Menhaden Report   

by Ed Cherry

(from Jersey Coast Anglers Association September 2002 Newsletter)

 

The ASMFC Menhaden Advisory Panel met on July 10, 2002 in Warwick, RI for the purpose of reviewing the draft version of Amendment 2 for the Management of Atlantic Menhaden.

The primary areas of discussion revolved around the status of the stock, status of the fishery and status of assessment advice.

 

The status of the stock is considered to be healthy with 9 age classes represented in 2001. The Technical Committee said although the overall fishery was not over fished, warned that this could change very quickly due to a lack of 0-1 age fish over the past two years. This occurred even though the SSB (Spawning stock biomass = total weight of fish which are sexually mature; generally pertaining only to females) was continuing to grow and is at acceptable levels. This situation has only existed on one other occasion in the past 50 years.

 

There is currently no evidence to suggest that over fishing has caused poor recruitment. Overall, there is some other underlying factor thought to influence recruitment. Quantifying the controlling factor(s) will be difficult. The SSB is currently above the target (Amendment 1 and newly proposed value).

 

 Additional data indicates severe over fishing of the Chesapeake Bay area. Concern was raised by some reduction industry people, with the closure of New Jersey inshore waters, that the Chesapeake over fishing would get worse. The lack of 0-1 age menhaden in the Virginia area is seriously impacting the foraging habits of Striped Bass and Weakfish. Although the Chesapeake area is small with comparison to the stock’s total coastal range, it is responsible for 40-45% of the reduction landings, and an additional 5% is landed in the bait category by weight. The entire reduction fishery utilizes 83% of the stock.

 

The bait category is growing and now consists of 17% of the total commercial catch. The principle areas for the bait fishery are New Jersey and Virginia. It was felt that accurate records are needed from the bait industry in order to evaluate its impact on the stocks.

 

Due to processing plant consolidation, reduction of the Virginia fleet from 20 to 13 vessels and adverse weather, the harvest was reduced for 2000 and 2001 about 36% below the average for the previous 5 years. However, the North Carolina boats continue to use a smaller mesh size and target juvenile fish unlike the Virginia boats that look for age 2 and above. These older fish give a higher yield of fish meal and oil.

 

A discussion on the Multi Species Model showed a high degree of promise to this approach. What is needed is more data on the Bluefish from 1999 to the present time. Currently the model includes the best available input data. This model currently focuses on the process of controlling menhaden mortality, not the absolute numbers. It includes the interactions with three major predators (Striped Bass, Weakfish and Bluefish) and the fishery, and their effects on menhaden population, particularly at early ages, resulting from predation and fishing mortality. The strength of the multi species model lies in the demonstration of the capability to incorporate multi species information into the assessment framework and quantifying previously subjective measures of natural predation and mortality. As with any other new assessment methodology, this should be considered additional information to the official model until the multi species model is peer reviewed and deemed appropriate.

 

Due to the decline in reduction fishery landings coupled with increased and improved reporting of the bait fishery landings, the relative importance of the bait fishery landings has increased. Using the combined reduction and bait fishery data would remove any bias inherent in relying on the reduction fishery data only and provide a more accurate picture of the total menhaden population.

 

As a result of this recommendation, new biological reference points based on the combined data have been calculated (see below). The Technical Committee recommends that the Management Board adopt these new reference points for managing the Atlantic menhaden resource

 

Reference Point	"Old"	"New"	Stock Status
Fishing Mortality Target (F target)	1.04	0.9	0.6
FishingMortality Threshold (F threshold)	1.33	1.1
SpawningStock BiomassTarget (SSB target)	37,400 mt	50,000 mt	90,100 mt
SpawningStock BiomassThreshold (SSB threshold)	20,570 mt	27,500 mt

 

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