The embryonic development of the black prickleback, Xiphister atropurpureus, a Pacific Coast blennioid fish

1974 ◽  
Vol 52 (7) ◽  
pp. 879-887 ◽  
Author(s):  
John P. Wourm ◽  
David Evans
Keyword(s):  
Positive Reinforcement ◽  
General Pattern ◽  
Larval Growth ◽  
Behavioral Pattern ◽  
Egg Mass ◽  
High Survival ◽  
Egg Survival ◽  
Organ Differentiation ◽  
Probability Of Survival ◽  
Xiphister Atropurpureus

Spawning of Xiphister atropurpureus occurs during late April–May. Eggs are deposited in a coherent mass which is guarded by the parents. Development is divided into 35 stages. At 13 °C, eggs require 21 days to hatch. Stage 1 is an unfertilized ovum. Cleavage during stages 2–11 produces a typical teleost blastula. During epiboly, which begins at stage 12 and ends at stage 14, the embryonic axis is formed. Stages 15 to 31 are periods of embryonic growth and organ differentiation. Hatching occurs at stage 32. Larval growth occurs during stages 33–35. Yolk absorption is complete 10 days post hatching. The general pattern of development is similar to that of most teleosts. The newly hatched larva, although large, retains many embryonic characteristics. The eel-like shape of the adult is mirrored in the long body of the larva. Larval morphology and the life history of allied forms suggest a pelagic existence for Xiphister larvae. The behavioral pattern of egg aggregation during Xiphister spawning is considered to have a high survival value. (1) It reduces the probability of predation on single eggs and increases the probability of egg survival. (2) The inability of a predator to obtain positive reinforcement from finding single dispersed eggs may lead to abandonment of localized predator search patterns. (3) Since the egg mass is subject to a larger size, but numerically smaller predator class, the probability of egg-mass survival is increased. (4) As the unit of predation shifts from an egg to the egg mass, survival remains on an individual basis. Since the probability of predation is equally shared, the probability of survival appears to be increased by a factor proportional to total egg number (about 500). Parental care also enhances egg survival.

The annual reproductive cycle of the black prickleback, Xiphister atropurpureus, a Pacific Coast blennioid fish

1974 ◽  
Vol 52 (7) ◽  
pp. 795-802 ◽  
Author(s):  
John P. Wourms ◽  
David Evans
Keyword(s):  
Reproductive Cycle ◽  
Egg Size ◽  
Gonad Index ◽  
Egg Mass ◽  
Base Line ◽  
Annual Reproductive Cycle ◽  
Intertidal Habitat ◽  
Spawning Period ◽  
Egg Number ◽  
Xiphister Atropurpureus

Semimonthly determinations of the gonad index made during the course of a year show that Xiphister atropurpureus has an annual reproductive cycle. The gonad index (ovary) increases during midwinter, attains a maximum value of 20 in late April–May, and declines to a base-line value of 0.5 from June to December. Spawning occurs during a 6-week period in late April–May. Spawning takes place in zone 4 of the intertidal habitat. Eggs deposited singly are fertilized and then shaped into a spherical mass by the parents. As egg envelopes harden, they adhere to one another to form a coherent mass. The egg mass is guarded by one or both parents. The annual reproductive cycle is considered to be a necessary consequence of the energetic demands of oogenesis combined with selection for a spawning period which is environmentally optimal. Alternative cycles based on modification of the present egg size (large)/egg number (few) relationship do not appear feasible, since the required modification of the egg size/egg number ratio would be selectively disadvantageous. The intertidal habitat of Xiphisier is subject to several potential environmental hazards: wave shock, reduced salinity due to rain and runoff, and excessively high or low temperatures. These are seasonal hazards which occur during winter or summer. Spawning is timed (April–May), so the probability that developing eggs will be exposed to environmental risks is minimized while the probability of exposure to environmental benefits is maximized. It is suggested that the reproductive cycle is under photoperiodic control.

scholarly journals Effects of elevated CO2 levels on eggs and larvae of a North Pacific flatfish

2015 ◽  
Vol 73 (3) ◽  
pp. 981-990 ◽  
Author(s):  
Thomas P. Hurst ◽  
Benjamin J. Laurel ◽  
Jeremy T. Mathis ◽  
Lauren R. Tobosa
Keyword(s):  
Ocean Acidification ◽  
Elevated Co2 ◽  
Larval Growth ◽  
Gulf Of Alaska ◽  
Growth Responses ◽  
Egg Survival ◽  
Co2 Levels ◽  
Co2 Level ◽  
The One ◽  
Eggs And Larvae

