Definition and Importance:
Commercial fish biomass refers to the total mass of key commercial fish species that belong to the grouper and snapper families, and are the most highly targeted for fisheries in the MAR. High commercial fish biomass indicates a healthy reef that can support some fishing activities without depleting fish stocks. Likewise, low commercial fish biomass indicates that the ecosystem is lacking in these key predators, their ecological functions, and the ability to sustain local fisheries. It is also an indicator of the overall health of the marine ecosystem, as these species play critical roles in food webs, it offers an indication of stock status, fishing pressure, habitat conditions, and recruitment success.

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How Do We Measure it?
The Atlantic and Gulf Rapid Reef Assessment AGRRA protocol measures commercial fish biomass using fish belt transects.  Divers swim deploying a transect line, recording the species, size, and number of fish observed within a set area (e.g., 30 meters long by 2 meters wide, with 10 transects per site). The collected data is then used to calculate biomass using established length-weight relationships for each species. This standardized approach allows for consistent monitoring of commercial fish populations across different reef areas.