EAPSI: Impacts of Human Activity on Squid Population in the Coral Reefs

Lewandowski Naomi J, Brooklyn NY

Investigators

Abstract

The researcher will study the effects of human populations on the health of coral reefs and also on the reproductive behaviors of the oval squid, a common fisheries species. Squid are an ideal behavioral study organism due to their complex mating displays and behaviors. Populations of squid are directly affected by changes in the environmental factors that support reproduction, including coral bleaching and river runoff. The study will be conducted with Dr. Yuzuru Ikeda at the University of the Ryukyus and will benefit from his expertise in laboratory and field-based cephalopod behavior research. Nearby reefs and sophisticated university facilities will allow completion of two complementary projects. Project 1: field surveys of oval squid population sizes in native reef habitats adjacent to human populations of different size; Project 2: a laboratory study of ideal reproductive habitats for oval squids. Results from these projects can inform future conservation efforts by bolstering understanding of human effects on common fishery species. The field and laboratory experiments will examine the impact of urbanization on the reproductive behavior and population size of oval squid (Sepioteuthis lessoniana). Project 1: observational studies will be conducted in the reefs near urbanized Okinawa Island and the remote reefs of the Yaeyama Islands to document oval squid egg clusters, sub-adults, adults, and coral species abundances. Project 2: the researcher will perform behavioral studies of squids in artificial reef environments. Groups of 8-10 adult oval squid will experience four habitat conditions ranging between "poor" (empty) and "enriched" (artificial seaweed and corals). Each will be observed daily for mating and spawning behaviors, including courtship signaling, spermatophore transfer, number of eggs, and egg condition. Squid communities are expected to be smaller in urbanized areas, while squid in "poor" tank conditions will show a smaller number of mating behaviors and egg clusters. This project will elucidate the effects of human activity on squid reproduction and inform conservation measures that could be applicable to many reef ecosystems. This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.