ARE STRIPED BASS IN GOOD SHAPE?
Submitted by Ted Williams on Mon, 03/20/2006 - 10:23.
ARE STRIPED BASS IN GOOD SHAPE? The 2004 stock assessment says so, but… By Captain John McMurray Striped bass are exceptionally important to New York and New Jersey anglers and the businesses that they support. That’s why many of us raised our eyebrows back in the fall of 2004 when the Atlantic States Marine Fisheries Commission (ASMFC) released its 2003 striped bass stock assessment. The method the ASMFC uses to gauge the health of the striped bass stock – the virtual population analysis (VPA) - showed that larger, older striped bass (ages 7 to 11 - fish in the 10-plus-pound range) were being drastically overfished along the coast. According to the report, the kill rate for these larger fish was 150% above the overfishing threshold (the point at which the ASMFC requires that corrective action be taken to curb mortally). The numbers further indicated that the largest, oldest fish - those fish most would label a “trophy” - were experiencing the highest mortality rate. The report further suggested that these big breeders had been heading downward for several years before 2003. While this was unsettling, to me it wasn’t much of a surprise. A trip down to any local marina in the spring or the fall of 2003 and 2004 provided ample, although anecdotal, evidence that these bigger fish were in fact being caught in large numbers. Add to all of this the fact that the illegal striped bass “poaching” industry in New York appeared to be having a banner two years and one can begin to see the problem that the larger older striped bass are facing. However, the estimated increase in mortality and decrease in spawning fish contained in the 2003 ASMFC assessment was so dramatic, particularly when compared to previous years, that members of the ASMFC Technical Committee questioned the accuracy of the findings. Conversely, tagging data which was previously considered less reliable than the population model indicated that the kill rate was just a hair over target and under the overfishing threshold. The ASMFC’s Striped Bass Management Board decided that, based on the conflicting nature of the two reports, and based on the indecisive guidance provided by the Technical Committee, overfishing of larger fish may not have occurred. While some would have preferred that the ASMFC had taken some precautionary measures back then, it decided to wait another year to see if the 2004 stock assessment confirmed the overfishing of the older larger bass. New York was given permission at the meeting to increase their bag-limit from one to two fish. This was later instituted in the form of a 40-plus-inch “trophy” fish through “emergency-regulation.” Because those numbers in the 2004 ASMFC report reflected the 2003 catch, they didn’t take into account the 2004 liberalization in regulations that came after Amendment 6 to the striped bass management plan was adopted, such as a 40% increase in commercial quota and a decision by Massachusetts, the largest recreational harvester on the coast, to increase anglers’ bag limit from one to two fish. Many folks in the angling community were fairly certain that the number of larger, older bass killed in 2004 would be far greater than it was in 2003, and that it would probably force ASMFC to take action and quell what appeared to many to be an unsustainable harvest. But, that’s not quite what happened. Enter the 2004 Striped Bass Stock Assessment On October 31, 2005 the 2004 Stock Assessment was released at the ASMFC Striped Bass Management Board meeting. Apparently, the VPA formula that was used during prior years to estimate the number of fish killed by anglers was abruptly changed by the ASMFC. Under the new formula, the mortality on the larger older stripers was now conveniently just a hair below the threshold for corrective action. The new formula dramatically changed the estimates for both 2003 and 2004 fishing mortality. Under the old VPA model the 2004 fishing mortality would have been way over the threshold for corrective action as many expected that it would be. Dropping a few previously used indices (items of statistical input) from the model immediately caused the mortality and population estimates of both last year and this year to change in a way that put the ASMFC’s management of the species in a much more favorable light. According to Gary Shepard at the NOAA Fisheries NE Fisheries Science Center there was a workshop held in April to re-examine all the indices used in the assessment and determine if there was a statistically valid basis for each index. The reason for adding or dropping indices varied depending on the index. But, the difference in outcomes once these indices were dropped was so dramatic that a number of people in the angling and science communities doubted the accuracy of the new model. Quite a few others are accepting the generally accuracy of the model, but asking whether sufficient caution is being used when interpreting the results. The statement was made and written into the assessment that there was disagreement reported in the technical committee over these estimates, but no more detail was provided. It’s important to note here that all these changes in the VPA model have not yet been peer reviewed, and are not scheduled to be for almost two years. Because of the questions regarding the validity of the new VPA at the ASMFC meeting, Maine asked to have the peer review timing moved up. But, in a close vote, the motion failed. Even with all of this uncertainly, the ASMFC didn’t miss the chance to pat themselves on the back claiming in a press release “Scientific advice presented to the Commission’s Atlantic Striped Bass Management Board indicates that striped bass management under amendment 6 to the interstate management plan continues to be a success.” However, even with the very significant changes in the stock assessment caused by the adoption of the revised model, anglers are still on the brink of overfishing those 7-year-plus striped bass, and about 30% above the target fishing mortality established in Amendment 6 to the Striped Bass Management Plan. In addition, the 2004 stock assessment report pointed out that the number of fish killed was up 33% from 2003. However, because the morality level is still below the threshold, the ASMFC is not required to take any action, and so will continue to maintain the status-quo. According to Stripers Forever President Brad Burns, who attended the ASMFC Striped Bass Management Committee meeting, Mark Gibson from RI, who was once chair of the ASMFC striped bass scientific committee, expressed concern about the harvest of mature fish being too close to the overfishing threshold to provide a reasonable margin for error. New York ASMFC commissioner Gordon Colvin added that he was not convinced that the Management Board shouldn’t be talking about serious conservative changes to striped bass management. A number of folks in the angling community suspect that the change in the VPA model was the result of the ASMFC feeling pressure to protect their image and the accuracy of the management plans they had created in the past. Regardless, given that the new stock assessment’s numbers still indicate we are so close to overfishing larger older fish, and given the well known fact that there is a lot of variability and uncertainty in any estimate derived from the VPA, one would hope that the ASMFC would prefer to error on the side of conservation. However, historically this hasn’t been the case. Unfortunately, pressure from both the angling and commercial fishing lobbies effect the decisions that the fishery managers make. What to expect in 2006 The Stripers Forever survey released last December showed that its members were catching smaller and fewer striped bass during the 2005 season than in prior years, and my guess is that trend will continue in 2006. While that is speculative, one thing is for certain; the number of old, larger breeders being harvested is increasing dramatically each year. Can the stock keep up with this kind of mortality? The fact that I’m seeing less and less large bass each year on my charters leads me to believe that it can not, and I would urge the ASMFC to take a closer look at bass in 2006, and perhaps make some hard choices. My charter business caters to saltwater flyfishers and light tackle anglers; hence my anecdotal data applies to them. Those who fish with bait or even plugs may disagree with my assessment, but flyrodders are the proverbial canaries-in-the-coal-mine. Because the technique we use makes it harder to catch large fish, we are the first to see the effects of a decline. I would hope folks heed our warning.