Beyond the jellyfish joyride and global oscillations: advancing jellyfish research

Journal of Plankton Research plankt.oxfordjournals.org J. Plankton Res. (2013) 35(5): 929– 938. First published online June 28, 2013 doi:10.1093/plankt/fbt063 HORIZONS Beyond the jellyfish joyride and global oscillations: advancing jellyfish research MARK J. GIBBONS1* AND ANTHONY J. RICHARDSON2,3 1 2 BIODIVERSITY AND CONSERVATION BIOLOGY DEPARTMENT, UNIVERSITY OF THE WESTERN CAPE, PRIVATE BAG X17, BELLVILLE 7535, RSA, CLIMATE ADAPTATION 3 FLAGSHIP, CSIRO MARINE AND ATMOSPHERIC RESEARCH, ECOSCIENCES PRECINCT, GPO BOX 2583, BRISBANE, QUEENSLAND 4102, AUSTRALIA AND CENTRE FOR APPLICATIONS IN NATURAL RESOURCE MATHEMATICS (CARM), SCHOOL OF MATHEMATICS AND PHYSICS, THE UNIVERSITY OF QUEENSLAND, ST LUCIA, QUEENSLAND 4072, AUSTRALIA *CORRESPONDING AUTHOR: Received April 19, 2013; accepted May 31, 2013 Corresponding editor: Roger Harris There has been debate in the literature recently about increases in jellyfish populations in response to anthropogenic change, and this has attracted widespread media interest. Despite an international collaborative initiative [National Center for Ecological Analysis and Synthesis (NCEAS) working group on jellyfish blooms] to investigate trends in global jellyfish numbers, interpretations from the data remain ambiguous. Although this is perhaps to be expected given the diversity of potential drivers, the debate has not been helped by a general lack of rigorous data and loose definitions. There is a need for the community to refocus its attention on understanding the implications of jellyfish blooms and managing them, because regardless of global trends, jellyfish are a problem in some coastal marine ecosystems. Here, we provide recommendations for advancing jellyfish research. These include directing research toward better managing jellyfish impacts, expanding research into socioeconomic consequences to grow the money available for research, building more operational and ecosystem models for tactical and strategic management, filling in the gaps in our biological knowledge for supporting models, improving surveillance using observing systems and making jellyfish research more rigorous. Some vehicles available online at www.plankt.oxfordjournals.org # The Author 2013. Published by Oxford University Press. All rights reserved. For permissions, please email: JOURNAL OF PLANKTON RESEARCH j VOLUME 35 j NUMBER 5 j PAGES 929 – 938 j 2013 to address these recommendations include international standardization of methods, a discipline-specific journal for jellyfish research and an international science program on the global ecology and oceanography of jellyfish. KEYWORDS: jellyfish; bloom; impacts; management; debate I N T RO D U C T I O N J E L LY F I S H A S H E A D L I N E S Copepods play an undeniably important role in the trophic functioning, biogeochemistry and (indirectly) socio-economics of most marine ecosystems, and consequently the number of publications on each has risen year-on-year (Fig. 1). Yet the increase in the number of publications concerning copepods fails to match those for studies on jellyfish, especially in recent times (Fig. 1). And this is a group of animals that is common only in some coastal systems, for some of the time, and which is eaten by few things of any “value” to us. If publications on jellyfish in the peer-reviewed press are on the exponential increase, the rate of change in jellyfish headlines in the popular and news press has been meteoric (Figure 3 from Condon et al., 2012). Surprising as it is, few people have ever heard of copepods (Fig. 2b), let alone understand the role they and other crustacean zooplankton play in providing us with the fish on our dinner plates. In contrast, everyone has heard of jellyfish (Supplementary data, Fig. S1): we can see them with the naked eye, they are in our folklore and our interactions with them have, for the most part, been direct and negative, particularly in western nations. When they are abundant, jellyfish can cause a multitude of problems for fishing and aquaculture: they clog and damage fishing nets; they can spoil catches and alter fishing efficiencies; they are an important occupational safety issue in some fisheries; they can kill cultured fish; they can interfere with the accurate hydro-acoustic assessment of stock sizes; and they can even capsize small vessels during fishing operations. Jellyfish can also obstruct the screens in cooling intakes of, and so temporarily cripple, both large vessels at sea as well as coastal plants for (frequently nuclear) power generation and desalination. We probably encounter jellyfish most when they spoil our enjoyment of a day at the beach. And there is no doubt that as the human population continues to rise, and as our use of the maritime environment increases, so the potential for interaction with jellyfish will increase irrespective of any changes in their Fig. 1. Numbers of papers published on copepods and jellyfish over the period 1970– 2010. The ratio between the two is also shown (spline smoothing: dotted) and it indicates that in the 1970s there were 15 times as many papers on copepods than jellyfish, now there is only approximately four times more. Data extracted on 21 May 2013 from Web of Science using the Topic search (searching Title, Abstract and Keywords) and the words “copepod* or calanoid* or harpacticoid* or cyclopoid* or poecilostomatoid*” (N ¼ 17 507) and “scyphomedusa* or hydromedusa* or ctenophor* or siphonophor* or cubomedusa*” (N ¼ 4 569). Fig. 2. Changes in the usage of the words jellyfish ( jellyfish þ Jellyfish þ jellyfishes þ Jellyfishes) and copepod (copepod þ Copepod þ copepods þ Copepods) in more than 20 million English language books from 1800– 2010 (see http://books.google.com/ ngrams; Michel et al., 2010). (a) All fiction and non-fiction, (b) fiction books only. Data extracted on 27 February 2013. 930 M.J. GIBBONS AND A.J. RICHARDSON abundance. All of these are worthy headlines, of course, but much of the media hype of late has arisen out of “science” and not spectacle, and is linked to a perception that numbers of some species of jellyfish have increased (Schrope, 2012). This potential increase has been variously attributed to human-mediated environmental change in the Anthropocene: fishing, ocean warming, hypoxia, habitat modification and coastal development, eutrophication and accompanied in some instances by alien introductions (Purcell et al., 2007; Richardson et al., 2009; Purcell, 2012). And it reflects the fact that jellyfish (medusae and polyps) certainly have the potential to respond to these anthropogenic drivers individually (and they could act synergistically) in a way that would lead to increases in population size. j JELLYFISH DEBATE By jellyfish here we refer to those zooplankton in the phyla Cnidaria and Ctenophora, and we deliberately exclude the Thaliacea that are frequently lumped with them as gelatinous zooplankton. The superficial resemblance of th (...truncated)