In April 1791 Captain George Vancouver sailed from Falmouth, England, with an expedition well-outfitted and equipped with the finest scientific instruments available. His crew of approximately 150 men was handpicked. His flagship, the Discovery, was a sloop of war of some 340 tons. She was named after the ship on which Vancouver had accompanied the famous Captain James Cook on his last voyage of exploration. Both captain and crew hoped for discoveries that would rival those of the great Cook. The British Admiralty remained hopeful that the fabled "Northwest Passage" existed, and Captain Vancouver was instructed to make an extensive exploration of the Pacific Coast of North America during his voyage, particularly searching for evidence of any river or passage the might connect the Pacific and Atlantic Oceans.
In April, 1792, the Discovery entered the Strait of Juan de Fuca, excitement building on board at the thought that the entrance to such a passage might be found the further eastward they sailed. In mid-May an entrance to a long, narrow body of water that was almost fjord-like was discovered. The formation of this narrow body of water began over 3 million years ago, and its current "fishhook" shape was created by glaciers around 15,000 years ago. This narrow body of water is 61 miles long and has 242 miles of shoreline…..small wonder it initially caught the attention of Vancouver and his crew.
"Early on Sunday morning the 13th, we again embarked; directing our route down the inlet, which, after the Right Honorable Lord Hood, I called Hood's Channel…." Log entry HMS Discovery, May 13, 1792.
Their initial exploration showed that the "channel" jutted southwestward. It was clearly not the great entrance they sought and the expedition turned back northeastward in their quest. Interestingly, though he referred to it as a "channel" in his log, Captain Vancouver labeled it as a "canal" on the superb charts being created as part of the expedition of discovery, and "Hood Canal" it remains to this day. Hood Canal itself would remain a backwater of international events, not seeing much activity at all compared to other areas explored by Discovery and her crew.
Today Hood Canal is welcoming another group of explorers. Like their predecessors in 1792 they are looking for discoveries. They are researchers and divers with a deep and abiding love for the body of water now known fondly as "the Hood". The discoveries they seek today, however, are not new lands to be claimed but answers to a perplexing scientific problem….periodically parts of the Canal will literally "choke" due to a lack of oxygen. Researchers from the University of Washington and other state and tribal agencies have joined hands with select teams of volunteer divers to gather data from specific locations within Hood Canal that have been particularly effected by the lower oxygen level phenomena. Human populations have grown dramatically around Hood Canal since the days of George Vancouver and it has become an area popular for waterfront vacation homes, boating and fishing, as well as being home to the Bangor nuclear submarine base. It would be a simple thing merely to trumpet that the cause of oxygen depletion is due solely to the encroachment of humans in the ecosystem, but there is far more to the problem that that. Reports of "fish kills" in the Canal go back well over a hundred years, long before the advent of increased population and intense recreational and military use. While human activity surely must play a role, other extremely significant factors are also at play here.
The average width of Hood Canal is only 1 ½ miles, its narrowest point being only ½ mile wide and its widest being around 4 miles. The Canal's deepest depths exceed 600 feet, and average 500 feet in the central channel for much of its length. A vast "sill" exists at the entrance of Hood Canal. The entrance to Hood Canal is relatively shallow, only around about 150 FSW. Immediately south of the entrance, it suddenly becomes very deep, between 500 and 600 FSW. This situation at the entrance creates a condition that prevents efficient water exchange seasonally or with changing tides. Instead, this physical "sill" at the entrance tends to retain the water and estimates of complete water exchange rates are speculated to be in the range of years. This natural situation not only slows the flushing action of the Canal, it also negatively impacts deep water circulation. This situation causes Hood Canal to flush extremely slowly, taking around 6 months to complete the flushing process. This is one of the factors that have caused historic chronically low levels of oxygen, a situation that worsens with distance from the mouth to the head of Hood Canal.
