Age,growth and mortality of invasive sharpbelly,Hemiculter leucisculus (Basilewski, 1855) in Erhai Lake,China

The sharpbelly Hemiculter leucisculus, an invasive species, has expanded its range throughout much of Asia and into the Middle East. However, little is known of its adaptive changes regarding life history traits such as age, growth and mortality that could possibly explain its success as an invasive species. A detailed study of the invasive sharpbelly was conducted based on 4539 samples collected from July 2009 to June 2011 in Erhai Lake, China. Standard length ranged from 4.3–19.1 cm for females and 4.6–12.3 cm for males. Length–weight relationships for females and males were significantly different and described as W = 0.0076SL^3.2608 and W = 0.0084SL^3.1901, respectively. Otoliths are ideal for age determination because of the single annulus formed each year. Based on marginal increment analysis, the total mean CV for age estimate between two readings was 3.55%. The von Bertalanffy growth curves computed by observed length‐at‐age data were expressed as L_t = 25.6 (1 ? e^{?0.176 (t + 1.347)}) for females and L_t = 16.4 (1 ? e^{?0.354 (t + 0.819)}) for males. According to the age, growth and mortality data, there are three possible reasons for H. leucisculus attaining such dominance within a short time in Erhai Lake. First, because of the simple age structure of this species: 97.58% of males were 1–2 years old with a maximum age of only 3 years; 93.14% of females were 1–3 years old, with a maximum age of 6 years. Second, females grew larger than males at any age. Third, instantaneous mortality rates were much higher for males (4.22 year^?1) than for females (1.17 year^?1).     

Age,growth, mortality and sex ratio of the inshore population of the edible crab,Cancer pagurus (Linnaeus 1758) in South Wales (UK)

Age, growth, and mortality of the edible crab, Cancer pagurus, were determined for the native population in South Wales (UK). Sampling was carried out on a monthly basis between February 2001 and September 2002. Carapace width ranged between 10.4 and 163 mm. Based on the carapace width frequency distribution, the Swansea and Gower population was composed mainly of males belonging to the first and second age‐class (1 and 2), and of females belonging to the third and fourth age‐class (3 and 4). Sex ratio was 1.126 ± 0.27 in favour of males. Carapace width frequency distributions and weight‐at‐age data were used to estimate the von Bertalanffy growth equation parameters. For the population as a whole, these were: L∞ = 199 mm, W∞ = 1179.56 g, K = 0.24 year^?1, t₀ = ?0.1004 years. The overall carapace width–weight relationship was: W = 0.38(CW^2.69). Analysis of covariance indicated a significant difference in the carapace width–weight relationship between males and females in the study area. Total mortality Z and natural mortality M rates for combined sexes were 1.245 year^?1 and 0.567 year^?1, respectively. The exploitation ratio E was estimated to be 54.43%.     

Length‐weight relationship and biological data of a threatened fish,Ptychobarbus chungtienensis (Tsao, 1964) in Bita Lake of Shangri‐La,Yunnan, China

This paper provides the length‐weight relationship (LWR) and other biological information of a threatened plateau freshwater fish species Ptychobarbus chungtienensis in the subfamily Schizothoracinae of the family Cyprinidae, from the Bita Lake of Shangri‐la, in Yunnan, China. The LWR was BW = 0.00954 TL^2.95 for a total of 392 individuals, where the coefficient b was close to 3.0, suggesting a near‐isometric growth in this species. The total length: standard length relationship was TL = 0.399 + 1.151 SL. Fitting a von Bertalanffy growth function to the observed length‐at‐age data resulted in L_(t) = 53.1 (1‐e^?0.08(t?0.2)). The natural mortality rate (M) was 0.20 year^?1. Length at first maturity (Lm) was 20.57 cm, and 6.3 years the theoretical estimated age at first maturity (Am). Ptychobarbus chungtienensis mature gradually beginning in May, reaching a reproduction peak around August, with most individuals completing reproduction by October. The gonadosomatic index (GSI) was highest in August (GSI = 0.1351) and lowest in October (GSI = 0.0467). The male index (GSI = 0.0866) was lower than in females (GSI = 0.1466) (P < 0.05). Mean condition factor (Km) of P. chungtienensis was 0.8500, and not significantly different between sexes (P = 0.124), but differing significantly between seasons. In October the condition factor (Km = 0.9211) was significantly higher than in May (Km = 0.8379) or in August (Km = 0.8412) (P < 0.05).     

