Microbiological water quality at non-human influenced reference beaches
in southern California during wet weather
John F. Griffith, Kenneth C. Schiff, Gregory S. Lyon, Jed A. Fuhrman
Although urban wet weather discharges may have elevated concentrations of fecal indicator bacteria
impacting water quality at swimming beaches, not all of these bacteria may arise from human sources.
In this study, the contribution of non-human fecal indicator bacteria was quantified by sampling coastal reference beaches in southern California. Samples were collected at beaches near stormwater discharges
from undeveloped watersheds and analyzed for total coliform, Escherichia coli, and enterococci. Surfzone
samples exceeded water quality thresholds >10 times more frequently during wet weather than dry
weather. Exceedences were greatest <24 h following rainfall, then steadily declined on successive days.
Early season storms exceeded thresholds more frequently, and by greater magnitude, compared to late
season storms. Large storms exceeded thresholds more frequently than smaller-sized storms, partly
due to the breaching of sand berms. When discharges did reach the surf zone, bacterial concentrations
in the wave wash were correlated with watershed bacterial flux.
©2009 Elsevier Ltd. All rights reserved
Reducing the Threat of Ship Strikes on Large Cetaceans in Santa Barbara Channel and Channel Islands National Marine Sanctuary: Three Case Studies
Leslie Abramson, Elizabeth Petras
In order to facilitate the involvement of the shipping industry as a stakeholder in the process of cooperative policy-making as well as support the Channel Islands National Marine Sanctuary (CINMS) and the Sanctuary Advisory Council (SAC) in its efforts to make science-based, cooperative policy decisions the study was undertaken. In it we will identify the social, economic and political constraints influencing the commercial shipping industry through interaction with the Southern California Marine Exchange, Terminal Operators and Shipping Agents in the Port of Long Beach. It is intended to clarify the various jurisdictions and stakeholders involved in commercial shipping behavior within Santa Barbara Channel and outline possible actions which could be implemented by these groups and agencies. The research will compile and analyze potential management actions in terms of economic and political feasibility versus expected ecological benefits. Is the potential risk reduction worth the cost to industry? Is it possible to create effective outreach and education materials for both the SAC and the shipping industry?
A New Home for an Old Friend Responsible Aquarium Stewardship
Authors: Caffery, S., Escue, D.
Editor(s): Walters, L., Zaleski, S.
This book was born out of a need to explain to our youngest home aquarium owners the importance of not releasing pets and plants from their fish tanks. As many of the home aquariums in the United States are “owned” by children 12 years old or younger, we consider it imperative to provide scientifically accurate, age-appropriate information that promotes environmental stewardship in the best way possible—by creating story books that are fun for families to read together!
First 2 Copies Complimentary
Additional Copies $5.00 each
Utilizing magnetic resonance imaging (MRI) to assess the effects of angling-induced barotrauma on rockfish (Sebastes)
Bonnie L. Rogers, Christopher G. Lowe, Esteban Fernandez-Juricic, and Lawrence R. Frank
The physical consequences of barotrauma on the economically important rocklish (Sebastes) were evaluated with a novel method using T2-weighted magnetic resonance imaging (MRI) in combination with image segmentation and analysis. For this pilot study, two fishes were captured on hook-and-line from 100 m, euthanized, and scanned in a 3 Tesla human MRI scanner. Analyses were made on each fish, one exhibiting swim bladder overinflation and exophthalmia and the other showing low to moderate swim bladder overinflation. Air space volumes in the body were quantified using image segmentation techniques that allow definition of individual anatomical regions in the three-dimensional MRIs. The individual exhibiting the most severe signs of barotrauma revealed the first observation of a gas-filled orbital space behind the eyes, which was not observable by gross dissection. Severe exophthalmia resulted in extreme stretching of the optic nerves, which was clearly validated with dissections and not seen in the other individual. Expanding gas from swim bladder overinflation must leak from the swim bladder, rupture the peritoneum, and enter the cranium. This MRI method of evaluating rockfish following rapid decompression is useful for quantifying the magnitude of intemal barotrauma associated with decompression and complementing studies on the effects of capture and discard mortality of rockfishes.
