Poster Session: Abstracts & Awards
The MBNMS presents awards for outstanding research posters presented at the MBNMS Sanctuary Currents Symposium. The judges determine the specific kinds of awards to present each year based on the posters presented at the Symposium.
Poster Session Abstracts
Anima, Roberto J., Andrew J. Stevenson, and Stephen L. Eittreim
U.S. Geological Survey, Marine and Coastal Studies Group
PALEO-DRAINAGE PATTERNS ACROSS THE INNER CONTINENTAL SHELF, MONTEREY BAY CALIFORNIA
High resolution seismic reflection profiles across the continental shelf in northern Monterey Bay reveal several buried linear depressions in the planar, wave cut bedrock surface suggesting paleo-drainage system formed during past sea-level lowstands. Offshore seismic profiling normal to onshore river valleys verifies the coincidence of many of these linear depressions with subaerial drainage systems. Some of these buried channel features can be traced across the shelf to offshore submarine canyons. Profiles between the mouth of Soquel Creek and the head of Soquel Submarine Canyon reveal a meandering paleo-channel that trends toward the head of the canyon. A similar depression offshore of the San Lorenzo River Valley suggests it also continues seaward as a branching paleo-drainage system that was incised across the continental shelf during the last sea-level low stand.
Bonnell, Michael L. (1), and R. Glenn Ford (2)
1. Institute of Marine Sciences, University of California Santa Cruz
2. Ecological Consulting, Inc., Portland, Oregon
MERGING GIS AND GPS CAPABILITIES FOR RESEARCH AND MANAGEMENT OF SANCTUARY RESOURCES
Geographical Information Systems (GIS) and Global Positioning Systems (GPS) are now used routinely to interrelate research data with co-registered basemaps. On aerial surveys of marine birds and mammals, GPS directly inputs time and latitude/longitude to an on-board GIS mapping system. The GIS shows aircraft position relative to shoreline, bathymetry, location of bird colonies, pinniped haulout sites, and other relevant information. Since June 1994, 37 surveys have been flown including more than 18,000 km (10,000 nmi) of transects in Sanctuary waters. These surveys have resulted in an enormous database for describing the density-distribution of marine birds and mammals. Concurrently, a comprehensive database has been produced for the Gulf of the Farallones NMS that includes all available biological, oceanographic, shoreline sensitivity, and other information that can be combined and analyzed on a fast PC desktop or laptop computer. The user may window any portion of the coast and select from menus of more than 50 themes. Capabilities include query of database files for specific information (e.g., number of each species at a particular bird colony), edit and update, enumeration and scaling, and lineal or areal measurement; maps can be composed on-screen and printed in color.
Bunzel, Rita C., Shawn L. Carner, Cynthia Klock, Giacomo Bernardi, and John Pearse
University of California Santa Cruz
COMPARISON OF SPECIES DIVERSITY IN THE KELP FOREST OF HOPKINS MARINE LIFE REFUGE: 1971-72 AND 1995
Most species of algae and invertebrates in the Hopkins Marine Life Refuge were identified by students in the first two kelp forest ecology classes taught there in summer 1971 and fall 1972. Students in the fall 1995 Kelp Forest Ecology class at UC Santa Cruz resurveyed the same area for comparison with the 1971-72 lists. Preliminary analyses revealed a number of notable differences. In particular, several species that occurred mainly in southern California kelp forests and were rare or absent in the Hopkins Marine Life Refuge in 1971-72, are now conspicuous and common: the whelk Kelletia kelletii, the tube snail Serpulorbis squamigerous, the crabs Paraxanthias taylori and Heterocrypta occidentalis, the bryozoans Diaperoecia californica and Pherusella brevituba. Other species that were conspicuous and common in 1971-72, including those with more northerly ranges, were scarce or rare in 1995. Further analyses will be carried out to determine if these differences might be related to climate or other changes over the past 23 years.
Cacchione, David A. and Florence L. Wong
Western Marine and Coastal Geology, U.S. Geological Survey
INTERNAL WAVES ON THE CENTRAL CALIFORNIA CONTINENTAL SLOPE AND UPPER RISE
A linear inviscid model of normally incident, shoaling internal waves is applied to the region of the continental slope and upper continental rise off Monterey and San Francisco, CA, between 36o and 38o N. The model results, which describe the reflection properties of the internal waves, are illustrated in graphical format to show those sections of the seafloor where the internal wave energy propagates (1) upslope, (2) back into the ocean interior, or (3) along the slope. In the last case, studies from laboratory experiments and numerical modeling indicate that the internal wave motion is intensified along the slope within a thin oscillating bottom boundary layer. At or very near coincidence between the slope of the incoming boundary layer becomes unstable and internal vortices and breaking occur. Energy dissipation along the slope is substantially increased under this condition, leading to enhanced mixing along the bottom. The internal semi-diurnal (M2) tide is critical (case 3 above) along the lower continental slope (from about 2 to 3 km), and in isolated sections along the axis of Monterey Submarine Canyon. Bathymetry from Multi-Beam sonar surveys was used to compute gradients of bottom slope throughout this rugged and highly irregular section of seafloor. Historical density profiles were used to compute the stability frequency of the stratified ocean interior from 300 m to about 3000 m.
Institute of Marine Science, University of California Santa Cruz
THE EFFECT OF LAND-USE PRACTICES ON BENTHIC PROCESSES IN A WEST COAST ESTUARY, ELKHORN SLOUGH, CA
Elkhorn Slough, CA is an estuary typical of the California central coast. Land-use in the watershed includes intensive agricultural production (mainly strawberries), cattle grazing and protected areas in the National Estuarine Research Reserve System. Ammonium regeneration, nitrification and benthic fluxes were measured in sediments adjacent to either cultivated, grazed or natural areas. Measurements were made 3 times throughout the year: in January during the winter rainy season when temperatures are low (10oC) and rainfall is highest, in May near the end of the rainy season when temperatures have increased to about 15oC, and in September at the end of the dry season when temperatures are maximal (20oC). Although rates of benthic processes were seasonally variable, there were some consistent differences based on adjacent land-use. Sediments adjacent to the cultivated areas were very organic rich (20-30% organic matter LOI) with significantly higher sediment oxygen consumption than either the grazed or natural sites. Despite shallow water depths (< 1m), overlying water at some of these cultivated sites periodically goes hypoxic and anoxic leading to a significant reduction in nitrification rates (from either sediment slurries or intact cores) compared to the natural or grazed sites.
University of California Santa Cruz
AN EAGER POOL OF YOUNG SCIENTISTS, THE UNIVERSITY OF CALIFORNIA SCIENTIFIC DIVING PROGRAM
Each year approximately 30 undergraduate scientists are trained as scientific divers at UCSC. They are trained according to the American Academy of Underwater Scientists Standards. As part of their scientific training they will assist researchers collect data for their long-term projects. Examples of researchers the classes have worked with include, Nicole Crane (Hopkins Marine Lab), Molly Cummings (UCSB), Jim Estes (UCSC/NBS), Jerry Loomis (Pt. Lobos State Park), and Laura Rogers- Bennett (UCSC/BML). They are also available to help other researchers when a large number of divers are needed for a specific study. Up to twenty-five of these scientific divers will take the Kelp Forest Ecology course that is offered each Fall Quarter at UCSC. Many of these students will go on to conduct their own senior thesis research.
Chang, Marshall C-D, Peter J. Macht, Shanette M. Rillorta, Jenny A. White, Giacomo Bernardi, and John Pearse
Department of Biology, University of California Santa Cruz
COMPARISON OF FISH ABUNDANCE IN THE KELP FOREST OF HOPKINS MARINE LIFE REFUGE: 1971 AND 1995
The fish population at Hopkins Marine Life Refuge has experienced considerable change in the last 25 years. Both decreases and increases in abundance were observed in different species. Observations were made by the Fall 1995 Kelp Forest Ecology Class at UC Santa Cruz and compared to a previous survey done by a similar class taught by Hopkins Marine Station and by personnel of the California Department of Fish and Game in 1971. Among the most impacted species, Blue rockfish, Kelp bass and Pile surfperch showed the most dramatic decreases, while Black and Yellow rockfish and Kelp rockfish showed a notable increase. Further analyses will be carried out to determine if these differences might be related to climate or other changes (such as overfishing and the recent establishment of a Harbor Seal population) over the past 25 years.
