The role of fins in the competitionbetween squid and fish

摘要

In recent decades cephalopod locomotion studies have focused on jet propulsion,largely ignoring the lateral fins used by almost all squid during swimming. There aremany types of fins, such as large rhomboidal fins, smaller triangular fins and longmarginal fins. Not only does fin shape vary between squid species, but also fin usagevaries, often with the lifestyle of the squid. The shape of the fins also changes duringontogenetic growth, and nearly all hatchling squid have fins proportionally smaller thanthose of adults. This change in relative size may also reflect a change in the use of the finssimilar to the different usages of the variously shaped adult fins. Understanding thesignificance of fin design will improve our ability to predict the lifestyles of rarely seensquids. Since fins are used in synchrony with the jet, there is the potential for bothsynergistic and antagonistic modes of use. Knowledge of the relative importance of finthrust in squid swimming is also essential for interpreting the new data on jet pressuresavailable from field tracking studies.