The distribution of submerged aquatic vegetation (SAV) in Chesapeake Bay, its tributaries, and the Maryland and Virginia coastal bays of the Delmarva Peninsula, was mapped from black and white aerial photographs. These were taken between June and October 2007, at a scale of 1:24,000, encompassing 181 flight lines.

CHESAPEAKE BAY

For 2007, 26,271 hectares (64,917 acres) of SAV were mapped in Chesapeake Bay and its tributaries.

Notable changes in SAV distribution were measured between 2006 and 2007. SAV increased 10% from 23,941 ha (59,160 ac) in 2006 to 26,271 ha (64,917 acres) in 2007.

SAV increased in two (Upper and Lower) and decreased in one (Middle) geographic zone delineated for Chesapeake Bay. In 2007, SAV increased in 31, decreased in 27, and remained unvegetated in 35 of the 93 CBP segments.

Upper Bay Zone

In the Upper Bay Zone (21 CBP segments extending south from the Susquehanna River to the Chester and Magothy rivers), SAV increased 22% from 6,286 ha (15,532 ac) in 2006 to 7,658 ha (18,922 ac) in 2007.

Six of the 21 segments increased by at least 20% and by at least 5 ha from 2006 totals:

	37%, Northern Chesapeake Bay Segment 1 (CB1TF1), 337 ha (2007) vs. 246 ha (2006)
	34%, Northern Chesapeake Bay Segment 2 (CB1TF2), 4,745 ha (2007) vs. 3,538 ha (2006)
	98%, Bush River (BSHOH), 260 ha (2007) vs. 131 ha (2006)
	137%, Gunpowder River Segment 1 (GUNOH1), 226 ha (2007) vs. 95 ha (2006)
	49%, Gunpowder River Segment 2 (GUNOH2), 367 ha (2007) vs. 246 ha (2006)
	139%, Middle River (MIDOH), 223 ha (2007) vs. 93 ha (2006)

Six of the 21 segments decreased by at least 20% and by at least 5 ha from 2006 totals.

	55%, Sassafras River Segment 1 (SASOH1), 149 ha (2007) vs. 330 ha (2006)
	92%, Sassafras River Segment 2 (SASOH2), 2 ha (2007) vs. 20 ha (2006)
	27%, Upper Central Chesapeake Bay (CB3MH), 50 ha (2007) vs. 69 ha (2006)
	81%, Patapsco River (PATMH), 4 ha (2007) vs. 19 ha (2006)
	67%, Magothy River (MAGMH), 34 ha (2007) vs. 101 ha (2006)
	63%, Lower Chester River (CHSMH), 27 ha (2007) vs. 74 ha (2006)

Three of the 21 segments remained unvegetated.

Middle Bay Zone

In the Middle Bay Zone (44 CBP segments extending south from the Bay Bridge to the Rappahannock River and Pocomoke Sound, and including the Potomac River), SAV decreased 2% from 12,407 ha (30,659 ac) in 2006 to 12,137 ha (29,992 ac) in 2007.

Four of the 44 segments increased by at least 20% and by at least 5 ha from 2006 totals:

	21%, Mouth of the Choptank River (CHOMH1), 509 ha (2007) vs. 422 ha (2006)
	23%, Manokin River Segment 1 (MANMH1), 115 ha (2007) vs. 94 ha (2006)
	100%, Lower Patuxent River Segment 1 (PAXMH1), 15 ha (2007) vs. 0 ha (2006)
	48%, Upper Potomac River (POTTF), 2,531 ha (2007) vs. 1,713 ha (2006)

Eight of the 44 segments decreased by at least 20% and by at least 5 ha from 2006 totals:

	86%, Eastern Bay (EASMH), 32 ha (2007) vs. 229 ha (2006)
	21%, Severn River (SEVMH), 132 ha (2007) vs. 166 ha (2006)
	29%, Lower Central Chesapeake Bay (CB5MH), 747 ha (2007) vs. 1,048 ha (2006)
	100%, Fishing Bay (FSBMH), 0 ha (2007) vs. 5 ha (2006)
	61%, Middle Patuxent River (PAXOH), 11 ha (2007) vs. 29 ha (2006)
	43%, Upper Patuxent River (PAXTF), 47 ha (2007) vs. 83 ha (2006)
	60%, Lower Potomac River (POTMH), 274 ha (2007) vs. 684 ha (2006)
	87%, Middle Potomac River Segment 3 (POTOH3), 39 ha (2007) vs. 293 ha (2006)

Twenty of the 44 segments remained unvegetated.

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), SAV increased 23% from 5,248 ha (12,969 ac) in 2006 to 6,476 ha (16,004 ac) in 2007.

Seven of the 28 segments increased by at least 20% and by at least 5 ha from 2006 totals:

	27%, Western Lower Chesapeake Bay (CB6PH), 160 ha (2007) vs. 126 ha (2006)
	37%, Eastern Lower Chesapeake Bay (CB7PH), 2,078 ha (2007) vs. 1,513 ha (2006)
	850%, Upper Rappahannock River (RPPTF), 30 ha (2007) vs. 3 ha (2006)
	20%, Upper Mattaponi River (MPNTF), 161 ha (2007) vs. 134 ha (2006)
	39%, Mouth of the James River (JMSPH), 81 ha (2007) vs. 58 ha (2006)
	50%, Chickahominy River (CHKOH), 427 ha (2007) vs. 286 ha (2006)
	36%, Upper James River Segment 1 (JMSTF1), 123 ha (2007) vs. 90 ha (2006)

None of the 28 segments decreased by at least 20% and by at least 5 ha from 2006 totals.

Twelve segments remained unvegetated in 2007.

DELMARVA PENINSULA COASTAL BAYS ZONE

In the Delmarva Peninsula Coastal Bays Zone (Assawoman, Isle of Wight, Sinepuxent, Chincoteague, and Southern Virginia coastal bays), SAV decreased 4% from 4,524 ha (11,1179 ac) to 4,362 ha (10,470 ac) in 2007.

Two of the five segments increased since 2006:

	133%, Southern Virginia Coastal Bays (SVCPH), 591 ha (2007) vs. 253 ha (2006)
	4%, Assawoman Bay (AAWPH), 206.57 ha (2007) vs. 199 ha (2006)

Three of the five segments decreased since 2006:

	5%, Isle of Wight Bay 138 ha (2007) vs. 145 ha (2006)
	10%, Sinepuxent Bay (SPXPH), 648 ha (2007) vs. 721 ha (2006)
	13%, Chincoteague Bay (CHNPH), 2,779 ha (2007) vs. 3,204 ha (2006)