1 Descriptive Section

1.1 Indicator category

[1] “Fish”

1.2 Indicator name

NE Shelf Functional Trait Indicators

Includes variable(s): FALL-age_maturity, FALL-fecundity, FALL-k, FALL-l_inf, FALL-length_maturity, FALL-max_obs_length, FALL-offspring_size, FALL-PC1, FALL-PC2, FALL-PC3, FALL-trophic_level, SPRING-age_maturity, SPRING-fecundity, SPRING-k, SPRING-l_inf, SPRING-length_maturity, SPRING-max_obs_length, SPRING-offspring_size, SPRING-PC1, SPRING-PC2, SPRING-PC3, SPRING-trophic_level

1.3 Indicator brief description

These data represent estimates of trait distributions for key functional traits amongst finfish species at each EPU on the Northeast Continental Shelf.

1.4 Indicator visualization

SOE_Submission_results.docx I’m happy to share the code used to produce these figures from the data linked above.

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/finfish_traits.html

Technical documentation: https://noaa-edab.github.io/tech-doc/finfish_traits.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?

Bart DiFiore (bdifiore@gmri.org)

2.1.2 Gather indicator statistics

2.1.2.1 Units

Indicator	Units
FALL-age_maturity	years
FALL-fecundity	number of offspring per mature female
FALL-k	1/years
FALL-l_inf	cm
FALL-length_maturity	cm
FALL-max_obs_length	cm
FALL-offspring_size	mm
FALL-PC1	unitless
FALL-PC2	unitless
FALL-PC3	unitless
FALL-trophic_level	unitless
SPRING-age_maturity	years
SPRING-fecundity	number of offspring per mature female
SPRING-k	1/years
SPRING-l_inf	cm
SPRING-length_maturity	cm
SPRING-max_obs_length	cm
SPRING-offspring_size	mm
SPRING-PC1	unitless
SPRING-PC2	unitless
SPRING-PC3	unitless
SPRING-trophic_level	unitless

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

General overview: 1963-2023, Spring (January-June) & Fall (July-December)

Indicator specifics:

Indicator	EPU	StartYear	EndYear	NumYears	MissingYears
FALL-age_maturity	GB	1963	2024	61	1
FALL-age_maturity	GOM	1963	2024	61	1
FALL-age_maturity	MAB	1963	2024	60	2
FALL-age_maturity	NEshelf	1963	2024	61	1
FALL-age_maturity	SS	1963	2024	61	1
FALL-fecundity	GB	1963	2024	61	1
FALL-fecundity	GOM	1963	2024	61	1
FALL-fecundity	MAB	1963	2024	60	2
FALL-fecundity	NEshelf	1963	2024	61	1
FALL-fecundity	SS	1963	2024	61	1
FALL-k	GB	1963	2024	61	1
FALL-k	GOM	1963	2024	61	1
FALL-k	MAB	1963	2024	60	2
FALL-k	NEshelf	1963	2024	61	1
FALL-k	SS	1963	2024	61	1
FALL-l_inf	GB	1963	2024	61	1
FALL-l_inf	GOM	1963	2024	61	1
FALL-l_inf	MAB	1963	2024	60	2
FALL-l_inf	NEshelf	1963	2024	61	1
FALL-l_inf	SS	1963	2024	61	1
FALL-length_maturity	GB	1963	2024	61	1
FALL-length_maturity	GOM	1963	2024	61	1
FALL-length_maturity	MAB	1963	2024	60	2
FALL-length_maturity	NEshelf	1963	2024	61	1
FALL-length_maturity	SS	1963	2024	61	1
FALL-max_obs_length	GB	1963	2024	61	1
FALL-max_obs_length	GOM	1963	2024	61	1
FALL-max_obs_length	MAB	1963	2024	60	2
FALL-max_obs_length	NEshelf	1963	2024	61	1
FALL-max_obs_length	SS	1963	2024	61	1
FALL-offspring_size	GB	1963	2024	61	1
FALL-offspring_size	GOM	1963	2024	61	1
FALL-offspring_size	MAB	1963	2024	60	2
FALL-offspring_size	NEshelf	1963	2024	61	1
FALL-offspring_size	SS	1963	2024	61	1
FALL-PC1	GB	1963	2024	61	1
FALL-PC1	GOM	1963	2024	61	1
FALL-PC1	MAB	1963	2024	60	2
FALL-PC1	NEshelf	1963	2024	61	1
FALL-PC1	SS	1963	2024	61	1
FALL-PC2	GB	1963	2024	61	1
FALL-PC2	GOM	1963	2024	61	1
FALL-PC2	MAB	1963	2024	60	2
FALL-PC2	NEshelf	1963	2024	61	1
FALL-PC2	SS	1963	2024	61	1
FALL-PC3	GB	1963	2024	61	1
FALL-PC3	GOM	1963	2024	61	1
FALL-PC3	MAB	1963	2024	60	2
FALL-PC3	NEshelf	1963	2024	61	1
FALL-PC3	SS	1963	2024	61	1
FALL-trophic_level	GB	1963	2024	61	1
FALL-trophic_level	GOM	1963	2024	61	1
FALL-trophic_level	MAB	1963	2024	60	2
FALL-trophic_level	NEshelf	1963	2024	61	1
FALL-trophic_level	SS	1963	2024	61	1
SPRING-age_maturity	GB	1968	2024	56	1
SPRING-age_maturity	GOM	1968	2024	56	1
SPRING-age_maturity	MAB	1968	2024	56	1
SPRING-age_maturity	NEshelf	1968	2024	57	0
SPRING-age_maturity	SS	1968	2024	56	1
SPRING-fecundity	GB	1968	2024	56	1
SPRING-fecundity	GOM	1968	2024	56	1
SPRING-fecundity	MAB	1968	2024	56	1
SPRING-fecundity	NEshelf	1968	2024	57	0
SPRING-fecundity	SS	1968	2024	56	1
SPRING-k	GB	1968	2024	56	1
SPRING-k	GOM	1968	2024	56	1
SPRING-k	MAB	1968	2024	56	1
SPRING-k	NEshelf	1968	2024	57	0
SPRING-k	SS	1968	2024	56	1
SPRING-l_inf	GB	1968	2024	56	1
SPRING-l_inf	GOM	1968	2024	56	1
SPRING-l_inf	MAB	1968	2024	56	1
SPRING-l_inf	NEshelf	1968	2024	57	0
SPRING-l_inf	SS	1968	2024	56	1
SPRING-length_maturity	GB	1968	2024	56	1
SPRING-length_maturity	GOM	1968	2024	56	1
SPRING-length_maturity	MAB	1968	2024	56	1
SPRING-length_maturity	NEshelf	1968	2024	57	0
SPRING-length_maturity	SS	1968	2024	56	1
SPRING-max_obs_length	GB	1968	2024	56	1
SPRING-max_obs_length	GOM	1968	2024	56	1
SPRING-max_obs_length	MAB	1968	2024	56	1
SPRING-max_obs_length	NEshelf	1968	2024	57	0
SPRING-max_obs_length	SS	1968	2024	56	1
SPRING-offspring_size	GB	1968	2024	56	1
SPRING-offspring_size	GOM	1968	2024	56	1
SPRING-offspring_size	MAB	1968	2024	56	1
SPRING-offspring_size	NEshelf	1968	2024	57	0
SPRING-offspring_size	SS	1968	2024	56	1
SPRING-PC1	GB	1968	2024	56	1
SPRING-PC1	GOM	1968	2024	56	1
SPRING-PC1	MAB	1968	2024	56	1
SPRING-PC1	NEshelf	1968	2024	57	0
SPRING-PC1	SS	1968	2024	56	1
SPRING-PC2	GB	1968	2024	56	1
SPRING-PC2	GOM	1968	2024	56	1
SPRING-PC2	MAB	1968	2024	56	1
SPRING-PC2	NEshelf	1968	2024	57	0
SPRING-PC2	SS	1968	2024	56	1
SPRING-PC3	GB	1968	2024	56	1
SPRING-PC3	GOM	1968	2024	56	1
SPRING-PC3	MAB	1968	2024	56	1
SPRING-PC3	NEshelf	1968	2024	57	0
SPRING-PC3	SS	1968	2024	56	1
SPRING-trophic_level	GB	1968	2024	56	1
SPRING-trophic_level	GOM	1968	2024	56	1
SPRING-trophic_level	MAB	1968	2024	56	1
SPRING-trophic_level	NEshelf	1968	2024	57	0
SPRING-trophic_level	SS	1968	2024	56	1

2.1.2.3 Spatial location, scale and extent

General overview: By EPU and full shelf

Indicator specifics:

Indicator	EPU
FALL-age_maturity	GB
FALL-age_maturity	GOM
FALL-age_maturity	MAB
FALL-age_maturity	NEshelf
FALL-age_maturity	SS
FALL-fecundity	GB
FALL-fecundity	GOM
FALL-fecundity	MAB
FALL-fecundity	NEshelf
FALL-fecundity	SS
FALL-k	GB
FALL-k	GOM
FALL-k	MAB
FALL-k	NEshelf
FALL-k	SS
FALL-l_inf	GB
FALL-l_inf	GOM
FALL-l_inf	MAB
FALL-l_inf	NEshelf
FALL-l_inf	SS
FALL-length_maturity	GB
FALL-length_maturity	GOM
FALL-length_maturity	MAB
FALL-length_maturity	NEshelf
FALL-length_maturity	SS
FALL-max_obs_length	GB
FALL-max_obs_length	GOM
FALL-max_obs_length	MAB
FALL-max_obs_length	NEshelf
FALL-max_obs_length	SS
FALL-offspring_size	GB
FALL-offspring_size	GOM
FALL-offspring_size	MAB
FALL-offspring_size	NEshelf
FALL-offspring_size	SS
FALL-PC1	GB
FALL-PC1	GOM
FALL-PC1	MAB
FALL-PC1	NEshelf
FALL-PC1	SS
FALL-PC2	GB
FALL-PC2	GOM
FALL-PC2	MAB
FALL-PC2	NEshelf
FALL-PC2	SS
FALL-PC3	GB
FALL-PC3	GOM
FALL-PC3	MAB
FALL-PC3	NEshelf
FALL-PC3	SS
FALL-trophic_level	GB
FALL-trophic_level	GOM
FALL-trophic_level	MAB
FALL-trophic_level	NEshelf
FALL-trophic_level	SS
SPRING-age_maturity	GB
SPRING-age_maturity	GOM
SPRING-age_maturity	MAB
SPRING-age_maturity	NEshelf
SPRING-age_maturity	SS
SPRING-fecundity	GB
SPRING-fecundity	GOM
SPRING-fecundity	MAB
SPRING-fecundity	NEshelf
SPRING-fecundity	SS
SPRING-k	GB
SPRING-k	GOM
SPRING-k	MAB
SPRING-k	NEshelf
SPRING-k	SS
SPRING-l_inf	GB
SPRING-l_inf	GOM
SPRING-l_inf	MAB
SPRING-l_inf	NEshelf
SPRING-l_inf	SS
SPRING-length_maturity	GB
SPRING-length_maturity	GOM
SPRING-length_maturity	MAB
SPRING-length_maturity	NEshelf
SPRING-length_maturity	SS
SPRING-max_obs_length	GB
SPRING-max_obs_length	GOM
SPRING-max_obs_length	MAB
SPRING-max_obs_length	NEshelf
SPRING-max_obs_length	SS
SPRING-offspring_size	GB
SPRING-offspring_size	GOM
SPRING-offspring_size	MAB
SPRING-offspring_size	NEshelf
SPRING-offspring_size	SS
SPRING-PC1	GB
SPRING-PC1	GOM
SPRING-PC1	MAB
SPRING-PC1	NEshelf
SPRING-PC1	SS
SPRING-PC2	GB
SPRING-PC2	GOM
SPRING-PC2	MAB
SPRING-PC2	NEshelf
SPRING-PC2	SS
SPRING-PC3	GB
SPRING-PC3	GOM
SPRING-PC3	MAB
SPRING-PC3	NEshelf
SPRING-PC3	SS
SPRING-trophic_level	GB
SPRING-trophic_level	GOM
SPRING-trophic_level	MAB
SPRING-trophic_level	NEshelf
SPRING-trophic_level	SS

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?

Here, we present indices for 8 functional traits and three aggregate trait ordinations. To better understand the long-term linear change in these indicators, we fit linear mixed effects models. Specifically, at the EPU scale we estimated the linear change in the response (e.g. PCA1, PCA2, or PCA3) with time in each season in each EPU . We include year as a random intercept effect to account for systematic annual variation across EPU’s. For visualization purposes we include the long-term linear trend if the 95% confidence intervals on the slope estimate do not include zero. Principal Component Analysis of traits Many traits represent similar variation in the community. For instance, maximum observed body size and asymptotic body size (from the VB growth equation) both represent similar trait indices. To further reduce the dimensionality across traits, we conducted a principal component analysis (PCA) of the trait database. The first principal component (PCA1) explained 61.5% of the variation, while the second component (PCA2) explained 19.6% of the variation. Traits such as VB growth parameter k, length at maturity, age at maturity, maximum observed length, and VB growth parameter linf all loaded strongly on PCA1. Following, McKeon et al. (2024) we consider this PCA axis as an indicator for finfish “Pace of Life”, with higher values on this axis representing faster growth and small maximum body size. Similarly, we consider the second axis as an indicator of “Fecundity”, with higher values on the axis reflecting lower reproductive investment (smaller offspring, higher fecundity). Estimating trait distributions To generate a functional trait index, we then combined our trait database with observations of the finfish community using a community weighted mean (CWM) approach (e.g. Lavorel et al. (2008), Frainer et al. (2017)). Specifically, we follow Lavorel et al. (2008), and estimate the CWM for each trait j as \[CWM_j = \frac{\sum_{i=1}^nb_it_{ij}}{\sum_{i=1}^nb_i}\] where \(b_i\) is the biomass (kg) of species \(i\), \(t_{ij}\) is the value of trait \(j\) for species \(i\), and \(n\) is the total number of species captured. The units of \(CWM_j\) depend on the trait value. For instance, the units of the CWM length at maturity are cm. The community weighted mean can be estimated at different spatial or temporal scales. Here we estimate the CWM for each trait at the scale of the NE Shelf, where bi is the biomass (kg) of species i captured across all tows in a year and season, or similarly at the EPU scale, where bi is the biomass (kg) of species i captured across each EPU in each year and season. All other data preparation and processing is standard to the trawl survey data prep, including species-specific vessel corrections, etc.

