Spawning season, recruitment, and growth of the freshwater prawn Macrobrachium lamarrei (H. Milne-Edwards, 1837) in a perennial wetland, northeastern Bangladesh

Abstract

Spawning season, recruitment, and growth of the freshwater prawn Macrobrachium lamarrei were studied in a perennial wetland, northeastern Bangladesh during October 2016 to September 2017. Spawning season was estimated based on the monthly variations of percent ovigerous females. Recruitment and growth were estimated using the time series of the lengthfrequency distributions. We compared the von Bertalanffy growth function (VBGF) and the Pauly and Gaschütz growth function (PGGF) to identify any seasonal oscillation in growth rate. Ovigerous females occurred almost throughout the year, indicating a prolonged spawning season with two peaks between March-April (minor peak) and June-September (major peak). Both males and females with modal size ~ 8.0 mm carapace length first recruited in October, which synchronized with the major peak spawning season. There was seasonality in growth rate; hence, PGGF was adopted as the best-fitting model to describe the growth of both sexes. The estimated equations were L t = 17.86 (1-exp [-2.432 (t/ 12 -0.072) -(1.766/2π) sin {2π (t/ 12 -0.982)}] for males and L t = 23.18 (1-exp [-1.342 (t/ 12 + 0.106) -(0.388/2π) sin {2π (t/ 12 -0.209)}] for females. Sexual dimorphism was found with larger size in females than males. Longevity was estimated to be ~ 14 months for both sexes. These findings can be useful to formulate management measures for this prawn.

Estimation of Population Parameters of Glossogobius giuris in the Rabnabad Channel, Southern Bangladesh: Implications for Sustainable Management

“…In fact, this was not possible in this case, as the present study was based on fishery-dependent data. However, relatively high temperatures (23-33 • C) throughout the year at our study site may cause year-round spawning of this species, as reported by several studies [38,[71][72][73][74][75][76][77][78][79][80]. The spawning seasons of some gobiid species are summarized in Table 3.…”

“…The GSI showed that G. giuris could release eggs throughout the year with three peaks: two minor peaks in January-February and April-May, and a major peak occurring in August-November. The most vital environmental factors directly or indirectly influencing the reproduction of aquatic animals are temperature, rainfall, and photoperiod [68][69][70][71][72][73]. The seasonality of these factors also influences biological cycles by ensuring larval occurrence during the periods of available food [73,74].…”