1997 Funded Projects

Thirteen peer-reviewed proposals and four developmental proposals were funded by the WC&PR Center during the 1997 field season.

PEER-REVIEWED PROJECTS

Richard Brodeur - In situ observations on the distribution and behavior of juvenile and adult walleye pollock (Theragra chalcogramma) in relation to oceanographic conditions in the Bering Sea

Mark Carr - An experimental test of predator-induced density-dependent mortality in a temperate reef fish

Paul K. Dayton - Elevated Invertebrate and Fish Production in Submarine Canyons: Effects of Macrophyte Detritus

Charles Fisher (Yr 2 of 2) - Growth and Productivity of Ridgia Piscesae and Trophic Interactions within Vestimentiferan Communities in Different Vent Environments

Chris Goldfinger (Yr 2 of 2) - Submersible and Remote Vehicle Investigations of Cascadia Forearc Processes: Forearc Deformation, Slope Failure, and Earthquake Potential

Lisa Levin - Controls on infaunal community structure at Pacific methane seeps

Douglas Nelson - Ecology and physiology of Beggiatoa sp. at Monterey Canyon seeps: A model of novel, sulfide-driven, bacterial denitrification?

Peter Rona (Yr 2 of 2) - Hydrothermal Plume and Diffuse Flow Imaging Sonar: Test and Application

Craig Smith - Early succession, persistence and seep affinities of whale-fall communities on the northeast Pacific slope

Fred Spiess - Applications and refinement of seafloor geodetic techniques on the Juan de Fuca Ridge

Richard Starr - Movements of fishes associated with natural refugia in Monterey Bay: Implications for marine reserves in fishery management

Janet Voight - Discriminating endemic from opportunistic predators at hydrothermal vents

Marsh Youngbluth - Predatory roles of siphonophores in Monterey Bay, California

Developmental Project

Richard Starr - Innovative technologies for fisheries applications: Gizmos that work. A proposed workshop on underwater sampling tools for fisheries

Cindy VanDover - International Deep-Sea Biology Symposium: Results from research supported by the West Coast and Polar Regions Undersea Research Center

Geoff Wheat - Demonstration dives in the Channel Island Marine Sanctuary

Paul Reilly/Mary Yoklavich - Support for the 1998 Western Groundfish Conference

Project Summary: Reliable stock assessment is an important component of the rational management plan for walleye pollock (Theragra chalcogramma) in the eastern Bering Sea. Pollock are presently assessed, in part, by acoustic/trawling research surveys during the summer months. Fish behavior (e.g., changes in orientation and aggregation) can result in biases of unknown magnitude in acoustic population estimates. It is of great scientific and economic interest to examine the schooling and orientation behavior of walleye pollock to improve accuracy of stock assessments. Using in situ observation from a submersible or ROV, together with traditional acoustic and trawl surveys, the effects of potential sources of bias in population estimates will be examined. At the same time, the proposed study will contribute valuable new information on the ecology and behavior of this important fish species.

There is a substantial amount of cannibalism on juveniles by adults during the fall months. Age-0 and age-1 walleye pollock also represent a major food source for other fishes, marine mammals an birds in the Bering Sea. The Pribilof Island region is a location where intensive mammal and bird predation on juvenile pollock occurs due to large number of breeding and rearing sites located on these islands. Relatively little is known about the smaller-scale (meters to kilometers) vertical and horizontal distribution patterns of juvenile pollock near these islands, which is the scale most relevant to predator-prey interactions. There are a number of unresolved questions concerning juvenile pollock schooling behavior that have not been able to be addressed with present sampling techniques. Little is know about the vertical and small-scale horizontal distribution and aggregation patterns of juvenile and adult pollock which may be related to survival. Another factor in the survival of age-0 pollock in the Bering sea my be the high abundance of large medusae in the summer, which may represent predators of, competitors with, or commensal hosts to juvenile pollock.

As a continuation of a previously funded NURP project, the distribution an orientation of both juvenile and adult pollock near the Pribilof Islands in the Bering Sea will be examined using a submersible or an instrumented ROV during the proposed 13-day study In concert with an ongoing study of the ecology of juvenile pollock and their role in the Bering Sea ecosystem, the diel activity and aggregation patterns of juvenile pollock and orientation with respect to other fish and the bottom will be examined. The video cameras will allow identification and quantification of the plankton an other nekton associated with pollock schools, as well as the bottom physiography and sediment type. Pribilof Canyon, an area of high productivity, will be examined for its importance to juvenile pollock and the predators that forage upon them. To detect whether juvenile fish are responding to the presence of the ROV or submersible and moving outside the sampling radius of the video camera, a self-contained multi-frequency acoustic package will be used. The association of pollock with gelatinous zooplankton will also be examine. Upon retrieval of the submersible or ROV, gelatinous zooplankton, juvenile pollock and midwater and bottom fish predators will be collected using various nets.

