Interannual Variation In Growth Research Articles

Growth and climatic response of male and female trees of Austrocedrus chilensis, a dioecious conifer from the temperate forests of southern South America

In dioecious plants, males and females usually differ in the amount of resources devoted to reproduction. As a consequence of potential tradeoffs between reproductive and vegetative functions, sexes can exhibit distinctive growth patterns. We analyzed differences between male and female trees in average radial growth, interannual radial growth variation, and, through dendrochronological reconstruction, growth response to temperature and rainfall in 15 stands of the dioecious conifer Austrocedrus chilensis, occurring in Nahuel Huapi National Park, Argentina. Patterns of resource allocation in this species are typical of most dioecious plants in that females invest several times more carbon and nitrogen into reproduction than males. Consistent with theory, we found that in seven stands males grew faster than females. In three stands, however, females grew faster than males, whereas in the other five no significant differences between sexes were detected. In addition, within a stand one sex could grow faster than the other during some periods, while at other times the reverse was true. We found no evidence that females exhibited higher interannual growth variation than males. Growth responded positively to precipitation and negatively to temperature over the growing season. However, neither the direction nor the magnitude of the correlations between annual growth and seasonal climatic variables differed between males and females. Possible factors that could contribute to reducing the differences in the cost of reproduction between males and females in A. chilensis are i) the photosynthetic activity of developing female cones, ii) differences in carbon assimilation efficiency between sexes, and iii) a more strict regulation of the number of reproductive structures produced annually among the females. We hypothesize that the spatio-temporal mosaic in growth differences between sexes we report here might be attributed to chance colonization of disturbed sites by either fast- or slow-growing male and female genotypes rather than by stand characteristics. A general implication is that very little might be concluded about the consequences of the differential cost of reproduction between sexes in any dioecious species from studies focused on a single population or even a few populations.

Biophysical modeling of larval Baltic cod (Gadus morhua) growth and survival

A coupled hydrodynamic–trophodynamic individual-based model of drift and feeding was utilized to analyze the intra- and inter-annual variability in growth and survival of cod (Gadus morhua) larvae in the central Baltic Sea. Highly temporally and spatially resolved simulated flow fields were used to investigate the potential drift of larval cod from the centre of spawning effort in the Bornholm Basin towards their nursery areas through temporally resolved three-dimensional idealized prey fields. Stomach content analyses of larval cod from the Bornholm Basin revealed calanoid copepod nauplii and early copepodite stages to be the preferred prey organisms. The results of the model runs indicate that larval cod changed from a nonlimited to a food-limited stage because of the strong decrease in abundance of the calanoid copepod Pseudocalanus elongatus during the last two decades. The modeling study revealed retention and dispersal from the main spawning ground to be a key process influencing larval survival. When P. elongatus was available in the prey fields, high cod larval survival rates occurred in spring and early summer. In contrast, when P. elongatus was not available, hatched larvae had only high survival probabilities later in the year or if they were transported into shallower coastal regions.

Growth response of ponderosa pine (Pinus ponderosa) to climate in the eastern Cascade Mountains, Washington, U.S.A.: Implications for climatic change1

Climatic change is expected to cause dramatic shifts in low-elevation treeline in mountainous environments. Ponderosa pine (Pinus ponderosa) were sampled across an elevation gradient adjacent to the Methow Valley of the Okanogan National Forest in the eastern Cascades, Washington to examine the potential response of ponderosa pine to climatic change. Response function analyses were used to compare climate-growth relationships among 12 sites, four elevations on three different mountains. Response function analysis attributes 42-55% of the inter-annual variation in growth to climate. Growth is positively correlated with November precipitation prior to the growing season on all 12 sites, suggesting that November precipitation is critical for increased root growth, increased nutrient availability through decomposition, building snowpack, or non-growing season photosynthesis and carbon storage. Growth is positively correlated with previous October, January, June, and July precipitation at more than one site. Temperature is not correlated with growth on any sites. Climate models predict that the Pacific Northwest will experience warmer and wetter winters and drier summers in the future. Growth-climate correlations suggest that the short-term growth response of ponderosa pine is most sensitive to non-growing season precipitation. Therefore, predicting ponderosa pine’s response to projected climatic change is problematic, with wetter falls increasing growth and drier summers decreasing growth. Our results indicate that ponderosa pine is much more sensitive to precipitation than temperature and that any predictions of this arid species’ response to climatic change are difficult, due to uncertainty in predicting future precipitation patterns.

