Catch studies indicate more red snapper since 1992.In 1992, tightened regulations on Atlantic red snapper were enacted, including a recreational two-fish bag limit and a 20-inch minimum total length. Have these changes been effective? Are red snapper stocks still declining? The statistical measure of catch per unit data gives us insight.
Catch per unit of effort (CPUE CPUE Catch Per Unit Effort (fishing industry) ) is a simple and extremely useful index of stock abundance. Often it is used to diagnose unsustainable fishing of a species.
It is a relative index of abundance, used to indicate directional changes (such as increases or decreases).
The "catch" can be expressed as the total weight of an entire catch or that of a certain species. Likewise, numbers of fish caught could be used in this index, as well. The "unit effort" has a time component, either by hour or per "angler trip." Included in effort is an index of gear used, for example, number of hooks in the water, gillnet gill·net
tr.v. gill·net·ted, gill·net·ting, gill·nets
To catch (fish) by means of a gill net. sets, vessels, or simply per angler. Careful attention must be given to the units when comparing CPUE datasets.
The SEDAR SEDAR System for Electronic Document Analysis and Retrieval
SEDAR Southeast Data, Assessment, and Review 15 document--the scientific basis of the changes currently being considered by NOAA and its South Atlantic Fishery Management Council--provides CPUE information on red snapper harvesting from three distinct groups: commercial fishermen, headboats (for hire vessels that generally charge a fee per angler, typically accommodating 2060 passengers), and recreational fishers (SEDAR 15 SAR (Segmentation And Reassembly) The protocol that converts data to cells for transmission over an ATM network. It is the lower part of the ATM Adaption Layer (AAL), which is responsible for the entire operation. See AAL.
SAR - segmentation and reassembly 1 SECTION II Pt 5).
In general, the data collected from the three user groups show an increase in CPUE indices and suggest the stocks have been increasing since the regulations were enacted in 1992. (See figure.)
The commercial CPUE (expressed in pounds per hook-hour), headboat CPUE (in number per hook-hr) and recreational CPUE (in number per angler-trip) all show a positive slope. The three datasets, collected from three different groups using different techniques and units, all show the same trend--an increase in CPUE, and thus, one can surmise that there have been the associated increases in red snapper stocks.
The enhanced regulations of 1992 seem to be working to increase red snapper stocks, but not deemed fast enough according to goals set by federal authorities based on estimates of what abundance may have been in the 194582 period.
We conclude, however, that the CPUE data, coupled with the researchers' other data over the past quarter-century, point to a growing stock.
Raymond E. Waldner
Ph.D., Professor of Biology
Ph.D., Associate Professor of Biology
Palm Beach Atlantic University Palm Beach Atlantic University (PBA) is a comprehensive evangelical Christian university with a core emphasis on character formation by integrating a Christian worldview with the liberal arts and selected professional studies.