Length–weight relationship,parameters of growth and mortality for the hardhead halfbeak Chriodorus atherinoides Goode & Bean, 1882 (Beloniformes: Hemiramphidae) from Yucatan Peninsula,Mexico

This study reports length–weight relationships and growth parameters for Chriodorus atherinoides from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. A total of 667 specimens were collected between April 2009 and March 2010. The length‐weight relationship obtained was W = 0.0034Lt^3.22. This study presents the first estimation of the model parameters of the von Bertalanffy growth equation (L_∞ = 27.30 cm, k = 0.76 year^?1 and t₀ = ?0.178 years), the instantaneous total mortality (2.51 year^?1) and the maximum length record (26.0 cm total length), which is greater than previously recorded.     

Age and growth characteristics of Schizopygopsis younghusbandi Regan, 1905 in the Yarlung Tsangpo River in Tibet,China

To better understand the biology of Schizopygopsis younghusbandi Regan, 1905 and its relationship with management considerations, this study describes the relationships between otolith size and fish length and age, verifies annual periodicity of otolith annulus formation, and estimates the S. younghusbandi growth parameters. These age and growth characteristics were studied using 694 specimens collected from August 2008 to August 2009. Otoliths grew asymmetrically throughout the range of standard length (SL) studied, showing a clear pattern of alternating translucent and opaque bands. Marginal increment ration (MIR) analysis of specimens up to 6 years of age indicated that one opaque band and one translucent band were laid down each year. Maximum observed age was 17 years, corresponding to a female of 35.8 cm SL and 589.1 g body weight (BW). The SL‐BW relationship was described as BW = 1.122 × 10^?5 SL^3.030 for sexes combined. The von Bertalanffy growth function was used to model back‐calculated lengths as L_t = 338.4 (1?e^{?0.233 (t + 0.403)}) for males, and L_t = 433.9 (1?e^{?0.194 (t + 0.397)}) for females. Growth performance of S. younghusbandi was relatively higher than those of other Schizothoracinaes inhabiting the same river.     

Reproductive biology of Chinese minnow Hemiculterella sauvagei Warpachowski, 1888 in the Chishui River,China

This study describes the reproductive biology of the Chinese minnow Hemiculterella sauvagei. The length‐weight relationship, sex ratio, spawning season, size at first maturity, and fecundity were analyzed based on 685 specimens collected from the Chishui River between July 2011 and July 2012. The relationship between standard length (SL) and body weight (BW) were estimated as BW = 2.14 × 10^?4 × SL^2.801 (R² = 0.839; N = 413; P < 0.05) for females and BW = 1.31 × 10^?4 × SL^3.001 (R² = 0.868; N = 272; P < 0.05) for males. The female to male sex ratio, 1.52 : 1, differed significantly from a 1 : 1 ratio. Females predominated in standard lengths >12 cm. Analyses of the monthly variation in the gonadosomatic index (GSI), the monthly proportions of macroscopic gonadal maturity, and the size distribution of oocytes consistently suggested a prolonged spawning season of H. sauvagei from March to August, with a peak from April to May. Logistic curves describing the relationship between proportion of maturity (P_r) at each length interval and standard length were estimated as P_r = 1/(1 + e^{26.867–0.306SL}) (R² = 0.999; N = 413; P < 0.05) for females and P_r = 1/(1 + e^{10.522–0.142SL}) (R² = 0.999; N = 272; P < 0.05) for males. Size at first maturity was estimated as 7.4 cm for males and 8.8 cm SL for females. Absolute fecundity varied from 563 to 5052, with a mean of 2413 ± 874 oocytes per ovary. The relative fecundity was estimated to be 41–299, with a mean of 171 ± 55 oocytes per ovary. The present study provides useful information for fishery management and resources conservation.     

Age,growth and reproduction of the black sea bream Spondyliosoma cantharus (Linnaeus, ) (Sparidae) in the Gulf of Annaba (Algeria)

The objective of this study was to determine the basic population‐specific parameters necessary for fish stock assessment in the Gulf of Annaba and to compare these with data from other Mediterranean regions. Black sea bream Spondyliosoma cantharus (Linnaeus, 1758) (N = 501) were collected monthly from January to December 2008 along the Algerian eastern coasts. More than 22 fish were collected each month and ranged in size from 13.4 to 40 cm total length, weighing from 36 to 1080 g eviscerated weight. Biological sampling included weighing and measuring the fish, gonad weighing, sex and maturity stage determination, and age estimation through otolith readings. Validity of the otolith readings for estimating age and growth was supported using the back‐calculation method. Estimated parameters of the von Bertalanffy model are: L_∞ = 33.54 cm, W_∞ = 633.46 g, k = 0.52 year^?1 and t_o = ?0.04 year. The growth performance index (φ) is: 2.76. The length‐weight relationship is: EW = 4.4.10^?6 TL^3.23. The spawning period occurred from February to May, while the gamete emission peaked in April. Females reached sexual maturity at 19.3 cm (2 years) and males at 21.3 cm (3 years). Sexual inversion occurs at approximately 24.3 cm. Spondyliosoma cantharus was characterized as being a protogynic hermaphrodite.     

