• European Marine Science
• Other research productsclose
• 2018-2022close
• English close
• eScholarship - University of California close
• European Marine Science close

Spatial management is a popular tool for resource managers to protect and conserve natural resources. However, a number of emerging threats are testing the ability of these tools to address management needs. Marine protected areas and slow speed zones are popular tools employed by resource managers to mitigate anthropogenic threats; however climate change and whale ship strikes represent new threats that may complicate the benefits of these tools. This dissertation examines the efficacy of incentivizing slow vessel transits to reduce cetacean mortality risk and the application of MPAs to mitigate climate change. A trial program to monetarily incentivize slow transits through the Santa Barbara Channel showed high compliance compared to a similar voluntary program. During incentivized transits, the large majority of ships maintained a 12 knot transit speed as determined by the program guidelines. An incentivized program may be key in reducing risk to whale mortality and reducing ships speeds; however scaling up this program may face financial difficulty.Marine Protected Areas have been claimed to offer additional protection to areas affected by climate change. However, a recent warm water marine heatwave changed the fish community’s abundance, biodiversity, and recruitment around the Channel Islands. While the ecological community changes across strong longitudinal biogeographic patterns, forecasts built from GLMs with environmental conditions predict shifts in species abundance. Upwelling and cool waters coming to the surface may mitigate warming ocean conditions in the region but marine protected areas showed no increased resilience to acute climate affects like marine heatwaves.

With the ubiquity of parasites, many hosts have been selected to decrease parasite infection success by employing behavioral defenses, such as avoidance of infected habitats/conspecifics, grooming, grouping, altering swimming behavior, or even self-inducing behavioral fevers. California killifish, Fundulus parvipinnis – common to southern California and Baja California estuaries – are typically exposed to several trematode species that use them as 2nd intermediate hosts. At least one of these trematodes substantially impacts killifish fitness. We also know killifish likely perceive trematode infectious propagules (cercariae). However, we do not know whether they employ behavioral defenses. We experimentally exposed killifish (originating from two San Diego wetlands) individually and in groups to two of their trematode species: Euhaplorchis californiensis – which infects the killifish brain and manipulates host behavior to increase predation rates – and Small Cyathocotylid, which infects connective and muscle tissues. To assess killifish behavioral response to exposure, we quantified several behavioral traits: average number/type of potential defensive behaviors (PDBs), activity, vertical position in the water column and group size before and during exposure to parasites. Our results showed that killifish individually-exposed (both previously infected and naïve) to parasites increase their average number of PDBs, but not their activity. However, in groups, parasite-exposed killifish increase both their average number of PDBs and activity. Conversely, neither average vertical position (in either experiment) nor group size was influenced by parasite exposure. In sum, parasites can alter killifish behavior after infection, but also during anti-parasite behavioral defense, with implications for host-parasite coevolution, and host social and ecological interactions.

Richly productive polar marine ecosystems are hypothesized to have evolved within the last ~30 million years through the rise of diatoms to ecological dominance and diversification of distinctive polar fish, sea birds, seals and whales. Today, short diatom-based food chains support substantial fish biomass, but whether polar fish production is high enough to sustain current industrial fishing is unknown. To this end, we compared ichthyolith accumulation rates (IAR), a proxy for fish production, across ocean ecosystems to trace the development of global fisheries stocks over the past 1.8 million years. We find that the magnitude of polar fish production, based on the flux of fish teeth to deep-sea sediments, is an order of magnitude lower than seen in subtropical and tropical sites. We suggest that polar fish production is systematically suppressed by extreme seasonality, phenological mismatch, low functional redundancy, and extreme glacial-interglacial climatic variability in the high latitude oceans. Comparisons of our Pleistocene data to similar records from the Eocene and Oligocene oceans (~42-28 Ma) show that fish production in high latitudes has been consistently low for the last 30-40 Ma relative to most of the tropical and subtropical locations. We conclude that the stock crashes observed in the polar regions over the past several decades reflect overexploitation of ecosystems that have had low fish production for tens of millions of years.

