Abstract
In the face of increasing anthropogenic pressures acting on the Earth system, urgent actions are needed to guarantee efficient resource management and sustainable development for our growing human population. Our oceans—the largest underexplored component of the Earth system—are potentially home for a large number of new resources, which can directly impact upon food security and the wellbeing of humanity. However, the extraction of these resources has repercussions for biodiversity and the oceans ability to sequester green house gases and thereby climate. In the search for “new resources” to unlock the economic potential of the global oceans, recent observations have identified a large unexploited biomass of mesopelagic fish living in the deep ocean. This biomass has recently been estimated to be 10 billion metric tons, 10 times larger than previous estimates however the real biomass is still in question. If we are able to exploit this community at sustainable levels without impacting upon biodiversity and compromising the oceans' ability to sequester carbon, we can produce more food and potentially many new nutraceutical products. However, to meet the needs of present generations without compromising the needs of future generations, we need to guarantee a sustainable exploitation of these resources. To do so requires a holistic assessment of the community and an understanding of the mechanisms controlling this biomass, its role in the preservation of biodiversity and its influence on climate as well as management tools able to weigh the costs and benefits of exploitation of this community.
Introduction
One of the most understudied regions in the world oceans is the twilight zone (200–1000 m depth) which is the domain of the mesopelagic community. Lanternfishes (Myctophiids), which dominate the fish community, are a diverse group comprising around 245 species in 33 genera, distributed globally from polar to equatorial waters, with a maximum body size of 10–15 cm (Paxton, ). Along with an associated community of mainly mesopelagic crustaceans and cephalopods Figure 1 (Feagans-Bartow and Sutton, ), the community forms distinct acoustic scattering layers at around 500 m over large expanses of the ocean during day-time, ascending to the upper 150 m and dispersing at night (Figure 2). This diel migration has been referred to as the “largest daily migration of animals on earth” (Hays, ; van Haren and Compton, ). The discovery of new species from viruses to large vertebrates is regular in this oceanic zone, supporting estimates of a million undescribed species living in the deep pelagic (Robison, ).
Figure 1
Figure 2
Resource strategists have identified the mesopelagic fish and plankton community, living in this twilight zone of the ocean (200–1000 m, depth), as a potential unexploited resource potentially contributing to the long term Blue Growth strategy set by the European Union, i.e., “smart, sustainable and inclusive economic and employment andgrowthfrom the oceans, seas and coasts”, (e.g., Gjøsæter and Kawaguchi,
Despite the potential benefits, harvesting from this community (e.g., mesopelagic fish biomass recent estimates of 10 billion tons although still in question) is problematic and comes with a number of risks. For example, the community plays an integral role in carbon sequestration and thus climate regulation (e.g., Hidaka et al.,
Food provision
Food insecurity is a major global issue, with human populations across much of central Africa and southeast Asia facing significant hunger today. Presentations at the COP 21 Agreements (
What is the potential for contributing to human nutrition? Considering a human population on the order of 7.5 billion people this equates to 1.3 metric tons of mesopelagic fish biomass per human on the planet. Putting the estimate of Irigoien et al. (
There are some caveats however. From an industry perspective, the Director General of IFFO (the Fish Meal and Fish Oil producers and consumer's organization), Andrew Mallison, has stated “The industry is certainly in need of more raw material – demand exceeds supply and demand is forecasted to continue growing as global aquaculture (and feed) increases. However, these deeper water fish will be more costly to harvest, and there would have to be a good set of science based harvest control rules to satisfy any environmental or ecosystem impact concerns. If the science indicates a potential sustainable fishery with a reasonable yield, there are several IFFO member companies who could look at the economics of fishing effort and return.”