Something as ordinary as the wind can also play a significant role in the lowered levels of oxygen within parts of Hood Canal. Research indicates that oxygen depletion may be partially due to simple changes in wind direction. The prevailing north wind generally pushes oxygenated water into the oxygen-depleted areas of the Canal. A sustained south wind can, in turn, cut off this source of oxygen. An extremely visible type of oxygen stress is the sudden appearance of dead fish and other marine life on beaches. Such "fish kill" events have been historically recorded in Hood Canal and have been recently recorded in 2002, 2003, 2004 and 2006. While these events have been relatively localized and the severity of them has varied, they typically occur in the late Summer and Fall. They are associated with an upwelling of deep low-oxygen water to the surface. Such an upwelling can be gradual due to the addition of newer, denser ocean water at depth or it can be extremely rapid due to southerly winds that push surface layers northwards, resulting in the upwelling of deeper waters. In fact, most of the recent fish kills were documented with a period of southerly winds immediately following a period of northerly winds. There has been some speculation that such fish kills may even be part of a natural 50-year cycle of oxygen levels in the Canal since there is historical documentation of such events in the past.
The waters of Hood Canal can also be highly stratified in terms of both temperature and salinity, upper layers often having dramatically different temperature and salinity levels than those of deeper levels. Such greatly stratified water resists efficient mixing, further contributing to the oxygen depletion problem in parts of the Canal. In a nutshell, the waters of Hood Canal are deep, stratified, and exchange extremely slowly…..none of which are good things for a marine environment experiencing a steadily increasing impact from human populations.
Increased human population, bringing with it "normal" run-off from homes, business and population centers, causes increased levels of nutrients such as septic and sewer contaminants, salmon carcasses from fish hatcheries, herbicides and fertilizers in the Canal. Such increases in nutrients in areas of poor water exchange can lead to massive algal blooms and huge increases in bacteria populations, leading to plunging levels of oxygen at local sites. This is particularly the case in the southern reaches of Hood Canal where there is normally such poor exchange. The human impact to the naturally "poorly-flushed" waters of Hood Canal is thus probably also a significant factor in oxygen depletion events over recent years.
The Hood Canal Dissolved Oxygen Program (HCDOP) was formed as a coalition of groups jointly conducting research in an effort to determine the reasons why oxygen levels are so persistently low in Hood Canal and whether human activities are a significant contributing factor to that depletion. Funding for the study is primarily federal with additional funds and resources being made available from local tribes, Washington state, and private sources.
In June of 2007 it was my honor and privilege to dive with a few of those "private sources". After an early morning ferry ride and a long drive into the woods of the Olympia Peninsula I found myself turning down a one lane road toward the waters of Hood Canal and a beautiful little marina appropriately named Pleasant Harbor. It was there that I was to meet the team – a dedicated group of divers donating their time and skills to gather long-term data for the scientists and researchers of HCDOP. Most government agencies don't have the training or the resources to field teams of trained divers, and volunteers have stepped forward to fill that gap. The program, known as the Hood Canal Diver Observation program, (also called HCDOP), has an established goal to document the behavior and distribution of marine life as dissolved oxygen levels change at specific locations within Hood Canal during the year. The diver observation program provides a conduit for the teams' observations of marine life impacts to be systematically collected, compiled, and shared with the several scientific and governmental agencies attempting to understand the complex issues faced in Hood Canal. The data collected by the volunteer dive teams is used to track changes in marine populations over time – in terms of population density and abundance, depth, and stress levels. Collected on an established time frame over an extended period, such data will be used to show both trends in abundance of various species as well as depth distributions, and how such trends may correspond with the dissolved oxygen levels in Hood Canal throughout the year. The Diver Observation Program is coordinated by Janna Nichols, an extraordinarily active board member of the Washington Scuba Alliance who leads each trip and is literally the "heart and soul" behind the project. On the day that I was to dive with them, other team members on hand were Phil Green, Jackie DeHaven, Ty Hillebrand and Sarah Hillebrand, all well trained by Janna in fish and invertebrate marine identification and briefed on the specific methods to be utilized in the gathering of data. Local dive charter operators, Don and Diane Coleman of Pacific Adventures, have donated the use of both the use of their dive boat, Down Time, and their time for the on-going project, insuring that Janna and her teams have high quality surface support. I have been struck by the enthusiasm and professionalism of everyone associated with this endeavor, and the Colemans are no exception to this.
