Survey Is Fairly Useless Way To Figure Rockfish Count


Young-of-year Index Not Particularly Exact

September 15, 1991|By Capt. Bob Spore

There is nothing magical about a young-of-year (YOY) survey, nor theresults of one.

The survey is just one tool biologists use to determine the "relative abundance" of a given species. The striped bass YOY survey and index do, however, receive a great deal of press coverage.

Biologists gather lots of data, and they love to make graphs. Somewhere along the line someone noticed that the graph for the YOY striped bass survey was very similar to the graph of the annual commercial striped bass harvest.

If you superimposed one graph upon the other you would see the peaks and valleys of the YOY graph two years before corresponding peaks and valleys of the commercial harvest. This was back when a legal striped bass or rockfish was only 12 inches and it took 18 months to two years to grow a legal rockfish.

The YOY survey and resulting index became very important during the striped bass moratorium. The Atlantic States Marine Fisheries Commission, made up of representatives from Maine to North Carolina, controls the striped bass fishery for this area.

The commission has no power itself, but its striped bass management plan is backed up by federal law that could close the striped bass fishery in a member state should it not be in compliance with the plan.

The ASMFC said that a three-year, rolling index of 8 was required to lessen the severe restrictions placed on striped bass fishing from Maine to North Carolina beginningin 1985. In Maryland, these restrictions amounted to a moratorium.

The YOY index was never designed to give an accurate representationof the year class strength. It is a quick and dirty means to measurethe "relative abundance" of the young striped bass year class.

The index was, however, the only scientific tool on the whole East Coast that the ASMFC felt it could use to indicate increased striped basspopulation.

By early 1989, ASMFC officials were getting worried. Maryland's YOY index had come nowhere near 8. Officials in several states were very unhappy about the restrictions, especially because thenumber of striped bass was obviously increasing, and ASMFC had no means of measuring the increase.

In August 1989, Maryland announced a super year-class and an index that permitted ASMFC to breathe a sigh of relief and open up the fishery for a very modest harvest.

By the way, the existing management plan requires Maryland to adjust itsharvest based on the YOY indexes but makes no reference to closing the fishery based upon low YOY annual indexes.

The 1991 YOY index doesn't mean much. The survey, by design, will tell you if you have a very good or a very poor year-class. The results are not accurate enough to differentiate between an index of 3 or 6, for example.

Thisyear was not a great year, but it wasn't a bust year either. We are still producing many more times rockfish than we are catching.

A related issue that doesn't receive sufficient press is Maryland's striped bass hatchery program. Maryland has stocked approximately 1 million 4- to 9-inch striped bass each year for the last four or five years.

Many biologists believe that this program should boost the index. That is, if the index is 4.8, when you add in the hatchery programthe index should be at least 5.8.


I know the letter-writing gods are going to rain all over me, but something ought to be done about the Chesapeake Bay Foundation.

The chairman of the Striped Bass Advisory Board is a biologist for the CBF. He voted with other board members to recommend that Maryland expand its spring striped bass fishery to run all of May and drop the minimum size for striped bass from 36 inches this year to 32 inches next year.

The 1991 spring fishery accounted for a total of only 140 legal striped bass for thousands and thousands of fishing hours.

Now the CBF has written a letter to the ASMFC recommending that fisheries, including Maryland's, not be expanded.

I would have thought that having taken a beating over its oyster program, the CBF would stay in the habitat-improvement programs -- where it belongs -- and out of fishery management proposals, where it has zero credibility or less.

Every time I turned around, Larry Simns, president of the Maryland Waterman's Association, was taking another pound of CBF flesh over the foundation's proposed oyster moratorium.

Maybe the CBF coffers are running a little low and they run these folks out to rattle sabers and cry wolf for attention. I do know that the CBF credibility is at an all-time low.

It'sa shame, too; I used to like some of those people.

Bob Spore is aCoast Guard-licensed charter boat captain from Pasadena. His Outdoors column appears every Friday and Sunday in the Anne Arundel County Sun.

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