Age,growth and length–weight relationships of Pinna bicolor Gmelin (Bivalvia: Pinnidae) in the seagrass beds of Sungai Pulai Estuary,Johor, Peninsular Malaysia

Age and growth of Pinna bicolor were examined in the seagrass beds of Merambong shoal (N 1°19′55.62″; E 103°35′57.75″) off the south‐western coast of Johor, Peninsular Malaysia between May 2006 and April 2007. Monthly growth increment data of P. bicolor were analyzed using FiSAT software (FAO‐ICLARM Stock Assessment Tools) to estimate the asymptotic length (L_∞) and growth coefficient (K). Average growth rate of P. bicolor was 1.42 (±0.01) cm per month; the estimated asymptotic length (L_∞) and growth coefficient (K) were 34.66 cm and 0.88 per year, respectively. In their natural habitat, P. bicolor attain shell heights of approximately 17, 25 and 30 cm at the end of their first, second and third years of growth. The length–weight relationship was estimated as Log W = ?5.397 + 3.111Log L, and in exponential form the equation was W = 0.000004L^3.111 (r² = 0.99, P < 0.01). Habitat temperature and salinity ranged between 27.47 and 29.66°C and 28.66–33.00 ppt with a mean of 29.10 (±0.66) m°C and 30.52 (±1.41) ppt, respectively.     

Length–weight relationships of three fish species from a tropical mangrove estuary of Sarawak,Malaysia

Length–weight relationships for three mangrove fish species, Setipinna melanochir (Bleeker, 1849), Ilisha elongata (Anonymous [Bennett], 1830), and Nibea soldado (Lacépède, 1802) were determined. Samplings were conducted in a tropical mangrove estuary, Sarawak, Malaysia (3°59′25.76′′N; 113°43′51.6′′E) at the peak of three different seasons using gillnets (100 × 2.5 m, mesh sizes 1, 2 and 4 inches) during 2014–2015. No information regarding length–weight relationships of these species was reported previously in FishBase.     

Age and growth in pink cusk-eel (Genypterus blacodes) off the Chilean austral zone: evaluating differences between management fishing zones

The von Bertalanffy (vB) growth parameters for pink cusk‐eel (Genypterus blacodes) were estimated for the Chilean austral‐zone (41°28′–57°00′S) by gender and management fishing zones. A total of 47 026 samples were collected between March 1982 and May 2004, with total length ranging from 19 to 154 cm. Age determinations, based on the reading of saggital otoliths, were between 1 and 14 years in males and between 1 and 16 years in females. Statistical differences in growth were found between the sexes and management fishing zones. For the combined sexes the vB growth parameters for the northern‐austral zone (41°28′–47°00′S) were: l_∞=111.452 cm, k = 0.186 year⁻¹, t₀ = −0.912 year; and for the southern‐austral zone (47°00′–57°00′S): l_∞ = 123.447 cm, k = 0.147 year⁻¹, t₀ = −1.779 year.     

Latitudinal and altitudinal growth patterns of brown trout Salmo trutta at different spatial scales

Spatial variation in growth of stream‐dwelling brown trout Salmo trutta was explored in 13 populations using a long‐term study (1993–2004) in the Bay of Biscay drainage, northern Spain. The high variability in fork length (L_F) of S. trutta in the study area was similar to the body‐size range found in the entire European distribution of the species. Mean L_F at age varied: 0+ years, 57·4–100·7 mm; 1+ years, 111·6–176·0 mm; 2+ years, 155·6–248·4 mm and 3+ years, 194·3–290·9 mm. Average L_F at age was higher in main courses and lower reaches compared with small tributaries and upper reaches. Annual specific growth rates (G_L) were: 0+ to 1+ years, 0·634–0·825 mm mm⁻¹ year⁻¹; 1+ to 2+ years, 0·243–0·342 mm mm⁻¹ year⁻¹; 2+ to 3+ years, 0·166–0·222 mm mm⁻¹ year⁻¹, showing a great homogeneity. Regression models showed that water temperature and altitude were the major determinants of L_F at age variability within the study area. A broader spatial analysis using available data from stream‐dwelling S. trutta populations throughout Europe indicated a negative relationship between latitude and L_F of individuals and a negative interaction between latitude and altitude. These findings support previous evidence of the pervasive role of water temperature on the L_F of this species. Altitude appeared as the overall factor that includes the local variation of other variables, such as water temperature or food availability. At a larger scale, latitude was the factor that encompassed these environmental gradients and explained the differences in L_F of S. trutta. In summary, L_F at age in stream‐dwelling S. trutta decreases with latitude in Europe, the converse of Bergmann's rule.     

