Population ecology parameters and biomass of golden grey mullet (Liza aurata) in Iranian waters of the Caspian Sea

This paper examines the changes in the population ecology parameters and biomass of golden grey mullet (Liza aurata) in Iranian waters of the Caspian Sea from 1991 to 2005. For most years during this 14-year period, we estimated the age structure of the catch, length–weight relationship, von Bertalanffy growth parameters, condition factor, natural and fishing mortality and biomass. Growth parameters were estimated as L_∞ = 62.7 cm, K = 0.15 year⁻¹, t₀ = −0.23 year⁻¹. The instantaneous coefficient of natural mortality was estimated as 0.350 year⁻¹ and the instantaneous coefficient of fishing mortality varied during the 14-year period between 0.111 to 0.539 year⁻¹. Biomass estimates of golden grey mullet, from the biomass-based cohort analysis were increased from 13,527 mt in 1991–1992 to 23,992 mt in 2002–2003. In 2004–2005, it was estimated to be 23,658 mt. We concluded that at the present time, the stock of golden grey mullet is not being over-fished.     

鱼类生长的幂指数生长方程

研究鱼类生长往往需要选择适当的数学模型来处理实际数据以表征生长的某些特点 ,或用于比较生长速度 ,或用于消除随机因素的影响 ,使生长曲线圆润化 ,以显示生长的趋势。其中受到高度重视并被广泛应用的是贝特朗菲方程 (ｖｏｎＢｅｒｔａｌａｎｆｆｙｅｑｕａｔｉｏｎ)。然而该模型在理论上有不足之处 ,适用范围也不够理想。为此 ,取陆文杰[1] 对林木生长研究中提出并命名的数学模型———幂指数生长方程 ,用大量的鱼类生长数据[2 -6] 验证结果 ,证实该方程比贝氏方程更适于研究鱼类生长规律。1　材料与方法1 .1　数据及其来源共 12 4份 ,75…     

大西洋海域大眼金枪鱼年龄与生长的初步研究

根据2001年6~10月在大西洋海域金枪鱼延绳钓渔业中采集的89 ind大眼金枪鱼样本,对其叉长、体重进行测定,并以脊椎骨作为年龄鉴定材料。结果表明,叉长组成为85~186 cm,体重组成为11.5~132.5kg,年龄为2~6龄。体重与叉长关系式为W=4.5026×10-5×FL2.8200。利用一般Von Bertalanffy生长方程来拟合,叉长和体重生长方程为:FL=257.90×(1-e-0.1960(t+3.7919))2.5933,Wt=284.28×[(1-e-0.1960(t+3.7919))2.5933]2.8200。叉长和体重的生长拐点分别为1.07龄和5.75龄。     

Analysing the growth of turbot (<Emphasis Type="Italic">Psetta maxima</Emphasis>) in a commercial recirculation system with the use of three different growth models

The growth data of a commercial aquaculture recirculation system were analysed to investigate the growth performance of reared turbot (Psetta maxima). Three common growth models (von Bertalanffy, Gompertz and Schnute) were fitted to the growth data documented over a time period of 6 years. To determine the most suitable model, three different criteria were used: (1) the Akaike index criterion, (2) the sum of squared residuals and (3) the average daily deviation between the estimated final weight and the observed final weight. The evaluation of the growth models showed that the Schnute model had the lowest Akaike index, the lowest sum of squared residuals and the lowest daily deviation between estimated and real weight of all tested growth models. The Schnute model produced sigmoid growth curves. The estimated growth coefficients were the most realistic ones in regard to biological interpretation. In contrast, the von Bertalanffy growth model and the Gompertz model estimated inaccurate exponential growth curves and are therefore unable to simulate the growth data as well as the Schnute model. The results indicate that the von Bertalanffy growth model is not the optimal model to simulate the present growth data and that the growth potential of reared turbot has probably not yet been fully exploited in the aquaculture system(s) examined (so far).     