Abstract The Bering Sea and Gulf of Alaska support a number of commercially important flatfish fisheries. These high latitude ecosystems are predicted to be most immediately impacted by ongoing ocean acidification, but the range of responses by commercial fishery species has yet to be fully explored. In this study, we examined the growth responses of northern rock sole (Lepidopsetta polyxystra) eggs and larvae across a range of CO2 levels (ambient to 1500 µatm) to evaluate the potential sensitivity to ocean acidification. Laboratory-spawned eggs and larvae were reared at 8°C in a flow-through culture system in which CO2 levels were maintained via computer-controlled injection of CO2 into a seawater conditioning tank. Overall, we observed only minor effects of elevated CO2 level on sizes of northern rock sole larvae. Size at hatch differed among offspring from four different females, but there was no significant effect of CO2 level on egg survival or size at hatch. In three separate larval growth trials, there was little effect of CO2 level on growth rates through the first 28 d post-hatch (DPH). However, in the one trial extended to 60 DPH, fish reared at the highest CO2 level had lower condition factors after 28 DPH, suggesting that larvae undergoing metamorphosis may be more sensitive to environmental hypercapnia than earlier pre-flexion stages. These results suggest that while early life stages of northern rock sole are less sensitive to ocean acidification than previously examined flatfish, they may be more sensitive to elevated CO2 levels than a previously studied gadid with a similar geographic range.

Neonatal survival: an overview

1992 ◽  
Vol 15 ◽  
pp. 1-7 ◽  
Author(s):  
M. A. Varley
Keyword(s):  
Medical Profession ◽  
Survival Rates ◽  
Farm Animals ◽  
Physical Factors ◽  
High Survival ◽  
Animal Agriculture ◽  
Factors Affecting ◽  
Neonatal Deaths ◽  
Probability Of Survival ◽  
Use Of Resources

AbstractMortality in neonates has always represented significant economic wastage and slow progress has been made in the understanding of the factors influencing the probability of survival or death. There is also increasing pressure in the animal agriculture sphere to pursue improved welfare and in the situation where neonatal deaths are a high proportion of the liveborn offspring, then this becomes not only an economic concern but also a welfare issue. This paper highlights principal problems within the neonatal area in order to introduce the ensuing text dealing with specific technical challenges.The magnitude of loss for different species including humans is given and the factors affecting mortalities are discussed. The major components include: human factors, pathogenic agents, immunological factors, temperature and thermoregulation, nutrition, behaviour and physical factors.Although single factors are often ascribed as the cause of death, the reality is that there are usually multifactorial components involved which interact and contribute to the final mortality of the individual.The approach to the practical management of neonates varies widely between the different animal industries and the techniques deployed depend on relative economic values. In human health care every available resource is used to ensure very high survival rates because of the incalculable value of each individual delivered. With farm animals the use of resources is at a much lower level and survival rates are lower. It ought to be possible in animal agriculture to adopt some of the methods used in the medical profession to assess high risk situations and to divert resources appropriately.

Does the fall phytoplankton bloom control recruitment of Georges Bank haddock, Melanogrammus aeglefinus, through parental condition?

2008 ◽  
Vol 65 (6) ◽  
pp. 1076-1086 ◽  
Author(s):  
Kevin D. Friedland ◽  
Jonathan A. Hare ◽  
Grayson B. Wood ◽  
Laurel A. Col ◽  
Lawrence J. Buckley ◽  
...  
Keyword(s):  
Phytoplankton Bloom ◽  
Larval Growth ◽  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Growth And Survival ◽  
Probability Of Survival ◽  
Bank Stock ◽  
Parental Condition ◽  
Recruitment Event ◽  
Haddock Melanogrammus Aeglefinus

In 2003, the Georges Bank stock of haddock ( Melanogrammus aeglefinus ) experienced the largest recruitment event recorded during its assessed history. Several hypotheses have been advanced to explain recruitment variability in this much-scrutinized stock, including variability in the retention of eggs and larvae on Georges Bank, the timing of haddock spawning, and variability in the spring bloom, which influences larval growth and survival. Although these processes may contribute to the formation of successful year classes, none of the factors associated with these previous hypotheses provides an adequate explanation of the 2003 recruitment event. We analyzed data on the dynamics of the fall phytoplankton bloom the year prior to spawning and show it to be highly correlated with subsequent recruitment. We suggest that the fall bloom affects recruitment through enhanced condition of adults and by increasing the quantity and quality of their reproductive output, which in turn leads to a higher probability of survival of their offspring. Although synoptic data on the fall bloom are limited and our analyses are correlative, our purpose is to stimulate a rigorous test of this promising “parental condition hypothesis”.

