The conservation of marine ecosystems is at least 20 years behind terrestrial and freshwater ecosystems due to the difficulties in studying and monitoring these dynamic and complex environments. Furthermore, marine environment receive less attention because human impacts are less visible in the sea, and oceans are viewed as global commons. The purpose of the present dissertation is to contribute to the knowledge of marine conservation through the development of three components in natural resources management: inventory, monitoring, and assessment of impacts. I elaborate a multi-taxa inventory, identify key species to monitor, characterize one of the key species, and assess the impacts of the most important fishery in the community-based controlled marine area of the Seri Indians along the Sonoran desert coast of Mexico. A total 657 species of mollusks, echinoderms, sharks, rays, bony fish, sea turtles, sea snake, aquatic birds and marine mammals were recorded in the Seri territory through review of 30 scientific collections housed in museums and universities, literature, and field collections. The fish information was improved through the analysis of 151 traditional Seri names. Fifty species were identified for monitoring ecosystem health. They represent species with a legal status, rare, commercially important, taxa that dominate or characterize entire communities, common taxa, and species recognized in the Seri culture. The annual eelgrass (Zostera marina atam) was selected as a key species inside the Canal de Infiernillo in the Seri territory. Coverage of the eelgrass beds was estimated using aerial photographs, field mapping, and Seri traditional ecological knowledge. The total extent of the eelgrass beds was approximately 6687 ha, which regrew in the same areas during the three-year study, maintaining the same general shapes and sizes. Twenty-six percent of the eelgrass beds overlap with the swimming crab (Callinectes bellicosus) fishing zones. Major impact on this fishery are caused by "ghost" fishing traps, which continue to capture crabs and animals and modify the substrate as they are moved around by currents and accumulate on the sea bottom. Efforts to standardize the use of traps will reduce these impacts on this fishery in the long term.

Distinguishing marine and freshwater animals in the fossil record is a long-standing problem in paleontology. The physiological tolerances of extinct animals usually are inferred from environmental indicators and/or on the physiology of nearest living relatives. These types of evidence are often ambiguous and may be confounded by factors such as post-mortem transport and polymorphism in the living relatives. A solution to this problem is to combine these types of data with analyses of the oxygen isotope compositions of the phosphate (δ¹⁸O(p)) and the carbon isotope compositions of the carbonate (δ¹³C(sc)) of teeth and bones, to determine whether the ingested water and diet, respectively, were fresh or marine. The power of this approach is illustrated here in a study of the early evolution of cetaceans (whales, dolphins and porpoises). Changes in δ¹⁸O(p) and δ¹³C(sc) of the teeth and bones of early cetaceans documented here indicate that fully marine cetaceans existed by the middle Eocene and that some species exploited both marine and freshwater environments. This isotopic approach requires the avoidance of isotopically altered specimens. For this reason, the second component of this work deals with criteria for recognizing isotopically altered fossils. In contrast to one recent study, I found a positive correlation between δ¹⁸O(p) and δ¹⁸O(sc) not only in mammals but also in fish and reptiles. This correlation can be used as a test of whether the original isotopic composition is preserved in fossil specimens. Another approach to this problem is to make analyses of samples taken along growth transect of a fossil tooth or bone. Growth-transect analyses could resolve whether within-species isotopic variation represents differences in preservation or ontogenetic shifts in diet or habitat. In support of this goal, a new method for the analysis of phosphate oxygen is presented. This new method differs from all previous methods in that it involves no chemical reaction, but rather high-temperature (>725°C) equilibrium oxygen isotope exchange between CO₂ and Ag₃PO₄ As the amount of CO₂ is controlled by the analyst, small phosphate samples may be analyzed, making this method potentially useful for growth-transect analyses.

