Discord and Discards

How known flaws in recreational data are adding up to a big headache for recreational anglers.

By Brad Gentner
CCA Southeast Fisheries Director

For the past 15 years or so, anglers in the South Atlantic have grappled with extraordinarily short red snapper seasons despite the emergence of a wildly recovering stock. For many years, legitimate concerns with the health of the red snapper population necessitated reduced fishing pressure, but now the problem is, quite literally, too many fish. After an unprecedented run of spawning success, there are now red snapper just about everywhere in the South Atlantic and anglers are encountering them almost every time they drop a line offshore. And therein lies the problem.

Even though anglers are not allowed to keep a red snapper 364 days a year, some of the ones they catch and throw back out of season don’t survive. How NOAA Fisheries calculates that bycatch mortality alone is enough to cause massive problems. Federal managers say the level of bycatch mortality caused by anglers fishing for other things throughout the year takes up the entire allocation of red snapper that would otherwise be available for harvest. The situation is especially alarming as NOAA Fisheries recently declared that red snapper is no longer overfished and overfishing is not occurring. While that should be a cause for celebration, in this case it isn’t because that means the situation is not going to improve. A one or two-day season is about as good as it will ever be under the current federal management regime, and NOAA says it is all due to bycatch mortality from astronomical levels of recreational fishing pressure.

But how legitimate are these assumptions? Is this a real crisis or a paper crisis? Discard estimates from the Marine Recreational Information Program (MRIP) are known to be plagued with bias issues, but they are applied in the management process as gospel where they are used to draw illogical conclusions. Recently we have seen high discard estimates coupled with high recruitment in the South Atlantic red snapper fishery. A rapidly growing stock should have high discards, but that should not result in very short seasons, particularly when the stock is no longer overfished and overfishing is not occurring. If the discards were so high, how did the stock recover so broadly and so fast?

In a related but different case with black seabass, discards of juvenile fish in the shore mode are astronomically high, yet the management advice is that recruitment has failed and the stock is either badly overfished or has moved north to cooler waters. Both conclusions by National Marine Fishery Service (NMFS) – high discards of juvenile fish AND recruitment failure -– is a dichotomy that simply can’t be true. The simplest conclusion is that the discard data is horribly inflated.

MRIP Discard Estimates

There has been speculation that the NMFS was taking discards per unit effort (DPUE) from directed red snapper trips and applying a separate effort domain (all recreational trips) to expand those estimates to MRIP discards. That is not the case. Currently, NMFS applies the correct effort domain to the correct DPUE domain. So why do we believe discards are incorrectly high? Several explanations emerge: digit bias, exaggeration bias and biases in the Fishing Effort Survey (FES).

The general formula for total discards is the mean DPUE by domain multiplied by the mean effort by the same domain from the FES. It is well known that DPUE (B2 catch) is plagued by both digit bias and exaggeration. Digit bias in surveys refers to the tendency of survey respondents to favor certain digits, particularly 0 and 5, when reporting numerical values. While harvest is viewed by the interviewer, discards are strictly self-reported. That is, say an angler caught four fish and released them alive, they are more likely to round up to five. Closely related to this rounding phenomenon is exaggeration bias.

Exaggeration bias can take many forms and the relevant forms here include:

• Social Desirability Bias: This occurs when respondents answer in a way they believe will be viewed favorably by others or to conform to societal norms. This can lead people to overreport “good” behaviors (like exercising regularly or donating to charity or releasing fish alive) and underreport “bad” or undesirable behaviors (like unhealthy habits or violating the law or releasing fish dead). One can see how anglers would be boastful about their release behavior because it fits a social construct.
• Self-Deceptive Enhancement: A component of social desirability bias where a respondent genuinely believes they possess a particular positive quality and answers questions in a way that supports this embellished self-perception, even if it’s an overstatement. This is the classic fisher exaggeration. This angler stereotype is well known and is included in cultural humor and memes. It is typical for anglers to exaggerate the total numbers caught or the size of fish released. Most quit counting in single digits at a very low number and start counting or remembering in chunks of fives and tens. It is not hard to see that a big exaggeration in an angler’s response would be blown up into a massive amount of estimated discards when multiplied by the total effort.
• Impression Management: Another component is social desirability bias, where individuals consciously and deliberately provide false or exaggerated answers to create a positive image for themselves. This is very similar to the above response and is also heavily at play here. Fishermen have egos supported by their angling prowess.

Studies within the MRIP program have indicated that digit bias and exaggeration bias are indeed issues in the discard estimates. If you have ever observed an MRIP creel survey interview, you would immediately see both types of bias. NMFS’ response has been to assume that the upward digit and exaggeration biases are balanced out by downward digit and exaggeration bias, but this has never been validated. As an angler and a recreational fisheries survey designer, my experience is exaggeration and digit bias are predominantly in an upwards direction.