Interannual variability in growth of walleye pollock, Theragra chalcogramma, in the central Bering Sea

Interannual variability in growth of walleye pollock, Theragra chalcogramma, was examined. Adult walleye pollock were collected from the central Bering Sea (Aleutian Basin) from 1978 to 1999. Average fork lengths were found to be approximately 47 cm during the 1970–80s, this increased to 56 cm in the late 1990s. Age was determined for 4805 individuals using the otolith break and burn method. Ages ranged from 5–23 years and the year classes of 1978 and 1989 were dominant in the 1980s and the 1990s, respectively. Fish had significantly larger length‐at‐age in the 1990s compared to the 1970–80s, and interannual variability in age–length relationship was clearly observed. Taking into consideration a recent decrease of the walleye pollock biomass in the central Bering Sea, density‐dependent growth was supported as one possibility of the growth variability. At the same time, we could not rule out the possibility that oceanographic variability affected the growth of walleye pollock in the area.

Interannual growth variation in fish and tree rings

Interannual growth variations were compared among neighbouring populations of lake sturgeon (Acipenser fulvescens) and white spruce (Picea glauca), white pine (Pinus strobus), and red pine (Pinus resinosa). Measures of growth were obtained by removing long-term trends from widths of rings in the hard tissues of both aquatic and terrestrial organisms and assembling these measures into growth chronologies. Interannual growth variations were negatively correlated (r) between sturgeon and nearby tree population chronologies for those fish populations that displayed strong interseries correlation (mean r). The three sturgeon population chronologies developed from individuals that displayed the lowest interseries correlation coefficients failed to display significant correlation with tree growth. The results of this investigation indicate that the negative relationships between fish and tree growth may be related to annual fluctuations in air temperature. In general, fish population chronologies displayed positive correlation with measures of air temperature during the current season of growth, while tree population chronologies displayed negative correlation with air temperatures from either the current or the previous season of growth.

Suitability of Lake Sturgeon Growth Rings inChronology Development

The purpose of this investigation was to determine if ring widths in the cross section of lake sturgeon pectoral fin rays satisfy three criteria required of structures used in the development of growth chronologies. First, ring widths must be related to the overall somatic growth of the organism. Second, ring widths must demonstrate synchrony of interannual growth variation among individuals within a population. Finally, fin ray rings and growth chronologies should be related to both interpopulation and interannual variations of known environmental factors. This research indicated that ring widths document variations in somatic growth. Average fin ray cross-sectional radii at age 25 were related to total length using data from seven populations sampled across North America. This investigation also suggested that growth ring widths were influenced by large-scale, population-wide, extrinsic factors in two ways. First, differences between populations in fin ray cross-sectional radii at age 25 were strongly correlated with mean annual, summer, and winter air temperatures. Second, growth chronologies developed from populations that demonstrate significant synchrony of interannual growth variations among members are consistently positively correlated to past air-temperature records. This research has provided evidence that growth rings contained in the cross section of the lake sturgeon pectoral fin ray can be used in the construction of growth chronologies.

Interannual growth variation in fish and tree rings

Interannual growth variations were compared among neighbouring populations of lake sturgeon (Acipenser fulvescens) and white spruce (Picea glauca), white pine (Pinus strobus), and red pine (Pinus resinosa). Measures of growth were obtained by removing long-term trends from widths of rings in the hard tissues of both aquatic and terrestrial organisms and assembling these measures into growth chronologies. Interannual growth variations were negatively correlated (r) between sturgeon and nearby tree population chronologies for those fish populations that displayed strong interseries correlation (mean r). The three sturgeon population chronologies developed from individuals that displayed the lowest interseries correlation coefficients failed to display significant correlation with tree growth. The results of this investigation indicate that the negative relationships between fish and tree growth may be related to annual fluctuations in air temperature. In general, fish population chronologies displayed posit...

