Tropical fish stocks are perceived not to exhibit seasonality in growth. For this reason the standard von Bertalanffy growth function (VBGF) has been used widely to fit the growth of tropical fish populations compared to the seasonally-oscillating VBGF (soVBGF), which is seldom used in tropical fisheries. To advocate for the use of the soVBGF in assessment of tropical fish stocks, this study compared the outputs of the two methods using ELEFAN_GA_boot on oysters from the Densu Delta, Ghana. Sampling of mangrove oyster, Crassostrea tulipa covered a period of 12 months and the data were analysed for VBGF growth parameters and its prediction models. The intensity of growth oscillation showed that C. tulipa exhibited seasonal growth (C = 0.50), and the soVBGF fitted the growth of the oyster better than the standard VBGF method. Estimates of some of the stock parameters (t_50, t_max, F_cur, E_cur and Y_cur) were comparatively higher for the standard VBGF than the soVBGF approach. In both approaches, the oysters were underexploited (E_cur < E_msy). However, unlike the soVBGF method where F_cur < F_0.5, the standard method indicated that F_cur > F_0.5. In view of the disparities, studies which adopt standard VBGF on tropical stocks that exhibit seasonality would likely generate comparatively higher outputs for relevant biological reference points, which may ultimately mislead management decisions. Given the sedentary nature of oysters which could render the organisms more susceptible to seasonal variations in environmental conditions to show seasonality as observed in this study, we recommend further works on tropical shell- and finfishes to corroborate the current findings or otherwise.

人们认为热带鱼类种群的增长没有季节性。因此，与热带渔业中很少使用的季节性波动的 VBGF (soVBGF) 相比，标准 von Bertalanffy 生长函数 (VBGF) 已被广泛用于拟合热带鱼种群的生长。为了提倡使用 soVBGF 评估热带鱼种群，本研究比较了使用 ELEFAN_GA_boot 对来自加纳 Densu Delta 的牡蛎的两种方法的输出。红树林牡蛎、Crassostrea tulipa 的采样涵盖了 12 个月的时间，并分析了 VBGF 生长参数及其预测模型的数据。生长振荡的强度表明，郁金香呈现季节性生长（C = 0.50)，soVBGF 比标准 VBGF 方法更适合牡蛎的生长。标准 VBGF的一些库存参数（t _50、 t _max、F _cur、E _cur和Y _cur）的估计值比 soVBGF 方法要高。在这两种方法中，牡蛎_都未得到充分开发（E _cur <  E _msy）。然而，与其中F _cur <  F _0.5的 soVBGF 方法不同，标准方法表明F _cur >  F _0.5. 鉴于这些差异，对表现出季节性的热带种群采用标准 VBGF 的研究可能会为相关生物参考点产生相对较高的产出，这最终可能会误导管理决策。鉴于牡蛎的久坐性质可能使生物体更容易受到环境条件季节性变化的影响，以显示本研究中观察到的季节性，我们建议对热带贝类和有鳍鱼类进行进一步的研究，以证实当前的发现或其他方面的发现。