Mean Absolute Growth Rate Research Articles

Effect of dietary protein level on growth, food utilization, food conversion and survival rate of giant trevally (Caranx ignobilis)

Background: Proper feed formulation is required for successful fish farming activities. Therefore, it is necessary for fish feed to provide optimal growth so that the cultivation business generates profits. Currently, there is very limited information about the appropriate feed for Caranx ignobilis, causing problems with its development. This study aims to provide feed with different protein levels to C. ignobilis. Methods: We will examine the protein levels’ effects on the daily growth rate (DGR), specific growth rate (SGR), absolute growth rate (AGR), feed conversion ratio (FCR), feed efficiency (FE), and survival rate (SR). This research was conducted for 35 days, from June to October 2017, at the Center Brackiswater Aquaculture Development (BPBAP) Ujung Batee, Ministry of Marine Affairs and Fisheries, Aceh Besar, Indonesia. This study used a completely randomized design method, with five treatment levels (30%, 40%, 50%, 60%, and 70% protein feed) and four replications. Results: The results showed that feeding with different proteins on C. ignobilis had a significant effect on the mean values ​​of DGR, SGR, AGR, FCR, FE, and SR. The 50% protein feed gave the best results for C. ignobilis, with a mean DGR value of 0.267 ± 0.005 g / day, a mean SGR of 1.722 ± 0.030% / day, a mean AGR of 0.081 ± 0.003 cm/day, a mean FCR of 1.290, a mean FE 77.755% and a mean SR was 86.667%. Conclusions: Furthermore, feed treatment with increased protein content between 30%–50% has a positive correlation with the growth of C. ignobilis. However, the ability to grow fish will decrease if the feed protein content is >50%.

Is culture performance of juvenile sandfish, Holothuria scabra, in ocean-based nursery systems influenced by proximity to milkfish (Chanos chanos) farms and hapa net mesh size?

The impacts of proximity to milkfish farms (i.e. ‘close’, ‘intermediate’ and ‘distant’) and different hapa net mesh sizes (i.e. 400 μm and 1 mm) on periphyton characteristics and growth performance of sandfish, Holothuria scabra, juveniles (4.6 ± 0.1 mm), were evaluated in a 30-day field experiment in the Guiguiwanen Channel at Bolinao, North-western Philippines. Growth and survival of sandfish juveniles were determined twice, and chlorophyll a and ash-free dry weight (AFDW) of periphyton were monitored every 5 days during the study. Opisthobranchs that recruited inside the hapa nets were identified and counted during monitoring. Survival of sandfish juveniles differed significantly between sites but was not influenced by mesh size by day 15. Survival was significantly higher at the intermediate site by day 15. Juvenile survival was significantly higher in 400 μm mesh hapa nets across all sites by day 30. Result showed that mean length and absolute growth rates (AGR) of sandfish juveniles were significantly influenced by mesh size but not by site at day 15. Juveniles reared in the 1 mm mesh hapa nets were larger and grew faster by day 15. However, by day 30, mean length and AGR of sandfish juveniles were significantly affected by site but not mesh size. Juveniles reared at the close site were significantly larger and grew faster than those reared at the intermediate site while mean length and AGR of juveniles reared at the distant site were not significantly different to those cultured at either the close or intermediate sites. Growth rates of juveniles were lower on day 30 compared to day 15 possibly resulting from reduced food availability, as indicated by lower periphyton AFDW, resulting from inter- and intraspecific competition. A positive correlation was found between AGR and the number of surviving sandfish juveniles by day 15, while no correlation between the two parameters was observed by day 30 indicating that reduced growth rates were not mediated by interspecific stocking density, but most likely resulted from high intraspecific grazing pressure. Chlorophyll a content of periphyton was higher during the second half of the experiment; however, total periphyton biomass (as AFDW) generally decreased overtime. This reduced food availability coincided with the higher number of opisthobranchs in the hapa nets by day 30. Results showed that sandfish juveniles can grow in an environment with varying levels of nutrient enrichment, however, areas close to mariculture activity may support improved growth because of resulting increases in periphyton biomass. Additionally, the use of finer mesh (400 μm) hapa nets positively impacted juvenile survival and would support earlier transfer of juveniles from the hatchery to the ocean reducing husbandry inputs and costs.