Age,growth and feeding habits of the bluemouth rockfish,Helicolenus dactylopterus dactylopterus (Delaroche 1809) in the central Mediterranean (southern Tyrrhenian Sea)

This paper provides data on age, growth and diet of the bluemouth rockfish, Helicolenus dactylopterus dactylopterus (Scorpaenidae), central Mediterranean Sea. Estimated by otolith readings, ages ranged from 0 to 21 years. Parameters of the von Bertalanffy growth curves were L_inf = 26.1 cm, k = 0.14 year^?1, t₀ = ?1.92 years and the growth performance index was Φ = 1.98. The weight‐length relationship, W = 0.016 TL^2.99; R² = 0.99, described an isometric growth of the species. This species is a carnivore focusing mainly on the crustaceans Goneplax rhomboides and Lophogaster typicus. Statistical analysis showed an ontogenetic shift between small (4.0–6.3 cm) and larger fishes. Significant differences were also found in relation to the sampling depth.     

Age and growth of damselfish Chromis notata (Temminck & Schlegel, 1843), Jeju Island,Korea

This study investigated the age and growth of damselfish, Chromis notate, from Jeju Island in Korea. Samples were collected monthly by lift net from September 2013 to August 2014. Total lengths of the damselfish ranged from 6.4 to 15.3 cm. The relationship between total length and wet weight was WW = 0.0125TL^3.1631 for females, and WW = 0.0091TL^3.2769 for males. The slopes in the relationship between length and weight were not significantly different between sexes, but were significantly different in the intercepts. There were more female than male specimens (1.3:1). Age determination was conducted using the otoliths. Marginal increment (MI) declined in summer and winter, which suggests that two rings are formed each year. Ages of sampled individuals ranged from 1 to 5 years. Length‐at‐age data were fitted using the von Bertalanffy growth model. The estimated growth functions were L_t = 19.93 [1 ? exp^{?0.21 (t + 0.811)}] total length and wet weight was females, and L_t = 16.47 [1 ? exp^{?0.32 (t + 0.499)}] for males.     

Length‐weight relationship and seasonal effects of the Summer Monsoon on condition factor of Terapon jarbua (Forsskål, 1775) from the wider Gulf of Aden including Socotra Island

The present study investigates the length‐weight relationship and condition factor of populations of the Indo‐Pacific fish Terapon jarbua ( Forsskål, 1775 ) collected in the wider Gulf of Aden, notably from Socotra Island and the Hadramout coast of Yemen. This region displays a monsoon climate, with wide seasonal variations affecting estuarine habitats. A total of 620 specimens collected in estuaries and at sea were measured and weighed during field surveys carried out in 2007 and 2008 during pre‐ and post‐ South‐Western monsoon periods. The length‐weight relationship of the studied populations of Terapon jarbua was determined as W = 0.0288 × SL^2.99, with r² = 0.96 and consistent with existing data on the species from other regions. Significant seasonal differences were found in Fulton’s condition factor of Terapon jarbua.     

Age,growth and reproduction of the sand smelt Atherina boyeri Risso, 1810 in Mellah Lagoon (Eastern Algeria)

This aim of this paper was the study of the reproductive biology and growth of the sand smelt, Atherina boyeri, in Mellah Lagoon (Algeria). These data are important for the sustainable exploitation of the stocks of this species. Examined was a total of 1402 Atherina boyeri specimens captured monthly from March 2010 to March 2011, in a population with a 3‐year life cycle. Length–weight relationship was estimated as W = 0.0047 L^3.077 (r² = 0.935) for males and W = 0.0047 L^3.176 (r² = 0.935) for females. Using scales, the von Bertalanffy growth function fitted to back‐calculated size‐at‐age data was Lt = 9.49 [1 ? e^{?0.316 (t + 0.928)}] for males, and Lt = 11.67 [1 ? e^{?0.179 (t + 1.514)}] for females; using otoliths this was Lt = 9.68 [1 ? e^{?0.3 (t + 1.02)}] for males, and Lt = 11.93 [1 ? e^{?0.171 (t + 1.55)}] for females. The growth performance index (Φ) indicated that males (Φ_scales = 3.34, Φ_otoliths = 3.33) grew at the same rate as females (Φ_scales = 3.19, Φ_otoliths = 3.24), with a sex ratio of 1 : 1.6 in favor of females. The reproductive season extended from February to June. Individual length at first sexual maturity was 4.20 cm for 1‐year‐old males and 4.35 cm for 1‐year‐old females.     