Retrospective analysis of Atlantic salmon (Salmo salar) marine growth and condition in the northwest Atlantic based on tag‐recovery data

The life history of North American Atlantic salmon (Salmo salar) is characterized by extensive round‐trip migrations between freshwater rearing habitats and marine feeding grounds off the coasts of Canada and Greenland. Growth is rapid during the marine migration, and growth rate and condition factor may be indicators of salmon health during this period. Growth data were evaluated from a tag‐recovery program conducted from 1969 to 1991 using hatchery‐reared Atlantic salmon smolts released in the Penobscot River, Maine, U.S.A. Information from recaptures of 3167 salmon that were at large in the marine environment for 1 month to 3 yr was analyzed. Length–weight measurements coupled with time‐at‐large data were used to estimate von Bertalanffy and allometric growth parameters specific to the marine phase. Variations in growth and condition factor in relation to smolt age, release date, and temperature conditions in the northwest Atlantic were also examined. The von Bertalanffy k parameter declined with ordinal release date, indicating faster growth rates during the first year of smolts released earlier in the spring. The 2‐yr‐old smolts had a larger k than 1‐yr‐old smolts, although 1‐yr‐old smolts grew to a larger asymptotic size. Sea surface temperature had variable effects on growth parameters and condition factor, with temperature at the beginning of the migration and in overwintering habitat during the first year at sea having the greatest influence on length–weight relationships. Determining the mechanisms that influence growth of individuals during the marine phase will help elucidate the factors responsible for historic growth trends, establishing a baseline for current research.     

Estimation of temporal changes in the growth of green turtles <Emphasis Type="Italic">Chelonia mydas</Emphasis> in waters around the Ogasawara Islands

Biological and life-cycle information is essential to any fisheries management program. We have investigated temporal changes in growth parameters in the von Bertalanffy growth curve for green turtles, Chelonia mydas, in waters around the Ogasawara Islands. The variance model of individual variability of growth used in our study was one derived from the stochastic differential equation with the white noise of constant intensity. Maximum likelihood estimates of the parameters were made using the data of 102 recovery records of tagging experiments from 1974 to 1995. The estimations were carried out for each of two models of linear and sudden changes in the parameters, and the best model was selected using Akaike's information criterion. The selected model was that all of the parameters excepting asymptotic straight carapace length were linear functions of year and that the asymptotic length was constant over the years. The estimated values of the growth coefficient in 1974 and 1995 were 0.0317 and 0.192 per year, respectively, and the estimated value of the asymptotic straight carapace length was 97.2 cm. Implications of the results and future issues to be resolved in near future are discussed.     

长江干流圆口铜鱼的年龄与生长研究

采用鳞片材料对采自长江干流宜昌和重庆江段圆口铜鱼（Coreius guichenoti）的年龄进行鉴定,并对其生长方程、生长拐点等生物学特征进行了研究。结果表明,调查江段圆口铜鱼的年龄组成以1、2龄个体为主;体长（L）和鳞径（R）呈线性关系,L=15.327R＋71.349;体重（W）与体长（L）呈幂指数关系,W=0.00002L2.9942;体长von Bertalanfy生长方程为Lt=730.15[1-e-0.12（t＋1.01）];体重生长方程为Wt=7493.05[1-e-0.12（t＋1.01）]2.9942;其生长拐点年龄为8.13龄。圆口铜鱼体长生长3龄前为快速期,之后生长减缓。为了保护长江干流圆口铜鱼资源,建议以278mm为最小捕捞个体的体长。     

The utility of otolith weight as a predictor of age in the emperor Lethrinus mahsena and other tropical fish species