<p> Predicting impact of oil spills on aquatic life requires a better understanding of effects on aquatic organisms, both for single hydrocarbons and for their interactions. In this study, the individual and combined effects of petroleum hydrocarbons phenanthrene (Phen) and dibenzothiophene (DBT) were assessed on the reproductive behavior of the freshwater amphipod <i>Hyalella azteca. </i> Following a 24-h exposure to single PAHs, or an equimolar mixture of Phen-DBT, mate-guarding behavior was assessed at the end of the exposure and during a subsequent 10 min behavioral observation period with the animals in clean water. The endpoints of the study during the behavior observation period were&mdash;time taken to initiate mate-guarding (TIMG), and proportion of time spent in amplexus (PTA). The study demonstrated that the exposure to Phen and DBT reduced the incidence of mate-guarding during the actual exposure period, but not during the observation period. However, whether or not pairs were involved in mate-guarding at the end of the exposure period did affect both TIMG and PTA during the observation period. Thus, the effects of Phen and DBT on amplexus status at the end of the exposure period indirectly affected TIMG and PTA during the observation period. The interaction between Phen and DBT with respect to their effects on mate-guarding varied among the mate-guarding measures. For the amplexus status at the end of the exposure period and for the effect on TIMG, the interaction did not deviate statistically from an additive effect. For PTA, the overall interaction was a synergistic one. This study's findings point out that assessments of hydrocarbon toxicity need to take into account that subtle reproductive behaviors (that may play an important role in population persistence) may be negatively affected. The results also show that the general assumption of additive effects among different PAHs may be an oversimplification.</p>

<p> Since the 1970s halibut size-at-age has decreased in southcentral Alaska; the mechanisms causing decreased size-at-age are unknown. The objectives of this study were to 1) compare size-at-age of port-sampled fish in Homer to survey samples from Gulf of Alaska; 2) assess stable isotope values (&delta;¹³C, &delta;¹⁵N) of halibut by sex, size, location and date; 3) determine mean stable isotope values for prey; and 4) identify prey associated with smaller and larger size-at-age. We used port-sampled halibut from the Homer sport fishery due to the quantity of available carcasses. Port-sampled fish were generally larger than survey sampled fish from the same region. Halibut had a wide range of stable isotope values that varied with all factors. Prey isotope values were wide and overlapping, allowing for distinctions among teleost, cephalopods, crustaceans and amphipods. Older and younger fish of the same size and sex had different proportions of prey assimilated into their muscle.</p>

<p>Reactive oxygen species (ROS) are produced endogenously in all aerobes and are induced by environmental stressors. ROS oxidize and disable essential cellular components such as DNA, proteins, and lipid membranes. Exposure to metals, polycyclic aromatic hydrocarbons (PAHs), and some pesticides can induce oxidative stress in marine invertebrates. All aerobic organisms have a network of antioxidants and enzymes to quench ROS and prevent oxidative damage. This dissertation examines antioxidant and oxidative stress biomarkers in endemic molluscs and crabs from two natural extreme environments: deep-sea hydrothermal vents in the Lau and North Fiji Basin, and cold seeps in the Gulf of Mexico. In addition, the acute toxicity and sub-lethal effects of four insecticides and an herbicide are examined in the estuarine blue crab, <italics>Callinectes sapidus</italics>. Blue crabs are North Carolina's most important fishery species and are frequently found in agricultural drainage ditches, an example of an anthropogenic extreme environment. </p> <p>Total glutathione, catalase, superoxide dismutase, and lipid peroxidation levels were of the same respective order of magnitude in the two vent gastropods, <italics>Alviniconcha</italics> sp. and <italics>Ifremeria nautilei</italics>, and vent mussel, <italics>Bathymodiolus brevior</italics>. These biomarkers activities were similar to those from previous reports on Mid-Atlantic Ridge mussels, except for ~100-fold higher lipid peroxidation levels among Lau molluscs. Principal component analysis (PCA) of mollusc tissue-specific biomarker levels grouped individuals by species rather than by site. </p> <p>Biomarker levels in the seep mussels <italics>Bathymodiolus childressi, B. brooksi</italics>, and <italics>B. heckerae</italics> were similar across species except for elevated foot and gill cytosolic SOD in mussels from MC-640 compared to those from AC-645. PCA of seep mussel biomarker levels differentiated by species with <italics>B. childressi</italics> isolated from <italics>B. brooksi</italics> and <italics>B. heckerae</italics>. The addition of <italics>B. brevior</italics> biomarker data to the PCA showed them grouping around <italics>B. brooksi</italics> and <italics>B. heckerae</italics>. <italics>Bathymodiolus childressi</italics> is ancestral to the other species and contains only methanotrophic endosymbionts. Whether symbionts play a role in alleviating possible toxic conditions remains unknown.</p> <p>Pesticides were acutely toxic to blue crabs in the order of Lambda-cyhalothrin > imidacloprid &#8776; aldicarb > acephate &#8776; Roundup® (glyphosate). Megalopae were almost always more sensitive to pesticides than early stage juveniles. Commercial formations of pesticides generally showed similar toxicity to active ingredients alone. Exposure to LC₂₀ levels of acephate, aldicarb, imidacloprid and Roundup significantly increased the frequency of juvenile mortality after molting. There was no significant change in total glutathione or lipid peroxidation of exposed megalopae. Lambda-cyhalothrin-, imidacloprid-, and aldicarb-based products have the potential to cause acute toxicity and molting-related mortality in shallow creeks and ditches.</p> / Dissertation

