The distribution of submerged aquatic vegetation (SAV) in Chesapeake Bay, its tributaries, and the coastal bays of the Delmarva Peninsula, was mapped from 1,820 black and white aerial photographs. These were taken between May and October 2001, at a scale of 1:24,000, encompassing 159 flight lines covering 3,343 flight line kilometers.

CHESAPEAKE BAY

For 2001, 31,520 hectares (77,855 ac) of SAV were mapped in Chesapeake Bay and its tributaries. However some portions of the Bay were not flown due to government air restrictions after the September 11 tragedy. These regions including Bush River, Gundpowder River, Middle River, Patapsco River, Magothy River, lower Chester River, Severn River, South River, Rhode River, Still Pond, Churn Creek, Worton Creek, Fairlee Creek, Swan Creek, and the middle and upper portions of the Potomac River, were not fully mapped for 2001. These regions had 4,137 ha of SAV in 2000 (10,218 ac, 15% of the 2000 total).

In order to ensure a valid analysis of change in SAV distribution and abundance given the reduced region mapped in 2001, all direct comparisons to previous years in the report are restricted to only those regions that were mapped in both years. Partial totals for 2000 have been computed for CBP segments, Bay zones, and the entire Bay using only those regions mapped for both years.

Significant changes in SAV distribution were measured between 2000 and 2001. SAV increased 28% (6,579 ha, 16,251 ac) in the regions mapped for both years. The abundance of SAV in 2001 represented 78% of the portion of the Tier I goal (set by the Chesapeake Executive Council in Directive 93-3, 1993) adjusted to only include these mapped regions (38,877 ha, 96,025 ac).

SAV increased in all three geographic zones (Upper, Middle, Lower) delineated for Chesapeake Bay In 2001, SAV increased in 34, decreased in 9, remained unvegetated in 29, and was not mapped in 6 of the 78 CBP segments (Table 6). Thirteen of the segments met the Tier I goal (Table 7).

Upper Bay Zone

In the Upper Bay Zone (17 CBP segments extending south from the Susquehanna River to the Chester and Magothy rivers), 4,840 hectares (11,955 ac) of SAV were mapped for 2001. However, portions of the zone, including Bush, Gunpowder, Middle, Patapsco, Magothy, and (lower) Chester rivers, representing 70 ha (173 ac, 28 % of Zone total) of SAV in 2000 were not mapped for 2001. Comparing the same mapped regions between 2000 and 2001, SAV increased 11% (461 ha, 1,137 ac) in 2001, exceeding the adjusted Tier I goal. Five segments in the Upper Bay Zone met the Tier I goal: CB1TF, ELKOH, BOHOH, C&DOH, and SASOH.

Four of the 17 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). These segments include:

	89%, Bohemia River (BOHOH), 143 ha (2001) vs. 76 ha (2000)
	21,958%, Upper Chesapeake Bay (CB2OH), 14 ha (2001) vs. 1 ha (2000)*
	22%, Sassafras River (SASOH), 473 ha (2001) vs. 389 ha (2000)
	100%, Lower Chester River (CHSMH), 83 ha (2001) vs. 0 ha (2000)

One of the 17 segments (or mapped portions) decreased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). These segments was:

100%, Northeast River (NORTF), 0 ha (2001) vs. 9 ha (2000)

Five of the 17 segments remain unvegetated (Table 6).

Middle Bay Zone

In the Middle Bay Zone (33 CBP segments extending south from the Bay Bridge to the Rappahannock River and Pocomoke Sound, and including the Potomac River), 17,593 hectares (43,454 ac) of SAV were mapped for 2001. However, portions of the zone, including, Severn, South, Rhode, and portions of the Potomac rivers, representing 2,449 ha (6,048 acres, 18% zone total) of SAV in 2000, were not mapped in 2001. Comparing the same mapped regions between 2000 and 2001, SAV increased 49% (5,463 ha, 13,495 ac) in 2000, comprising 79% of the adjusted Tier I goal for the Zone. Five segments in the Middle Bay Zone met the Tier I goal: LCHMH, HNGMH, PAXOH PAXTF, and POTMH.

Fourteen of the 33 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). These segments include:

	100%, Middle Central Chesapeake Bay (CB4MH), 45 ha (2001) vs. 0 ha (2000)*
	100%, Eastern Bay, (EASMH), 1,168 ha (2001) vs. 0 ha (2000)
	213%, Mouth of the Choptank River (CHOMH1), 2,129 ha (2001) vs. 681 ha (2000)
	100%, Lower Choptank River (CHOMH2), 60 ha (2001) vs. 0 ha (2000)
	105%, Little Choptank River (LCHMH), 962 ha (2001) vs. 468 ha (2000)
	100%, South River (SOUMH), 11 ha (2001) vs. 0 ha (2000)*
	42%, Lower Central Chesapeake Bay (CB5MH), 1,817 ha (2001) vs. 1,283 ha (2000)
	75%, Honga River (HNGMH), 2,002 ha (2001) vs. 1,142 ha (2000)
	22%, Big Annemessex River (BIGMH), 292 ha (2001) vs. 238 ha (2000)
	26%, Lower Pocomoke River (POCMH), 619 ha (2001) vs. 489 ha (2000)
	100%, Lower Patuxent River (PAXMH), 9 ha (2001) vs. 0 ha (2000)
	123%, Upper Patuxent River (PAXTF), 83 ha (2001) vs. 37 ha (2000)
	66%, Lower Potomac River (POTMH), 704 ha (2001) vs. 423 ha (2000)
	113%, Middle Potomac River (POTOH), 447 ha (2001) vs. 210 ha (2000)

