Monday, April 11, 2016

What is a stock assessment? Part I


Assessing in style
           Stock assessments are an important part of the way we manage fisheries in the U.S. A lot goes into a single stock assessment, and they can be quite daunting to navigate. However, when you break them down into their component parts they really aren’t so bad! In this post we will begin to explore stock assessments by introducing the concept and talking a bit about the process involved with stock assessments in Federal waters (*in Florida, marine waters past 3 miles offshore in the Atlantic and past 9 miles offshore in the Gulf of Mexico are governed by the Federal government through NOAA’s Fisheries branch, and waters inshore of that are governed by the State through the Florida Fish and Wildlife Conservation Commission; they also use stock assessments, and we will tackle their management process in a future post).

Background: what is a stock assessment?

At its heart, a stock assessment is simply what it says: a project aimed at assessing a stock of fish. The term “stock” simply refers to a unit of fish that is being managed. The unit might be distinguished based on biology or fishing practices. For example, in the state of Florida our fish species are often divided into Atlantic and Gulf of Mexico stocks because few fish travel between the two bodies of water, so we consider them separately. A stock assessment pulls together all of the available information on that stock, including biology and information about fishing, to try to figure out both what is going on with the stock at present (Is it overfished? Is it doing just fine?) and to predict what will happen in the future (What about 10 years from now? Can we keep fishing the same way?).

Grouper are one example of species
assessed using the SEDAR process

Stock Assessments in the South: the SEDAR process

SEDAR (short for the “Southeast Data, Assessment, and Review”) refers to the way Federal stock assessments are conducted in the Southeastern U.S. The process consists of three workshops: the Data Workshop, the Assessment process, and the Review Workshop. During the Data Workshop, fisheries scientists pull together all of the data, or information, that will be needed for the stock assessment. Next, researchers use this information to create the stock assessment models during the Assessment process (*we will talk more about models soon). Finally, a group of different experts review everything during the Review Workshop. The completed assessment (including all three reports from the workshops) are then sent to the appropriate Fisheries Management Council’s Scientific and Statistical Committee to be accepted as appropriate for management. The Committee then uses the information in the assessment to make management recommendations, which go to the Fisheries Management Council (in Florida, this would be either the Gulf ofMexico Fishery Management Council or the South Atlantic Fishery ManagementCouncil). The SEDAR process is certainly complex and involved, but it helps ensure that the stock assessments are of the highest quality and therefore that the management recommendations we get out of them are the best possible.

Stock Rebuilding Targets: Biological Reference Points

            If a stock has been assessed as overfished (meaning that too many fish were caught in the past), the Sustainable Fisheries Act (*a National Act passed by Congress) mandates that managers create a “rebuilding plan” for the stock to get it back to sustainable levels. To do this, managers have to aim for a target, or “biological reference point”, that lets them know that the stock has returned to sustainable levels. There are many different types of reference points, and we will explore them in detail in another post.

Next time: what all goes into a stock assessment? 

*Want to learn more? Check out these handy resources:

NOAA Assessment 101


1 comment:

  1. The content is very broad and it is getting more importance from the readers. The listener can get full details from the article .