Use the filters below to find awards made to CSU students by Program, Campus, or Year.
COAST Award Program
Eastern Pacific Ocean Conference, Mt. Hood, OR
Benthic microplastic distribution in Humboldt Bay, northern California: a comparative study of surface sediments based on proximity from the shore
Plastic production and use has increased steadily over the last century primarily because of plastic’s resistance to corrosion and low production costs. Plastics enter the marine environment from non-point sources such as rivers, wind, and fishing activities, and point-sources like sewage treatment plants, dumping, and landfills. This research focuses on microplastics (MPs), specifically those within the size range of 0.335 to 5 mm, because of the uptake potential by detrital and filter feeding organisms. Quantifying the amount of MPs in the marine environment is crucial because bioaccumulation of plastics in marine life can affect humans who consume marine organisms. This study compares the concentration of MPs in sediments between the intertidal and subtidal environments of Humboldt Bay, California. We hypothesized that the intertidal samples would have higher MP concentrations due to their proximity to shore and increased anthropogenic activity. Sediment samples were collected using hand corers in the intertidal region and a Smith McIntyre grab in the subtidal region. Organic material in the samples was oxidized using 30% hydrogen peroxide, then a density differentiation technique was used to separate plastics for further microscope identification. Preliminary results show that about 95% of MPs found in sediment are microfibers and the remaining 5% of MPs are degraded hard plastic. To date, more MPs have been found in the subtidal region than the intertidal region, with 980 MP particles recovered in the subtidal region and 340 MP particles recovered in the intertidal region. This study confirms the presence of microplastics within Humboldt Bay, and defines their distribution with proximity to shoreline. These results can be used by the community to update recycling practices, wastewater treatment procedures to mitigate microfibers, and raise awareness about marine life ingestion of plastics.
American Association for the Advancement of Science, Washington, DC
Vascularization of male blue rockfish (Sebastes mystinus) urinary bladders
Rockfish support one of the largest fisheries in California. Due to overharvesting, the California Department of Fish and Wildlife began closing the fishery from January to February in 2002 to protect females giving birth. Many male species of rockfish including blue rockfish (Sebastes mystinus) display courtship behavior prior to copulation. It has been hypothesized that pheromones may be released in the urine during courtship, thus playing a role in mate selection. In another scorpaeniform, pheromone release from the urinary bladder is associated with arterial vascularization. We hypothesized that male blue rockfish urinary bladders would be larger and have more vascularization than females. Male blue rockfish (21.23 ± 0.89 cm SL; mean ± SEM; n = 6) had urinary bladders that were 1.87 ± 0.53 cm in length, whereas females (24.33 ± 1.41 cm SL; n = 6) had urinary bladders that were 1.87 ± 0.53 cm in length. Male urinary bladder somatic index (urinary bladder weight/body weight; UBI) was significantly (p = 0.004) greater than female UBI (male 0.162 ± 0.019%, female of 0.022 ± 0.005%). Additionally, erythrocyte clusters (i.e., blood cells within arteries) were counted within the urinary bladder lumen. Males had significantly (p < 0.0001) greater vascularization within the urinary bladder (males 109.33 ± 4.72 clusters in cross section of the bladder, females 25.17 ± 1.66 clusters). This study increases our understanding of rockfish reproduction and provides a novel approach in investigating pheromone release in teleost fish.
Geological Society of America Annual Meeting, Indianapolis, IN
The implementation and use of next generation science standards-based tactile models in the K-12 educational system
In recent years, there has been a lack of Earth and Space Science (ESS) education in the K-12 system, furthermore the vast majority science education classes have centered on passive learning through lecture and textbook assignments. Scientific lab classes are often taught with well laid out science experiments that give little room for deviation from the expected outcome. This ultimately leads to a deficient understanding of how science is conducted in the real world and a high failure rate of STEM fields at the college and university level. The Next Generation Science Standards (NGSS) intends to correct the shortfall of science education by encouraging active participation and collaboration in the classroom. Within these new standards, ESS is given the same amount of content as the typical core sciences of Chemistry, Biology, and Physics. The development and usage of models to represent Earth’s processes are another benefit of the NGSS which helps students become an active participant in the classroom. This project focuses on the construction of three Earth science models for use in the K-12 classroom: an ocean garbage patch model, a glacier model, and a sinkhole model. Models are an important way for students to connect to processes that are too large, too slow, or too far away for students to observe on their own. Therefore this project also includes the design of NGSS-aligned lesson plans to accompany these models that aim to engage students in the scientific method; observation, testing, and proving a hypothesis.
American Geophysical Union, Washington D.C.
Using physical and chemical sediment characteristics to distinguish fluvial and oceanic event deposits within mid-shelf depocenters
Continental shelf stratigraphy can preserve a high-resolution record of episodic events driven by terrestrial, oceanographic and/or climate processes. Along river dominated margins, episodic events often result from fluvial floods, which produce distinct deposits on the shelf. However, for the small mountainous river systems along the US Pacific coast, storms also drive energetic ocean conditions that can increase sediment remobilization from waves and currents. Presumably, deposits from fluvial floods and wave-supported remobilization events would impact seabed processes differently, and these differences may inform our understanding of the role event deposits play in biogeochemical processes and stratigraphy. In this study we demonstrate a means by which these different types of episodic event deposits may be distinguished based on physical and chemical sediment characteristics. We collected and analyzed cores from the Monterey Bay shelf along the central California coast, focusing on areas proximal to the Salinas and Pajaro Rivers. Sediment analyses included bulk density, sedimentary fabric (CT imagery), grain size, X-ray diffraction (XRD), and X-ray fluorescence (XRF). Age control was provided through 210Pb/137Cs and 14C geochronology. We identified two-types of event deposits: Type 1, identified in upper sections of both cores, is characterized by uniform 210Pb activity with depth, increases in coarse silt and fine sand, yet lacks discernable sedimentary fabric such as bedding or laminations. Type 2 was defined primarily by sedimentary fabric (sharp contacts and internal laminations), alternating high and low bulk density layers, and increases in sand. Both types display a change in element concentrations from non-event deposition, however the changes in elemental composition are different between the cores reflecting a unique watershed signal. The Type 1 deposits we interpret to represent the combined effect of fluvial floods and shelf remobilization in wave-supported gravity flows that occurred from oceanic floods during the strong El Niño winters in the 1980s and 1990s. Type 2 deposits represent rapid settling out of terrestrially derived plumes from extreme fluvial floods such as those in 1861-1862. This study demonstrates the possibility of distinguishing between fluvial flood and wave remobilized event-deposits along the mid shelf. This distinction may provide insight into event frequency, as well as a basis to understand how these different types of episodic events may impact biogeochemical cycles.