Project Summary: Two fundamental objective of marine/fisheries ecologists are to determine (I) the causes and consequences of spatial and temporal variability in population size, and (ii) the mechanisms by which populations are regulated and therefore persist over time despite the large fluctuations in abundance that are characteristic of many marine species. Understanding how and why populations vary in space and time is critical to the management of biological resources, both for purposes of conservation and wise exploitation (e.g., predicting year class strength to establish harvest quotas). Likewise, understanding the processes that contribute to long-term persistence of population within bounds (i.e., regulation sensu Walde & Murdoch 1998) is also of obvious importance to protecting and maintaining viable populations of endangered or harvested species. Population regulation occurs only when at least one of the per capita demographic rates (recruitment, immigration, death or emigration) is, at some time and some place, density-dependent (Hassell 1986, Murdoch 1994, Cappuccino and Price 1995). To date, marine ecologists have expended much more effort toward understanding the sources and consequences of population variation. Far less effort has been directed at understanding the mechanisms responsible for population regulation and persistence (review by Caley et al. 1996). Moreover, several recent studies of tropical and temperate fishes suggest that predator-induced mortality of recently settled juveniles may be density-dependent and an important mechanism for local population regulation. However, with the exception of three studies involving one species of coral reef fish (Hixon and Carr in prep.) and two species of temperate reef fish (Anderson 1993, Steele in review), experimental tests of this hypothesis have not been conducted.

This study proposes to test experimentally the hypothesis that early post-settlement mortality of a temperate reef fish (the kelp rockfish, Sebastes atrovirens) is density-dependent and that the mechanism for density-dependent mortality is predation. The experimental design involves a regression approach (6 density levels of recently settled rockfish) in order to test for a significant trend/slope in per capita mortality (i.e., proportional loss) as a function of recruit density (i.e., density-dependent mortality). Additionally, to determine if predation by piscivorous fishes (adult rockfish) is the mechanism for density-dependent mortality, recruit density will be manipulated orthogonally with presence/absence of piscivores (adult rockfish). Standard ANCOVA will allow assessment of the extent to which density-dependent mortality is induced by predation. Because manipulation of predators require exclusion cages, a third treatment is incorporated orthogonally to assess any artifactual effect attributable to the cages. The target species, kelp rockfish, is known to be amenable to the experimental manipulations proposed herein and is representative of an ecologically important and heavily exploited guild of nearshore species (rockfishes of the genus Sebastes) throughout the west coast of North America.

The results from this study will provide marine/fisheries ecologists with insight into the importance of predation induced mortality on recently settled reef fishes as a mechanism for population regulation. Simultaneously, it will indicate the potential extent to which variable larval supply determines the size and variability of local populations of temperate reef fishes. It will also extend and provide comparison with the finding of similar NURP funded study conducted in a coral reef system (Hixon and Carr - CMRC) to temperate system. Such information is critical to, and absent from, our understanding of long term persistence of reef fish population.

Project Summary: The submersible DELTA will be used above 330m and TURTLE and the advanced tethered vehicle (ATV) below. Data will be gathered at 150, 200, 300, 500, 700, 900, and 1,100m in the canyon and at reference stations in the shelf and slope. During year one we will thoroughly characterize the La Jolla submarine canyon system with regards to fish diversity and density, extent of detritus accumulations, invertebrate assemblages inhabiting the detritus and the effects of organic enrichment on the benthic macrofauna. Collections of detritus will be used to identify and quantify the detritus community and to enable comparisons with work done within the shallow reached of the canyon. Boxcores taken at each station will be used for sediment grain size, C-N content, and infaunal analyses. In year two some stations in the La Jolla canyon will be revisited to assess detritus patch persistence and detritus flow within the canyon. Three other submarine canyons from the Mexican border to Santa Monica Bay will be studied to determine the generality of the results generated in year one. Three stations will be visited in each canyon.

