- Following ICCAT’s recently concluded Atlantic bluefin stock assessment data preparation meeting, here is a brief update on the ICCAT plan for the 2017 Atlantic bluefin tuna stock assessments that are being worked on through this summer and fall with an early October publication date. ABTA’s International Bluefin Research Program (IBRP) supported 3 independent scientists to this important ICCAT meeting in Madrid and Dr. Doug Butterworth had maximum input.
Initially, ICCAT’s plan was to develop a Mixing Model that takes into account the significant presence of migrants from both east/Mediterranean and west bluefin stocks in Atlantic foraging areas, and this would be used together with east and west abundance data to develop the 2017 stock assessments. The presence of east/Med bluefin in our fishery is validated by conventional and electronic tagging and otolith sampling from the last 40 years. Even though progress has been substantial, scientists are not fully confident that a mixing model, with all of its complexities, is ready to replace the current “two-stock”, no-mixing model.
Although it was a disappointment that a mixing model was not achievable for the upcoming stock assessments, the Data Preparation meeting did conclude a thorough review of the east and west abundance indices which will drive the 2017 stock assessments using traditional stock assessment methodologies. As you will recall, the prior assessment in 2014 indicated that the key abundance indices were showing a substantial increasing trend, leading NMFS Miami Chief bluefin scientist Dr. Clay Porch to conclude that the data on bluefin was the most optimistic on record. The recent Data Prep meeting reviewed the latest abundance indices and a continued increasing trend has been confirmed and strengthened. The bottom line is that the 2017 stock assessment should be the most positive assessment on the status of biomass since ICCAT bluefin assessments began. There will be additional assessment methods used to confirm the dramatically improving status of western bluefin and this will include the “SCAL Method” developed by Drs. Butterworth and Rebecca Rademeyer under our fishermen-supported IBRP.
ICCAT scientists have also been working on a Management Strategy Evaulation (MSE) for Atlantic bluefin, and this has progressed but is not yet ready for implementation, despite the fact that it is a high priority for ICCAT. Thus, the advice coming from ICCAT scientists is to further develop the necessary data for the MSE and conduct a marginally modified 2017 stock assessment. In my view, this is a correct path and one that we have suggested to the New England Fishery Management Council Herring O/S Committee and Plan Development Team for an MSE that is presently being conducted on Atlantic herring.
As previously mentioned, the New England Fishery Management Council’s (NEFMC) Atlantic herring MSE uses inadequate and completely missing bluefin forage data. This is a dangerous and reckless process, capable of destroying one or more fishing industries off the Northeastern U.S. Coast. This is why ABTA is so deeply involved in the Council’s MSE process. The NEFMC is rushing to complete the first MSE process for the Northeast US on the basis of a Council mandate but only using forage mortality from the western bluefin biomass which ignores the forage mortality from the much larger eastern and Mediterranean bluefin migrants found in our fishery. Some estimates suggest the east biomass is 10 times larger than that of the west and mixing estimates on west Atlantic bluefin foraging grounds range from 40-75%.
The U.S. ICCAT Advisory Committee (IAC) is hosting an “Atlantic Bluefin Science Workshop” on March 21 in Ft. Lauderdale, immediately followed by the regular spring IAC meeting. ABTA will have at least 4 representatives attending this meeting