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Donald M. AndersonPurpose This website is intended to provide background information as well as current observations and commentary on the status of Paralytic Shellfish Poisoning (PSP) outbreaks in the northeast United States. The content is provided for informational purposes only, and should not be used to guide recreational or commercial decisions regarding the harvesting of shellfish or other fisheries products within the region. Current Status - July 24, 2009 As a result of the continuing high levels of toxicity in Maine and the sighting of a very large red water patch of Alexandrium cells near Portsmouth on July 10 and 11, an event response cruise was conducted from July 19 - 23, using funds generously supplied by the NOAA National Ocean Service (NOS; see NOAA press release). The purpose of this cruise was to ascertain the abundance and distribution of Alexandrium cells in western and eastern Gulf of Maine waters, to provide guidance to managers concerned with both inshore and offshore toxicity. Results of that survey are shown in the cell distribution map. Throughout the large area that was surveyed, Alexandrium cell concentrations were low - maximally 100 - 200 cells/L. This is in stark contrast to the high cell concentrations that were present earlier in the bloom, and in particular, to those measured in the red tide patch (approximately 1.7 million cells/L). The cruise observations suggest that the 2009 Alexandrium bloom is nearly gone for much of the coasts of Maine, New Hampshire and Massachusetts. Several caveats are in order here. The first is that these low cell concentrations should not be interpreted to mean that shellfish are safe to consume. Shellfish species vary in their rates of detoxification, so shellfishermen and private citizens should refrain from harvesting any shellfish until state monitoring programs have reopened closed areas. There are still very dangerous levels of toxin in shellfish throughout the region. The second caveat is that toxicity in eastern Maine is believed to be linked to Alexandrium blooms that occur within the Bay of Fundy. Those blooms are ongoing at this time, so there is a possibility that some cell populations can leave the Bay of Fundy and impact eastern Maine. Therefore, its premature to signal the end of the 2009 bloom for that region. Note also that, although rare, fall blooms of Alexandrium do occur within the Gulf of Maine. In some past years, this has resulted in shellfish closures in September and even October. Thus the 2009 bloom season appears to be winding down, but there are possibilities for a continuation or resurgence of toxicity in eastern sections this summer as well as for a second bloom event in the fall. Looking back to the advisory we issued in April, in many ways this has been borne out since a significant regional event did occur that closed shellfish beds from the Canadian border to the middle of Massachusetts Bay, much as happened in 2006 - the year we used as an example in that advisory. However, there were aspects of the 2009 bloom that were not foreseen nor were they captured in our numerical model simulations, in particular, the high levels of toxicity throughout Maine, in contrast to the relatively low levels measured in Massachusetts. Its too soon for us to answer the question of why 2009 was so severe in Maine, and unfortunately this was not a year of GOMTOX cruises, thus we have very limited survey data to scrutinize for an answer. We do wonder whether the large amounts of rainfall as well as the lack of strong northeast winds (which can transport the Alexandrium populations from east to west) were factors in the observed toxicity patterns. As for future cruises - we do not anticipate any additional survey work during this bloom period unless something unusual happens and the bloom increases dramatically. We will, however, be out again in October when we will map the abundance of Alexandrium resting cysts. In the past, we have found a very strong linkage between the abundance of these cysts and the magnitude of the Alexandrium bloom in the following year. It is thus too soon to speculate about what might lie in store for the region in 2010, but we will be working towards an advisory this winter and should make it public in the spring. We wish to thank the National Ocean Service and all of the Congressional delegations who worked to obtain event response funding to provide valuable cell count information over the last week. This has been a difficult time for shellfishermen and many others in the region and it is welcome news that the outbreak is on the wane. Status - July 15, 2009 Field observations during 2009 will be very limited because this is an "off year" for survey cruises in the GOMTOX program. We are therefore piecing together an image of this unusual bloom from a combination of shellfish toxicity records from state monitoring programs and a few small vessel survey cruises. As 2009 began, our expectation was that we would have a "moderately large regional bloom"- meaning that in the