Population Structure And Spatial Heterogeneity Of Jumbo Flying Squid Dosidicus Gigas In The Southeast Pacific Ocean

Dosidicus gigas are the oceanic shallow water species and the largest cephalopod individuals, they are one of the most abundant species. Dosidicus gigas are widely distributed in the Pacific area and their population structure is complex, there are significant differences in individual form. At present, there doesn't exist a unified conclusion for squid biology, population structure. To study the squid population structure and its change mechanism, we collected the debases of Chile, Costa Rica, waters off the coast of Peru. We discussed on its morphology, horny jaws and otolith morphology data, using multivariate statistics, spatial heterogeneity of squid theory of population structure and spatial heterogeneity were analyzed.1. Mantle length is the most significant factor of charactering changes of the external form. The External morphology of squid organizations grows at different speed, and the growth pattern is different in different sea areas. Keratinocytes in the upper jaw length is the most significant factor of charactering morphology of squid.The parts of keratinocytes also grow at different speed. There are no significant differences in left of right otolith, dorsal region, lateral zone, kiss zone change have an important role in morphological change of squid. The parts of the otolith grows at different speed. The trend for the overall otolith shape is narrow, narrow head of a kiss, large dorsal region, the focus of continued support or oppose transfer to otolith zone.2. When TSL is 1600μm,this is the dividing poin of otolith length, there are significant difference in the progress of growth. The changes of form is located with the changes of the movements of the water layer .3. There are several spawning groups off the coast of Chile, however, the spawning time is concentrated. There are two spawning groups of spring and autumn.4. From the data of external morphology, horny jaws, otolith morphology, we achieved the good identification of the groups of the sea. The correct rate of determing is over 60%. However, differences between groups belonging to different species, which did not reach the level of subspecies.5. During the development of growth,morphological characters appear more differences in large individuals than small individuals, which is caused by the environmental change,.Then .leading a significant difference of the morphological characteristics of large groups in different sea areas. For large individuals, according to individual differences in prey species, horny jaw squid appears to have developed different adaptive growth was significant differencein the different sea. Large significant differences exist in tolith morphological characteristics, it is because that the individual squid should adapt to the environment and habitat, which exsiting adaptive changes in movement pattern, the there are significant difference in large-scale morphological characteristics.6. There are different discriminant results with different groups of sea evaluation .For the groups of Chile, Costa Rica, the morphological characteristics are the best results to determine. For the groups off the coast of Peru, the tolith characteristics are the best results to determine. There are not good results by composite indicators, which related with different growth stages in significant growth.7. The result off the coast of Costa Rica is the best, then is the group off the coast of Chile, Peru, the worst discrimination groups. This difference may be related to distribution and spawning grounds of the migratory squid way.8. Population spatial distribution is correlated, but groups in different months on the distribution pattern in different directions are different. According to changing patterns of spatial distribution of population, we can see changes in population and reproductive space due to population distribution-related migration. Squid often spawns on the continental shelf of north shore in Peru. As the waters in the eastern boundaryis upwelling systems, eggs in Peru and offshore ocean currents flow to the southeast and northeast under the drifting in both directions, the one to the southeast flow into the sea in Chile, and the one to the northeast flows into the southern equatorial current system, then in the equatorial countercurrent, the role of the equatorial undercurrent, the eggs re-entry back into the east coast of the Costa Rica Dome by the surface water and the eggs hatch in the area, after hatching, some larvae migrate to the south again along the coast of Peru, or intellectual of Chile.9. By contrast analysis of morphology, horny jaws, and three parameters otolith comprehensive index of spatial heterogeneity, the four parameters obtained similar results. But in May 2008 off the coast of Chile, September, November large groups, off the coast of Costa Rica, the size of groups, although the analysis of different parameters did not achieve the opposite result, but there are some in the direction of bias. One reason may be the investigation of limited scope, there is a certain impact on the results. On the other hand may be off the coast of Chile, Costa Rica, there are several area groups, relative to the external morphology of hard tissues more vulnerable to external environment, so in the analysis there are some deviations. We know the score differences on the dimension, the external morphology of the fractal dimension of the corresponding parameters of less volatile, no significant difference in different groups, and the horny jaws, otolith parameters obtained for the existence of fractal dimension of greater volatility, a significant difference between different groups . The results also proved that there are multiple groups in the area, and the hard tissue structure is relatively stable characteristics.