First assessment of the potential for coculture of sandfish (Holothuria scabra) with Babylon snail (Babylonia areolata) in Vietnam

AbstractThe potential for the coculture of sandfish, Holothuria scabra and Babylon snail, Babylonia areolata was investigated. Sandfish (weight 1.87 ± 0.41 g) were cultured at low (25 ind/m2; 46.75 g/m2), medium (50 ind/m2; 93.5 g/m2), and high (100 ind/m2; 187 g/m2) densities in monoculture and in coculture with Babylonia at a density of 400 ind/m2 (208 g/m2). In monoculture, sandfish were provided with 1 g m−2 day−1 commercial prawn starter feed. In coculture, trash fish provided for Babylonia (5% total wet weight per day) was the only food input. Sandfish survival over the 84‐day experiment period was reduced in coculture treatments (77.60 vs. 97.22%) but was in line with expected survival rates (80–90%) of commercial sandfish culture. Mean sandfish weight gain and absolute growth rate were around 37% greater in coculture (mean weight gain 13.42 ± 2.90 g vs. 9.77 ± 2.54 g over 84 days). No differences in Babylonia growth rate or survival were evident between sandfish density treatments. Sediment organic matter content did not differ significantly between monoculture (0.43 ± 0.03%) and coculture (0.55 ± 0.06%) treatments, but the latter had elevated concentrations of ammonia. Results provide a basis for further development of land‐based pond coculture systems for sandfish and Babylonia.

Comparisons of Growth and Survival Performance Among Selected Families and Wild Populations of Fenneropenaeus chinensis

In this study, families of selected population for growth (SP_BWT), selected population for white spot syndrome virus (WSSV) resistance (SP_RW), Bohai wild population (WP_BH) and Huanghai wild population (WP_HH) of F. chinensis were constructed through artificial insemination and with the standardized procedure of larvae rearing. Growth and survival performance were studied among four populations after a 70 days common test. The results showed that the maximum least square mean of body weight was 17.50 g in SP_BWT while the minimum was 13.03 g in WP_HH. Compared with WP_BH, body weight of SP_BWT increased by 23.41% (P 0.05). Body weights of SP_BWT and SP_RW were significantly higher than that of WP_HH, which increased by 34.31% (P < 0.01) and 22.10% (P < 0.05), respectively. The mean AGR of four populations was 0.19, 0.18, 0.17 and 0.16 g d−1, respectively. Coefficient of variation of body weight among four populations was high, which ranged from 32.67% to 35.25%. Such a range showed that there was the potentiality for further improvement in selected populations. Coefficient of variation of survival rate among four populations was low, varying between 3.20% and 5.90%. The difference of survival was highly significant (P < 0.01) between SP_BWT and WP_BH, and significant (P < 0.05) between SP_RW and WP_BH. However, no significant difference among other populations (P < 0.05) was observed. Different growth performances were also observed among different families in each population. The body weight of 798F family was the highest. The absolute growth rate (AGR) was 0.25 g d−1, 150% higher than that of the lowest one, 0.1 g d−1 in 807F family. Survival rate of families among four populations was different. The highest was 94.74%, and the lowest was 71.88%.

Akumulacija suve materije ozime pšenice i ječma u različitim rokovima setve

Dry matter accumulation is one of the best estimates for crop reaction to the effect of genotype or environmental factors. However, there is a lack of information about comparative crop growth between wheat and barley under conditions of the Pannonian climate. The objectives of this work were to study and compare the patterns of biomass accumulation in wheat and barley, and identify the role of the logistic curve parameters in the determination of the final biomass. Therefore, field trials with two two-row winter barley and two winter wheat cultivars were carried out in two successive growing seasons with four sowing dates. Results from our study showed that grain yield and crop biomass were under significant influence of cultivar and sowing date in both growing seasons. The highest grain yield and crop biomass at maturity were obtained with early sowing - first and second sowing date. There was a significant positive relationship between the crop biomass and grain yield in both species. Barley and wheat had similar strategies for biomass determination. Crop biomass at maturity was positively associated with the duration of growing phases, while the relationship with weighted mean absolute growth rate was negative. Early sowing enables prolongation in duration of different phases of crop biomass accumulation, leading to significant biomass and grain yield increase.