Lake sturgeon (Acipenser fulvescens) growth chronologies

We used annual increments in the pectoral fin rays of lake sturgeon (Acipenser fulvescens) to assess growth synchrony. We based our decision criteria on correlation among individual chronologies developed from samples collected in the Saskatchewan River, Saskatchewan, and Lake St. Clair and the Mattagami River, Ontario. Initially, correlations among chronologies were not significant within these three populations. However, as mean ageing error was reduced, correlations among chronologies increased to significant levels in samples from the Saskatchewan River and Lake St. Clair. Correlations were not significant among consistently aged fish sampled from the Mattagami River. We conclude that interannual growth variation in lake sturgeon is influenced by population-wide extrinsic factors in some populations. Our results suggest that both growth synchrony and ageing error should be quantified during the construction of growth chronologies for all organisms.

The effect of interannual variation in growth and condition on haddock recruitment

The relationship between recruitment and spawner biomass assumes that estimates of spawner biomass are proportional to total egg production by the stock. The validity of this assumption is in question for long-lived gadoid stocks; however, estimating total egg production independently of spawner biomass is seldom feasible. An alternative approach is to examine correlations between recruitment and variables likely to be proxies for total egg production by the stock. This indirect approach was used for haddock on the Scotian Shelf. Indices of growth (mean length at age-4) and condition (weight at 50 cm) were used as proxies for the reproductive potential of individual spawners. Both variables were positively correlated with recruitment over a 3-decade period (1964-1995). During the same time period, there was no relationship between recruitment and spawner biomass estimated by Virtual Population Analysis (VPA). This is further evidence that VPA-based spawner biomass is a poor index of the true reproductive potential of the stock. The results highlight the need to develop more accurate/precise measures of total egg production for use in recruitment research.

The effect of interannual variation in growth and condition on haddock recruitment

The effect of interannual variation in growth and condition on haddock recruitment

Nonparametric regression modelling of green sea turtle growth rates (southern Great Barrier Reef)

Somatic growth rates recorded between 1974 and 1991 for green sea turtles Chelorl~a rnydas resident in the southern Great Barrier Reef (sGBR) foraging grounds of the sGBR genetic stock were modelled using nonparametrlc regression. The sampling deslgn in this long-term mark-recapture program was mixed longitudinal and ~ncluded growth records for female and male turtles 1-anglng between 39 and 116 cm CCL (curved carapace length). Distinct sex-specific growth patterns were found, adults displayed constant negligible growth while inter-annual variability in immature female growth attributable to major oceanographic events was evident. Females grew faster than the males from ca 62 to 65 cm CCL with divergent growth patterns following distinct juvenile growth spurts. The expected female size-specific growth rate function was nonmonotonic, rising from recruitment size (>35 cm CCL) to maximum growth of 2.1 cm yr.' at ca 60 cm CCL before declining to negligible growth approaching sexual maturlty at ca 95 to 100 cm CCL. The male size-specific growth rate function was nonmonotonic rising from the sdme recruitment size to maxlmum groiuth of 2 .2 cm yr.' at ca 63 cm CCL before declining faster than females to negligible grotzlth approachlnq sexual maturity at a significantly smaller size, 595 cm CCL Assumlng a post-hatchling pelagic phase of 5 yr, the mean age at sexual maturity for each sex was estimated at 2-40 yr using numer~cal Integration of the expected slze-specific growth rate functions. Expc.cted age-specific growth rate functions for each sex derlved by numerical differentiat~on showed that the juvenile growth s p u ~ t for females resident in the sGBR foraglng grounds occurs at around 9 yr at large since recruitment (60 cm CCL. 214 yr old) and for males at ca 11 yr a t large (63 cm CCL, 216 yr old). Juvenile growth spurts, sex-specific growth, slow size-specific growth rates, inter-annual growth variability of immatures and many decades to sexual maturity are growth characteristics for green sea turtles resident in the sGBR foraging grounds of the sGBR genetic stock. K E Y WORDS: Somatic growth . Green sea turtles . Great Barrier Reef Nonparametrlc regression

