General Information

Event name: US-20-003
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 39-186.1μg/100g)
Associated syndrome: PSP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector):
Report the outcome of a monitoring programme: Yes (Connecticut Department of Agriculture Bureau of Aquaculture)
Event occurred before in this location: Yes (There was a PSP closure in Mumford Cove in 2020. CT has two areas with known Alexandrium catenella cyst beds - Mumford Cove and Palmer Cove in the town of Groton. Mumford Cove previously had PSP closures in 1985 and 1992. Palmer Cover had PSP closures in 1992 and 2003. Therefore, this is the first year that CT had a PSP closure since 2003, and the highest saxitoxin concentrations in Mumford Cove since 1985.)
Individuals to contact: VAN GULICK, Emily

Location & Date

[View larger map]
Location: Latitude: , Longitude:
General location information: Mumford Cove, Groton, CT
HAB Area code(s): US-07
Additional location information: No visible blooms were reported or observed by staff members collecting samples. However, there was a Alexandrium catenella bloom for all of April 2020, noted by the continued detection of high levels of saxitoxin in sentinel blue mussels.
Bloom event dates (yyyy/mm/dd): Start: 2020-04-06, End: 2020-05-12
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Earliest A. cat bloom and closure in CT


Causative organism known: Yes
Causative Species/Genus: Alexandrium catenella (370 cells/L)
A limited number of phytoplankton samples were collected due to staff restrictions related to COVID-19; therefore, this is not the bloom max but rather the max cell concentration detected. The focus switched to toxin testing once bloom detected.
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information: The bloom occurred ~8℃, which is colder than optimal bloom conditions reported for A. catenella in the area. Past closures in Mumford Cove occurred in May, but environmental data was not recorded during these historic events (1985, 1992). Palmer Cove PSP closures have occurred in early June, and the 2003 bloom was occurring ~15℃. It will be interesting to see if the blooms continue to follow these different temperature patterns in the future, given that the coves are located next to one another (but are not interconnected in anyway).
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity:
Nutrient information:
Temperature Range During Event: Max: 8.6 °C, Min: 8.2 °C
Salinity Range During Event: Max: 29.4, Min: 28.5
Bloom location in the water column:
In situ
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Blue mussels Saxitoxins 186.1μg/100g Bioassay-Mouse
Kit used: Yes Type of kit used: Scotia
Additional information: Blue mussel samples collected on 4/6, 4/20 and 4/28 were all positive by scotia rapid test kit. Extracts were saved and subsequently positive by mouse bioassay.
Economic losses: Mumford Cove is a recreational area; therefore, no commercial economic loss. However, Mumford Cove is a popular recreational shellfishing location. The area closed 1 month earlier than it would have seasonally, so some minor loss from daily permits.
Management decision: The area was closed on 3/25 due to rainfall >1". Saxitoxin was detected above the regulatory limit on 4/6 as part of the necessary reopening testing; therefore, the area remained closed for all of April.
Additional harmful effect information: The area officially closed for the spring on 3/25 and did not reopen again until November 2020.
Created at 10:05 on 19 Apr 2021