Collins, C. A., R. G. Paquette, and S. R. Ramp
Department of Oceanography, Naval Postgraduate School, Monterey
ANNUAL VARIABILITY OF OCEAN CURRENTS AT 350M-DEPTH OVER THE CONTINENTAL SLOPE OFF POINT SUR, CALIFORNIA
Currents were measured at 350m from May 1989 through February 1995 over the 800m isobath off Point Sur, California. Mean flows were directed toward 334 degrees at 7.6 cm/s. The pattern of monthly mean flow reveals a distinct annual pattern: the spring transition in mid-April is marked by minimum temperatures and a tripling of undercurrent speeds and is preceded by onshore flow. The strong poleward flow persists for two months and is accompanied by steady warming. When the flow decelerates, temperatures remain high until mid-December when cooling begins.
Costa, Daniel P. (1), Dawn Goley (1), Danielle Waples (1), Don Croll (1), Burney Le Boeuf (1), John Calambokidus (2), and James Harvey(3)
1. University of California Santa Cruz
2.Cascadia Research Collective
3. Moss Landing Marine Laboratory
MARINE MAMMAL RESEARCH PROGRAM FOR THE PIONEER SEAMOUNT ATOC EXPERIMENT
This presentation will outline the research program currently in place to study the potential effect of the California ATOC experiment on marine mammals. We are currently using aerial surveys to get an initial view of the distribution and abundance of animals in the vicinity of the Pioneer Seamount period prior to any ATOC transmissions, and we have been deploying satellite tags and time depth recorded on northern elephant seals to determine if they pass by the Pioneer Seamount. The present plan calls for the ATOC sound source to be operational during November 1995. After an initial test period, when the source will be operated at a low level (185dB re 1m Pa) ATOC transmissions would be manipulated to assess effects on marine mammals using a transmission protocol of 4 days on, 7 days off. Any changes in the animals distribution, abundance and general behavior would be measured by comparison between these two periods. This experimental pattern would be replicated to provide statistical power. We will use aerial surveys to assess distribution and abundance, shipboard observations to assess behavior, a towed array to assess acoustic behavior, photo-identification to examine long-term movements and stock identity, satellite tags and time depth recorders placed on migrating and translocated elephant seals to monitor any changes in behavior and movements.
Danner, Eric, Veronica Franklin, Lani Watson, and John Pearse
Department of Biology, University of California Santa Cruz
LONG-TERM TRENDS IN ROCKY INTERTIDAL ASSEMBLAGES OF CENTRAL CALIFORNIA
In 1971-73 students of the University of California, Santa Cruz, surveyed the distribution and abundance of algae and invertebrates at over a dozen rocky intertidal areas along the coast of Monterey, Santa Cruz, and San Mateo counties. These areas have been resurveyed intermittantly by students since that time, revealing what appears to be consistent between area differences and within area stability, despite droughts, floods, and earthquakes during the intervening years. The most extensively studied area, at Soquel Point, was the site of Santa Cruz County's domestic sewer outfall until it was discontinued in 1976. Annual monitoring showed that many species returned to the area within a few years after the discharge ceased. However, the two visually dominant species, the coralline alga Corallina vancouveriensis characteristic of sewage impacted areas, and the surfgrass Phyllospadix spp. found in clean, unpolluted areas, still show the impact of the discharge, 20 years after termination. In 1996-97 we plan to have students intensively resurvey all the areas surveyed in 1971-73 to determine more precisely the stability of these biotically rich and diverse assemblages. Supported in part by funds from the Association of Monterey Bay Area Governments (AMBAG) and California Sea Grant College.
Dingler, John R. and Thomas E. Reiss
U.S. Geological Survey
CHANGES IN SELECTED MONTEREY BAY BEACHES BETWEEN THE 1982-83 EL NIN0 AND 1995
A beach profiling program in Monterey Bay began in February 1983, during the height of severe El Niño generated storms. Initially, nine beaches were surveyed, and later four beaches were added to fill gaps in the coverage. The 13 beaches extend from New Brighton State Beach in the north to Monterey State Beach, adjacent to the east Monterey breakwater, in the south. Surveys were conducted approximately monthly in 1983 and biannually through 1995. The beaches that were first surveyed during the severe storms spawned by the 1982-3 El Niño were extremely eroded. All of those beaches have rebuilt, but whether they returned to their pre-El Niño positions is unknown because there are no pre-storm surveys for comparison. Since the 1982-3 storms, lower energy conditions have prevailed, and a series of closely spaced storms has not occurred. This climate allowed the beaches initially to build seaward and, subsequent to 1985, all the beaches have maintained a relatively constant average location while undergoing fluctuations in response to changes in wave climate. The beaches could well maintain those average locations until the next episode of storms with the intensity of the 1982-83 storms.
Eittreim , Stephen L. and Andrew J. Stevenson
U.S. Geological Survey
SEAFLOOR ACOUSTIC MAP OF THE SOUTHERN MONTEREY BAY SHELF
The southern Monterey Bay continental shelf was recently swath-mapped with the Simrad EM-1000 system. This system produces 96-channel bathymetric and acoustic backscatter information along swath widths up to 5 times the water depth. The shelf was surveyed from the 20-m to the 95-m isobath, over an area centered on the former Restricted Zone offshore of Fort Ord, from Moss Landing on the north, to Cypress Pt. on the south. Some of the notable findings that will be displayed at this symposium are: 1. A prominent north-south ridge, tentatively called the Fort Ord ridge, of very high backscatter and 6-m relief, composed of westward-dipping (5-degree slope) sandstone ledges, down-faulted on the east. 2. A series of flat-floored troughs, with coarse sand bottoms are strung out northward from Monterey along the coast between about 15 m and 30 m and culiminate in a large trough off Ft. Ord that extends to 58 m depth. These features may be caused by fresh-water seeps or acquifer outcrops. An alternate explanation is that these troughs are the locus of rip-current offshore transport of coarse sands. 3. The north Monterey County outfall pipe, which delivers storm-drainage and treated wastewater to a location about 1 mile offshore Marina, is prominently displayed as a high-backscatter, 2-m-high lineament. The pipe has caused sediment to pile up on its north side.
Engel, Jonna and Rikk Kvitek
Moss Landing Marine Labs
THE IMPACT OF COMMERCIAL TRAWLING ON A BENTHIC COMMUNITY WITHIN MONTEREY BAY NATIONAL MARINE SANCTUARY
Waters within Monterey Bay National Marine Sanctuary have been fished extensively by drag fishermen for nearly a century. This study compares an area trawled heavily since the 1930's to a lightly trawled adjacent area closed to trawling until 1970. Trawl logbook data confirmed that fishing pressure was higher in the "heavily trawled" (HT) than the "lightly trawled" (LT) area. Sediment grain size and percent cover or density of trawl tracks, rocks, mounds, pits, shell fragments, floculent matter, and exposed sediment were measured in each area. Sediment grain size analysis found the study areas to have similar sediment characteristics. Still photos and video transects showed significant differences betweeen areas. Biomass and density of invertebrate infauna and epi-fauna were measured in each area. Smith McIntyre grab samples were analyzed and significant biological differences included 25% fewer polychaete species but 36% more individual polychaetes in the HT vs. LT areas. The amphinomid polychaete, Chloeia pinnata, was 3 times more abundant in the HT vs LT area. Video transect data showed that most large invertebrate epifauna were significantly more abundant in the LT vs. HT area. Perhaps the most interesting result is the positive relationship found between polychaete biomass and trawling intensity. This association suggests that certain fish prey species may be enhanced by trawling disturbance.