Project Summary: The growth rates and physiological condition of three distinct growth forms of R. piscesae on the Juan de Fuca Ridge (JdFR) at each of three replicate study sites for each growth form will be determined. Growth rates will be measured in clusters of vestimentiferans which have had the tubes stained with a chitin dye, surveyed with a temperature probe and either an in situ chemical analyzer or by discrete water sampling at the beginning and end of the experiment, and monitored with recording thermistor arrays during the intervening year. Thus, a size-specific one year growth increment for a size range of individuals from each characterized microhabitat will be measured. This tube elongation data can be used to calculate the productivity of R. piscesae under a range of environmental conditions, because anterior tube elongation in this species can be directly related to increase in soft tissue biomass. The one-year, size-specific growth data will also be used to estimate the ages of the vestimentiferans in the clusters, construct allometric growth curves for the vestimentiferans in each microhabitat, and model the age distributions of the populations.

New techniques will be developed and employed to make quantitative collections of vestimentiferans and fauna associated with the tube worms. The collection techniques are designed for collection of all animals within a defined area and will provide robust measures of biomass and density of vestimentiferans and associated fauna in each type of microhabitat. Theses techniques will be used to make collections of both stained and unstained clusters from each type of microhabitat. These techniques will be used to make collections of both stained and unstained clusters from each type of microhabitat. All associated fauna will be sorted, identified, quantified, and fixed or frozen for further analyses.

The nutritional relations among the tubeworms and their associated fauna will be determined by analysis of bacterial and animal tissue d13C and d15N values. The documented site-specific differences in vestimentiferan d13C values and expected site-specific differences in bacterial d13C values will allow a more in depth analysis of this data than is possible in most vent communities. Samples of at least four individuals of each species of associated fauna (as well as samples of R. piscesae and free-living bacterial material) will be frozen on board ship from every isolated collection from a characterized habitat. After analysis of the R. piscesae and bacterial material from each collection, the collections with significantly different d13C and/or d15N in these biological "end members" will be analyzed. More limited collections of mobile vent predators will be analyzed for identification of pathways for transport of tubeworm C and N to the surrounding fauna.

The types of data collected over the course of this study are essential to determine the productivity of these types of communities as well as to quantify the input of these autotrophic deep-sea communities to the surrounding fauna. A long-term goal of my laboratory, and several collaborators, is to develop a working model of biological energy flow within and through a hydrothermal vent community. The studies proposed here represent a major step in collecting the data for that effort as well.

The proposed study site is a portion of the Endeavour segment of the Juan de Fuca Ridge, where many other programs are underway and planned in conjunction with the ROBE component of the US RIDGE initiative. Thus, one can reasonably expect valuable input from other studies and the results form this study can be interpreted in the larger context of a variety of other related, simultaneous projects. Additionally, this study has been designed to facilitate close collaboration with several already funded programs as well as other investigators who are pursuing funding.

Project Summary: This project will address two separate processes that bear on the overall deformation of the Cascadia forearc: arc-oblique strike-slip faulting; and tectonic erosion of the southern Oregon margin. Both processes influence the strength of the forearc, which is thought to be a major factor in determining subduction earthquake magnitude.

Cascadia has experienced no historic subduction earthquakes but evidence of Holocene earthquakes in coastal bays along the margin point to its seismic potential. Deformation of the forearc by faulting may limit strain accumulation, and hence the ability of the subduction zone to produce great (M>9) earthquakes. Additionally, high interplate temperatures and evidence of low basal shear stress and interplate coupling imply that Cascadia's seismogenic locked zone may be very narrow, although its exact location remains uncertain. The extent and location of the locked zone are essential factors for earthquake hazard assessment in the Pacific Northwest.

The majority of active forearc deformation occurs offshore in Cascadia, therefore detailed offshore studies are ideal for assessing how oblique subduction stresses are accommodated, and the resulting seismic potential of the subduction zone. Recent work has shown that the Cascadia forearc is cut by at least nine obliquely-oriented strike-slip faults. These faults have high slip rates, and several of them deform both subducting and overriding plates. Also recently discovered are a series of probable large detachment slumps off southern Oregon. These slides may be caused by (1) over steepening of the wedge, (2) subduction erosion, or (3) extensional forces created by rotation and northward translation of the forearc. The deformation of the accretionary wedge by strike-slip faulting suggests that the margin is highly strain partitioned (between arc-normal or compressional and arc-parallel or shear components), thus weakening the forearc. Massive landsliding and detachment of large sediment volumes suggest that parts of the southern Oregon accretionary wedge are poorly coupled tot he subduction plate, thus reducing the overall coupled plate boundary area. Consequently, both strike-slip faulting and mass wasting affect the strength and location of the interplate "locked zone", the main determinant of earthquake potential.

