scholarly journals Life-history of the South American darter, Characidium pterostictum (Crenuchidae): evidence for small scale spatial variation in a piedmont stream

2008 ◽  
Vol 6 (4) ◽  
pp. 591-598 ◽  
Author(s):  
Fernando Gertum Becker ◽  
Silene de Carvalho ◽  
Sandra Maria Hartz
Keyword(s):  
Life History ◽  
Spatial Variation ◽  
Life History Theory ◽  
Spatial Scales ◽  
Gonadosomatic Index ◽  
Sampling Site ◽  
Small Scale ◽  
Upstream Site ◽  
Trade Off ◽  
Disturbed Site

The present study compares the reproduction, condition and size of the small characiform fish, Characidium pterostictum, sampled at close sites differing in severity of flash flood effects. Data were obtained from seasonal samples in two sites situated 8 km apart in the same stream. In the upstream site, habitat is more severely affected by flash floods than in the downstream site, and this difference was hypothesized to produce differences in life history and individual reproduction trade-off patterns, as predicted by life-history theory. The results provided evidence for small-scale spatial variation in life-history and trade-off patterns within the studied population. At the most severely disturbed site, C. pterostictum displayed a trade-off pattern that favored reproductive life-span (e.g., larger size, higher and seasonally stable condition, larger mean size of mature females) over instantaneous reproductive output (lower gonadosomatic index), while the opposite pattern was observed in the less disturbed site. Because of the differences in disturbance effects between each sampling site, these results suggest that within-stream variability in the severity of hydrological disturbance can influence life-history patterns at small spatial scales. An implication of the results is that fish occupying areas that are hydrologically more variable within a stream are not necessarily at an energetic or reproductive disadvantage, but may be simply under environmental conditions that favor distinct patterns of energy allocation (or trade-offs) and population persistence, as predicted by life-history theory. Therefore, plasticity in life-history is expected to be common in stream fish populations that are widespread in a stream system with spatially variable or patchy habitat characteristics.

Spatiotemporal variation in maturation: a case study with American plaice (Hippoglossoides platessoides) on the Grand Bank off Newfoundland

2020 ◽  
Vol 77 (10) ◽  
pp. 1688-1699
Author(s):  
Nan Zheng ◽  
Matthew Robertson ◽  
Noel Cadigan ◽  
Fan Zhang ◽  
Joanne Morgan ◽  
...  
Keyword(s):  
Life History ◽  
Spatial Variation ◽  
Fisheries Management ◽  
Life History Traits ◽  
Spatial Scales ◽  
Management Strategies ◽  
Spatiotemporal Variation ◽  
Small Scale ◽  
Spatial And Temporal Scales ◽  
Hippoglossoides Platessoides

Fisheries management usually does not explicitly account for spatial variation in life history traits within populations. However, for some stocks this spatial variation may be substantial. We develop a spatiotemporal generalized linear model and fit the model to a long time series of maturation data for American plaice (Hippoglossoides platessoides) on the Grand Bank off Newfoundland and Labrador. The spatiotemporal correlation structure improves estimation of small-scale spatiotemporal variation in maturity across locations and times with limited or few samples. We test how American plaice maturity varies at three different spatial resolutions. We find improvements in model fit when decreasing spatial scales for higher spatial resolution due to high levels of spatial heterogeneity in American plaice maturity at age and size. Modeling variation in life history traits at the appropriate spatial and temporal scales is necessary for understanding population dynamics and developing appropriate fisheries management strategies.

Small-scale temporal and spatial variation in Atlantic cod (Gadus morhua) life history

2003 ◽  
Vol 60 (9) ◽  
pp. 1111-1121 ◽  
Author(s):  
Tara M McIntyre ◽  
Jeffrey A Hutchings
Keyword(s):  
Body Mass ◽  
Life Histories ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Scales ◽  
Gonadosomatic Index ◽  
Small Scale ◽  
Hepatosomatic Index ◽  
Georges Bank ◽  
High Fecundity