Maturity and growth of Paralonchurus brasiliensis females in southern Brazil (Teleostei, Perciformes, Sciaenidae)

Samples of Paralonchurus brasiliensis Steindachner, 1875 (627 females; no males) were taken monthly from June 1997 to May 1998 at the fishing pier of Cidreira – Rio Grande do Sul (30°08′S; 50°11′W) in southern Brazil. The fish were captured by sport fishermen using different sizes of hook‐and‐line. The reproductive period of P. brasiliensis extends from August to March, presenting greater activity from October to February. Females reach first maturation at 15.4 cm total length (TL). Of the 466 scales analyzed, one to six annuli were found. Growth annuli are formed between June and August, corresponding to the winter period (southern hemisphere), with the first visible annulus being formed when the fish are 1.5 years old. The length growth curve for P. brasiliensis females is described as: L_t = 20.0 (1 ? e^?0.564×t), TL in centimeters and age in years. The undersize asymptotic length may be a result of excessive fishing mortality on the studied population.     

On the biological characteristics of Capoeta fusca Nikolskii, 1897 in eastern Iran

It is hypothesized that Capoeta fusca might display specific life‐history traits that differ from other species of this genus. To test this hypothesis a total of 354 specimens of C. fusca (listed by ICUN in the category DD = data deficient) were caught in the Qanat of Shadmehr (a well‐known active man‐made water well system in eastern Iran) on a monthly basis to cover fully the reproductive season from April to October 2007. Based on opercula readings the maximum ages of the population were 5+ years for both sexes. Sizes ranged from 57 to 190 mm total length (weight 2.14–84.76 g). Length‐weight relationship implied that the growth was negatively allometric for males and isometric for females. The von Bertalanffy growth model was estimated as L_t=18.74(1‐e^{?0.33(t+0.473)}) and L_t=22.35(1‐e^{?0.32(t+0.333)}) for males and females, respectively. Sex ratio was 1 : 2.42 in favour of females. The GSI indicated that reproduction of the fish in the qanat system occurred between May and August, with the highest average value of 6.12 for males in June and 9.55 for females in July. Oocyte diameters ranged from 0.30 to 2.05 mm, with a mean value of 0.92 mm. Absolute fecundity ranged between 506 and 22 800 eggs, with a mean of 4961 eggs. Fecundity relative to total weight fluctuated from 34 to 583, with a mean value of 133 eggs per g. Absolute fecundity and oocyte diameter to fish size (length and weight) were significantly correlated.     

Age, growth, and sexual maturity of the yellownose skate Dipturus chilensis in the south‐eastern Pacific

The age and growth parameters of Dipturus chilensis were estimated by counting growth rings from thin sections of vertebral centra from 400 fish (246 females and 154 males), ranging from 23 to 124 cm total length (L_T), and backcalculating fish lengths at previous ages. Marginal increment analysis lent support to the hypothesis of annual deposition of band‐pairs, which formed during the winter months. The oldest female D. chilensis aged in this study was 21 years and 117 cm L_T, whereas the oldest male was 18 years and 93 cm L_T. A 4·7% index of average per cent error (I_APE) suggested that this is a precise method for calculating the age of D. chilensis. Observed L_T were lower than backcalculated L_T, which implies the influence of Lee's phenomenon. The von Bertalanffy growth equations, based on mean length‐at‐age data, were estimated as L_t = 128·3 (1 ? e^{?0·112 (t + 0·514)}) for females and L_t = 107·8 (1 ? e^{?0·134 (t + 0·862)}) for males where t is age (years). Growth was significantly different between sexes: females reached a larger adult size. Ages and lengths at 50% maturity were estimated at 14 years of age and 106 cm L_T for females and 11 years of age and 86 cm L_T for males. At c. 14 years, there was a decline in growth rates in females. The factor most likely responsible for this was sexual maturity, which caused a discontinuity in growth of female fish. These results show that this species is slow‐growing, long‐lived, relatively large and of delayed maturity, characteristics that make it vulnerable to exploitation.     

