Models of Mytilus growth, based mostly on length-at-age data, have typically taken the form exemplified by the von Bertalanffy or Gompertz formulations. These models require assumptions about the form of the growth curve. We used the Schnute general growth model to examine growth in the Pacific Blue Mussel, Mytilus trossulus, in Prince William Sound, AK. The Schnute model provides a convenient analytical method for selecting among all previously published growth models. Mussels were tagged with individually numbered tags at 13 sites in July 1997 and were collected in July 1998. Age was determined from surface growth rings on the shell, and shell length at maximum annulus was measured. Annual deposition of the growth rings was verified through radial sections of mussel valves, aided by acetate peels, in conjunction with in situ annual growth measurements. Growth was modeled with the Schnute general growth model for age-length data or with an analog of the Schnute model for growth-increment data. Bootstrap confidence intervals were obtained for all parameters of the model and for model predicted lengths at each annulus. Confidence intervals of the between-annuli growth-increment model overlapped those of the age-length model at all annuli when growth over the entire range of ages in the population was estimated. Differences in growth model parameters between the age-length model and the mark-recapture analog could be accounted for solely by inherent differences in age-based versus length-based models. Growth estimates generated from between-annuli measurements were equivalent to growth estimates obtained from mark-recapture measurements of annual growth. In general, mussel growth at our sites was best described by the von Bertalanffy submodel.

中文翻译：

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太平洋蓝贻贝, Mytilus trossulus Gould, Schnute 型的年龄长度和生长增量一般生长模型的比较

贻贝生长模型主要基于年龄数据，通常采用 von Bertalanffy 或 Gompertz 公式例示的形式。这些模型需要对增长曲线的形式进行假设。我们使用 Schnute 一般生长模型研究了位于阿拉斯加州威廉王子湾的太平洋蓝贻贝 Mytilus trossulus 的生长情况。Schnute 模型提供了一种方便的分析方法，可以在所有以前发布的增长模型中进行选择。贻贝于 1997 年 7 月在 13 个地点用单独编号的标签进行标记，并于 1998 年 7 月收集。年龄由壳上的表面年轮确定，并测量最大环带处的壳长度。通过贻贝瓣的径向截面，在醋酸盐皮的帮助下，证实了年轮的年度沉积，结合原位年生长测量。使用年龄长度数据的 Schnute 一般生长模型或生长增量数据的 Schnute 模型的模拟来模拟生长。获得模型的所有参数和每个环的模型预测长度的 Bootstrap 置信区间。当估计人口在整个年龄范围内的增长时，环间增长增量模型的置信区间与所有环的年龄长度模型的置信区间重叠。年龄-长度模型和标记-重新捕获类似物之间生长模型参数的差异可以完全由基于年龄的模型与基于长度的模型的固有差异来解释。从年间测量产生的增长估计相当于从年度增长的标记-重新捕获测量获得的增长估计。一般而言，von Bertalanffy 子模型最好地描述了我们地点的贻贝生长。