This study examines the potential use of otolith weight as a proxy for age in the lethrinid Lethrinus mahsena from different sites in the tropical Indian Ocean: the banks of Seychelles, Mauritius and British Indian Ocean Territory (BIOT, Chagos Archipelago). The reliability of age–frequency distributions and individual ages estimated using otolith weight–age relationships was examined through comparison with those estimated through the standard method of ageing using otolith increments. Two other methods for estimating age–frequencies using age-slicing via an estimated growth curve were also examined; these used growth curves estimated by a length-based method (ELEFAN), or by fitting directly to length-at-age data (an ‘age-based’ method). Age-slicing using length-based growth parameters failed to produce reliable age–frequencies, due to inaccuracies in the growth parameter estimates. The use of age-based growth parameter estimates improved the results of age-slicing, however, age–frequencies remained significantly different from those obtained from ageing using otolith increments in two locations. The use of otolith weight–age relationships resulted in estimated age–frequency distributions that in all locations were not significantly different from those assessed through otolith increment counts. In contrast, L. mahsena otolith weight–age relationships could not be used to estimate individual ages accurately, due to the level of overlap in otolith weight between age classes. Where otolith increments are routinely used to age commercial fish species, the fact that otolith weight–age relationships could not be used to age individuals accurately may limit its application. However, where routine ageing of individuals through otolith increments is considered impractical, for instance because of its cost, the use of otolith weight–age relationships to derive catch age–frequencies represents a viable alternative approach. With this in mind, this study has also demonstrated that there is the potential to use otolith weight–age relationships for five other species caught around the Seychelles, following the validation of their otolith increments.     

Age and growth of yellowstriped butterfish, <Emphasis Type="Italic">Labracoglossa argentiventris</Emphasis>, around Izu Oshima Island

ABSTRACT:   Age and growth of the yellowstriped butterfish, Labracoglossa argentiventris , around Izu Oshima Island were studied using a total of 1450 fish. Age was determined by counting the edge of the opaque zones as a ring mark on sectioned sagittal otoliths. Formation of the first ring was observed during spring or summer, corresponding to 1.5 years after hatching. Thereafter, one ring was formed each year in the same season as the previous year. The growth of the butterfish was rapid until 2 years of age. The maximum likelihood method was applied to the age and length data for estimating parameters in von Bertalanffy, Gompertz, and Logistic growth models. The selected model, based on the Akaike Information Criterion, was the von Bertalanffy growth model, which indicated differential asymptotic length and variance by sex.     

Perspectives for development of low impact aquaculture in a Western Mediterranean lagoon: the case of the carpet clam Tapes decussatus

Some 30,000 specimens of the Mediterranean clam Tapes decussatus were suspended in nylon bags of two different mesh sizes and pre-grown in the Calich lagoon (Sardinia, Italy) from March to June 2001. The samples differed in size at the end of the pre-growth stage. They were then sown at a density of 650 specimens m^–2 in two stations of the lagoon. The growth rates in the stations were different according to the Von Bertalanffy model. Primary and secondary plankton production was calculated by field measurements as well as by modelling. The results indicate that the Calich lagoon could produce a maximum of 753.25 g m^–2 yr ^–1 WW, with shell, for Tapes decussatus. Our culture experiments lasted 15 months with an estimated mortality of 50% and the yield of T. decussatus was 4.3 times greater than the calculated natural production.     

Age determination and growth of Pacific bluefin tuna, Thunnus orientalis, off Japan and Taiwan

Age determination of wild captured Pacific bluefin tuna, Thunnus orientalis, was conducted using sagittal otoliths of 806 specimens (47–260 cm in fork length) caught in the waters off Japan and Taiwan. Otoliths were transversely sectioned and the opaque and translucent zones were analyzed. Opaque zones mainly appeared on the otolith edge from April to July, indicating that the opaque zone is formed annually. The opaque zones formed during later life (age 10+) were more distinct than the earlier zones. The estimated ages of specimens ranged from 1 to 26 years. Parameters of the von Bertalanffy growth function were estimated to be 249.6 cm, 0.173, and −0.254 years for L_∞, k, and t₀, respectively. Growth of younger fish was rapid up to 5 years old attaining about 150 cm, and then growth rate decreased. After that, fish attained about 200 cm at 9 years old and about 225 cm (90% of L_∞) at 13 years old (50% of maximum age). This paper updates the biological information on length at age with a large size range to support stock assessment model analyses for this commercially valuable species.     