Postembryonic growth and development of Caridina nilotica aruensis Roux (Decapoda: Atyidae) reared in the laboratory

1976 ◽  
Vol 27 (2) ◽  
pp. 263 ◽  
Author(s):  
JP Glaister
Keyword(s):  
Growth Rate ◽  
Growth And Development ◽  
Egg Size ◽  
Larval Growth ◽  
Egg Mass ◽  
Larval Life ◽  
Freshwater Shrimps ◽  
The Mean ◽  
Standard Deviations

The larval growth and development of C. n. aruensis reared in the laboratory is described and illustrated. Four zoeal and one post-zoeal stages were found to occur with an approximate time between hatching and metamorphosis of 14 days. The mean egg size was 0.64 by 0.40 mm with standard deviations of 0.042 and 0.028 respectively, whilst the mean number of eggs per egg mass was 74 (s.d. 15.2). The large egg size of C. n. aruensis is correlated with an abbreviated larval life and is a feature of many freshwater shrimps. Zoeal locomotion was thoracic whilst that of the post-zoea was abdominal. The growth rate of C. n. aruensis is described.

The effects of high rearing density on the potential for domestication selection in hatchery culture of steelhead (Oncorhynchus mykiss)

2015 ◽  
Vol 72 (12) ◽  
pp. 1829-1834 ◽  
Author(s):  
Neil F. Thompson ◽  
Michael S. Blouin
Keyword(s):  
Oncorhynchus Mykiss ◽  
Fork Length ◽  
High Density ◽  
High Survival ◽  
Environment Interaction ◽  
Family Selection ◽  
Probability Of Survival ◽  
Reduced Body ◽  
Domestication Selection ◽  
In The Wild

Hatchery-reared steelhead (Oncorhynchus mykiss) often have lower fitness than natural-origin fish when spawning in the wild. Fitness loss in hatcheries is partly due to genetic adaptation to captivity (domestication), but the underlying selection pressures driving adaptation remain unknown. Circumstantial evidence suggests that adaptation to hatcheries is accelerated when fish are reared at high density. We hypothesized two mechanisms by which high rearing densities could accelerate adaptation to the hatchery. First, high density could increase the among-family component of variation in fork length, which could increase the opportunity for selection after release. Second, a growth trade-off in fork length among families could occur across densities (family-by-environment interaction). We raised the same set of families, in replicate, at each of two densities. We found main effects of density (high density reduced body size) and family (accounted for 33%–53% of variance in size at release) on juvenile fork length. However, high density did not increase the percentage of variance in fork length among families, and there was weak evidence for a family-by-environment interaction. We propose an alternate model of how increased density might exacerbate domestication selection. The relationship between size at release and probability of survival is strongly nonlinear (almost truncational) for steelhead. Because high density decreases the fork lengths of all families approximately equally, high density could simply reduce the number of families that are above a threshold for high survival, resulting in strong among-family selection after release from the hatchery.

Physiology of tsetse flies (Glossina spp.) (Diptera: Glossinidae): a review

1977 ◽  
Vol 67 (4) ◽  
pp. 523-574 ◽  
Author(s):  
P. A. Langley
Keyword(s):  
General Pattern ◽  
Larval Growth ◽  
Malpighian Tubule ◽  
Accessory Gland ◽  
Tsetse Flies ◽  
Tsetse Control ◽  
Flight Metabolism ◽  
Gland Function ◽  
Major Review

AbstractSince no major review of the literature on tsetse physiology has hitherto been undertaken, relevant papers up to the beginning of 1977 are included in the present work. The physiology of Glossina is dealt with under three major headings; reproductive, developmental and nutritional events in the life of this haematophagous and viviparous insect are discussed in relation to general principles of insect physiology gained from the study of other genera. The role of adult maturation and the possible involvement of a sex pheromone in successful mating are considered. The difficulties of studying neuroendocrine function in relation to reproductive physiology in a viviparous insect, where reproductive and developmental events are not always separated chronologically, are emphasised. Nevertheless, the role of the neuroendocrine system in the control of such events as ovarian development, ovulation, parturition, pupariation and metamorphosis is considered, and the contribution that recent work on Glossina has made to an increased understanding of general principles in this field is discussed. Laboratory observations have demonstrated circadian components of behaviour in Glossina that can influence interpretation of field observations and likewise should influence the design of physiological experiments. Utilisation of nutritional reserves for larval growth and for flight activity has received considerable attention recently. The general pattern seems to be one of rapid mobilisation of blood-meal amino acids and the involvement of a large lipid reserve. The combined haematophagous and viviparous habit of Glossina has led to some interesting modifications of basic physiology particularly in regard to flight metabolism, female accessory gland function and Malpighian tubule activity. The relevance of physiological studies to current developments in the field of tsetse control is discussed and the importance of exploiting our knowledge in the quest for novel insecticidal techniques emphasised.

scholarly journals Frog vocalization is influenced by moon phases: Brazilian frogs tend to prefer low-albedo phases

