Black Sea Bass Stock Assessment Update 6 Things To Know

July 2010

1. How do we assess the population?

The limited information on black sea bass was integrated into a useful mathematical model called a statistical catch at length model (SCALE). Using this framework, the population is modeled, much as the U.S. Census Bureau models human populations using similar data—population size at age, growth rates, age at maturity, reproductive potential and success, life span, and removals by deaths. This black sea bass stock assessment model uses widely-accepted and commonly-used fishery science principles to analyze the population size. The data used have been collected annually since 1968 from fish caught (recreational (since 1981) and commercial) and fish sampled in the ocean (taken on research surveys). Information from a tagging study and age data led to the conclusion that natural mortality was higher than previously modeled. Additionally, the interpretation of historical landings concluded that landings taken in the 1950s were not at sustainable levels.

2. Is black sea bass no longer considered a data poor stock?

No. Despite the applied modeling approach (SCALE) which better integrates limited information to analyze the black sea bass population, it is still considered a “data poor” stock. There are still gaps in critical life history information for black sea bass life and the current sampling gear may not be optimal to assess the population; these issues will need to be addressed through improved data collection and fish sampling programs and research.

3. How do we "check" the models?

By conducting a peer review of the assessment such as the December 2008 Northeast Data Poor Stocks Peer Review for black sea bass. A working group of fishery scientists conducts a thorough evaluation of available data, methods and models, and selects those that best represent the black sea bass population. This work is then “peer reviewed” by a group of independent experts. The peer reviews have validated assessment results and helped improve stock assessment methods and modeling. Stock assessment updates are conducted in the years between peer reviews. Updates include the most recent data, but apply the exact same methods that were validated by the peer-review. The 2011 stock assessment update included data through 2010

4. Is the black sea bass stock rebuilt?

The December 2008 data poor stock peer review set the rebuilding goal as 27.6 million pounds of spawning stock biomass. The stock exceeded the goal in 2003 and 2004; therefore it is no longer under a rebuilding program. The most recent stock assessment update indicated that the 2010 spawning stock size is about 111% of the biomass goal.

5. Are we overfished or overfishing?

No, the stock is not considered overfished and is not currently experiencing overfishing based on a review of the most recent year’s data (2010) in the stock assessment update.

6. Have harvest quotas and limits been set too low in the past?

No. The quotas and limits have been set consistent with the scientific advice. The Data Poor Stocks Peer Review Panel recommended that, “the Science and Statistical Committee recognize and allow for the sizable uncertainty in stock status when establishing catch limits”. 

Scup Stock Assessment Update 5 Things To Know

July 2010

1. How do we assess the population?

The information on scup was integrated into a useful mathematical model called an age-structured assessment program (ASAP). The population is modeled, much as the U.S. Census Bureau models human populations using similar data— population size at age, growth rates, age at maturity, reproductive potential and success, life span, and removals by deaths. This scup stock assessment model uses widely-accepted and commonly-used fishery science principles to analyze the population size. The data used have been collected annually since 1963 from fish caught (recreational (since 1981) and commercial) and fish sampled in the ocean (taken on research surveys.) A simpler assessment approach was used in the past because the analytical models (like ASAP) did not work well when they were attempted previously. The ASAP model utilizes more sources of information on scup which indicate age-structure and recruitment have improved in recent years.

2. How do we "check" the models?

By conducting a peer review of the assessment such as the December 2008 Northeast Data Poor Stocks Peer Review for scup. A working group of fishery scientists conducts a thorough evaluation of available data, methods and models, and selects those that best represent the scup population. This work is then “peer reviewed” by a group of independent experts. The peer reviews have validated assessment results and helped improve stock assessment methods and modeling. Stock assessment updates are conducted in the years between peer reviews. Updates include the most recent data, but apply the exact same methods that were validated by the peer-review. The 2010 stock assessment update included data through 2009.

3. Is the scup stock rebuilt?

The December 2008 data poor stock peer review set the rebuilding goal as 203 million pounds of spawning stock biomass. The stock is no longer under a rebuilding program because the spawning stock biomass exceeded the rebuilding goal in the most recent five years, 2004-2009. The most recent stock assessment update indicated that the 2009 spawning stock size is about 170% of the biomass goal.

4. Are we overfished or overfishing?

No, the stock is not considered overfished and is not currently experiencing overfishing.

5. Have harvest quotas and limits been set too low in the past?

No. The quotas and limits have been set consistent with the scientific advice. The Data Poor Stocks Peer Review Panel stated that, “rapid increases in quota to meet the revised MSY [maximum sustainable yields] would be unwarranted given uncertainties in recent recruitments” and, “a more gradual increase in quotas is a preferred approach reflective of the uncertainty in the model estimates and stock status”.

Summer Flounder Stock Assessment Update: 6 Things To Know

July 2010

1. How do we assess the population?

The information on summer flounder was integrated into a useful mathematical model called an age-structured assessment program (ASAP). The population is modeled, much as the U.S. Census Bureau models human populations using similar data—population size at age, growth rates, age at maturity, reproductive potential and success, life span, and removals by deaths. The summer flounder stock assessment model uses widelyaccepted and commonly-used fishery science principles to analyze the population size. The data used have been collected annually since 1982 from fish caught (recreational and commercial) and fish sampled in the ocean (taken on research surveys.)

2. How do we "check" the models?

By conducting a benchmark assessment such as the June 2008 Stock Assessment Workshop (SAW/SARC 47) for summer flounder. A working group of fishery scientists conducts a thorough evaluation of available data, methods and models, and selects those that best represent the summer flounder population. This work is then “peer reviewed” by a group of independent experts. The summer flounder assessments have been peer reviewed 17 times in the last 26 years. The peer reviews have validated assessment results and helped improve stock assessment methods and modeling. Stock assessment updates are conducted in the years between peer reviews. Updates include the most recent data, but apply the exact same methods that were validated by the peer-review. The 2010 stock assessment update included data through 2009.

3. Is the summer flounder stock rebuilt?

The June 2008 Stock Assessment Workshop (SAW/SARC 47) set the rebuilding goal as 132 million pounds of spawning stock biomass. The most recent stock assessment update indicates that the current spawning stock size is about 89% of the biomass goal, and that rebuilding can occur on schedule (by Jan. 1, 2013), given continued success in staying at or below annual commercial quotas and recreational harvest limits.

4. Have rebuilding targets been set too high in the past?

No, but since 1999 the rebuilding targets have been declining. None, however, has ever been achieved. Targets often change over time as fishery scientists improve models and methods, and as new data are available on how the stock responds (grows, produces young, dies) to ecosystem conditions and fishing rules intended to end overfishing and rebuild the stock.

5. Are we overfished or overfishing?

No, but the stock is not yet rebuilt and fishing harvests need to stay within the annual limits to ensure that it will be. 6. Have harvest quotas and limits been set too low in the past? No. The quotas and limits have been set consistent with the scientific advice, and have been exceeded in most years since 1982. Overfishing was occurring from 1982-2006; however it was not occurring in the three most recent years 2007 - 2009. The most recent stock assessment update suggests that initial quotas and limits for 2011 may be set slightly higher than those in 2010 without compromising rebuilding goals if 2010 quotas and limits are not exceeded.