An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larach...An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larache in the north Atlantic Moroccan＇s coasts. Three species of nematodes were morphologically identified： Anisakis simplex s.l., Hysterothylacium sp., Pseudotarranova sp. According to the season, the nematode most observed in T. trachurus was .4. simplex s.1. （the highest values of prevalence （100%）, the mean intensity （48.6）. Hysterothylacium sp. was the most frequent anisakid in P. acarne with 100% of prevalence and 34.46 of the mean intensity. The infestation parameters were also analyzed according to the host species length, noting a maximum of infected fish by Anisakis simplex s.1. （96%） in samples of horse mackerel larger than 28 cm, while in axiliary seabream, the highest prevalence of infestation by Hysterothylacium sp. （100%） was found in fish more than 29 cm.展开更多
In the present paper, a study of the productivity of oocytes in 402 female individuals of the horse mackerel, Trachurus trachurus for an interval of fork length （LF） between 14 cm and 20 cm, in stage IV （pre-spawn...In the present paper, a study of the productivity of oocytes in 402 female individuals of the horse mackerel, Trachurus trachurus for an interval of fork length （LF） between 14 cm and 20 cm, in stage IV （pre-spawning） and V （spawning） was performed to estimate the fecundity rate in Oran Bay （Algerian western coast） since October 2008 to April 2009. Total fecundity （absolute and relative） were calculated using fish length, weight and eviscerated weight of gonads. Absolute fecundity by size class oscillates from 33,375 to 56,391 eggs with an average of 48,686 ±11,470. The relative fecundity ranges from 34,802 to 139,636 eggs per 100 g body weight with an average of 96,955 ± 33,814 and it is varying between 15,544 and 46,561 per gram of gonad with an average of 28,595 ±20,251. The distribution of oocytes shows that stages I and II are presented throughout the spawning season and they constitute a stockpile for subsequent clutches.展开更多
根据2001—2007年我国渔船在东南太平洋海域的智利竹筴鱼生产统计数据、时空因子以及海表温度、叶绿素浓度、海表温度梯度等环境数据,利用广义可加模型(GAM)分析了智利竹筴鱼资源变动情况及其与时空和环境因子的关系.结果表明:GAM模型...根据2001—2007年我国渔船在东南太平洋海域的智利竹筴鱼生产统计数据、时空因子以及海表温度、叶绿素浓度、海表温度梯度等环境数据,利用广义可加模型(GAM)分析了智利竹筴鱼资源变动情况及其与时空和环境因子的关系.结果表明:GAM模型对单位捕捞努力量渔获量(catch per unit effort,CPUE)总偏差解释率为31.47%;竹筴鱼生产具有明显的季节变化,主要集中在第17～41周,其中第25～31周的CPUE较高;东南太平洋智利竹筴鱼作业渔场集中在78°—98°W,30°—43.5°S之间,适宜海表温度为12℃～18℃,14℃～16℃最适宜,适宜叶绿素浓度在0.09～0.18mg·m-3,海表温度梯度在0.3℃～1.9℃.逐步建模法结果表明,影响竹筴鱼资源丰度的因子按重要性从大到小依次为周次、年份、海表温度、经度、纬度、叶绿素浓度和海表温度梯度.展开更多
文摘An epidemiological survey of anisakid nematodes was conducted on 205 specimens of horse mackerel （Trachurus trachurus） and 183 of axillary seabream （Pagellus acarne） captured in the zone between Tangier and Larache in the north Atlantic Moroccan＇s coasts. Three species of nematodes were morphologically identified： Anisakis simplex s.l., Hysterothylacium sp., Pseudotarranova sp. According to the season, the nematode most observed in T. trachurus was .4. simplex s.1. （the highest values of prevalence （100%）, the mean intensity （48.6）. Hysterothylacium sp. was the most frequent anisakid in P. acarne with 100% of prevalence and 34.46 of the mean intensity. The infestation parameters were also analyzed according to the host species length, noting a maximum of infected fish by Anisakis simplex s.1. （96%） in samples of horse mackerel larger than 28 cm, while in axiliary seabream, the highest prevalence of infestation by Hysterothylacium sp. （100%） was found in fish more than 29 cm.
文摘In the present paper, a study of the productivity of oocytes in 402 female individuals of the horse mackerel, Trachurus trachurus for an interval of fork length （LF） between 14 cm and 20 cm, in stage IV （pre-spawning） and V （spawning） was performed to estimate the fecundity rate in Oran Bay （Algerian western coast） since October 2008 to April 2009. Total fecundity （absolute and relative） were calculated using fish length, weight and eviscerated weight of gonads. Absolute fecundity by size class oscillates from 33,375 to 56,391 eggs with an average of 48,686 ±11,470. The relative fecundity ranges from 34,802 to 139,636 eggs per 100 g body weight with an average of 96,955 ± 33,814 and it is varying between 15,544 and 46,561 per gram of gonad with an average of 28,595 ±20,251. The distribution of oocytes shows that stages I and II are presented throughout the spawning season and they constitute a stockpile for subsequent clutches.
文摘根据2001—2007年我国渔船在东南太平洋海域的智利竹筴鱼生产统计数据、时空因子以及海表温度、叶绿素浓度、海表温度梯度等环境数据,利用广义可加模型(GAM)分析了智利竹筴鱼资源变动情况及其与时空和环境因子的关系.结果表明:GAM模型对单位捕捞努力量渔获量(catch per unit effort,CPUE)总偏差解释率为31.47%;竹筴鱼生产具有明显的季节变化,主要集中在第17～41周,其中第25～31周的CPUE较高;东南太平洋智利竹筴鱼作业渔场集中在78°—98°W,30°—43.5°S之间,适宜海表温度为12℃～18℃,14℃～16℃最适宜,适宜叶绿素浓度在0.09～0.18mg·m-3,海表温度梯度在0.3℃～1.9℃.逐步建模法结果表明,影响竹筴鱼资源丰度的因子按重要性从大到小依次为周次、年份、海表温度、经度、纬度、叶绿素浓度和海表温度梯度.