I studied the in-water anthropogenic impacts on sea turtles, origins of sea turtles on foraging and developmental areas, their migration routes, and described regionally appropriate conservation needs. Sea turtles inhabiting Baja California waters originate on distant beaches in Japan, Hawaii, and southern Mexico. Results from genetic analyses, flipper tagging and satellite telemetry indicate loggerhead turtles (Caretta caretta) feeding along Baja California's coast are born in Japan and make a transpacific developmental migration of more than 20,000 km, encompassing the entire North Pacific Ocean and that East Pacific green turtles (Chelonia mydas) originate on and return to rookeries in Michoacan, and the Islas Revillagigedo, Mexico. Hawksbill turtles (Eretmochelys imbricata), once the target of a lucrative fishery for their shell, are now extremely scarce and only juveniles were encountered. The region's importance to the biology of sea turtles, regionally and Pacific-wide, warrants urgent conservation action. While protected legally, sea turtles are subject to furtive hunting and incidental catch. Coastal development, pollution, and boat collision are secondary threats. Annual consumption of sea turtles in the region is estimated at between 7,800 and 30,000 animals. Sea turtles are eaten regularly in most coastal communities and turtles are considered an irreplaceable traditional food. The decline of sea turtles in these waters has cost us both ecologically and culturally. Sea turtle recovery in Baja California, as all conservation activities, will be a matter of cultural and social evolution. For recovery to occur, strong, community-based incentives and educational programs are needed. In the near term, increased enforcement efforts, monitoring of mortality, and establishment of sea turtle sanctuaries are among the solutions. Without expansion to include community-specific initiatives such efforts may be futile. A long-term, multi-faceted sea turtle "conservation mosaic" program has been launched, consisting of community-based research on life history and population biology, an international education and public outreach campaign, regional sea turtle conservation areas, a monitoring and stranding network, and several policy initiatives that will permanently protect sea turtles and their habitat.

The fate and occurrence of Giardia and Cryptosporidium were studied in the marine environment to assess their potential for transmission since their transmission to swimmers in fresh waters has been previously documented. The first part of this study was designed to determine the occurrence of Giardia and Cryptosporidium at bathing beaches within the vicinity of an outfall discharging primary treated sewage into Mamala Bay, Hawaii. Sites were monitored monthly and quarterly for parasites by passing 400 liters of marine water through a spun polyproplyene fiber filter. Giardia and Cryptosporidium were detected in primary treated sewage from the Sand Island sewage treatment plant which discharges into Mamala Bay at concentrations of 2,560 cysts and 216 oocysts/liter, respectively. Ala Wai Canal as well as the bathing beaches within the vicinity of the outfall were also found to contain the parasites. The survival of Giardia in marine water was studied in direct sunlight and the dark in marine waters (33- to 35-ppt salinity), canal water (28-ppt salinity) and in phosphate-buffered saline (8-ppt) at 18 to 28°C. Giardia muris was inactivated by 3-logs in the presence of sunlight in marine and canal waters. In comparison, Giardia survive up to 6 hours in PBS under the same conditions. Overall, it appears that salinity and sunlight quickly inactivate Giardia cysts. Thus, Giardia would pose a threat only if the cysts reach the bathing beaches within a few hours. The last phase of this project was designed to develop a more efficient method of collection of cysts and oocysts from water. Methods for the concentration of enteric viruses, Giardia and Cryptosporidium from water requires the use of two different types of filters. This study compared the efficiency of their concentration from tap water and tertiary treated wastewater with a polypropylene fiber cartridge, and the Filterite electronegative and the 1MDS Virosorb electropositive microporous filters. Results indicated that the overall efficiency was greatest for the Filterite filter for both Giardia and Cryptosporidium (p = 0.000762 and p = 0.067069, respectively); and in addition they are easier and faster to process than the polypropylene-wound parasite filter.

