Objective:To provide a current survey of parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis(T.acus imperialis).The impact of host’s size and sex on some characteristics of the infection wa...Objective:To provide a current survey of parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis(T.acus imperialis).The impact of host’s size and sex on some characteristics of the infection was also examined.Methods:Between 2004 and 2009,126 specimens of T.acus imperialis were necropsied to study their parasites.Results:Fifteen species of metazoan parasites were collected including 3 monogeneans(Aspinatrium gallieni,Nudaciraxine imperium and Axinoides sp.),4 digeneans(Lecithostaphylus tylosuri,Tetrochetus coryphaenae,Oesophagotrema mediterranea and Sclerodistomoides pacificus),1 cestode(Ptychobothrium sp.),3 copepods(Lernanthropus tylosuri,Caligodes laciniatus and Caligus sp.),1 isopod(Irona nana),1 acanthocephalan(Rhadinorhynchus sp.),1 nematode(anisakid larvae)and 1 annelid(piscicolid).Cestoda Ptychobothrium sp.was the most frequent species(72%).Prevalence and abundance of infection with Ptychobothrium sp.and Rhadinorhynchus sp.were positively correlated with the total length of the host.Host’s sex did not seem to affect the infection parameters of parasites in T.acus imperialis.Conclusions:This study provides first information on parasitic infections in the Mediterranean needlefish T.acus imperialis off Tunisia.Parasites can be used to understand phylogeny,biology and ecology of fish host and also as bioindicators of water quality.展开更多
Objective:To present the first information on the feeding habits of the Mediterranean needlefish Tylosurus acus imperialis(T.a.imperialis)of Tunisia and to examine the diet variation in relation to the fish size,matur...Objective:To present the first information on the feeding habits of the Mediterranean needlefish Tylosurus acus imperialis(T.a.imperialis)of Tunisia and to examine the diet variation in relation to the fish size,maturity and sex.Methods:Gut contents of 92 specimens of T.a.imperialis,collected mainly from May 2004 to July 2006 off the Gulf of Gabès,Southeastern Tunisian coast,were analyzed.Results:The results showed that 55.4%of them had empty guts and 44.6%contained food in their guts.The emptiness index did not vary significantly according to size classes or sexes of T.a.imperialis.Basic food consisted of teleosts(Mugilidae,Gobidae and Belonidae)(59.63%)followed by crustaceans(40.24%),mostly decapods Sycionia carinata(5.42%).A decrease in the feeding rate at the peak of the spawning season was observed for both sexes.A diet variation among juvenile and adult specimens of T.a.imperialis was found.Conclusions:This study enhances our knowledge on the biology of the Mediterranean needlefish T.a.imperialis.This fish is an active predator and an opportunistic feeder but the feeding rate declines at the peak of the spawning season.展开更多
文摘Objective:To provide a current survey of parasitic infections in the Mediterranean needlefish Tylosurus acus imperialis(T.acus imperialis).The impact of host’s size and sex on some characteristics of the infection was also examined.Methods:Between 2004 and 2009,126 specimens of T.acus imperialis were necropsied to study their parasites.Results:Fifteen species of metazoan parasites were collected including 3 monogeneans(Aspinatrium gallieni,Nudaciraxine imperium and Axinoides sp.),4 digeneans(Lecithostaphylus tylosuri,Tetrochetus coryphaenae,Oesophagotrema mediterranea and Sclerodistomoides pacificus),1 cestode(Ptychobothrium sp.),3 copepods(Lernanthropus tylosuri,Caligodes laciniatus and Caligus sp.),1 isopod(Irona nana),1 acanthocephalan(Rhadinorhynchus sp.),1 nematode(anisakid larvae)and 1 annelid(piscicolid).Cestoda Ptychobothrium sp.was the most frequent species(72%).Prevalence and abundance of infection with Ptychobothrium sp.and Rhadinorhynchus sp.were positively correlated with the total length of the host.Host’s sex did not seem to affect the infection parameters of parasites in T.acus imperialis.Conclusions:This study provides first information on parasitic infections in the Mediterranean needlefish T.acus imperialis off Tunisia.Parasites can be used to understand phylogeny,biology and ecology of fish host and also as bioindicators of water quality.
基金Supported by the Faculty of Sciences of Sfax,Tunisia
文摘Objective:To present the first information on the feeding habits of the Mediterranean needlefish Tylosurus acus imperialis(T.a.imperialis)of Tunisia and to examine the diet variation in relation to the fish size,maturity and sex.Methods:Gut contents of 92 specimens of T.a.imperialis,collected mainly from May 2004 to July 2006 off the Gulf of Gabès,Southeastern Tunisian coast,were analyzed.Results:The results showed that 55.4%of them had empty guts and 44.6%contained food in their guts.The emptiness index did not vary significantly according to size classes or sexes of T.a.imperialis.Basic food consisted of teleosts(Mugilidae,Gobidae and Belonidae)(59.63%)followed by crustaceans(40.24%),mostly decapods Sycionia carinata(5.42%).A decrease in the feeding rate at the peak of the spawning season was observed for both sexes.A diet variation among juvenile and adult specimens of T.a.imperialis was found.Conclusions:This study enhances our knowledge on the biology of the Mediterranean needlefish T.a.imperialis.This fish is an active predator and an opportunistic feeder but the feeding rate declines at the peak of the spawning season.