Fernandez, Daniel M., and Craig M. Wittenbrink
University of California Santa Cruz
REAL-TIME ENVIRONMENTAL INFORMATION NETWORK AND ANALYSIS SYSTEM
REINAS (Real-time Environmental Information Network and Analysis System) has been developed at UC Santa Cruz in cooperation with MBARI and the Naval Postgraduate School. REINAS consists of an extensive network of instrumentation, database, and visualization support to allow both real-time and retrospective viewing of the data that is collected. The basic suite of instruments that are connected to the network consist of an array of MET stations, several wind profiler radars, and a set of three CODAR surface current monitoring radars (owned by NOAA and NPS). Other instruments include buoy-mounted ADCP's and CTD chains, owned by MBARI, a CTD owned by Pacific Fisheries in Monterey, and GOES satellite images. Data collected, queried, and visualized by the REINAS system is useful for demonstrating relationships between various environmental features, such as the influence of the seabreeze on the development of ocean surface currents and ocean waves. Operational users and forecasters also receive benefit from this system for assessing current conditions and for setting up boundary conditions for models as well as for verifying model output.
Fox, Laurel and Margaret FitzSimmons
The University of California, Santa Cruz
THE MONTEREY BAY REGIONAL STUDIES PROGRAM
The University of California at Santa Cruz recently initiated an interdepartmental, multi- disciplinary program of research and training (the Monterey Bay Regional Studies (MBRS) program) focused on regional coastal processes and their relation to specific regional issues. MBRS focusses on othe health, integrity and maintenance of the Monterey Bay regional system, including the well-being and productivity of the physical and biological components and the patterns of human adaptation to, and uses of, coastal environments. The major goals of the MBRS program are: ÷ to seek broad-based cooperation with the many researchers, public agencies, industries and private groups interest in the Region ÷ to identify and develop cross-disciplinary linkages between the university community and the region ÷ to identify and develop new, regional opportunities for research ÷ to identify regional needs and seek linkages between research, education and outreach
Toward these goals MBRS has begun 1) "demonstration" projects on relevant regional issues; 2) an annual series of public meetings"Challenges for the Monterey Bay Region"; 3) regular, informal meetings on regional topics that emphasize multidisciplinary research; 4) a training program for graduate students to provide multidisciplinary training around critical regional issues.
The specific demonstration projects are: 1) effects of reserves on rockfish fisheries, biotic communities, economics, etc., 2) Fort Ord, maritime chaparral and land management issues; 3) Elkhorn slough, land management and the slough interface.
Garfield, Newell, Curtis A. Collins, Robert G. Paquette, Everett Carter, and Thomas A. Rago
Naval Postgraduate School, Department of Oceanography
SUBSURFACE CURRENT MEASUREMENTS IN THE MONTEREY BAY MARINE SANCTUARY FROM NEUTRALLY BUOYANT RAFOS FLOATS, 1992-1994
The trajectory patterns of 22 RAFOS floats launched off of Monterey Bay and the Farallon Islands are used to investigate subsurface flow patterns along the continental margin in the eastern Pacific. Three general circulation patterns have emerged: transport poleward in the California Undercurrent, reversing flow parallel to the continental margin, and general westward movement, primarily as eddy transport, into the ocean interior.
Greene, H. Gary (1), Mary Yoklavich (2), Joe Clark (3), Deidre Sullivan (4), John Martin (5), and Greg Cailliet (1)
1. Moss Landing Marine Laboratories
2. NOAA, National Marine Fisheries Service, Monterey
3. Indiana University of Pennsylvania
4. Hartnell College, Salinas, 5University of Florida
OIL AND FISH - CONSTRUCTION OF CARBONATE HATITATS IN SOUTHERN MONTEREY BAY
In 1912 a wildcat oil-exploration well was drilled in Seaside, near the coast and along what is now the boundary of the Monterey Bay National Marine Sanctuary. This rush to find oil resulted from an ". . . explosive outbreak of gas and asphaltic oil in Bay not far from shore . . . " (Newcomb, 1941), which occurred shortly before drilling the well. No oil was found but hot (~100oF) sulfurous water flowed into the drilled hole. Today a shopping center overlies this well. Eighty-one years later (in 1993), a geophysical survey conducted to characterize fish habitats in southern Monterey Bay discovered a carbonate mound in 89 m of water that may have resulted from the "explosive outbreak". This mound rises 4 m above the seafloor and is located within the Monterey Bay fault zone along strike with the onshore well. Carbon-oxygen isotopic analyses indicate that these carbonates probably were deposited from the flow of warm meteoric waters. The water apparently traveled along faults and up along bedding to the seafloor, resulting in the construction of structures that now attract rockfishes. We suspect that many other such structures exist within the Monterey Bay fault zone of southern Monterey Bay, and are potential rockfish habitats.
Hampton, Monty A., John R. Dingler, Thomas E. Chase, and Henry Chezar
U.S. Geological Survey
RETREAT OF A WEAKLY LITHIFIED COASTAL CLIFF DURING A HIGH-RAINFALL YEAR, SAN MATEO COUNTY, CALIFORNIA
Landward retreat of a weakly lithified, sandy to muddy coastal cliff at Vallejo Beach, San Mateo County, CA during the high-rainfall season of 1994-1995 was primarily the result of landsliding, accompanied by debris flow, spring sapping, and gullying. The processes of retreat were influenced by physical properties of the cliff-forming sediment , surface runoff, and groundwater flow. Storm waves attacked the cliff occasionally, and their principal effect was to remove landslide debris from the base of the cliff rather than to undercut or oversteepen it and thereby induce slope instability, as reported for many coastal cliffs elsewhere. Landslides occurred in a variety of situations, mostly during or shortly after rainstorms. All had a steeply inclined failure surface, which maintains a nearly vertical cliff face, and were from a few inches to more than a meter deep. Some slides extended from the top to the bottom of the cliff (from 2 to 5 m), others first affected the lower meter or so and progressed upward, and yet others originated at the top of the cliff. Groundwater seepage near the base of a 1-m-thick surficial soil layer caused sapping and oversteepening that led to failure. Limited groundwater seepage from the base of the cliff caused slaking and small slides. Surface runoff, confined within shallow swales on the adjacent uplifted terrace, eroded large gullies into a limited section of the cliff and generated some debris flows. Between storms, some sections of the cliff sediment shrank slightly, which formed small prismatic blocks that tumbled from the cliff face. The cliff retreated up to a few meters during the rainy season, and despite areal variability of the processes and physical properties, the cliff edge remains relatively straight over its 500-m length.
Harvey, Jim (1), Kim Raum-Suryan (1), Rob Suryan (1), Tom Norris (1), and Dan Costa (2)
1. Moss Landing Marine Laboratories
2. University of California Santa Cruz
DISTRIBUTION AND ABUNDANCE OF MARINE MAMMALS NEAR SUR RIDGE, CA, THE FORMER SITE OF THE ATOC SOUND SOURCE
To determine the distribution and abundance of marine mammals near Sur Ridge, the former proposed sight of the Acoustic Thermometry of Ocean Climate (ATOC) sound source, shipboard line transect surveys (n = 13) were conducted from 25 July 1994 to 4 February 1995. Thirteen species of cetaceans and four species of pinnipeds were observed during 93.9 h and 1308 km of effort on 13 survey days. There were 117 pinniped sightings, 89 odontocete (dolphin and porpoise) sightings, 21 mysticete sightings, and 3 beaked whale sightings. Within the study area (2860 kmÊ), we estimated there were 945 pinnipeds (95% C.I. = 566 - 1577, CV = 0.27) and 2696 odontocetes (dolphins and porpoise; C.I. = 1119 - 6497, CV = 0.46) during visibility 2 (wind speed < 13 km/h, swell height < 2 m). Population estimates were not calculated for mysticetes or beaked whales due to small sample size. Determining a 20% change in density (power = 0.80) would require conducting 310 transects for pinnipeds during visibility 2 and 3, and greater than 1000 transects for odontocetes during visibility 2 (due to great variability and the few number of sightings).