Society for Integrative and Comparative Biology, Tampa, FL
Stayin’ alive? Assessing the ability of an intertidal seaweed to recover from repeated exposure to desiccation and high temperatures during low tide
Silvetia compressa, a canopy-forming alga, plays a vital role in rocky intertidal ecosystems as a primary producer and habitat for animals. Intertidal organisms are under seawater at high tide and exposed to terrestrial conditions at low tide. Stressors such as wind and heat during low tide can negatively affect algal physiology and subsequently biomass and canopy cover. We manipulated hydration level (values down to 17% wet mass) and body temperature (low mean = 22.79°C, high mean = 30.49°C) over two simulated low light low tides, and monitored the effect on biomass and maximum quantum yield (MQY: a measure of photosynthetic potential) over three days of recovery in simulated high tide conditions. At the end of the second low tide, hydration status was positively correlated with MQY in both low (r = 0.92) and high (r = 0.94) temperature treatments. Following 84 hours of recovery, biomass loss was minimal and not strongly associated with low tide temperature or desiccation and negative effects of desiccation on MQY disappeared, but on average, MQY in high temperature treatments was only 91.6% of that in low temperature treatments. Temporary MQY decreases following low tide desiccation indicate a reduced ability to produce sugar which could affect growth. Repeated exposure to warm low tides could slowly lower an individual’s maximum attainable photosynthetic potential. The combination of dry and warm days could ultimately lead to a decrease in canopy cover, exposing understory organisms to harsh low tide conditions with long term effects on community structure and function.
Filtration along a reticulated mesh, anatomy predicts feeding ecology in neonatal whale sharks, Rhincodon typus
The largest fish in the ocean, Rhincodon typus (Whale Shark), is one of three filter-feeding sharks. While a few studies have predicted the filtration mechanism used by R. typus, none of these studies have successfully verified this mechanism in either a live or model animal. In addition, no studies have predicted the prey selectivity in a neonatal whale shark. The objective of this study was to explore how the morphology of the filter pad separates food particles from the water. We documented the filter anatomy in neonatal whale shark specimens and calculated the freestream and transverse flow through the buccal cavity and filter pores respectively. We then created anatomically correct, scaled 3D physical models of the filter pad reticulated mesh and inserted the printed filters into a physical model of a whale shark buccal cavity. We ran a series of filtration experiments using microspheres (60 μm - 340 μm) that represent the full size range of potential zooplankton prey. Modeling the neonatal specimen allows us the rare opportunity to study feeding mechanisms in an animal that is CITES protected and rare in aquaria. Understanding the mechanism of filtration and prey selectivity in neonatal whale sharks helps to predict their ecology and likely habitat usage in the wild.
National Conference on Undergraduate Research, Kennesaw, GA
Say cheese: utilization of trail cameras brings new monitoring techniques to endangered shorebird recovery on Ormond Beach
The Pacific coast population of the western snowy plover (WSP) (Charadrius nivosus nivosus) is a small shorebird that nests and winters on the west coast beaches of North America. Although the species has evolved to survive in a dynamic beach environment, it was listed as federally threatened in 1993 because of low population numbers due to loss of habitat, human disturbance, and predation. The United States Fish and Wildlife Service (USFWS) recovery plan requires nesting outcome to be tracked to monitor progress towards species recovery goals. Standard methods rely on human-orientated monitoring instead of utilizing available technology to remotely track nesting outcome.
Trail cameras were used concurrently with traditional techniques for the 2018 nesting season on Ormond Beach in Oxnard, California. Nearly 4,000 hours were logged with over 100 predator sightings. Twelve out of 35 nests had cameras for the entire brood cycle (28 days) and one had a camera for part of the time. Out of these nests, cameras captured a definitive outcome for 67% of them (8 nests) including exact time of hatch (4 nests). Depredation of chicks was documented for 2 nests after hatching. Monitors directly witnessed only 32% of outcomes (7 nests). Two were observed actively hatching, four were seen with chicks in or near the nest, and one was spotted depredated. The remaining nest outcomes were established using deduction (68%).
Eastern Pacific Ocean Conference, Mt. Hood, OR
Distribution of microplastics at the surface and within the water column in Humboldt Bay, northern California
Plastic is a commonly used, man-made material that is highly durable, easy to produce, and used widely throughout society. The persistence of plastics results in their introduction to the oceans via river runoff from urban and industrial areas, intentional dumping, and fishing practices. This study investigates microplastics (MPs) in the size range of 0.335 to 5 mm. MPs directly affect marine ecosystems, as they are mistaken for food by marine organisms and are then transferred to humans when we consume seafood. MP concentration in the water column can vary due to river input, tidal flux, and source proximity. We hypothesized that the highest concentration of MPs within Humboldt Bay (HB) in northern California would be found in the harbor entrance (Entrance Bay), which is adjacent to a sewage treatment plant and near a solid waste transfer station. We surveyed MP concentrations within the water column and surface layer in the three sub-basins of HB. Surface and water column samples were obtained using 0.335-mm mesh neuston and ring nets, respectively. Organic material in the samples was removed via oxidation with 30% hydrogen peroxide. Density separation techniques were then used to separate plastics for microscope analysis. Preliminary results do not support our hypothesis, as air-sea interface MP concentrations are highest in North Bay (6.25x10-5 ± 4.03x10-5 plastic particles per liter (ppL)), followed by South Bay (3.48x10-5 ± 1.04x10-5 ppL), and lowest within Entrance Bay (2.23x10-5 ± 0.87x10-5 ppL). Within the water column, the highest average concentration of MPs was found in South Bay (5.81x10-5 ± 11.89x10-5 ppL), with lower concentrations in Entrance Bay (1.46x10-5 ± 0.84x10-5 ppL) and North Bay (1.21x10-5 ± 0.87x10-5 ppL). This study can help the public understand the quantity of plastic contained within HB, where it is most concentrated, and possible mitigation practices.