Validated age,growth and maturity of the bonnethead Sphyrna tiburo in the western North Atlantic Ocean

The age, growth and maturity of bonnetheads Sphyrna tiburo inhabiting the estuarine and coastal waters of the western North Atlantic Ocean (WNA) from Onslow Bay, North Carolina, south to West Palm Beach, Florida, were examined. Vertebrae were collected and aged from 329 females and 217 males ranging in size from 262 to 1043 mm and 245 to 825 mm fork length, L_F, respectively. Sex‐specific von Bertalanffy growth curves were fitted to length‐at‐age data. Female von Bertalanffy parameters were L_∞ = 1036 mm L_F, k = 0·18, t₀ = ?1·64 and L₀ = 272 mm L_F. Males reached a smaller theoretical asymptotic length and had a higher growth coefficient (L_∞ = 782 mm L_F, k = 0·29, t₀ = ?1·43 and L₀ = 266 mm L_F). Maximum observed age was 17·9 years for females and 16·0 years for males. Annual deposition of growth increments was verified by marginal increment analysis and validated for age classes 2·5+ to 10·5+ years through recapture of 13 oxytetracycline‐injected specimens at liberty in the wild for 1–4 years. Length (L_F50) and age (A₅₀) at 50% maturity were 819 mm and 6·7 years for females, and 618 mm and 3·9 years for males. Both female and male S. tiburo in the WNA had a significantly higher maximum observed age, L_F50, A₅₀ and L_∞, and a significantly lower k and estimated L₀ than evident in the Gulf of Mexico (GOM). These significant differences in life‐history parameters, as well as evidence from tagging and genetic studies, suggest that S. tiburo in the WNA and GOM should be considered separate stocks.     

Age, growth and reproductive characteristics of chub, Leuciscus cephalus (L., 1758) in the İkizcetepeler dam lake (Balikesir), Turkey

In this study, the population structure, growth and reproduction characteristics of 414 chub (Leuciscus cephalus L., 1758) from the ?kizcetepeler dam lake were investigated monthly between January and December 2000. Age groups ranged between I and VI for this species in the reservoir, with the second and third year‐classes dominating. Sex ratio was 1 : 1.4 (M : F), corresponding to 58.4% males and 41.6% females. Females attained greater size and age than males. The largest female captured was 24.8 cm FL, the largest male was 24.1 cm FL, both age VI. The von Bertalanffy growth equations and length–weight relationships were found as: L_t = 28.89[1 ?e^{?0.224(t+1.55)}] for females, L_t = 26.71[1 ? e^{?0.259(t+1.55)}] for males; W_t = 347.386[1?e^{?0.224h (t+1.55)}]^2.86 for females, W_t =286.48[1?e^{?0.259 (t+1.55)}]^2.92 for males; W = 0.0227 × L^2.87 for females and W = 0.0194 × L^2.92 for males. Significant statistical differences in condition factors between age classes and sexes were not found (P > 0.05, t‐test). Spawning period of this species in the lake was between April and May.     

Reproductive biology of the electric lanternfish Electrona risso (Myctophidae) and the bigscale fishes Melamphaes polylepis and Scopelogadus mizolepis (Melamphaidae)