Hobson, E. S., J. R. Chess, and D. F. Howard
Tiburon Laboratory, National Marine Fisheries Service
CHANGES IN NEAR-SHORE HABITATS RESULTING FROM REMOVAL OF RED SEA URCHINS, STRONGYLOCENTROTUS FRANCISCANUS
Near-shore marine habitats of the Mendocino coast were monitored over 20 years--1976 to 1995--and throughout the 10 years before the fishery for red sea urchins began in 1985 the sea floor below about 5 m was characterized by barren boulders with many urchins. Also, a seasonal bed of bull kelp, Nereocystis luetkeana, was restricted to a narrow band that paralleled the shore. Coincident with the sharp decline in number of urchins that followed the start of the fishery, there began a progressive expansion of the area forested by the bull kelp. During the next four years, the bed that developed each summer was larger than the bed of the year before. But during 1990, with the number of urchins still in decline, the area forested by bull kelp began a regression that coincided with the development of a dense algal understory, mainly Pterygophora californica. This development continued until 1992, when there began an influx of the herbivorous purple sea urchin, Strongylocentrotus purpuratus, into the area previously occupied by the larger red urchin. The purple urchins had been restricted to shallow water near shore, but now moved in dense aggregations into deeper water, completely removing the vegetation wherever they occurred.
Hodgins, M.M., H.F. Prest, and L.A. Jacobson
Long Marine Laboratory, University of California Santa Cruz
CONCERTED SAMPLING OF WATER FOR TRACE ORGANIC CONTAMINANTS BY BIVALVES AND SEMIPERMEABLE MEMBRANE DEVICES IN ELKHORN SLOUGH AND SOUTH SAN FRANCISCO BAY, CALIFORNIA
Bivalves have been widely applied as biomonitor organisms in detecting organic contaminants in aquatic environments. Recently semipermeable membrane devices (SPMDs) have been shown to be effective pre-concentrators of trace levels of organic compounds in water and air. This study compares accumulation of trace organic compounds in oysters (Crassotrea gigas), mussels (Mytilus californianus) and SPMDs deployed in two different estuaries; the primarily agricultural estuary, Elkhorn Slough and urban and industrial estuary of South San Francisco Bay. We report concentrations and trends in the profiles for organochlorines and polycyclic aromatic hydrocarbons (PAHs) in SPMDs and bivalves from a series of locations in both areas.
Hogan, Mary E. and Bess B. Ward
University of California Santa Cruz
ACCLIMATION OF AN ELKHORN SLOUGH MARINE MICROBIAL SEDIMENT COMMUNITY TO SIMULATED IN SITU EXPOSURE OF 2,4-DICHLOROPHENOXYACETIC ACID
Acclimation of an Elkhorn Slough marine microbial sediment community to the herb-icide, 2,4- Dichlorophenoxyacetic acid (2,4-D) was examined by comparing its ability to metabolize 2,4-D before and after exposure to the herbicide. The experimental treatment (2 week exposure) took place under simulated in situ conditions in an incubation chamber which maintained the physical and chemical gradient structure of the sediment community. The surface of the sediment was exposed to flowing seawater on a tidal cycle and 2,4-D (100 ppm) was added to the seawater so that its availability to the sediment microbes mimicked the natural situation. Before and after treatment, bacterial abundance, bacterial productivity and bacterial transformation of 2,4-D were determined. After the treatment, bacterial abundances were similar in the treatment exposed to 2,4-D and the control treatment (seawater only) indicating no chamber effect. Bacterial productivities were higher in the 2 week treatments compared to rates obtained from the mat prior to experimental treatment but this was not associated with 2,4-D exposure. 2,4-D transformation rates increased 28% in the 2 week 100 ppm 2,4-D treatment compared to the seawater control. This increased transformation rate indicates that the sediment community acclimated to the selective pressure of 2,4-D treatment by increasing its ability to utilize this compound as a substrate.
Johnson, Korie A.
Moss Landing Marine Laboratories
RECRUITMENT OF ROCKFISHES (SEBASTES SPP.) TO SOFT BOTTOM HABITATS IN MONTEREY BAY, CA
Many studies have recorded the recruitment of juvenile rockfishes to nearshore kelp beds and rocky outcrops within and around Monterey Bay, CA. However, the recruitment of young of the year (YOY) rockfishes onto soft bottom areas has not been examined. The purpose of this research project is to: (1) determine species composition of YOY rockfish in soft bottom areas; (2) compare YOY rockfish species composition on soft bottom to that of kelp beds and rocky outcrops; (3) assess the timing and density of rockfish recruitment to soft bottom habitats during 1995; (4) determine if there is a difference in juvenile rockfish abundance and species composition among depths and between the north and south part of Monterey Bay; and (5) interpret YOY birthdate distributions and timing of recruitment using corresponding oceanographic conditions. Sampling was conducted weekly from March 1995 to February 1996 aboard the RV Ed Ricketts using an otter trawl. Fifteen species of rockfish were collected, but S. elongatus, S. saxicola and S. levis, comprised over 90% of the catch. Abundances increased with depth and in the southern half of the bay. Peak abundances occurred in October and November.
Johnson, Korie A. and Gregor M. Cailliet
Moss Landing Marine Labs
THE OCCURRENCE OF TUMORS ON FLATFISHES IN MONTEREY BAY, CA
English Sole (Pleuronectes vetulus) and Dover Sole (Microstomus pacificus) with external lesions were caught using an otter trawl off Fort Ord in Fall 1994. We developed a sampling program to determine the distribution and abundance of these lesioned English and Dover sole with respect to the former Fort Ord Restricted Zone (FORZ), the Salinas River Mouth and the Pajaro River Mouth. Lesioned sole were found throughout the bay. Dover sole with lesions ranged between 6% and 10% of total Dover Sole caught. Lesioned English Sole ranged between 3% and 17% of total English Sole caught. Highest abundance of tumored Dover Sole occurred within FORZ, while the highest abundance of tumored English Sole occurred off the Pajaro River Mouth. English and Dover Sole with tumors were preserved, and samples of each were sent to The George Washington University Dept. of Pathology and the Environmental Protection Agency for histopathological analysis. Results from Dover Sole samples show the cause of the tumors to be amebic x-cells that have previously been found on Dover Sole in California. These x-cells are caused by unicellular protozoan parasites and are not linked to pollution. Lab analysis on the English Sole samples are still in progress.
Johnson-Conrad, Lynn E., Debra Stakes, and Jenny Paduan
Monterey Bay Aquarium Research Institute (MBARI)
AN INTERACTIVE GEOLOGY TOUR THROUGH SOQUEL CANYON, MONTEREY BAY, AS SEEN THROUGH THE EYES OF A ROV
The Soquel Canyon is a subsidiary submarine canyon to the Monterey Canyon in the Monterey Bay, CA. Since 1987 the Monterey Bay Aquarium Research Institute (MBARI) has conducted dives using a ROV (remotley operated vehicle) equipped with a high resolution video camera in the Soquel Canyon. Many of these dives have imaged the seafloor. We are developing statistical methods to determine rock type (e.g., sandstone, granitic, or volcanic) as well as rock unit (e.g., Monterey Fm. or Santa Margarita) based on characteristics of the rocks determined from digitized video. Rock determinations are groundtruthed using samples collected by the ROV manipulator arm or hydraulic coring system. Data is compiled into an interactive geologic map of Soquel Canyon. The canyon can be explored through bathymetric and shaded relief maps, outcrop maps, video images, photo-mosaics and movies. Key areas can be explored in more depth through photographs of rocks and petrological thin sections, descriptions of rock samples, graphs and tables of geochemical data, and other physcial parameters about the seafloor and water column. We find the interactive approach a useful way to convey large amounts ofdata to audiences with varying interests and levels of expertise.