The proposed work will involve detailed submersible and remote vehicle surveys of (1) left-lateral strike-slip faults at the deformation front where they deform both the subducting Juan de Fuca plate (abyssal plain) and the overriding North American plate (accretionary wedge) and (2) probable catastrophic slumping features. The proposed research will focus on the following questions:

How and at what rate is the Cascadia forearc deformed by strike-slip faulting in response to oblique subduction?

Is the southern Oregon margin undergoing tectonic erosion and what can a series of probable debris slides on the continental slope tell us about subduction processes, strain accumulation, and Cascadia subduction earthquake potential?

Two objectives are designed to address these questions:

Objective 1: To determine in which plate the left-lateral faults originate, how their character varies along the fault trace, and how the faults interact with the accretionary wedge. Detailed observations, sampling, and structural measurements along four of the faults in offshore Oregon and Washington, using a deep water submersible and remotely operated vehicle, will allow us to answer these questions.

Objective 2: To confirm that the origin of the anomalous terrain off southern Oregon is submarine landsliding, by sampling probable slump debris at the base of slope from the remotely operated vehicle. We will also investigate the headwall scarps for recent activity, and the slump scar and hummocky debris for the likely cause and nature of the hypothesized slide. Subsequent work will include modeling of tsunamis that might be generated by slides of this magnitude, and identification of future slide sites.

Both objectives will increase our understanding of subduction processes and the earthquake and tsunami potential of the Cascadia subduction zone. Geological and geophysical investigations are currently our only means of constraining possible earthquake scenarios in Cascadia, because seismological methods cannot be used without earthquakes. The earthquake and tsunami potential of the Cascadia subduction zone has great societal impact on cities and coastal communities in the Pacific Northwest.

Project Summary: Seep environments, where reduced compounds are vented from the seabed through dewatering or tectonic processes, are now known to be common features of the Pacific margin. To date most biological research on seep biota has focused on the distributions, taxonomy and nutrition of large, epibenthic taxa. Very little information exists about the organisms dwelling within seep sediments. We propose to examine the community structure of methane seep sediment fauna in the northeastern Pacific Ocean in relation to geochemical properties of the sediments and to the larger oceanographic setting (current systems, oxygen and productivity regimes). Four bathyal seep sites and adjacent non-seep sites will be sampled by submersible and ROV to characterize sediment geochemistry, macrofaunal and foraminiferal community structure and bioturbation regimes. The influence of epibiota (microbial mats, symbiont-bearing clams and tube worms) on infauna will be examined. An additional objective is to assess the nutritional sources of seep infauna, using stable isotopic analyses and enzyme assays. With this information we hope to determine the dependence of macrofaunal and forminiferal communities on reduced compounds associated with seeps. We propose to work off Oregon and Monterey, CA in year 1, and in the Gulf of Alaska and off southern California in year 2. Comparisons will be made of infauna from methane seeps to those of nearby non-seep bathyal environments, and among various low-oxygen, organic rich settings or hydrothermal setting (using existing data) I an effort to understand factors controlling the composition, diversity, lifestyles, nutritional properties and bioturbation regimes of seep communities. This research will place seep communities in a more general deep-sea context, effectively integrating an understanding of seep environments with that of other bathyal settings.

A substantial matching contribution (equal to 85% of funds requested from NURP) is being provided by the State of California and the SIO Directors Office for faculty, post-doc and technician salaries.

Project Summary: Bacteria identified by morphology as belonging to the genus Thioploca or Beggiatoa can dominate surficial sediments in a variety of deep-sea and near-shore marine environments characterized by significant subsurface concentrations of soluble sulfide. If the environments are also microoxic and anoxic, the strains of these filamentous, gliding, sulfur bacteria that proliferate are extremely wide by bacterial standards (12 to 160 µm) and contain a membrane-bound central vacuole, comprising about 80% of the cross-sectional area of a cell. Beggiatoa and Thioploca are the only bacteria in which such vacuoles have been reported, and these organisms can reach extraordinary population densities. The biomass of Thioploca spp., which dominates thousands of km2 continental shelf and slope sediments, can be as high as 120 g wet weight per m2 (excluding sheath); our data indicate that at the Clam Field seep (Monterey Canyon) the biomass of vacuolate Beggiatoa sp. may be 10-fold higher. In very pure samples from three different locations, these extraordinary bacteria contained 0.13 to 0.5 M (molar) nitrate averaged over their biovolume. Relative to ambient levels this represented approximately a 10,000-fold concentration.