Association for the Sciences of Limnology and Oceanography Aquatic Science Meeting, San Juan, Puerto Rico
Characterization of ocean conditions in Monterey Bay, CA to support fisheries ecosystem research
Prevailing ocean conditions were characterized as part of NOAAs National Marine Fisheries Service 2018 Rockfish Recruitment and Ecosystem Assessment survey conducted along the California coast. Seventeen stations within Monterey Bay and the adjacent coast were sampled 7-9 June. It was expected that nekton abundance would be related to the underlying ocean conditions and chlorophyll-a (chl) concentrations. At each station, a sampling rosette equipped with a conductivity, temperature and depth (CTD) package was deployed to a maximum depth of 500 meters. Discrete water samples were collected for analysis of in vitro chl. At three locations, epipelagic micronekton were sampled by midwater trawl. Patterns of relatively cold water (11C) and elevated salinity (>33.8), indicative of upwelling, were observed in northern Monterey Bay. A north–south gradient of increasing chl from <5mg/m3 to >10 mg/m3 was observed. Greater than 80% of chl was found in cells >5-um diameter in the northern bay while in the south, only half were found in in cells >5-um. North-south declining abundance trends of the squid Doryteuthis opalescens and euphausid Thysanoessa spinifera were observed across the three trawl stations. High abundances of two jellyfish species, Chrysaora fuscescens and Aurelia spp. were encountered within Monterey Bay and interfered with trawl operations. At the three trawl stations that were sampled the highest abundances of jellyfish were found in the north. These results suggest that nekton and jellyfish abundances were not positively associated with elevated chl.
Benthic Ecology Meeting, St. Johns, Newfoundland, Canada
Evaluating the Labrisomus xanti populations on Santa Catalina Island by determining age, size ranges, densities, and habitat preference
In 2015 a strong El Niño Southern Oscillation event began affecting the NE Pacific Ocean. With increasing water temperatures, new marine species were able to expand north of native ranges and settle in new habitats. Santa Catalina Island, specifically, became home to many new species of fishes. The first sighting of the species Labrisomus xanti, or largemouth blenny, on Catalina was October 2015 and since that time these blennies have been sighted around the island. To investigate whether this species has established on Catalina, largemouth blennies were counted, sized and their sex was reported at three sites along the island. At each site, transects were placed at depths ranging from 1.5 to 6meters. Substrate type (sand, gravel, cobble, boulders 10-100cm, bench) was recorded along each transect. Observations showed that there are multiple size ranges among sites, depths and sexes of largemouth blennies. Individuals were then collected and aged based on otolith extractions. We found a significant difference in densities among sites and habitat preference was significant based on substrate. These densities, ages and habitat preferences are important observations because if largemouth blennies are established and settling permanently on Catalina they may begin competing with native species for territory and resources.
Phycological Society of America and International Society of Protistologists, Vancouver, BC, Canada
Spatial patterns of genetic structure in Mastocarpus stellatus (Rhodophyta)
Mastocarpus stellatus occurs in dense patches on many rocky shores on both eastern and western coastlines of the North Atlantic Ocean. The life cycle of M. stellatus consists of sexual generations alternating between upright, haploid gametophytes and diploid crustose tetrasporophytes, and in many northerly populations, a diploid asexual life cycle in which female fronds give rise directly to diploid females. Our research examines the spatial genetic structure of mapped individuals of M. stellatus within and among shores from seven sites in France and four sites in Maine using 15 DNA microsatellite markers. DNA was extracted from vegetative tissue of crusts and the stipes of fronds. Signatures of diploid genotypes (i.e., heterozygous at one or more microsatellite loci) indicated that almost all fronds collected in Maine were asexual at most sites. Reduced genetic diversity and high frequency of diploid frond genotypes relative to Eastern Atlantic populations suggest that clonality is the primary mode of reproduction for M. stellatus lineages in the Northwest Atlantic. In France, high levels of genetic structure were observed between sexual (single allele at all loci) and asexual lineages within populations. There was no evidence of isolation by distance among pairwise combinations of individuals within sites (0.05-50 m distances). Our results suggest that short distance dispersal does not hinder gene flow within populations of M. stellatus, but reproductive isolation between sexual and asexual lineages drives their divergence.
Society for Integrative and Comparative Biology, Tampa, FL
Mother knows best: maternal investment causes differences in UV-tolerance of intertidal and subtidal populations of sea urchins
Planktonic larvae of various marine organisms are increasingly being required to respond to a changing physical environment. As Strongylocentrotus purpuratus adults occupy both intertidal and subtidal waters, many questions remain unanswered about how populations residing at different depths prepare their offspring to cope with UVR. For this study, S. purpuratus adults were collected from two intertidal and two subtidal (~15 m) sites from the CA central coast to compare UV tolerance in offspring. UVA (321–400 nm) and UVB (280–320 nm) measurements at the four sites showed UV to be at minimal levels or absent in subtidal sites. Our study found that offspring from intertidal populations experience a less severe developmental delay when exposed to environmentally relevant levels of UVR (using artificial lighting) than offspring from subtidal populations. The mean percent cleavage delay for UV-treated embryos relative to controls was 17.6% for intertidal sites and 23.4% for subtidal sites. Although these embryos are members of the same species and share a common genetic background, they differ in their chances of survival due to differences in the resources provided maternally. This suggests that environmental UV cues or additional environmental cues experienced by intertidal mothers may reduce the negative effects of UV exposure during early development. To explore the role of maternal investment, we are using a proteomic approach to assess differences in protein expression between eggs from intertidal and subtidal populations. This will offer insight into how protein variation provides embryos with a rapid response to stress during early development.
American Geophysical Union, Washington D.C.
Tidal effects on ecosystem exchange of carbon dioxide and methane in restored tidal marshes of San Francisco Bay
Methane (CH4) emission from wetlands, especially freshwater marshes, can be large and therefore offset the carbon mitigation potential of restored wetlands. Despite many studies that have evaluated carbon dynamics in wetlands on the Atlantic and Gulf Coasts, San Francisco Bay, the largest estuary on the west coast, has been understudied. This study investigated how tidal patterns and biogeochemical factors such as salinity, vegetation, and radiation affect CO2, CH4 and energy fluxes in a restored salt marsh. Field data were collected in a 10-year-old restored tidal marsh in Eden Landing Ecological Reserve, a 6,400-acre reserve with diked marsh and restored salt ponds located in the San Francisco Bay. Atmospheric carbon (C) fluxes are being measured using the eddy covariance technique recording continuous eddy fluxes of CO2, CH4, and H2O at half-hourly intervals and calculated using standard flux processing software. Continuous data on soil and water temperature, water table height, turbidity, pH, and greenness index of the canopy are collected within the footprint of the tower. Our analysis focuses on the effect of daily flooded and nonflooded periods on the surface energy balance and ecosystem exchange of CO2 and CH4. Preliminary data shows that Eden Landing marsh is a net sink for both CO2 and CH4, with uptake rates of 124 g C-CO2 m-2 and 14.2 mg C-CH4 m-2 integrated across 129 days (Feb-June 2018). Tidal patterns appear to have a strong impact on ecosystem exchange of Carbon and suggest that marshes with high salinity undergoing regular flooded and unflooded periods can not only be sinks of CO2 but also CH4, which improves their climate mitigation potential.
