Periodic Reporting for period 2 - SUMMER (Sustainable management of mesopelagic resources)
Periodo di rendicontazione: 2021-03-01 al 2022-08-31
The objective of SUMMER is to establish a protocol to accurately estimate mesopelagic fish biomass, quantify the ecosystem services provided by the mesopelagic community (food for aquaculture, for humans, for other wild fish, climate regulation and potential for bioactive compounds) and develop a decision support tool to quantitatively balance the trade-offs between the different services for any given exploitation scenario.
With a potential biomass of mesopelagic fish of 10 times more than all other fish together, we have to evaluate whether and how mesopelagic resources can be exploited without compromising the essential ecosystem services they provide. As the mesopelagic is among the last untouched ecosystems of the planet, this is the last chance and first time to do things in the right way, i.e. to first obtain scientifically sound data, create models and exploitation scenarios and only then - if regarded possible from an ecological and economic point of view - exploit in a sustainable manner.
With a potential biomass of mesopelagic fish of 10 times more than all other fish together, we have to evaluate whether and how mesopelagic resources can be exploited without compromising the essential ecosystem services they provide. As the mesopelagic is among the last untouched ecosystems of the planet, this is the last chance and first time to do things in the right way, i.e. to first obtain scientifically sound data, create models and exploitation scenarios and only then - if regarded possible from an ecological and economic point of view - exploit in a sustainable manner.
This report covers project work performed from the start of the project (September 2019) up to month 36. One relevant project activity has been the review and compilation of existing knowledge (published scientific literature and datasets) concerning the mesopelagic zone. This includes to establish the main predator species and preys of mesopelagic species. Project work further included a preliminary assessment on the role of mesopelagic fishes regarding carbon flux within the ecosystem. In this period the relative biodiversity of different sea areas has also been analysed (Barent Sea, Bay of Biscay Atlantic Western waters and Mediterranean) using different bootstrapping techniques of diversity indexes, and none-invasive eDNA analyses. We have also confirmed how applying eDNA to mesopelagic and bathypelagic (ca. down to 2000 m depth) water samples is able to provide information about the fish community inhabiting these hard-to-reach environments. It has also been confirmed how applying the daily egg production method (DEPM) to a particular species of mesopelagic fish, Maurolicus muelleri, in part of its spawning area in the Bay of Biscay is an alternative methodology to estimate spawning stock biomass.
In terms of the carbon transport, we highlight how little is known about the physiological ecology of mesopelagic fish, trophic pathways within the mesopelagic food web, and how these link to primary production in the surface ocean. However, in order to understand the main uncertainties SUMMER has developed and online tool (SUMMER fish estimator (shinyapps.io)) to assess the impact of the main factors influencing the total fish biomass. Regarding these active fluxes and based on a end to end model, it has been obtained how that migratory mesopelagic fish are responsible for export of about 1.39 PgC y-1, which represents about 9-28% of the total export of carbon to the twilight zone.
Regarding the potential availability of the Ocean Twilight Zone (OTZ) as a source of PUFA (e.g Omega-3) novel insights into the identity and biogeography of potential microbial omega-3 producers has been developed based on metagenomic data mining . However, the exact products of the putative omega-3 biosynthetic gene clusters identified remain unknown and should be assessed further to verify their ability to produce these fatty acids. Also, most of the identified candidates remain uncultured, which implies that this is not a short-term route to obtain microbial PUFA suppliers. With all the available information an economic analysis of it is worth to exploit or not the OTZ has been performed. Result is clearly driven by the uncertainty, in terms of the ecological effects on other species, carbon sequestration and provisioning of fishmeal and fish oil, and even further on the economic parameters of the evaluation (i.e. prices of all these ecosystem services). Nevertheless, results suggest that currently the nonexploitation or low exploitation rates are preferred than a generalized commercial exploitation. An online tool to analyse different exploitation rates of mesopelagic fish has been developed (in this reporting period) and will be delivered in the next reporting period
Within this period SUMMER partners have published 26 peer-reviewed articles and 7 are under review. 21 data resources were published in open access in RP2, including georeferenced data archived at PANGAEA, genetic resources published via GenBank’s Short Read Archive, and data and code deposited at GitHub with DOI registration at Zenodo. SUMMER datasets at PANGAEA are now also findable through the Group of Earth Observations System of System (GEOSS) Portal hosted by the European Space Agency (ESA).
