Von Bertalanffy Parameters Research Articles

Age and growth of bluenose,Hyperoglyphe antarctica(Pisces: Stromateoidei) from the lower east coast, North Island, New Zealand

Abstract Growth of the bluenose, Hyperoglyphe antarctica (Carmichael, 1818) from the lower east coast, North Island, was determined by counting growth check rings in otoliths. One growth check ring appeared to be laid down each year, so this technique is probably valid for aging bluenose. Female fish had a significantly higher growth rate than males. Comparisons of samples from three sites indicated no significant regional differences in growth. The von Bertalanffy parameters L8,K, and t0 fitted to back‐calculated fish lengths were, respectively, 81.1 cm, 0.308, ‐0.627 for males, and 86.1 cm, 0.308, ‐0.384 for females.

Are Growth Parameters Estimated from Tagging and Age–Length Data Comparable?

The two most common ways of estimating fish growth use age–length data and tagging data. It is shown that growth parameters estimated from these two types of data have different meanings and thus are not directly comparable. In particular, the von Bertalanffy parameter l∞ means asymptotic mean length at age for age–length data, and maximum length for tagging data, when estimated by conventional methods. New parameterizations are given for the von Bertalanffy equation which avoid this ambiguity and better represent the growth information in the two types of data. The comparison between growth estimates from these data sets is shown to be equivalent to comparing the mean growth rate of fish of a given age with that of fish of length equal to the mean length at that age. How much these growth rates may differ in real populations remains unresolved: estimates for two species of fish produced markedly different results, neither of which could be reproduced using growth models. Existing growth models are shown to be inadequate to answer this question.

Age, growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico

The silky shark, Carcharhinus falciformis, and scalloped hammerhead, Sphyrna lewini, represent >80% of the shark by-catch of the winter swordfish/tuna longline fishery of the northwestern Gulf of Mexico. This catch represents a potential supplemental fishery, yet little is known of the life histories of the two species. This report relates reproductive biology data to age and growth estimates for 135 C. falciformis and 78 S. lewini. Unlike other regional populations, C. falciformis in the Gulf of Mexico may have a seasonal 12 month gestation period. Males mature at 210–220 cm TL (6–7 yr); females at >225 cm TL (7–9 yr). Application of age at length data for combined sexes produced von Bertalanffy growth model parameter estimates of L∞ = 291 cm TL, K = 0.153, t0 = −2.2 yr. Adult male S. lewini outnumbered adult females in catches because of differences in the distributions of the sexually segregated population. Males mature at 180 cm TL (10 yr); females at 250 cm TL (15 yr). von Bertalanffy parameter estimates for combined sexes of this species were L∞ = 329 cm TL, K = 0.073, to = −2.2 yr.

Age and Growth, Movements and Distribution of the Cownose Ray, Rhinoptera bonasus, in Chesapeake Bay

Ages were estimated for 115 of 899 cownose rays,Rhinoptera bonasus, collected primarily from commercial fishing gear, in lower Chesapeake Bay and vicinity from May through October, 1976–78. Age determinations were made using sectioned vertebral centra and estimates of von Bertalanffy parameters were for males DW∞=119.2, K=0.126, and t0=−3.699, and for females DW∞=125.0, K=0.119, and t0=−3.764. Females attained a larger adult size and the oldest specimen aged was a female 13 years old and 107 cm disc width. Both sexes mature after reaching about 70% of their maximum size and ages at maturity were estimated at 5 to 6 years for males and 7 to 8 years for females. In spring migrating rays schooled by size; they arrived along the North Carolina coast by April and entered Chesapeake Bay by early May. Rays were abundant in the major Virginia tributaries of Chesapeake Bay throughout summer and occurred in salinities as low as 8‰ and at water temperatures between 15–29 °C. Size segregation continued during summer and adults schooled by sex. Most rays left Chesapeake Bay by early October.

Growth and population dynamics of the Indian white prawnPenaeus indicus H M Edwards from Kakinada

The von Bertalanffy parameters of growth inPenaeus indicus are estimated as L∞=218·9 mm,K=2·0 per year, andt0=0·01 year in females and 227·2 mm, 1·8 per year and −0·0729 year, respectively in males. The instantaneous rates of mortality are estimated asZ=9·42,M=3·30 andF=6·12 in females and 12·73, 2·90 and 9·83, respectively in males. Various morphometric and length-weight relationships are worked out. At the current rate of fishing, the yield in weight per recruit is 23·05 g in females and 31·74 g in males. There is scope to increase the yield of this species by increasingF (i.e. effort).

Age and Growth of the Sandbar Shark (Carcharhinus plumbeus) from the Western North Atlantic

Age and growth of the sandbar shark (Carcharhinus plumbeus) was determined from rings in the vertebrae of 475 individuals, tagging data from 220 sharks at liberty for up to 17 yr, and length–frequency data from 2594 individuals. The oldest male sandbar aged in this study was 15 yr old and 154 cm fork length (FL); the oldest female was 21 yr old and 204 cm FL. The sexes grew at similar rates, 5.2–7.3 cm/yr. Females reached a larger adult size. Age to maturity was estimated at 13 yr in males and 12 yr in females. Tag returns indicated that sandbar sharks may live for over 30 yr. von Bertalanffy parameters for males are L∞ = 257, K = 0.0501, t0 = −4.5 and for females are L∞ = 299, K = 0.040, t0 = −4.9.

