Marine Biology Commons^™

Beyond Cortisol: Indicators Of Stress And Negative Feedback In Plasma And Blubber Of Marine Mammals, Jessica Avalos

University of the Pacific Theses and Dissertations

Marine mammals play an important role in ecosystem stability. However, anthropogenic activity is compounding pressure on many already vulnerable populations. A potential consequence of anthropogenic disturbance is physiological stress, which can impact metabolism, immunity, and reproduction, especially if it occurs repeatedly. Previous studies on marine mammals have focused on acute stress, but the impacts of repeated stress are poorly understood. Due to its accessibility on land during haul-outs, the northern elephant seal (Mirounga angustirostris) is a good system in which to study the effects of stress in marine mammals. Stress stimulates the release of glucocorticoid hormones, primarily cortisol. Elevated cortisol …

How Do They Do It? Using Omics Approaches To Explore Metabolic Responses Associated With Hypoxia And Exercise Tolerance In The Deepest Diving Pinniped, Elizabeth R. Piotrowski

University of the Pacific Theses and Dissertations

Marine mammals such as northern elephant seals (NES) routinely experience hypoxemia and ischemia-reperfusion events to many tissues during deep dives with no apparent adverse effects. Adaptations to diving include increased antioxidants and elevated oxygen storage capacity associated with high hemoprotein content in blood and muscle. Despite experiencing decreased oxygen tensions during diving, NES likely rely on the mobilization of large lipids stores and catabolism of fatty acids to provide energy to exercising muscle while diving. To identify potential regulatory mechanisms that may underly hypoxia and exercise tolerance in diving mammals, this study used system-wide approaches to characterize changes in genes …

Impacts Of Plastic Pollution On A Pelagic Marine Mammal, The Northern Elephant Seal, Lauren M. Kashiwabara

University of the Pacific Theses and Dissertations

As plastic pollution increases, top marine predators such as marine mammals are becoming increasingly susceptible to plastic particles and their additives. Plastic particles have been found in gastrointestinal tracts and scat of many marine mammals, and quantifying plastic pollution in those that are pelagic can provide insight into plastic pollution in mesopelagic ecosystems that are just beginning to be analyzed. Adapting well-developed laboratory techniques for microplastic (MP) isolation (i.e. density separation and chemical digestion), I isolated MPs from the scat of the deepest diving pinniped, the northern elephant seal (NES), and found that100% of scat samples (n=11) contained high counts …

Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade

University of the Pacific Theses and Dissertations

Increasing anthropogenic disturbance in marine ecosystems such as fishing, oil-drilling, and noise pollution can have detrimental effects on the reproduction and survival of apex predators such as marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoid (GCs) hormones, which alter expression of target genes encoding metabolic enzymes and other mediators of stress. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. GCs measurements are used to identify wild animals experiencing stress. However, these measurements may not be sensitive enough to distinguish between an …

Structure, Function, And Functional Morphology Of Mitra Idae Melvill 1893 And M. Catalinae Dall 1920, Terry L. West

University of the Pacific Theses and Dissertations

The morphology of the proboscis--particularly the epiproboscis, the feeding behavior, the function(s) of the epiproboscis, and the functional morphology of the epiproboscis, were studied in Mitra idea Melville and fi. catalinae Dall (Gastropoda: Neogastropoda; Mitridae.

In M. idae, the epiproboscis is an extensible muscular J-shaped rod which curves under the odontophore, and lies parallel to the longitudinal axis of the proboscis. A muscular external sheath encloses that portion of the epiproboscis which lies within the proboscis haemacoel; an invaginated muscular-epithelial internal sheath covers the ventral part of the epiproboscis. The dorsal part of the epiproboscis consists principally of longitudinal muscle; …

The Effects Of Predation And Sediment Reworking By The Maldanid Polychaete Axiothella Rubrocincta (Johnson) On Benthic Littoral Microalgae Assemblages, Gary Scott Shusta

University of the Pacific Theses and Dissertations

The taxonomic composition of the diatom assemblages inhabiting the substrate on the mudflat, and the effects of a cohabiting deposit-feeding invertebrate on the diatom assemblage structure are the subjects of this paper. While pelagic diatoms have received considerable attention in the literature to date, comparatively little is known about the ecology and distribution of benthic diatoms are known to be cosmopolitan in their distributions (Alee, 1950). These plants have been found to be opportunistic species in that they are quick to respond to relatively small perturbations in physical conditions. It has also been demonstrated that distinct associations of diatoms exist …

Reproductive Ecology And Population Dynamics Of Two Sympatric Species Of Macoma (Bivalvia), John Gibson Rae Iii

University of the Pacific Theses and Dissertations

Populations of the sympatric intertidal bivalves, Macoma secta and M. nasuta are compared as to reproductive ecology and population dynamics. Histological examination of seasonal gonadal changes indicate that both species undergo dormancy in the winter months and rapid gamete proliferation in the spring. However, the timing of spawning differs. The M. secta population synchronously spawned in August while the M. nasuta population spawned lightly in late spring and more heavily in the fall. Fecundity estimates indicate M. nasuta adds 140% of winter weight in gametes and M. secta only adds 43% of winter weight in gametes. Spat fall was detected …

Fitness Theory And Aspects Of Behavioral Ecology In Two Sympatric Pacurus Species At Dillon Beach, California : Decapoda, Anomura), John Erickson Warner

University of the Pacific Theses and Dissertations

In the present study, aspects of the behavior and ecology of two sympathetic intertidal hermit crabs, Pagurus hirsutiusculus and Pagurus samuelis were studied with the intention of expanding the use of fitness set analysis to other species, particularly extending studies over the entire breeding season.