Distribution, hatch-date, growth, and mortality of larval Benthosema pterotum (Pisces: Myctophidae) in the shelf region of the East China Sea

We examined the distribution, hatch-date, growth, and mortality of larval Benthosema pterotum, a dominant pseudoceanic myctophid in the shelf region of the East China Sea, during early autumn when the main spawning has been predicted. This species is a key species in the food web of this area. Larvae were abundant in the area south of Cheju Island (60–80 m depth), corresponding with the adult habitat. Occurrence of the larvae was restricted to the onshore side of the shelf-break salinity front, indicating that this front acted as a barrier restricting the offshore dispersion of the larvae. In the area where the larvae occurred, a cyclonic eddy is formed, which is considered to limit the dispersal of the larvae, enabling them to recruit into the area of adult habitat. Modes of hatch-date appeared from late August to early September and from mid to late September, suggesting that large-scale spawning events occurred at least twice during the spawning season. Since the modes coincided with the new moon period, B. pterotum is suggested to spawn periodically once a month around the new moon, resulting in efficient mating and fertilization. Mean absolute growth rate (0.26 mm d−1) and weight-specific growth rate (18.8% of dry body weight d−1) were higher than previously reported values of other subtropical–tropical myctophids, which would be related to the high food availability in the study area. Daily instantaneous mortality coefficient during the first two weeks after hatching was estimated to be 0.28 d−1 (equivalent to 24.7% mortality d−1).

Distribution, growth and mortality of larval jack mackerel Trachurus japonicus in the southern East China Sea in relation to oceanographic conditions

Distribution, growth and mortality of jack mackerel Trachurus japonicus larvae <10 mm standard length (SL) were investigated in relation to habitat conditions in the southern East China Sea (ECS) in 2005, 2007 and 2009. In all the years, the center of larval distribution shifted northeastward with growth, indicating northeastward entrainment by the Kuroshio branch current. In 2005, the mean habitat temperature of the larvae was ∼2°C lower than the other two years. Mean density of the major prey item Paracalanus spp. in the larval habitat varied interannually, with the highest and lowest values in 2007 and 2005, respectively. The mean absolute growth rate and weight-specific instantaneous growth coefficient (Gw) were highest in 2007 (0.30 mm d−1 and 0.217 d−1, respectively) and lowest in 2005 (0.19 mm d−1 and 0.120 d−1, respectively), corresponding with the habitat temperature and food availability. There was no significant interannual difference in the daily instantaneous mortality coefficient (Z) which ranged from 0.107 d−1 in 2009 to 0.136 d−1 in 2007. The ratio Gw/Z, an index of stage-specific larval survival, was highest (1.60) in 2007 and lowest (1.02) in 2005. The lowest Gw/Z in 2005 corresponded with the lowest recruitment of the juveniles (mainly 50–75 mm SL) in the ECS in 2005. However, Gw/Z in 2007 and 2009 did not clearly correspond with recruitment levels, suggesting that a high Gw/Z is a necessary, but may not be a sufficient, criterion of a strong year-class.

Growth and Development of &lt;i&gt;Gomphrena celosioides&lt;/i&gt; Mart under Screen House Conditions in Ilorin, Southern Guinea Savanna Zone of Nigeria

The pattern of growth of Gomphrena celosioides Mart (Amaranthaceae), a weed in mown grass and lawn commonly used in southern Nigeria for treatment of skin infections and as abortifacient was evaluated in Ilorin (Lat. 8 o 29'N & 8 o 30'N; Long. 4 o 30'E & 4 o 32'E), southern Guinea savanna of Nigeria between 2010 and 2012. Seedlings and soil samples to a depth of 15cm were collected from different locations and enumerated for 15 weeks. G. celosioides seedling had a prolific growth rate, producing many leaves, sparsely branching and excessive flowers within a short period after emergence. The estimated seeds of G. celosioides in soil seedbank were about 885 seeds/m 2 . The growing shoot increased in length as a function of plant age with a mean absolute growth rate of 0.13 g plant -1 day -1 , mean RGR of 0.07 g g -1 day -1 . This result will be valuable in aiding the prediction of G. celosioides infestations in agricultural fields and provide a valuable input in timing of its control. KeyWords : Weed biology, plant growth, seedbank, Gomphrena celosioides Mart,