International Ornithological Congress and Waterbird Society, Vancouver, BC, Canada
Contaminants as ecological tracers: does mercury load reflect foraging habits of a generalist seabird?
Mercury is a commonly monitored contaminant in birds because of its adverse impacts on avifaunal reproduction and survival, but is rarely used as an ecological tracer. Biogeochemical processes can alter mercury bioavailability at multiple spatial scales and habitats, resulting in complex signatures among free-ranging animals. However, when combined with additional foraging data, mercury may be an ideal tracer to link contaminant load to exposure risk among colonies and associated foraging pathways or sites. Here, we pair blood mercury concentrations and GPS tracking data in breeding western gulls (Larus occidentalis, N=156) from five colonies in coastal California and Oregon, USA, to explore the extent to which blood mercury burdens reflect short-term gull foraging spatial patterns. We analyzed tracks using multiple movement analyses, including trip-based metrics and mechanistic movement models to determine foraging locations at land and sea. We then compare individual and colony movement metrics to measured blood mercury values both within and among colonies. Our results connect mercury concentrations with marine and terrestrial foraging in gulls and provide insight into the foraging differences and differences in mercury exposure among breeding western gulls across their range.
Relationship between turbidity and total suspended solids across a salinity gradient in the San Francisco Estuary
Tidal marshes around the San Francisco Estuary face a great threat of loss due to sea-level rise. In order to continue providing their valuable ecosystem services, it is critical that these marshes maintain elevation relative to sea-level rise through belowground root growth and accretion of both inorganic and organic particulates. Transport of suspended sediment from the water column to the marsh surface is crucial to this process and is a target of ongoing study. Measurements of water turbidity can serve as a proxy for suspended sediment, however, it is unknown how well turbidity data approximate the actual concentrations of suspended sediment in different parts of the estuary. To better understand the spatial and temporal dynamics of suspended sediment concentrations, we examine the relationship between water turbidity measured by optical backscatter and the concentrations of suspended sediment measured by filtration. We compare different locations along a salinity gradient within the estuary and pay special attention to the influence of organic matter and particle size on the relationship. Compared with salt marshes, lower salinity brackish marshes typically are enriched in organic matter due to higher plant diversity and productivity. Results of this study increase our understanding of the predictive relationship between turbidity and suspended sediment and should allow for more reliable monitoring of sediment supply and delivery to tidal marshes.
Water flow influences the structure of a coralline alga-associated epifauna assemblage
Crustose coralline algae (CCA) can help induce settlement and provide shelter to a diverse assemblage of invertebrates. Variation in water flow can influence algal morphology, but its relative role in the composition of CCA-associated epifaunal assemblages remains poorly understood. Lithophyllum kotschyanum, a branching species of CCA, is an ideal organism to study this because it is commonly found in the back reefs (high flow) and fringing reefs (low flow) of Mo’orea, French Polynesia. The effect of water flow on the morphology of L. kotschyanum was tested by measuring the branch density, space and penetration depth between branches, and branch diameter of 36 thalli. A total of 1,130 individuals were removed from these and patterns in associated assemblages were examined as a function of morphology and flow. The morphometrics did not significantly differ between the back and fringing reefs. However, there is a significant contrast in the assemblages associated with L. kotschyanum between the two sites, with higher diversity and richness occurring on the back reef. These results suggest that while the rate of water flow did not affect the space available to epifauna, it may be an important driver in the structure of assemblages associated with CCA.
Phycological Society of America and International Society of Protistologists, Vancouver, BC, Canada
Age distributions and morphologic variability in subtidal Ecklonia arborea (southern sea palm) around Isla Natividad, Baja California Sur, Mexico
The perennial stipitate kelp Ecklonia arborea persists along a wide latitudinal range in the Northeastern Pacific and exhibits distinct morphological features including stipe bifurcation and hollowing. Little is known about the persistence of E. arborea within Baja Californian kelp bed communities, and morphology to age relationships are poorly understood. Collections, swath surveys, and field stipe measured and compared in March 2018 to assess age distributions, morphology, and densities of E. arborea around Isla Natividad (IN), Baja California Sur. Thalli were aged by quantifying dark growth rings. Age estimates ranged from 2 to 12 years (mean ± SE = 4.2 ± 2.2) and mean ages varied among sites, as did age distributions. Using stipe length as an age predictor, predictions were validated using thalli collected from a separate site around the island. Predicted age to growth rings comparisons at the validation site had an average deviation of 17.5%. Surveys and stipe lengths were measured at two additional sites within IN's two no-take reserves and were used to predict reserve age distributions. The reserves supported more persistent and denser E. arborea when compared to the other four sites distributed around the island. Thallus size correlated with age, but mean thallus size varied between sites, and relative thallus development with age varied between sites. These results reveal the variable morphology and persistence in E. arborea around IN and support increased persistence and density of E. arborea in reserves, suggesting more stable populations.
Western Society of Naturalists, Tacoma, WA
Do rock crabs drive patterns of California mussel growth and shell deposition on moderately wave-protected rocky shores?
Variation in growth rate and shell deposition play important roles in the ecology of the California mussel (Mytilus californianus), affecting their ability to survive predation and compete for space. Most work on mussel growth and shell deposition has focused on the independent and synergistic effects of food and the abiotic environment (temperature, wave exposure, pH), with relatively little work on the effects of predators. On moderately wave-protected shores of northern California, molluscivorous rock crabs (Romaleon antennarium) are abundant throughout the intertidal zone and could represent a strong selective force on mussel growth and shell deposition. To address this, we combined preference assays and field transplants to determine whether crabs represent an important predation risk to mussels. We found that rock crabs readily prefer mussels over other common molluscan prey in the lab and voraciously consume mussels transplanted low on the shore. We also combined field surveys of mussel morphometrics and crab attack rates on mussel replicas with a common-garden laboratory experiment to examine associations between crab predation risk and mussel growth and shell deposition. We found that mussel size, shell thickness growth rates were all tightly linked with predation risk from crabs; with mussels from high risk locations growing faster and producing thicker shells than mussels from low risk locations. These results suggest that crabs are important but overlooked drivers of growth and shell deposition in California mussels on moderately wave-protected shores.
Benthic Ecology Meeting, St. Johns, Newfoundland, Canada
Interactive effects of light quantity, spectral quality and ocean acidification on a reef-building alga at varying depths in Moorea, French Polynesia
Ocean acidification (OA) negatively affects marine calcifying organisms, and can alter many physiological processes. Crustose coralline algae (CCA), such as Porolithon onkodes, are important structural calcifying components on coral reefs and they grow across a range of depths. This study investigated the interactive effects of light quantity, spectral quality and pCO2 on P. onkodes to determine if CCA are impacted differentially by OA as a function of depth. Specific light filters were utilized to simulate the light regimes that occur at shallow and deep reefs in mesocosm experiments at both ambient and high pCO2 treatments. Results suggest that light availability at depth plays a significant role in rates of calcification and photosynthesis and that these physiological processes are not reduced at elevated levels of pCO2.