Studies proposed to clarify the in situ ecophysiology of these uncultured dominate bacteria (as opposed to their genetic or pure-culture potential) have taken advantage of our ability to obtain 75 µm wide Beggiatoa filaments regularly form Monterey Canyon seeps in very high purity. We have demonstrated their occurrence through the top 8 cm of sediment, over which they appear to harvest all free sulfide. Because these sediments are anoxic and because we detected massive ammonia maxima in the Beggiatoa region, we believe that ammonia rather than dinitrogen is the product of their nitrate respiration. Proposed additional studies include an analysis of their in situ rates of consumption of potential electron donors (sulfide and organics) and electron acceptors (nitrate and oxygen). Studies using 14C-labeled organic and inorganic carbon compounds and assays of diagnostic enzymes will elucidate their chemolithoautotrophic and chemoorganoheterotrophic potentials. Studies of the time course of utilization and chemical transformations of their intracellular nitrate plus enzyme assays will further clarify their potential for denitrification vs. ammonia production. Analyses of how their biomass and metabolic capacity change with depth in the sediment cores will be combined with analyses of sediment gradients of sulfide, oxygen, and nitrate to round out our understanding of their in situ mode(s) of nutrition. These Monterey Canyon Beggiatoa are proposed as a model of an important link between the vigorous sulfur cycle of eutrophic marine sediments and the nitrogen cycle. If they prove to be denitrifiers, they will constitute the first readily accessible model of an ecologically dominant bacterium capable of removing significant combined nitrogen (as N2) from a marine ecosystem. Alternatively, if ammonia is their waste product, this points to an expanded role for nitrifying bacteria in these ecosystems.

Project Summary: To advance the development and application of a sonar system designed to characterize black smoker-type hydrothermal plumes and associated diffuse discharge as follows:

(1) To complete engineering tests (APL-UW acoustic test facility) necessary for application of a Doppler sonar capability which has been added to the sonar system to measure flow velocities within hydrothermal plumes and temperature fluctuations in diffuse flow in conjunction with imaging. Modification of the sonar system to image hydrothermal plumes and addition of the Doppler capability has been accomplished by prior funding.

(2) Apply the sonar system to image and to measure flow rates of buoyant plumes of black smokers at the northern Cleft segment of Juan de Fuca Ridge to test models of plume behavior and their dispersion into the surrounding ocean (IMS/Rutgers with APL-UW). This area has been designated by the NSF RIDGE Program as the priority site for development of a long-term ocean bottom observatory to monitor seafloor volcanic, tectonic, and hydrothermal processes.

(3) Use the Doppler signal not only to measure flow rates in the black smoker plumes, but also to measure water temperature fluctuations of diffuse venting associated with the black smokers employing algorithms already developed for this application (APL-UW with IMCS/Rutgers).

Summary of Research
Research comprises sea trials and data acquisition with a Mesotech 971 sonar system which has been modified to image black smoker-type hydrothermal plumes, to measure flow rates within the plumes, and to derive water temperature fluctuations in associated areas of diffuse hydrothermal flow. The system will be operated from a submersible (DSV TURTLE, SEA CLIFF or ALVIN contingent on availability) at a site designated by the NSF RIDGE program for the development of a long-term ocean bottom observatory (RIDGE Observatory Experiment: ROBE, 1993). The data will be analyzed for several purposes, as follows:

(1) Engineering: To evaluate system performance as part of development of the plume imaging sonar for use in submersible mode for studies of plume dynamics and diffuse heat transfer and for conversion to long-term seafloor deployment mode for monitoring the activity of hydrothermal fields.

(2) Hydrothermal plume processes: To test a basic assumption of plume theory that the rate of entrainment of ambient seawater into the buoyant plume is proportional to the rise velocity of the plume at the height of entrainment (Morton et al., 1956).

(3) Diffuse flow processes: To determine the temperature fluctuation field of an area of diffuse flow adjacent to black smokers and to evaluate the feasibility of remotely estimating diffuse heat flux over broad areas of seafloor with this new acoustic method; the few prior measurements of diffuse flow by more limited methods suggest that it exceeds heat transfer by black smokers in vent fields by a factor of 5 to 10 (Rona and Trivett, 1992; Schultz et al., 1992).