The predation pressures on juvenile Haliotis kamtschatkana, northern abalone, in Barkley Sound. British Columbia, were investigated. Thirty-seven potential predators were tested in the laboratory to determine if they would consume juvenile abalone 1- 25 mm shell length (SL). Six of these potential predators consumed > 10 % of the abalone offered to them and were considered major predators. Natural mortality for juvenile H. kanntschatkana was then estimated by outplanting calcein marked and bee tagged hatchery-reared abalone at field sites. Calcein concentrations between 20 40 mg/L produced clear fluorescent marks for 3- 5 mm SL abalone when exposed to a double calcein marking procedure and abalone > 15 mm SL immersed in calcein for 72 h showed the most distinct marks. Recoveries of outplanted abalone were highest (24%) for 15.1- 20 mm juvenile abalone. I recommend outplanting juvenile abalone larger than 12 mm to increase chances of survivorship in the wild.

The deep sea. for a long time. had been perceived as a homogenous and stable environment, with little diversity. The discovery of island habitats such as hot vents. cold seeps and whale carcasses revealed the presence of high biomasses in the deep sea. Species richness on island habitats is low however, compared to the species richness on abyssal plains (Tunnicliffe 1991: Stecher et al. 2003). A study addressing species richness on abyssal plains concludes there to be tens of millions of new species (Grassle and Maciolek 1992). Other authors dispute these numbers and suggest a total deep-sea species richness of approximately half a million (May 1993). The discrepancy in these numbers by multiple orders of magnitude emphasize how under-sampled the deep sea is. The Northeast Pacific is recognized as a biogeographic species province both in the intertidal. shallow subtidal (Valentine 1966: Roy et al. 1994) as well as in hydrothermally active areas (Van Dover et al. 2002). The Northeast Pacific hydrothermally active areas are unique in that they appear to foster single dominant species within ecosystems: e.g. Ridgeia piscesae (Vestimentifera. Annelida) (Southward et al. 1995): Lepetodrilus fucensis (Gastropoda, Mollusca) (McLean 1993). Xylophaga washingiona BARTSCH (Bivalvia. Mollusca) is the only described species of deep-sea wood-boring clams in the Northeast Pacific (Bartsch 1921). We investigated the species richness of deep-sea wood-boring clams (Family Pholadidae. Subfamily Xylophagainae) in the Northeast Pacific by means of strategically placed, experimental wood blocks. The objective of the study was to a) assess the morphological diversity and separate the specimens into distinct morphological taxa: b) to use genetic markers (CO 1. 18S) to discern the genetic diversity within the morphological taxa and c) to elucidate the phylogenetic relationships among the new species. We discovered eight morphological taxa (B. F. G. M. R, T. U. X), defined by a set of characters. previously used to describe new pholad species. The most distinguishing characters were the morphologies of the siphon and mesoplax (accessory plates). The CO1 gene sequences showed little diversity within the morphological Taxa B. F, G. U and X. The 18S gene data split Taxa B and T into B1. B2 and T1, T2, respectively. There was no genetic diversity within 18S sequences of Taxon R. Thus. we discovered at least six new species: Xylophaga species B1. F. G, R. U and Xylopholas species X. I cannot confirm the statuses of Taxa M and T due to missing morphological characters as well as the unavailability of their CO1 sequences. The newly discovered species increase the number of deep-sea, wood-boring species from one to seven, in the Northeast Pacific. Globally, a total of 41 species have been described. Given the discoveries in this study, this number is likely an underestimate of the global species richness of the Xylophagainae. The phylogenetic relationships of the genus leveI remain inconclusive due to too few samples. Species relationships emerged. placing Species G and R as most closely related. as well as B1 and X washingtona. Additional samples from all ocean basins are necessary to further investigate the relationships and origins of the deep-sea woodborers. Future avenues that need to be explored are threefold: a) Ancestry: Has there been one or multiple invasions into the Northeast Pacific, with subsequent adaptive radiations? Where do this/these ancestor species come from? b) Support for Diversity: What mechanisms allow the deep-sea wood-boring clams to co-occur? What are the deep-sea wood-boring clams' micro-niches? c) Effects of Diversity : What is the role of the wood-boring clams in species communities inhabiting deep-sea wood?