One of the 33 segments (or mapped portions) decreased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). This segment was:

23%, Upper Potomac River (POTTF), 619 ha (2001) vs. 808 ha (2000)*

Twelve of the 33 segments remain unvegetated (Table 6).

Several segments in this zone showed a significant increase in SAV abundance, although not all of the Middle Bay Zone was fully mapped in 2001. SAV abundance in the Tangier Sound (TANMH) and Honga River (HNGMH) segments continued to increase (1,160 ha, 2,867 ac) in 2001 following the increases in 2000 (1,157 ha, 2,859 ac) and in 1999 (2,080 ha, 5,137 ac). The successive increases reverse the largest single year decline in 1998 of 1,724 hectares (4,258 ac). The Choptank River and Eastern Bay segments also had a dramatic change in 2001. The Choptank River mouth segment (CHOMH1) increased by 1,448 ha (3,576 ac) to 2,129 hectares (5,259), which reversed a 3-year decline from the 1997 peak abundance. The Eastern Bay segment (EASMH), which was devoid of SAV for the first time in the history of the aerial survey in 2000, increased by 1,168 hectares (2886 ac) in 2001.

Lower Bay Zone

In the Lower Bay Zone (28 CBP segments covering the region south from the Rappahannock River and Pocomoke Sound regions to the mouth of the Bay), 9,095 hectares (22,465 ac) were mapped for 2001. SAV increased 66% (655 ha, 1,619 ac) in 2001, comprising 66% of the Tier I goal for the Zone. Two segments in the Lower Bay Zone met the Tier I goal: JMSPH and CHKOH.

Six of the 28 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). These segments include:

	166%, Lower Rappahannock River (RPPMH), 194 ha (2001) vs. 73 ha (2000)
	46%, Corrotoman River (CRRMH), 157 ha (2001) vs. 107 ha (2000)
	65%, Upper Rappahannock River (RPPTF), 27 ha (2001) vs. 16 ha (2000)
	27%, Piankatank River (PIAMH), 218 ha (2001) vs. 171 ha (2000)
	146%, Mouth of the James River (JMSPH), 94 ha (2001) vs. 38 ha (2000)
	43%, Upper James River (JMSTF), 38 ha (2001) vs. 27 ha (2000)

Two of the 28 segments decreased by at least 20% and by at least 5 hectares from 2000 totals (Table 6). These segments were:

	20%, Upper Pamunkey River (PMKTF), 57 ha (2001) vs.70 ha (2000)
	50%, Chickahominy River (CHKOH), 108 ha (2001) vs. 216 ha (2000)

Twelve segments remain unvegetated (Table 6).

SAV increased in the Eastern Lower Chesapeake Bay (CB7PH) and Mobjack Bay (MOBPH) segments by 309 and 156 hectares (762 and 385 ac), respectively, a 12% increase over 2000 totals for each segment. The Chickahominy River segment (CHKOH) declined by 53% (108 ha, 268 ac) (Table 6).

DELMARVA PENINSULA COASTAL BAYS ZONE

In the Delmarva Peninsula Coastal Bays Zone (Assawoman, Isle of Wight, Sinepuxent, Chincoteague, and Southern Virginia Coastal Bays) 7,826 hectares (19,329 ac) were mapped in 2001. The 2001 level not only reverses the 346 hectares decrease in 2000, but also surpasses the 1999 survey high of 7,200 hectares (Table 6).

	7%, Assawoman Bay (AAWPH), 222 ha (2001) vs. 208 ha (2000)
	17%, Isle of Wight Bay (IOWPH), 124 ha (2001) vs. 106 ha (2000)
	2%, Sinepuxent Bay (SPXPH), 670 ha (2001) vs. 686 ha (2000)
	16%, Chincoteague Bay (CHNPH), 6,794 ha (2001) vs. 5,855 ha (2000)
	100%, Southern Virginia Coastal Bays (SVCPH), 16 ha (2001) vs. 0 ha (2000)

SAV was mapped for the first time in the Southern Virginia Coastal Bays segment in 2001; these beds were the result of successful restoration efforts initiated in 1997.

* Segment comparison restricted to areas mapped in both 2000 and 2001