22 February 2019

Who's Got Jellies in their Gut?

Gelatinous zooplankton, loosely termed as jellyfish, can be found throughout world’s oceans, known to cause large blooms. This group includes scyphozoan jellyfish, siphonophores, ctenophores, salps, pyrosomes, and appendicularians [1]. 

If we were asked who dines on these jellies, we might reserve the term ‘belly-full-of jelly’ to charismatic sea turtles (Dermochelys coriacea, Chelonia mydas) and the ocean sunfish (Mola mola). And it's indeed fitting since an adult leatherback turtle, for instance, ingests an average of 330-kg jellyfish wet mass per day or 73% of its body mass [1]. 

With the rise of new technologies in recent years, however, this exclusivity is no longer true: It turns out that not only such massive marine predators get a chunk of their diet from jellyfish. There’s a whole lot on the table, from birds to fishes to worms, joining the feast [1].

New approaches to study the diet of marine animals such as stable isotope analyses or SIA (getting animal tissues to estimate trophic level), animal-borne cameras, remotely operated vehicles or ROVs, and DNA metabarcoding support the finding that a diverse range of marine predators feed on jellies, not incidentally but targeted [1].  

SIA revealed that jellyfish forms a substantial part of the diet of bony fishes Chloroscombrus chrysurus, Thunnus thynnus, Euthynnus alletteratus, Tetrapterus belone, Xiphias gladius and the green sea turtle Chelonia mydas

Animal-borne cameras revealed 42.2% of prey capture for some species of penguins, consuming scyphozoans, salps and ctenophores [1]. 

Metabarcoding showed that jellies make up 20% of food DNA sequences of the two species of albatross, ahead of crustaceans in terms of importance. Meanwhile, next-generation sequencing showed that the endangered European eel Anguilla anguilla has got gelatinous zooplankton in its diet. Seen through powerful ROVs, deep-sea octopus (Haliphron atlanticus) and benthic animals, like echinoderms, crabs, shrimps, amphipods, sea anemones, and worms join the slew of jellyfish predators [1].

Hays et al. 2018 Figure 2A, showing a diverse group of predators worldwide feeding on jellyfish.

Overwhelming evidence of widespread jellyfish consumption throughout the world’s oceans means that jellyfish cannot be simply considered a bycatch, but targeted and opportunistically consumed by many marine predators. However, it's important to note that this shift may be influenced by changing ocean conditions [1]. 

Also, knowing that a growing number of marine life now relies on jellyfish for nutrition signifies their susceptibility to harm, or even death, for mistaking plastic wastes for food [1]. 

These findings are important given that jellyfish holds a huge fraction of the pelagic biomass and have recently increased their abundance worldwide [3]. The study also challenges the common notion that undermines the energetic gain from jellyfish consumption, thus the need to better understand its dietary value [1].

To know more about jellyfishes and other gelatinous zooplankton, visit SeaLifeBase

[1] Hays, G. C., Doyle, T. K., & Houghton, J. D. (2018). A Paradigm Shift in the Trophic Importance of Jellyfish?. Trends in Ecology & Evolution 33(11):874-884. Retrieved from https://bit.ly/2DCvaY7
 [2] Lewis, A. (2011, January 5). Leatherback turtle feeding. YouTube. Retrieved from https://bit.ly/1vo1QO8

15 February 2019

Untangling the human-jellyfish connection

Last month's mini-symposium Q-quatics 2019: Road Ahead has been productive, providing a means for Q-quatics to communicate possibilities to execute its fisheries and oceans mandate through collaborations with the global scientific community.

Many participants took an interest in the talk of Lucas Brotz, jellyfish expert and Q-Quatics Cnidaria Scientist, as he shared the ever growing, inevitable relationship of humans and jellyfish today.

