Nine years of rockfish surveys in the Strait of Juan de Fuca

For decades, biologists from the Seattle Aquarium have been informally monitoring bottom fish on rocky reefs in Neah Bay, Washington. Based on increasing concern over the long term stability of bottom fish populations in this area by both state and federal agencies, the Aquarium formalized monitoring in 2005 with diver-based video surveys to quantify bottom fish (rockfish and lingcod) diversity and abundance over time. Divers performed 100-meter video transects, devised to be non-invasive and repeatable, to assess diurnally active and relatively sessile bottom fishes over time. Transects were conducted in the Strait of Juan de Fuca each year in August from 2005-2013 at five permanently marked sites. Density and diversity of bottom fish species were determined by biologists counting fish via the archived video. Over the past nine years, there has been no significant difference in diversity and density of adult rockfish among sites or years, but there have been significant young of the year (YOY) rockfish recruitment events in 2006, 2008 and 2010, termed “jackpot recruitment events”. We also found that young of the year rockfish densities in the “jackpot” years were significantly correlated with lower sea surface temperatures. Rockfish recruitment may be generally poor because larval survival and settlement are dependent upon changing conditions such as climate, abundance of predators, oceanic currents, and chance events. Being long-lived allows the adult population to persist through many years of poor reproduction until a good recruitment year occurs, as in 2006, 2008 and 2010.This study may elucidate significant trends in rockfish diversity and abundance, that will influence long term management plans for rockfish conservation

Strange Condition; Sociability

Two one-act plays presented at John Carroll University, October 10-13, 2002.https://collected.jcu.edu/plays/1129/thumbnail.jp

Turbine Integrated Pitching System

The Cal Poly Wind Power Club (CPWP) tasked this senior project to design, manufacture, test, and deliver a mechanism to pitch the blades for their small-scale horizontal axis wind turbine. CPWP competes in the Collegiate Wind Competition (CWC) against schools across the country, and as such it was critical to comply with the provided competition rules in addition to the design requirement from CPWP. The purpose of the pitching mechanism is to improve the performance and efficiency of the wind turbine by allowing the blades to adjust angles with different wind speeds. Specifically, this project aimed to minimize hub size, minimize power draw, minimize axial depth, increase blade strength, decrease blade switch time, in addition to being a durable and lightweight mechanism. The mechanism was designed with safety and reliability in mind and has been integrated into the CPWP wind turbine. The system utilizes two actuators to push and pull a swashplate connected to a 4-bar linkage to create the rotational motion in order to effectively pitch the blades. The team used a combination of CAD software and physical prototypes to evaluate the effectiveness of the mechanism. All of the manufacturing was completed by the team in the Cal Poly machine shops using a combination of manual machines and CNC. In addition, the team conducted various component and mechanism testing, including full turbine wind tunnel tests to validate the design. The final product was delivered to CPWP in time for the CWC competition, where it was put to the test against other universities\u27 wind turbine designs

Relative Abundance of Sixgill Sharks (Hexanchus griseus) in Elliott Bay, Seattle, Washington

The Sixgill Shark Research Project is designed to address gaps in the body of scientific knowledge on bluntnose sixgill sharks (Hexanchus griseus) in Puget Sound. This project utilizes three interwoven techniques: (1) genetics research, (2) visual marker tagging, and (3) video analysis. Seattle Aquarium biologists monitor sixgill shark sightings reported by local divers (since 1999) and study their relative abundance in Elliott Bay under the Aquarium’s pier (since 2003). Here we report on our findings of relative abundance. Bluntnose sixgills are a species of conservation concern. Sixgills are listed as “near threatened” on the IUCN Red List. Living mainly at abyssal depths but also in the shallow waters of the Salish Sea, sixgills are thought to be long-lived and slow-growing, and appear to have established movement corridors and home ranges that remain relatively fixed over time. As apex predators they are important members of marine communities; and, owing to their life history characteristics such as a slow rate of maturity and low reproductive rates, are thought to be extremely vulnerable to exploitation. Here we present our findings of relative abundance of sixgill sharks in Elliot Bay during the two time periods that the research was conducted: 2003-2005 and 2008-2015. We present the number of individual sharks seen each night, number of sharks tagged, number of returning tagged sharks, sex ratios, estimated number of sixgills residing in Elliott Bay (using capture-mark-recapture techniques), and seasonal and long-term trends in abundance

Observations on abundance of bluntnose sixgill sharks, Hexanchus griseus, in an urban waterway in the Salish Sea, 2003-2012

The bluntnose sixgill shark, Hexanchus griseus, is a widely distributed but poorly understood large, apex predator. Anecdotal reports of diver-shark encounters in the late 1990’s and early 2000’s in the Pacific Northwest stimulated interest in the normally deep-dwelling shark and the reason for its presence in the shallow waters of the Salish Sea. Analysis of underwater video documenting sharks at the Seattle Aquarium’s sixgill research site on Seattle’s waterfront and mark-recapture techniques were used to identify individual sharks to answer simple questions about abundance and seasonality. Temporal changes in relative abundance in Puget Sound were reported from a controlled study site from 2003-2012. At the Seattle Aquarium study site, 45 sixgills were observed and tagged with modified Floy visual marker tags, along with an estimated 116 observations of untagged sharks. Mark/Recapture statistical model estimates based on video observations ranged from a high of 98 sharks observed in July of 2004 to a low of 0 sharks observed in several research events from 2008-2012. Both analyses found sixgills significantly more abundant in the summer months at the Aquarium’s research station from 2003-2005 than at any other time during the study

Decrease in Sightings of Sixgill Sharks, Hexanchus griseus, in Elliott Bay, Seattle, WA, United States, a Comparison Between 2003–2005 and 2008–2015

The Bluntnose Sixgill Shark, Hexanchus griseus, is a large predatory shark, has a worldwide distribution and is listed as near-threatened by the International Union of Conservation of Nature (IUCN). The Seattle Aquarium collected observations of free-swimming Sixgill Sharks in Elliott Bay, Washington, under the aquarium’s pier in 20 m of water from 2003 to 2005 and again from 2008 to 2015 using the same methodology. Compared to total Sixgill sightings between 2003 and 2005 (273) fewer total Sixgills were sighted at the aquarium’s research station between 2008 and 2015 (33). The reason for the observed decline in sightings in unknown but based on data from other studies on Sixgills in Puget Sound during the same timeperiod the authors hypothesize the decrease may be due to natural variability of juvenile Sixgill recruitment to Elliott Bay

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