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4 Technical Considerations in Developing Rebuilding Plans
Pages 61-84

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From page 61...
... . of factors: The fishing mortality corresponding to this MSY, FMSY, is the rate of population removal by the fishery that will maintain • MSY depends on fishing practices.
From page 62...
... the target fishing mortality for productive stocks to • MSY depends on environmental conditions. MSY is avoid overfishing unproductive stocks is common derived from a production function, which depends and is referred to as "weak stock management." For on biological processes, including reproduction, example, catches of yellowtail rockfish off the U.S.
From page 63...
... There is ber of recruits and measures of reproductive potential may a tradeoff between choosing an uncertain reference point or be so uncertain that proxies (such as F35% or F40%, defined as a potentially biased proxy. More years of data over a greater the fishing mortality that reduces the average spawning stock range of stock abundance should allow for estimation of biomass-per-recruit to 35% or 40% of the unfished level)
From page 64...
... New England Fishery Management Council Species Group Overfished Definition Overfishing Definition Northeast Multispecies GOM Cod B<½ BMSY F>F40% GBK Cod B<½ BMSY F>FMSY GOM and GBK Haddock B<½ BMSY F>FMSY American Plaice B<½ BMSY F>FMSY Witch Flounder B<½ BMSY F>F40% GOM and GBK Winter Flounder B<½ BMSY F>FMSY CC/GOM and GBK Yellowtail Flounder B<½ BMSY F>FMSY SNE/MA Yellowtail Flounder B<½ B35% F>F40% Other Speciesa B<½ BMSY F>FMSY Scallops B<½ BMSY F>MFMTb Monkfish B<½ BMSY F>MFMTc Small Mesh Multispecies Silver Hake B<½ BMSYproxy F>F0.1 Northern Red Hake 3 yr mean CPUEsurvey<1.6 kg/tow F>FMSY proxy Southern Red Hake CPUEsurvey d<25th percentile of CPUEsurvey series NA Offshore Hake CPUEsurvey d<25th percentile of CPUEsurvey series NA Dogfish B<½ BMSYproxye F>MFMTf Red Crab B<½ BMSY F>FMSY g or Average CPUE20% Barndoor CPUEsurvey d<½ 0.81 kg/tow 3 yr CPUEaverageh>30% Thorny CPUEsurvey d<75th percentile of CPUEsurvey series 3 yr CPUEaverageh>20% Smooth and Clearnose CPUEsurvey d<75th percentile of CPUEsurvey series 3 yr CPUEaverageh>30% Rosette CPUEsurvey d<75th percentile of CPUEsurvey series 3 yr CPUEaverage h>60% a Pollock, redfish, white hake, Atlantic halibut, ocean pout, windowpane flounder, SNE/MA winter flounder, wolfish, herring. b MFMT is based on a stochastic YPR model.
From page 65...
... South Atlantic Fishery Management Council Species Group Overfished Definition Overfishing Definition Shrimp B<½ BMSY F>FMSY Spiny Lobstera NA NA Black Sea Bass B<(1–M) BMSY F>FMSY Red Porgy B<(1–M)
From page 66...
... (g) North Pacific Fishery Management Council Species Group Overfished Definition Overfishing Definition Groundfish Tiers 1 & 2 B<½ BMSY Catch>OFL Tier 3 B<½ B35% Catch>OFL Tiers 4-6 N/A Catch>OFL Bering and Aleutian Islands Crab Tiers 1 & 2 B<½ BMSY Catch>OFL Tier 3 B<½ B35% Catch>OFL Tier 4 B<½ BMSYproxya Catch>OFL Tier 5 NA Scallops NA Catch >OFL a An average biomass selected by the NPFMC SSC as reflecting when the stock was at BMSY.
From page 67...
... can lead to a marked change in allowable fishing mortality and hence catch. Paradoxically, Harvest Control Rules rebuilding HCRs can result in an increase in removals com FREBUILD is defined as the fishing mortality rate that would pared to what would have been expected under the "normal" allow the stock to recover with 50% or greater probability HCR, as can be seen by extending the dashed diagonal line (the probability is a management choice)
From page 68...
... an HCR for stocks that have been declared overfished, illustrating an abrupt discontinuity in allowable fishing mortality, and (c) an HCR that does not have any discontinuities.
From page 69...
