Type
Text
Type
Dissertation
Advisor
Cerrato, Robert | Pikitch, Ellen K | Gobler, Christopher | Frisk, Michael | Essington, Timothy.
Date
2015-08-01
Keywords
Cochlodinium polykrikoides, Ecosystem service, Fisheries, Food webs, Forage Fish, Harmful Algal Blooms | Ecology
Department
Department of Marine and Atmospheric Science.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76010
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Forage fish are small pelagic species (e.g. sardine, anchovy, krill, etc.) that are generally short-lived and exhibit schooling or shoaling behavior. Although these species were once thought to be inexhaustible, they are prone to collapses due to oceanographic factors and overexploitation from fisheries. In addition, the effects of climate change, habitat destruction, pollutants, and harmful algal blooms threaten their conservation. Prior to the work described in this dissertation, no global assessment of the ecological and economic importance of these species had been conducted, despite the fact that these species represent some of the largest fisheries in the world and are prey for many marine predators, including seabirds, marine mammals, and large predatory fish. This dissertation explored the global importance of forage fish species to marine ecosystems and fisheries and elucidated the threats posed from the geographically expanding ichthyotoxic dinoflagellate, Cochlodinium polykrikoides. Using a synthesis of ecosystem models (Ecopath), forage fish were found to contribute a total of $16.9 billion USD to global fisheries value annually. While the global catch value of forage fisheries was $5.6 billion, fisheries supported by forage fish were more than twice as valuable ($11.3 billion). Forage fish also made significant contributions to marine predators, accounting for large fractions of the diets of seabirds, marine mammals and large predatory fish. For example, the median forage fish diet of seabirds in upwelling ecosystems was estimated at 89%. Other indices computed revealed that these predators: 1) often selected forage fish as their most preferred prey item, 2) commonly exhibited specialized feeding strategies, and 3) targeted similar trophic levels of prey as forage fisheries. Toxicity experiments conducted with C. polykrikoides, using three forage species common to the US East Coast, revealed: 1) significant mortalities occurred in both exposed embryos and eleutheroembryos, but that sensitivity differed among fish species and life stages, 2) the first evidence of sublethal impacts to fish, as exposed eleutheroembryos lost and regained their swimming ability following short-term exposures, and 3) the first assessment of behavioral toxicity in larvae following sublethal exposures. Future research should clarify these roles and continue to examine threats to forage fish populations. | 186 pages
Recommended Citation
Rountos, Konstantine John, "Contributions of forage fish species to marine ecosystems and anthropogenic threats to their conservation" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 1973.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/1973