SCREENING OF SELECTED FOREST TREE SPECIES OF SRI LANKA FOR THEIR RESPONSE TO INCREASING ATMOSPHERIC CARBON DIOXIDE

Investigating the effects of increasing atmospheric CO2 on forest tree species is important asforests playa major role in maintaining the ecological balance of an ecosystem. The objective ofthis study was to determine the response of photosynthesis, and it related physiological parameters,Growth and morphological parameters of selected forest tree species such as Teak (Tectonograndis), J3k (Artocarpus heterophyllusy; Satinwood iChloroxylon swieteniay, and two varieties ofMahogany (Swietenia macrophylla arid Swietenia mahogany) to elevated C02.The experiment was carried out at the Rice Research and Development Institute (RRDI),Batalagoda,lbbagamuwa, from October 2002 to February 2003. Three experimental treatmentswere defined as elevated CO2 (i.e., 570 ppm) in open top chambers, ambient CO2 (i.e., 370 ppm)in open top chambers and ambient C~ (i.e., 370 ppm) under open field conditions. Theexperiment was conducted over a period of 161 days.The total dry weight was higher under elevated C~ as compared to ambient C02 in all speciesexcept Chloroxylon swietenia. The response was highest in Swietenia macrophylla and thehighest mean total dry weight was in the elevated C~ treatment. The mean root dry weight, meanleaf dry weight and mean stem dry weight were significantly higher under elevated CO2 ascompared to the ambient. The height increment during the experimental period was highest inChloroxylon swietenia under elevated C02. The girth increment during this period was highest inSwietenia macrophylla and it was observed in the elevated CO2 treatment. When averaged acrossall species, the mean relative growth rates and absolute growth rates were higher under elevatedCO2 than under ambient. When individual species were considered, only Chloroxylon swieteniashowed a slight decrease in absolute and relative growth rates under elevated C02 while the othersshows an increase. Net photosynthetic rate (Pn) was higher in the elevated CO2 treatment inArtocarpus heterophyllus, Swietenia mahogany and Tectona grandis. But a slight decrease of Pnwas observed in Swietenia macrophylla under elevated C02 in comparison to ambient C02. Leafwater potential was higher in all five species under elevated C02 and the highest response toelevated C~ was observed in Chloroxylon swietenia. The stomatal diffusive resistance washighest in Tectona grandis and the value was 16.86 s em". The lowest was observed inChloroxylon swietenia and the value was 2.87 s em", 'The lowest diffusive resistance wasobserved in the elevated CO2 treatment. The transpiration rate was highest in Chloroxylonswietenia and the value was 12.71~g cm,2 S'l. The lowest was observed in Artocarpusheterophyllus and there was no significant difference among the three treatments. The mean leaftemperature was highest in Artocarpus heterophyllus and the lowest leaf temperature was found inChloroxylon swietenia.Based on the above results, it can be concluded that elevated C(h increases growth of a majority oftree species tested. This could have favourable implications for both natural and plantationforestry in Sri Lanka. Results of the present study showed that the capacity of forests for carbonsequestration would be higher in a future climate with higher atmospheric C02 levels.

The effects of shading on dioecious, pistillate Hydrilla verticillata (L.f.) Royle transplants from Lake Okeechobee, Florida, U.S.A.