western Gulf of Maine, we would expect toxicity through most of western Maine, New Hampshire and portions of Massachusetts, possibly including part of Massachusetts Bay. We envisioned a scenario similar to the 2006 year. To view the April 22, 2009 news release regarding the 2009 bloom advisory, please click here. These advisories are considered most relevant to the western Gulf of Maine region as the dynamics of populations to the east remain poorly understood and modeled. The bloom season began in a somewhat typical fashion, with shellfish toxicity being detected in western Maine and New Hampshire in early May (see PSP toxicity map). In past years, where there has been significant toxicity in the western Gulf, this was a time when we also had at least one, and often two, major northeast storms that pushed Alexandrium cells to shore, rapidly increasing toxicity and propellig the bloom to the south as well. Wind records for 2009 show a very weak northeaster in early May followed by a long interval with light and variable winds. These conditions were nevertheless sufficient to cause toxicity and harvesting closures along most of western Maine, New Hampshire and Massachusetts (south to the middle of Massachusetts Bay - see map), but shellfish toxicities were low and survey cruises revealed very low cell abundances as well within that region. The bloom season seemed to be winding down in the western Gulf, with the reopening of closed areas in June, suggesting that the major input of cells was over. Typically, toxicity in eastern Maine increases in mid summer as those waters warm, and 2009 was no exception. However, for reasons that remain obscure, the Alexandrium population "exploded" in the eastern Gulf causing rapid increases in toxicity in downeast Maine and extremely high levels of toxicity at some locations. Volunteer citizen observers found large numbers of cells in their samples at many locations along the coast. It would apear that the Alexandrium population thrived on the foggy and rainy conditions that persisted for most of the month of June. At this writing, we are concerned that the large populations from Maine are heading south, evidenced by the "red water" observed near Portsmouth, NH in a recent small vessel cruise (see photo) and also observed in a cruise near Cape Ann, MA (see map). So while Massachusetts and New Hampshire watch closely for a resurence in toxicity (and Federal managers anxiously watch the situation in offshore, Federal waters) Maine is struggling with one of the worst red tides in its history. This is best exemplified in the following text from Darcie Couture, Director, Biotoxin Monitoring, Maine Department of Marine Resources. The 2009 paralytic shellfish poisoning (red tide) event in Maine, which flared up while the state shellfish beds were still under a series of late spring flood closures, is ongoing at this time, and does not show signs of ending as of yet. Several benchmarks of this red tide event have already exceeded the record-setting red tide event in 2005:So, in summary, 2009 has been a signficant year for a toxic Alexandrium red tide, particularly in Maine. There are still many cells out in the water, and the potential for the situation to sustain itself, or even get worse. We will provide updates as they become available. History of PSP in New England Prior to 1972, PSP toxicity was historically restricted to the far eastern sections of Maine near the Canadian border, with the first documented PSP in Maine in 1958. In 1972, a massive, visible red tide of Alexandrium fundyense stretched from southern Maine through New Hampshire and into Massachusetts, causing toxicity in southern areas for the first time. Virtually every year since the 1972 outbreak, western Maine has experienced PSP outbreaks, and on a less-frequent basis, New Hampshire and Massachusetts have as well. This pattern has been viewed as a direct result of Alexandrium cysts being retained in western Gulf of Maine waters once introduced there by the 1972 bloom. Between 1994 and 2004 there was virtually no toxicity in Massachusetts Bay (see figure). Significant regional-scale Alexandrium fundyense blooms occurred in both 2005 and 2006. The 2005 event was longer, extended further to the south and had higher cell concentrations and shellfish toxicities. In 2007, toxicity was restricted to sections of Eastern and Western Maine. A large, offshore bloom was documented on Georges Bank as well. In 2008, a significant regional-scale Alexandrium fundyense bloom occurred . Toxicity was particularly high in eastern Maine but also extended south to Massachusetts Bay and parts of Cape Cod. An offshore bloom of the species was also detected on Georges Bank. It is noteworthy that this bloom was predicted several months in advance based on the abundance of A. fundyense cysts in Gulf of Maine sediments (see press release).Details on these bloom events are provided in separate sections, accessed through the navigation buttons to the left. Last updated: July 24, 2009 | ||||||||||||||||||||
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