三疣梭子蟹“中宁1号”的形态性状增长规律

以1~6月龄三疣梭子蟹"中宁1号"为材料,采用Logistic、Gompertz和von Bertalanffy3种模型分别拟合了体质量、体长、全甲宽、甲宽、体高、大螯长节长、大螯不动指长及第一步足长节长共8个形态性状的生长特征,旨在寻找各性状的最佳生长模型,并对其增长规律进行研究。结果表明:三疣梭子蟹体质量性状生长过程以Logistic生长模型(R2=0.999)的拟合效果最佳;除体质量外的其它7个性状则均以von Bertalanffy生长模型(R2为0.990~0.994)拟合效果最好;各性状模型经ANOVA检验后均具有统计学意义(P0.01)。根据各性状的最佳生长模型得出各性状的极限值分别为体质量231.44 g、体长84.45 mm、全甲宽164.44 mm、甲宽128.47 mm、体高43.69 mm、大螯长节长59.96 mm、大螯不动指长90.89 mm、第一步足长节长37.20 mm。体质量的快速生长区间及拐点分别为2.14~3.91月龄及3.02月龄;其它7个性状快速生长区间的始速点为0月龄,终速点为2.05~2.35月龄,拐点在1月龄左右。各性状间的生长速率、生长加速率、相对增长率与绝对增长率存在一定差异。总之,体质量性状生长过程符合"慢-快-慢"的特征,其它性状则表现为"快-慢"的特征。以上结果可为三疣梭子蟹"中宁1号"选择育种及养殖生产提供参考依据。     

怒江细尾高原鳅生长特征与食性

对2008年从怒江采集到的172尾细尾高原鳅(Triplophysa stenura)进行了生长与食性的研究。并采用von Bertalanffy生长方程、Gompertz生长方程、Logistic生长方程以及三项式方程分别拟合了细尾高原鳅的生长。实验结果显示,耳石适合于细尾高原鳅的年龄鉴定。体长与体重关系式为W=0.9996×10-5L2.9762(R2=0.9680)。体长与耳石半径间关系式为L=0.0027R1.7230(R2=0.9542)。四种生长方程均能反映其生长规律,其中von Bertalan-ffy生长方程表达式为Lt=246.9430(1-e-0.05964(t-0.1689));Wt=132.0300(1-e-0.05964(t-0.1689))2.9762。体重、生长曲线的拐点为18.45龄。食性分析表明:细尾高原鳅为杂食性鱼类,食物组成主要是水生昆虫幼虫,着生藻类,原生动物及有机碎屑等。     

Geographic variability of sardine growth across the northeastern Atlantic and the Mediterranean Sea

This study describes broad-scale spatial variations in sardine growth across the northeastern Atlantic and Mediterranean waters using opportunistic samples collected in recent years. More detailed information on spatial, decadal and seasonal growth variations is provided for the Iberian-Biscay region using data collected in acoustic surveys since the mid-1980s. Growth curves are fitted to annual or monthly length-at-age data using a robust Von Bertalanffy model; parameters for recent samples are compared with literature information using an auximetric plot while differences between areas within the Iberian-Biscay region are tested by log-likelihood ratio tests. Sardine growth performance is generally lower in the Mediterranean and declines across the northeastern Atlantic from the English Channel to north Morocco but increases sharply off Mauritania. Lower growth of Mediterranean sardines is possibly associated to the overall oligotrophy of this Sea while differentiation from the Atlantic is likely sustained by reproductive isolation between populations from the two areas. Within the northeastern Atlantic, size- and age related migrations may partly explain differences in maximum length/age and mean length-at-age between neighbouring areas but the broad-scale latitudinal decline in growth is consistent with adaptation to the north–south decline in seasonal temperature gradients and to the annual cycles of plankton production. Within the Atlantic Iberian waters, sardine grows and improves in condition during spring and summer when the allocation of energetic resources for gonad development cease, temperature is close to the annual maxima and plankton production is high. Variation in sardine length-at-age and growth within the Atlanto-Iberian stock area has implications for stock structure and needs to be taken into account in the calculation of weight and maturity-at-age for assessment purposes. No evidence of broad temporal changes in sardine growth within the Iberian-Biscay region is obtained.     

