The distribution of submerged aquatic vegetation (SAV) in Chesapeake Bay, its tributaries, and the coastal bays of the Delmarva Peninsula, was mapped from 2,324 black and white aerial photographs. These were taken between June and November 2002, at a scale of 1:24,000, encompassing 193 flight lines covering 4,318 flight line kilometers.
CHESAPEAKE BAY
For 2002, 36,283 hectares (89,659 ac) of SAV were mapped in Chesapeake Bay and its tributaries. This represents 48% of the 2010 Restoration goal (74,850 ha, 184,963 ac) set by the Chesapeake Executive Council in Directive 93-3 which was revised in 2003.
Because portions of the Bay were not mapped in 2001 due to government air restrictions after the September 11 tragedy, all direct comparisons to analyze change in SAV distribution and abundance between 2001 and 2002 are restricted to only those regions that were mapped in both years. Partial totals for 2002 have been computed for CBP segments, Bay zones, and the entire Bay using only those regions mapped for both years. For segments not mapped in 2001, 2002 data are compared with totals from 2000.
Significant changes in SAV distribution were measured between 2001 and 2002 even though the bay was not fully mapped in 2001. SAV increased 8% from 30,430 hectares (75,196 ac) in 2001 to 32,954 hectares (81,433 ac) in 2002 in regions mapped for both years.
SAV increased in two (Middle, Lower) and decreased in one (Upper) geographic zones delineated for Chesapeake Bay. In 2002, SAV increased in 34, decreased in 19, and remained unvegetated in 25 of the 78 CBP segments (Table 6). Eleven of the segments met the 2010 Restoration 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), 5,328 hectares (13,166 ac) of SAV were mapped for 2002 comprising 56% of the 2010 Restoration goal. Comparing the same mapped regions between 2001 and 2002, SAV declined from 4,770 hectares (11,787 ac) in 2001 to 4,433 hectares (10,955 ac) in 2002. Four segments in the Upper Bay zone met the 2010 Restoration goal: BOHOH, CB2OH, SASOH, and BSHOH.
Four of the 17 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments include:
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100%, Northeast River (NORTF), 31 ha (2002) vs. 0 ha (2001) |
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80%, Bush River (BSHOH), 142 ha (2002) vs. 79 ha (2000)*** |
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926%, Upper Central Chesapeake Bay (CB3MH), 38 ha (2002) vs. 4 ha (2000) *** |
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132%, Magothy River (MAGMH), 84 ha (2002) vs. 36 ha (2000) ** |
Five of the 17 segments (or mapped portions) decreased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments were:
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79%, Elk River (ELKOH), 176 ha (2002) vs. 823 ha (2001) |
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62%, Bohemia River (BOHOH), 55 ha (2002) vs. 143 ha (2001) |
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29%, Sassafras River (SASOH), 336 ha (2002) vs. 473 ha (2001) |
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81%, Gunpowder River (GUNOH), 187 ha (2002) vs. 985 ha (2000)** |
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15%, Middle River (MIDOH), 255 ha (2002) vs. 300 ha (2000)** |
Three of the 17 segments remained unvegetated (Table 6).
SAV increased by 16% from 3,230 hectares (7,983 ac) in 2001 in the Northern Chesapeake Bay segment (CB1TF) to 3,734 ha (9,227 ac), the highest level mapped in this segment.
Middle Bay Zone
In the Middle Bay Zone (34 CBP segments extending south from the Bay Bridge to the Rappahannock River and Pocomoke Sound, and including the Potomac River), 21,437 hectares (52,973 ac) of SAV were mapped for 2002, comprising 46% of the 2010 Restoration goal. Comparing the same mapped regions between 2002 and 2001, SAV increased 15% from 16,565 (40,934 ac) in 2001 to 19,003 (46,958 ac) in 2002. Three segments in the Middle Bay Zone met the Restoration 2010 goal: PAXTF, MATTF, and ANATF .
