Baali Ayoub, Bourassi Hajar, Falah Samira, Abderrazik Wahbi, Manchih Khalid, Amenzoui Khadija, Yahyaoui Ahmed
Laboratory of Zoology and General Biology, Faculty of Science, Mohammed V University, Rabat, Morocco.
Laboratory of Environment and Aquatic Ecology, Faculty of Science Ain Chock, Hassan 2 University, Casablanca, Morocco.
Pak J Biol Sci. 2017;20(4):165-178. doi: 10.3923/pjbs.2017.165.178.
Sardinella sp. has gained much attention lately because of its biomass increase, which might be the result of climatic changes occurring across the Atlantic sea. Little information is known about reproduction of these species particularly in the Moroccan Atlantic area. The objective of the this study was to explore some aspects of the reproductive biology of Sardinella in the South of Atlantic Moroccan coast.
Monthly samples were collected during the period between February, 2015 and January, 2016 in the area between Cape Boujdor and Cape Blanc. The data collected concerned the measure of the total length, the weight, the gonad weight as well as the sex and maturity stages. The χ2 test was used to compare the differences between both sexes and the ANOVA test was adopted to analyze the data variation.
Sardinella sp. is a gonochoristic fish. The overall female to male ratio was not statistically different for both species (χ2 = 0.68 for Sardinella aurita and χ2 = 1.04 for Sardinella maderensis), although it varied seasonally and according to the length of the fish. The monthly changes in the gonadosomatic index and the macroscopic characteristics of gonads showed that round Sardinella in the South of Morocco spawns between February and July and between November and December with a spawning peak on April. For the flat Sardinella, it spawns between February and March and in July with a spawning peak on July. Females round Sardinella reach first sexual maturity at a smaller size than males (26.17 and 26.78 cm, respectively). Concerning the flat Sardinella, it was the opposite. Males reaching sexual maturity are smaller than females (20.75 and 21.76 cm, respectively).
It is concluded that the size at first maturity revealed that mature females in the South of Moroccan Atlantic Ocean were smaller than males for the round Sardinella and the opposite was observed for the flat Sardinella. The spawning of S. aurita presented a pick in April and for S. maderensis in July. As a shared stock these findings will be used for stock assessment in the North West Africa area.
由于其生物量增加，小沙丁鱼属最近备受关注，这可能是整个大西洋发生气候变化的结果。关于这些物种的繁殖，尤其是在摩洛哥大西洋海域，所知甚少。本研究的目的是探索摩洛哥大西洋海岸南部小沙丁鱼属的生殖生物学的一些方面。
2015年2月至2016年1月期间，在布茹杜尔角和布兰科角之间的区域每月采集样本。收集的数据包括全长、体重、性腺重量以及性别和成熟阶段。采用χ²检验比较两性之间的差异，并采用方差分析检验分析数据变化。
小沙丁鱼属是雌雄异体的鱼类。两种沙丁鱼的总体雌雄比例在统计学上没有差异（金色小沙丁鱼的χ² = 0.68，马德拉小沙丁鱼的χ² = 1.04），尽管其随季节和鱼的长度而变化。性腺指数的月度变化和性腺的宏观特征表明，摩洛哥南部的圆小沙丁鱼在2月至7月以及11月至12月产卵，4月为产卵高峰期。对于扁小沙丁鱼，它在2月至3月以及7月产卵，7月为产卵高峰期。圆小沙丁鱼雌鱼达到初次性成熟的体型比雄鱼小（分别为26.17厘米和26.78厘米）。对于扁小沙丁鱼则相反。达到性成熟的雄鱼比雌鱼小（分别为20.75厘米和21.76厘米）。
得出的结论是，初次性成熟的体型表明，摩洛哥大西洋南部海域的圆小沙丁鱼成熟雌鱼比雄鱼小，而扁小沙丁鱼则相反。金色小沙丁鱼的产卵高峰期在4月，马德拉小沙丁鱼的产卵高峰期在7月。作为共有种群，这些发现将用于西北非地区的种群评估。
