| Winter-spring cohort of neon flying squid Ommastrephes bartramii in the Northwest Pacific Ocean has great economic value,is the main fishing fishing community in our country,its early life history stage without swimming ability,only with the current passive transport,unable to cope with the complex environment of change,even a minor change in the surrounding environment has great influence on the biological process,but the predecessors in the study,mainly using collected samples were analyzed,and the samples were collected in the majority with mature neon flying squid Ommastrephes bartramii,didn’t specializes in his early life history stage,less studies from the perspective of the individual.The research on this stage can contribute to the rational development,resource protection and sustainable utilization of neon flying squid Ommastrephes bartramii.Therefore,in order to early life history of winter-spring cohort of neon flying squid Ommastrephes bartramii in the Northwest Pacific Ocean of biological process is studied,its growth,death early biological process parameters,used the physical model(FVCOMGlobal)to simulate and generate three-dimensional physical field of the North Pacific(10°N～60°N,120°E～110°W),and adopted the Lagrangian particle tracking method to couple the physical model and the biological model(individual-based model),and constructed an individual-based ecological dynamics model of early life history stage of winter-spring cohort of neon flying squid Ommastrephes bartramii in the Northwest Pacific Ocean,and used this model to numerically simulate the transport distribution and recruitment of winter-spring cohort from 1997 to 2010.The simulation results showed:(1)At 23℃ as the optimal water temperature,the closer to the optimal water temperature in a certain temperature range,the faster the growth rate of winter-spring cohort would be.When the age of the day was 38 days,the maximum mantle length could reach 11.76 mm.When the optimal temperature was higher or lower than the optimal temperature,mantle length would decrease,but the overall trend remained unchanged.When the daily age was about 40 days,the growth curve of mantle length changed from exponential growth to linear growth.The simulation results under the one-dimensional condition of are basically similar to the growth curve of the previous study.It shows that the parameterization in the biological model is reliable.(2)In the model,the initial spawning time is set as February 1 of each year,and the spawning peak is reached in the middle of February.The remaining neon flying squid Ommastrephes bartramii at the end of the simulation is the supplement of neon flying squid Ommastrephes bartramii resources in the study area,which is called the simulative recruitment.The annual fluctuation of the simulative recruitment indicated that the environmental changes would have an impact on the recruitment.The variation trend is not consistent with the previous statistics of the catch,because the model is set to have the same number of neon flying squid Ommastrephes bartramii parent in each year.Taking into account the difference in the number of winter-spring cohort parent,the years with the highest and lowest actual recruitment were 1999 and 2009,which were similar to the trend of catch and closer to the actual situation.(3)In the horizontal direction,the winter-spring cohort were mainly located in the spawning field during the simulation stage.Due to 25°N south of the flow of current is mainly in western and northwestern,make originally the spawning ground in the southwest and southeast of neon flying squid Ommastrephes bartramii transport to the west and northwest,but current in 25°～28°N gradually showed a trend of north and northeast of transport and weaker than 25°N south of some intensity,make the neon flying squid Ommastrephes bartramii transport distance far west and spawning ground in the northwest and southwest of relatively large neon flying squid Ommastrephes bartramii;in the north of 28°N more especially greatly influenced by the Kuroshio Current strength,and have turned to the trend of northeast,so part neon flying squid Ommastrephes bartramii of the transport to the west and northwest when affected by the Kuroshio will eventually to the north or northeast transport at a faster pace,and is located in the northeast of the neon flying squid Ommastrephes bartramii is located in the southeast of the neon flying squid Ommastrephes bartramii is big.(4)In the vertical direction,larvae have been collected in water depths of 100 m,in order to verify the parameters set in this paper can make the larvae appeared in the 100 m water depth,the proportion of the first batch of eggs that grew into larvae in different depths was calculated,the results showed that the larvae accounted for the largest proportion in water depth of 100 m,average close to half of the total,and that at this stage,it mainly distributed in the shallow layer;the proportion of winter-spring cohort distributed in different water depths at four stages of the early life history was statistically analyzed,found the four stages distribution within 100 m depth ratio is the highest,at least in the more than 40%,the overall distribution will be transported with the passage of time deeper layer;according to the statistics of the proportion of winter-spring cohort distributed in different water depths during the whole simulation stage,it was found that there were a few neon flying squid Ommastrephes bartramii above 1500 m,but the environment was not suitable for their growth,so they basically could not survive and would die within a certain period of time.(5)Set the spawning depth to a shallower location,namely from 100 m to 75 m,in the same year,the growth of the neon flying squid Ommastrephes bartramii in different depths was very similar in the first 15 days,after 15 days,the difference in mantle length became larger and the mantle length of the neon flying squid Ommastrephes bartramii started at 75 m was longer than that of the neon flying squid Ommastrephes bartramii started at 100 m,it means within a certain range,when the spawning water depth became shallower,the growth rate of neon flying squid Ommastrephes bartramii accelerated,but the overall trend of growth curve was basically the same.It may be related to the increase of mantle length growth rate due to the increase of water temperature as the water depth became shallower.(6)When change the location of the spawning ground,all sorts of data in the model change.The spawning ground was moved westward and eastward respectively,from the original 20°～30°N,140°～150°E to 20°～30°N,130°～140°E and 20°～30°N,150°～160°E.Among the three spawning grounds,the most rapid growth of the spawning ground was produced by moving the spawning ground to the east,followed by the spawning ground to the west,the slowest growth of the spawning ground before the spawning ground changes.Due to move the spawning ground to the east after the super individual than the other two spawning grounds of super individual a lot more,as a result,the number of eggs produced also many,finally get the simulative recruitment is most likely associated with the three spawning grounds,however,the number of simulative recruitment at the three spawning grounds was consistent with the growth order of the three mantle length,however,mantle length was positively correlated with water temperature,so simulative recruitment might also be positively correlated with water temperature.On the horizontal direction,move the spawning ground to the west,from transport to all round the distance of the farthest neon flying squid Ommastrephes bartramii relative to the spawning ground,the proportion of the neon flying squid Ommastrephes bartramii in different waters,and distribution of these angle as you can see,a few similar to the distribution of spawning ground before mobile neon flying squid Ommastrephes bartramii,the difference is due to the spawning ground to move west closer to the Kuroshio compared with the original,so to the north and northeast of transport than the original more obvious;move the spawning ground to the east,from different perspective,the transport in the east-west direction was consistent with that before the movement,but the transport in the northsouth direction changed from the original northward transport to the southward transport,which indicated that the more eastward the spawning ground was the less affected it was by the Kuroshio Current,and the more affected it was by the Kuroshio Countercurrent.In the vertical direction,by comparing the west-moving spawning ground with the eastmoving spawning ground,it was found that the proportion of neon flying squid Ommastrephes bartramii in shallow and deep layers decreased,indicating that the sea area most strongly affected by the Kuroshio Current would quickly transport neon flying squid Ommastrephes bartramii to each water layers. |
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