PDF of entire paper, courtesy of Canadian Journal of Fisheries and Aquatic Sciences
Fine-scale movement patterns, site fidelity, and habitat selection
of ocean whitefish (Caulolatilus princeps)
Lyall F. Bellquist, Christopher G. Lowe, Jennifer E. Caselle
The fishery for California groundfishes is managed using broad species complexes, although some non-groundfish species are managed similarly due to the perception of shared behavioral characteristics. This study integrates acoustic telemetry and a GIS to quantify movement patterns of one such species, the ocean whitefish (Caulolatilus princeps) in a marine protected area. Seventeen ocean whitefish were tagged and actively tracked over multiple 24-h periods to measure fine-scale movement patterns. Home ranges based on 95% kernel utilization distributions averaged 20,439±28,492 (±S.D.)m2. Fish were active during the day, foraging over sand habitat at depths averaging 21±8m, but were inactive at night, taking refuge near rocky reefs at depths averaging 15±7m. Seventeen additional fish were tagged with coded acoustic transmitters and passively tracked using automated underwater acoustic receivers for up to 1 year. Approximately 75% of these fish exhibited long-term (1 year) fidelity to home ranges in the study area. Results suggest that MPAs can be an effective means of protecting populations of ocean whitefish and based on their habitat associations, ocean whitefish can be managed separately from other reef associated groundfishes.
© 2007 Elsevier B.V. All rights reserved.
Blooms of Pseudo-nitzschia and domoic acid in the San Pedro Channel and Los Angeles Harbor areas of the Southern California Bight, 2003-2004
Astrid Schnetzer, Peter E. Miller, Rebecca A. Schaffner, Beth A. Stauffer, Burton H. Jones, Stephen B. Weisberg, Paul M. DiGiacomo, William M. Berelson and David A. Caron
Abundances of Pseudo-nitzschia spp. and concentrations of particulate domoic acid (DA) were determined in the Southern California Bight (SCB) along the coasts of Los Angeles and Orange Counties during spring and summer of 2003 and 2004. At least 1,500 km2 were affected by a toxic event in May/June of 2003 when some of the highest particulate DA concentrations reported for US coastal waters were measured inside the Los Angeles Harbor (12.7 mg DA L-1). Particulate DA levels were an order of magnitude lower in spring of 2004 (February and March), but DA concentrations per cell at several sampling stations during 2004 exceeded previously reported maxima for natural populations of Pseudo-nitzschia (mean = 24 pg DA cell-1, range = 0 - 117 pg DA cell-1). P. australis dominated the Pseudo-nitzschia assemblage in spring 2004. Overall, DA-poisoning was implicated in >1,400 mammal stranding incidents within the SCB during 2003 and 2004. Ancillary physical and chemical data obtained during our regional surveys in 2004 revealed that Pseudo-nitzschia abundances, particulate DA and cellular DA concentrations were inversely correlated with concentrations of silicic acid, nitrogen and phosphate, and to specific nutrient ratios. Particulate DA was detected in sediment traps deployed at 550 and 800 m depth during spring of 2004 (0.29 - 7.6 mg DA (g sediment dry weight)-1). The highest DA concentration in the traps was measured within one week of dramatic decreases in the abundances of Pseudo-nitzschia in surface waters.
River plume patterns and dynamics
within the Southern California Bight
Jonathan A. Warrick1, Paul M. DiGiacomo2, Stephen B.
