scholarly journals EVALUACIÓN POBLACIONAL DEL STOCK EXPLOTABLE DEL COMPLEJO OPISTHONEMA (PISCES: CLUPEIDAE) EN EL GOLFO DE NICOYA, COSTA RICA

2010 ◽  
Vol 2 ◽  
pp. 83 ◽  
Author(s):  
Luis A. Vega Corrales
Keyword(s):  
Costa Rica ◽  
Growth Parameters ◽  
Gonadosomatic Index ◽  
Fishing Effort ◽  
Reproductive Pattern ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Von Bertalanffy Model ◽  
First Maturity ◽  
Size At First Maturity

El género Opisthonema sustenta la pesquería de sardina en Costa Rica. Esta investigación se orientó hacia la evaluación poblacional del stock explotable de esta pesquería en el Golfo de Nicoya. Las muestras mensuales fueron recolectadas desde junio del 2007 hasta mayo del 2008. Se determinó el patrón de reproducción de O. libertate y se estimaron los parámetros de crecimiento de las curvas en longitud del modelo de von Bertalanffy para O. libertate y O. medirastre. Con base en el índice gonadosomático, O. libertate desova intensamente durante la época más calurosa del año, entre febrero y mayo. La talla de primera madurez (TPM50%) fue de 18.68 cm de LT. La ecuación de crecimiento de von Bertalanffy estimada para O. libertate fue: Lt= 25.9 [1–exp–1.03(t+0.13)] y para O. medirastre: Lt= 32.0 [1–exp–1.10(t+0.15)]. El reclutamiento máximo de la pesquería de O. libertate ocurre entre septiembre y noviembre. Esta especie muestra un índice de explotación (E) de 0.65 y O. medirastre de 0.55. Se nota una mejoría en el E comparado con estimaciones anteriores. Se recomienda como medida de manejo para esta pesquería ajustar la época de veda y no incrementar el esfuerzo pesquero.The Opisthonema genus supports the sardine fishery in Costa Rica. This research was directed to population assessment of the exploitable stock of this fishery in the Golfo of Nicoya. Monthly samples were collected since June, 2007 until May, 2008. The reproductive pattern of O. libertate were determined and growth parameters of curves in the length of O. libertate and O. medirastre were estimated using the von Bertalanffy model.. Based on the gonadosomatic index, O. libertate spawn intensively during the hottest time of the year, between February and May. The size at first maturity (SFM50%) was 18.68 cm T.L. The growth equation of von Bertalanffy was estimated for O. libertate: Tl= 25.9 [1–exp–1.03(t+0.13)] and O. medirastre:  Tl= 32.0 [1–exp–1.10(t+0.15)]. The maximum recruitment to the fishery of O. libertate occurs between September and November. This species show an exploitation index (E) of 0.65 and O. medirastre have an E value of 0.55. It is note an improvement in the E value, as compared to previous values. It is recommended as management measure to adjust the close season, and to avoid any increment of the fishing effort.  

Movements and growth of tagged Blue Endeavour Prawns, Metapenaeus endeavouri (Schmitt 1926), in the Western Gulf of Carpentaria, Australia

1992 ◽  
Vol 43 (5) ◽  
pp. 1283 ◽  
Author(s):  
RC Buckworth
Keyword(s):  
Growth Parameters ◽  
Fishing Effort ◽  
Parameter Estimates ◽  
Von Bertalanffy ◽  
Length Frequency ◽  
Von Bertalanffy Model ◽  
The Mean ◽  
Adult Habitat ◽  
Mean Time ◽  
Length Frequency Data