Lander, M. (1), J.T. Harvey (1), K. Hanni (2), and L. Morgan (2)
1. Moss Landing Marine Laboratories
2. The Marine Mammal Center
ASSESSMENT OF REHABILITATED AND FREE-RANGING HARBOR SEAL (PHOCA VITULINA) PUP SUCCESS IN THE WILD
Despite the increasing number of harbor seal (Phoca vitulina) pups admitted to rehabilitation centers, few studies have been conducted to compare behaviors and survival rates of rehabilitated harbor seal pups with wild harbor seal pups. The objectives of this study were to compare dispersal, diving behaviors, activity patterns, survival, and health status between rehabilitated and wild harbor seal pups. Stranded harbor seal pups recovered from Pebble Beach, Monterey County, California were admitted to The Marine Mammal Center, Sausalito, from March to May 1995. Blood samples were collected from pups before and after rehabilitation. Radio transmitters were attached to the heads of 15 rehabilitated pups that were released at Pebble Beach from 8 June to 23 July 1995. As a control group, 13 wild harbor seal pups were captured and 10 were radio-tagged at Pebble Beach from 31 May to 6 June 1995. Blood samples also were collected from wild pups. Maximum known distance dispersed by rehabilitated pups (mean=101.65 km, SD=51.59, n=10) did not significantly differ from that of wild pups (mean=135.92 km, SD=64.05, n=6; t=2.14, P>0.05). Mean duration of dives (mean=1.07 min, SE=0.10, range=0.15 to 6.90 min, n=13) and surface intervals (mean=0.44 min, SE=0.03, range=0.02 to 14.90 min, n=13) for rehabilitated pups did not differ significantly from mean duration of dives (mean=1.28 min, SE=0.26, range=0.15 to 6.70 min, n=5) and surface intervals (mean=0.42 min, SE=0.00, range=0.02 to 14.07 min, n=5; P>0.05) of wild pups. Rehabilitated pups were active (swimming, diving, and bottling) 86.7% of the time and hauled-out 13.3% of the time for the first 24 hours after release, whereas wild pups were active 68.4% of the time and hauled-out 31.6% of the time after capture. A two factor analysis of variance indicated a significant interaction between seal group and activity (P<0.05). Before radio transmitter failure, at least 47% of the rehabilitated harbor seal pups had survived, whereas at least 60% of the wild harbor seal pups had survived. White blood cell counts, red blood cell counts, total protein, and globulin values of rehabilitated harbor seal pups significantly differed (P<0.05) before and after rehabilitation. In addition, the same indices were significantly different (P<0.05) between rehabilitated harbor seal pups and wild harbor seal pups.
Levenson, D.H. and Schusterman, R.J.
Long Marine Lab, University of California Santa Cruz
COMPARATIVE PUPILLOMETRY IN THREE PINNIPED SPECIES
Pupillomotor response to white light was measured for one California sea lion (Zalophus californianus), one harbor seal (Phoca vitulina), and one Northern elephant seal (Mirounga angustirostris). The degree of pupillary dilation at various light levels as well as absolute pupil size in (near) total darkness were determined. A comparatively small pupil at any specific illuminance condition and a large absolute pupil size were considered to be indirect evidence of a highly light sensitive animal. The pupil of the Northern elephant seal was found to dilate only under extremely dim conditions, and had the largest absolute size. The pupil of the California sea lion dilated completely under relatively bright conditions and was 50% smaller than the Northern elephant seal pupil. The harbor seal pupil also dilated under relatively light conditions, and was the smallest in absolute size. Because the degree of pupillary dilation is proportional to the amount of retinal stimulation, the elephant seal retina is probably the most sensitive to light of the animals tested. The large absolute size of the elephant seal pupil further increases visual sensitivity by increasing light capture capabilities in low light conditions. The results obtained are consistent with our hypothesis that the deep diving Northern elephant seal will be more light sensitive than the shallower diving California sea lion or harbor seal because the elephant seal forages in a more light limited environment.
Lonhart, Steve I.
Dept of Biology, University of California Santa Cruz
SIZE-FREQUENCY DISTRIBUTION OF AN INVADING WHELK AND INTERACTIONS WITH NATIVE PREY IN MONTEREY BAY.
In 1980, a subtidal predatory whelk, Kelletia kelletii, was first reported in Monterey Bay. Prior to 1980, the range of Kelletia was Baja California to Pt. Conception, Santa Barbara, CA. The size range (29-122 mm) of whelks in Monterey Bay is less than the range (16-138 mm) of whelks in southern California. Mean size of the whelks in Monterey Bay has increased an average of 5.3 mm/yr since 1993 (ANOVA, P < 0.001). Adult copulation and egg deposition have been observed in Monterey Bay, but no recruits (<25 mm) have been found. In San Diego near Pt. Loma, whelk recruits were numerous and crawling on exposed surfaces of the reef. In Monterey Bay, whelks have been observed feeding on trochids (Tegula spp.), other molluscs, annelids and scavenging carcasses. Ongoing laboratory experiments to test feeding preferences indicate whelks choose species of Tegula over other trochids (Calliostoma spp., Lithopoma gibberosum).
Mason, Janet E.
Pacific Fisheries Environmental Group/SWFSC/NMFS/NOAA
THIRTY-FIVE YEARS OF COMMERCIAL PASSENGER FISHING IN MONTEREY BAY
The species of rockfish caught by recreational anglers in Monterey Bay over the last 35 years have changed, from shallow to deeper water species. The average size of the fish has changed as well. There are several factors that may have influenced these changes. Declining availability of the dominant nearshore target species may have promted boats to search for other species in deeper waters. At first larger fish were available in deeper water, but as fishing continued the average size of some of these deeper water species declined. The long life spans of many of these species may make them vulnerable to heavy fishing pressure.
Mason, John (1), Jim Harvey (1), Rick Starr (2), Tony Orr (1), and Pamela Byrnes (1)
1. Moss Landing Marine Laboratories
2. UC Sea Grant Ext. Program
GEOGRAPHIC INFORMATION SYSTEM (GIS) ANALYSIS OF SEABIRD DISTRIBUTION ON MONTEREY BAY, CALIFORNIA FROM 1992 TO 1994
The Geographic Information System (GIS) class taught by Rick Starr and Jim Harvey through Moss Landing Marine Laboratories (MLML) and California State University at Monterey Bay provided an opportunity for 16 students to analyze two and a half years of seabird data collected by John Mason, Jim Harvey, and Patience Browne of MLML. Seabird data were collected using fixed and random strip- transects on Monterey Bay. Birds within 200m of the boat were identified to species using binoculars. The GIS class compared seabird distribution on Monterey Bay using four variables: hydrographic season, sea-surface temp, water depth, and distance from shore. Each group was responsible for the analysis of seabird distribution in relation to one of the variables. In this poster, we present the hydrographic season data for three seasons (spring upwelling, fall, and winter downwelling). Seabirds were grouped into four seabird feeding guilds: aerial-pursuit divers, wing-propelled divers, foot- propelled divers, and plunge divers. Seabird sightings and ship track-lines were mapped for each season using the GIS for visual comparison. Total number of birds from each feeding guild were graphed by season. Monterey Bay was divided into three areas; north water <100m, south water <100m, and water >100m deep. There was less survey effort in the deep water than in the shallow areas. Aerial pursuers were observed most often in deep or near deep water. Plunge divers were observed most often during spring. Foot-propelled divers were observed most often in shallow water. Wing-propelled pursuit divers were distributed throughout the bay during winter and spring.
U.S. Geological Survey
RECENT BENTHIC FORAMINIFERAL BIOFACIES OF THE MONTEREY BAY SHELF AND CANYON SLOPES
The bottom biota of the Monterey Bay region includes an extremely diverse microfauna. Benthic foraminifers collected from a series of box and multi-cores from nearshore to bathyal depths in the Monterey and Soquel Canyons can be separated into three distinct biofacies. The shallowest biofacies, occurring from 0-50 m water depth, is comprised of calcareous perforate foraminifers dominated by Cassidulina limbata with abundant Elphidiella hannai, Cibicides lobatulus, Buccella frigida, Rotorbinella rosacea, Elphidium excavatum selseyensis and E. excavatum clavatum. An intermediate biofacies, comprised nearly exclusively of arenaceous foraminiferal species, is present from 50 m to the shelfbreak (~120 m): Goesella flintii dominates the fauna at 50 m, Ammotium planissimus at 70-90 m, and Reophax scorpiurus, Alveolophragmium advena, A. columbiense, and Gaudryina arenaria at 100- 120 m. Within this zone of concentrated arenaceous foraminifers on the outer shelf lies an anomalous deposit of highly biogenic sediment west of Fort Ord (50-80 m) which looks remarkably similar to sediments collected from Cordell Bank to the north and includes the calcareous perforate foraminiferal taxa Cassidulina tortuosa, C. californica, Cibicides lobatulus, Trifarina baggi, T. angulosa, Rotorbinella rosacea and Planulina exorna. The deepest biofacies occurs between 1100 and 1400 m on the slopes of Monterey and Soquel Canyons and contains a calcareous perforate fauna which is dominated by low-oxygen species Epistominella pacifica, Buliminella tenuata, Bolivina argentea, Globobulimina affinis, and Chilostomella ovoidea, reflecting the presence of dysaerobic waters.
