Stock Assessment: Atlantic Bluefish (Mock Data)
Geographic Area: U.S. East Coast
Executive Summary & Stock Status
This dashboard provides the high-level summary of the assessment, corresponding to the report's Executive Summary (1.0) and Stock Status (5.3) sections. It provides the immediate answers on stock health and management advice.
Stock Status
Healthy
(B_current / B_MSY = 0.90)
Fishing Status
Not Overfishing
(F_current / F_MSY = 0.88)
Recommended ACL
42,000 mt
(To achieve rebuilding target)
Stock Status (Kobe Plot)
This plot (Report Section 5.3) shows the historical path of the stock. The goal is to be in the bottom-right quadrant (green), which indicates a healthy stock that is not experiencing overfishing.
Catch Projections (3-Year)
These projections (Report Section 5.4) show the likely stock biomass (SSB) under different future fishing scenarios. The recommended catch (ACL) is based on the 'Target F' scenario.
Historical Trends & Data Sources
This section allows for a deep exploration of the data used in the assessment, corresponding to the report's Data Sources (3.0) and Population Estimates (5.2) sections. Use the tabs below to switch between model-estimated population trends and the raw data that informs the model.
Spawning Stock Biomass (SSB)
This chart (Report Section 5.2) shows the model's estimate of the mature female biomass over time, compared to the target (B_MSY) and limit (B_Threshold) reference points.
Fishing Mortality (F)
This chart (Report Section 5.2) shows the model's estimate of the fishing mortality rate over time, compared to the target (F_MSY) and limit (F_Threshold) reference points.
Recruitment (Age 1 Fish)
This chart (Report Section 5.2) shows the model's estimate of the number of new fish (recruits) entering the fishery each year. High variability is common.
Total Catch (Report Section 3.1, 3.2)
This chart shows the total catch removed by commercial and recreational fleets. This data is a primary input for the assessment model.
Survey Indices (Report Section 3.3)
Fishery-independent surveys provide an index of relative abundance. The model is "fit" to these trends to estimate overall biomass.
Biological Data: Age Composition (Report Section 3.4)
This chart shows the proportion of fish at different ages in a representative year. A lack of older fish can be a sign of high fishing mortality.
Assessment Model & Methods
This section details the technical aspects of the assessment, corresponding to the report's Model & Methods (4.0), Model Fit (5.1), and Uncertainty (6.2) sections. It describes the model used and shows diagnostic plots to evaluate its performance.
4.1 Model Choice
A Statistical Catch-at-Age (SCAA) model (e.g., ASAP) was used. This model reconstructs the population's history by synthesizing information from total catch, indices of abundance, and age/length composition data.
4.3 Biological Reference Points (BRPs)
BRPs are benchmarks used to assess stock status.
• B_MSY (50,000 mt): Spawning Stock Biomass that produces Maximum Sustainable Yield (MSY).
• F_MSY (0.25): Fishing Mortality rate that produces MSY.
• The stock is 'Overfished' if B < 0.5 * B_MSY.
• 'Overfishing' occurs if F > F_MSY.
Model Fit to Survey (Report Section 5.1)
This plot shows how well the model's predicted abundance (line) matches the observed survey data (points). A good fit means the line tracks the points well.
Uncertainty: Retrospective Analysis (Report Section 6.2)
This analysis checks for model bias by re-running the assessment, removing one year of data at a time. If the lines (estimates) consistently shift in one direction (a "retrospective pattern"), the model may be biased.
Management & Discussion
This section provides the formal management advice and discusses the assessment context, corresponding to the report's Introduction (2.0), Discussion (6.0), and Management Recommendations (7.0) sections.
7.1 Stock Status Determination
Based on this assessment, the Atlantic Bluefish stock is not overfished and overfishing is not occurring.
7.2 Catch Advice
To maintain the stock at its target level (B_MSY) and prevent overfishing, the working group recommends a Total Allowable Catch (TAC) of 42,000 mt for the next two fishing years. This is based on the F_MSY projection scenario (see Dashboard).
7.3 Future Research Needs
- Improve understanding of recreational discard mortality.
- Investigate the impact of water temperature on recruitment.
- Expand age sampling in the commercial fishery.
2.1 The Stock & 2.3 Fishery
Atlantic Bluefish (Pomatomus saltatrix) is a migratory species managed as a single stock from Maine to Florida. It is targeted by both commercial and recreational fisheries. The recreational fishery, operating via private boats and for-hire vessels, accounts for approximately 80% of the total catch in most years.
6.1 Interpretation & 6.3 Ecosystem
The current healthy status is the result of reduced fishing mortality since the early 2000s, which allowed the stock to rebuild. However, recruitment has been below average for the last five years. It is noted that Bluefish are a key predator, and their abundance may be linked to the availability of key forage species like Atlantic Mackerel and Menhaden.