Failure to eliminate overfishing and attain optimum yield in the New England groundfish fishery (original) (raw)
Related papers
PloS one, 2013
There is considerable variability in the status of fish populations around the world and a poor understanding of how specific management characteristics affect populations. Overfishing is a major problem in many fisheries, but in some regions the recent tendency has been to exploit stocks at levels below their maximum sustainable yield. In Western North American groundfish fisheries, the status of individual stocks and management systems among regions are highly variable. In this paper, we show the current status of groundfish stocks from Alaska, British Columbia, and the U.S. West Coast, and quantify the influence on stock status of six management tactics often hypothesized to affect groundfish. These tactics are: the use of harvest control rules with estimated biological reference points; seasonal closures; marine reserves; bycatch constraints; individual quotas (i.e., 'catch shares'); and gear type. Despite the high commercial value of many groundfish and consequent incentives for maintaining stocks at their most productive levels, most stocks were managed extremely conservatively, with current exploitation rates at only 40% of management targets and biomass 33% above target biomass on average. Catches rarely exceeded TACs but on occasion were far below TACs (mean catch:TAC ratio of 57%); approximately $150 million of potential landed value was foregone annually by underutilizing TACs. The use of individual quotas, marine reserves, and harvest control rules with estimated limit reference points had little overall effect on stock status. More valuable fisheries were maintained closer to management targets and were less variable over time than stocks with lower catches or ex-vessel prices. Together these results suggest there is no single effective management measure for meeting conservation objectives; if scientifically established quotas are set and enforced, a variety of means can be used to ensure that exploitation rates and biomass levels are near to or more conservative than management targets.
Goals and strategies for rebuilding New England groundfish stocks
Fisheries Research, 2008
Rebuilding depleted fishery resources is a worldwide problem. In the U.S., the Magnuson Stevens Fishery Conservation and Management Reauthorization Act (MSRA) of 2007 requires that "Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield from each fishery.. .". However, translating this legal mandate into tangible goals and actions presents several technical challenges, especially for resources that have been chronically over-exploited. For example, maximum sustainable yields and biomass reference points are poorly estimated for stocks that have been overfished for a long period of time and are poorly defined unless sufficient data are available from periods of low-fishing mortality rates and relatively high-stock sizes. The conundrum of how to set meaningful rebuilding goals given limited information on the population dynamics and trophic interactions of a rebuilt stock can generally be addressed through adaptive management procedures incorporating learning about density-dependent population dynamics. Monitoring changes in life history parameters and recruitment is critical for successful rebuilding strategies realizing the full yield potential of rebuilt stocks while periodic re-evaluation of rebuilding targets is also needed to address uncertainties due to density dependence, trophic interactions or environmental factors. This paper summarizes the development and implementation of goals and strategies to rebuild New England groundfish stocks over the past decade. Management is particularly challenging because the true yield and population size potentials of these interacting stocks is unknown due to chronic overfishing throughout the modern history of the fishery, uncertainty in compensatory/depensatory population dynamics and in the degree of stationarity in environmental control of groundfish recruitment.
This report provides an evaluation of the economic and social performance of active limited access Northeast groundfish vessels for the 2010 fishing year (May 2010 through April 2011) and provides additional analyses to those contained in the Report for Fishing Year 2010 on the Performance of the Northeast Multispecies (Groundfish) Fishery (May 2010 – April 2011) (Kitts et al. 2011). The additional analyses in this report are: 1. inclusion of vessel and sector costs in an evaluation of nominal net revenue change (Section 4.2); 2. incorporation of new vessel ownership information (Sections 6.3-6.8); 3. more revenue distribution metrics (Section 6.6); 4. a measure of vessel productivity (Section 4.3); 5. an evaluation of Annual Catch Entitlement trading (Chapter 5); and 6. a qualitative discussion of potential changes in the number of crew and other jobs (Section 7.4). These new analyses, and those from the previous report, revealed some notable changes in the fishery between 2007 and...