Mark-recapture experiments, conducted near Groote Eylandt in the western Gulf of Carpentaria during 1984, were used to examine movements and growth of blue endeavour prawns, Metapenaeus endeavouri. The mean distance moved by tagged animals was only 12.7 (s.e.�1.0) km, but a few were recaptured > 100 km from their release sites. The mean time at liberty was 36.8 (�1.6) days, the maximum being 155 days. The distance and speed of movements were not related to the size or sex of tagged prawns. Nonuniform recapture patterns corresponded largely with fishing effort. Recaptures per unit effort (R/f analyses), used to account for nonuniform fishing effort, indicated that there was no directionality in movements. Thus, tagged specimens of M. endeavouri dispersed slowly across suitable adult habitat, with limited intermixing of adults from stocks around Groote Eylandt. Estimates of the von Bertalanffy growth parameters L∞ and K for each sex were obtained for data from summer and winter releases. The fit of the von Bertalanffy model to summer data was limited by the small number of recaptures. The fit of the model to winter data was improved by removing early recaptures, and these estimates are presented as the primary descriptors of growth in M. endeavouri. Parameter estimates did not differ significantly between seasons, but L∞ differed between sexes and K differed between sexes in winter. Predicted growth corresponded to the progression of modes in length-frequency data from commercial catches.

Demography of the Agassiz's parrotfish Sparisoma frondosum (Agassiz, 1831) in north-eastern Brazil

2015 ◽  
Vol 96 (5) ◽  
pp. 1157-1166 ◽  
Author(s):  
Rosângela Lessa ◽  
Camila R. Da Silva ◽  
June F. Dias ◽  
Francisco M. Santana
Keyword(s):  
Growth Parameters ◽  
Growth Curves ◽  
Information Criterion ◽  
Age And Growth ◽  
Von Bertalanffy ◽  
Eastern Brazil ◽  
North Eastern ◽  
Marginal Increment ◽  
First Maturity ◽  
Size At First Maturity

Age and growth of Agassiz's parrotfish Sparisoma frondosum captured off Brazil (Pernambuco) were estimated using sagittal otoliths from 251 specimens. Sex of each specimen was determined and showed that 130 specimens were females (13.1 to 36.8 cm TL) and 121 were males (17.5 to 36.6 cm TL). The otolith marginal increment analysis indicated a single translucent ring formed every year. Parameters of growth curves were derived for the von Bertalanffy (VBGF) and Gompertz models. Based on the Akaike information criterion (AIC), both models were suitable for describing the growth of this species. VBGF parameters were estimated for males L∞ = 39.74 cm TL, K = 0.22, t0 = −1.63 years, females L∞ = 32.38 cm TL, K = 0.44; t0 = −0.23 years; and for the sexes combined L∞ = 33.66 cm TL, K = 0.41, t0 = −0.27 years. The study showed that 55% of individuals were 3 and 4 years of age, with maximal age of 9 years. Mature females (>17.6 cm TL) accounted for 45% of the sample. The age at first maturity for females was 1.6 years. For males the size at first maturity was not determined as immature individuals were not present in the overall sample. Also, primary males (PM) and specimens with gonads undergoing sexual transition were not found. The age structure and growth parameters for S. frondosum are an important contribution to the assessment of the state of exploitation of this species.

scholarly journals Age estimation, growth and maturity of the European hake (Merluccius merluccius (Linnaeus, 1758)) from Iberian Atlantic waters

2003 ◽  
Vol 60 (5) ◽  
pp. 1086-1102 ◽  
Author(s):  
C Piñeiro ◽  
M Saínza
Keyword(s):  
Life History ◽  
Age Estimation ◽  
Growth Parameters ◽  
Grey Literature ◽  
Von Bertalanffy ◽  
Merluccius Merluccius ◽  
Consistent Manner ◽  
The Mean ◽  
First Maturity ◽  
European Hake

Abstract Difficulties in age estimation for hake (Merluccius merluccius) have hampered the assessment of stocks. Here, we describe new, agreed ageing criteria based on the interpretation of the pattern of otolith growth. Improved estimates of von Bertalanffy growth parameters, and new estimates of maturity ogive parameters and length–weight relationships for European hake from Iberian Atlantic waters are presented. The results came from a study carried out during 1996–1997 and provide the first published account of the main life history traits of Southern stock hake. von Bertalanffy growth parameters of males were L∞ = 70cm, K = 0.18 year−1, and t0=−0.97 year, and those of females were L∞ = 89cm, K = 0.13 year−1, and t0 = −1.15 year. Growth of sexes differed from age 3 onwards, with females being on average larger and heavier than males. The estimated total length (L, cm)–total weight (W, g) relationships were W=0.0132135L2.8134246 for males and W=0.0086471L2.942563 for females. Spawning took place from December to May with a peak in February. The mean length and age at first maturity were 32.8 cm at 2.5 years for males and 45 cm at 4.4 years for females. Application of new ageing criteria showed that otolith sections may be used to determine ages up to 5 years in a consistent manner. These results indicate that hake of the Southern stock grow at higher rates and mature earlier than previously considered. Summaries of hake's life history parameters from other marine regions are also presented in order to make information that belongs largely to the grey literature available.