Nutraceuticals
Another key issue in human nutrition and aquaculture is the availability of nutraceuticals. The growth of nutraceutical products is partly based on a demand for “Omega-3” oils as human dietary supplements, and partly on the expanding aquaculture industry which has a requirement for n-3 LC-PUFA in feed material which can currently only be met from natural marine oils. Mesopelagic fisheries targeting nutraceutical-rich species to meet these demands are a new and emerging concept, convergent with the theme of Blue Growth. In the North Atlantic the prime example of an already operational commercial marine nutraceutical venture is “Calanus Oil,” which is extracted from the copepod Calanus finmarchicustif, harvested in the coastal waters of the Norwegian Sea (http://calanus.no/en/products/), and marketed in various forms as being rich in omega-3 fatty acids. Lanternfishes are recognized as being high in fatty acids (e.g., Lea et al.,
On the Blue Growth nutraceutical potential of mesopelagic fishes, the Director General of IFFO said “The nutraceuticals market does offer better returns for oil than animal feed—it would be interesting to know what loading of PCB's and Dioxin-like PCB's are present as some other North Atlantic fish oil sources require filtering. This incurs a greater cost than South American oils which are ‘cleaner’ but have to be shipped further to reach EU markets”.
Hence, it seems that the Blue Growth potential of Lanternfishes exploitation may be at a cusp between an existing market (for bulk fishmeal) that seems to be barely profitable using exiting harvesting and processing approaches under existing demand conditions and an early-stage emerging market (for nutraceuticals) that could be profitable in the future (Koizumi et al.,
Climate regulation
As is clearly outlined at the COP 21 meeting in Paris in 2015, “Parties should take action to conserve and enhance, as appropriate, sinks and reservoirs of greenhouse gases in order to do so an improved knowledge base for the assessment, monitoring and evaluation of the dynamics of carbon sequestration and thus climate regulation is necessary”. The mesopelagic region of the ocean, and the community that inhabits it, plays a significant role in the global carbon cycle. The concentration of atmospheric carbon dioxide would be ~50% higher without the biological carbon pump (BCP) fixing inorganic carbon through photosynthesis by phytoplankton in the surface waters and “exporting” it to depth in the ocean (Parekh et al.,
Biodiversity
The participating Nations at COP 21 Agreements (
There is, however, a major lack of knowledge of the global composition and distribution of mesopelagic diversity, which is under-sampled and sparse in data (Figure 1). An additional problem is that we know very little about the function of mesopelagic biodiversity in the oceanic ecosystems and as providers of critical ecosystem services (Robison,
This lack of knowledge impedes implementation of international agreements such as: (i) UN Resolution 61/1054 to conserve Vulnerable Marine Ecosystems; (ii) Aichi targets, related to the sustainable management of marine exploitation (applying ecosystem based approaches, avoiding adverse impacts on threatened species and vulnerable ecosystems and ensuring that the impacts of fisheries on stocks, species and ecosystems are within safe ecological limits); (iii) the Convention on Biological Diversity (2009), to identify ecologically or biologically sensitive areas; and (iv) the development of indicators required to assess the environmental status of marine ecosystems under different national and international legislation (i.e., Oceans Act, in US and Canada; Marine Strategy Framework Directive, in Europe; Regional Seas Conventions, worldwide; etc.).
Conclusions and suggestions
The potential negative impacts of anthropogenic activities and climate change on marine ecosystems and human health must be addressed in a full realization of Blue Growth strategy of the mesopelagic. Exploitation of this community is a delicate problem in terms of the consequences for the ecosystem and its services. To tackle the global challenge of securing access to strategic but vulnerable food resources while coping with climate change risks, we need targeted innovation and sustainable development strategies that aim at preserving critical ecosystem services. This includes our oceans as providers, as claimed by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES http://www.ipbes.net). Hence, there is a need to improve resource management (through an ecosystem approach) and governance, to preserve them and to unlock their potential for the sustainable production of new products and industrial applications. To achieve this in relation to the mesopelagic community and its services we need knowledge on
Population vital rates (e.g., recruitment, natural mortality and the effects of abiotic and biotic stressors on growth and survival) with respect to latitude and environmental conditions as the basis for stock assessments and population dynamics modeling to predict the sustainability of harvest rates.
Stock assessments to address fisheries policy. In the absence of a fishery, there are no existing data on which to base a conventional stock assessment, so we must use other methods relying on survey data and measurements of growth, maturity and natural mortality rates to generate assessments and forecasts of yields under different harvesting rates.
The links between oceanographic regimes and mesopelagic biomass and biodiversity (species, traits, population genetics and habitats) thus enabling the prediction of species dynamics relative to oceanographic regimes which will be impacted as their environment alters under climate change.