Project Summary: Deep-sea chemoautotrophic communities on whale carcasses are now documented from at least 6 sites in the North Pacific and 8 sites in the fossil record. Our studies indicated that taxonomically similar communities develop on lipid-rich whale bones throughout southern California, and that these communities share at least 7 species with the fauna from distant hydrothermal vents, and at least 4 species with northern California seeps. Nonetheless, little is known concerning (1) early faunal succession on freshly sunken whale carcasses, (2) the persistence times of whale-bone chemoautotrophic assemblages, and (3) faunal relationships between whale falls and nearby southern California seeps. Such information is essential to evaluating the dynamics of whale-fall habitat islands and their importance as dispersal stepping stones for sulfophilic species at the seafloor.

We thus propose to use an ROV to study three whale carcasses (two implanted and one natural) and one seep on the seafloor off southern California. The carcasses are of varying ages, allowing data collection at t=0.33 y, 1 y, 2 y, 3.4 y, 7 y and >14 y since carcass arrival at the seafloor. The seep (that in San Clemente Basin) is 50-120 km up-current from our whale falls, and thus a likely source of seep-fauna propagules. We will collect sediment cores, faunal and bone samples, and photographic data at various times from these sites to address the following hypotheses:(1) Fresh whale falls cause intense local organic enrichment that fosters a highly specialized (initially heterotrophic) resident faunal assemblage. (2) Components of this heterotrophic assemblage remain for years after disappearance of the whale soft tissue. (3) The persistence times of whale-bone chemoautotrophic assemblages are skeleton-size dependent, attaining > 14 y on the remains of large baleanopterids and < 7 y on small gray-whale carcasses. (4) The faunal assemblages at the San Clemente seep and the southern California whale skeletons share a number of species, but there is not complete community overlap. (5) For those species occurring I n both San-Clemente-seep and whale-skeleton habitats, significant gene flow can occur between seep and whale-skeleton populations. To test these hypotheses, 6 d of ROV (or submersible) time will be required in 1997, and 9 d in 1998.

This project will substantially improve understanding of the dynamics of whale-fall communities, and their potential influence on the dispersal and evolution of chemoautotrophic assemblages in the northeast Pacific. It will also provide the first data concerning deep-sea faunal response to intense local organic loading, yielding insights into community response to natural and anthropogenic enrichment events (e.g., deep-sea relocation of sewage sludge). Finally, through collaboration with a biotechnology firm, this project may provide cold-adapted, lipolytic enzymes with broad industrial applications in cold-water detergents.

Project Summary: Over the last decade or so our group has been developing methods of carrying out geodetic measurements on the deep sea floor, reasoning from analogy with the usefulness of such techniques in terrestrial settings that similar capabilities should be useful in submarine settings. Having devised and tested a number of essential hardware components we have made a variety of geodetic instrument installations starting in 1991 on the Juan de Fuca Plate and from 1994 on the Cleft Segment of the Juan de Fuca Ridge. Our dual long term goals are to demonstrate that relevant measurements can be made, while at the same time contributing to understanding the processes at work during crust formation in the vicinity of a representative portion of ridge crest.

The proposed roles of NURP in connection with this program relate both to the understanding of ridge crest processes, and to building a geodetic capability in undersea technology. Our proposal contains six aspects: Those related to understanding ridge crest processes: Determinations of the 15 baselines crisscrossing the ridge crest. The first resurvey of the depths of our vertical deformation profile. Downloading of data from the first year of operation of the Fiber Optic Strain meter.

Those relating to development of undersea geodetic technology: Determination of the environment immediately surrounding one of our transponders whose performance has been erratic. Examination of the manner in which our concrete benchmarks interact with the substrate on which they are placed. Documentation of the manner in which the 500 m long fiber optic cable has actually been deployed on the sea floor.

These operation are best carried out with submersibles such as Sea Cliff, and ROV's such as the USN Submarine Development Group ATV.

Project Summary: Recent stock assessments conducted by the Pacific Fishery Management Council (PFMC) have indicated large population declines for commercially harvested species. These declines have led to discussions about the need for alternative fishery management strategies, such as the use of marine fishery reserves. Although fishery reserves are rapidly being established, their effectiveness in fisheries management is poorly understood and refugium concepts largely are untested.

The existence of natural harvest refugia in Monterey Bay provides a unique opportunity to quantitatively test some of the proposed benefits of marine reserves. This two-year proposal is to study the range and frequency of fish movements inhabiting natural harvest refugia on the flanks of Soquel Canyon in Monterey Bay. Objective 1 is to track sonic-tagged rockfishes and describe species-specific home ranges and movements using hydrophones, submersibles and an ROV. Objective 2 is to test the hypothesis that large predatory rockfishes on the flanks of submarine canyons remain in a small home range and ambush prey as they are advected upslope or move up into the water column or onto the shelf to feed. Both objectives have implications for marine reserves as management tools and models of energy flow pathways relative to the Monterey Submarine Canyon.