... , the age structure of the Most stock assessments and associated projections do population, mean generation time, productivity, and fishing not include all of the relevant sources of uncertainty (Punt et selectivity parameters, all of which are imprecise. A model al., 2012a)
From page 70...
... not a stock is under a rebuilding plan, involves the use of a Furthermore, model averaging may preclude deeper undersingle best estimate of current or projected stock size. Often standing of the consequences of alternative characterizations a range of stock assessment models of varying levels of of states and natures and identification of the associated complexity or several alternative configurations of a stan- risks that is often the result of debate and consensus builddard stock assessment model are applied, and the best of ing, especially if the models under consideration are highly these is selected using some formal model selection criteria, contradictory (Schnute and Hilborn, 1993)
From page 71...
... The review can range scientific and management uncertainty aims to reduce the from comparing catches expected under the rebuilding plan risk of overfishing occurring, it is unknown whether, and with those actually taking place, to reviewing and updating by how much, long-term potential yield is sacrificed. MSE stock assessments, which might result in updated estimates should be used to quantify the likely tradeoff between risk of BMSY (or its proxy)
From page 72...
... . The litigation, indicating that assessments are more contentious process that defines the frequency and use of New England in some regions (thus the review processes are more ­onerous stock assessments is currently under review.
From page 73...
... This loss Results from updated stock assessments are compared in yield is expected because FMSY is a limit reference point, with projections to evaluate progress toward rebuilding but it is exacerbated when unproductive stocks are placed targets and thus to guide adaptive management decisions. under rebuilding plans.
From page 74...
... , annually increase net benefits from fisheries. updated stock assessments are the norm, which are typically based on long-term catch histories and survey data, result ing in relatively accurate biological production estimates Data-Poor and Knowledge-Limited Stocks and allowing for the evaluation of projections under various The 2006 amendments to the MSFCMA are most ­readily management scenarios.
From page 75...
... (2010) defined data-poor methods as those that could be used to develop qualitative or quantitative control rules, without the guidance of a full stock assessment.
From page 76...
... , result in a reduction input control rules (e.g., effort controls) , iteratively and in fishing mortality and stock growth and greater likelihood adaptively, as stocks increase or decrease.
From page 77...
... All four stock declared overfished by the National Marine Fisheries Service assessments exhibited an inverse relationship between F (NMFS) in January 2000 after stock assessments for the pop- and B, even after the stock dropped below BMSY.
From page 78...
... The management cedures for CRA7 and CRA8 involve determining the TAC procedures are constructed with the intent to rebuild stocks for a year based on the catch rate for the previous year when that are below target levels, but there is no pre-specified rate the function relating the catch rate to the TAC is piecewise of recovery or time to recovery. The management procedures linear (New Zealand Ministry of Fisheries, 2011a)
From page 79...
... According to the assessment conducted in 2011, the outlook for the SBT stock is positive, given that fishing mortality has been reduced to below FMSY (CCSBT, 2011) and a management procedure designed to TAC (i.e., a recommended change in TAC of 1% will be adjust TACs in response to future indicators of stock status ignored)
From page 80...
... . Parameters of a selected subset of candidate management procedures were adjusted to meet Speckled Hind and Warsaw Grouper in the the interim rebuilding target at a range of time frames and South Atlantic Region with different probabilities, as specified by the CCSBT.
From page 81...
... . Amendment 10 established Essential cies range within, but extend beyond the jurisdiction of, the Fishery Habitat and Habitats of Particular Concern (EFH and South Atlantic Fishery Management Council (SAFMC)
From page 82...
... In 2005, the CFMC designated the complex as be better suited for managing data-poor reef fish­ overfished and undergoing overfishing, commencing a eries than control rules based on FMSY. 10-year rebuilding plan (CFMC, 2005)
From page 83...
... Figure 4-10 fixed image are problematic because of underreporting, and approximate region in an effort to reduce fishing mortality. These closures adjustment factors are estimated based on all available data include closure for red hind near St.
From page 84...
... Alternative harvest control on input controls to reduce fishing mortality may be more rules that gradually reduce fishing mortality as estimated effective and defensible than strategies based on annual stock size falls below BMSY could result in a lower likeli- catch limits and BMSY targets. hood of a stock becoming overfished, as well as provide for rebuilding if necessary.


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