The role of the community in the food web, in particular the dependence of top predators on mesopelagic prey and thus their influence on fisheries and ecotourism.
The role of individual species and the community in the sequestration of green house gases.
Clearly the potential benefits of harvesting the mesopelagic community is immense, however the consequences of mismanagement, unlike for most fish stocks, have global ramifications. Prior to exploitation a scientifically based ecosystem approach to exploitation is needed in particular focusing on the ecosystem and climate controls on the populations in order to avoid an overexploited state as is observed in many marine fish stocks (e.g., Worm et al.,
Funding
All authors were funded by their affiliated agencies.
Conflict of interest statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Statements
Author contributions
All authors listed, have made substantial, direct and intellectual contribution to the work, and approved it for publication.
Acknowledgments
We would like to thank Drs. Webjørn Melle and Thor Klevjer from the Norwegian Institute for Marine Research for making the echograms and photographs presented in Figures 1, 2 available to the authors and the home institutes of the authors for providing the funding necessary to generate this article.
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
References
1
BenwayH. M.HofmannE.St. JohnM. A. (2014). Building international research partnerships in the North Atlantic-Arctic region. EOS95, 317. 10.1002/2014EO350007
2
BranchT. A.JensenO. P.RicardD.YeY.HilbornR. (2011). Contrasting global trends in marine fishery status obtained from catches and from stock assessments. Conserv. Biol.25, 777–786. 10.1111/j.1523-1739.2011.01687.x
3
BrophyJ. T.MurphyS.RoganE. (2009). The Diet and Feeding Ecology of the Short-Beaked Common Dolphin (Delphinus delphis) in the Northeast Atlantic. IWC Scientific Committee Document SC/61/SM 14. Cambridge: International Whaling Committee.
4
ConstableA. J.de la MareW. K.AgnewD. J.EversonI.MillerD. (2000). Managing fisheries to conserve the Antarctic marine ecosystem: practical implementation of the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR). ICES J. Mar. Sci.57, 778–791. 10.1006/jmsc.2000.0725
5
COP 21 Agreements (2015). POLICY: https://www.wfp.org/climate-change/climate-policy/cop-21; FOOD SECURITY: http://www.globalfood.cam.ac.uk/news/world-food-programme-at-the-paris-climate-conference; BIODIVERSITY: http://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf)
6
DavisonP. C.CheckleyD. M.Jr.KoslowJ. A.BarlowJ. (2013). Carbon export mediated by mesopelagic fishes in the northeast Pacific Ocean. Progr. Oceanogr.116, 14–30. 10.1016/j.pocean.2013.05.013
7
DavisonP. C.KoslowJ. A.KloserJ. (2015). Acoustic biomass estimation of mesopelagic fish: backscattering from individuals, populations, and communities. ICES J. Mar. Sci.72, 1413–1424. 10.1093/icesjms/fsv023
8
FAOI. (1997). Review of the State of World Fishery Resources: Marine Fisheries. Lanternfishes: a Potential Fishery in the Northern Arabian Sea?Rome: FAO. FAO Fisheries Circular No. 920 FIRM/C.920
9
FAOI. (1998). Trial Fishing for Lantern Fishes (Myctophids) in the Gulf of Oman (1998-1990). Rome: FAO. FAO Fisheries Circular No. 935 FIRM/C.935.
10
FAOI. (2001). Report of the Trilateral Workshop on Lanternfish in the Gulf of Oman, Muscat, Oman, 7-9 May 2001.Muscat: FAO. FAO Fisheries Report No. 665 FIIT/R.665.
11
FAOI. (2014) State of World Fisheries Aquaculture 2014. Rome: Food Agriculture Organization.
12
Feagans-BartowJ.SuttonT. (2014) Ecology of the oceanic rim: pelagic eels as key ecosystem components. Mar. Ecol. Prog. Ser.502, 257–266. 10.3354/meps10707
13
Galway Statement on Atlantic Ocean Co-operation (2014). Available online at; http://ec.europa.eu/research/index.cfm?pg=newsalertandyear=2015andna=na-160415-1
14
GieringS. L. C.SandersR.LampittR. S.AndersonT. R.TamburiniC.BoutrifM.et al. (2014). Reconciliation of the carbon budget in the ocean's twilight zone. Nature507, 480–483. 10.1038/nature13123
15
GjøsæterJ.KawaguchiK. (1980). A Review of the World Resources of Mesopelagic Fish. Food and Agriculture Org.