Prior to submersible operations, at least six fish of two different species of rockfish will be captured from rocky habitats on the flank of Soquel Canyon. Acoustic transmitters will be surgically implanted in the large rockfishes using techniques that have been refined in laboratory and field tests. Vemco V16 series transmitters will be used in tagging operations. The transmitters will be 16 mm wide and 65-90 mm long, with a weight in water of 10-16 g. The targeted species of rockfishes are greater that 400 mm total length and weigh more than 3 kg. Fish will be tagged with pressure sensors to enable monitoring of vertical, as well as horizontal, movements. Transmitter power will be 153-159 dB re 1uP @ 1 m; allowing signal detection at a range of 1000 m under expected sea conditions.

Fish will be returned to dGPS locations from which they were captured, and tracked at first by surface vessels. Two weeks after tagging, a directional hydrophone mounted in a manned submersible will be used to locate and visually evaluate tagged fishes. The submersible will then be used to place an array of hydrophones and receivers around the shelter habitats frequented by tagged fish. The array of receivers will enable the continuous tracking of horizontal and vertical fish movements for an eight week period.

An understanding of fish movements is especially critical information needed to properly design reserve sizes, shapes, and locations. The results of this work should provide important information related to home range and frequency of emigrations from harvest refugia. This project will also provide information about the transfer of energy and materials between benthic and pelagic habitats.

Project Summary: Hydrothermal vents are perceived to be unique biological habitats where the scarcity of predators allows the continued existence of archaic invertebrate groups and biologically isolates the vents from resource-limited habitats on the surrounding ocean floor. Predators, however, occur at vents. Some forms seem to be specialized and restricted to vents; others, especially at Northeast Pacific vents, appear to represent taxa that are members of the normal abyssal fauna, unspecialized for the vent habitat. This latter group may be opportunistic in their use of vents, that is they consume vent-linked resources when they encounter the habitat, then return to their normal habitat of the abyssal ocean floor. Such opportunistic predators may be primary in dispersing vent-linked production through the ocean, but the information currently available allows the two types of predators to be distinguished only if where they occur (and don't occur) is known.

How a species scores in seven characters, including its abundance on, and off, the vent field, the distribution of its members within the vent field, the size range of individuals within the species in a vent field, their foraging pattern, reproductive effort and the stable carbon isotope signature in their tissues, is predicted to categorize the level at which members of the species exploit vent resources. If scores for predators such a majid and galatheid crabs and zoarcid fish, cluster into two groups, these characters will be shown to discriminate ecological forms. Basic biological data and the required specimens to score species for these characters can be collected using an ROV.

The characters predicted to discriminate predator types derive from evolutionary approaches to the study of ecology. Vent habitats, although considered to be unique, share with other, more familiar accessible habitats a physical regime dominated by environmental unpredictability. Predictions derived from these familiar habitats will accelerate the rate at which knowledge concerning vent biology is acquired, as the important questions become more clear. Without additional data gathered to test evolutionary questions, these habitats which may be critical in contributing nutrients and energy to the deep sea will remain, in the world's view, isolated areas in a sea of resource-limitation.

Project Summary: The cycling of organic matter in the midwater (30-1000 m) realm of the ocean is an important unresolved aspect of pelagic ecology. In this context, the roles of soft-bodied zooplankton, i.e., herbivores and omnivores such as salps and appendicularians and the carnivorous jellies such as sipohophores, ctenophores and medusae, are particularly enigmatic. Of these predators, siphonophores may exert the most significant impact in many coastal regions. In Monterey Bay, CA such animals are a conspicuous component of zooplankton communities in the upper 1000 m. However, the extent to which they are involved in carbon utilization, particle repackaging, and direct transport of material is unknown. A principal reason, of course, is because these animals are fragile and hence difficult to collect and manipulate. This study will use a remotely operated vehicle and the special collecting devices it supports to conduct quantitative assessments of predation by several species.

