Ecology

Throughout its life, Humboldt squid is an important prey item for many fishes, mammals and birds in open ocean ecosystems and supports the largest invertebrate fishery in the world [1-3]. The distribution and mean size of Humboldt squid is highly variable; they appear to respond quickly to changes in the environment by altering their distribution or maturing precociously when conditions become unfavorable [4,5]. To gain a better understanding of how this plasticity in life history and distribution might affect ecosystems and economies that Humboldt squid support, we examine how Humboldt squid interact with their habitat and are working to determine what conditions can be considered “favorable” for Humboldt squid.

We have two ongoing projects that are attempting to address these questions. The first utilizes pop-up archival tags, attached to the fins of large squid, to examine the depth and temperature of the habitat utilized by Humboldt squid throughout the day. These data have provided a first glimpse of the vertical and horizontal the movements of large squid and help us to build a baseline from which changes in these behaviors could be observed during episodic reductions in squid size. To overcome the limitation of our tags to large squids, we also use bioacoustics, diet, hydrographic and remotely sensed data to more broadly characterize squid habitat based on temperature and food availability.

• 1. FAO (2014). FAO Yearbook. 2012. Rome. 77 pp
• 2. Nigmatullin, C. M., Nesis, K., & Arkhipkin, A. (2001). Fisheries Research, 54: 9–19.
• 3. Markaida, U., Gilly, W. F., Salinas-Zavala, C. A., et al. (2008). CalCofi Report, 49:90–103.
• 4. Hoving, H.-J. T., Gilly, W. F., Markaida, U., et al. (2013). Global Change Biology, 19(7):2089–103.
• 5. Stewart, J. S., Hazen, E. L., Bograd, S. J., et al. (2014). Global Change Biology, 20(6):1832-43.