Mesopelagic fishes are of utmost importance to the health of global oceanic ecosystems. These fishes comprise the largest known marine biomass, and are a vital source of food many economically important fish and marine mammals. Further, they serve as a major component of the biological carbon pump, moving food items through the water column via diel migration. Though significant effort has gone into understanding species diversity, and positioning in marine food webs, the microbial component of these animals remains poorly characterized. Symbiotic microbial populations associated with the gastrointestinal (GI) tract assist the host with nutrient uptake, digestion, defense against pathogenic microbes, but can also be detrimental to host health as parasites or pathogens. This study investigates the normal intestinal microbiota of wild mesopelagic fish to determine community diversity and distribution across multiple host families with varying migratory and dietary lifestyles. The results presented here indicate that midwater fish have unique microbial communities from fish of other pelagic zones, where, for example, mesopelagic hosts show enrichment in Betaproteobacteria and Gammaproteobacteria microbial classes. Within mesopelagic fish families, major differences were seen: Gonostomatidae are enriched in three Mycoplasma taxa, Stomiidae had highest alpha diversity, Melamphaidae had the highest abundance of Planctomycetes, and Myctophidae gut communities were enriched in Betaproteobacteria. This study brings new understanding to the microbial ecology of the mesopelagic, and demonstrates that despite sharing space in the water column, mesopelagic fishes contain different microbial communities. Clearly, life history traits must be considered in addition to environment in order to better understand the mesopelagic ecosystem. Mesopelagic fishes are of utmost importance to the health of global oceanic ecosystems. These fishes comprise the largest known marine biomass, and are a vital source of food many economically important fish and marine mammals. Further, they serve as a major component of the biological carbon pump, moving food items through the water column via diel migration. Though significant effort has gone into understanding species diversity, and positioning in marine food webs, the microbial component of these animals remains poorly characterized. Symbiotic microbial populations associated with the gastrointestinal (GI) tract assist the host with nutrient uptake, digestion, defense against pathogenic microbes, but can also be detrimental to host health as parasites or pathogens. This study investigates the normal intestinal microbiota of wild mesopelagic fish to determine community diversity and distribution across multiple host families with varying migratory and dietary lifestyles. The results presented here indicate that midwater fish have unique microbial communities from fish of other pelagic zones, where, for example, mesopelagic hosts show enrichment in Betaproteobacteria and Gammaproteobacteria microbial classes. Within mesopelagic fish families, major differences were seen: Gonostomatidae are enriched in three Mycoplasma taxa, Stomiidae had highest alpha diversity, Melamphaidae had the highest abundance of Planctomycetes, and Myctophidae gut communities were enriched in Betaproteobacteria. This study brings new understanding to the microbial ecology of the mesopelagic, and demonstrates that despite sharing space in the water column, mesopelagic fishes contain different microbial communities. Clearly, life history traits must be considered in addition to environment in order to better understand the mesopelagic ecosystem.

Early American notions of sympathy, largely shaped by Adam Smith’s theory of rational self-interest and fellow feeling, undergird the period’s dominant narrative tropes, socio-political philosophies, and economic ideologies. In this dissertation, I argue that investments in sympathy structure two “domestic” cultural ideals on a watery globe. The first ideal is of a seamlessly productive shipboard society. The second ideal is of an essentially familial national order. To advance these ideals, common sailors, women writers, and political policymakers uphold sympathy as a corrective to sea-based geological or cultural unruliness. In other words, each asserts that domestic stability in a transoceanic system may be gained via a perfection of moral feeling. As I show in two sections, these discrete sentimental narratives on land and at sea confirm antebellum domesticity’s oceanic entanglements. My first section highlights a shipboard domestic ideal that results from oceanic labors that power a U.S.-backed oceanic economy. Specifically, isolated vessels’ socio-material structures direct sailors’ bodies towards affectively cohesive labor. In short, proper feeling at sea is a technical skill as well as a social one. In this system, ideal “sentimental seamen” know exactly how to feel, how to labor, and how to describe those feeling labors. Sailors use novel materialist, labor-based sentimental forms to stake their relative claims to this economic and social ideal. Ultimately, sentimental seamen embody the forms of regulated and monetized feeling that structure age of sail vessels as historical and literary spaces. My second section tracks an antebellum domestic ideal that results from the nation’s reliance on oceanic cultures and economies. Namely, landed writers debate the domestic nation’s place in a “family of nations” via competing definitions of the “villain of all nations.” Within these debates, “pirates of sympathy” are maritime subjects whose incompatibility with state power is due to their supposed incapacity for moral feeling. For some, such figures’ removal protects an ideal national family; for others, the pirate embodies the effects of state violence. As I conclude, this figure’s pervasive literary-historical presence reflects the antebellum era’s shifting and conflicting moral compasses, particularly in relation to maritime slavery and its inheritances. In tracking sentimental seamen and pirates of sympathy, I place two “domestic” ideals on a watery globe. One is a model for ideal domestic laborers at sea. The other is a foil for ideal domestic citizens on land. Both of these figures are defined by their relation to interior, domestic attachments that ripple across and within transoceanic space. In turn, the study of sentimental seamen and pirates of sympathy provide a glimpse of a field I am tentatively calling “terraqueous domestic studies.” Overall, this field treats early American domestic interiority and attachment as fashioned by earth and water together.