scholarly journals Stock dynamics of the brushtooth lizardfish Saurida undosquamis (Richardson, 1848) from a tropical multispecies fishery in the southeastern Arabian Sea

2019 ◽  
Vol 32 ◽  
pp. 9
Author(s):  
Theparambil Mohamed Najmudeen ◽  
Pallangattu Kochukandan Seetha ◽  
Payiyappanal Ulahannan Zacharia
Keyword(s):  
Arabian Sea ◽  
Growth Parameters ◽  
Total Mortality ◽  
Fishing Effort ◽  
Reference Points ◽  
Trophic Levels ◽  
Southeastern Arabian Sea ◽  
Eastern Arabian Sea ◽  
The Mean ◽  
First Maturity

The brushtooth lizardfish Saurida undosquamis (Richardson, 1848) is a high trophic level benthic predator and is one among the most exploited demersal finfish species from eastern Arabian Sea by Indian trawlers. However, in recent years, the landings of many top predator fishes including S. undosquamis showed a declining trend resulting in a steady decline in the mean trophic levels of the fishes caught commercially in the region. We investigated the growth, mortality and stock dynamics of S. undosquamis harvested by mechanised trawls in the southeastern Arabian Sea, using length-based methods for the data collected during 2012–2016. Besides, Bayesian state-space implementation of the Schaefer model (BSM) and catch-based MSY (CMSY) estimation were also made using the data for the period 1985–2016. Total length of the fish ranged from 5.5 to 34.5 cm with average annual mean length of 22.0 cm during 2012–2016. The growth parameters L∞ and K were 37.3 cm and 0.41 year−1, respectively. The natural, fishing and total mortality coefficients were 0.92, 2.58 and 3.5, respectively and exploitation ratio was 0.82. The length at first maturity was estimated at 21.4 cm for females. The mean size in the catch is lower than the optimum length for exploitation. Fisheries reference points (MSY, Fmsy, Bmsy) as well as relative stock size (B/Bmsy) and exploitation (F/Fmsy) estimated from catch data and broad priors for resilience (r), implies an exploitation of 30% below Bmsy level. Results from the length-based Thompson and Bell prediction model indicates that reducing the present level of fishing effort by 40% would lead to a harvest of the species at a sustainable level. As “fishing down food web” is reported in recent years from eastern Arabian Sea, the exploitation of top predators need to be maintained at sustainable levels to prevent ecosystem changes along the region.

Aspects of the reproductive cycle and gonadal development of Murray cod, Maccullochella peelii peelii (Mitchell) (Percicthidae), in Lake Charlegrark and adjacent farm ponds, Victoria, Australia

1995 ◽  
Vol 46 (4) ◽  
pp. 723 ◽  
Author(s):  
GJ Gooley ◽  
TA Anderson ◽  
P Appleford
Keyword(s):  
Gonadosomatic Index ◽  
Testicular Tissue ◽  
Gonadal Development ◽  
Testicular Development ◽  
Male Fish ◽  
Farm Ponds ◽  
Macroscopic Classification ◽  
First Maturity ◽  
Murray Cod ◽  
Size At First Maturity