Fecundity and growth-dependent mortality of Pacific anchovy (Engraulis japonicus) in Korean coastal waters

We propose a method of estimating natural mortality of marine pelagic fishes, especially for early-life stages, based on their fecundity. To estimate size-dependent fecundity, growth and mortality of Pacific anchovy (Engraulis japonicus), the most abundant fish species in coastal waters off the Korean peninsula, we undertook a synthesis of results from past studies and data. Assuming that the growth coefficient K varies with water temperature, we derived a modified von Bertalanffy growth equation covering all life stages based on otolith analysis of anchovies collected from southwestern coastal area of Korea in 1996. By revisting a past study on spawning and egg production of anchovies in the southern Korean coastal waters, we calculated a monthly-averaged fraction of mature females spawning per day to estimate that an average female anchovy spawns 36 times per year, and that the mean number of eggs produced by an average female is ca. 160 × 10³ yr⁻¹. Accepting the ‘bigger-is-better’ hypothesis, we derived a theoretical mortality curve that assumes instantaneous natural mortality as an inverse function of anchovy body length. Assuming equilibrium status of stock, estimated annual instantaneous mortality of anchovy between egg to age-1 stage was 11.3 yr⁻¹ and estimated size-specific mortality was 1.24 d⁻¹ mm in fork length. The derived theoretical mortality curve fit well the stage-specific mortalities, which were estimated independently based on ichthyoplankton surveys and anchovy samples collected by commercial nets, but underestimated the egg mortality (0.89 d⁻¹ vs. 0.83 d⁻¹).     

Growth and survival response of the Catarina scallop Argopecten circularis (Sowerby) to stocking density and length of culture period

Growth and survival of the Catarina scallop, Argopecten circularis (Sowerby), were determined in relation to stocking density and length of culture period. Data were analysed by means of the von Bertalanffy growth equation and the weight-length allometric relationship. A mortality equation was empirically derived from the experimental data. Stocking density significantly affected both growth (P<0.05) and mortality parameters (P<0.01). The coefficients for the weight-length relationship. however, were not affected by stocking density. Mortality was highly variable, both during the culture period and between the different stocking densities. Two mortality patterns were identified. One was associated with post-spawning mortality and lower stocking rates. The other occurred at high densities where increased temperatures and overstocking provoked high mortalities and extremely divergent survival responses. The results showed that mortality, rather than growth, reflects more accurately the effects of density, and that better survival is not necessarily produced by stocking at the lowest rate.     

Extension of von Bertalanffy growth model incorporating growth patterns of soft and hard tissues in bivalve molluscs

ABSTRACT:   A new practical growth model through the partial reconstruction for the von Bertalanffy function (VBF) has been proposed. In numerous studies on various species, VBF has been recognized as an appropriate function to describe growth. Here the difference in growth dynamics between soft and hard tissues is considered using VBF. A differential equation in which the growth rates of these two tissue types are described, gives a four parameter model. This advanced model showed characteristics such as: (i) S-shape curve similar to the Gompertz model; (ii) unfixed point of inflection; and (iii) definition as an implicit function. The characteristic indicated in (iii) makes it impossible to apply the method of least squares to data analysis. Therefore, a solution was introduced combining Lagrange's method of indeterminate coefficients and the Newton method. Data analysis for verifying the performance of the advanced model was conducted on published data on growth of the bivalve Spisula sachalinensis . As a result of the comparison among the existing growth models, the advanced model produced the minimum value of Akaike information criterion (AIC).     