The effect of shading on morphometric and meristic characteristics of dioecious, pistillate Hydrilla verticillata (L.f.) Royle was investigated in a large outdoor tank using water, sediment, and plants from Lake Okeechobee, Florida. These data were needed for a hydrologically integrated submersed aquatic vegetation model being developed to assess the effects of restoration activities on Lake Okeechobee. Plants were grown in peat sediment and lake water, under ambient temperature (27.0-30.8 °C) and photoperiod (13 L: 11D to 14 L: 10 D). Treatments were established by differentially shading plants with varying numbers of layers of fiberglass window screen. Photon flux density (PFD) measured 0.27 m above the sediment surface ranged from 8 to 154 μmole photons m -2 s -1 , or 1.1 to 21.6 % of average incident photosynthetically active solar radiation (PAR), based on percent transmittance in the tank and averaged continuous daytime measurements from a mid-lake PAR sensor. Plant characteristics examined included ash-free dry mass (AFDM), leaf, node, shoot, and branch numbers, leaf area, cumulative shoot length, and the number of leaves on the upper third of all shoots; all of which decreased linearly with decreasing PAR, and had statistically significant treatment effects. No statistically significant treatment effects were found for maximum shoot and mean and maximum internodal lengths, or when the number of leaves or branches on the upper third of all shoots were expressed as a percentage of their totals, indicating that significant treatment-induced internodal elongation and canopy formation had not occurred. Mean absolute and relative growth rates ofH. verticillata were estimated to be 11.6 ± 1.9 mg AFDM plant -1 d -1 (mean ± SE) and 0.04 ± 0.003 d -1 , respectively. Estimated photosynthetic PFDs for no net growth (NNG) was negative, with an upper 95 % confidence limit of 13 μmole photons m -2 s -1 , or 1.8 % of mean incident PAR for absolute, and 7 μmole photons m -2 s -1 , or 0.9 % of mean incident PAR for the mean relative growth rate. These results demonstrate that H. verticillata has a high growth rate and can grow in very low light, which may impart an important adaptive advantage given the poor light climate typical of much of Lake Okeechobee and many other disturbed, culturally hypereutrophic waterbodies.

Production of mummichog (Fundulus heteroclitus): Response in marshes treated for common reed (Phragmites australis) removal

The invasion of U.S. east coast salt marshes by common reed (Phragmites australis) and the efforts to remove it and restore marshes to their natural vegetation (Spartina spp.) can directly impact mummichog (Fundulus heteroclitus) as this abundant species is critically linked to marsh habitat. We estimated population density, growth, and biomass to determine production of mummichog in treated Phragmites (''Treated,'' now dominated by Spartina), untreated Phragmites, and naturally occurring Spartina habitats in Delaware Bay using throw traps for small fish (mean 5 24.1 mm standard length or SL, 95% CI 5 10-38) and tag/recapture for large fish (mean 5 36.5 mm SL, 95% CI 5 18-64). Mean population density of small fish on the marsh surface was significantly higher in the Spartina (20.2 fish m 22 ) and Treated (14.1 fish m 22 ) habitats than in the Phragmites (0 fish m 22 ) habitat. Population density of large fish was similar among all three habitats (mean 5 0.9-1.7 fish m 22 ). Mean absolute growth rates of large fish were significantly higher in the Spartina (0.24 mm d 21 ) and Treated (0.24 mm d 21 ) habitats than in the Phragmites (0.13 mm d 21 ) habitat. Mean monthly mummichog production during June to September varied among habitats with Spartina highest (1.22 g dw m 22 mo 21 ), Treated intermediate (0.51 g dw m 22 mo 21 ), and Phragmites lowest (0.07 g dw m 22 mo 21 ). Small fish were the largest contributor to the production estimates in Spartina and Treated habitats. The Phragmites habitat had little or no standing water at low tide (i.e., optimal habitat for small fish was lacking), and thus, it had the lowest production for mummichog. These results also indicated that Treated marshes were more similar to Spartina than to Phragmites habitat; therefore, it appears that habitat quality and mummichog production can be increased with restoration.

Sublocalization and Volumetric Growth Pattern of Intracanalicular Vestibular Schwannomas

None of several previous reports on the growth pattern of vestibular schwannomas (VS) have dealt with the sublocalization and volumetric growth pattern of intracanalicular tumors. This paper reports such data from 196 patients. All VS patients have been registered prospectively at one center in Denmark since 1975. Data on intracanalicular tumors were drawn from the database, yielding 196 patients with a diagnostic and at least one control magnetic resonance imaging scan. All images were retrieved and the tumor sublocalization, size, and growth rate determined. The majority (50%) of the tumors was located centrally in the internal auditory canal (IAC), whereas 31% were porus-near and 19% fundus-near. Of the 196 tumors, 88 (45%) displayed growth, 20 (10%) shrinkage, and 88 (45%) remained unchanged. Thirty-eight (19%) tumors grew to extrameatal extension. Growth occurred only within 5 years after diagnosis. In the 88 growing tumors, the mean absolute growth rate was 111mm/year and the relative rate 114%/volume/year. The occurrence of IAC expansion at diagnosis was higher for tumors displaying subsequent shrinkage. Growth occurrence and rate, IAC expansion, and progression to extrameatal extension were not related to tumor sublocalization. Most intracanalicular VS are located centrally in a nonexpanded IAC at diagnosis. Growth occurs within 5 years after diagnosis in up to 45% of the tumors, although only 19% extend into the cerebellopontine angle. IAC expansion, growth occurrence, and rate are not related to tumor sublocalization. These findings justify primary observation of all purely intracanalicular tumors, unless realistic hearing preservation is intended.