The gonadal development of Murray cod, Maccullochella peelii peelii, in Lake Charlegrark, Victoria, and adjacent farm ponds was evaluated. Gonadosomatic index, macroscopic classification and histological analysis were used to determine the age at first maturity and the gonadal development in this introduced population. There is a marked difference between the sexes in the size at first maturity, with females maturing at approximately 6 years of age and 2000 g in weight and males maturing at 3-4 years and 700 g. Gonadosomatic index data indicate that spawning occurs around November. Ovarian development in this species follows a pattern similar to that in a number of other teleosts. Testes have a lobular structure. Macroscopic evaluation of ovaries provided a good indication of the stage of the development of the gonad. However, the presence of spermatozoa throughout the year in the gonads of mature male fish makes the macroscopic evaluation of testicular development less reliable. Three cod, approximately 1% of the population, contained gonads with both ovarian and testicular tissue.

scholarly journals Two-step Procedure Based on the Least Squares and Instrumental Variable Methods for Simultaneous Estimation of von Bertalanffy Growth Parameters

2019 ◽  
Vol 10 (2) ◽  
pp. 49-81 ◽  
Author(s):  
Ivelina Yordanova Zlateva ◽  
Nikola Nikolov
Keyword(s):  
Least Squares ◽  
Instrumental Variable ◽  
Initial Conditions ◽  
Growth Parameters ◽  
Individual Growth ◽  
Simultaneous Estimation ◽  
Parameter Estimates ◽  
Growth Equation ◽  
Von Bertalanffy ◽  
Step Procedure

Advanced in the present article is a Two-step procedure designed on the methods of the least squares (LS) and instrumental variable (IV) techniques for simultaneous estimation of the three unknown parameters L∞, K and t0, which represent the individual growth of fish in the von Bertalanffy growth equation. For the purposes of the present analysis, specific MATLAB-based software has been developed through simulated data sets to test the operational workability of the proposed procedure and pinpoint areas of improvement. The resulting parameter estimates have been analyzed on the basis of consecutive comparison (the initial conditions being the same) between the results delivered by the two-step procedure for simultaneous estimation of L∞, K and t0 and the results obtained via the most commonly employed methods for estimating growth parameters; first, use has been made of the Gulland-and-Holt method for estimating the asymptotic length L∞and the curvature parameter K, followed by the von Bertalanffy method for estimation of t0.

Age, growth and reproductive biology of the saddled seabream (Oblada melanura) in the North Aegean Sea, Eastern Mediterranean

2020 ◽  
Vol 49 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Ismail Burak Daban ◽  
Ali Ismen ◽  
Mukadder Arslan Ihsanoglu ◽  
Koray Cabbar
Keyword(s):  
Growth Parameters ◽  
Eastern Mediterranean ◽  
Length Distribution ◽  
Total Mortality ◽  
Aegean Sea ◽  
Growth Equation ◽  
Weight Relationship ◽  
The North ◽  
North Aegean Sea ◽  
First Maturity

AbstractThis study determines the length distribution, length– weight relationship, age, growth parameters, mortality rate, sex ratios, length at first maturity and reproduction of saddled seabream (Oblada melanura) collected monthly by fishermen around the Northern Aegean Sea between November 2017 and October 2018. The length–weight relationship was calculated as W=0.0091×L3.11 (R2=0.95) and positive allometric growth was found. The condition factor and GSI varied between 0.81–1.58 and 0.01–9.61, respectively. The spawning season extended from May to July and peaked in June. Total lengths at 50% maturity were 18.97 cm for males and 18.83 cm for females. Parameters of the von Bertalanffy growth equation were: L∞ =29.91 cm, K =0.27 per year, t0 =−0.82 year and age varied between 1 and 8. The instantaneous rates of total mortality (Z) and natural mortality (M) were 1.36 and 0.58 per year, respectively. Rates for fishing mortality F and exploitation E were 0.78 and 0.57 per year, respectively. The mean absolute fecundity (F) was 117 075±23 243 oocytes, ranging from 19130 to 470 132.