Age,growth, reproduction and feeding of John Dory,Zeus faber (Pisces: Zeidae), in the Saros Bay (North Aegean Sea)

The age, growth, reproduction, sexual maturity and stomach content of John Dory (Zeus faber), caught in the Bay of Saros (North Aegean Sea) between September 2006 and September 2008, were investigated. The female‐male ratio was 1.6 : 1. The total length of females ranged from 13.8 cm to 52.8 cm, and of males from 12.2 cm to 42.9 cm. The length‐weight relationship was W = 0.0174*L^2.936. Age data derived from vertebral centra readings were used to estimate the growth parameters of the von Bertalanffy equation. Growth parameters for females were L_∞ = 58.50 cm K = 0.11 year^?1, t₀ = ?0.99 year and for males L_∞ = 45.01 cm, K = 0.13 year^?1, t₀ = ?1.17 year. Maximum age was 18 years for females and 17 years for males. Length at first maturity for both females and males was 25.4 cm. Monthly values of the gonadosomatic index indicated that spawning occurred mainly in two peaks: one between January and June, and the other from August to September. Stomach content analysis showed the most‐preferred prey to be Pisces (IRI% 97.3).     

Age determination and growth estimates of the white‐spotted conger eel,Conger myriaster (Brevoort, 1856) in marine waters of South Korea

The age and growth of conger eel, Conger myriaster, were investigated by measuring transversely sectioned sagittal otoliths samples from 635 individuals. Sample ages ranged from 1 to 13 years in the female data. Parameters of the von Bertalanffy growth function were estimated using nonlinear regression from back‐calculation, mean length of samples at age relationships, and otolith weight‐at‐age relationships. Best‐fitting value of the three methods was the otolith weight‐at‐age relationship (r² = .87). Parameters of otolith weight‐at‐age were estimated as L_∞ = 143.76 cm, K = 0.081, and t₀ = ?1.285. Maximum oocyte diameter (MOD) ranged from 50 to 430 μm. Reproductive traits of ovaries showed a positive relationship between GSI and MOD (r² = .8515). It is suggested that oogenesis begins to develop from 4 years of age and at lengths of about 45 cm TL. In conclusion, these data provide reliable fundamental data for the fish stock management of Conger myriaster in South Korea.     

Age and growth of Atlantic bonito (Sarda sarda Bloch, 1793) in the Sea of Marmara and Black Sea,Turkey

Age and growth of Atlantic bonito (Sarda sarda Bloch, 1793) were determined in the Black Sea and Sea of Marmara from October 2003 to May 2005. A total of 694 samples ranging from 23.5 to 71 cm total length was collected; age estimates were carried out on otoliths of 248 fish. Male and female fish ages were estimated as up to 3⁺. The length–weight relationship and the von Bertalanffy growth curve (TVBGF) were described for all individuals as: W = 0.0054L^3.215 and L_t = 68.01 [1 ? e^{?0.895 (t + 0.395)}]. These data are discussed in relation to other growth studies of S. Sarda in the Mediterranean Sea.     

Age and growth of the Giant Kelpfish,Heterostichus rostratus Girard 1854, in Southern California,USA

In order to update existing life history parameters, age and growth patterns were determined for Giant Kelpfish, Heterostichus rostratus sampled from nearshore kelp forest and estuary habitats in southern California (USA) from April 2012 through June 2015. Fish were collected by pole spear, beach seine, beam trawl, purse seine, and square enclosure. Using age‐at‐length data derived from otolith readings, Giant Kelpfish were found to have a relatively short life span with the largest examined fish reaching a maximum total length of 413 mm at an age of 5 years. Von Bertalanffy growth parameters estimated for this species were: L_∞ = 45.1 cm, k = 0.25, t₀ = ?0.66. Standard length (SL, cm)‐total length (TL, cm) and total length (TL, cm)‐weight (W, g) relationships were described by the equations: SL = 0.90 TL – 1 and W = 2.21 × 10^?3 TL^3.39, respectively. Wild juvenile Giant Kelpfish collected for this study had a higher growth rate than laboratory‐reared fish from a previous study.     