This study was the first to investigate the key reproductive traits of the electric lantern fish Electrona risso (Myctophidae, n = 918) and the bigscale fishes (Melamphaidae) Melamphaes polylepis (n = 260) and Scopelogadus mizolepis (n = 649). Specimens of these mesopelagic species were collected in March and April 2015 in the eastern Central Atlantic (0–24° N, 20–26° W). Sex ratio was not significantly different from 1:1 in E. risso and M. polylepis but significantly skewed toward female dominance in S. mizolepis. Reproductive phases were determined macroscopically and by histological analyses on selected individuals. Female length at 50% maturity (L₅₀) was 55.1 mm standard length (L_S) in E. risso, with an observed female maximum length (L_max) of 81.2 mm L_S. M. polylepis females had an L₅₀ of 40.2 mm L_S and an L_max of 86.7 mm L_S. S. mizolepis had an L₅₀ of 46 mm L_S and an L_max of 97.9 mm L_S. The three species show histological features of iteroparity, but the E. risso population appears to occur in two year-classes and experience only one spawning season per lifetime in the study region. All three species are batch-spawners. A batch fecundity of 2668 eggs was estimated from one E. risso individual, with a relative batch fecundity of 369 eggs g⁻¹ gonad-free body mass. M. polylepis had a batch fecundity of 1027 eggs and a relative batch fecundity of 149 eggs g⁻¹ (n = 3). S. polylepis had a batch fecundity of 1545 eggs and a relative batch fecundity of 215 eggs g⁻¹ (n = 21). The median gonado-somatic index during the actively spawning phase of E. risso was 4.5, significantly lower than that of M. polylepis (7.5) and S. mizolepis (7.1). No regressing or regenerating phases were observed in this study. Batch-spawning in all three species is suggested to be advantageous to cope with intra-annual variability in food supply and other risks for offspring survival. With what appears to be in effect a (facultative) semelparous strategy in combination with a short life span in E. risso, interannual differences would have a great effect on population dynamics of this species. Knowledge is still lacking on temporal aspects of reproduction such as the duration of the spawning season and the frequency of spawning, as well as age and growth.     

Life‐history strategies of the rock hind grouper Epinephelus adscensionis at Ascension Island

Epinephelus adscensionis sampled from Ascension Island, South Atlantic Ocean, exhibits distinct life‐history traits, including larger maximum size and size at sexual maturity than previous studies have demonstrated for this species in other locations. Otolith analysis yielded a maximum estimated age of 25 years, with calculated von Bertalanffy growth parameters of: L_∞ = 55·14, K = 0·19, t₀ = ?0·88. Monthly gonad staging and analysis of gonad‐somatic index (I_G) provide evidence for spawning from July to November with an I_G peak in August (austral winter), during which time somatic growth is also suppressed. Observed patterns of sexual development were supportive of protogyny, although further work is needed to confirm this. Mean size at sexual maturity for females was 28·9 cm total length (L_T; 95% C.I. 27·1–30·7 cm) and no females were found >12 years and 48·0 cm L_T, whereas all confirmed males sampled were mature, >35·1 cm L_T with an age range from 3 to 18 years. The modelled size at which 50% of individuals were male was 41·8 cm (95% C.I. 40·4–43·2 cm). As far as is known, this study represents the first comprehensive investigation into the growth and reproduction of E. adscensionis at its type locality of Ascension Island and suggests that the population may be affected less by fisheries than elsewhere in its range. Nevertheless, improved regulation of the recreational fishery and sustained monitoring of abundance, length frequencies and life‐history parameters are needed to inform long‐term management measures, which could include the creation of marine reserves, size or temporal catch limits and stricter export controls.     

Reproductive biology of the guitarfish Rhinobatos percellens (Chondrichthyes,Rhinobatidae) from the São Paulo Coast,Brazil, western South Atlantic Ocean

The reproductive biology of the guitarfish Rhinobatos percellens was studied from 751 specimens caught by bottom pair trawlers off the coast of São Paulo, Brazil, between c. 24° 00′ S; 45° 15′ W and c. 25° 10′ S; 47° 52′ W, from September 2007 to August 2009. The total length (L_T) and total mass (M_T) relationship for males and females combined was M_T = 1·29E‐06 L_T^3·15 (r = 0·99, n = 751). The mean L_T of sexually mature specimens was 548 mm for males and 583 mm for females. Clasper growth was allometric and showed three distinct phases. Most claspers were calcified in specimens of c. 550 mm L_T. The mean diameter of the largest oocyte was 29·8 mm, the mean ovarian fecundity was seven oocytes and ovulation occurred between August and November. Uterine fecundity ranged from two to 13 embryos (mean of five embryos). Larger females had higher litter sizes and larger embryos; the size‐at‐birth was c. 200 mm L_T. The hepato‐somatic index oscillated seasonally for males and females; the gonado‐somatic index had little variation in males, but varied seasonally in females. The presence of many non‐pregnant adult females and of encapsulated eggs during two consecutive seasons suggests a resting period between gestations and the possibility of diapause.     