Weisberg, Nikolay P. Nezlin, Michael J. Mengel3,
Burton H. Jones4, J.Carter Ohlmann5, Libe Washburn5,
Eric J. Terrill6 and Katie L. Farnsworth1
Stormwater river plumes are important vectors
of marine contaminants and pathogens in the
Southern California Bight. Here we report the
results of a multi-institution investigation of the river plumes across eight major river systems of southern
California. We used in situ water samples from
multi-day cruises in combination with MODIS satellite
remote sensing, buoy eteorological observations,
drifters, and HF radar current measurements to
evaluate the dispersal patterns and dynamics of the
freshwater plumes. River discharge was exceptionally
episodic, and the majority of storm discharge
occurred in a few hours. The combined plume
observing techniques revealed that plumes commonly
detach from the coast and turn to the left, which is
the opposite direction of Coriolis influence.
Although initial offshore velocity of the buoyant
plumes was ~50 cm s-1 and was influenced by river
discharge inertia (i.e., the direct momentum of the
river flux) and buoyancy, subsequent advection of
the plumes was largely observed in an alongshore
direction and dominated by local winds. Due to the
multiple day upwelling wind conditions that commonly
follow discharge events, plumes were
observed to flow from their respective river mouths
to down-coast waters at rates of 20 - 40 km d-1.
Lastly, we note that suspended-sediment concentration
and beam-attenuation were poorly correlated
with plume salinity across and within the sampled plumes (mean R2 = 0.12 and 0.25, respectively),
while colored dissolved organic matter (CDOM) fluorescence
was well correlated (mean R2 = 0.56), suggesting
that CDOM may serve as a good tracer of
the discharged freshwater in subsequent
and monitoring efforts of plumes.
The effects of barotrauma on the catch-and-release survival of southern California nearshore and shelf rockfish (Scorpaenidae, Sebastes spp.) (in press)
Erica T. Jarvis and Christopher G. Lowe
Two experiments were used to assess initial capture survival and short-term post-release survival of line-caught (range 18 to 225 m) southern California rockfish following recompression. Occurrence of external and internal signs of barotrauma was characterized across all species. Despite species-specific differences in the extent of barotrauma observed, initial capture survival of 19 rockfishes held in a live well for a 10 min period following capture was 68% overall. Overall survival of 17 rockfishes following recompression in cages for two days was also 68%. Short-term survival varied across species (range 36% to 82%) as well as the occurrence of external signs of barotrauma. The degree of external signs of barotrauma was not a significant predictor of initial capture survival or short-term survival. The most significant predictor of short-term survival was surface holding time, with short-term survival increasing with decreasing surface holding time. These results suggest assisted release of rockfishes, with short surface holding times, can significantly increase post-release survival and could potentially enhance rockfish conservation.
Bring That Rockfish Down!
Christina Johnson and Erica Jarvis
Sea Grant and the California Department of Fish and Game are partners on a new brochure for anglers, explaining how and why to return rockfish to depth quickly. A PDF of the brochure can be downloaded at no cost. You may also request a hardcopy by mail. Contact: Christina S. Johnson, 858-822-5334, email@example.com
This brochure was a collaborative effort of California Sea Grant, Oregon Sea Grant
and University of Southern California Sea Grant.
Printing was funded by the California Department of Fish and Game.
PDF | Online Version
PORT CONTINUITY PLANNING -
Maintaining the Region’s Economic Lifeblood
Proceedings of a Conference on Maritime Cargo Security
James A. Fawcett, Editor
This conference is the second sponsored by USC Sea Grant on the issue of maritime cargo
security. The meetings would not have been possible without the generous support of the
NOAA Coastal Services Center, Margaret Davidson, Esq., Director.
Maritime cargo security is an especially important issue in southern California, home to
the Ports of Los Angeles and Long Beach, the busiest marine cargo seaport in the United
States. The conference on which this proceedings reports was, furthermore, made relevant
by the diligent efforts of a wise and dedicated steering committee, whose members are
noted below. FuturePorts, an organization advocating robust port and supporting infrastructure,
a strong economy and green port technology, was instrumental in connecting the
theme of the conference to the users of the ports. Elizabeth Warren, its Executive Director,
served as an indispensable co-chair of the entire enterprise.