2.1.3.2 Is code publicly available? up to date?

GitHub code repository linked

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 publicly available.

2.1.4.1 Where are source data stored?

Currently, the version of the NEFSC Trawl Survey used to generate the community weighted mean trait values is from https://github.com/NOAA-EDAB/data-requests/tree/main/EwE-menhaden-AndreBuchheister. However, any version of the trawl survey data that has corrected estimates of biomass by species at the tow scale could be used to update/recreate the index. The trait values for each species can be found at https://github.com/bartdifiore/Fish-Functional-Traits/blob/main/Data/Derived/trait_database.csv and the PCA ordinations of these traits can be found at https://github.com/bartdifiore/Fish-Functional-Traits/blob/main/Data/Derived/pca_variables.csv. I have included in this submission the derived CWM trait database that can be directly used to create all figures etc. Development of the Trait Database To develop the trait database we utilized two primary sources: Beukhof et al. (2019) and James T. Thorson et al. (2023) FishLife database. Both data sources are based on FishBase (Froese and Pauly 2019), however provide different levels of detail. Specifically, we queried the Beukhof et al. (2019) database for finfish species encountered in the NE Shelf trawl survey. We utilized values from Beukhof et al. (2019) that were species-specific (e.g. not estimated based on averages of traits across other species of the same genus, family, class, order). For remaining species encountered on the NE Shelf, we queried the FishLife database. The FishLife database used a modeling approach to impute trait values for all fish species in FishBase based on taxonomic relatedness. Thus, if a trait for a particular species was unknown, the model generated a prediction for that trait based on taxonomic relatedness via a structural equation model.

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

Bart DiFiore bdifiore@gmri.org

[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?

Functional traits, such as length at maturity, asymptotic body size, or fecundity, offer a means to synthesize change across complex, diverse communities while avoiding the pitfalls of examining change in any given species. In general, ecological theory predicts that if many species play similar roles in an ecosystem, known as high functional redundancy, then the loss of any one species will be compensated by the prevalence of functionally similar species, allowing for greater stability and resilience at the ecosystem level. Therefore, monitoring changes in functional trait distributions can provide a means of assessing ecosystem-scale resilience. Here, we compiled eight key functional traits and three aggregate trait ordinations for ~388 finfish species encountered in the NEFSC trawl survey. We then estimated the prevalence of each trait for each season, year, and EPU, using a community-weighed mean approach. Finally, we used regression-based approaches to explore long-term temporal shifts in functional trait distributions.

2.2.2 What implications of the indicators are currently listed?

In general, there appears to be equivocal evidence for functional redundancy in traits at both the scale of the NE Shelf and within particular EPU’s. For instance, for trait ordination axes related to the pace of life and fecundity, there was stability in trait distributions for species captured during the fall survey. However, in the spring survey there was evidence for long-term shifts towards slower life history strategies (larger body size, lower fecundity, fewer offspring). At the EPU scale, there was little evidence for long-term linear trends in trait distributions in the Gulf of Maine and Scotian Shelf finfish communities, suggesting a high level of functional redundancy and stability in the face of dramatic shifts in oceanographic conditions (e.g. increasing temperatures) and other anthropogenic impacts. Conversely, there was evidence for long term change in trait distributions in the mid-Atlantic Bight and Georges Bank. For instance, the fall finfish community on George’s Bank and the spring finfish community in the mid-Atlantic Bight are both showing long-term shifts towards slower life history strategies with lower fecundity. These changes suggest that more research across the finfish community in these regions is needed to understand the ecological and economic ramifications of such change.

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?