Distribution and abundance of zoeae I (Crustacea, Brachyura) on a coral reef in the southwest Gulf of Mexico

Abstract In this study we analyze both seasonal and inter-annual variations in the community parameters of Brachyura zoea I in the Parque Nacional Sistema Arrecifal Veracruzano. Planktonic samples from four transects were collected during three weather conditions: cold fronts; rainy and dry conditions in 2011 and 2012; and cold fronts and dry conditions in 2013. We measured temperature, salinity, and dissolved oxygen, in situ, to determine whether these parameters could explain the observed variations in the community patterns of brachyuran zoea I. We collected zoeae I of 18 species of brachyurans. The dominant species were Libinia dubia H. Milne Edwards, 1834; Menippe nodifrons Stimpson, 1859; and Callinectes sapidus Rathbun, 1896. The temperature and dissolved oxygen were the highest during the rainy conditions and the salinity during the dry conditions in the southern transects. The highest species richness (14) and diversity (2.97 bits individual-1) were found in central transects during cold front conditions. However, we found the highest species richness and diversity during the dry conditions, in the southern transects. Libinia dubia presented the highest density during cold fronts with 1592 ± 127 zoeae 100 m−3 in the northern transect, followed by C. sapidus in the north-central transect, this was observed for both species in the offshore zone. In conclusion, the parameters of the community of zoea I were influenced by the physical parameters measured in each sampling zone.

摘要 本研究针对韦拉克鲁斯珊瑚礁系统国家公园内短尾下目（Brachyura）I期状幼体（zoea I）的群落参数，分析其季节与年际变化特征。研究于2011、2012年的冷锋、雨季、旱季以及2013年的冷锋与旱季期间，在4条断面采集浮游生物样本；现场测定水温、盐度与溶解氧，以探究上述环境参数能否解释短尾类I期状幼体群落格局的观测变异。本次研究共采集到18种短尾类的I期状幼体，优势物种为1834年H. Milne Edwards记述的宽大蜘蛛蟹（Libinia dubia H. Milne Edwards, 1834）、1859年Stimpson记述的结节哲蟹（Menippe nodifrons Stimpson, 1859）以及1896年Rathbun记述的蓝蟹（Callinectes sapidus Rathbun, 1896）。南部断面的水温与溶解氧在雨季达到最高值，盐度则在旱季达到峰值。冷锋期间，中部断面的物种丰富度（14种）与多样性（2.97比特·个体⁻¹）为最高；但旱季南部断面的物种丰富度与多样性亦达到峰值水平。宽大蜘蛛蟹的密度在冷锋期间达到最高，北部断面为1592±127只·100 m⁻³；其次为北中部断面的蓝蟹，该分布模式在近海区域两类物种中均有体现。综上，短尾类I期状幼体的群落参数受各采样区域实测的物理环境参数显著影响。