The methodology utilized for the HCDOP dives does not vary for the sake of accuracy and each dive team follows a strict regimen. Marine life is observed and documented within four different and specific depth zones. Upon entering the water, each team immediately descends to 80 FSW and will begin surveying at that depth. Depths are adjusted based on current tidal heights so that each team begins the dive at the same depth/location as each previous team over time. Each diver within the team then documents marine life observed within a three-foot wide swath directly in front of him/her as the team ascends through each zone, which are established as:
80 FSW – 60 FSW:Zone 4
60 FSW – 50 FSW:Sub-Zone 3B
50 FSW – 40 FSW:Sub-Zone 3A
40 FSW – 20 FSW:Zone 2
20 FSW – Surface:Zone 1
Each diver is equipped with a pre-printed slate for numeric and anecdotal documentation of observed fish and invertebrate numbers. Additionally, each team carries at least one camera to accurately document any anomalies noted – particularly if irregular behavior or stressed animals are observed. Notes are also to be made of additional species sighted that are not included on the master list and any other unusual sightings or developments noted during the dive. Upon surfacing, each team correlates their data and prepares it for submittal. Definitely mission-oriented and NOT your typical "let's get wet" kind of a dive. The team was both serious and enthusiastic….and it was infectious. I found myself grinning in anticipation of dives that would be both enjoyable AND scientifically important.
My buddy for the dive would be Jackie DeHaven, a vivacious school teacher with hundreds of cold-water dives to her credit. Together with Team Leader Janna Nichols and Phil Green we would be the first group to enter the water. It felt good to dive with a team in which you can feel a strong sense of dedication and purpose. Striding off the stern of Down Time I felt the blast of cold water on my face as the dive commenced and the team slowly sank into the rich emerald depths of Hood Canal. I was the tag-along….a rather large appendage whose sole assignment was to take photos of the team doing their job. Freed of any requirements other than my own creativity, once the team reached the established depth and began surveying I flitted around them like a rather large bee, snapping photos of the divers as they deeply concentrated on the tiny little portion of the rocky wall directly in front of their mask face-plates. After a very short while I realized that so far as they were concerned I wasn't even there, so devoted to their task were they. Moving in unison almost glacially up the underwater slope of the wall, shoulder-to-shoulder, the team made note of anything that swam, crawled or skittered down a hole, their pencils darting up and down and their slates gradually filling with data. These people really know what they are doing and why….I felt like a bit of a punk.
Upon surfacing, once again it was all business – each team member transferring the data from the slates onto permanent log sheets and discussing any anomalies noted during the dive or unusual species that might have been noted. Captain Don Coleman turned Down Time toward the next designated survey site and the second dive team began donning their gear in anticipation of descending to do their part. I stood and watched as the forested shoreline of Hood Canal swept past and mused to myself about how satisfying the day had been – "Something worth doing is being done here….." During the dive I didn't see anything amazing in terms of rare species….no dramatic evidence or scenes of the impact of oxygen depletion…..but I did see a solid team of volunteers doing a behind-the-scenes job that few people know, or even care, about. The task they have taken on is one that will make a huge difference in the scientific understanding of the challenges faced by a body of water that they dearly love – "the Hood".
The Hood Canal Dissolved Oxygen Program (HCDOP) http://www.hoodcanal.washington.edu/
The Hood Canal Diver Observation program, (also called HCDOP), http://www.hoodcanal.washington.edu/observations/diver_observations.jsp
The Washington Scuba Alliance http://www.wascuba.org/
Pacific Adventures, http://www.pacadventure.com/