Length–weight relationships and growth parameters of two endemic fish species (Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis Miller, 1955) from the Yucatan Peninsula,Mexico

This study reports length‐weight relationships and growth parameters for Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis Miller, 1955 from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. Specimens were collected between April 2009 and March 2010. The resulting length‐weight relationship for F. polyommus was: W = 0.0180 Lt^3.37 and W = 0.0142 Lt^3.35 for F. persimilis. This study presents the first estimation for both species of the von Bertalanffy growth model parameters, the growth performance index, the L₅₀, and is the first report of the length‐weight relationship for F. persimilis.     

Some biological characteristics of Hemigrammocapoeta kemali (Hanko, 1924) in Işıklı Lake (Denizli-Turkey)

Totals of 284 Hemigrammocapoeta kemali specimens were caught during 1998 in the I??kl? Lake, Turkey. Their ages, lengths and weights were determined to estimate length–weight relationships and age composition. Fecundity and oocyte diameter were also determined. The sex ratio was 1 : 1.29. Fork length and total weight of specimens ranged from 3.4 to 8.2 cm and from 0.5 to 6.9 g, respectively. Maximum age observed was 4 years. The length–weight relationship for all fish was best described by the equation W = 0.0121*L^3.06; the von Bertalanffy growth equations for length and weight were Lt = 8.73[1?e^{?0.401(t + 0.947)}]; Wt = 9.17[1?e^{?0.401(t + 0.947)}]^3.06. Oocyte numbers varied from 220 to 1159 and oocyte diameters ranged between 450 and 900 μm.     

Age and growth of pearly razorfish,Xyrichtys novacula (Linnaeus 1758), in the central Mediterranean Sea

Age and growth of pearly razorfish Xyrichtys novacula (Labridae) were determined in specimens caught on sandy bottoms by surrounding nets and lines (depth range 5–30 m) between January 2000 and December 2002. The study location was in the central Mediterranean Sea. For this purpose the annual growth increments (annuli) in sagittae were analysed. A total of 470 individuals of X. novacula, ranging from 49 to 200 mm TL (total length), were examined. Conversion between total length and standard length was calculated and represented by the relationship: . Edge analysis on otoliths was carried out to validate seasonality deposition. Seven age‐classes were determined from 0+ to 6+. The linear relationship between maximum otolith length (OL) and TL was summarized in the equation . The estimated parameters of the von Bertalanffy growth function were L = 175.05 mm, k = 0.80 year^?1, t₀ =?0.73 years and the growth performance index calculated as (Φ = 2.39). The length–weight relationship W = 0.0139 TL^2.9326 described an isometric growth for the species in this area.     

Identifying growth parameters for two endemic species [Capoeta antalyensis (Battalgil, 1943) and Pseudophoxinus antalyae Bogutskaya, 1992] in Duden Creek,Antalya, Turkey

It is hypothesized that Capoeta antalyensis (Battalgil, 1943) and Pseudophoxinus antalyae (Bogutskaya, 1992) might display specific growth characteristics that differ from other species of their genus. Age and growth were described for species from Duden Creek (Antalya, Turkey) from February 2008 to January 2009. The length–weight relationship for all individuals were described by the parameters: a = 0.0143 and b = 2.946 for C. antalyensis and a = 0.0084 and b = 3.251 for P. antalyae. The von Bertalanffy growth parameters based on data from scales were L∞ = 35.78 cm, k = 0.251 year^?1 and t₀ = ?0.30 for C. antalyensis and L∞ = 22.59 cm, k = 0.232 year^?1 and t₀ = ?0.78 for P. antalyae. The growth characteristics for these two species are not much different from those of closely related species from the same genus.     

A study on age and growth characteristics of spiny gurnard (Lepidotrigla dieuzeidei Blanc & Hureau, 1973), northeastern Mediterranean Sea

This study investigated the age and growth characteristics of spiny gurnard, Lepidotrigla dieuzeidei, from the northeastern Mediterranean. Samples were collected by commercial trawls during the 2012–2013 fishing seasons. A total 1,878 speciments ranged from 7.10 to 15.90 cm total length and 2.28–35.88 g in weight. Female/male ratio was 1.2/1. The total length–weight relationship was W = 0.002 TL^3.579 (r² = .909) for sexes combined, W = 0.0021 TL^3.551 (r² = .914) for males and W = 0.0019 TL^3.602 (r² = .904) for females. Age determination was conducted using the sagittal otoliths. Ages of examined individulas ranged from 3 to 11 years. Total length‐at‐age data were fitted using the von Bertalanffy growth model. Estimated growth functions were TL_t = 18.100 [1?e^{?0.14 (t + 0.63)}] for sexes combined, TL_t = 23.587 [1?e^{?0.08 (t + 1.56)}] for males and TL_t = 16.612 [1?e^{?0.19 (t + 0.15)}] for females.