment and landings. It is unclear whether these changes were caused by density-dependent factors related to the high exploitation of the species, by natural environmental factors (e.g. higher seawater temperatures), or a combination of the two.

Differences in biological characteristics of two strains of the cestode Hymenolepis diminuta

Parasitology ◽  
1987 ◽  
Vol 95 (1) ◽  
pp. 97-110 ◽  
Author(s):  
H. Kino ◽  
C. R. Kennedy
Keyword(s):  
Egg Production ◽  
Genetic Basis ◽  
Strain Difference ◽  
Rattus Rattus ◽  
Dry Weight ◽  
Biological Characteristics ◽  
Hymenolepis Diminuta ◽  
Multiple Infections ◽  
The Mean ◽  
The Difference

SUMMARYBiological characteristics of infectivity, growth rate and fecundity of Hymenolepis diminuta isolated from wild Rattus rattus in Japan were compared with parasites of Texas origin maintained for several generations in this and many other laboratories in laboratory bred Rattus norvegicus. The timing of development and maturation was similar in parasites from both sources, but the mean parasite dry weight was less and the mean egg production lower in Japanese parasites in both single and multiple infections. The differences persisted over 10 weeks in single infections, and were unaffected by rat strain. In all experiments there was much greater variation and heterogeneity in the biological characteristics of the Japanese parasites. It was concluded that the Texas parasites were better adapted to R. norvegicus and in the course of adaptation had become more homogeneous, and that the difference between the parasite strains had a complex genetic basis. Some Japanese parasites of the early isolated generations failed to produce normal eggs, but the proportion of these decreased in later generations. However, selected individual Japanese parasites whose egg production was equal to that of parasites of Texas origin did not produce offspring of larger mean size or higher mean fecundity, and heterogeneity of these characteristics was maintained. In the intermediate host, the mean number of cysticercoids of the Japanese isolate per beetle was higher than that of the Texas strain in Tribolium confusum but lower in Tenebrio molitor. The greater heterogeneity exhibited by Japanese parasites and the genetic basis of the strain difference are discussed with particular reference to geographical isolation, differences in definitive hosts and co-evolution of wild and laboratory host and parasite populations.

Female American lobster (Homarus americanus) size-at-maturity declined in Canada during the 20th and early 21st centuries

2018 ◽  
Vol 75 (6) ◽  
pp. 908-924 ◽  
Author(s):  
Marthe Larsen Haarr ◽  
Bernard Sainte-Marie ◽  
Michel Comeau ◽  
M. John Tremblay ◽  
Rémy Rochette
Keyword(s):  
Egg Production ◽  
Homarus Americanus ◽  
American Lobster ◽  
Past Century ◽  
Female Size ◽  
Strongly Correlated ◽  
Size At Maturity ◽  
The Past ◽  
Evolutionary Response ◽  
Intense Exploitation

Changes in the environment and fishing have been shown to affect life-history characteristics, such as size or age of maturation, in a number of finfish and invertebrates. The American lobster (Homarus americanus) supports Canada’s most valuable fishery and exploitation rates are high. Female size-at-maturity (SM) is an important parameter in management of this species, as it is used in establishing minimum legal size regulations. In this study, we show with historical and recent data that SM of female American lobsters has declined across most of Canada, in some areas by as much as 30%, over the past 10–80 years. The spatial patterns of these declines are inconsistent with patterns of rising ocean temperature and lobster abundance (density). They are, however, strongly correlated to the strength of size-based fishery selection, and egg-per-recruit modeling indicates a gain in lifetime egg production associated with observed SM declines under a range of realistic harvesting scenarios. These findings suggest that the marked decrease we document in SM of female American lobsters in Canada over the past century represents an evolutionary response to intense exploitation.

scholarly journals PSVIII-15 Polymorhpism of dysferlin gene in chickens

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 272-272
Author(s):  
Anna Krutikova ◽  
Kirill Plemyashov ◽  
Natalia Dementeva
Keyword(s):  
Body Weight ◽  
Embryonic Development ◽  
Egg Production ◽  
Myoblast Fusion ◽  
Egg Laying ◽  
Muscle Membrane ◽  
Reference Period ◽  
Egg Weight ◽  
Negative Effect ◽  
The Difference

Abstract Dysferlin is associated with the formation of the muscle membrane, is involved in the repair of the muscle membrane and the regulation of myoblast fusion. In humans, mutations in the dysferlin gene lead to various types of muscle pathologies. The effect of dysferlin on the formation of muscle structures was detected in the early stages of embryonic development. We have suggested that mutations in the dysferlin gene in chickens can have a negative effect on the formation of muscle mass and meat traits of chickens. SNP rs16455118 was studied on chickens of different breeds and hybrids of broilers and layers. Body weight was controlled in 7, 49 and 330 days. Layers were used as a contrast. Standard indicators of egg traits (age of the first egg laying, egg production for 6 months, egg weight) were studied. SNP rs16455118 leads to the replacement of adenine by cytosine in the intron of the dysferlin gene. The GWAS method was used. As a result, the association of SNP in the dysferlin gene with meat traits in chickens was not found. But a statistically significant association of certain genotypes with egg trait in Russian white chickens was determined. Chickens with the AA and AC genotypes had more eggs compared to their peers with the SS genotype during the reference period. The difference was 10 eggs an average of (P ≤ 0.05). Project number: AAAA-A18-118021590138-1

Local egg production and larval losses to advection contribute to interannual and long-term variability of American lobster (Homarus americanus) settlement intensity