In terms of the carbon transport, we highlight how little is known about the physiological ecology of mesopelagic fish, trophic pathways within the mesopelagic food web, and how these link to primary production in the surface ocean. However, in order to understand the main uncertainties SUMMER has developed and online tool (SUMMER fish estimator (shinyapps.io)) to assess the impact of the main factors influencing the total fish biomass. Regarding these active fluxes and based on a end to end model, it has been obtained how that migratory mesopelagic fish are responsible for export of about 1.39 PgC y-1, which represents about 9-28% of the total export of carbon to the twilight zone.
Regarding the potential availability of the Ocean Twilight Zone (OTZ) as a source of PUFA (e.g Omega-3) novel insights into the identity and biogeography of potential microbial omega-3 producers has been developed based on metagenomic data mining . However, the exact products of the putative omega-3 biosynthetic gene clusters identified remain unknown and should be assessed further to verify their ability to produce these fatty acids. Also, most of the identified candidates remain uncultured, which implies that this is not a short-term route to obtain microbial PUFA suppliers. With all the available information an economic analysis of it is worth to exploit or not the OTZ has been performed. Result is clearly driven by the uncertainty, in terms of the ecological effects on other species, carbon sequestration and provisioning of fishmeal and fish oil, and even further on the economic parameters of the evaluation (i.e. prices of all these ecosystem services). Nevertheless, results suggest that currently the nonexploitation or low exploitation rates are preferred than a generalized commercial exploitation. An online tool to analyse different exploitation rates of mesopelagic fish has been developed (in this reporting period) and will be delivered in the next reporting period
Within this period SUMMER partners have published 26 peer-reviewed articles and 7 are under review. 21 data resources were published in open access in RP2, including georeferenced data archived at PANGAEA, genetic resources published via GenBank’s Short Read Archive, and data and code deposited at GitHub with DOI registration at Zenodo. SUMMER datasets at PANGAEA are now also findable through the Group of Earth Observations System of System (GEOSS) Portal hosted by the European Space Agency (ESA).
The mesopelagic layer (200-1000 m water depth), with a potential biomass of 10.000 million tonnes, is largely unknown. The final aim of SUMMER is to establish how to calculate (estimate) biomass, their aggregation levels, but also to give an answer to the question: To fish or not fish in there. This last is an important message for society given that as a hidden ecosystem, society may not be aware of the services they are currently providing and of the options that we have on exploiting them. Make society aware of them is also a mayor objective of SUMMER.
So far, it has been obtained new insight in terms of biodiversity of this sea layer, carbon fluxes and therefore the role of the OTZ in the carbon sequestration, and specifically of the diel vertical migration of mesopelagic fishes. Based on these results, a tradeoff analysis of the ecosystem services currently provided by the mesopelagic layer and their potential under exploitation has been performed. SUMMER has also tested and validated methods to estimate abundance of biomasses of mesopelagic fishes. Based on that the two main objectives of SUMMER are on track: How to estimate biomass and answer the question of fishing them or not, from the social perspective. It is acknowledged, that results are still under big uncertainties, but SUMMER is on track to reduce them in the next reporting period.
So far, it has been obtained new insight in terms of biodiversity of this sea layer, carbon fluxes and therefore the role of the OTZ in the carbon sequestration, and specifically of the diel vertical migration of mesopelagic fishes. Based on these results, a tradeoff analysis of the ecosystem services currently provided by the mesopelagic layer and their potential under exploitation has been performed. SUMMER has also tested and validated methods to estimate abundance of biomasses of mesopelagic fishes. Based on that the two main objectives of SUMMER are on track: How to estimate biomass and answer the question of fishing them or not, from the social perspective. It is acknowledged, that results are still under big uncertainties, but SUMMER is on track to reduce them in the next reporting period.