Interannual variability in growth of larval and juvenile walleye pollock Theragra chalcogramma in the western Gulf of Alaska, 1983–91

ABSTRACTInterannual variability in growth of larval walleye pollock Theragra chalcogramma was examined from 1983 to 1991 and of juveniles from 1985 to 1990. ANCOVA was used to assess differences in population growth rates, and an alternate method was developed to examine variations between annual length‐at‐age data and average ‘expected’ values over different age groupings. For larvae, the years 1986, 1987, 1989 and 1990 had higher than average length‐at‐age, and 1988 and 1991 had lower than average values. Relationships between growth and SST and larval density were not clear. A tentative relationship between copepod nauplii abundance and larval length‐at‐age was noted. The consequence of larval growth to larval mortality, late larval abundance or recruitment was not clear. We conclude that larval mortality rates are highly variable and tend to mask effects of moderate variability in growth on later abundance. For juveniles, 1987 had significantly lower than average length‐at‐age and 1988 had higher than average values. Although there are few years of data, they tend to support the importance of juvenile growth in the recruitment process. Conditions for the large 1988 year class are documented and discussed, including warm SST, calm winds, relatively low larval growth rates, low abundances of potential predators on larvae, low larval mortality rates, and high juvenile growth rates.

Radial growth patterns and the effects of climate on second-growth Douglas-fir (Pseudotsugamenziesii) in the Siskiyou Mountains, Oregon

Three sites with fire-generated second-growth (70–100 years old) Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in southwestern Oregon were examined using dendroecological techniques to determine (1) temporal patterns of radial growth and (2) the effects of variation in climate on growth. Long-term patterns of radial growth vary among sites, but similar interannual variation in radial growth indicates a common response to regional climate. Growth is positively correlated with the Palmer Drought Severity Index and precipitation during summer. Furthermore, growth is positively correlated with precipitation during autumn prior to the growth year, which suggests the benefits of soil moisture recharge for subsequent stemwood production. Annual precipitation is strongly seasonal, and soil moisture stress in summer is apparently severe enough to be the dominant climatic influence on radial growth. Positive correlations of growth with most monthly temperatures reflect the benefit of warm temperatures on photosynthesis and radial growth during periods of adequate soil moisture. Although coastal Oregon is generally considered to be a high precipitation environment, conditions are clearly dry enough during summer to limit carbon gain in second-growth Douglas-fir. If future climatic conditions result in increased soil moisture stress during summer, productivity of such second-growth stands may decrease below current levels.

Seasonal and interannual variability in growth and maturation of winter-spawningIllex argentinus(Cephalopoda, Ommastrephidae) in the Southwest Atlantic

An investigation was carried out during the Illex argentinus trawl fishery (January-July) in the fishery regions of 42 °S and 45-47 °S off the Exclusive Economic Zone of Argentina between 1985 and 1990. Statoliths of 5,232 squid were sampled and processed to study age and growth patterns in squid, hatched in different months. Among squid of similar ages (within an age interval from 180 to 300 days), the May-hatched squid were the smallest while the September-hatched were largest. Growth rates of squid of the same hatching-months were significantly different according to year, but these differences were considerably smaller than those observed between various hatching-months within one year. The largest individuals at a given age were captured in 1990, and the smallest in 1985. Males and females became mature at age 220-320 and 210-360 days respectively. The maturation period lasts 1.5-2.5 months in males and 1 month in females. Early and late-maturing groups were observed within each hatching-month. The peak. of spawning was in July of 1984, 1986, 1987, in June of 1985 and in August of 1989.