Status, Environmental Threats, and Policy Considerations for Invasive Seaweeds for the Pacific Coast of North America
Steve N. Murray, Linda Fernandez, José A. Zertuche-González
This report was prepared for the Commission on Environmental Cooperation at the request of Hans Hermann, Head of the CEC’s Conservation of Biodiversity Program. The goals of this report were to review the status of knowledge concerning invasive seaweeds for the Pacific coast of North America and to analyze the potential threats to the environment posed by these species; in additional, the aim was to examine selected policies and to suggest possible policy options for improving the ability of Canada, Mexico and the United States to address these threats. The contents of this report, including its recommendations, solely represent the opinions and findings of he authors, and do not necessarily reflect the views or policies of the Commission on Environmental Cooperation or the governments of Canada, Mexico and the United States.
Estimating Dissolved Inorganic Carbon Concentrations from Salinity in San Francisco Bay for Use in 14C – Primary Production Studies
A. E. Parker, J. Fuller, R. C. Dugdale
One of the most fundamental measurements used for characterizing marine environments is primary production, the production of organic matter from inorganic constituents (most commonly through photosynthesis). Primary production estimates are typically made using the radioactive carbon -14 tracer technique introduced by Steeman Nielsen (1952) where the investigator adds a trace amount of radioactive carbon to a water sample and quantifies the radioactive enrichment of particulate organic matter during an incubation period. The technique is dependent upon precise determination of both radioactive enrichment and ambient dissolved inorganic carbon (DIC) concentration in the sample. While determining radioactivity is relatively easy with the use of a liquid scintillation counter, direct determination of DIC concentrations is often more difficult as few laboratories have the necessary instrumentation available. Traditionally in oceanic studies, DIC concentrations were based on a constant approximate value of 2000 μmol L-1 (i.e. Eppley & Sharp, 1975; Sharp, personal communication, see “Notes”) or based on measurements of salinity and pH (Parsons et al., 1984). These methods of approximation can be made within a salinity range of 22 – 33 psu (Parsons et al., 1984) and are therefore of limited use for work in estuaries, such as the San Francisco estuary (SFE), where salinity varies between 0 and >33 psu. Previous 14C based estimates of primary production in the SFE required direct determination of DIC concentrations (e.g. Cole & Cloern, 1984, Jassby et. al.2002).
The Role of Ammonium and Nitrate in Spring Bloom Development in San Francisco Bay
Richard C. Dugdale, Frances P. Wilkerson, Victoria E. Hogue, and Albert Marchi
The substantial inventory of nitrate (NO3) in San Francisco Bay (SFB) is unavailable to the resident phytoplankton most of the year due to the presence of ammonium (NH4) at inhibitory concentrations that prevents NO3 uptake. Low annual primary productivity in this turbid estuary is generally attributed to the poor irradiance conditions. However, this may not be the only cause; spring phytoplankton blooms occur irregularly in north SFB only when NH4 concentrations are low, <4 μmol L−1 and NO3 uptake by phytoplankton occurs. Field measurements and enclosure experiments confirm the NH4 inhibition process to be the cause of low NO3 utilization most of the year. Detailed analysis of spring blooms in three embayments of SFB over 3 years shows a consistent sequence of events that result in bursts of chlorophyll. The first requirement is improved irradiance conditions through stabilization of the water column by stratification or reduced tidal activity. Second, NH4 concentrations must be reduced to a critical range, 1 to 4 μmol L−1 through dilution by precipitation and by phytoplankton uptake. This enables rapid uptake of NO3 and subsequent increase in chlorophyll. The resulting bloom is due to both the initial uptake of NH4 and the subsequent uptake of NO3. The NO3 uptake step is crucial since it is the larger nitrogen source and uptake occurs at higher rates than that for NH4 at the concentrations that occur in SFB. Existing models of light-limited, non-nutrient limited productivity in SFB require modification to include the NH4 inhibition effect. From measured NH4 uptake rates and initial concentrations, calculations can be made to predict the length of time that favorable irradiance conditions are required for the phytoplankton population to reduce ambient NH4 concentrations to non-inhibiting concentrations and allow bloom formation to begin. For Suisun Bay, the time required is so long that blooms are unlikely in any season. For San Pablo and Central Bays, these times are too long in summer but sufficiently short in spring to allow bloom development, depending on the ambient NH4 concentration prior to the productivity season. NH4 sources to SFB are primarily anthropogenic, from agricultural drainage and sewage treatment plants, and if not sufficiently diluted by runoff and precipitation can prevent development of the spring phytoplankton bloom. Attention should be paid to the form of N making up dissolved inorganic nitrogen (DIN) in nutrient-rich estuaries.
