EFFECT OF FOOD SUPPLEMENTATION ON JUVENILE GROWTH AND SURVIVAL IN MARMOTA FLAVIVENTRIS

<p>Realistic population models and effective conservation strategies require a thorough understanding of the processes that drive variation in individual growth and survival, particularly within life stages that are subject to high mortality. For fragmented marine populations it is also important to consider how processes driving variation performance may vary through space and time. In this study I assess the interaction of two primary factors driving juvenile demography: benthic habitat composition and larval history traits, in a temperate reef fish, Forsterygion lapillum (the common triplefin). It is well understood that juveniles of many marine organisms are closely associated with structured nearshore habitats as they provide resources (refuge and food sources) that are critical for juvenile growth and/or survival. Nursery habitats are often assessed using measures of fitness of juveniles inhabiting them (e.g. rates of growth). However individual fitness measures may not only be indicative of conditions experienced in the benthic phase, but also an individual's prior history. Recent evidence suggests that variation in larval traits at settlement (e.g., size and age at settlement, larval growth rate) can impact on subsequent ecological performance (e.g., feeding ability and/or predator avoidance) and therefore influence subsequent fitness (i.e. rates of growth and/or probabilities of survival). I used otolith microstructure to assess separate and joint effects of habitat composition and larval traits on the growth of young F. lapillum. Both macroalgal composition of habitat patches and larval traits affected juvenile growth rates, and results suggested that habitat composition may have the potential to mediate fitness-related advantages that may accrue to certain individuals as a result of paternal effects and/or larval dispersal history. Quantifying spatio-temporal variability in the post-settlement fitness of Individuals with that differ in larval traits is essential for effective spatial management of marine populations. I further explore the joint effects of macroalgal composition and larval traits, within the context of additional spatial and temporal environmental variation. Results provide direct evidence that habitat can mediate the strength of carryover effects, but that the impact of habitat was variable between local populations and settlement events through time. In chapter 4 of my thesis, I focus on how small-scale variation in macroalgal composition within a nursery habitat (while controlling for individual variation) can affect the strength of density dependent growth and survival rates of F. lapillum. Density-dependent survival is evident during the first 30 days after settlement, and the strength of density dependence varied as a function of macroalgal composition. Resulting variation in estimates of nursery value (i.e., the number of late-stage juveniles produced per area unit of habitat) highlight the importance of incorporating local scale variation in juvenile demography into assessments of nursery habitat. Lastly, I assess a potential strategy of fishes to persist in a wide range of benthic environments. The ability to adjust traits (i.e., phenotypic plasticity) may allow organisms that encounter a range of unpredictable environmental conditions to maximise fitness within a single generation. In chapter 5 I explore patterns of variation in morphology of juvenile F. lapillum from two different subpopulations and from different macroalgal habitats. I evaluate possible evidence for constraints on morphological variation arising from variation in growth rate prior to and following settlement. Results suggest that for organisms with complex life cycles, variation in growth rates experienced during dispersal may constrain plasticity in later stages.</p>

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Effect of Food Availability on Arrival and Departure Decisions of Harlequin Ducks at Diurnal Feeding Grounds

The Condor ◽

10.1093/condor/103.4.870 ◽

2001 ◽

Vol 103 (4) ◽

pp. 870-874 ◽

Cited By ~ 4

Author(s):

Michael S. Rodway ◽

Fred Cooke

Keyword(s):

