1 / 11

Gulf of Maine Winter Flounder SARC 52 (Terminal year 2010)

Gulf of Maine Winter Flounder SARC 52 (Terminal year 2010). Modeling (VPA, SCALE, ASAP). Conflicting signals in the data sources exist (large decrease in catch over the time series with little change in the indices or age structure in both the catch and surveys).

truman
Download Presentation

Gulf of Maine Winter Flounder SARC 52 (Terminal year 2010)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Gulf of Maine Winter Flounder SARC 52 (Terminal year 2010) • Modeling (VPA, SCALE, ASAP).Conflicting signals in the data sources exist (large decrease in catch over the time series with little change in the indices or age structure in both the catch and surveys). • Direct survey 30+ cm area swept biomass estimates. Higher catchability and better coverage with the updated NEFSC survey.

  2. Exploitable Biomass = 30cm+ biomass index per tow /1000 x total survey Area/tow footprint x 1/q Q = 0.6 Exploitation rate = catch / 30cm+ biomass.

  3. Combined Surveys 30+ Biomass Estimate

  4. The Plan • Update catch (MRIP Ab1 + b2 2004-2013, commercial landing, lg mesh trawl discards, gillnet discards, shrimp discards). • Converted survey indices for trends (NEFSC, MDMF, MENH). • Updated 30+ area swept biomass for each component (NEFSC, MDMF, MEHH) • Estimate uncertainty with Dr. Rago’s code

  5. Length based YPR m=0.3 FMSY = F40% = 0.31 Exploitation rate = 0.23 Knife edge selectivity at 30 cm

  6. The Issue Catch is very low (in the 300 mt range over the last few years, ABCs set at 1050 mt). Stock biomass does not seem to respond to the very low catches. There are signs of declining biomass in the surveys.

  7. Possible use of GB yellowtail assessment logic? Little information on the Q assumption. There are questions with herding and footrope escapement in the surveys. The GB yellowtail benchmark borrowed from flatfish literature estimates (0.37 on the doors). Assuming 0.37 is similar to assuming 1.0 on the wings. Should or can this logic be used in this assessment or do we rely on GB winter flounder Q inferences?

  8. Question 2 Do we use the Fall 2013 estimate or can we consider using the Spring estimates? The logic to use the Fall survey makes biological sense but recent Spring estimates are higher.

More Related