Port Governance and Privatization in the United States: Public Ownership and Private Operation.
In M. Brooks and K. Cullinane (Eds.), Devolution, Port Governance and Port Performance, Research in Transportation Economics,Vol. 17
James A. Fawcett
Available through Amazon.com and Elsevier
Elevated body temperatures of adult female Leopard Sharks, Triakis semifasciata, while aggregating in shallow nearshore embayments: Evidence for behavioral
Barbara V. Hight, Christopher G. Lowe
The leopard shark, Triakis semifasciata, is an abundant nearshore elasmobranch, ranging from Baja California, Mexico to Oregon, USA. Mature female leopard sharks have been observed aggregating in shallow embayments throughout California; however, it is unclear why only females aggregate in these shallow areas. The goal of this study was to determine if mature female leopard sharks selectively occupy the warmest areas of a shallow embayment, if free-ranging leopard sharks' body temperatures are significantly warmer during the day than at night, and to quantify temporal use of these shallow habitats. Visual observations of sharks' fine-scale movements within the shallows of Big Fisherman's Cove Marine Life Refuge (Santa Catalina Island) aggregation site indicated that sharks preferred the warmest areas of the embayment and moved to warmer locations over the course of the day (p<0.05). Active and passive acoustic tracking, along with archival transponder technology (Vemco: V13, V13-R256, VX32TP-CHAT tags respectively) of 16 sharks caught and tagged within this aggregation were used to monitor core body temperature, swimming depth, and movements. Sharks had significantly higher core body temperatures in the late afternoon (1700 h–2000 h) during the summer, showed increased fidelity to thermal refuges during the day and increased movement away from these refuges at night (χ2, p<0.05). Seasonal variations in warm, shallow water usage were also observed. Elevated core body temperature of mature female leopard sharks using warm shallow embayments will likely augment metabolic and physiological functions such as digestion, somatic growth, and possibly reproduction.
$2.00 (order form PDF)
Effects of temperature on dark respiration and the photosynthetic responses of Caulacanthus ustulatus (Rhodophyta), a new member of the southern California intertidal
Victor M. Galvan, Steven N. Murray
In the summer of 2000 Caulacanthus ustulatus was first observed in southern
California waters. Since then, this species has become very abundant at several intertidal sites where it
grows on articulated corallines, rockweed stipes, rock, mussel shells, and barnacles. Here we provide
the first reports of the effects of temperature on dark respiration rates and the photosynthetic responses
of southern California specimens of C. ustulatus. Maximum photosynthetic rates (P
max) ranged from
4.54 (≠ 0.35 SE) to 3.75 (± 0.29) mg O2g-1 dwt h-1 but did not vary significantly (ANOVA; P = 0.29)
over the tested temperatures (11, 14, 17 and 20 °C). Light-limited slopes (α) ranged from 0.0696 (± 0.01 SE) to 0.0582 (± 0.01) but also did not vary significantly (ANCOVA; P = 0.86) with
temperature. Similarly, temperature had not significant effect (ANOVA; P = 0.46) on dark respiration
rates, which ranged from 0.78 ± (0.16 SE) to 0.44 (± 0.11) mg O2g-1 dwt h-1 . Ic ranged from 12.8 (± 0.29 SE) at 17 °C to 7.1 (± 1.66) μmol m-2 s-1 at 11 °C. These data show that the photosynthetic
performance of C. ustulatus is similar over the range of temperatures encountered in southern
California and along the remainder of the California coast and suggest that C. ustulatus is able to grow
and likely establish populations throughout the entire region.