AAUS Diving for Science Symposium, Tahoe City, CA
Evaluating the effects of predation risk on prey reproduction in a temperate reef fish
Predators can impact prey fitness through their lethal (e.g., density-mediated) and sublethal (e.g.,trait-mediated) effects. Of the studies that have examined sublethal effects of predators on reproduction in marine fishes, most have been conducted in laboratory settings, but very few have tested these effects in nature. In this study, we aimed to identify how predatory risk cues from temperate reef fishes may influence refuge use and subsequent reproductive output in the bluebanded goby, Lythrypnus dalli. We conducted a field experiment at Santa Catalina Island, California, where we constructed 18 rocky reefs, and populated each with bluebanded gobies and 5 artificial nests to quantify reproductive output during week-long trials. Reefs were covered with one of three caging treatments: (I) large exclusion (low risk), (II) small exclusion (medium risk), and (III) no exclusion (high risk). Goby densities were surveyed visually throughout the trials, and all gobies were recollected at the end of the experiment. In the high-risk treatment, gobies produced 33% fewer eggs, and were seen 20% less frequently than those in the low and medium-risk treatments. There were no differences among treatments in the proportion of gobies recollected, suggesting that the increased refuge use from sublethal predator effects led to the decreases in reproductive output. These results imply that sublethal predator effects on reproductive output may be substantial in nature. Furthermore, this study will help us understand how practices affecting predator abundance (e.g., overharvesting or protecting) may alter reproductive output and fitness of prey in the marine environment.
National Shellfisheries Association Triennial, New Orleans, LA
Population trends and abundance of Pismo clams, Tivela stultorum, in California
Pismo clams (Tivela stultorum), an iconic fishery species in California, once supported a thriving commercial and recreational fishery. Overharvest led to the closure of the commercial fishery in 1947, while recreational harvest is still permitted today. However, Pismo clam populations have continued to decline throughout the state of California despite numerous management actions by the state. We designed a study to examine the relationship between Pismo clam abundance and a variety of abiotic and biotic factors. This study will improve our understanding of this socioeconomically important species and potentially improve Pismo clam management within California. We quantified Pismo clam presence and abundance along their entire range in California from Monterey, CA to the US-Mexico border. Additionally, we evaluated biotic and abiotic factors, such as predator presence, human population density, beach slope, sediment grain size, and wave intensity, to determine potential drivers of clam presence and abundance. Our results suggest that predators and human population density are not strongly correlated with Pismo clam presence and abundance. Abiotic factors were generally more strongly correlated with Pismo clam presence. It is likely that several of these factors interact to drive clam abundance. Future work will examine these biotic-anthropogenic-habitat interactions to help us better understand the ecology and potential recovery of Pismo clams in California.
Ecological consequences of Sea Star Wasting Disease: non-consumptive effects from Pisaster ochraceus
Since the onset of Sea Star Wasting Disease (SSWD), variation in disease-related mortality and population recovery along California’s North Coast has caused an abundance gradient of the predatory sea star Pisaster ochraceus, suggesting site-specific community-level consequences. To date, research on SSWD community-level impacts has focused on consumptive effects (CEs). However, Pisaster also have non-consumptive effects (NCEs) by modifying prey behavior, which can have cascading effects on other community members. Here, we combined laboratory and field experiments to examine Pisaster NCEs on Tegula funebralis grazing, and cascading effects on macroalgae. Cage-exclusion experiments across the Pisaster abundance gradient indicated that Tegula grazing intensity decreased with increasing Pisaster density. Further, experimental Pisaster additions caused large reductions in Tegula grazing in areas with low background Pisaster density. Consistent with our field results, a laboratory experiment examining Tegula grazing and avoidance behavior under field-relevant Pisaster cue levels indicated decreases in grazing, and increases in avoidance behavior, with increasing cue density. Our results indicate that Pisaster NCEs on Tegula are density-dependent, and Pisaster density reductions reduce positive indirect effects on macroalgae, potentially affecting community structure. As Pisaster abundance begins to recover at some sites, our results highlight the importance of considering non-consumptive pathways when assessing the community-level impact of SSWD.
Testing the effects of elevated temperature on gumboot chitons with the use of biomimetic models and laboratory experiments
Global climate change is increasing both average and extreme air and ocean temperatures, both of which can have negative consequences for intertidal organisms; particularly mobile grazers. Gumboot chitons (Cryptochiton stelleri) are a large, understudied grazer on rocky reefs in the north Pacific. They are thought to be thermally sensitive and some populations have been shown to be immobilized by high air and water temperatures (20°C and 18°C, respectively). To quantify the frequency of exposure to these temperatures in the field, we constructed biomimetic models (aka “roboboots”), which matched live gumboot temperatures within 1°C, and deployed them in the intertidal zone at four Northern California sites in summer 2018. Currently, gumboots are infrequently exposed to these extreme temperatures, but do routinely experience air and water temperatures up to 18°C and 15°C, respectively. Because high temperatures could increase gumboot metabolism and intensify grazing, or could cause stress and decrease grazing, we measured the grazing rates of gumboots exposed to increasing air temperatures (16, 18, 20°C) during simulated low tides and increasing water temperatures (13, 15, 18°C). Low tides, regardless of air temperature, rendered gumboots unable to graze during subsequent emersion, whereas grazing rates increased in seawater from 13°C to 15°C, but decreased at 18°C. Gumboot’s exposure to elevated temperatures will increase with predicted climate change, which we hypothesize will negatively affect their populations and consequently, their grazing impact on macroalgal communities.