Determining Fish Age from Temporal Signatures in Growth Increments

The temporal signature technique can be used to assign age to fish that show an incomplete or indistinct growth history at the margins of their scales. The temporal signature technique matches part of an individual's "environmental" growth history to characteristic patterns found in a master chronology that was developed from reliably aged specimens of a species in a particular environment. An error sum of squares measures the concordance between an individual's environmental growth history and the master chronology. Ages assigned to walleye (Stizostedion vitreum) by the temporal signature technique and by examination of scales were compared to assess the performance of the new technique. Scale-age agreed with one of the three most likely signature-ages in 67–77% of the comparisons using ail observed increments. These results are purposely conservative because of the methods employed and the nature of the example. All observed growth increments should be used in applying the temporal signature technique, but age may still be accurately assigned if as few as three increments are available. The temporal signature technique will perform best for species that exhibit high interannual variation in growth.

Relationships among Smolt Size, Marine Growth, and Sea Age at Maturity of Atlantic Salmon (Salmo salar) in Northern Spain

Scale analysis indicated that two-sea-winter (2SW) Atlantic salmon (Salmo salar) had a greater growth increment during the first year at sea than 1SW of the same smolt year in the Rivers Narcea and Esva, but no differences were found between sea age-classes in the River Cares. Interannual variation in marine growth was synchronized among rivers. Variation among years was greater than variation between sea age-classes, suggesting that marine growth per se does not determine age at maturity. In the River Narcea, 2SW salmon were larger than 1SW at the end of the first marine period, but differences between sea age-groups were not significant in the other two rivers. Some of this variability could be attributed to differences in size at smolting; for two rivers (Esva and Cares), 1SW salmon had been larger as smolts than 2SW salmon. Length increment during the first marine growth period was inversely correlated with smolt size (age-1 smolts); in spite of that compensatory effect, large smolts tended to maintain their size advantage at the time of formation of the first marine annulus, as indicated by positive correlations between smolt size and length at the first sea winter.

Monitoring of seabirds in the Benguela upwelling system: can seabirds be used as indicators and predictors of change in the marine environment?

Historical and contemporary data on Benguela seabirds assumed to be responsive to changes in food availability are reviewed as potential indicators and predictors of change in the ecosystem. Cyclic variations in the annual yields of seabird products evident at decadal long time-scales may reflect fluctuations in prey populations at similar periods. However, no such relationship has been demonstrated and consequently the value of such annual yields as indicators is not proved. More recently, interannual variation in diets, foraging effort, breeding success and chick growth of two of the three most abundant species of seabird in the ecosystem have been examined in relation to changes in prey abundance. Although the relative abundance of important forage species in the diets of both species of seabird have reflected regional changes in the absolute abundance of these prey, changes in the values of other parameters thought to reflect food availability were not consistently correlated between and within specie...

Density-Dependent Growth of Age 1 English Sole (Parophrys vetuls) in Oregon and Washington Coastal Waters

We tested whether English sole (Parophrys vetulus) in Oregon and Washington waters show density-dependent growth. We found that there is a significant negative effect of cohort abundance on annual growth rate of age 1 fish, but not on growth of ages 2–7. Unlike most similar studies of density dependence, this result was not confounded by time trends in abundance and growth. The multiple regression of age 1 growth on cohort abundance and temperature accounted for 91% of the interannual variation in growth, which was a significant increase in r2 over that of the previously published relation with temperature alone. However, stock assessments which take into account only the previously published temperature effect on growth for this stock will probably not seriously overestimate the impact of management regulations which increase cohort abundance.

Determination of seasonal and interannual variation in New Zealand pasture growth from NOAA-7 data

The normalized vegetation index (NVI) has been calculated from afternoon overpasses of NOAA-7 for two important farming regions of New Zealand, approximately 1000 k 2 in area, for the period from October 1981 through June 1984. The uniform nature of the terrain and farming practices in these areas make them ideal targets for remote sensing from satellites with limited spatial resolution. The frequency of useful data coverage has been increased by sampling within cloud-free parts of a partly cloudy target area and also by deriving an empirical correction for off-nadir view angles. Daily area-mean rainfall and soil moisture were estimated for both regions and monthly area-mean pasture growth for one of them. The NVI was found to reflect the varying rainfall and soil moisture on time scales of one week or more during the growing season and between years. A correlation of 0.81 was found between NVI and pasture growth on a monthly mean basis. These results suggest that operational satellite monitoring of these and other areas would provide valuable assistance in agricultural management and forward planning.