In Inderasabah(southeast Sabah),tri-spine horseshoe crab Tachypleus tridentatus was observed for their locomotion activity using data loggers from September to November in 2015.A female with acceleration and depth-temperature loggers and five males with acceleration loggers were recaptured between 10 and 49 days after their release.From the record of 194 activity days that involve all six T tridentatus,four horseshoe crabs,including the female,were active throughout the 24.0 h cycle,whereas the activity of the remaining two males was consistent with the 12.4h cycle.Using the 40-day recording,three horseshoe crabs,including the female,were primarily active around the new moon and full moon,but they were dormant around the first and third quarter moon days.The female spent much time in shallow shores(depth＜0.3 m)during the new moon and full moon.This result indicated that the female attempted to spawn in a minimum of three spring tide periods while lingering in the vicinity.Meanwhile,after spawning,the female spent time foraging in shallow water(depth 0.3-18m).As for the two male individuals,their activity was consistent with semi-lunar periodicity.Therefore,both of them were in amplexus.In addition,a solitary male individual was active only during the first and third quarter moon days.Through activity recording,all the T tridentatus in Inderasabah was active during daytime and night-time.This result was contrary to T tridentatus activity cycles in western Japan,where the species was found to be primarily nocturnal.Perhaps,the regional differences in activity cycles for T tridentatus were related to their population adaptation toward water temperature,depth,and prey-searching periods.

WATANABE Shinichi;NELSON Bryan Raveen;MANCA Azwarfarid;MOHAMAD Faridah

Little Leonardo Co.,Tokyo 1130021,Japan;Institute of Tropical Biodiversity and Sustainable Development,Universiti Malaysia Terengganu,Kuala Nerus 21030,Malaysia;Pertubuhan Pelindung Alam Malaysia,Casa Green Cheras 43200,Malaysia;Horseshoe Crab Research Group,Faculty of Science and Marine Environment,Universiti Malaysia Terengganu,Kuala Nerus 21030,Malaysia

中国海洋大学学报（自然科学英文版）

[1]WATANABE Shinichi;NELSON Bryan Raveen;MANCA Azwarfarid;MOHAMAD Faridah-.Activity Recording of Free-Ranging Tri-spine Horseshoe Crabs in the Southeastern Coast of Sabah,Borneo)[J].中国海洋大学学报（自然科学英文版）,2022(03):549-556

Horseshoe,Crabs,Sabah,Inderasabah,recaptured,shores,amplexus

Activity,Recording,Free,Ranging,Tri,spine,Southeastern,Coast,Borneo,southeast,horseshoe,Tachypleus,tridentatus,was,observed,their,locomotion,activity,using,data,loggers,from,September,November,female,acceleration,depth,temperature,five,males,were,between,days,after,release,From,that,involve,six,four,crabs,including,active,throughout,whereas,remaining,two,consistent,4h,Using,recording,three,primarily,around,new,moon,full,but,they,dormant,first,third,quarter,spent,much,shallow,during,This,result,indicated,attempted,minimum,spring,tide,periods,lingering,vicinity,Meanwhile,spawning,foraging,water,18m,individuals,semi,lunar,periodicity,Therefore,both,them,addition,solitary,only,Through,daytime,night,contrary,cycles,western,Japan,species,found,nocturnal,Perhaps,regional,differences,related,population,adaptation,toward,prey,searching

0.462331