Life histories of Atlantic cod (Gadus morhua) from the Gulf of St. Lawrence south to Georges Bank differ significantly through time and space. Within the Southern Gulf, fecundity per unit body mass differed by more than 40% over short (2 years) and long (42–45 years) periods of time. Significant variation in size-specific fecundity is also evident among populations: Southern Gulf cod produce almost 30% more eggs per unit body mass than those on Georges Bank, whereas fecundity of Scotian Shelf cod is almost half that of cod in Sydney Bight. Compared with those on Georges Bank, Southern Gulf cod life histories are characterized by high fecundity, late maturity, high gonadosomatic index, and large eggs. Relative to the influence of body size, neither temporal nor spatial differences in fecundity can be attributed to physiological condition, as reflected by liver weight, hepatosomatic index, and Fulton's K. Delayed maturity and higher reproductive allotment among Southern Gulf cod can be explained as selection responses to slower growth, higher prereproductive mortality, and fewer lifetime reproductive events. Patterns of covariation in heritable, fitness-related traits suggest the existence of adaptive variation and evolutionarily significant units at spatial scales considerably smaller than the species range in the Northwest Atlantic.

scholarly journals Trade-off between offspring mass and number: the lightest offspring bear the costs

2020 ◽  
Vol 16 (2) ◽  
pp. 20190707
Author(s):  
Joanie Van de Walle ◽  
Andreas Zedrosser ◽  
Jon E. Swenson ◽  
Fanie Pelletier
Keyword(s):  
Life History ◽  
Litter Size ◽  
Phenotypic Variation ◽  
Reproductive Strategy ◽  
Life History Theory ◽  
Brown Bear ◽  
Offspring Size ◽  
Trade Off ◽  
The Relationship

Life-history theory predicts a trade-off between offspring size and number. However, the role of intra-litter phenotypic variation in shaping this trade-off is often disregarded. We compared the strength of the relationship between litter size and mass from the perspective of the lightest and the heaviest yearling offspring in 110 brown bear litters in Sweden. We showed that the mass of the lightest yearlings decreased with increasing litter size, but that the mass of the heaviest yearling remained stable, regardless of litter size. Consistent with a conservative reproductive strategy, our results suggest that mothers maintained a stable investment in a fraction of the litter, while transferring the costs of larger litter size to the remaining offspring. Ignoring intra-litter phenotypic variation may obscure our ability to detect a trade-off between offspring size and number.

scholarly journals Trade-off between age of first reproduction and survival in a female primate

2009 ◽  
Vol 5 (3) ◽  
pp. 339-342 ◽  
Author(s):  
Gregory E. Blomquist
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Rhesus Macaques ◽  
Human Study ◽  
Genetic Correlations ◽  
Adult Survival ◽  
Trade Off ◽  
Trade Offs ◽  
Female Life History ◽  
First Reproduction

Trade-offs are central to life-history theory but difficult to document. Patterns of phenotypic and genetic correlations in rhesus macaques, Macaca mulatta —a long-lived, slow-reproducing primate—are used to test for a trade-off between female age of first reproduction and adult survival. A strong positive genetic correlation indicates that female macaques suffer reduced adult survival when they mature relatively early and implies primate senescence can be explained, in part, by antagonistic pleiotropy. Contrasts with a similar human study implicate the extension of parental effects to later ages as a potential mechanism for circumventing female life-history trade-offs in human evolution.

scholarly journals Reproductive strategy of common dentex Dentex dentex: management implications

2016 ◽  
Vol 17 (2) ◽  
pp. 552 ◽  
Author(s):  
A. GRAU ◽  
F. SABORIDO-REY ◽  
E. PASTOR ◽  
M. PALMER ◽  
E. MASSUTÍ-PASCUAL ◽  
...  
Keyword(s):  
Sex Differences ◽  
Life History ◽  
Reproductive Strategy ◽  
Egg Production ◽  
Gonadosomatic Index ◽  
Life History Strategy ◽  
Minimum Size ◽  
Small Scale ◽  
Female Size ◽  
Dentex Dentex