Siponophores are colonial animals, pan-oceanic in their geographic distribution and range downward from the surface to at least 5000 m. In length, colonies vary from a few mm to 40 m. They feed by extending tentacles that snare prey with adhesive, entangling and/or toxic batteries of nematocysts. The tentacles subsequently contract, pulling food items to digestive gastrozooids. These organs are elastic and allow consumption of several kinds of prey of various sizes and shapes, e.g., copepods, ostracods, krill, amphipods, chaetognaths, medusae, ctenophores, siphonophores, appendicularians, and fishes. Many siphonophore species are seasonally numerous, some perform extensive diel migrations, and most digest their prey in a few hours. Consequently, these predators are likely to be major regulators of plankton stocks throughout the water column.

The principal objectives of our research will be to: 1) quantify prey consumption by determining gut contents and digestion rates, 2) ascertain where colonies are most numerous and relate these patterns to the abundance (density per m3) of prey, to their foraging behaviors (e.g., diel migrations and search strategies), and to changes in water column features on vertical and seasonal scales, and 3) measure the carbon and nitrogen content of both predators and prey to develop predictions about the trophic consequences of predation by siphonophores.

Project Summary: In recent years the development of innovative technologies has enabled exciting new research in fisheries biology. As well as enhancing the examination of the biology of individual species, these tools have facilitated studies of both interspecific interactions and habitat characterizations, which are becoming increasingly important. The objective of this symposium is to bring together scientists who use a variety of proven technologies that are propelling fisheries science into an exciting new era. The topics will include a broad range of technologies, species and habitats. This symposium will, by spot lighting a diversity of techniques, increase the level of exposure and potential fro technology transfer between fields. Also, it will help us to understand and direct the future role of these tools in fisheries research. The day will be broken down into three parts. First, a morning session where 10 speakers will give 20-25 min talks. After lunch we will have 2 more speakers, then a 1 hr combined lecture and video series to introduce the innovative technologies and research programs of the Monterey Bay Aquarium Research Institute (MBARI). The symposium will then move to Moss Landing for a tour of the MBARI facilities.

Project Summary: Five Center-funded scientists/students were provided with travel support for the 8th Annual Deep-Sea Biology Symposium in Monterey California. A 6th scientist could not attend the Monterey meeting but will present results of center-funded research at the Ocean Sciences meeting in San Diego California (9-13 February 1998). A list of PI's and the titles of their talks are presented below:

Baco, A.R. - Phylogenetic relationships of whale-fall vesicomyid clams based on mitochondrial COI sequences.

Copley, J.T.P. - Gametogenic ecology of hydrothermal vent polychaetes from High Rise vent field, Juan de Fuca Ridge.

McHatton, S.C. - Nitrate by seep populations of Beggiatoa from Monterey Canyon.

Smith, C.R. - Whale-fall communities on the Northwest Pacific Slope: Succession and food-web structure.

Vetter, E. - Macrofaunal communities within and adjacent to a detritus-rich submarine canyon system.

Voight, J. - Assessing the endemicity of vent predators and resultant implications for the evolution of hydrothermal vent fauna.

Best student paper/poster awards of $100 were given to Sarah McHatton (UC Davis) and Allen Andrews (Moss Landing Marine Labs). Note that these awards were not restricted to Center-sponsored researchers.

Project Summary: Seven dives with the Delta Submersible were conducted. Judith Connor explored the possibility of using video frame captures, etc. for documenting dives. The goal was to develop a procedure for documenting dives in near real-time in a format thatis compatible with the MBARI data base and web server. John Rummel and Jack Engel conducted transects on their dives to get a better idea of the capabilities of the Delta and the possibilities of developing telepresences for remote science. Ted Blackman tested the NASA video stereo camera system.
This system in conjunction with software from NASA allows one to develop a 3-D virtual world from which one can better devise research strategies. Ted uses the same software that was developed for the Mars Lander. Geoff Wheat dove to get a better understanding of the capabilities of the sub and its crew. Charles Neveu and Nick Damato took one of the US Navy's laser line scanners into the sub to test it capabilities underwater. The curvature and thickness of the port sufficiently scattered the energy of the laser such that a solid return was not possible. This is the same system that was tested in the MBARI test tank and did resolved a complex structure in water at a distance of 6 m. Phil McGillivary was able to dive on the following day during which the Delta crew were testing a new mechanical manipulator.

Project Summary: The Western Groundfish conference has been held approximately biannually at various locations along the west coast since the first meeting in 1981. It is a unique forum for disseminating current research results and discussing management alternatives for some of the west coast's most valuable marine resources. The conference includes participants from Alaska, Washington, Oregon, California, British columbi, and often other US states. Attendees represent state and federal fishery agencies, regional fishery management councils, universities, conservation groups, and the fishing industry. Members of private research institutes and other marine industries typically participate as well.