Food Availability ◽

Food Supplementation ◽

Natural Food ◽

Clupea Pallasi ◽

Histrionicus Histrionicus ◽

Before And After ◽

Harlequin Ducks ◽

Near Shore ◽

Effect Of Food ◽

Departure Decisions

Abstract We investigated three types of decisions made by Harlequin Ducks (Histrionicus histrionicus) in moving between nearshore feeding and offshore resting areas: when to move, whether to move synchronously, and whether to form dense flocks on the roosting grounds. We used the spawning of Pacific herring (Clupea pallasi) as a natural food-supplementation experiment. Birds arrived at nearshore feeding areas a few minutes later and departed almost an hour earlier relative to sunrise and sunset when spawn was available than before and after. Cloud cover and high winds resulted in earlier departures, especially during spawning. Arriving, departing, and offshore groups consisted most frequently of two ducks, and birds showed little tendency to synchronize movements or to form dense flocks when resting. Results indicate that Harlequin Ducks avoid crepuscular and nocturnal periods near shore when not constrained by food availability and the length of daylight in which to feed. Efecto de la Disponibilidad de Alimento en las Decisiones de Arribo y Partida de Histrionicus histrionicus en Áreas de Alimentación Diurna Resumen. Investigamos tres tipos de decisiones hechas por Histrionicus histrionicus (Pato Arlequín) al moverse entre áreas de alimentación cercanas a la costa y áreas de reposo mar adentro: cuándo moverse, si se mueven de modo sincrónico, y si forman bandadas densas en las áreas de reposo. Utilizamos el desove del arenque del Pacífico (Clupea pallasi) como un experimento de suplemento de alimento natural. En relación al amanecer y anochecer, las aves llegaron a las áreas de alimentación cercanas a la costa unos minutos después y se fueron casi una hora más temprano cuando los huevos de peces estuvieron disponibles que cuando no lo estuvieron, ya sea antes o después. Cobertura de nubes y fuertes vientos trajeron aparejadas partidas más tempranas, especialmente durante la etapa de desove. Los grupos que llegaban, partían y los que se encontraban mar adentro estuvieron en su mayoría conformados por dos patos, y las aves en general no tendieron a sincronizar sus movimientos o a formar grupos densos durante el reposo. Los resultados indican que H. histrionicus evita permanecer cerca de la costa durante períodos crepusculares y nocturnos cuando no se haya limitado por la disponibilidad de alimentos y por la cantidad de horas de luz para alimentarse.

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EFFECT OF FOOD SUPPLEMENTATION DURING PREGNANCY ON BIRTHWEIGHT

Obstetrical & Gynecological Survey ◽

10.1097/00006254-197605000-00012 ◽

1976 ◽

Vol 31 (5) ◽

pp. 384-388 ◽

Cited By ~ 2

Author(s):

AARON LECHTIG ◽

JEAN-PIERRE HABICHT ◽

HERNAN DELGADO ◽

ROBERT E. KLEIN ◽

CHARLES YARBROUGH ◽

...

Keyword(s):

Food Supplementation ◽

Effect Of Food

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Influence of food restriction on the reproduction and larval performance of matrinxã, Brycon amazonicus (Spix and Agassiz, 1829)

Brazilian Journal of Biology ◽

10.1590/s1519-69842008000400024 ◽

2008 ◽

Vol 68 (4) ◽

pp. 869-873 ◽

Cited By ~ 9

Author(s):

ACS. Camargo ◽

EC. Urbinati

Keyword(s):