Noble, Marlene (1), Kaye Kinoshita (1), Leslie Rosenfeld (2), Cynthia Pilskaln (3), Steve Eittreim (1) and Frank Schwing (4)
1. U. S. Geological Survey
2. Naval Postgraduate School
3. University of Maine
4. National Marine Fisheries Service
CURRENTS AND SEDIMENT MOVEMENT IN MONTEREY SUBMARINE CANYON.
Moorings were deployed for a year in Monterey Canyon across 1) a narrow portion (axis depth 1450 m), 2) a wider part (axis depth 2837 m), and 3) where the canyon cuts across the fan (axis depth 3223 m). Each had current meters, transmissometers and sediment traps. The currents were mainly tidal, with the largest speeds near the bed. Tides in the narrow portion were 4 times larger than at wider sections. A 3-day oscillation, seen at most sites, had large spatial scales. It was coherent across the canyon and from the shallowest to the deepest sites (horizontal separation 75 km). A sediment trap deployed 80 m off the bed in the narrow axis showed large particulate fluxes, 22-60 g/m2/day, and overflowed after 3 months. Subsequently, a very large turbidity event occurred that lasted 1 week. In 4 hours, the water column went from clear to very cloudy, the pressure changed and the water became slightly warmer and fresher. A large amount of material either slumped off the canyon walls or came down the canyon as a turbidity current.
Nuss, Wendell A.
Department of Meteorology, Naval Postgrdauate School
CHARACTERISTICS OF WINDS OVER THE MONTEREY BAY
Local meteorological observations are used to characterize the diurnal and longer term variability in the winds over the Monterey Bay region. Local surface observations from around the bay have been used to access the horizontal variability and to relate this variability to larger-scale flow interaction with the local topography. Several 915 Mhz wind profiler systems have been used to examine the vertical structure of several characteristic wind regimes. These observations have been collected as part of the REINAS project and begin to describe aspects of how the sea-breeze interacts with our local topography.
Oxman, Dion and Stephen J. Trumble
Moss Landing Marine Laboratories
COMPARISON OF THE FOOD HABITS OF HARBOR SEALS (PHOCA VITULINA) FROM ESTUARINE AND COASTAL ENVIRONMENTS IN MONTEREY BAY, CALIFORNIA
Prey identified from harbor seal feces collected along the Monterey Peninsula were similar to those found in samples collected in Elkhorn Slough (PSI=70.6), a shallow tidal embayment at the head of Monterey Bay. Cephalopods dominated the diet of seals in the estuary (%N=60.7) and along the coast (61.6%). The remaining 39.3% of prey eaten by seals in Elkhorn Slough were fishes, primarily benthic species including flatfishes (26.2%) and cusk-eel (19%). Similarly, 38.4% of prey consumed by seals in the bay were fishes (cusk-eel: 24.5%, flatfishes: 19.1%). Most prey consumed by seals in Elkhorn Slough did not occur in the estuary.
Although overall diet was similar between environments, there were significant temporal differences. Harbor seals in Elkhorn Slough consumed a more diverse array of species each season (mean H': 0.68- 0.82) than individuals along the coast (mean H': 0.40-0.68). Because cephalopods and spotted cusk-eel dominated the diet of seals in both locations during autumn and winter, there was a great degree of similarity (PSI's=67.5 and 80.5, respectively). Composition, however, differed between areas during spring (PSI= 39.7) because harbor seals in Elkhorn Slough consumed primarily octopus, spotted cusk-eel, Pacific sanddab, and Dover sole, whereas individuals along the coast ate mostly market squid. Diets were marginally similar during summer (PSI=61.7), due to the numerous rockfish consumed by seals at both locations. Individuals in Elkhorn Slough, however, also ate white croaker, Dover sole and cusk- eel, whereas seals in the bay consumed plainfin midshipman and Pacific hake.
Paddack, Michelle J. (1), Erin Hannan (2), and Nicole L Crane (3)
1. University of California Santa Cruz
2. Monterey Bay Aquarium
3. Oceanic Society, Hopkins Marine Station/Stanford University
MONTEREY BAY NATIONAL MARINE SANCTUARY BIODIVERSITY AND MONITORING PROJECT: RESULTS OF A STUDY ON MARINE PROTECTED AREAS
The MBNMS Biodiversity and Monitoring Project was established in 1994, and aims to set up permanent subtidal sites in the Sanctuary and 1)collect baseline and project specific data, 2)prepare species lists and abundance 3)collect data on a regular basis to document change 4) involve local research divers and lay divers in the sampling through a diver education and training program. During 1994 over 100 divers participated, and the first edition of a Monitoring Handbook for divers was completed. Our first year of sampling was focused on a specific project looking at marine protected areas as Marine Fishery Reserves (MFRs), and we sampled 16 sites: inside and outside of the Hopkins Marine Life Refuge, Point Lobos Reserve, and the Big Creek Marine Ecological Reserve in Big Sur. This study addresses two main questions: 1)does protection from fishing allow higher densities of fishes to persist in an area? 2) does fishing create a size selective pressure on a population? Our findings indicate that there are higher densities of fishes in MFRs, and that fishes inside MFRs are larger than fishes in adjacent fished areas. The data indicate differences among populations of benthic reef fishes, and that these differences may be created or augmented by fish behavior, habitat differences, and fishing pressure. These results are relevant to fisheries management of some nearshore benthic reef fishes, and offer support for the use of MFRs as an alternative management strategy.
Paduan, Jeffrey D., Leslie K. Rosenfeld, and Michael S. Cook
Naval Postgraduate School, Monterery
REMOTELY SENSED SURFACE CURRENTS FROM THE MONTEREY BAY HF RADAR NETWORK
Near-surface currents in Monterey Bay derived from a network of shore-based HF radars are presented for August-December 1994 and compared with those from April-September 1992. Focus is placed on the low frequency (2-30-day period) motions and on comparison of radar-derived currents with moored current and wind observations, ship-based ADCP observations, satellite-based surface temperature imagery, and surface drifter velocities. The radar-derived picture of the late summer mean flow is very similar in the data from 1992 and 1994, and is consistent with historical data. Flow is equatorward in the outer part of the bay, poleward in a narrow band nearshore, and is very sluggish in the middle of the bay. Low-pass-filtered time series of radar-derived currents are highly correlated with moored currents and with winds in the outer part of the bay. The vector time series are also coherent across a broad frequency band with currents typically in phase between 1 m and 9 m and with 1 m currents typically 40-60 degrees to the right of the wind. Overall, these results confirm the utility of CODAR-type HF radars for the study of coastal surface currents out to ranges ~50 km from shore.
Moss Landing Marine Labs
FEEDING AND REPRODUCTIVE ECOLOGY OF CASPIAN TERNS (STERNA CASPIA) BREEDING IN ELKHORN SLOUGH, CALIFORNIA
After a 12 year hiatus, Caspian terns (Sterna caspia) returned to breed in Elkhorn Slough, California in 1992. From 1993 to 1995 I examined food habits and population size of breeding pairs and their young. During 1995, however, the colony suffered extensive reproductive failure; thus, I began a toxicology study to determine the cause of reproductive failure. During the breeding season, population counts and prey items were recorded three to six times per week. During 1994, the dominant prey items were northern anchovy (Engraulis mordax) and topsmelt (Atherinops affinis); during 1995, shiner surfperch (Cymatogaster aggregata) was consumed in quantities equal to that of anchovy and topsmelt. During July 1995, all unhatched eggs and dead chicks were collected from the colony site and sent to the California Department of Fish and Game Pesticide Investigations Unit, Rancho Cordova, for analysis. For initially analyzed eggs, mean thickness of egg shells (x=0.286 mm, SD=0.007, n=6) was significantly thinner than mean thicknesses for eggs collected prior to 1947 (before the use of DDT) (x=0.346 mm, SD=0.015, n=5) and 1981 (x=0.334 mm, SD=0.018, n=25; Ohlendorf et al. 1985). Early results indicated that high levels of toxaphene, PCBs, and DDT metabolites (i.e. DDE) were present in egg and chick samples from the Elkhorn Slough colony. Sediments disturbed in the Pajaro and Salinas rivers from heavy flooding in March 1995 may be the source of the organochlorine pollutants.
