caribbean fishery management council meeting 28-29 june 2011 1
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Caribbean Fishery Management Council SSC Meeting
SSC Report to CFMCMeeting held 24-25 June 2011Caribbean Fishery Management Council Meeting 28-29 June 20111SSC addressed the following:CFMC interest in (expressed by RA Crabtree) setting OFL levels above average landings for healthy stocksUsed the ORCS Working Group Approach (Berkson et al. 2011) to determine OFL and make recommendations to CFMC regarding ABC Determined if an FMU was lightly, moderately or heavily exploited associated with a scalar to apply to the landing statisticDetermined the time series of landings on which to base OFLDetermined the landings statistic(s) to be used as the basis for determining OFLApplied the scalar to the landing statisticABC calculationSSC classified FMUs as to whether they were at low, moderate, or high risk of being overfishedCouncil is responsible for the scalar to apply to OFL to get ABC2CFMC asked SSC to consider the following: CFMC asked the SSC to consider setting OFL levels above average landings for healthy stocksRA Crabtree provided rationale: If the you believe a stock is healthy with no signs of overfishing, but you then set the OFL at average catch, aren't you then saying that overfishing has been occurring on average about half the time? Isn't that inconsistent with the starting premise that the stock is healthy? So if a stock healthy, shouldn't the OFL be a level above average catch?
3SSC ResponseSetting OFL equal to average catch over a period of time does not mean that overfishing occurred about half the time. Catch can fluctuate and can be higher if fishing is maintained at Fmsy (fishing morality rate at MSY (Maximum Sustainable Yield).However, managing by a constant fishing morality strategy requires info on stock size and fishing mortality so that catch can be adjusted annually.When average catch is used to estimate fishing mortality this information is lacking constant catch strategy required.4CFMC request continuedRA Crabtree also pointed out that the Gulf of Mexico Councils SSC has been working on the following:Based on expert evaluation of the best scientific information available, recent historical landings are without trend, landings are small relative to stock biomass, or the stock is unlikely to undergo overfishing if future landings are equal to or moderately higher than the mean of recent landings...... Set the overfishing limit equal to the mean of recent landings plus two standard deviations.
5SSC ResponseThe conditions for applying this approach (i.e., landings without trend, landings small relative to stock size, stock unlikely to undergo overfishing) are not generally applicable to Caribbean stocks because of insufficient information. Furthermore, the CFMC SSC is not aware of a scientific basis for assuming that OFL occurs at a "catch equal the average plus two standard deviations. This corresponds to assuming that a catch that occurred rarely (about 2.5% of the time) during the averaging period could have been taken as a constant catch without overfishing. Why should this be true in general?
66OFL Determination using the ORCS (Only Reliable Catch Stocks) Working Group Approach
7Step One Determine if an FMU (Fisheries Management Unit) was lightly, moderately or heavily exploited using evidence-based scoring system of selected attributes.Commercial and recreational landings were scored separatelyCommercial: Six of the nine original attributes were scored for each FMU based on criteria provided in the ORCS reportRecreational: 3 4 of the attributes were scored for each FMUAttributes were scored as follows:1 low level of exploitation2 medium level of exploitation 3 high level of exploitation
8Attributes Table Example Results for Puerto RicoAttributesPorgiesGoatfishJacksAngelfishExploitation1Not IncludedRefugia23333Behavior32222Morphology42122Bycatch52321M = Natural mortality62222Rarity1Not IncludedValue71211Trend1Not IncludedAverage2.002.172.001.83Ecological value29Explanation of attributes REFUGIA - Presence of extensive natural or managed refugia. This applies to species that were not highly mobile as adults in relation to the size of the refugia. Value of 1 - less than 50% of habitat is accessible to fishing, 2 - 50-75%, 3 - >75%.
SCHOOLING, aggregation, or other behavior responses affecting capture by fishing gear. Species specific behavior characteristics can make a species more or less susceptible to capture by a fishing gear.
School of yellowtail snapper schools of yellowtail are harvested with seine nets on St. Thomas/St. John.10Explanation of attributes (cont.)Morphological characteristics affecting capture, i.e. large spines, body shape.
Targeting of stock - Is the stock targeted by the fishery or is it bycatch. Stocks that are primarily bycatch are likely to be lightly exploited relative to the targeted stocks. However non-targeted stocks may still become overfished if it is less productive than the targeted stock.