Volumetric analysis of the growth rate of incompletely resected intracranial meningiomas

Objective Intracranial meningiomas are mostly considered to be slow growing tumors. However, only a few previous reports provide information on the growth rate of these tumors. The aim of this study was to determine the growth rates of intracranial meningiomas after subtotal resection, analysing their relation to radiological appearance and histological features. Results are compared with our previous analysis of growth rates in incidental meningiomas. Methods The hospital charts, follow up records and imaging studies were reviewed in 36 patients with subtotally resected intracranial meningiomas. The tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. Results In the group of 33 patients with histologically verified grade 1 meningiomas, the mean absolute growth rate was 1.51 cm3/year, the median relative growth rate and tumor doubling time was 14.18%/year and 5.228 years. In young patients annual relative growth rates were significantly higher. The median annual relative growth rate of meningiomas with calcification was significantly lower than in tumors without calcification. Also tumors with hypo — or isointense T2-signals on MRI revealed a lower growth rate. There was no significant difference between males and females. Histological studies revealed 22 meningiomas of a meningotheliomatous subtype, 8 fibrous and 3 psammomatous meningiomas. The comparison of growth rates between these subtypes did not show any significant differences. In atypical meningiomas (WHO grade 2), absolute and relative growth rates were significantly higher and tumor doubling times shorter. Conclusion The majority of intracranial meningiomas are slow growing tumors, although the growth rates may vary widely even among benign grade 1 meningiomas. In meningiomas after subtotal surgical resection, the age of the patients seems to present a predictive factor for tumor growth in analogy to our previous observation in incidental meningiomas. Significantly higher relative growth rates were detected in younger patients. Gender does not seem to play a major role as a predictive factor. Radiological features such as calcification or T2-signal intensity may provide additional information to predict the growth potential of meningiomas. Close clinical and radiological observation should be performed in young patients harboring tumors with absence of calcification or high T2-signal intensities due to the higher growth potential in this patient group.

Larval growth and mortality of japanese spanish mackerel (scomberomorus niphonius) in the central seto inland sea, japan

growth and mortality rates of larval japanese spanish mackerel (scomberomorus niphonius) were estimated by using otolith daily increments in 1997 and 1998 in the sea of hiuchi, central seto inland sea. there was no day–night difference in the abundance and size-distribution of s. niphonius larvae in the 3–10 mm size-classes, indicating the larvae were efficiently collected by the larva-net used for sampling (1.3 m mouth diameter, 0.5 mm mesh). mean absolute growth rate (0.748 mm d−1 in 1997, 0.821 mm d−1 in 1998), weight specific growth coefficient (g: 0.402 in 1997, 0.444 in 1998) and mortality coefficient (m: 0.784 in 1997 and 0.625 in 1998) were among the highest reported for marine fish larvae. scomberomorus niphonius seems to have evolved survival strategies characterized by fast growth with strong piscivory that can reduce duration of the larval period with the high mortality. in 1997, spatial distribution of the larvae was not well corresponded to that of their prey, clupeid larvae, and the larval feeding incidence was lower than in 1998. recruitment potential assessed by examining the ratio of g:m was lower in 1997 (0.513 in 1997, 0.711 in 1998) due to the lower g and higher m values. prey fish availability may be one of the important determinants for the recruitment potential by controlling the larval mortality due to starvation and/or starvation-related predation.