Population Ecology Of The Littoral Fringe Gastropod Littorina Planaxis In Northern California, Russell James Schmitt

University of the Pacific Theses and Dissertations

Life history patterns of individual organisms are the result of natural selection and should be correlated with particular physical and biological characteristics of habitats in which they live. The littoral fringe is known to be the most severe physical habitat in the intertidal zone, and it is expected that organisms in it should have population characteristics associated with selective response to physical adversity rather than biological interaction. Ecological studies of populations of Littorina planaxis were made in the Dillon Beach and Bodega Head areas. The study localities differed principally in extent of wave exposure rather than geographical location.

Biological Aspects Of Speciation In Three Sympatric Euzonus Species At Dillon Beach, California (Polychaeta: Opheliidae), Steven Rhoads Parke

University of the Pacific Theses and Dissertations

In the present study, information concerning morphology, ecology, fertilization and larval development of three sympatric species of Eusonus is presented. Morphological similarities are reviewed in part I. These similarities correspond with significant lack of variation found in larval development (part IV). Despite these similarities, as well as the ability to cross fertilize their species, the ecological and reproductive isolating mechanisms presented in part II and II provide a positive indication of the existence of three biologically distinct species. A comparative discussion reviews the efficacy of morphological criteria in differentiating the three closely related Euzonus species.

The Functional Morphology And Ecology Of Chone Mollis, Dale Brian Bonar

University of the Pacific Theses and Dissertations

Chone mollis occurs in large numbers in Tomales Bay and is an ecologically important infaunal member of the bay community. As with most marine communities, very little work has been done with individual species of the community. The present study of C. mollis is a contribution towards an understanding of the community as an ecological unit.

This study investigates the structure and function of the tube; tube-building habits; burrowing and locomotion; external anatomy; feeding; and internal anatomy of the muscular, skeletal, vascular, excretory, reproductive, and alimentary systems of C. mollis.

Reproductive Biology Of Thais Emarginata (Deshayes, 1839) And Thais Canaliculata (Dulcos, 1832), Roy Seamands Houston

University of the Pacific Theses and Dissertations

Thais emarginata (Deshayes, 1839) and Thais canaliculata (Dulcos, 1832), are two common Pacific coast gastropods (Family: Muricidae). T. emarginata is found in semi-protected rocky areas from Alaska to Baja California, while T. canaliaulata occurs in quiet bays from Alaska to Monterey Bay, California (Ricketts and Calvin, 1966). Both species occur on rocks and jetties where they can be seen feeding upon barnacles and young mussels. Despite the abundance of these species their reproductive biology has not been examined.

In the present study, the following aspects of the reproductive biology of T. emarginata and T. canalieulata are presented: Relationship of gonadal …

A Discussion Of The Cytherinae (Ostracoda) With Description Of Two New Species, Leslie Edward Watling

University of the Pacific Theses and Dissertations

This paper is concerned with the description of two new ostracod species, and the discussion of their affinities with other species in the subfamily Cytherinae. In this discussion reference is made to the morphological features of several genera. At this point it must be made clear that although the original type descriptions were used, the author has never seen the type specimens. Thus, all discussion is based on these original descriptions as well as on available supplementary material.

Studies On The Gonadal Pigments Of Cryptochiton Stelleri (Middendorff), Robert Eugene Senff

University of the Pacific Theses and Dissertations

The large gumboot chiton, Cryptochiton stelleri, (Middendorf, 1846) annually undergoes a reproductive cycle terminated by spawning in the spring. Cryptochiton stelleri is one of the marine invertebrates which possess carotenoid prognosis. Cryptochiton acquired its carotenoid moiety from the algae upon which it feeds. Following digestion carotenoids are transported to various sites in the body. The mechanisms and routes of this transport, as well as the eventual fate of the carotenoids in nutrition, are unknown. Perhaps storage in the animal occurs because of an inability to eliminate the carotenoids. On the other hand, the presence of carotenoids in the gonads would …

Redescription Of The Adult Water Mite Hydrachna Miliaria And Description Of Its Life History, David Lou Kass

University of the Pacific Theses and Dissertations

During the summer of 1957 the writer became interested in water mites while collecting insects in an unnamed pond (see map in appendix) near Tomales, California. It was noted during that period that specimens of a giant water-bug, Lethocerus americanus Leidy (1847) had many larval mites attached to their ventral sides, and the lack of information concerning these animals and their life histories stimulated interest in investigating the problem detailed in this thesis. This work was begun in the summer of 1957 and has continued through the summer of 1959 and 1960.

Due to the lack of information and lack …

A Physiological Comparison Of Isopods In The Transition From A Marine To A Terrestrial Habitat : With Notes On Their Morphology And Behavior, Gary John Brusca

University of the Pacific Theses and Dissertations

This study is of five species of isopods common to the Dillon Beach area, each of which represents a different level in the transition toward land life. Cirolana harfordi was used as a completely marine form. Idothea (Pentidotea) wosnesenskii represents a step toward land life as it inhabits an area uncovered by most low tides. Ligia occidentalis is found in the splash zone, receiving spray from the action of the surf. This illustrates another, higher, level in the transition. Alloniscus perconvexus was the fourth species studied. It is commonly found burrowed in the sand in the area of the berm, …