Catch Shares Improves Both Science and Catches

EDF Senior Scientist, Doug Rader

EDF Chief Oceans Scientist, Doug Rader

The track record for catch shares in fishery management is abundantly clear: better science for managers and better access for fishermen.  Certainly, “science vs. catch shares” is a false choice – catch shares provides the best chance to achieve high-powered science while getting fishermen back on the water and back to work. 
Here’s why.

Science in Fisheries Management

Irrespective of the type of management being used, federal law and regulations require that fishing levels be set to both prevent overfishing and rebuild overfished stocks, based on the best available scientific information.  The total fishing mortality for all fishing sectors (commercial, charter boats and private anglers), including both landed and discarded dead fish, cannot by law exceed “overfishing limits” identified by fisheries scientists.

Two kinds of information are used to assess fish stock conditions and set the overfishing limits, fishery-independent data (collected directly by scientists to judge stock conditions), and fishery-dependent data (sampling of fish caught by fishermen, and affected by the fishing mechanism and regulations, typically using catch monitoring or catch accounting methods).  Each type provides different, valuable information about what’s out there, and what is caught.

When there are lots of data of both types, and they are collected using robust methods, the uncertainty in the biology is greatly reduced and we have a much better understanding of what’s happening.  When data are poor in one or both categories, there is a higher level of biological uncertainty, and less confidence that managers understand what’s really occurring in the fishery.

Under federal regulations, biological uncertainty must be subtracted from the overfishing limits to create lower “allowable biological catches” that cannot be exceeded by managers. 

In addition, there is often considerable uncertainty in estimating how a proposed management system will work to achieve allowable biological catches.  Management uncertainty (how well management measures like bag limits, size limits, closures, or catch shares perform in actually hitting management targets) must be subtracted from allowable biological catches in setting “annual catch limits” for fisheries or fishing sectors.

Thus, all types of uncertainty must be accounted for.  The greater the total uncertainty, the lower the allowable catch levels can be—and the less fish for fishermen to catch, for any given stock condition. 

Finally, the levels of fishing allowed for overfished stocks are also set based on how fast those stocks are able and required to rebuild.  In nearly every case, the regional fishery management councils have allowed the longest legal rebuilding time, with the lowest allowable probability of actually rebuilding, given the biological uncertainty involved (50% probability, established in the courts and now by regulation), and the highest legal landings, even though that slows down rebuilding.

Catch Shares Improves Both Science and Catches

Initially, new catch shares fisheries operate with the same science-based catch limits that non-catch shares fisheries use, as explained above.  However, because well-designed catch share programs also feature improved monitoring systems (including catch accounting) and improved and collaborative science, catch shares quickly outperform traditional approaches, both scientifically and in terms of access to fish for fishermen, for four specific reasons. 

  1. Under catch shares, the quality and quantity of fishery-dependent data skyrockets, both improving estimates of overfishing levels and significantly reducing scientific uncertainty, thus raising allowable biological catches for any given actual stock condition.
  2. Collaborative science means improved fishery-independent data, which means not only more accurate overfishing levels, but also reduced scientific uncertainty, and allowing further increases in allowable biological catches.
  3. Under catch shares, compliance with allowable catch targets also skyrockets – with fishermen on average catching 5% below what they could have caught – reducing management uncertainty, and raising allowable catch levels.
  4. High compliance rates with biologically-based targets means faster and more certain rebuilding (versus the underperformance of other approaches, where access to growing stocks is delayed), hastening the day when greater yields are allowed.

These are not just theoretical findings.

The Redstone (2007) review of catch share fisheries showed not only extraordinary compliance, but also that catch shares improved science (i.e. reduced uncertainty) dramatically.  Collaborative science improved the available data sets, and increased monitoring ensured more accurate estimates of total fishing mortality (i.e. both bycatch and landings).  Overall, uncertainty in biomass estimates was reduced from an average of ±50% to an average of ±25% within five years after catch shares were implemented. Especially dramatic improvements occurred in British Columbia halibut and sablefish, where uncertainty shifted from ±100% and ±75%, respectively, to ±50% and ±20%.

The often-quoted Essington (PNAS, 2009) analysis of catch shares fisheries reinforced these conclusions, showing markedly greater consistency under catch shares, and stating:

“More consistent and predictable fisheries may provide tangible benefits for improving the scientific advice in support of fisheries policies. Evaluation of management strategies [endnote omitted], for instance, can be made more precise if fisheries respond to management in predictable ways. One important way that the fisheries in the present study responded to catch shares was to sharply reduce interannual variability in the catch:quota ratio; catch share fisheries generally captured all of the annual catch quotas and avoided quota overages. Viable explanations for this response include the end to the race-to-fish, improved catch reporting systems, and changes in the incentive structure whereby individual fishing participants are penalized for exceeding their own individual quotas and may trade quotas within a fishing season [endnotes omitted]. The result is vastly reduced “implementation error,” one of the three sources of uncertainty that can contribute to fishery collapses [endnote omitted].

"Reduced variance in population status (e.g., exploitation rates) in catch share fisheries might also be an indication that management is more effective at maintaining stocks near their management reference points (i.e., they avoid large declines in abundance through excessive exploitation rates and adapt policies as environmental conditions change). This response may reflect the incentives that catch shares provide to participants for improving assessment and advocating for more conservative catch quotas [endnote omitted]; when management targets were specified, exploitation rates were always below the target levels following catch share implementation, and population biomass tended to move toward
target levels. The enhanced consistency in population biomass and exploitation rates is reflected in the landings data, which exhibited significantly reduced variability in the present study and in the study by Costello et al. [endnote omitted], suggesting that catch share fisheries may provide a more stable delivery of fishery products.”

Certainly having good science – collected both through improving fishery-dependent and fishery-independent means – is critical to reducing overall uncertainty and maximizing both rebuilding and allowable catches.  We must support and invest in both aspects. 

But the bottom line is that fishery managers have a readily available tool in catch shares that can make a big difference in improving science and increasing the amount of fish available for fishermen to catch.

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