Temporal patterns of growth in larval cohorts of the Japanese sardine Sardinops melanostictus in a coastal nursery area

Growth patterns of larval sardine Sardinops melanostictus were studied in a coastal nursery area, in southern Japan for four monthly hatch cohorts of larvae (November, December, January and February) for the 2003–2004 and 2004–2005 seasons. Laird–Gompertz models were fitted to each cohort using both total length (L_T)‐at‐age at capture and mean L_T‐at‐age data derived from backcalculations. In both approaches, the absolute daily growth rates (G_R) and absolute daily growth rates at the inflection point (G_XO) were estimated. In parallel, individual growth rates (G_I) were derived from backcalculated L_T (L_B). Growth showed the following general common patterns irrespective of hatch month, season and methods: (1) significant Laird–Gompertz fits, (2) asymptotic growth, (3) a decrease in G_R after the inflexion point, except for February for the 2003–2004 season that showed an apparent constant growth pattern, (4) six in eight cohorts showed G_XO ranging from 0·8 to 1·2 mm day^?1 and (5) a decreasing tendency of G_I from 1·75 to 0·24 mm day^?1, from first feeding through the first month of larval life. The contrasting pattern between the 2003–2004 and the 2004–2005 seasons were: (1) allometric v. logarithmic (ln) L_T and otolith radius relationships, (2) low G_XOv. high G_XO, (3) high G_Rv. low G_R when growth turned asymptotic, (4) low G_XOv. high G_XO when monthly hatch cohorts were combined and (5) L_B and G_I not differing among monthly hatch cohorts. The differences in growth patterns and growth rates between seasons seemed to be linked to the influx of warmer and oligotrophic waters of the Kuroshio Current that triggered an increase of 3° C in the coastal area for the 2003–2004 seasons. In the overall context, however, the high G_XO, within cohorts and seasons reported in the current study, suggests that either sea surface temperature (SST) or food availability, or both are in the optimal range of preferences for S. melanostictus larvae. Consequently, nearshore coastal areas seem to be playing an important role as a nursery area for the larval stage of this species.     

Growth and length–weight relationship of the juvenile anchovy, Engraulis encrasicolus, in the nursery ground (Zrmanja River estuary–eastern Adriatic Sea)

Growth and length–weight relationships of 2564 juvenile specimens of anchovy, Engraulis encrasicolus (Linnaeus, 1758), were examined over a 2‐year period (August 1989 to April 1991) in the Zrmanja River estuary. Fish sizes ranged from 4.4 to 12.5 cm total length and 0.5 and 13.8 g, corresponding to age (in years) 0+ (98%) and 1+ (2%). Length–weight regression coefficient (b) varied between 2.95 and 3.42 and the regression constant (a) between 2.1 and 6.0 (×10^?3). The von Bertalanffy growth equation of juvenile anchovy was: l_t = 13.2 (1 ? e^?0.82(t+0.5)). Maturity was reached in June in males above 8.2 cm and females above 9.0 cm total length.     

Magnesium methoxide‐induced chemiluminescent decomposition of bicyclic dioxetanes bearing a 2′‐alkoxy‐2‐hydroxy‐1,1′‐binaphthyl‐7‐yl moiety

Bicyclic dioxetanes 2a–c bearing a 2′‐alkoxy‐2‐hydroxy‐1,1′‐binaphthyl‐7‐yl moiety were effectively synthesized and their base‐induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na⁺ and K⁺) or Mg²⁺ alkoxide in MeOH. When 2a–c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λ_max^CL = 573–577 nm) with efficiency Φ^CL = 6–8 × 10^–2. On the other hand, for an alkaline metal (Na⁺ or K⁺) alkoxide/MeOH system, 2a–c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and Φ^CL (= 1.4–2.3 × 10^–3) was considerably decreased. In addition, Mg(OMe)₂ was found to play a characteristic role as a base for the chemiluminescent decomposition of 2a–c through coordination to the intermediary oxidoaryl‐substituted dioxetanes 13. Thus, Mg²⁺ increased Φ^CL to more than twice those with Na⁺ or K⁺, while it shifted λ_max^CL considerably toward blue (λ_max^CL = 550–566 nm). Copyright © 2012 John Wiley & Sons, Ltd.     