Volumetric Analysis of the Growth Rate of Incompletely Resected Intracranial Meningiomas

Intracranial meningiomas are mostly considered to be slow growing tumors. However, only a few previous reports provide information on the growth rate of these tumors. The aim of this study was to determine the growth rates of intracranial meningiomas after subtotal resection, analysing their relation to radiological appearance and histological features. Results are compared with our previous analysis of growth rates in incidental meningiomas . The hospital charts, follow up records and imaging studies were reviewed in 36 patients with subtotally resected intracranial meningiomas. The tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. In the group of 33 patients with histologically verified grade 1 meningiomas, the mean absolute growth rate was 1.51 cm (3)/year, the median relative growth rate and tumor doubling time was 14.18 %/year and 5.228 years. In young patients annual relative growth rates were significantly higher. The median annual relative growth rate of meningiomas with calcification was significantly lower than in tumors without calcification. Also tumors with hypo- or isointense T (2)-signals on MRI revealed a lower growth rate. There was no significant difference between males and females. Histological studies revealed 22 meningiomas of a meningotheliomatous subtype, 8 fibrous and 3 psammomatous meningiomas. The comparison of growth rates between these subtypes did not show any significant differences. In atypical meningiomas (WHO grade 2), absolute and relative growth rates were significantly higher and tumor doubling times shorter. The majority of intracranial meningiomas are slow growing tumors, although the growth rates may vary widely even among benign grade 1 meningiomas. In meningiomas after subtotal surgical resection, the age of the patients seems to present a predictive factor for tumor growth in analogy to our previous observation in incidental meningiomas. Significantly higher relative growth rates were detected in younger patients. Gender does not seem to play a major role as a predictive factor. Radiological features such as calcification or T (2)-signal intensity may provide additional information to predict the growth potential of meningiomas. Close clinical and radiological observation should be performed in young patients harboring tumors with absence of calcification or high T (2)-signal intensities due to the higher growth potential in this patient group.

Hatchery Performance Attributes of Juvenile Lake Sturgeon Fed Two Natural Food Types

AbstractThe use of stocking programs to rehabilitate depressed populations of lake sturgeon Acipenser fulvescens requires the optimization of early life stage growth in hatchery settings. We evaluated the performance of juvenile lake sturgeon fed different proportions of two natural food types—adult brine shrimp Artemia spp. and larval bloodworms Chironomus spp.—over a 10‐week laboratory experiment. The following five diet treatments were provided: (1) 100% bloodworms; (2) 75% bloodworms : 25% brine shrimp; (3) 50% bloodworms : 50% brine shrimp; (4) 25% bloodworms : 75% brine shrimp; and (5) 100% brine shrimp. Lake sturgeon growth was positively related to bloodworm content in the diet and was significantly different among treatments. Although the initial sizes of fish were similar, mean fork length and wet weight were greatest for the 100% bloodworm treatment (183.1 mm and 37.5 g, respectively) and lowest for the 100% brine shrimp diet (118.4 mm and 9.5 g) by the end of the study. Mean specific and absolute growth rates in length (0.93% and 1.28 mm/d, respectively) and weight (2.61% and 0.45 g/d) were greatest for the 100% bloodworm diet, followed by the other treatments in order of decreasing amount of bloodworms in the diet. Percent weight gain (525%) and food conversion efficiency (67%) were also greatest for the 100% bloodworm diet, followed by the other treatments in order of decreasing dietary bloodworm content. Whole‐body protein (13.9%), lipid (2.5%), and gross‐energy (3.77 kJ/g) content were greatest for fish fed 100% bloodworms, with these proximate‐composition measures also ranked in order of decreasing dietary bloodworm content for the other treatments. We recommend that juvenile lake sturgeon reared in hatchery environments be fed high proportions of bloodworms to maximize growth, body size, and lipid content for rehabilitation stocking programs.

Phenology and growth response to irrigation and sowing date of Kabuli chickpea (Cicer arietinum L.) in a cool-temperate subhumid climate