Having identified biases that are likely increasing mean DPUE estimates, the discussion then shifts to the quality of the effort estimates used to expand the DPUE estimates to a total discards estimate. For those unfamiliar, when NMFS switched from the telephone effort survey to the mail FES survey, effort estimates exploded overnight, increasing eight times in some cases. Several years ago, side-by-side tests of the FES with different question ordering showed that avidity question ordering impacted the effort totals by as much as a five-fold difference between the order of the two questions. NMFS launched an investigation and is supposedly re-weighting all effort estimates. If effort estimates do indeed come down five-fold, then most of the discard problems we are seeing across many reef fish stocks go away.

For all of these reasons, the Science and Statistical Committees in the Gulf and the South Atlantic have cautioned against the use of the discard estimates for management purposes. NMFS tried to use discards to set the annual catch limit for red snapper in Amendment 59 (A59 is the red snapper secretarial amendment) which prompted this response from the State of Florida to the South Atlantic Fishery Management Council (SAFMC) in the form of a Minority Letter on A59:

“Furthermore, the Secretarial Amendment is largely driven by unvalidated discard data. Specifically, no age or length information is available to characterize these dead discards as is required for valid and accurate stock assessments. Instead, the majority of commercial discard information and all of recreational discard information is self-reported. The SAFMC’s own SSC and previous NOAA science center directors have noted that discard data are largely unvalidated, may not be accurate for the snapper grouper complex, and should not be used for management purposes…

Past Science Center Directors from NOAA Fisheries and the Council’s own Science and Statistical Committee have said discards should not be used for management because of their uncertainty. Yet, the current NOAA Regional Administrator has consistently advocated for their (unvalidated discards) use to close fishing, specifically off Florida.”

Stock Assessment Use of Discards

Carrying forward the theme that recreational and most commercial discards are self-reported, NMFS stock assessments generally treat commercial discards as reality and allow recreational discards to be a “free” term in the stock assessment models. Without getting too down in the weeds about stock assessment mathematics, complex models require some parameters to be “free” to allow for estimation. Typically, the least certain data is used as the free parameter. Total harvest in the stock models contains commercial harvest, recreational harvest, commercial discards and recreational discards.

Under the NMFS’ model specification, recreational discards become the mortality balancer. That is, recreational harvest, commercial harvest and commercial discards are treated as known and the recreational discards are estimated in the model. That means any discards not captured in the commercial self-reported discards or any cryptic mortality¹ is lumped into recreational discards.

This is all a bit “inside baseball” and doesn’t appear to have any direct impact as those model estimated discards are not reported or used for management, but I do believe they create a bias in the SSC and agency biologists, particularly in fisheries with poorly reported commercial discards or high illegal harvests. This makes it seem to those in the know that recreational discards are driving mortality estimates. By this construction, cryptic mortality may actually be driving the mortality question. One instance that comes to mind is the illegal lancha fishing for red snapper in the Gulf. That cryptic mortality is currently being attributed to recreational anglers by the stock model.

While these inner model estimates aren’t used for management per se, I do think this treatment is problematic. I’ve reviewed multiple stock assessments and the model estimates are never reported. Instead, MRIP discard estimates are reported. Even if these estimates aren’t directly impacting management, lack of transparency on how NMFS estimates discards and this sort of imprecision in the stock assessment data causes consternation. The main actionable gripe, and we have seen this many times in the management process, is that NMFS treats commercial discards as gospel when in actuality they are based on very small sample size observer coverage or are completely self-reported. This issue confounds estimating or realizing the impact of reduced recreational mortality from descending devices and venting when there is high but under reported commercial discards or other sources of cryptic mortality. It directly impacts the percentage of fish that are being helped by these technologies. Overall, however, I don’t think this issue has much impact and the largest impact is the huge overestimation of discards from the MRIP survey.

State Survey Comparisons

Fortunately, thanks to newly implemented state management regimes, we can test the validity of MRIP discard estimates using state surveys around the Gulf and South Atlantic. Florida (both coasts), Mississippi, Alabama, Louisiana and Texas all conduct their own surveys at least for reef fish and, in the case of Louisiana and Texas, for all species. Gentner Consulting Group contacted all of these states and asked for discard estimates for red snapper, gag, mutton snapper, yellowtail snapper, gray triggerfish and greater amberjack. At the time of this writing, Louisiana had provided estimates for red snapper, gray triggerfish and greater amberjack. Florida provided estimates for all species.