Age, growth and mortality of the garfish, Belone belone (L. 1761) in the Adriatic Sea

2012 ◽  
Vol 93 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Barbara Zorica ◽  
Vanja Čikeš Keč
Keyword(s):  
Adriatic Sea ◽  
Growth Parameters ◽  
Fork Length ◽  
Mortality Rates ◽  
Von Bertalanffy ◽  
Positive Allometry ◽  
Von Bertalanffy Model ◽  
Total Length ◽  
Belone Belone ◽  
Conservation And Management

A sample of 3393 garfish, Belone belone (Linnaeus, 1761) was captured using a seine net between January 2003 and December 2008, along the eastern Adriatic Sea. The range in total length was 20.8–75.4 cm and in weight was 12.21–639.25 g. Length–length equations for converting size measurements (standard length and fork length to total length (TL)) were linear. In the length–weight relationship, positive allometry was established (b = 3.4818). Age, determined from sagittal otoliths, ranged from 1+ to 8+ years. The estimated von Bertalanffy model growth parameters for garfish were L∞ = 90.3 cm, K = 0.158 year−1, t0 = −0.109. Otolith weight was endorsed as a possible age predictor, as it showed highly exponential correlation with total garfish length and age (Wo = 0.0012 TL2.189; Wo = 0.568t1.486). These findings were used to examine mortality rates and exploitation in order to improve conservation and management of this pelagic species.

scholarly journals Structure and population dynamics of the secondary burrower crayfish Procambarus acanthophorus from a tropical Mexican wetland

2016 ◽  
Vol 94 (7) ◽  
pp. 479-488
Author(s):  
J.A. Viccon-Pale ◽  
P. Ortega ◽  
L. Mendoza-Vargas ◽  
P. Castilla-Hernández ◽  
A. López-Cuevas ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Growth Parameters ◽  
Von Bertalanffy ◽  
Frequency Distributions ◽  
Structure And Dynamics ◽  
Von Bertalanffy Model ◽  
Cephalothorax Length ◽  
Flood Period ◽  
Class Dynamic

Catch size, sex ratio, structure and dynamics, as well as mortality, of a population of the secondary burrower crayfish Procambarus acanthophorus Villalobos, 1948, from tropical wetland La Mixtequilla, Veracruz, Mexico, were examined. Monthly samples were taken from artisanal commercial captures. A total of 2141 individuals were caught. Although the total female:male ratio was 0.86, variation in sex ratios have also been found in monthly catches. Monthly polymodal frequency distributions of cephalothorax length (CL) were analyzed by the Bhattacharya method. Population catches consisted of six CL classes. The CL-class dynamic may show adaptations to the flood period. Growth parameters were estimated using the von Bertalanffy model. For females, K = 0.39 year−1, CL∞ = 57.30 mm, [Formula: see text] = 3.11, and tmax = 6.73 years were found; it is appropriate that for males, K = 0.40 year−1, CL∞ = 59.00 mm, [Formula: see text] = 3.14, and tmax = 6.59 years were found. We also examined whether water temperature influences the catches or sex ratio.

scholarly journals Reproductive Biology of Coral Catshark Atelomycterus marmoratus (Anonymous [Bennett], 1830) in Seribu Islands, Indonesia

2019 ◽  
Vol 20 (8) ◽  
Author(s):  
Selvia Oktaviyani ◽  
WANWAN KURNIAWAN ◽  
FAHMI
Keyword(s):  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Maturity Stage ◽  
Total Length ◽  
Mean Size ◽  
The Mean ◽  
First Maturity ◽  
The Relationship ◽  
Monthly Variations ◽  
Size At First Maturity

This study provides information on the reproductive biology of the coral catshark caught in the waters around Seribu Islands, Indonesia. A total of 257 coral catsharks were collected from February 2017 to January 2018. The total length of coral catshark ranged from 170 to 585 mm for females and 255-575 mm for males, respectively. The total weight of females ranged from 85 to 640 g and males from 100 to 620 g The sex ratio between females and males was 0.45 and it was not significantly different from the expected 1:1 ratio. The growth pattern of coral catsharks in Seribu Island was negatively allometric and the population was dominated by mature sharks. The mean size at first maturity was estimated to be 557 mm for females and 514 mm for males, based on to the relationship between the proportion between maturity stage and total length. The ovulation season was estimated occur from October to March, whereas September to April was mating season based on monthly variations of gonadosomatic index (GSI) values and the occurrence of egg cases in uterus.

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