1 Descriptive Section

1.1 Indicator category

[1] “Habitat-Living”

1.2 Indicator name

Harmful Algal Blooms

Includes variable(s): Bay_of_Fundy Alexandrium, East_Gulf_of_Maine Alexandrium, Gulf_of_Maine_All Alexandrium, MA PSP, ME PSP, NH PSP, West_Gulf_of_Maine Alexandrium

1.3 Indicator brief description

These data represent annual estimated abundance of Alexandrium catanella cysts in the Gulf of Maine from 2003 to 2023.

1.4 Indicator visualization

Visualizations of the data include an annual time series plot of estimated cyst abundance, and a time series of maps depicting the spatial and temporal variability in the Gulf of Maine. Results are plotted as estimated total numbers of cells (10 to the 16th power) in Eastern Gulf of Maine (east of Penobscot Bay), Western Gulf of Maine (west of Penobscot Bay), Bay of Fundy, and entire Gulf of Maine.

## [1] "This indicator is only present in the 'NewEngland' report"

## [1] "This indicator is only present in the 'NewEngland' report"

2 SMART Attribute Section

2.1 Indicator documentation

2.1.1 Are indicators available for others to use (data downloadable)?

Yes

2.1.1.1 Where can indicators be found?

Data: https://noaa-edab.github.io/ecodata/index.html

Description: https://noaa-edab.github.io/catalog/habs.html

Technical documentation: https://noaa-edab.github.io/tech-doc/habs.html

2.1.1.2 How often are they updated? Are future updates likely?

[need sequential look at datasets for update frequency. Future requires judgement]

2.1.1.3 Who is the contact?

Moe Nelson, david.moe.nelson@noaa.gov

2.1.2 Gather indicator statistics

2.1.2.1 Units

Indicator	Units
Bay_of_Fundy Alexandrium	no Units field
East_Gulf_of_Maine Alexandrium	no Units field
Gulf_of_Maine_All Alexandrium	no Units field
MA PSP	no Units field
ME PSP	no Units field
NH PSP	no Units field
West_Gulf_of_Maine Alexandrium	no Units field

2.1.2.2 Length of time series, start and end date, periodicity

General overview: Cyst are sampled in the fall and winter months, and reported annually.

Indicator specifics:

Indicator	EPU	StartYear	EndYear	NumYears
Bay_of_Fundy Alexandrium	GOM	2003	2023	21
East_Gulf_of_Maine Alexandrium	GOM	2003	2023	21
Gulf_of_Maine_All Alexandrium	GOM	2003	2023	21
MA PSP	NE	1972	2019	48
ME PSP	NE	2005	2019	15
NH PSP	NE	2000	2019	20
West_Gulf_of_Maine Alexandrium	GOM	2003	2023	21

2.1.2.3 Spatial location, scale and extent

General overview: Results are reported for the entire Gulf of Maine, and parsed by sub-regions: Eastern Gulf of Maine (east of Penobscot Bay), Western Gulf of Maine (west of Penobscot Bay), and Bay of Fundy.

Indicator specifics:

Indicator	EPU
Bay_of_Fundy Alexandrium	GOM
East_Gulf_of_Maine Alexandrium	GOM
Gulf_of_Maine_All Alexandrium	GOM
MA PSP	NE
ME PSP	NE
NH PSP	NE
West_Gulf_of_Maine Alexandrium	GOM

2.1.2.4 Management scale: all species, FMP level, species level, can it be aggregated or separated to different scales?

[Classify by hand, note gridded data if available could be applied to different species ranges]

2.1.2.5 Uncertainty metrics

Uncertainty is captured in these variables:

character(0)

2.1.3 Are methods clearly documented to obtain source data and calculate indicators?

Yes

2.1.3.1 Can the indicator be calculated from current documentation?

Tabular data provided by Yizhen Li, NOAA/NOS NCCOS Stressor Detection and Impacts Division, HAB Forecasting Branch.

The spatial distribution and abundance of cyst cells from the annual survey are used to drive an ecosystem forecast model for the Gulf of Maine (Anderson et al. (2005), Li et al. (2009), Li et al. (2020), McGillicuddy et al. (2011)). The model also includes many other inputs of dynamic oceanographic data such as currents, temperature, and nutrients. Operational Harmful Algal Bloom forecast is served online at https://coastalscience.noaa.gov/research/stressor-impacts-mitigation/hab-forecasts/gulf-of-maine-alexandrium-catenella-predictive-models/.

2.1.3.2 Is code publicly available? up to date?

2.1.3.3 Have methods changed over time?

2.1.4 Are indicator underlying source data linked or easy to find?

Source data are NOT publicly available. Data were provided upon request by Yizhen Li. Data are also used in operational HAB forecast models, freely available to the public.

2.1.4.1 Where are source data stored?

Alexandrium cysts in sediments of the Gulf of Maine have been monitored through a cooperative effort of NOAA, WHOI, and other partners for over twenty years. Sampling methods are described in Anderson et al. (2005). In the annual survey cruises, samples are obtained with a Craib corer, and Alexandrium cysts are counted from the top 1- cm of sediment layer. Results are extrapolated to estimate overall cyst abundance in the eastern, western, and entire Gulf of Maine.Results are reported as estimated total numbers of cells (10 to the 16th power) in Eastern Gulf of Maine (east of Penobscot Bay), Western Gulf of Maine (west of Penobscot Bay), Bay of Fundy (2003-2013 only), and entire Gulf of Maine.

2.1.4.2 How/by whom are source data updated? Are future updates likely?

Moe Nelson david.moe.nelson@noaa.gov

[likelihood of source data updates requires judgement, enter by hand]

2.1.4.3 How often are they updated?

[Update by hand, look for source, may require judgement]

2.2 Indicator analysis/testing or history of use

2.2.1 What decision or advice processes are the indicators currently used in?

2.2.2 What implications of the indicators are currently listed?

The annual fall surveys of Alexandrium cyst distribution and abundance in the Gulf of Maine provide data needed to predict bloom events in the following year. Other key variables in the predictive models include currents, nutrients, temperature, and salinity dynamics at multiple spatial and temporal scales [7]. After strong cyst deposition events in 2005 and 2009, the time series suggest lower overall cyst abundance through 2023. The cyst abundance in the 2023 survey was relatively low, and a low to moderate bloom year was predicted for 2024 (Li et al. 2024). Bloom events and shellfishery closures usually occur somewhere in any given year. Economic impacts to inshore shellfisheries (mussels, softshell clams, quahogs) can be substantial [8]. Impacts to offshore shellfisheries can occur as well, for example surf clam and ocean quahog on Georges Bank 1988-1990 [9].

2.2.3 Do target, limit, or threshold values already exist for the indicator?

2.2.4 Have the indicators been tested to ensure they respond proportionally to a change in the underlying process?

2.2.5 Are the indicators sensitive to a small change in the process, or what is the threshold of change that is detectable?

Unknown

2.2.6 Is there a time lag between the process change and the indicator change? How long?