The photothermal response of three Kabuli chickpea (Cicer arietinum L.) cultivars, at different growth stages, to eight irrigation treatments in 1998/99 and four irrigation treatments in 1999/2000 was studied on a Wakanui silt loam soil in Canterbury, New Zealand (43°38S, 172°30E). The rate of development from emergence to flowering (e-f) and sowing to harvest maturity were strongly and positively associated (R2=0·87, P&lt;0·001) with mean temperature during those periods. All phenological stages considered (sowing to emergence, e-f, flowering to podding, podding to physiological maturity and physiological maturity to harvest maturity) depended upon accumulated thermal time (Tt) above a base temperature (Tb) of 1 °C.An accurate prediction of time of flowering was made based on an accumulated mean Tt requirement of 629 °Cdays from e-f (R2=0·91, P&lt;0·001). Fully irrigated crops had higher maximum dry matter accumulation (maxDM; 1093 g/m2), duration of exponential growth (DUR; 99 days), weighted mean absolute growth rate (WMAGR; 12·2 g/m2 per day) and maximum crop growth rate (MGR; 17·1 g/m2 per day). In 1998/99 the positive response of maxDM and MGR depended on a significant (P&lt;0·01) interaction between irrigation and sowing date. The maxDM during the season was highly correlated with DUR and MGR (R2=0·79 and 0·65). It is concluded that to maximize chickpea biological yield in the dry season of the cool-temperate subhumid climate of Canterbury, irrigation should extend across all phenological stages.

Variation in Individual Growth and the Population Structure of a Woodland Perennial Herb, Paris Tetraphylla

Year-to-year growth dynamics of a long-lived woodland perennial herb, Paris tetraphylla, were investigated based on the diffusion model. The past biomass growth of each harvested individual was traced back by measuring the rhizome volume between stem scars. The population density was 2.47 m −2 . Interference between individuals was therefore expected to be almost absent. Two-year field observations revealed that there was little mortality and only a few recruits by seed. Branching of rhizomes (vegetative reproduction or clonal growth) was also very rare. Mean absolute growth rate per year of individuals of biomass x at year t (defined as the G(t,x) function representing averaged species characteristics) was nearly 0 irrespective of x and t, whilst variance of absolute growth rates per year of individuals of biomass x at year t (defined as the D(t,x) function which is caused by environmental fluctuations, genetic variation, etc.) was proportional to x b where b ranged between 1 and 2 (...)

Variations in the age and growth of yellowfin tuna larvae,Thunnus albacares, collected about the Mississippi River plume

Eight hundred and one yellowfin tuna larvae ranging from 2.57–7.48 mm SL were collected near the Mississippi River discharge plume in the Gulf of Mexico during July and September, 1987. Larvae were most abundant at intermediate salinities (i.e. frontal waters) where chlorophylla and macrozooplankton displacement values were also highest. Using sagittal otolith microstructure, we estimated larval ages ranging from 3–14 d. These ages were used to back calculate spawning dates from 13–24 July and 22–31 August. Mean absolute individual growth rate (length age−1) was 0.47 mm d−1, with the least squares linear regression SL = 1.67 + 0.47 AGE (r2 = 0.60, Pr> F = 0.0001) representing the best growth curve. Highest growth occurred at intermediate salinities near 31%, and temperatures near 29° C. There was significant temporal variation in growth, with larvae collected in July growing slower than those from September (0.37 and 0.48 mm d−1, respectively). The pooled instantaneous daily mortality rate (Z) of the larvae was estimated to be 0.33 d−1 (0.16 d−1 in July and 0.41 d−1 in September). These results show that significant spawning of yellowfin tuna may occur in the northern Gulf of Mexico in the vicinity of the Mississippi River discharge plume, and suggest that larval growth and survival may be enhanced in the plume frontal waters.

FIELD GROWTH ANALYSIS OF WATERMELON PLANTS UNDER VARIOUS ROWCOVERS AND MULCHES

`Crimson Sweet' watermelon plants grown under various mulches and rowcovers were harvested weekly and analyzed for absolute growth rate (AGR), relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA), specific leaf weight (SLW), leaf weight ratio (LWR), leaf area duration (LAD), biomass duration (BMD), and runner growth. Hourly air and soil temperatures were monitored inside the rowcovers. Vispore and Reemay rowcovers generally showed greater mean AGR, LAR, SLA, LAD, and BMD than Agronet black-clear and black mulches. No significant differences in LWR were found between mulched and rowcovered plants. Plants under mulches and rowcovers showed significant increases in AGR, RGR, NAR, LAR, SLA, LAD, and BMD over noncovered (bare ground) plants. Longest runner length was highly correlated with total runner length. Growth analyses depicted decreased growth rate inside the rowcovers during the hottest weeks of the summer, and generally correlated well with the earliness and total yield of the crop.