Web Ecology ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 1-13
Author(s):  
Mauro S. C. S. Lima ◽  
Jonas Pederassi ◽  
Ulisses Caramaschi ◽  
Kléssia Denise S. S. Sousa ◽  
Carlos Alberto S. Souza
Keyword(s):  
Null Hypothesis ◽  
General Pattern ◽  
Lunar Cycle ◽  
Behavioral Pattern ◽  
Check Sample ◽  
Circadian Cycle ◽  
Moon Phases ◽  
Lunar Phases ◽  
The 1960S ◽  
Species Specific

Abstract. Lunar phases remarkably influence the circadian cycle of living beings. Early amphibian studies date back to the 1960s, but only recently has more research been conducted in this field. Much still needs to be understood to establish the behavioral pattern of this group according to the synodic cycle. In the present study, we sought to determine (i) whether the vocalization activity was influenced by the lunar phases and (ii) whether the influence was species-specific or affects the community with equal intensity. We expected a great diversity of behaviors and adaptations. Rayleigh's test was used to verify whether the sample differs significantly from the null hypothesis; Rao's test was used to check sample size sufficiency; and the Kiviat diagram was used to evaluate the activity of the species in relation to the complete synodic cycle. We have observed 1691 individuals of 37 species over 882 d. The lunar cycle influenced 78 % of the species, with 32 % preferring the lower-albedo phases. The activity pattern of each species was established. These results suggest that the lunar phases influence the vocalization activity of most species. Therefore, there is a general pattern of activity related to the synodic cycles; however, the specificities still need to be better understood.

scholarly journals Survival, Emigration, and Winter Population Structure of Harlequin Ducks

The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Fred Cooke ◽  
Gregory J. Robertson ◽  
Cyndi M. Smith ◽  
R. Ian Goudie ◽  
W. Sean Boyd
Keyword(s):  
Survival Rate ◽  
Population Differentiation ◽  
General Pattern ◽  
High Survival ◽  
Young Males ◽  
Young Females ◽  
Adult Females ◽  
Local Survival ◽  
Harlequin Ducks ◽  
Winter Population

AbstractA population of individually marked Harlequin Ducks (Histrionicus histrionicus) at White Rock, British Columbia, Canada was examined to measure the degree of population differentiation among birds which pair during the winter months. This required an understanding of the patterns of emigration among wintering sites in different segments of the population. Some juveniles arrived at the wintering grounds accompanied by their mothers, thus initially arriving into the same winter population as their parents. Young males were more likely than young females to disperse during the first two years of life. Adult males had higher local survival than adult females during the summer months, probably because of the greater mortality risks to nesting females. During the nonbreeding seasons, local survival was the same in both sexes. Paired males had a local survival of more than 90%, suggesting both high survival and strong philopatry. Unpaired males had a lower local survival rate, suggesting they have higher mortality and/or emigration rates. Young females had the same local survival rate as adult females, suggesting that they did not disperse during the winter. These winter philopatry patterns are similar to the general pattern of breeding philopatry in waterfowl, with females showing stronger philopatry than males, and paired adults stronger philopatry than unpaired and young birds. The dispersal of young males makes local population differentiation unlikely in this species.

scholarly journals Feeding and larval growth of an exotic freshwater prawn Macrobrachium equidens (Decapoda: Palaemonidae), from Northeastern Pará, Amazon Region

2014 ◽  
Vol 86 (3) ◽  
pp. 1525-1536 ◽  
Author(s):  
JEAN N. GOMES ◽  
FERNANDO A. ABRUNHOSA ◽  
ANNE K. COSTA ◽  
CRISTIANA R. MACIEL
Keyword(s):  
Survival Rate ◽  
Larval Development ◽  
Previous Experiment ◽  
Larval Growth ◽  
Juvenile Stage ◽  
Freshwater Prawn ◽  
High Survival ◽  
High Survival Rate ◽  
Feeding Experiment ◽  
Artemia Nauplii

In the present study, we carried out experiments on the diet of the freshwater prawn Macrobrachium equidens. We tested which type of food and which density of food is suitable for larval development. For the experiment on the type of food, eight treatments were carried out: (I) starvation, (AL) microalgae, (RO) rotifers, (AN) Artemia, (RO + AN) rotifers + Artemia, (AL + RO) microalgae + rotifers, (AL + AN) microalgae + Artemia, (AL + RO + AN) microalgae + rotifers + Artemia. For the experiment on the density of food, we used the type of food, which had resulted in a high survival rate in the previous experiment. Three treatments were carried out: 4, 8 and 16 Artemia nauplii /mL. The rate of feeding during larval development was observed. The survival, weight and percentage of juveniles of each feeding experiment were determined. We found that larvae are carnivores; however, they have requirements with respect to the type of food, because larvae completed their cycle from the zoeal to the juvenile stage only when Artemia nauplii were available. We also verified that the larvae feed mainly during the day-time, and are opportunistic with respect to the density of food offered.

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