Measurement of Cerebral Glucose Utilization Using Washout After Carotid Injection in the Rat

Abstract: The carotid injection technique, used previously to quantitate the kinetics of blood-brain barrier transport of metabolic substrates, may be modified to analyze the rate of cerebral glucose utilization. A 0.2-ml solution of [¹⁴C]glucose (G_F) and [³H]methylglucose (M), an internal reference, is rapidly injected into the carotid artery, followed by microwave fixation of brain at various times up to 4 min after injection. The brain radioactivity is separated into a fraction containing neutral hexoses (G_F and M) and a fraction containing metabolites of glucose. The G_F/M ratio is related to the rate constant (k₃) of brain glucose utilization by the simple, linear equation: In(G_F/M) = In(G_F°/M°) –k₃t, where G_F°/M°= the brain uptake index of glucose, relative to methylglucose, at 5-15 s after injection, and t= the time after carotid injection, e.g., 1–4 min. It is assumed that (a) the rate of influx due to recirculation of label is minimal during the 4-min circulation period; and (b) the rate constants of glucose efflux (k₂) and methylglucose efflux (k₂*) are identical. Independent estimates of k₂ and k₂* showed these parameters to be identical: k₂= 0.14 + 0.08 min-I; k₂*= 0.14 ± 0.02 min-I. A logarithmic plot of G_F/M ratios versus time was linear (r = 0.99), and was described by the slope k₂= 0.21 ± 0.02 min^?1. Assuming glucose is uniformly distributed in brain, then the glycolytic rate = k₃× brain glucose = (0.21 min^?1) (2.6 μmol g^?1) = 0.55 μmol min^?1 g^?1 for the cortex of the barbiturate-anesthetized rat. These studies provide the basis for a simple method of measurement of regional brain glycolysis that does not require either the use of correction factors, e.g., the lumped constant, or the use of differentially labeled glucose.     

Age and growth of Monopterus albus Zuiew, 1793 (Synbranchidae)

Age and growth of Monopterus albus (Zuiew, 1787) in Lake Nanhu, Wuhan, Hubei Province, China, were studied from January to December 2007. A total of 418 samples were collected ranging from 18 to 86 cm total length (TL). Among these samples, ages of female were 1 ⁺ –5 ⁺ years while males were 3 ⁺ –9 ⁺ years as estimated by basihyal. The length–weight relationships and the von Bertalanffy growth curve were described for all individuals as: W_T = (2 × 10^?7) TL^3.2366 and L_t = 104.1{1‐e^{?0.108 (t + 1.625)}}. To the best knowledge of the authors, this study presents the first reference on the relationship between age and growth of this species for the management of fishery resources.     

Allometric growth relationships of East Africa highland bananas (Musa AAA-EAHB) cv. Kisansa and Mbwazirume

Highland bananas are an important staple food in East Africa, but there is little information on their physiology and growth patterns. This makes it difficult to identify opportunities for yield improvement. We studied allometric relationships by evaluating different phenological stages of highland banana growth for use in growth assessment, understanding banana crop physiology and yield prediction. Pared corms of uniform size (cv. Kisansa) were planted in a pest‐free field in Kawanda (central Uganda), supplied with fertilizers and irrigated during dry periods. In addition, tissue‐cultured plants (cv. Kisansa) were planted in an adjacent field and in Ntungamo (southwest Uganda), with various nutrient addition treatments (of N, P, K, Mg, S, Zn, B and Mo). Plant height, girth at base, number of functional leaves and phenological stages were monitored monthly. Destructive sampling allowed derivation of allometric relationships to describe leaf area and biomass distribution in plants throughout the growth cycle. Individual leaf area was estimated as LA (m²) = length (m) × maximum lamina width (m) × 0.68. Total plant leaf area (TLA) was estimated as the product of the measured middle leaf area (MLA) and the number of functional leaves. MLA was estimated as MLA (m²) = ?0.404 + 0.381 height (m) + 0.411 girth (m). A light extinction coefficient (k = 0.7) was estimated from photosynthetically active radiation measurements in a 1.0 m grid over the entire day. The dominant dry matter (DM) sinks changed from leaves at 1118 °C days (47% of DM) and 1518 °C days (46% of DM), to the stem at 2125 °C days (43% of DM) and 3383 °C days (58% of DM), and finally to the bunch at harvest (4326 °C days) with 53% of DM. The allometric relationship between above‐ground biomass (AGB in kg DM) and girth (cm) during the vegetative phase followed a power function, AGB = 0.0001 (girth)^2.35 (R² = 0.99), but followed exponential functions at flowering, AGB = 0.325 e^0.036(girth) (R² = 0.79) and at harvest, AGB = 0.069 e^0.068(girth) (R² = 0.96). Girth at flowering was a good parameter for predicting yields with R² = 0.7 (cv. Mbwazirume) and R² = 0.57 (cv. Kisansa) obtained between actual and predicted bunch weights. This article shows that allometric relationship can be derived and used to assess biomass production and for developing banana growth models, which can help breeders and agronomists to further exploit the crop's potential.     