Don't Release A Pest
Susan Zaleski, Dr. Linda Walters, Phyllis Grifman
On a pier by the ocean a little girl is about to 'set free' her fish, but finds out how her good intentions could go wrong.
Animated film targeting pet owners, specifically those that have aquarium tanks, to not release their pets and plants into the environment because they may become invasive. The film uses the invasion of Caulerpa taxifolia as an example for why people should not release pets or plants into the environment.
Animated film can also be used as a teaching tool along with our curriculum that meets state of California and National Science standards!
Caulerpa Species Identification Key
Susan Zaleski, Dr. Linda Walters, Phyllis Grifman
Caulerpa Identification Guide
Cost of Shipping
A Forensic and Phylogenetic Survey of Caulerpa Species (Caulerpales, Chlorophyta)
from the Florida Coast, Local Aquarium Shops, and E-Commerce: Establishing A Proactive
Baseline for Early Detection
Wytze T. Stam, Jeanine L. Olsen, Susan Frisch Zaleski, Steven N. Murray,
Katherine R. Brown and Linda J. Walters
Baseline genotypes were established for 256 individuals of Caulerpa collected from 27 field locations in Florida (including the Keys), the Bahamas, US Virgin Islands, and Honduras, nearly doubling the number of available GenBank sequences. On the basis of sequences from the nuclear rDNAITS 1+2 and the chloroplast tufA regions, the phylogeny of Caulerpa was reassessed and the presence of invasive strains was determined. Surveys in central Florida and southern California of >100 saltwater aquarium shops and 90 internet sites revealed that >50% sold Caulerpa. Of the 14 Caulerpa species encountered, Caulerpa racemosa was the most common, followed by Caulerpa sertularioides, Caulerpa prolifera, Caulerpa mexicana, and Caulerpa serrulata. None of the >180 field-collected individuals(representing 13 species) was the invasive strain of Caulerpa taxifolia or C. racemosa. With one exception (a sample of C. racemosa from a shop in southern California belonged to the invasive Clade III strain), no invasive strains were found in saltwater aquarium stores in Florida or on any of the internet sites. Although these results are encouraging, we recommend a ban on the sale of all Caulerpa species (including ‘‘live rock’’) because: morphological identification of Caulerpa species is unreliable (>12% misidentification rate) and invasive strains can only be identified by their aligned DNA sequences, and because the potential capacity for invasive behavior in other Caulerpa species is far from clear. The addition of the Florida region to the genetic data base for Caulerpa provides a valuable proactive resource for invasion biologists as well as researchers interested in the evolution and speciation of Caulerpa.
The Effects Of Barotrauma On The Catch-And-Release Survival Of Southern California Nearshore And Shelf Rockfishes (Scorpaenidae, Sebastes Spp.)
Erica T. Jarvis
~ May 2007
Three experiments were used to assess initial capture survival, and short- and
long-term post-release survival of line-caught (18 to 225 m) southern California rockfish
following recompression. Initial capture survival of 19 rockfishes held in a live well for a
10 min period following capture was 68% overall (95% CI: 60% to 75%; n = 168).
