DNR nets record high juvenile rockfish Recovery of fishery called 'great news'

OUTDOORS

September 18, 1993|By Peter Baker | Peter Baker,Staff Writer

Maryland's juvenile index of striped bass for 1993 was announced yesterday by the Department of Natural Resources, and the findings of the netting survey established a record high number.

"This is not good news, it is great news," James Peck, assistant secretary of DNR, said yesterday in Annapolis. "We have a record highest striped bass juvenile index of 39.6, and it is significantly higher than the previous record in 1970, which was 30.4.

"That can only be categorized as great news for the striped bass recovery."

The juvenile index is a measurement of annual spawning success in Maryland waters and has been used to predict the abundance or scarcity of striped bass in the fishery since 1954.

In 1983, two years before Maryland enacted a moratorium on the threatened striped bass (rockfish), the juvenile index was 1.4. The index did not get above 4.8 until 1989, when it reached 25.2 and triggered the reopening of a limited fishery in 1990.

"This [1993] is a dominant year class," Peck said, a year class in which there are so many fish that it will sustain "the fishery and the reproduction -- if they are properly protected -- for a number of years."

The last dominant year class was 1970.

Although the 1989 index was high enough to achieve a minimum three-year average of 8.0 and trigger the reopening of the fishery, the validity of the 25.2 index often has been questioned.

"There was a little bit of controversy in that [1989] because the result was significantly influenced by one high seine haul in the Choptank River at Hambrooks bar," Peck said.

In this year's survey, the total of 132 hauls of a seine net at 22 sites in major rockfish nursery areas in Maryland's Chesapeake Bay and tributaries produced record or very strong results across the board.

The major nursery areas for rockfish are the Potomac River, Nanticoke River, Choptank River and the head of the Chesapeake Bay.

"The important factor here is that it is system-wide to make it a dominant year class," Peck said. "The Potomac is by far a record high after a good year last year. In the Choptank, another high record year, even larger than 1989.

"The upper bay and the Nanticoke show higher index values than at any time since the 1972-1973 indexes."

DNR biologists said that increased numbers of fish on the spawning grounds this spring and favorable weather conditions are largely responsible for the success of the spawn.

The spawn was so successful throughout Maryland's tidewater that juvenile rockfish have been found in the Choptank as far upriver as Greensboro, in the Chester River as far upstream as Millington and in the Patapsco and other rivers that are not part of the juvenile survey.

To get the annual index, DNR personnel go to each of 22 sites in prime nursery areas once a month during July, August and September and make two passes with a seine. With each haul of the net, the young of the year are counted.

This year the 132 hauls captured 5,229 juvenile rockfish. After corrections for hatchery fish in the Nanticoke hauls, the average per haul was found to be 39.6.

YOUNG OF THE YEAR INDEX

The juvenile striped bass survey has been a measure of abundance or scarcity of rockfish in Maryland waters since 1954. This year, the index shows a dominant year class, one that apparently is large enough to sustain and perpetuate the species through possible spawning failures for several years to come. The last dominant year class was in 1970 (30.4) and the long-term average has been 8.0. The following table follows the rise and fall of year classes during the past 24 years.

. .. ..Head of .. ..Potomac .. ..Choptank .. ..Nanticoke .. ..Overall

Year ..the bay .. ...River .. .. ..River .. .. ..River .. .. .average

1970 .. .33.1 .. .. ..20.1 .. .. ..57.2 .. .. .. .17.1 .. .. ...30.4

1971 .. .23.7 .. .. ...8.5 .. .. ...6.3 .. .. .. ..2.0 .. .. ....7.2

1972 .. .12.1 .. .. ...1.9 .. .. ..11.0 .. .. .. .25.0 .. .. ...11.0

1973 .. .24.7 .. .. ...2.1 .. .. ...1.0 .. .. .. ..1.1 .. .. .. .8.9

1974 .. .19.9 .. .. ...1.5 .. .. ..15.3 .. .. .. ..3.9 .. .. ...10.1

1975 .. ..7.6 .. .. ...7.8 .. .. ...4.7 .. .. .. ..5.2 .. .. ....6.7

1976 .. ..9.8 .. .. ...3.2 .. .. ...2.4 ... .. .. .1.7 ... .. ...4.9

1977 .. .12.1 .. .. ...1.9 .. .. ...1.2 .. .. .. ..1.0 .. .. ....4.8

1978 .. .12.5 .. ... ..7.9 .. .. ...6.0 .. .. .. ..4.8 .. .. .. .8.5 C 1979 .. ..8.3 .. .. ...2.2 .. .. ...2.8 .. .. .. ..0.9 .. .. .. .4.0

1980 .. ..2.3 .. .. ...2.2 .. .. ...1.0 .. .. .. ..1.8 .. .. .. .2.0

1981 .. ..0.3 .. .. ...1.4 .. .. ...1.3 .. .. .. ..2.4 .. .. .. .1.2

1982 .. ..5.5 .. .. ..10.0 .. .. ..13.0 .. .. .. ..6.2 .. .. ....8.4

1983 .. ..1.2 .. .. ...2.0 .. .. ...0.9 .. .. .. ..1.0 .. .. .. .1.4

1984 .. ..6.1 .. .. ...4.7 .. .. ...2.8 .. .. .. ..1.5 .. .. .. .4.2

1985 .. ..0.3 .. .. ...5.6 .. .. ...3.7 .. .. .. ..2.1 .. .. .. .2.9

1986 .. ..1.6 .. .. ...9.9 .. .. ...0.5 .. .. .. ..2.2 .. .. .. .4.1

1987 .. ..0.3 .. .. ...6.4 .. .. ..12.1 .. .. .. ..2.5 .. .. ....4.8

1988 .. ..7.3 .. .. ...0.4 .. .. ...0.7 .. .. .. ..0.4 .. .. .. .2.7

1989 .. .19.4 .. .. ...2.2 .. .. ..97.8 .. .. .. ..2.9 .. .. ...25.2

1990 .. ..3.8 ... .. ..0.6 .. .. ...3.1 .. .. .. ..0.9 .. .. .. .2.1

1991 .. ..3.9 .. .. ...2.5 .. .. ..12.2 .. .. .. ..1.1 ... .. ...4.4

1992 .. ..1.3 .. .. ..22.1 .. .. ...4.3 .. .. .. ..4.3 .. .. .. .9.0

1993 .. .23.0 .. .. ..36.2 .. .. .105.5 .. .. .. ..8.9 .. .. ...39.6

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