Common dentex Dentex dentex is an iconic endangered species in the Mediterranean where is a sought after target species for small-scale, recreational and spearfishing fisheries. The reproductive biology of D. dentex in the natural environment is poorly known; therefore the reproductive strategy of the species was assessed by combining reproductive traits with the growth characteristics (estimated from length-at-age data), the size/age of sexual maturity and the energetic dynamics. A total of 358 wild fish were sampled on Mallorca Island (W Mediterranean) from March 1996 to June 1999 with a 19 to 84.7 cm total length (LT) range. The sex ratio was skewed towards females (1.361) albeit the length composition was not different between sexes (p = 0.551). Three young immature individuals (< 28 cm LT, 0.8% individuals) were rudimentary hermaphrodites supporting the late gonochoristic species classification. The age composition determined from sagitta otolith interpretation ranged from 0 to 26 years (yr). Concerning growth, between sex differences in von Bertalanffy parameters were not relevant, even after accounting for potential between-year differences. The most noticeable difference was found for L∞ (64.7 cm for females versus 61.6 for males) but even in this case, the bayesian credibility interval of between-sex differences included zero.  Maturity ogives at size and age showed that females achieved 50% maturity at 34.9 cm LT and 3.3 years, while males did at 33.8 cm LT and 2.5 years. The onset of gonad developing phase took place in December, while it progresses until April. The spawning peak was in April and May for both sexes. A generalized linear model showed that female size didn’t affect significantly the spawning season, whilst there was a strong seasonality in the spawning. Most of the evidences showed that fecundity is likely determinate, with an asynchronous oocyte development before spawning and a clear ovarian bimodal organization after the onset of spawning. Female weight explained 84% of the observed variance for fecundity. The gonadosomatic, hepatosomatic and condition indexes varied significantly with the reproductive season for females and only the gonadosomatic index for males. Storage in muscle seemed to be the primary source of energy for reproduction, although liver appeared to play a short-term role in egg production, suggesting a combination of capital and income breeding. The results indicate that the life history strategy of common dentex possess consist on maturing well before reaching maximum size, investing in growth after maturation, and therefore the reproductive effort is distributed through a longer lifespan and related with the size attained after maturation. At present no management measures are directed to D. dentex; given its life history strategy we suggest that a slot limit should be implemented, i.e. a minimum and a maximum landing size, with a minimum size of 35 cm. The upper threshold, to protect the higher reproductive potential of older and larger fish, should still be defined.

Less Food, Less Sex, Live Longer?

2012 ◽  
Author(s):  
Stephen J. Simpson ◽  
David Raubenheimer
Keyword(s):  
Life History ◽  
Life Span ◽  
Dietary Restriction ◽  
Life History Theory ◽  
Severe Malnutrition ◽  
Geometric Framework ◽  
Trade Off ◽  
Sexual Selection Theory ◽  
Males And Females ◽  
The Relationship

This chapter examines the relationships between nutrition, life span, and sex. It considers the view that dietary restriction without severe malnutrition prolongs life. It is generally believed that the benefits of dietary restriction arise from eating fewer calories. However, Geometric Framework experiments on insects in which the effects of macronutrients have been separated indicate that, rather than calories, a key determinant of the relationship between diet and longevity is the balance of protein to nonprotein (fat and/or carbohydrate) energy in the diet. Meanwhile, the presumption in much of life history theory that life span and reproduction trade off against each other for limiting resources is shown to be too simplistic. These two life-history variables certainly have differing nutritional optima, but they can be dissociated and do not inevitably trade off. Reproductive senescence and aging may proceed at different rates in males and females, as predicted by sexual selection theory.

scholarly journals Small-scale spatial variation in evolvability for life-history traits in the storm petrel

2012 ◽  
Vol 106 (2) ◽  
pp. 439-446 ◽  
Author(s):  
SIN-YEON KIM ◽  
ANA SANZ-AGUILAR ◽  
EDUARDO MÍNGUEZ ◽  
DANIEL ORO
Keyword(s):  
Life History ◽  
Spatial Variation ◽  
Life History Traits ◽  
Small Scale ◽  
Storm Petrel

scholarly journals Similar small-scale variation of diatom assemblages on different substrates in a mesotrophic stream

2015 ◽  
Vol 74 (2) ◽  
pp. 363-376 ◽  
Author(s):  
Maria Kahlert ◽  
Ivana Savatijević Rašić
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Spatial Variation ◽  
Anthropogenic Impacts ◽  
Sampling Site ◽  
Small Distance ◽  
Benthic Diatom ◽  
Small Scale ◽  
Diatom Species ◽  
Diatom Assemblages

Abstract The aim of the present study was to analyze if small-scale spatial variation of benthic diatom assemblages has consequences for biomonitoring. Benthic diatom samples were collected at one sampling site in a mesotrophic stream in Middle-Sweden from stone and plant (macrophytes and mosses) substrate. Our results showed that spatial variation of both the diatom species composition and the calculated bioindices were similar on both small (distance of centimeter) and medium (distance of decimeters) scales. Spatial variation was also similar on both studied substrates. This implies that it does not matter if a small or a larger area is sampled for biomonitoring as long as no major environmental factors impact certain sites systematically. Diatom assemblages and indices were significantly different between substrates. Spatial variation did not contribute much to this variation, and variation on a slide was unimportant. These results confirm earlier findings that smallscale spatial variation is not a problem when using diatoms to detect anthropogenic impacts to a stream or lake.