16
HaysG. (2003). A review of the adaptive significance and ecosystem consequences of zooplankton diel vertical migrations. Hydrobiologia503, 163–170. 10.1023/B:HYDR.0000008476.23617.b0
17
HeinoM.PorteiroF. M.SuttonT. TFalkenhaugT.GodøO. R.PiatkowskiU. (2011). Catchability of pelagic trawls for sampling deep-living nekton in the mid-North Atlantic. ICES J. Mar. Sci.68, 377–389. 10.1093/icesjms/fsq089
18
HidakaK.KawaguchiK.MurakamiM.TakahashiM. (2001). Downward transport of organic carbon by diel migratory micronekton in the western equatorial Pacific: its quantitative and qualitative importance. Deep Sea Res.1 Oceanogr. Res. Papers48, 1923–1939. 10.1016/S0967-0637(01)00003-6
19
HudsonJ. M.SteinbergD. K.SuttonT. T.GravesJ. E.LatourR. J. (2014). Myctophid feeding ecology and carbon transport along the northern Mid-Atlantic Ridge. Deep Sea Res. I. 93, 104–11610.1016/j.dsr.2014.07.002
20
IrigoienX.KlevjerT. A.RøstadA.:, Martinez, U.BoyraG.AcuñaJ. L.et al. (2014). Large mesopelagic fishes biomass and trophic efficiency in the open ocean. Nat. Communicat.5, 3271. 10.1038/ncomms4271
21
JónasdóttirS. H.VisserA. W.RichardsonK.HeathM. R. (2015). Seasonal copepod lipid pump promotes carbon sequestration in the deep North Atlantic. Proc. Natl. Acad. Sci. U.S.A.112, 12122–12126. 10.1073/pnas.1512110112
22
KaartvedtS.TorgersenT.KlevjerT. A.RøstadA.DevineJ. A. (2008). Behavior of individual mesopelagic fish in acoustic scattering layers of Norwegian fjords. Mar. Ecol. Progr. Ser.360, 201–209. 10.3354/meps07364
23
KaruppasamyP. K.BalachandranK.GeorgeS.BaluS.PersisV.MenonN. G. (2007). A check list of fishes collected by IKMT from the DSL survey in the Indian EEZ of Arabian Sea. J. Indian Hydro.9, 311–316.
24
KoizumiK.HuratsukaS.SaitiH. (2014). Lipid and fatty acids of three edible Myctophids, Diaphus watasei, Daipus suborbitalis, and Benthosema pterotum: high levels of icosapentaenoic and docosahexaenoic acids. J. Oleo Sci.63, 461–470. 10.5650/jos.ess13224
25
KorneliussenR. J.OnaE.EliassenI.HeggelundY.PatelR.GodøO. R.et al. (2006). The large scale survey system - LSSS, in Proceedings of the 29th Scandinavian Symposium on Physical Acoustics (Ustaoset), 29.
26
KoslowJ. A.KloserR. J.WilliamsA. (1997). Pelagic biomass and community structure over the mid-continental slope off southeastern Australia based upon acoustic and midwater trawl sampling. Mar. Ecol. Progr. Ser. 146, 21–35. 10.3354/meps146021
27
KwonE. W.PrimeauF.SarmientoJ. L. (2009). The impact of remineralization depth on the air–sea carbon balance. Nat. Géosci. 2, 630–635. 10.1038/ngeo612
28
LeaM. A.NicholsP. D.WilsonG. (2002). Fatty acid composition of lipid-rich myctophids and mackerel icefish (Champsocephalus gunnari) – Southern Ocean food-web implications.Polar Biol.25, 843–854. 10.1007/s00300-002-0428-1
29
MacLennanD. N.FernandesP. G.DalenJ. (2002). A consistent approach to definitions and symbols in fisheries acoustics. ICES J. Marine Sci., 59, 365–369. 10.1006/jmsc.2001.1158
30
MelleW. (2013). Cruise report Cruise no. 2013107. Bergen: IMR.
