Data Zone
The site was identified as internationally important for bird conservation in 2004 because it was regularly supporting significant populations of the species listed below, meeting ('triggering') IBA criteria.
Populations meeting IBA criteria ('trigger species') at the site:| Species | Red List | Season (year/s of estimate) | Size | IBA criteria |
|---|---|---|---|---|
| Greater Scaup Aythya marila | LC | winter (2003) | present | A4i |
| Great Cormorant Phalacrocorax carbo | LC | winter (2003) | present | A4i |
| Grey Plover Pluvialis squatarola | VU | winter (2003) | present | A4i |
| Whimbrel Numenius phaeopus | LC | passage (2003) | present | A4i |
| Ruddy Turnstone Arenaria interpres | NT | passage (2003) | present | A4i |
| Sanderling Calidris alba | LC | passage (2003) | present | A4i |
| Dunlin Calidris alpina | NT | winter (2003) | present | A4i |
| Grey-tailed Tattler Tringa brevipes | LC | passage (2003) | present | A4i |
| A4iii Species group - waterbirds | n/a | winter (2003) | min 20,000 birds | A4iii |
Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2004. The most recent assessment (2015) is shown below.
| IBA conservation assessment | |||
|---|---|---|---|
| Year of assessment | State | Pressure | Response |
| 2015 | poor | high | low |
| Whole site assessed? | State assessed by | Accuracy of information | |
| no | habitat | - | |
| State (condition of the trigger species' habitats) | |||
|---|---|---|---|
| Habitat | Quantity (% remaining) | Quality (% carrying capacity) | Result |
| Marine Intertidal | good (>90%) | poor (40–69%) | poor |
| Pressure (threats to the trigger species and/or their habitats) | ||||
|---|---|---|---|---|
| Threat | Timing | Scope | Severity | Result |
| Human intrusions and disturbance | happening now | some of population/area (10–49%) | rapid decline (>30% over 3 generations) | high |
| Response (conservation actions taken for the trigger species and/or their habitats) | |||
|---|---|---|---|
| Designation | Planning | Action | Result |
| Little/none of area covered (<10%) | No management planning has taken place | Substantive conservation measures are being implemented, but these are not comprehensive and are limited by resources and capacity | low |
| Year | Protected Area | Designation (management category) | % coverage of IBA |
|---|---|---|---|
| 1974 | Tamagawa | 都道府県指定鳥獣保護区 (IV) | 1 |
| 1979 | Gyotoku | 都道府県指定鳥獣保護区 (IV) | <1 |
| 1987 | Tokyowan | 都道府県指定鳥獣保護区 (IV) | 20 |
| 1988 | Yatsu | 国指定鳥獣保護区 (IV) | <1 |
| 2003 | Common fishery right area(Chiba) | 共同漁業権区域 (VI) | 10 |
| 2006 | Tamagawa | 都道府県指定鳥獣保護区 (IV) | 1 |
| Habitat | % of IBA | Habitat detail |
|---|---|---|
| Marine Intertidal | major (>10) | |
| Marine Neritic | major (>10) |
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Inner Tokyo bay (Japan). Downloaded from
https://datazone.birdlife.org/site/factsheet/inner-tokyo-bay-iba-japan on 23/12/2024.