Age determination of the grey mullet Mugil cephafus L. and the white mullet Mugif curema V. (Pisces: Mugilidae) in Tamiahua Lagoon, Veracruz

Abstract

RESUMENEn el presente estudio se establecen cinco y seis grupos de edad así como la relación edadlongitud, mediante el análisis del otolito sugitta de Mugif cephalus y M. curema, respectivamente, para la laguna de Tamiahua, Veracruz (México). Se describe la anatomía de escamas y otolitos para ambas especies. Las bandas de crecimiento rápido en los bordes indicaron que éste fue mayor en los meses de marzo a agosto y de julio a noviembre para M. cephalus y M. curemu, respectivamente. El desarrollo de dichas bandas se relacionó con la emigración de desove de ambas especies. Fueron calculadas las constantes del crecimiento de la ecuación de von Bertalanffy para ambas especies y sus sexos, utilizando la edad estimada por medio de escamas y otolitos. Se encontraron diferencias de crecimiento entre sexos, siendo éste mayor en las hembras que en los machos de ambas especies. Se concluye que tanto las escamas como los otolitos se pueden usar indistintamente en la determinación de la edad de los sexos de ambas especies; sin embargo, el mejor ajuste al modelo del crecimiento se obtiene utilizando la lectura de los otolitos.Palabras clave: escamas, otolitos, sugitta, Mugil cephalus. Mugil curemu, laguna de Tamiahua. ABSTRACTIn this study, by means of the sagittu otolith analysis, five and six age groups and the relation age-length of Mugil cephalus and M. curemu, respectively, in Tamiahua Lagoon, Veracruz (Mexico), are established. The anatomy of the scales and sugitta of both species is described. The fast growing bands on the edges show that their formation was higher from March to August for M. cephulus, and from July to November for M. curemu. The development of those bands was related to the spawning migration in both species. The constants of the growth equation of von Bertalanffy were calculated for the species and their sexes, using the scales and the otoliths. Differences in growth between sexes were detected; generally, the females reach a bigger size than the males at the same age in both mullet 329 http://dx.doi.org/10.7773/cm.v22i3.861Ciencias Marinas, Vol. 22, NO. 3, 1996 species. The scales and the otoliths may be used indistinctly in the age determination of both sexes of the species; nevertheless, the otolith showed a better tit to the growth equation.

Otolith micro- and macrostructure analysis to improve accuracy of growth parameter estimation for white mullet Mugil curema

“…An identical context exists when age 1 is concerned, as the lack of young-of-the-year specimens in samples leads to an overestimation of mean back-calculated sizes for both age 0 + and age 1. Comparing the ages estimated from the micro-and macrostructures on hake Merluccius merluccius, Gor- Ibáñez-Aguirre et al (1995, 1999 and Ibáñez-Aguirre & Gallardo-Cabello (1996) also obtained a mean back-calculated length of about 20.6 cm FL. This size is larger than that obtained in the present study (16.5 cm FL).…”

“…On the basis of scales for the same age class, Ibáñez-Aguirre & Gallardo-Cabello (1996) and Gallardo-Cabello et al (2005) estimated mean back-calculated lengths of 15.7 and 9.9 cm, respectively. An identical context exists when age 1 is concerned, as the lack of young-of-the-year specimens in samples leads to an overestimation of mean back-calculated sizes for both age 0 + and age 1.…”

“…Alvarez-Lajonchère (1981) and Ibáñez-Aguirre & Gallardo-Cabello (1996) demonstrated an annual formation of macrostructures coinciding with spawning in Cuba and Mexico. This pattern fits the present study as well, revealing that new macrostructures are deposited in the period from January to February, which closely follows the spawning period (November to February) (Santana da Silva 2007).…”

“…4). Thus growth curves from the present study and Richards & Castagna (1976) were the only ones to describe growth from the origin, whereas in Alvarez-Lajonchère (1981), Ibáñez-Aguirre & Gallardo-Cabello (1996), Ibáñez-Aguirre et al (1999) and Gallardo-Cabello et al (2005), the growth curve intercepts the y-axis at around 10 cm, which is well above the origin.The inclusion of fish of all sizes in age and growth studies results in a more representative growth curve for the species of interest across its entire life cycle as well as estimates of longevity and growth rate for different phases of development of white mullet. These estimates are particularly important for the calculation of biomass and recruitment in fisheries.…”

Age and growth of leaping grey mullet (<i>Liza saliens</i> (Risso, 1810)) in Minorca (Balearic Islands)

“…Although widely used, scale reading is difficult to apply because two annuli may appear yearly and sometimes the early annuli disappear as the fish grow (Quignard and Farrugio, 1981;Almeida et al, 1995, Ibañez-Aguirre et al, 1996. Otolith reading is difficult because the sagitta of older specimens often become too opaque (Erman, 1959;Kennedy and Fitzmaurice, 1969 ;Ibáñez-Aguirre et al, 1996). Bone reading is also not easy (Hickling, 1970).…”