Four-eye butterfly fish susceptible tocapture by traps and nets because of itsbody shape. It is bycatch.11Explanation of attributes (cont.)Natural mortality - For stocks subject to similar fishing mortality rates, those with low natural mortality have a higher likelihood of becoming overfished than those with a higher natural mortality.
Blue fry high natural mortalityGraysby moderate to high natural mortality12Explanation of attributes (cont.)Highly valued fish stocks are more susceptible to overfishing or becoming overfished.
Surgeonfish are considered trash fish in Puerto Rico sell for $0.75/lb.
Red grouper (below) and mutton snapper (above) are highly valued stocks in the U.S. Caribbean.
13Recommended scalar to apply to OFLsStock CategoryLightly exploited B > B 65%Moderately exploitedB approximately BmsyHeavily exploitedB < B 20%2.0 X catch statistic1.0 x catch statistic0.5 x catch statisticCorresponding Average Attribute Values< 1.51.5 2.5> 2.51414ResultsAverage attribute scores ranged from 1.67 for tilefish to 2.5 for spiny lobster Therefore, all FMUs, including both commercial and recreational landings, were determined to be moderately exploited and the scalar applied was 1.0 x the catch statistic
15Step two Selection of Time Series for Puerto RicoLandings time series from 1988 2009 was selected.Expansion factors for landings prior to 1988 were unknownPrior to 1988 landings may have included catches from outside the Puerto Rican EEZAfter 1988, the DNER lab has institutional knowledge of the expansion factors and the rationale supporting their application to annual landings
Landings data for Puerto Rico16Step two Selection of Time Series for Puerto Rico (cont.)Landings from 1988 onwards show a high degree of variability potentially owing to a variety of factorsNatural variability in fish populationsAccuracy of data% of fishers reportingAccuracy of self-reported landings in the past because of difficulty in accurately identifying species and more recently because fishers are asked to report and submit trip tickets without port samplers assistanceMisreporting because of discontent with new regulations
Landings data for Puerto Rico17Step two Selection of Time Series for Puerto Rico (cont.)Expansion calculations changed in 2003 from participation based calculation to fish weight based calculation.Declines in reported data likely because of many fishers not submitting trip reports because of discontent with new regulatory regime.In conclusion, no substantial time period is free of changes and impacts.
Landings data for Puerto Rico18Commercial Landings Step 3: Selecting an appropriate landings statisticThe SSC selected the median* of the commercial landings values for the time series 1988 2009 for each FMU with adequate landings data as the basis of OFL.Rationale:More robust to errors of measurementLess sensitive to outliersThree FMUs (Angelfish, Surgeonfish and Tilefish FMUs) were treated differently.They are not commercially targeted in Puerto Rico because they are considered either trash fish (surgeonfish, tilefish) or 2nd class fish (angelfish) and sold for $0.75 - $1.00/lbThese three FMUs had very low reported commercial landings that didnt reflect what was considered sustainable for the fishery.These were considered pre-emptive quotas quotas for underdeveloped fisheries that the CFMC would probably not want to get out of hand. The SSC selected two times the highest annual recreational landings recorded as the basis for commercial OFL for the Angelfish, Surgeonfish and Tilefish FMUs.
* Median = middle value in a range of values, with half the values above the median and half below the median19Recreational Landings Step 3: Selecting an appropriate landings statisticLandings were based on MRFS data which was available from 2000 2009OFL based onMedian for FMUs with annual landings in most if not all yearsFor FMUs with a median value of 0 (Angelfish, Tilefish, Surgeonfish) the maximum landings were the basis for OFLMRFSS does not gather data on spiny lobster. The SSC based the OFL for spiny lobster was the 2005 SFA Amendment that allocated 32% of total spiny lobster landings to the recreational sector
20Table 1: OFL values based on selected statistic measures x 1.012 x max rec landings, 2median, 3 maximum, 4rec landings = 32% of total landingsFMU GroupCommercial Landings(lbs)Recreational Landings(lbs)Total Landings(lbs)Angelfishes11,97815,989317,967Aquarium Trade4,95325,920210,873Boxfish95,68325,1292100,812Goatfishes19,5172402219,919Grunts202,66225,5872208,249Jacks95,621256,6682152,289Lobster364,3552171,4614535,816Others39,8612Porgy27,48822,863230,351Squirrelfish18,51424,323222,837Surgeonfishes9,57214,786314,348Tilefish10,84615,423316,269Trigger and filefish64,972224,365289,337Wrasses60,16325,611265,7742121Calculation of ABC from OFL