Food Restriction ◽

Fish Larvae ◽

Larval Performance ◽

Growth And Survival ◽

Growth Measurement ◽

Influence Of Food ◽

Effect Of Food ◽

Similar Weight ◽

The Mean ◽

Fish Tank

This work evaluated the effect of food restriction and refeeding of matrinxã females, Brycon amazonicus, on their reproductive performance and on the growth and survival of the progeny. Broodstocks were distributed in 8 earthen tanks (15 fish/tank) and fish from 4 tanks were fed daily (G1) while fish from the other 4 tanks were fed for 3 days and not fed for 2 days (G2) during 6 months prior to artificial spawning. Among the induced females, 57% in G1 group and 45% in G2 group spawned and the mean egg weights were 208.1 g (G1) and 131.6 g (G2). Oocytes of G2 fish were smaller (1.017 ± 0.003 mm) than oocytes of G1 fish (1.048 ± 0.002 mm). Fertilization (71.91 ± 12.6% and 61.18 ± 13.7%) and hatching (61.28 ± 33.9% and 67.50 ± 23.4%) rates did not differ between G1 and G2 fish. Larvae were collected at hatching and at 24, 48 and 72 hours of incubation and fixed for growth measurement. After incubation, fry were transferred to aquaria and sampled 1, 5, 9 and 15 days later. G1 and G2 larvae had similar weight (1.51 ± 0.15 and 1.46 ± 0.07 mg) but the G2 length was significantly higher (6.26 ± 0.13 and 6.74 ± 0.14 mm). By the ninth day of rearing, G2 fry had higher weight (13.6 ± 0.26 and 18.9 ± 0.07 mg) and length (11.8 ± 0.09 and 14.5 ± 0.04 mm) but by the fifteenth day, G1 fry had higher weight (90.2 ± 1.19 and 68.6 ± 0.77 mg) and length (18.8 ± 0.16 and 18.5 ± 0.04 mm) than G2 fry. By the ninth day of rearing, when fry are recommended to be transferred to outdoor tanks, G2 fry were larger and after 15 days, fry produced by restricted-fed females showed higher survival. The survival rate of G2 progeny by the fifteenth day was significantly higher (24.7 ± 2.07%) than that of G1 progeny (19.2 ± 1.91%). The ration restriction (35% reduction) imposed on matrinxã broodstock during 6 months prior to spawning reduced the number of spawned females and the egg amount, but it did not affect fertilization and hatching rates. Otherwise restricted-female larvae were larger and presented higher survival.

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Mariculture of the Oyster Toadfish: Juvenile Growth and Survival

North American Journal of Aquaculture ◽

10.1577/c02-056 ◽

2003 ◽

Vol 65 (4) ◽

pp. 289-299 ◽

Cited By ~ 9

Author(s):

Allen Mensinger ◽

Nichole Price ◽

Hazel Richmond ◽

John Forsythe ◽

Roger Hanlon

Keyword(s):

Juvenile Growth ◽

Growth And Survival ◽

Oyster Toadfish

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Juvenile growth and survival under dietary restriction: are males and females equal?

Oikos ◽

10.1111/j.0030-1299.2005.14163.x ◽

2005 ◽

Vol 111 (2) ◽

pp. 368-376 ◽

Cited By ~ 37

Author(s):

J.-F. Le Galliard ◽

R. Ferriere ◽

J. Clobert

Keyword(s):

Dietary Restriction ◽

Juvenile Growth ◽

Growth And Survival ◽

Males And Females

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The impact of a vertically transmitted microsporidian, Nosema granulosis on the fitness of its Gammarus duebeni host under stressful environmental conditions

Parasitology ◽

10.1017/s003118200200269x ◽

2003 ◽

Vol 126 (2) ◽

pp. 119-124 ◽

Cited By ~ 22

Author(s):

A. KELLY ◽

M. J. HATCHER ◽

A. M. DUNN

Keyword(s):

Environmental Conditions ◽

Parasite Transmission ◽

Juvenile Growth ◽

Microsporidian Parasite ◽

Growth And Survival ◽

Host Growth ◽

Limited Food ◽

Selection For ◽

Adverse Environmental Conditions ◽

The Impact

Although purely vertically transmitted parasites are predicted to cause low pathogenicity in their hosts, the effects of such parasites on host fitness under stressful environmental conditions have not previously been assessed. Here, we investigate the effects of Nosema granulosis, a vertically transmitted, microsporidian parasite of the brackish water amphipod Gammarus duebeni, on host growth and survival under conditions of host–host competition and limited food. The parasite had no effect on host survival, but caused a reduction in juvenile growth. Stressful environmental conditions also led to a reduction in G. duebeni growth. However, we found no evidence to support the prediction that parasitized hosts would suffer a greater reduction in fitness than uninfected hosts under adverse environmental conditions. We interpret our results in the context of selection for successful vertical parasite transmission.

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