Two-day survival of 17 rockfishes following recompression in cages was also 68%
overall (95% CI: 62% to 73%; n = 256). External and internal signs of barotrauma were
not significant predictors of initial capture survival or short-term survival. The most
significant predictor of short-term survival was surface holding time (logistic regression
model:Χ 2 = 8.63, p = 0.003, OR = 0.95). Fish recaptures and 2-year monitoring data of
acoustically tagged rockfish (n = 84) provided evidence of long-term post-release
survival of rockfish of at least 690 days.
PDF of Thesis
Article in SLATE
(A News Publication of the American Academy of Underwater Sciences)
Elemental signatures in the vertebral cartilage of the round
stingray, Urobatis halleri, from Seal Beach, California
Loraine F. Hale, John V. Dudgeon,
Andrew Z. Mason, Christopher G. Lowe
Although numerous studies have utilized elemental analysis techniques for age determination in bony fishes, little work has been conducted utilizing these procedures to verify age assessments or temporal periodicity of growth band formation in elasmobranchs. The goal of this study was to determine the potential of laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) to provide information on the seasonal deposition of elements in the vertebrae of the round stingray collected from Seal Beach, California. Spatially resolved time scans for elements across the round stingray vertebrae showed peaks in calcium intensity that aligned with and corresponded to the number of seasonal growth bands identified using standard light microscopy. Higher signals of calcium were associated with the wide opaque bands while lower signals of calcium corresponded to the narrow translucent bands. While a close alignment between the numbers of calcium peaks and annual growth bands was observed in round stingray samples aged 5 years or younger, this relationship was less well defined in vertebral samples from round stingrays over 11 years old. To the best of our knowledge, this is the first study of its kind to utilize ICP-MS to verify age assessments and seasonal band formation in an elasmobranch. The results from this preliminary study indicate that LA-ICP-MS elemental analysis of the vertebral cartilage of the round stingray may have potential to independently verify optically derived age assessments and seasonal banding patterns in elasmobranch vertebrae.
©Springer Science+Business Media B.V. 2006
Caudal Spine Shedding Periodicity and Site Fidelity of Round Stingrays, Urobatis halleri
(Cooper), at Seal Beach, California: Implications for Stingray-related Injury Management
Christopher G. Lowe, Greg J. Moss, Greg Hoisington, IV, Jeremy J. Vaudo,
Daniel P. Cartamil, Megan M. Marcotte, and Yannis P. Papastamatiou
Natural caudal spine replacement rates, population size and site fidelity of
round stingrays, Urobatis halleri (Cooper), at Seal Beach, California were determined to evaluate
the efficacy of clipping of caudal spines of stingrays to reduce injury to human beachgoers. Of the
2,183 stingrays caught, clipped, tagged, and released at Seal Beach, only 13 (0.06%) were
recaptured over a threeyear period, indicating a large, mobile population. Natural spine replacement
occurred between August–October, when a majority of rays were found with two spines. Monthly
catch rates of rays were variable, but positively correlated with the number of injuries reported by
beachgoers. There was no significant reduction in stingray-related injuries to beach goers at Seal
Beach over the period when stingray caudal spine clipping was conducted.
Monitoring Rocky Shores
Murray, Steven N., Ambrose, Richard F., Dethier, Megan N.
The purpose of this book is to provide interested investigators with the information needed to develop methods and procedures for carrying out key elements of a rocky intertidal field-sampling program. Critical discussion and evaluation of the various elements of an effective rocky intertidal field-sampling program are provided in the ensuing chapters. The book was written for research and agency scientists, agency manager, and advanced university students who might benefit from consolidated discussions and reviews of important sampling issues and field procedures for designing and evaluating field monitoring and impact studies performed on rocky intertidal macro invertebrates, seaweeds, and sea grasses. Emphasis is placed on describing and discussing options for held methods and procedures, with a focus on their use in monitoring programs and impact studies. Users are required to formulate their own study goals and study designs. Clearly, any effective study program must have clear goals and objectives and invoke robust study designs.
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