Simões Sabrina M, Costa Rogerio C, Fransozo Adilson, Castilho Antonio L
Departamento de Ciências Biológicas, UNESP, Bauru, SP, Brasil.
An Acad Bras Cienc. 2010 Jun;82(2):369-78. doi: 10.1590/s0001-37652010000200013.
The objective of the present study was to analyze diel variation in the abundance and size of the seabob shrimp Xiphopenaeus kroyeri in the Ubatuba region, state of São Paulo, during the year 2000. In each season of the year, collections were made in the day and at night on 9 transects at depths ranging from 2 to 40 m. The estimated shrimp amount was of 28,878 individuals. Although the catch rate was higher during the day (15,853 shrimp), this did not differ significantly from the catch at night (13,025). The catch rate was higher in daytime on most transects, but was higher at night at locations where fine and very fine sand predominated. The majority of juveniles were caught during the day. The mean size (CL) was 14.43 +/- 4.02 mm for day and 14.82 +/- 4.28 mm for night samples, and the difference was significant (Student's t-test, df = 2, 429, t = 2.27, p = 0.02). The largest individuals were caught during the night. None of the three models that have been proposed in the literature to account for differences in the diurnal catch pattern of penaeid species can be applied to X. kroyeri. Our results provide evidence that sediment type not only influenced the catch rate in the analyzed periods, but also determined which models might fit the behavior of this species.
本研究的目的是分析2000年圣保罗州乌巴图巴地区的克氏海螯虾（Xiphopenaeus kroyeri）的丰度和大小的昼夜变化。在一年的每个季节，于白天和夜间在9个断面进行采集，深度范围为2至40米。估计虾的数量为28,878只。虽然白天的捕获率较高（15,853只虾），但与夜间捕获量（13,025只）相比并无显著差异。在大多数断面上，白天的捕获率较高，但在以细沙和极细沙为主的地点，夜间捕获率更高。大多数幼虾是在白天捕获的。白天样本的平均大小（头胸甲长度）为14.43±4.02毫米，夜间样本为14.82±4.28毫米，差异显著（学生t检验，自由度=2,429，t=2.27，p=0.02）。最大的个体是在夜间捕获的。文献中提出的用于解释对虾类物种昼夜捕获模式差异的三种模型，均不适用于克氏海螯虾。我们的结果表明，沉积物类型不仅在分析期间影响捕获率，还决定了哪种模型可能适用于该物种的行为。