2019 ◽  
Vol 76 (3) ◽  
pp. 350-363
Author(s):  
Louise Gendron ◽  
Denis Lefaivre ◽  
Bernard Sainte-Marie
Keyword(s):  
Ocean Circulation ◽  
Egg Production ◽  
Size Structure ◽  
Growth Models ◽  
Larval Growth ◽  
Circulation Model ◽  
Homarus Americanus ◽  
American Lobster ◽  
Positive Trend

American lobster (Homarus americanus) egg production and settlement intensity were examined over a 19-year period (1995–2013) in the Gulf of St. Lawrence at the Magdalen Islands (MI), where the population is spatially isolated during the benthic phase. Settlement and hatch dates by year were back-calculated from observed young-of-the-year size structure and juvenile and larval growth models. Drift of locally released larvae, from stage I to the end of stage III, was simulated using an ocean circulation model. Settlement intensity was related positively to egg production and negatively to drift distance. There was a strong positive trend in settlement intensity explained largely by increasing egg production, as well as by declining larval duration and drift distance. In the last years of the study, settlement intensity may have been limited by nursery saturation. The results suggest that demographic connectivity through larval drift is highly dynamic in time and that it declined during our study period. The demographic dependence of the MI lobster population on other populations in the Gulf of St. Lawrence is probably low.

Cholesterol Requirements of Juvenile American Lobster (Homarus americanus)

1975 ◽  
Vol 32 (8) ◽  
pp. 1431-1435 ◽  
Author(s):  
John D. Castell ◽  
Edgar G. Mason ◽  
Jane F. Covey
Keyword(s):  
Brine Shrimp ◽  
Control Diet ◽  
Dietary Cholesterol ◽  
Dry Weight ◽  
Homarus Americanus ◽  
American Lobster ◽  
Cod Liver Oil ◽  
Mineral Salts ◽  
Growth And Survival ◽  
Feeding Trials

In preliminary feeding trials with juvenile American lobsters (Homarus americanus) there were some differences in growth and survival that appeared to be related to deletion or addition of cod liver oil, mineral salts, vitamins, and glucosamine. However, the results were questionable due to deficiency of dietary cholesterol. Only when 1% cholesterol was added to the control diet was growth and survival achieved similar to that of lobsters fed brine shrimp. The optimum or required level of cholesterol was found to be approximately 0.5% of the dry weight of the diet.

Declining fecundity and factors affecting embryo quality in the American lobster (Homarus americanus) from the Bay of Fundy

2015 ◽  
Vol 72 (3) ◽  
pp. 352-363 ◽  
Author(s):  
Heather N. Koopman ◽  
Andrew J. Westgate ◽  
Zachary A. Siders
Keyword(s):  
Embryo Quality ◽  
Gulf Of Maine ◽  
Energy Content ◽  
Homarus Americanus ◽  
Striking Difference ◽  
Bay Of Fundy ◽  
American Lobster ◽  
Female Size ◽  
Factors Affecting ◽  
Old Females

Recent perturbations in ecosystem and environmental dynamics in the habitat of the American lobster have led to increases in abundance, with unprecedented high landings in some regions. Despite the commercial value of this species, surprisingly little is known about maternal and environmental influences on its reproductive output. We measured fecundity and embryo quality in 1370 ovigerous lobsters from the Bay of Fundy, Canada, during 2008–2013. Female size was generally positively correlated with fecundity (P < 0.001), although some of the very large (and presumably old) females brooded significantly fewer eggs than expected. Egg energy content and lipid content and composition exhibited significant annual differences, indicating environmentally based variation. The most striking difference was a 31% decline in fecundity from 2008 to 2013 (8%–10% per year). We hypothesize that recent warming trends could be responsible for reduced fecundity. Decreased fecundity may be a cause for concern for future recruitment in this population, which has been shown to be an important source of larvae for the Gulf of Maine metapopulation.

Planktonic Growth of Larval Lobster (Homarus americanus) off îles de la Madeleine (Quebec), Gulf of St. Lawrence

1988 ◽  
Vol 45 (5) ◽  
pp. 868-878 ◽  
Author(s):  
Christiane Hudon ◽  
Pierre Fradette
Keyword(s):  
Growth Rates ◽  
Atlantic Coast ◽  
Larval Growth ◽  
Homarus Americanus ◽  
Stage I ◽  
Female Size ◽  
Larval Size ◽  
Size Frequency Distribution ◽  
Geographical Variations ◽  
La Madeleine

The carapace length of the three planktonic larval and one postlarval stages of Homarus americanus was measured for larvae collected off îles de la Madeleine over three summers. Mean larval size did not vary between years or locations around the islands. The size of stages I and II remained constant throughout the summer, but after molting into stages III and IV, larvae diminished in size through the summer. Size frequency distribution became more scattered as larvae grew into more advanced stages. The increase of variance with size between stages I–IV followed the same progression as that observed between stages V–XIII, allowing prediction of the variance associated with mean size at each stage. The size of stage I larvae collected in nine regions along the Atlantic coast was not correlated with the July surface water temperature or with the smallest female size at maturity. Comparison of various body proportions suggested that a single morphometric measurement is not sufficient to describe geographical variations in size. Percentage growth per molt decreased with each successive molt. During summer, increment at molt decreased and molt frequency increased. Larval growth rates followed closely the temperature regime, with maximum growth rate attained during the warmest period of the summer (July 30 – August 9). The duration of the first three larval stages estimated from field data was of 24 d compared with 21 d calculated from previous laboratory studies. The maximum abundance of stage I larvae was synchronized with the period of most rapid increase in summer temperature, thus insuring that larvae achieved highest net growth rates through their planktonic phase.

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