Based on a rigorous study Brotz ledjellyfish populations, indeed, have been increasing since 1950: out of the 45 large marine ecosystems (LMEs) analyzed, 62% showed increasing trends [1]. This brought with it changes that we are only now seeingmore reports of children dying from box jellyfish stings [4], swarms of jellyfish regularly interrupting fishing activities [2], jellyfish responsible for massive power failure in Luzon [3], and jellyfish turning into snacks [4]. While the demand for jellyfish for food has increased, huge economic losses are incurred by many related industries [4].

Fig. 1. Map of population trends of native and invasive species of jellyfish by large marine ecosystem (LME) (Source: Brotz et al. 2012)

A regular day for fishermen in Japan, clearing the infestations of Nomura (Copyright: Shin-ichi Uye, Hiroshima University)
Counter-measures to control jellyfish populations have been done but with mixed results. A more apparent move, to exploit jellyfish as food, was seen as an opportunity to deter this global rise. However, as Brotz pointed out, eating our way out isn't the likely solution. Rather, adaptation may be our best approach [4]. 

[1] Brotz, L., Cheung, W. W., Kleisner, K., Pakhomov, E., & Pauly, D. (2012). Increasing jellyfish populations: trends in large marine ecosystems. In Jellyfish Blooms IV (pp. 3-20). Springer, Dordrecht. Retrieved from https://bit.ly/2Ea4tvi
[2] Vince, G. (2012, April 5). Jellyfish blooms creating oceans of slime. BBC. Retrieved from https://bbc.in/2hLG1Cc
[3] BBC (1999, December 11). Jellyfish blamed for Philippines blackout. BBC News.  Retrieved from https://bbc.in/2LHCIv2

[4] Brotz, L. (2019, January 31). Jellyfish and humans - the big picture. Q-quatics 2019: road ahead symposium

12 February 2019

Q-quatics is looking for a Research Assistant

Quantitative Aquatics, Inc. is a non-stock, non-profit, non-governmental organization established in the Philippines in February 2017. Q-quatics was created to support the assembly and dissemination of key data on living aquatic resources for the development of research tools in collaboration with international partners. As such, Q-quatics manages the global biodiversity information systems FishBaseSeaLifeBase, and the global aquatic biogeography initiative, AquaMaps.

Quantitative Aquatics, Inc. seeks a Research Assistant to work in a project funded by the Minderoo Foundation Pty Ltd, in collaboration with the Sea Around Us and the University of Western Australia

08 February 2019

Q-quatics holds a mini-symposium

Q-quatics launches its year with a mini-symposium held at IRRI Training Center in Los BaƱos, Laguna last January 31. Local and international marine scientists shared emerging issues on fisheries: from (1) small-scale fisheries academy in Senegal, to (2) global assessment of exploited marine fisheries, to (3) a new analysis of global freshwater finfisheries, to (4) ballast water management, to (5) jellyfish-human relationship, to (6) the use of global databases as identification tools, and (7) the FAO global record of stocks and fisheries. If you're keen to know more about the symposium, you may read Mundus maris piece here

Participants, both local and internationalUPLB, UP Diliman, BFAR-NFRDI, NAST, National Museum, Haribon Foundation, RARE, ASEAN Center for Biodiversity, Amanpulo Resort, Oceana Philippines, Wetlands International and IRRIcontributed to a lively and productive discussion.

Cornelia E. Nauen, Q-Quatics Board of Trustee

Speakers: Top left to right: Dr. Maria Lourdes Palomares, Dr. Peter Sorensen, Dr. Benjamin Vallejo Jr.;
Bottom left to right:  Dr. Lucas Brotz, Mr. Rodolfo Reyes Jr. and Dr. Nicolas Bailly

This event became an avenue to conceive possible projects, form partnerships and strengthen existing ones with different organizations. These possibilities include the next steps inherent to the declaration of ASEAN being a "safe risk area" for international shipping, call for increased awareness in the importance of freshwater fisheries, conducting jellyfish population studies in the Philippines, and developing machine learning tools for fish identification.