Coseismic uplift and coastal emergence along the Southern Hikurangi Margin, North Island, New Zealand
The Hikurangi subduction margin along North Island, New Zealand accommodates oblique convergence of the Pacific Plate beneath the Australian plate at 45 mm/yr. Emergent marine terraces and paleo-shorelines record tectonic uplift over two time scales: 1) short-term episodic uplift events during the Holocene (0-10 ky), and 2) long-term net deformation during the Pleistocene (10-500 ky). Field investigations of the NSF SHIRE Project (Seismogenesis at Hikurangi Integrated Research Experiment) are revealing new insights on regional paleoseismology and morphotectonics. Along the southern Wairarapa segment, a narrow coastal lowland preserves uplifted Holocene terraces and beach ridges that record 4-7 prehistoric earthquakes. LiDAR mapping and terrace correlation from Te Kaukau Point to Flat Point link prior sites where 14C ages constrain paleo-earthquake. From Flat Point to Riversdale, four Pleistocene marine terraces record long-term uplift and margin-parallel folding. OSL ages from terrace cover beds at 5 sites constrain vertical deformation rates. Along the southern Hawke’s Bay segment, 1-3 uplifted Holocene terraces occur between Black Point and Cape Kidnappers. Mapping, field surveying, and 14C dating of shell samples at 14 sites constrain the timing and magnitude of coseismic uplift events. Mapping and OSL dating of several higher Pleistocene terraces characterize long-term uplift and deformation along the Kidnappers anticline. Uplifted Holocene paleo-shorelines record single coseismic uplift events, while Pleistocene terraces characterize net deformation patterns. Differentiating between very large margin-wide megathrust ruptures (M8.0-9.0+) and smaller, more localized, upper-plate thrust events (M7.0-8.0) is crucial as, both earthquake types pose a significant seismic and tsunami hazard for New Zealand residents.
World Aquaculture Society Conference, New Orleans, LA
Evaluation of waste consumption by the polychaete Alitta brandti in a recirculating integrated multi-trophic aquaculture system
Integrated aquaculture methods are known to enhance the sustainability of many fishes and their production. The wastes and byproducts from the culture of one species can be managed to contribute to the requirements of another. One of the biggest challenges in marine recirculating aquaculture systems is the handling of wastewater. Finding organisms that might feed on these organic wastes such as deposit-feeding polychaete worms could be beneficial for waste bioremediation. Some of these worms are used as a highly prized fish bait and they could be used as meal replacement in aquaculture feeds. The goal of this pilot study was to evaluate the nutrient bioremediation and growth responses of the nereid polychaete (Alitta brandti) by feeding them waste from a recirculating land-based integrated multi-trophic aquaculture system.
Western Society of Naturalists, Tacoma, WA
Trends of marine debris accumulation on California's Channel Islands
The persistence of plastics and other marine debris in coastal and marine ecosystems has become an issue of global concern. In the Santa Barbara Channel off the coast of Southern California, marine debris accumulates on mainland and offshore island coastlines from multiple sources such as commercial fisheries, storm water discharge, beachgoers, and vessels. The proximity of the Channel Islands to the nearby highly populated mainland coast coupled with unique oceanographic conditions lead to variable types and abundances of marine debris on the Channel Islands. Here, we present results on the first study to quantify and compare the types and amounts of marine debris on Channel Island shorelines. To document the extent of marine debris in this region we collected seasonal data from fall 2016 to fall 2018 on the types and density of shoreline marine debris from seven beaches on Santa Rosa and Santa Cruz Islands. Debris from all surveyed beaches was cataloged and weighed to compare seasonal variation in abundance and composition. The majority of island debris was made of plastic, lost fishing gear also comprised a significant proportion of shoreline debris. Santa Rosa Island beaches had the highest densities of marine debris. In addition to documenting marine debris trends, we developed best practices for removing marine debris from ecologically and culturally sensitive island beaches where logistics are challenging. Understanding marine debris trends and accumulation rates will ultimately improve the efficacy of mitigation and marine debris removal efforts in this region.
International Cassiopea Workshop, Key Largo, FL
Investigating the potential for evolutionary rescue in a model cnidarian-dinoflagellate symbiosis
Identity-driven non-consumptive effects on the rocky shore: ‘The only thing you have to fear...is Pisaster itself’
On the west coast, a recent outbreak of sea star wasting disease (SSWD) has led to local decreases in the abundance of a major predator, the ochre sea star (Pisaster ochraceus). To better understand the ecological consequences of Pisaster declines through non-consumptive effects (NCEs) on prey, we asked whether Pisaster and other predators, namely crabs and octopuses, could regulate the grazing and growth of an abundant herbivorous snail (Tegula funebralis) on rocky shores in northern California. In laboratory experiments, Tegula exposed to Pisaster risk cues increased their avoidance behavior, decreased grazing, and grew less, relative to control cues. In contrast, Tegula exposed to cues from either crabs or octopus exhibited little to no avoidance behavior, and grazed and grew to the same extent as control snails. In treatments where predator chemical cues were combined, Tegula exhibited avoidance behavior only when Pisaster cues were present. In support of our lab results, field surveys revealed strong correlations between Tegula vertical distribution (a result of anti-predator behavior) and Pisaster abundance, but not with the abundance of crabs, octopus, or other sea stars. Together, our results provide evidence that Pisaster presence matters more than a diverse predator assemblage for initiating NCEs on Tegula grazing, growth, and vertical distribution. Thus, areas heavily impacted by SSWD could see shifts in Tegula vertical distribution and an increase in herbivorous grazing due to decreases in abundance of this potential ‘keystone intimidator’.
Evaluating the capacity of fleshy macroalgae to buffer seawater from ocean acidification
Climate change may induce phase shifts on coral reefs from calcifier dominance to fleshy macroalgal dominance. An increase in atmospheric CO2 causes ocean acidification (OA), reducing calcification in reef builders, such as crustose coralline algae (CCA). Photosynthesis by epiphytic algal turfs on CCA may mitigate OA locally through carbon uptake, resulting in a pH increase on localized regions of the CCA surface. The combined effects of OA and algal turfs were quantified in a mesocosm study conducted in Mo’orea, French Polynesia. The common CCA species, Lithophyllum kotschyanum, was used to test whether epiphytic turfs can alter pH within the diffusive boundary layer (DBL) of host CCA, and consequently alter CCA calcification. In a factorial experiment, samples were placed in flow through tanks in which algal turfs were present or absent, and pCO2 was ambient or elevated. Results indicated no effect of elevated pCO2 on CCA calcification and a negative effect of turf presence, despite a higher pH in the presence of turf during light incubations. This indicates that any benefit of higher daytime pH within the DBL of L. kotschyanum was far outweighed by the negative effects, such as shading, nighttime anoxia and low pH, or microbial activity.
Life history traits influencing the recovery of rocky intertidal macroalgae
Complex life cycles are hypothesized to act as bet-hedging strategies that can be adaptive in variable environments, like those of temperate rocky shores. Ecological strategies, such as bet-hedging, are manifest through traits including morphology, reproductive mode and ploidy (through its effect on genetic diversity). Many macroalgae inhabiting littoral zones possess complex life cycles that include asexual stages as well as sexual generations that differ in morphology and ploidy. We studied populations of Mastocarpus along the Central Coast of California to test three hypotheses about the elasticity and resilience to disturbance of the different morphologies, reproductive modes and generations: (1) upright frond stages would colonize more rapidly and be more abundant than crustose sporophytes, (2) frond domination would result from more rapid colonization by asexual female fronds than by sexual stages, and (3) sexual and asexual diploid stages would colonize more rapidly than sexual haploid stages. In our plots, we found settlement of crustose individuals prior to upright individuals, initial crustose coverage eventually matched by frond cover, and no relationship between diploid uprights and plot recovery. These results suggest ploidy plays a lesser role in recovery, and reproductive mode and morphological traits providing resistance to disturbance grant the highest recovery success.