Petruncio, Emil T., Leslie Rosenfeld, and Jeff Paduan
Naval Postgraduate School, Monterey, CA
INTERNAL TIDE PROPAGATION IN MONTEREY SUBMARINE CANYON
Observations of the baroclinic semidiurnal tide in Monterey Submarine Canyon obtained in April and October 1994 reveal bottom-intensified currents and cold-water "pumping" over the rim of the canyon. Downward phase propagation of the semidiurnal wave indicates upcanyon energy propagation at nearly the same angle as the slope of the Canyon floor. Analysis of HF radar current data shows the surface semidiurnal current ellipses to be amplified at the head of the Canyon and aligned with the bathymetry. Princeton Ocean Model simulations employing tidal sea level forcing with bathymetry and density stratification typical of the Central California coast reveal internal tide generation at the continental shelf break and at the foot, floor, and rims of an idealized submarine canyon. The strength of the internal tide in the model submarine canyon is shown to be largely dependent upon the depth of the canyon at its foot, canyon length, and floor slope. When the shelf is incised by a model canyon 30 km in length with a floor slope that is near-critical for the M2 (12.42 hr period) internal tide, several features of the internal tide in Monterey Submarine Canyon are reproduced, including bottom- intensified currents, upcanyon energy propagation, and cold water pumping near the canyon head.
Readdie, Mark D.
Dept of Biology, University of California Santa Cruz
COLOR PATTERN VARIATION ALONG A DEPTH GRADIENT IN AN ANOMURAN CRAB SPECIES, CRYPTOLITHODES SITCHENSIS
Cryptolithodes sitchensis has a wide variety of color patterns on its carapace, and it is assumed that the patterns serve as camouflage within the surrounding environment. Stratified random sampling was used in two different depth ranges at Hopkins Marine Life Refuge. Color patterns from each depth range were digitized and compared using multivariate analysis. The null hypothesis is that there will be a difference in the color pattern on the crabs' carapaces between two sample areas having different habitat compositions. If the color patterns are serving to protect the crab from predation, the colors and patches should match the colors and patchiness of the habitat in which it is found. Supporting results would indicate that predation is playing a significant role in affecting the distribution of the crabs in their habitats. Support for the alternative hypothesis would suggest that the distribution of color patterns may not be a result of predation pressure, but is possibly due to competitive interactions or food availability. Results and discussion will be presented in the poster.
Sohst, Bettina (1) and Harry F. Prest (2)
1. Institut fur Toxikologie, Kiel, Germany
2. Long Marine Laboratory, University of California Santa Cruz
PCBS AND PESTICIDES IN SERUM FROM MONTEREY BAY SHARKS.
Elasmobranchs represent an interesting group of animals to study for organochlorine (OC) contamination because of their position in the marine foodchain; relatively long life; significant differences from both fish and mammals; and their global distribution. However, to our knowledge, this report presents the first measurements of OC residues in shark serum. Blood samples were taken from pelagic sharks collected in Monterey Bay and from sharks found in Elkhorn Slough. The serum portion was separated, extracted, cleaned up and analysed. Although the most prevalent component in the serum of all sharks was p,p'=92-DDE, significant differences appeared in the chromatographic patterns of pelagic sharks versus those from Elkhorn Slough. Pelagic shark p,p'=92-DDE concentrations were around 1 ng/g serum and most other components were below the detection limit. Elkhorn Slough shark serum showed higher OC concentrations than found in the pelagic sharks. These differences between pelagic and estuarine sharks reflect in part differences between land based and globally distributed contaminants.
Dolphin Research Center, Grassy Key, FL
AN ASSESSMENT OF POSSIBLE HEARING LOSS IN A CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS) WITH KNOWN EAR INFECTIONS USING RELATIVE, ESTIMATED MINIMUM AUDIBLE PRESSURE (MAP) VALUES
An evaluation of the auditory sensitivity of a male California sea lion (Zalophus californianus) with no known maladies in either ear and a female California sea lion with recurring ear infections, abscesses, and drainage was conducted. Psychophysical methods, "staircasing" and "method of constant stimuli", were employed to determine minimum audible pressure (MAP) values at two different frequencies. MAP threshold values for 400Hz binaural tones were calculated to be 60 dB re 20 microPa for the male and 64 dB re 20 microPa for the female. MAP threshold values for 1 kHz binaural tones were calculated to be 62dB re 20 microPa for the female. Ranges of dB values likely to contain the MAP threshold value for both 400Hz and 1kHz monaural tones were estimated for the female. Results were concomitant for both frequencies: the female showed consistently better performance when tones were presented in just the left ear (62-66 dB re 20 microPa @ 400 Hz and 62-68 dB re 20 microPa @ 1 kHz) as opposed to just her right ear (66-70 dB re 20 microPa @ 400 Hz and 68-72 dB re 20 microPa @ 1 kHz). This may indicate that damage to ear structures from infections abscesses resulted in a greater reduction of auditory sensitivity in her right ear.
Starr, Richard M. (1), Lindquist, David (2) and Korie A. Johnson (1,2)
1. UC Sea Grant Ext. Program
2. Moss Landing Marine Laboratories
THE USE OF SONIC TAGS TO ASSESS ROCKFISH MOVEMENTS IN THE LANDELS-HILL BIG CREEK ECOLOGICAL RESERVE.
We recently began working on a project to assess movements of shallow water rockfishes in association with the Landels-Hill Big Creek Ecological Reserve (BCER). We are placing sonic tags on fish to provide a detailed account of rockfish home ranges and movements within and across boundaries of the BCER. In the summer of 1995, with the help of the Monterey Bay Aquarium (MBA) and the California Department of Fish and Game (CDFG), we completed two successful pilot studies. In the first pilot project, three different methods of attaching acoustic tags to rockfishes were tested at MBA. The treatment groups included oral insertion of tags, dorsal attachment of tags to the musculature just below the dorsal fin, and surgical insertion of tags within the abdominal cavity. Tag attachment techniques were assessed using the criteria of duration of tag retention, observations of abnormal or hindered swimming behavior, observations of obvious skin lesions, and weight gain or loss of treatment fishes over a six week period. Surgical insertion of tags proved the most successful attachment method. In the second pilot project, we tested sonic tags in the field at BCER. Two rockfishes were successfully tagged with surgically implanted sonic tags and were tracked for six days.
Stevenson, Andrew J. (1), H. Gary Greene (2), and Roberto J. Anima (1)
1. United States Geological Survey
2. Moss Landing Marine Labratory
LOCATION AND STRUCTURE OF THE SAN GREGORIO FAULT ACROSS THE NORTHERN MONTEREY BAY SHELF
Recently collected single channel high resolution seismic reflection profiles across the San Gregorio Fault Zone reveal a wealth of detail regarding the structure, morphology and recent activity associated with this tectonic element where it crosses the northern Monterey Bay shelf. The data was collected using a 475 Joule boomer as a sound source, with a central frequency near 1 Khz. Two receivers were used; a 20 element streamer for deep reflections and a 3 element streamer for shallower structures. Lines were run across the fault zone with a spacing of 150m (inner shelf) to 300m (outer shelf), and cover the fault from Ano Nuevo Cove (~ 5m water depth) to the outer shelf seaward of Santa Cruz (~250m water depth). The most striking feature visible in the seismic records is the large amount of compressional deformation associated with the fault, which has been interpreted as primarily a strike-slip feature. This compressional deformation in places affects the youngest sediments imaged in our profiles, suggesting it is ongoing at present. Further evidence of active compression can be seen where the wave planed bedrock surface formed during Quaternary sea level low stands has been warped and folded, and where anticlinal fold axes adjacent to the fault extend above the surrounding recent sediment blanket, forming linear bedrock outcrops parallel to the adjacent fault.