Table 1 contains the comparison for Louisiana. MRIP estimates are from SEDAR 98² as the current MRIP queries drop Louisiana after they took over recreational data collection in 2013. The calibrated estimates are available from NMFS³. That query, however, does not display live discards (B2 catches) and instead returns only missing cells which is an issue. MRIP should be providing these estimates in a transparent fashion. These estimates include private and for-hire modes in all waters off Louisiana. The LA Creel estimates are the state’s official estimates before any calibration to MRIP. From the table, MRIP discard estimates are 6.1 to 6.8 times HIGHER than the state level estimates. This multiplier coincidentally tracks with the increase coming from the switch to FES and may simply be due to the flaws in the FES. Hopefully, NMFS will complete their correction of the errors in that survey soon. Because MRIP does not publish state level discard estimates for Louisiana now, it is impossible to make this comparison for the other species listed above.

Table 1. LA Creel Compared to MRIP 2018-2023.

Table 2 contains the comparison between MRIP and Florida’s State Reef Fish Survey (SRFS) as taken from a SEDAR report summarizing the ratios used to “calibrate” the SRFS up to match MRIP numbers. Florida was not able to complete the data request for discard estimates for the species above for both the Gulf and South Atlantic but did direct this exploration to the SEDAR reports detailing the calibration ratios for gag, gray triggerfish, greater amberjack, red grouper, red snapper, and vermillion snapper. Overall, SRFS discard estimates are two to three times less than MRIP consistently, also tracking the assumed effort overages in the current FES. The estimates in Table 2 are equivalent to the “difference multiplier” in Table 1 for Louisiana. It is likely that when Florida completes our data request for both the South Atlantic and the Gulf that these ratios will change.

Table 2. Discards Calibration Ratio for Selected Species in the Gulf of America (through year 2019).⁴

For the South Atlantic, SEDAR 90 contains the calibration ratio for South Atlantic red snapper, which they estimated at 2.07 through 2024.⁵ The only other South Atlantic species that has been examined by SEDAR was yellowtail snapper and SEDAR 96 found that ratio to be 1.83 through 2023.⁶ Across all the species examined, the Florida state survey was two to three times lower than the MRIP for discards.

Summary

Until some validation is conducted, extreme caution needs to be used with the DPUE estimates from MRIP. The SSC’s know that and ostensibly NMFS scientists know that. Instead, NMFS management is using suspect discard numbers to drive management that calls for draconian restrictions on recreational angler access.

Additionally, the FES is currently undergoing a complete redesign to test and eliminate the overages found as discussed above. The difference multipliers/calibration ratios were derived to force the better state survey to equal MRIP which we have always maintained is a huge mistake scientifically. This quick analysis shows that that difference is driving a fictional “discards crisis.” The end result is that NMFS is knowingly using flawed estimates to drive policies that reduce recreational fishing access.

The entire recreational accountability fiction is being driven by discredited discard estimates which are driven by survey biases and by the inflated effort estimates from the shift to the FES survey. All of these factors are known and yet are being intentionally ignored by NMFS. The question is why, and that is a much more difficult thing to explain.

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¹Cryptic mortality is any unobserved mortality. It could include red tide events, weather events, illegal fishing or any other mortality that is not measured and included in the stock assessment
²Nuttall, Matthew A. 2024. General Recreational Survey Data for Red Snapper in the Gulf of
Mexico. SEDAR98-DW-05. SEDAR, North Charleston, SC. 119 pp.
³https://www.st.nmfs.noaa.gov/SASStoredProcess/guest?_program=%2F%2FFoundation%2FSTP%2Fmrip_qry_index&qrycatch=Select+a+Catch+Query&qryeffort=Select+an+Effort+Query&qryparticipation=Select+a+Participation+Query&subnational=Goto+Query
⁴Cross, Tiffanie A., Colin P. Shea, and Beverly Sauls. 2020. A ratio-based method for calibrating GRFS and MRIP-FCAL estimates of total landings (numbers and pounds of fish), and releases (numbers of fish). SEDAR72-WP-04. SEDAR, North Charleston, SC. 10 pp.
⁵Ramsay, Chloe. 2025. A ratio-based method for calibrating estimates of total landings (numbers and pounds of fish), releases (numbers of fish), and total trips from MRIP-FCAL to SRFS for Red Snapper (Lutjanus campechanus) in the South Atlantic. SEDAR90-DW-19. SEDAR, North Charleston, SC. 18 pp.
⁶Ramsay, Chloe, Tiffanie A. Cross, Colin P. Shea, and Beverly Sauls. 2024. A ratio-based method for calibrating MRIP-SRFS recreational fisheries estimates for southeastern US Yellowtail Snapper (Ocyurus chrysurus). SEDAR96-WP-05. SEDAR, North Charleston, SC. 14pp.