The Magnuson-Stevens Fishery Conservation and Management Reauthorization Act of 2006 requires Regional Fishery Management Councils to set annual catch limits for all stocks or stock complexes in Federal fishery management plans beginning in 2011. Most species listed in the Pacific Coast Groundfish Fishery Management Plan have not been assessed, in large part due to data limitations. Estimates of sustainable yield for many these species were previously based on undocumented, ad-hoc analyses. We present estimates of sustainable yield for 50 of these stocks using two recently developed models designed to inform management of data-poor stocks. These models rely on recently reconstructed time series of historical catch for west-coast groundfish species and species-specific information related to stock productivity. For this set of data-poor stocks, recent landings statistics reflect shifts in the relative importance of certain species to west-coast fisheries (e.g. increased catches of nearshore and slope rockfish species relative to shelf species), largely due to recent regulatory actions. We provide estimates of overfishing limits (OFLs) for each of the 50 stocks along with comparisons to recent catch levels. Our results suggest that status quo harvest levels range from light exploitation of some stocks to potential overfishing of others. This information could help inform decisions regarding prioritization of future stock assessments for unassessed species. OFLs are expressed as probability distributions, reflecting our uncertainty in model parameters. We select median values as point estimates of OFL, as this statistic is most consistent with National Standard 1 guidelines.
In Search of Optimal Harvest Rates for West Coast Groundfish
North American Journal of Fisheries Management, 2002
In this paper, I explore how patterns of compensatory mortality, as assessed through stock-recruitment relationships, may influence optimal harvest rates and relative yields for several West Coast groundfish stocks. To do this, I revisited Clark's (1991) groundfish life history model and maximin (i.e., maximize the minimum) yield approach to evaluate target harvest rates for five stocks (Dover sole Microstomus pacificus, lingcod Ophiodon elongatus, sablefish Anoplopoma fimbria, Pacific hake Merluccius productus, and widow rockfish Sebastes entomelas) using recent estimates of fishery and life history parameters and stock-recruitment data. I found that a spawningstock-per-recruit target of roughly 35% of its unfished amount would be reasonable for these stocks if Clark's assumed stock-recruitment parameters are representative and the policy goal is a maximin yield. In contrast, use of estimated stock-recruitment parameters suggested more conservative percentages of the unfished spawning stock per recruit and more conservative harvest rate targets for most stocks. A key implication of this work is that Clark's groundfish life history model is sensitive to the stock-recruitment shape parameters. As a result, these parameters should be estimated where possible or imputed using results from meta-analyses. Overall, a conservation target of roughly 35% of the unfished spawning stock per recruit is very likely too low for lingcod, sablefish, and widow rockfish stocks under current environmental conditions, but it may be adequate for Dover sole and Pacific hake stocks.
Use of Known-Biomass Production Models to Determine Productivity of West Coast Groundfish Stocks
North American Journal of Fisheries Management, 2002
Known-biomass production models use a biomass time series produced by a stock assessment and thereby avoid the imprecision associated with estimating a catchability coefficient. Fluctuations or trends in known biomass are fully as informative as catch (which is used in conventional production models) in estimating stock productivity. Known-biomass production models provide a useful supplement to stock-recruitment models and can serve as a cross-check on the sensibility of stock-recruitment model results. Application of known-biomass production models (ASPIC) to eight stocks of West Coast groundfish shows that current abundances (B) are moderately to seriously below those associated with the maximum sustainable yield (MSY; B is less than B MSY in six of eight cases and less than one-half of B MSY in four of those cases). Recent exploitation rates are lower than those in earlier years and in most cases are now near their appropriate levels, including the rates for stocks that are rebuilding. Harvest policies during the 1990s, which specified fishing mortality rates corresponding to spawning potential ratios of 35% and 40% (i.e., F 35% and F 40% ), were too aggressive for most stocks of West Coast
2015
This series is a secondary scientific series designed to assure the long-term documentation and to enable the timely transmission of research results by Center and/or non-Center researchers, where such results bear upon the research mission of the Center (see the outside back cover for the mission statement). These documents receive internal scientific review, and most receive copy editing. The National Marine Fisheries Service does not endorse any proprietary material, process, or product mentioned in these documents. All documents issued in this series since April 2001, and several documents issued prior to that date, have been copublished in both paper and electronic versions. To access the electronic version of a document in this series, go to http://www.nefsc.noaa.gov/nefsc/publications/.
Using yield per recruit analysis to determine fish stock status
2018
During the past decade, the fishing industry in Southeast Asia had been confronted with concerns on declining fishery resources due to overfishing, and more particularly because of the continued practice of illegal, unreported, and unregulated (IUU fishing) as well as degradation of the habitats that bring about negative impacts to the economic, social and ecological attributes of fisheries affecting food security. It has therefore become necessary that management measures should be established for the sustainable management of the fishery resources in general. However, attempts to establish such fisheries management measures have encountered problems on inadequacy of data for stock assessment that hinder the efforts to develop such measures. During discussions on the sustainable utilization and management of fishery resources in the Southeast Asian region, the need to improve data collection had always been raised on various occasions for the development of appropriate management m...