Lucas Brotz – Ph.D. Student



BSc (Astrophysics); MSc (Oceanography); currently enrolled in PhD (Zoology)

Research Interests

Jellyfish populations are increasing in numerous ecosystems around the globe. Not surprisingly, these increases are not uniform across time and space. So why are jellyfish increasing in some places and not others? What are the consequences for humans and ecosystems? And what, if anything, can we do to manage or prevent increasing jellyfish blooms?

Jellyfish population dynamics are complex, partly because of the unique life cycles of many species. Jellyfish may exist as pulsing medusae, sessile polyps, or cysts capable of resisting harsh environmental conditions. Reproductive strategies include sexual and asexual reproduction, as well as hermaphroditism. As such, jellyfish populations are influenced by a variety of anthropogenic and environmental factors at different, often cryptic, life stages.

Increasing jellyfish populations can impact humans in both negative and positive ways. Industries such as tourism, aquaculture, fishing, power generation, desalination, and shipping have all reported considerable economic losses due to jellyfish blooms. In contrast, fisheries that harvest jellyfish for food are expanding around the globe, and jellyfish are now a popular draw for public aquaria. As both human and jellyfish populations increase, new interactions are sure to emerge, as jellyfish get in our way and as we find new ways to exploit them.

Ironically, it appears that in some cases, humans may be responsible for the observed increases in jellyfish populations. While there is no single cause of increasing jellyfish populations, there is evidence that fishing, pollution, aquaculture, shipping, global warming, and coastal development can all create conditions that favour jellyfish over fish. Most of these links are only correlative, but the rise of jellyfish in coastal ecosystems worldwide should be cause for concern. We may need to decide now whether or not we want our children to be eating jellyfish burgers. If our behaviour doesn’t change, they might not have a choice.


Gregr, E.J., R. Gryba, M.C. James, L. Brotz, & S.J. Thornton (in revision). Information relevant to the identification of critical habitat for Leatherback Sea Turtles (Dermochelys coriacea) in Pacific Canadian waters. DFO Canadian Science Advisory Secretariat Research Document.

Brotz, L. & D. Pauly (in press). Jellyfish populations in the Mediterranean Sea. Acta Adriatica.

Duarte, C.M., K.A. Pitt, C.H. Lucas, J.E. Purcell, S. Uye, K. Robinson, L. Brotz, M.B. Decker, K.R. Sutherland, A. Malej, L. Madin, H. Mianzan, J.M. Gili, V. Fuentes, D. Atienza, F. Pagés, D. Breitburg, J. Malek, W.M. Graham, & R. Condon (in press). Is global ocean sprawl a cause of jellyfish blooms? Frontiers in Ecology and the Environment.

Brotz, L. (2012) Of leatherbacks and lion’s manes. Sea Around Us Project Newsletter (71): 1-4.

Brotz, L., W.W.L. Cheung, K. Kleisner, E. Pakhomov, & D. Pauly (2012). Increasing jellyfish populations: trends in Large Marine Ecosystems. Hydrobiologia 690(1): 3-20 (Open Access).

Brotz, L. (2012). Learning about Pacific leatherback sea turtles by examining jellyfish. Report prepared for Fisheries and Oceans Canada, 29 pp.

Brotz, L. (2011). Increasing jellyfish populations: trends in Large Marine Ecosystems. Fisheries Centre Research Report 19(5): 105 pp (Open Access).

Brotz, L., M. Lebrato, K.L. Robinson, M. Sexton, A. Sweetman, K. Pitt, & R. Condon (2011) Implications of increased carbon supply for the global expansion of jellyfish blooms.Limnology & Oceanography Bulletin (20): 38-39.

Brotz, L. (2011) Are jellyfish the food of the future? INFOFISH International (4): 60-63.

Brotz, L. (2010) Gelatinous Seas. Discovery, Nature Vancouver (39): 14-20.

Brotz, L. (2010) Mi Querida Argentina (My Beloved Argentina). Sea Around Us Project Newsletter (60): 1-3.

Brotz, L. (2010) What’s for dinner? Sea Around Us Project Newsletter (57): 4-5.

Media Coverage

Jellyfish Invasion, Costing the Earth, BBC Radio, May 22, 2012.

Rise of the jellies, Quirks & Quarks, CBC Radio, April 28, 2012.

Jellyfish numbers soar worldwide. CTV News Channel, April 21, 2012.

Jellyfish populations booming, CBC News, April 20, 2012.

Menace from the ocean deep. National Post, April 19 2012 (front page).

Jellyfish swarm coastal waters. Vancouver Sun, April 19, 2012 (front page).

Interview, As It Happens, CBC Radio, April 19, 2012.

Attack of the blobs. Nature (482): 20-21, February 2, 2012.

Growing jellyfish invasion oozes across southern U.S. The Toronto Star, September 20, 2011.

Jellyfish Swarms: Menacing or Misunderstood? LiveScience, October 20, 2010.

Interview – Fisheries Broadcast, CBC Radio Newfoundland, August 20, 2010.

Tofu of the Sea. Edible Vancouver (12): 18-19, Summer 2010.

Invasion of the Holiday Snatchers. The, March 28, 2008.

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