Tomich, Patty, Tricia Lowe, Matthew Edwards, Peter Hague, Andrea Meyer, Lisa Marrack, Barbara Plechner, Rafael Riosmena, Andrew De Vogelaere and Michael Foster
Moss Landing Marine Laboratories
RESEARCH IN THE PHYCOLOGY LAB AT MOSS LANDING MARINE LABORATORIES
The research interests of the Phycology Group at Moss Landing Marine Laboratories are centered around understanding the population and community ecology of marine plants, including seaweeds, marsh, and dune vegetation, and the ecology of animals closely associated with these plants. This poster presentation summarizes studies including: the effects of human trampling on marsh plant assemblages in Elkhorn Slough, the large scale patterns and causes of marsh loss in Elkhorn Slough, the relationship between water motion and rhodolith movement in the Gulf of California, the impacts of oil spills on intertidal organisms in Alaska, and population dynamics of the sea grass Phyllospadix and the subtidal algae Fauchea, Desmarestia, and Macrocystis in Stillwater Cove, California.
Trumble, Stephen J. and James T. Harvey
Moss Landing Marine Laboratories
FOOD HABITS OF HARBOR SEALS NEAR MONTEREY BAY, CALIFORNIA
To address seasonal variations of harbor seal (Phoca vitulina) food habits along the central coast of California, fecal samples were collected from offshore haul-out sites near Monterey during 1991 and 1992. Harbor seal fecal samples (N = 222) contained 2,233 individual prey items. Based on mean index of relative importance (IRI) and percent number (%N) for all seasons, octopus (O. rubescens; %N = 31.7) and market squid (L. opalescens; %N = 30.3) dominated the diet. Fishes consumed by harbor seals were mostly flatfishes (Pleuronectidae and Bothidae; %N = 31), spotted cusk-eel (Chilara taylori; %N = 9.5), and rockfishes (Sebastes sp.; %N =6.5). Fecal samples collected during summer reflected a diet consisting mostly of juvenile rockfishes, whereas cephalopods dominated the diet during autumn, winter, and spring. The importance of market squid in the diet of harbor seals inhabiting waters near Monterey was previously unknown. A comparison of seal prey items collected from fecal samples and trawl data (Cailliet et al. 1979) revealed a significant correlation during summer (rs = 0.50), but not during winter (rs = 0.24). No study to date has provided information on seasonal prey consumption for harbor seals that inhabit rocky substrata off the central coast of California.
Van De Werfhorst, Laurie C. (John Pearse, advisor)
University of California Santa Cruz, Dept. of Biology and Dept. of Environmental Studies
TRAMPLING IN THE ROCKY INTERTIDAL: REPEATED STUDIES AT NATURAL BRIDGES STATE BEACH FINALLY REVEAL SOME EFFECTS
A senior thesis study by Katherine Beauchamp in 1977-78 compared three areas on a rocky intertidal platform adjacent to Natural Bridges State Beach that differed in intensity of human trampling. Removal and identification of all organisms in small, 10-cm square samples within and outside mussel beds revealed little difference between the three areas. The only differences observed were lower densities of the tiny bivalves, Lasea spp., and the absence of the algae Pelvetiopsis limitata in the most trampled area. Debra Goldstein repeated the study 14 years later for her senior thesis in 1992, and found little difference either among the sites or from the earlier study, despite the increased level of trampling. I've examined the area again (1995) for my senior thesis, this time sampling larger quadrats (25-cm square) along parallel transect lines across the platform. Although species diversity, as determined by the Shannon-Wiener Index, was not different among the sites, species richness was higher in the less disturbed sites. More dramatic, mussel cover, with associated higher species numbers, increased with decrease in disturbance, while frequency of bare rock decreased. These results indicate that rocky intertidal assemblages can be very resiliant to human trampling, and that scale and design of sampling is important for evaluating the impact.
Van Sommeran, Sean R. and Thomas J. Neal
The Pelagic Shark Research Foundation
5 YEARS OF SERVICE: THE PAST, PRESENT AND FUTURE OF THE PELAGIC SHARK RESEARCH FOUNDATION
Compared with more commercially important groups of fishes, research on elasmobranch ecology and biology is sparse. However, enough information exists to suggest that most grow and mature slowly, and produce few young compared with other species of fishes. The low reproductive rate of many sharks implies that sharks should be highly vulnerable to current commercial fishing practices, and there is a history of collapse in past shark fisheries. Because of the increasing demand for shark meat and fins, there is concern about the potential for further reductions to already declining shark populations, and to populations of species of sharks that have not previously been fished for directly. The Pelagic Shark Research Foundation (PSRF) was formed as a nonprofit research and education group in 1990 to develop and assist scientific and educational projects that contribute to further understanding elasmobranchs, with an emphasis on projects which contribute to the conservation and management of these animals. Here, we detail the accomplishments and history of PSRF, some of our current research and educational projects, including an observation/tagging program at Ano Nuevo state park to study behavior and migration patterns in great white sharks, and discuss some of the projects being planned for the future. Moreover, we will illustrate ways in which the public can become involved in helping to contribute to our understanding of these animals.
Dept of Biology, University of California Santa Cruz
A NEW SPECIES IN THE PHYLUM KAMPTOZOA (=ENTOPROCTA) DISCOVERED IN MONTEREY BAY
Kamptozoans are sessile, marine, suspension-feeding invertebrates with a unique body plan within the animal kingdom. Because kamptozoans are tiny, they have been largely overlooked in most parts of the world, including Monterey Bay. A survey of the colonial kamptozoan fauna of Monterey Bay has now revealed the presence of a total of six species, three of which were not previously reported from this region. The first species is new to science, and is being taxonomically described. The second and third species were previously known only from the Vancouver Island region; finding these species in Monterey Bay has thus greatly increased their known ranges. The fourth and fifth species detected by this survey had previously been reported from this region. However, the type material for these two species has been lost, so I will designate neotypes from material I have collected. As a result, the type locality for three kamptozoan species (one new and two previously described) will be Natural Bridges, Santa Cruz. The sixth species found in this survey is a cosmopolitan, invasive species previously reported from San Francisco Bay and Monterey Harbor.
Wilson-Vandenberg, Deb and Carrie Wilson
California Department of Fish and Game, Monterey
UPDATE ON THE STATUS OF COMMERCIAL PASSENGER FISHING VESSEL (CPFV) CATCHES IN THE MONTEREY AREA, 1987 - 1995
The Central California Marine Sport Fish Project collects catch and effort information aboard CPFVs fishing for rockfish and lingcod originating from Monterey, Moss Landing and Santa Cruz. We have been obtaining species composition, fishing effort (catch per angler hour, CPAH), and fish lengths on a location specific basis since 1987 at a sampling level of 3 to 5% of these trips. While most species have not shown evidence of declines due to heavy fishing pressure (both sport and commercial) there have been several trends worthy of concern. These include declining CPAH of bocaccio and chilipepper, and declining mean length of canary and yelloweye rockfishes due to loss of adult fish from sampled catches.
Yoklavich, Mary M. (1), Valerie J. Loeb (2), Mary Nishimoto (2), and Brendan Daly (2)
1. Pacific Fisheries Environmental Group, Southwest Fisheries Science Center, NMFS/NOAA
2. Moss Landing Marine Labs
NEARSHORE ASSEMBLAGES OF LARVAL ROCKFISHES AND THEIR PHYSICAL ENVIRONMENT OFF CENTRAL CALIFORNIA DURING AN EXTENDED EL NINO EVENT, 1991- 1993
Rockfish are among the most abundant larvae in nearshore ichthyoplankton assemblages off central California. Warm events (e.g.,El Niño) can have disastrous effects on their recruitment. We surveyed young rockfishes during a recent El Niño (December 1991-June 1993). Anomalously warm, low salinity water nearshore suggested an onshore displacement of the California Current. Upwelling was reduced and delayed. Larval rockfish abundance was similar in both years of this warm event, and among the highest of historical estimates in this area. Larval growth did not differ between years. Rockfish larvae were more abundant and bigger at onshore stations in 1992, suggesting retention nearshore. Juvenile rockfishes were extremely rare in summer 1992, and in 1993 they were 20 times more abundant and substantially larger. Surviving fishes were born late during both years; upwelling occurred coincidentally during this period in 1993 but not in 1992. We document substantially higher abundance of juvenile rockfishes in 1993, possibly due to increased offshore transport and lower predation during the larval stages.