Struktura potravní sítě a trofická ekologie hlubokomořských ryb v Sargasovém moři

• Thesis title in Czech: Struktura potravní sítě a trofická ekologie hlubokomořských ryb v Sargasovém moři
• Thesis title in English: Food web structure and trophic ecology of the deep-sea fishes in the Sargasso Sea
• Key words: Potravní síť, společenstva ryb, stabilní izotopy, potravní guildy, trofické vztahy
• English key words: Trophic structure, fish community, stable isotopes, feeding guilds, trophic pathways,
• Academic year of topic announcement: 2022/2023
• Thesis type: dissertation
• Thesis language: čeština
• Department: Institute for Environmental Studies (31-550)
• Supervisor: RNDr. Petra Horká, Ph.D.
• Author: hidden - assigned by the advisor
• Date of registration: 14.10.2022
• Date of assignment: 14.10.2022
• Advisors: Mgr. Zuzana Musilová, Ph.D.

Preliminary scope of work

Práce je zaměřena na trofickou ekologii ryb v Sargasovém moři. Cílem je popsat strukturu potravní sítě společenstva ryb v tomto unikátním mořském ekosystému, zejména stanovit (1) izotopovou niku bazálních zdrojů potravy a ryb (2) trofickou strukturu společenstva ryb a interakce ve společenstu a (3) celkovou strukturu potravní sítě.

Preliminary scope of work in English

Deep-sea environment is one of the least investigated habitats on Earth, mostly due to the challenging logistics of sampling. The Sargasso Sea in one of the unique pelagic ocean ecosystems where the primary faunistic exploration together with the fish community ecology is still poorly understood. This project focuses on the rare material of fish and pelagic invertebrates collected by the deep-sea cruises in the Sargasso Sea and Azores, and will specifically target the trophic ecology with the overall aim to reconstruct the food web of the pelagic fish community.
The main goal of the proposed project is to provide a comprehensive analysis of a deep-sea food web at the Sargasso Sea region. We aim to reconstruct food web structure and dynamics of the deep-sea fishes community, and to find out what is the primary energy input for the fish community in this unique ecosystem. We will apply stable isotope analysis (isotopic signatures δ¹⁵N and δ¹³C as well as carbon and nitrogen elemental concentrations) to evaluate trophic interactions and trophic niche space of species. Particularly, we aim to provide (1) preliminary description of isotopic composition of various feeding guilds of fishes and food sources on which they rely, (2) analysis of the trophic niche diversity and community relationship, and (3) overall trophic pathways in this ecosystem and to compare the results with other ecological studies in deep-sea ecosystems. We will specifically focus to test the following hypotheses: I) differential specialization of the predatory dragon fishes (Stomiiformes), II) position in the food web of the target mode species, the Silver spinyfin (Diretmus argenteus) - predator or filtrator?, III) comparison of the same species from two discrete locations (Sargasso Sea, Azores), IV) comparison of the trophic ecology between the adult, juvenile and larval stages of the selected species candidates of dee-sea fishes.