Age determination,growth, mortality and age of first reproduction in adult Queen Conch,Strombus gigas L., off Puerto Rico

Growth and mortality of adult Strombus gigas L. was studied in a population offshore of La Parguera, Puerto Rico. Adult queen conchs do not grow in shell length, but only in shell thickness. Growth in thickness of the flared shell-lip was measured during a 2-year mark-recapture study and modelled using the von Bertalanffy growth function. Model parameters were K=0.3706 year⁻¹ and L_∞ (asymptotic lip-thickness) =54.9 mm; the third von Bertalanffy parameter, t₀, cannot be obtained from mark-recapture data alone. Growth in tissue, meat and shell weights of adults were determined using the von Bertalanffy growth function in conjunction with regression equations for weights versus shell length and/or lip thickness. Total instantaneous mortality in adults, determined using von Bertalanffy parameters and lip-thickness frequency analysis, was 1.66 year⁻¹. Subtracting a previous estimate of fishing mortality (F=1.14 year⁻¹) yielded a natural mortality (M) of 0.52 year⁻¹. Given an average age at maturation, defined by the formation of the flared shell-lip, of 3.2 years, the age of first reproduction was estimated at 3.6 years, but could be as much as 4 years.     

Age, growth and life history of gunnel, Pholis fangi, in the Yellow Sea

We examined the formation of annuli by marginal observations on otoliths of gunnel (Pholis fangi) in the Yellow Sea to validate the age determination method and to derive the growth equation covering from larval to adult stages. Gunnels, ranging from 46 to 173 mm in total length, were collected by a bag net fishery from the western coastal waters off Korea from November 1998 to October 1999. Marginal observations indicated that the translucent zone (annual mark) on adult otolith was formed during the winter, whereas the opaque zone was formed during the summer. However, a translucent zone was formed between May and June in juvenile otoliths. This false ring was formed when the fish transited from the inshore pelagic life of larvae to the offshore bottom life of juveniles. The observed maximum age was 58 months. Using observed length-at-monthly age, growth in length was expressed by von Bertalanffy growth curve; L_t = 144.0 (1 − e^{−0.11 (t+0.43)}). P. fangi spawned in winter recruit to inshore, and grow quickly in the nursery habitats in spring. Gunnel inhabit the bottom offshore area during the summer season, and reappear inshore thereafter.     

基于科学调查与渔业生产数据的山东近海口虾蛄生长参数估算

渔业资源评估一般有两种数据来源,即科学调查数据和渔业生产数据;前者需要定期出海采样,耗时长且费用高,后者易于获取但样本代表性存在问题。本研究以山东近海口虾蛄为例,基于电子体长频率方法(ELEFAN)评估了口虾蛄的生长参数,采用bootstrap 重抽样方法比较了基于渔业生产数据与科学调查数据分析结果的差异,旨在探讨渔业生产数据在估算生长参数上的准确性。结果表明,科学调查数据估算得到的口虾蛄von Bertalanffy季节性生长方程中的极限体长L∞=193.16 mm, K=0.62,生产数据估算得到的口虾蛄极限体长L∞=171.70 mm,K=0.67;非参数检验表明基于两种采样方法所求得的口虾蛄的极限体长L∞呈现显著性差异, K 和“夏季点”ts 均呈现不显著性差异。本研究表明,渔业生产数据在一定程度上能够反映生物的生长状况,对K 和ts 的估算与科学调查数据估算的结果较为接近,但对极限体长的估算误差较大。因此口虾蛄生长研究需要依靠科学调查数据的支持,同时渔业生产数据可以作为辅助信息。