Three gastropods occupy a range of habitats along gradients in hydrothermal flux at Juan de Fuca Ridge vents. I examined how these species co-exist and identified mechanisms driving their abundances. First, I measured temperatures and spatial patterns in adult densities of the three species at three distances from vents to test if thermal regime relates to their habitat selection. Lepetodrilus fucensis and Depressigyra globulus were most dense in-vent (0-25 cm) at variable temperatures (10+5°C): 2100 and 240 incl. dm -2 (respectively). Provanna variabilis was most abundant far-vent (51-75 cm: 60 ind. dm 2) at stable temperatures (3±0.5°C). Thermal conditions are key in their habitat selection: behavioural experiments showed that these gastropods select fluid temperatures<18°C. L.fucensis and D. globulus preferred 5-15°C, while P. variabilis preferred 4-12°C. The next studies sought to explain how Lepetodrilus fucensis reaches order of magnitude higher densities in comparison to other gastropods. First. I quantified L. fucensis recruitment and sex ratio patterns to identify innovative life history traits. I meaured size structure and density at in- and far-vent locations. Early postlarval juveniles occupied far-vent at remarkable densities (2419 ind. dm-2). To test for sex ratio biases, I sexed animals from different habitats and sizes. Populations nearest vents hosted the largest females (>6.0 mm), while peripheral habitats were male-biased. A transplant experiment showed that female survivorship and gonad fullness were significantly lower than males in far-vent locations. Sex ratio biases are driven by two mechanisms: females maximize their reproductive output by selecting optimal habitats and suffer relatively higher mortality in low flux. Next, I hypothesized that the Lepetodrilus fucensis gill symbiosis is a key adaptation. I used multiple approaches to determine if the prevalence of the association and relationship to the limpets condition support this hypothesis. FISH probes specific to the 16S rRNA molecule of a gamma-Proteobacteria hybridized where bacteria were present. Direct sequencing using symbiont-specific primers gave a single unambiguous sequence. indicating high specificity. Light and TEM micrographs of gill tissue from a range of species also showed that the symbiosis is ubiquitous. In addition, the gills of in-vent animals had high surface area. dense symbiont populations and healthy tissues, while far-vent animals showed the reverse trend, suggesting that the symbiosis benefits L. fucensis. Carbon fixation by gill tissues was stimulated by inorganic sulfide and related to the abundance of bacteria on the gill. These data indicate a persistent and specific symbiosis that is dependent on access to sulphide. I further examined feeding by Lepetodrilus fucensis to determine if the bacteria contribute to their host's nutrition. The morphology of feeding structures were compared among Lepetodrilus species. L. fucensis exhibited specialized features: the gill is enlarged. the lamellae are free of the mantle. do not narrow and are stabilized by ciliary junctions. The radula and stomach of L. fucensis are also reduced. Shipboard observations confirmed suspension feeding by L. fucensis. In addition, the symbiont may be ingested because its phylotype was well-represented in food material on the gill. The limpet's morphological specializations are consistent with dependence on suspension feeding and/or symbiont farming; however, L. fucensis also grazes. a mechanism likely important in peripheral locations. Lepetodrilus fucensis populations are partitioned by size and sex along environmental gradients near vents. Peripheral populations are dominated by recruits and adults tend to be male: grazing is likely their primary feeding mode. Larger animals form stacks in venting fluids and are female-biased. These populations access suspended particles for food and sulphide, which generates dense symbiont populations for ingestion. Multiple feeding modes sustain high L. fucensis densities in a space-limited environment and may be an innovative strategy that drives its remarkable abundances.