Impact of and recovery from parrotfish predation on threatened Orbicella annularis corals in a Caribbean marine reserve
Herbivorous parrotfishes (Scaridae) indirectly benefit corals by grazing algae, thereby reducing coral-algae competition. Increasing parrotfish abundance to promote coral resilience is a major priority for many managers; however, heavy parrotfish fishing pressure in parts of the Caribbean remains a challenge. While parrotfishes are primarily herbivores, certain species occasionally feed on corals. Research is needed on the tradeoff between negative impacts of parrotfish corallivory and positive impacts of herbivory to estimate their net impact on corals. Parrotfishes prey upon many coral species, but preferentially target threatened Orbicella annularis. There is increasing concern that parrotfish predation may contribute to substantial long-term declines in O. annularis. We studied how intensity of O. annularis corallivory varies in response to site-level differences in parrotfish biomass, and coral and algal abundance on St. Croix, USVI. We compared five sites on the Northern coast, where fishing pressure is high, to three sites on Buck Island, a well-enforced marine reserve. Additionally, we monitored bite scar healing over time to quantify the frequency and rate of healing in response to scar size and shape and coral colony size. These data will allow us to model the projected long-term loss versus healing of O. annularis tissue from a standing stock of bite scars. This research improves our understanding of how differences in parrotfish biomass and benthic community assemblage alter the impact of parrotfish predation on a threatened coral species.
International Wildlife Reintroduction Conference, Chicago, IL
Using spatial risk assessments to inform reintroduction of southern sea otters into a highly urbanized estuary
Despite decades of federal and state protection, the southern sea otter – today found only in California – continues to experience sluggish population growth and has reclaimed only a fraction of its historic range. Managers of this threatened species have identified the growing need to facilitate range expansion via reintroductions in order to address the challenges facing southern sea otter recover. San Francisco Bay has been identified as a candidate reintroduction site, but despite having historic presence in the Bay, sea otters have been largely absent from this ecosystem for over a century and it is unknown whether they could live in this highly urbanized estuary today. Sea otters attempting to resettle San Francisco Bay will contend with threats from a diverse array of human activities in the Bay. To address this knowledge gap, we used spatially-explicit risk assessment framework to assess the quality and availability of sea otter habitat given exposure to multiple anthropogenic stressors. By incorporating risk into predictive habitat suitability modeling we are able to provide critical information to managers about the potential threats sea otters will face that could undermine their attempts to reoccupy their historic home range.
The effects of an invasive alga, Sargassum horneri, on the foraging of temperate rocky reef fishes
Invasive species can alter habitats dramatically when they thrive in foreign conditions. Sargassum horneri is an invasive alga from the Northwestern Pacific that is flourishing in the waters off Santa Catalina Island, California. The effects of this alga’s presence on higher trophic levels, such as fish, is unknown. This study quantified the foraging rates of three common reef fishes (Halichoeres semicinctus, Hypsypops rubicundus, and Semicossyphus pulcher) that prey upon small epifauna associated with understory algae, including the invasive S. horneri. Foraging observations were made by scuba divers at six sites along the leeward side of Catalina Island. At all six sites, fishes foraged at higher rates among the native, S. palmeri, than the invasive S. horneri. Even at sites with low algal diversity, fishes still foraged at lower rates among S. horneri. Our results suggest that the invasive S. horneri negatively impacts the foraging of native fishes, perhaps because of a low abundance of epifauna inhabiting this alga. These results suggest that the increasing prevalence of S. horneri on rocky reefs in Southern California and Baja California may impact higher trophic levels in invaded ecosystems.
The effects of ocean acidification and temperature on the growth and photosynthetic performance of tropical macroalgae
Predictions regarding ocean acidification (OA) and temperature have most commonly focused on the effects of these environmental stressors on marine calcifying organisms, specifically those that play a critical role in the formation of reefs (e.g., corals and crustose coralline algae). However, the potential effects of OA and temperature on the physiological mechanisms by which fleshy macroalgae utilize carbon dioxide (CO2) or bicarbonate (HCO3-) from the surrounding seawater for photosynthesis or which species may benefit under future climate change conditions are less well known. It is predicted that increased CO2 and temperature due to climate change might have positive effects on the growth and photosynthesis of fleshy macroalgae. This study examined the growth and photosynthetic rates of two tropical fleshy macroalgae (Turbinaria ornata and Sargassum pacificum) under ambient and elevated pCO2 and temperature in a factorial design. The contribution of the enzyme carbonic anhydrase (CA) to the uptake of inorganic carbon for use in the photosynthetic process was also measured by using inhibitors of both external and internal CA. Results highlight the importance of the use of HCO3- compared to CO2 as an inorganic carbon source to support maximal rates of photosynthesis and the significance of species-specific CO2 concentrating mechanisms.
Western Society of Naturalists, Tacoma, WA
Fish pee: a hidden source of limiting nutrients in California kelp forests
Nutrient cycling is an essential ecosystem process. In marine systems, organisms supply limiting nutrients to the ecosystem via excretion of metabolic waste products. Surprisingly, relatively little is known about the magnitude and variability of this recycling regime at the species- or community level, especially in temperate kelp forests. To address these questions, we investigated the supply of nutrients excreted by the dominant members of the fish community in California. Rapid field incubations were conducted to measure the amount of dissolved ammonium (NH4+) released per individual (n=550) as a function of fish size across 40 common species that cumulatively represent 90% of the fish biomass. Ammonium excretion rates were combined with fish density and size structure from visual SCUBA surveys to calculate the total nutrients supplied by fishes at the population and community levels. Our preliminary results indicate that fishes contribute a substantial amount of nitrogen to the ecosystem (5- 10 mmol NH4+ m-2 day-1), potentially surpassing the flux of nitrate delivered by upwelling and other oceanographic processes. These rates are consistent with those reported for tropical reefs but are among the first in temperate systems, indicating that fish-derived nutrients may be an underappreciated process that influences kelp forest productivity, especially during low nutrient conditions (i.e. El Niño). Further research is aimed at understanding fish-derived phosphorous supply and potential anthropogenic effects (i.e. fishing) on nutrient cycling in kelp forests.