scholarly journals Temporal and spatial variation in size at maturity of the common whelk (Buccinum undatum)

2015 ◽  
Vol 72 (9) ◽  
pp. 2707-2719 ◽  
Author(s):  
Jodie A. Haig ◽  
Julia R. Pantin ◽  
Harriet Salomonsen ◽  
Lee G. Murray ◽  
Michel J. Kaiser
Keyword(s):  
Spatial Variation ◽  
Spatial Scales ◽  
Reproductive Activity ◽  
Small Scale ◽  
Driving Mechanism ◽  
Size At Maturity ◽  
Length Frequency ◽  
Buccinum Undatum ◽  
Combination Of Methods ◽  
Compare And Contrast

Abstract There is little common rationale for the 45 to 75 mm total shell length (TSL) minimum landing sizes (MLS) for Buccinum undatum among countries in the Northeast Atlantic. Size at maturity and length frequency of B. undatum populations vary over small spatial scales; however, the driving mechanism for this is unknown. Size at maturity research for B. undatum dates back to the late 1980s; since then, there has been little consensus on laboratory methods or in which season to undertake the research. Here, we assess small-scale spatial variation in size at maturity over a year to identify the seasons that increase error in visual maturity estimates. We compare and contrast results from methods used in the literature to estimate maturity for B. undatum. Monthly, B. undatum samples were obtained from Welsh fishers between May 2013 and May 2014 from eight sites at four locations (n = 5080). All whelks were sexed, weighed, and measured, and up to 60 whelks from each location were assessed for maturity (n = 1659). Mature whelks were found in all months, with a peak in reproductive activity through summer and early autumn, followed by the onset of spawning in November. Size at maturity varied between sexes and sites, and ranged from 51 to 76 mm TSL. Whelks caught in shallow waters (0–10 m) matured at a smaller size than those from deeper waters (up to 60 m). Length frequency varied at each site suggesting that a single increase in MLS would impact fishers disproportionately. No methodology trialled was found without inherent errors when used in isolation, though a combination of methods proved ideal. The seasonal variation in maturity estimates suggested that assigning maturity is increasingly difficult outside annual reproductive periods and that prespawning is the ideal time to undertake visual gonad assessments for whelks.

scholarly journals Life-History Implications of Large-Scale Spatial Variation in Adult Survival of Black Brant (Branta Bernicla Nigricans)

The Auk ◽  
2002 ◽  
Vol 119 (2) ◽  
pp. 510-515 ◽  
Author(s):  
James S. Sedinger ◽  
Nathan D. Chelgren ◽  
Mark S. Lindberg ◽  
Tim Obritchkewitch ◽  
Morgan T. Kirk ◽  
...  
Keyword(s):  
Life History ◽  
Spatial Variation ◽  
Life History Theory ◽  
The Arctic ◽  
Adult Survival ◽  
Annual Survival ◽  
Weak Support ◽  
Branta Bernicla ◽  
Black Brant ◽  
Branta Bernicla Nigricans

Abstract We used capture–recapture methods to estimate adult survival rates for adult female Black Brant (Branta bernicla nigricans; hereafter “brant”) from three colonies in Alaska, two on the Yukon-Kuskokwim Delta, and one on Alaska's Arctic coast. Costs of migration and reproductive effort varied among those colonies, enabling us to examine variation in survival in relation to variation in these other variables. We used the Barker model in program MARK to estimate true annual survival for brant from the three colonies. Models allowing for spatial variation in survival were among the most parsimonious models but were indistinguishable from a model with no spatial variation. Point estimates of annual survival were slightly higher for brant from the Arctic (0.90 ± 0.036) than for brant from either Tutakoke River (0.85 ± 0.004) or Kokechik Bay (0.86 ± 0.011). Thus, our survival estimates do not support a hypothesis that the cost of longer migrations or harvest experienced by brant from the Arctic reduced their annual survival relative to brant from the Yukon-Kuskokwim Delta. Spatial variation in survival provides weak support for life-history theory because brant from the region with lower reproductive investment had slightly higher survival.

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