Size-independent growth in fishes: patterns, models and metrics

A combination of a dynamic energy budget (DEB) model, field data on Atlantic salmon Salmo salar and brown trout Salmo trutta and laboratory data on Atlantic salmon was used to assess the underlying assumptions of three different metrics of growth including specific growth rate (G), standardized mass‐specific growth rate (G_S) and absolute growth rate in length (G_L) in salmonids. Close agreement was found between predictions of the DEB model and the assumptions of linear growth in length and parabolic growth in mass. Field data comparing spring growth rates of age 1+ year and 2+ year Atlantic salmon demonstrated that in all years the larger age 2+ year fish exhibited a significantly lower G, but differences in growth in terms of G_S and G_L depended on the year examined. For brown trout, larger age 2+ year fish also consistently exhibited slower growth rates in terms of G but grew at similar rates as age 1+ year fish in terms of G_S and G_L. Laboratory results revealed that during the age 0+ year (autumn) the divergence in growth between future Atlantic salmon smolts and non‐smolts was similar in terms of all three metrics with smolts displaying higher growth than non‐smolts, however, both G_S and G_L indicated that smolts maintain relatively fast growth into the late autumn where G suggested that both smolts and non‐smolts exhibit a sharp decrease in growth from October to November. During the spring, patterns of growth in length were significantly decoupled from patterns in growth in mass. Smolts maintained relatively fast growth though April in length but not in mass. These results suggest G_S can be a useful alternative to G as a size‐independent measure of growth rate in immature salmonids. In addition, during certain growth stanzas, G_S may be highly correlated with G_L. The decoupling of growth in mass from growth in length over ontogeny, however, may necessitate a combination of metrics to adequately describe variation in growth depending on ontogenetic stage particularly if life histories differ.     

Comparisons of body sizes at sexual maturity and at sex change in the parrotfishes of Hawaii: input needed for management regulations and stock assessments

First estimates of sex allocation patterns and body size‐at‐sexual maturity and at protogynous sex change are presented for the five major (including one endemic) species of parrotfishes of Hawaii. Median body size at initial maturation as a female (L_M50) and at protogynous sex change from adult female to adult male (L_Δ50) varied greatly among the five species. Estimates of L_M50 were about 14, 17, 24, 34 and 35 cm fork length (L_F) in palenose Scarus psittacus, Pacific bullethead Chlorurus spilurus, stareye Calotomus carolinus, spectacled Chlorurus perspicillatus and redlip parrotfish Scarus rubroviolaceus. Values of L_Δ50 were c. 23, 27, 37, 46 and 47 cm L_F in the respective species. Length at female maturation was proportional to maximum body size (L_max) of the respective species, ranging from 50 to 72% and averaging 62% of L_max across species. L_Δ50 was also proportional to L_max, ranging from 82 to 97% and averaging 92%. Males of both pairs of Scarus and Chlorurus spp. reported here are diandric. Only one of the five major species (C. carolinus) is functionally monandric, with either all or nearly all males secondarily derived from adult females. The broadly differing absolute body sizes at sexual maturation and at sex change among the five species have important implications for improving regulatory size limits for parrotfishes in the State of Hawaii, where parrotfish species have historically been managed based on a single minimum size limit of 30·5 cm L_F. This study provides a model demonstration of why catch data for parrotfishes, and other size‐structured reef‐fish populations, should be recorded either by species or by functional size‐groups of species that allow setting more meaningful minimum size limits.