Society for the Advancement of Chicanos/Hispanics and Native Americans in Science, Salt Lake City, UT
Effects of low tide exposure on photosynthetic potential of the intertidal seaweed Silvetia compressa
Organisms in the rocky intertidal zone are exposed to marine and terrestrial stressors daily. Conditions during low-tide emersion can be particularly stressful for sessile organisms such as the seaweed Silvetia compressa. We hypothesized that exposure to high light or high temperature during emersion would decrease photosynthetic potential and inhibit recovery of S. compressa, and that these factors would have strong effects when combined, especially with repeated emersion. We conducted a two-day manipulative experiment with one ‘no low tide’ and four ‘experimental low tide’ treatments with combinations of two levels of temperature and light (high/low), maintaining fronds in high-tide conditions between exposures (n=10 S. compressa individuals). We measured maximum quantum yield (MQY) as an indicator of photosynthetic potential before and after each low tide and again following the final recovery period. Fronds exposed to high light showed greater declines in MQY during emersion than fronds exposed to low light. After one high tide recovery period, at the start of the second low tide, MQY in the ‘high light, high temperature low tide’ treatment was, on average, 77% of original levels, while MQY in all other treatments exceeded 85% of original levels. This negative effect was magnified after two successive low tides, suggesting that high temperature exacerbates the strong negative effects of high light levels on S. compressa, potentially by inhibiting repair pathways. Understanding the impact of low-tide exposure on ecologically significant species such as S. compressa is essential to enable us to predict the effect of climate change on intertidal systems.
Society for the Advancemnet of Chicanos/Hispanics and Native Americans in Science, Salt Lake City, UT
Outcompeted or outbred? Localized extirpation of a native mussel via interspecific hybridization with a highly invasive congener
In southern California estuaries, non-native bay mussels, Mytilus galloprovincialis, are widely presumed to have replaced native bay mussels, Mytilus trossulus, but the regional extent and underlying processes influencing species replacement are poorly understand. Local aquaculture production of M. galloprovincialis provides the potential to enhance non-native spread and establishment, which may greatly influence native replacement and/or hybridization between the two species. Mytilus hybrid zones, whereby native and non-native species co-occur and interbreed are known from central California north to Vancouver Island, but are not reported in southern California. Using molecular genetics, our objectives are to characterize the species composition of mussel communities across salinity and elevation gradients in Orange County, California. Individual mussel samples were collected in Newport Bay (NPB), at three sites of varying salinity. We use species-specific genetic markers (Glu-5 and ITS) to identify pure-type individuals of both species, and hybrid individuals. Preliminary results to date show 100% of sampled mussels in NPB are M. galloprovincialis, suggesting complete replacement of native mussels with non-natives in NPB throughout the environmental gradients. Further sampling is ongoing, and this work will likely provide a better understanding of the processes responsible for native bay mussel extirpation, with possible implications for enhanced native mussel restoration.
Society for the Advancement of Chicanos/Hispanics and Native Americans in Science, Salt Lake City, UT
U.S. west coast estuaries support diverse communities that can be negatively impacted by changes in water quality. Atmospheric river (AR) events, long, narrow corridors of water vapor delivering heavy precipitation, can reduce the water quality in estuaries to levels lethal to oysters. For example, native Ostrea lurida densities declined significantly in San Francisco Bay following an extreme AR event that decreased salinities for a lethal duration (< 6 ppt for > 8 d). We focused our study on southern Californian estuaries that support native oysters, O. lurida, and non-native oysters, Crassostrea gigas. We hypothesized that AR events would produce extreme drops in salinity for lethal durations, as in San Francisco Bay, and O. lurida would show greater density declines than C. gigas. We measured density of both species in January and May 2017 at two sites each within Newport Bay (NB) and San Diego Bay (SD). Four AR events impacted NB and three impacted SD between December 2016 and May 2017. Salinity and pH dropped below tolerance levels for non-lethal durations in SD. Crassostrea gigas density declined significantly at three of four sites; however O. lurida showed no density change. Native O. lurida may be more acclimatized to local AR events than recently introduced C. gigas, or C. gigas declines may be due to another unknown factor. San Francisco Bay may be more susceptible to AR impacts on oysters by experiencing more extreme ARs and having a larger watershed; both can lead to more significant impacts on estuarine water quality.
Reproductive development of a deep-sea dragonfish (Stomias atriventer)
The black-belly dragonfish (Stomias atriventer) is a deep-sea species of Stomiiforme found in the eastern Pacific. Aspects of the black-belly dragonfish life history have been described including larval development, general morphology, biomechanics, and general behavior. However, little is known about the reproductive biology of this uncommonly observed deep sea fish. Our study explores the reproductive development of the black-belly dragonfish, specifically ovarian and testicular development. Dragonfish were collected via mid-water trawls onboard the R/V Yellowfin in southern California. We also examined museum specimens. The ovaries and testes were dissected, preserved in Bouin’s fixative, and histologically processed using paraffin wax. We had determined the diameter of ovarian follicles of various stages of development: primary ovarian follicles were 45.4 ± 19.1 µm, secondary ovarian follicles were 88.7 ± 21.4 µm, and tertiary ovarian follicles were 223.1 ± 27.9 µm. The testis contained spermatocytes that were 3.63 ± 0.18 µm, spermatids were 2.00 ± 0.16 µm, and mature sperm were 2.30 ± 0.53 µm in diameter. Our work will continue this summer with additional trawls, and we hope to determine the timing of reproduction in the black-belly dragonfish. Our research findings will increase our understanding of the seasonal development of deep sea fishes, an important trophic link to the surface waters of the ocean.
Assessing degree of resistance of antibiotic resistant coliforms isolated during dry and wet weather at beaches with differing wave action
Invasive bryzoan -- Watersipora research
Immune responses in breeding adult male elephant seals
Repeated epipodial tissue sampling to correlate gene expression and heat stress survival in the intertidal marine snail Chlorostoma fune
Investigation of blood cell populations in the development and regeneration of Botrylloides vidaceus
Feeding preferences for Littorina scutulata and Chlorostoma funebralis and the effects of low tide exposure on rockweed (Silvetia compressa)
A comparison of swimming performance between the salt marsh harvest mouse and coexisting rodents in the Suisun Marsh, California
Repeated tissue sampling to correlate gene expression and heat stress survival in the intertidal marine snail Chlorostoma funebralis
Molecular phylogenetic and morphological analyses reveal two new species of sea slugs in the genus Placida (Heterobranchia: Sacoglossa), including one from California
A cross-species comparison of the lateral pallium in Muraenidae and Anguillae as an indication of evolution of spatial cognition
Gradients in metabolic performance across the intertidal zone: a comparative analysis of mussels and barnacles