Early Life History

Please indicate author's corrections in blue, setting errors in red ... Environmental Biology of Fishes 51: 353–368, 1998. © 1998 Kluwer Academic Publishers. Printed in the Netherlands. ... Diel and distributional abundance patterns of fish embryos and larvae in the

Experimental results suggest that anadromous salmon and trout learn (imprint) the odors of their natal site just prior to or during seaward migration. In contrast, information on the life histories of several species and the genetic structure of populations indicate that they must imprint earlier in life, probably during incubation in the gravel or when they emerge as free-swimming fry. To test the hypothesis that sockeye salmon (Oncorhynchus nerka) home to their incubation-emergence sites (rather than just to the lake where they reared before migrating to sea), we took advantage of the natural variation in otolith microstructure caused by differences in thermal regimes during incubation. We collected otoliths from adult sockeye salmon that returned to discrete spawning areas in Iliamna Lake, Alaska, and Lake Washington, Washington, and, in blind trials, these were classified based on comparison with otoliths from juveniles from the same sites and using information on site-specific ...

The spatial distribution of neutral genetic diversity is mainly influenced by barriers to dispersal. The nature of such barriers varies according to the dispersal means and capabilities of the organisms concerned. Although these barriers are often obvious on land, in the ocean they can be more difficult to identify. Determining the relative influence of physical and biotic factors on genetic connectivity remains a major challenge for marine ecologists. Here, we compare gene flow patterns of 7 littoral fish species from 6 families with a range of early-life-history traits sampled at the same geographic locations across common environmental discontinuities in the form of oceanic fronts in the Western Mediterranean. We show that these fronts represent major barriers to gene flow and have a strong influence on the population genetic structure of some fish species. We also found no significant relation between the early-life-history traits most commonly investigated (egg type, pelagic la...

Variation in and among early life history traits of laboratory-reared winter flounder Pseudopleuronectes americanus. ... The authors analyzed variation in and among early life history traits of laboratory-reared winter flounder Pseudopleuronectes americanus . ...

Dynamics of growth in the early life history of shortbelly rockfish Sebastes jordani. ... The relationship between length and age of larval and juvenile shortbelly rockfish Sebastes jordani , determined from otolith microstructure, is complex. ...

... The annual mean surface water tem-perature is 27°C, ranging from 26°C in winter to ... However, the peak occurrence of neonates in winter suggests this season as main period of parturition; this is con-firmed by the large capture of juveniles with healed umbilical scars in spring. ...

In red deer, yearling antler length is a largely nutrition-mediated phenotypic character, and is therefore sometimes used as an indirect estimate of range quality and population condition. However, the parameters affecting yearling antler length have been little studied. We analyse the contributions of density, weather and maternal effects on yearling antler length of 581 individual stags born 1970-1996 on the Isle of Rum (Scotland). We show that antler length is a good measure of yearling condition: the probability of overwinter survival in yearlings that developed antlers was 3 times higher than for yearlings that did not develop antlers, and yearling antler length was correlated with the number of antler points the following year. Between years, variation in yearling antler length was best explained by variation in red deer density and June temperature at 12 months of age. Both of these variables were negatively correlated with antler length, and most likely this effect is due to changes in nutrient availability. Population density affects biomass availability for the individual, while low temperatures in early summer prolong the availability of high forage quality. At the individual level, antler length increased with birth weight and decreased with birth date, reflecting the persistent and pervasive influence of conditions in early life.

Lack of tree regeneration and persistency of species-poor shrublands represent a growing problem across Mediterranean evergreen oak forests. What constrains forest regeneration is poorly understood, and restoration attempts have been largely unsuccessful. We assessed the contribution of four different mechanisms of tree recruitment limitation (that is, source, dispersal, germination, and establishment) in a cork oak (Quercus suber) system in southern

population dynamics. That role depends on the vital rates (transitions) from seed production to sapling stages and on overall population growth. To determine the state of our understanding of recruitment limitation we examined how well we can estimate parameters corresponding to these vital rates. Our two-part analysis consists of (1) a survey of published literature to determine the spatial and temporal scale of sampling that is basis for parameter estimates, and (2) an analysis of extensive data sets to evaluate sampling intensity found in the literature. We find that published studies focus on fine spatial scales, emphasizing #large numbers of small samples within a single stand, and tend not to sample multiple stands or variability across landscapes. Where multiple stands are sampled, sampling is often inconsistent. Sampling of seed rain, seed banks, and seedlings typically span C 1 yr and rarely last 5 yr. Most studies of seeding establishment and growth consider effects of a s...