Growth of Tagged American Lobsters, Homarus americanus, in the Bay of Fundy

Sphyrion-tagged lobsters recaptured in the Bay of Fundy during 1977–80 yielded mean annual molt increment and molt probability data for male and female lobsters of 60–171 mm carapace length from which growth curves were calculated. In addition, a multiple regression model was used to generate growth curves from premolt size, number of molt periods lobsters were exposed to, and growth increment data for 850 tagged lobsters at liberty for 1–5 yr. Von Bertalanffy parameters were calculated from these empirical growth curves, which suggest that lobsters take 20–35 yr from time of hatching to reach 200 mm carapace length in the Bay of Fundy. Analysis of pleopods indicated that the majority of lobsters molt during August–October each year. Growth per molt of immature (60–94 mm carapace length) and mature (95–170 mm carapace length) male and immature female lobsters was arithmetic (regression slope 1.04) but was regressive for mature females (slope 0.95). Mature lobsters molted less frequently than immature lobsters, but mature males grew more rapidly than mature females. Most mature females in the Bay of Fundy are on a 2-yr molt–reproductive cycle. About 20% of ovigerous females recaptured within 2 yr after release had extruded eggs a second time without molting, confirming that multiple egg extrusions between molts do occur naturally.

Growth rates of barramundi, Lates calcarifer (Bloch), in Papua new Guinea

Growth rates of L. calcarifer in western Papua were determined using modal progression in length- frequency samples and analysis of increases in lengths of tagged fish. Growth was rapid, the Von Bertalanffy parameters being K = 0.128, L∞ = 138 cm and t0 = -1.12 years. The length-weight relationship was W = 0.0106l3.02, where W is weight measured in grams and I is length measured in centimetres.

Observations on some population parameters of exploited stocks of Senilia senilis (=Arca senilis) in Sierra Leone

The West African cockle Senilia senilis (L.) (=Arca senilis L., 1758) from some estuaries and muddy shores of Sierra Leone was studied from September, 1973 to February, 1975. Quantitative samples were obtained along transects using quadrats and sieves; some random hand-picked collections were also made. The length, number of rings and the maximum width of the inter-ring bands along the outer convex surface of the right valve were recorded from samples of ≥25 specimens. All the cockle beds examined were exploited and had stocks with a mean density of ≤9 large (>10 mm) cockles/m2, and at River No. 2 estuary at peak spatfall, of 130 seed cockles/m2. Spat settlement began in November-December after the rainy season, reached a peak in January-February and continued to the early part of the following rainy season (May-June). Seed cockles were absent from August to October. In the length-frequency distributions, modes were clear and associated with certain shell-ring numbers. Rings on shells were formed once a year, during July to September, the period of maximum rainfall, and they were successfully used in ageing the cockles. The first ring was formed at a mean age of 7 months and the subsequent ones annually. The growth period of the inter-ring bands, considered to extend from August to the following July (s. senilis growth year), may actually be of only 10 months duration. Sublittoral cockles from No. 2 estuary showed a higher growth rate than those from the levels exposed at low tide and subjected to greater exploitation. Cockles from the Sierra Leone River Estuary showed even greater growth. s. senilis grows slowly and lives long (up to 8 to 9 years), and its von Bertalanffy parameters are: River No. 2 estuary cockles →k=0.27 to 0.31 and L ∞=99 mm; Sierra Leone River Estuary cockles →k=0.22 and L ∞=145 mm. At No. 2 estuary, cockles enter the fishery at 22 to 25 mm (14 to 15 months old) and exploitation is heavy, resulting in the stocks being dominated by a few young year-classes.

Preliminary estimates of age of the bronze whalerCarcharhinus brachyurus(Chondrichthyes: Carcharhinidae) from southern Africa, with a review of some life history parameters

Counts of growth bands in sectioned vertebral centra were used to estimate the ages of 61 bronze whalers Carcharhinus brachyurus collected between March 1984 and June 1988 from southern Africa. Estimates of Von Bertalanffy parameters for the observed data were: L ∞ = 384,8, K = 0,0385, t 0 = −3,477. The t0 value overestimates the gestation, which is thought to be between 8 and 24 months. Growth in bronze whalers appears to be slower than in any Carcharhinus spp. previously studied. Maximum size recorded during this study was 294 cm total length (TL) for a male and 288 cm TL for a female, and the maximum ages recorded were 30 and 25 years respectively. Age at sexual maturity has been calculated at 13–19 years for males and 19–20 years for females. Differential mortality rates appear to operate on juveniles (Lee's phenomenon). Arguments are presented that indicate two separate populations: one distributed from the Western Cape eastwards and the other from just south of Walvis Bay northwards. The slow growth...