31
NaylorR. L.HardyR. W.BureauD. P.ChiuA.ElliottM.FarrellA.et al. (2009). Feeding aquaculture in an era of finite resources. Proc. Natl. Acad. Sci.106, 15103–15110. 10.1073/pnas.0905235106
32
ParekhP.DutkiewiczS.FollowsM. J.ItoT. (2006). Atmospheric carbon dioxide in a less dusty world. Geophys. Res. Lett.33, L03610. 10.1029/2005GL025098
33
PaxtonJ. R. (1979). Nominal genera and species of lantern fishes (Family Myctophidae). Contrib. Sci., Nat. Hist. Mus. LA. Cty. 332, 1–28.
34
PotierM.MarsacF.CherelY.LucasV.SabatieR.MauryO.et al. (2007). Forage fauna in the diet of three large pelagic fishes (lancetfish, swordfish and yellowfin tuna) in the western equatorial. Indian Ocean Fisher. Res.83, 60–72. 10.1016/j.fishres.2006.08.020
35
RobisonB. H. (2009). Conservation of deep pelagic biodiversity. Conserv. Biol.23, 847–858. 10.1111/j.1523-1739.2009.01219.x
36
SandersR.HensonS. A.KoskiM.De La RochaC. L.PainterS. C.PoultonA. J.et al. (2014). The biological carbon pump in the North Atlantic. Progr. Oceanogr.129, 200–218. 10.1016/j.pocean.2014.05.005
37
TittensorD. P.MoraC.JetzW.LotzeH. K.RicardD.Vanden BergheE.et al. (2010). Global patterns and predictors of marine biodiversity across taxa. Nature466, 1098–1102. 10.1038/nature09329
38
ValinassabT.PierceG. J.JohannessonK. (2007). Lantern fish (Benthosema pterotum) resources as a target for commercial exploitation in the Oman Sea. J. Appl. Ichthyol. 23, 573–577. 10.1111/j.1439-0426.2007.01034.x
39
van HarenH.ComptonT. J. (2013). Diel Vertical Migration in Deep Sea Plankton Is Finely Tuned to Latitudinal and Seasonal Day Length. PLoS ONE8:e64435. 10.1371/journal.pone.0064435
40
WebbT. J.Vanden BergheE.O'DorR. K. (2010). Biodiversity's big wet secret: The global distribution of marine biological records reveals chronic under-exploration of the deep pelagic ocean. PLoS ONE5:e10223. 10.1371/journal.pone.0010223
41
WormB.HilbornR.BaumJ. K.BranchT. A.CollieJ. S.CostelloC.et al. (2009). Rebuilding Global Fisheries. Science325, 578–585. 10.1126/science.1173146
42
YoolA.PopovaE. E.CowardA. C.BernieD.AndersonT. R. (2013). Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean. Biogeosciences10, 5831–5854. 10.5194/bg-10-5831-2013
Summary
Keywords
mesopelagic community, food provision, climate regulation, biodiversity, benefits Risks
Citation
St. John MA, Borja A, Chust G, Heath M, Grigorov I, Mariani P, Martin AP and Santos RS (2016) A Dark Hole in Our Understanding of Marine Ecosystems and Their Services: Perspectives from the Mesopelagic Community. Front. Mar. Sci. 3:31. doi: 10.3389/fmars.2016.00031
Received
18 January 2016
Accepted
03 March 2016
Published
17 March 2016
Volume
3 - 2016
Edited by
Christos Dimitrios Arvanitidis, Hellenic Centre for Marine Research, Greece
Reviewed by
Athanassios C. Tsikliras, Aristotle University of Thessaloniki, Greece; George Tserpes, Hellenic Centre for Marine Research (HCMR), Greece; Dag Lorents Aksnes, University of Bergen, Norway
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Copyright
© 2016 St. John, Borja, Chust, Heath, Grigorov, Mariani, Martin and Santos.
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Michael A. St. John mstjo@aqua.dtu.dk
This article was submitted to Marine Ecosystem Ecology, a section of the journal Frontiers in Marine Science
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