Eleven of the 34 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments include:
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140%, Middle Central Chesapeake Bay (CB4MH), 109 ha (2002) vs. 45 ha (2001)* |
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25%, Mouth of the Choptank River (CHOMH1), 2,665 ha (2002) vs. 2,129 ha (2001) |
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22%, Little Choptank River (LCHMH), 1,176 ha (2002) vs. 962 ha (2001) |
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120%, Severn River (SEVMH), 114 ha (2002) vs. 0 ha (2000)*** |
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28%, Honga River (HNGMH), 2,558 ha (2002) vs. 2,002 ha (2001) |
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1,856%, Fishing Bay (FSBMH), 44 ha (2002) vs. 2 ha (2001) |
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80%, Manokin River (MANMH), 295 ha (2002) vs. 163 ha (2001) |
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542%, Lower Patuxent River (PAXMH), 57 ha (2002) vs. 9 ha (2001) |
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51%, Lower Potomac River (POTMH), 1,060 ha (2002) vs. 704 ha (2001) |
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140%, Mattawoman Creek (MATTF), 321 ha (2002) vs. 134 ha (2000)** |
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98%, Piscataway Creek (PISTF), 256 ha (2002) vs. 129 ha (2000)** |
Two of the 33 segments (or mapped portions) decreased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments were:
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80%, Middle Patuxent River (PAXOH), 9 ha (2002) vs. 42 ha (2001) |
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87%, Middle Potomac River (POTOH), 57 ha (2002) vs. 447 ha (2001)* |
Eleven of the 33 segments remained 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 from a combined total of 7,390 hectares mapped in 2001 to 8,637 hectares in 2002. These segments have had successive increases since 1999. The Manokin River segment (MANMH) increased 80% from 163 hectares (404 ac) in 2001 to 295 hectares (728 ac) in 2002. The Choptank River and Eastern Bay segments also had a dramatic change in 2001. The Choptank River mouth segment (CHOMH1) increased 25% from the 2001 level of 2,129 hectares (5,260 ac) to 2,665 hectares (6,585 ac) mapped in 2002. This follows the 2001 increase from the 2000 level of 681 hectares (1,682 ac). The Eastern Bay segment (EASMH), which increased by 1,168 hectares (2,887 ac) in 2001 decreased by 43 ha ( 107 ac) in 2002 to 1125 hectares (2780 ac). The Lower Patuxent River segment (PAXMH) increased to 57 hectares (141 ac) in 2002 from the 9 hectares (22 ac) mapped in 2001. The Middle and Upper Patuxent River (PAXOH) and (PAXTF) segments decreased by 80% from 42 hectares (104 ac) to 9 hectares (21 ac) and by 17% from 83 hectares to 69 hectares respectively.
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), 9,518 hectares (23,519 ac) were mapped for 2002. SAV increased 5% (422 ha, 1,044 ac) in 2002, comprising 51% of the 2010 Restoration goal for the Zone. Four segments in the Lower Bay Zone met the 2010 Restoration goal: CRRMH, PMKTF, JMSOH , and CB8PH.
Six of the 28 segments (or mapped portions) increased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments include:
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110%, Lower Rappahannock River (RPPMH), 407 ha (2002) vs. 194 ha (2001) |
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98%, Corrotoman River (CRRMH), 311 ha (2002) vs. 157 ha (2001) |
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30%, Piankatank River (PIAMH), 284 ha (2002) vs. 218 ha (2001) |
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100%, Upper Mattaponi River (MPNTF), 9 ha (2002) vs. 0 ha (2001) |
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22%, Upper Pamunkey River (PMKTF), 69 ha (2002) vs. 57 ha (2001) |
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20%, Mouth of the James River (JMSPH), 113 ha (2002) vs. 94 ha (2001) |
Two of the 28 segments decreased by at least 20% and by at least 5 hectares from 2001 totals (Table 6). These segments were:
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95%, Upper Rappahannock River (RRPTF), 1 ha (2002) vs. 27 ha (2001) |
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30%, Chickahominy River (CHKOH), 75 ha (2002) vs. 108 ha (2001) |
Eleven segments remain unvegetated (Table 6).
SAV continued to increased in the Eastern Lower Chesapeake Bay (CB7PH) by 7%, from 3,712 hectares mapped in 2001 to 3,966 hectares (9,801 ac) but the Mobjack Bay (MOBPH) segment declined 8% from 3,850 hectares (9,513 ac) mapped in 2001 to 3,538 hectares (8,743 ac) mapped in 2002. This is the first decline in the Mobjack Bay segment since 1998. The Chickahominy River segment (CHKOH) declined for a second year by 30% in 2002 as 75 hectares (186 ac) were mapped in 2002 compared to 108 hectares (268 ac) mapped in 2001 (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) 7,319 hectares (18,087 ac) were mapped in 2002, a 6% (507 ha, 1,253 ac) decrease from the 2001 level of 7,826 hectares (19,340 ac). The 2002 level is the first decrease for the zone since 2000 (Table 6).
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25%, Assawoman Bay (AAWPH), 167 ha (2002) vs. 222 ha (2001) |
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25%, Isle of Wight Bay (IOWPH), 93 ha (2002) vs. 124 ha (2001) |
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11%, Sinepuxent Bay (SPXPH), 743 ha (2002) vs. 670 ha (2001) |
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8%, Chincoteague Bay (CHNPH), 6,235 ha (2002) vs. 6,794 ha (2001) |
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415%, Southern Virginia Coastal Bays (SVCPH), 82 ha (2002) vs. 16 ha (2001) |
The SAV mapped in the Southern Virginia Coastal Bays segment were the result of successful restoration efforts initiated in 1997.
* Segment comparison restricted to areas mapped in both 2002 and 2001
** Segment comparison of 2000 and 2002 where 2001 was not mapped
*** Segment comparison of 2000 and 2002 where no quadrangle was fully mapped for this segment in 2001