Rusty Axinopsid
- Peak month
- January
- Records since 2000
- 680
- Scientific name
- Mendicula ferruginosa
Capped Orb Mussel
- Peak month
- May
- Records since 2000
- 671
- Scientific name
- Musculium lacustre
Celtic sea slug
- Peak month
- September
- Records since 2000
- 668
- Scientific name
- Onchidella celtica
Common Pelican's Foot
- Peak month
- September
- Records since 2000
- 662
- Scientific name
- Aporrhais pespelecani
Three-toothed Moss Snail
- Peak month
- May
- Records since 2000
- 661
- Scientific name
- Azeca goodalli
Smooth blind shell
- Peak month
- August
- Records since 2000
- 650
- Scientific name
- Caecum glabrum
Hermania scabra
- Peak month
- October
- Records since 2000
- 648
- Group
- Molluscs
Odostomia acuta
- Peak month
- March
- Records since 2000
- 647
- Group
- Molluscs
Beerbarrel Shell
- Peak month
- July
- Records since 2000
- 633
- Scientific name
- Acteon tornatilis
Peregriana peregra
- Peak month
- September
- Records since 2000
- 632
- Group
- Molluscs
Convex Lantern-shell
- Peak month
- September
- Records since 2000
- 630
- Scientific name
- Thracia convexa
Eastern pearlshell
- Peak month
- July
- Records since 2000
- 629
- Scientific name
- Margaritifera margaritifera
Pointed Cingula
- Peak month
- March
- Records since 2000
- 629
- Scientific name
- Onoba aculeus
Common Spindle
- Peak month
- September
- Records since 2000
- 614
- Scientific name
- Colus gracilis
Coryphella browni
- Peak month
- May
- Records since 2000
- 612
- Group
- Molluscs
Keeled Slug
- Peak month
- September
- Records since 2000
- 606
- Scientific name
- Tandonia sowerbyi
European jingle shell
- Peak month
- August
- Records since 2000
- 599
- Scientific name
- Anomia ephippium
Green Ormer
- Peak month
- September
- Records since 2000
- 599
- Scientific name
- Haliotis tuberculata
Tiger scallop
- Peak month
- August
- Records since 2000
- 594
- Scientific name
- Palliolum tigerinum
Spotted risso
- Peak month
- July
- Records since 2000
- 593
- Scientific name
- Pusillina inconspicua
Ribbed Grass Snail
- Peak month
- May
- Records since 2000
- 586
- Scientific name
- Vallonia costata
Slit Limpet
- Peak month
- August
- Records since 2000
- 585
- Scientific name
- Emarginula fissura
Boston Facelina
- Peak month
- June
- Records since 2000
- 581
- Scientific name
- Facelina bostoniensis
Ghost Slug
- Peak month
- November
- Records since 2000
- 573
- Scientific name
- Selenochlamys ysbryda
Vitreolina philippi
- Peak month
- August
- Records since 2000
- 564
- Group
- Molluscs
Toothless Chrysalis Snail
- Peak month
- May
- Records since 2000
- 561
- Scientific name
- Columella edentula
Crowned Aeolis
- Peak month
- June
- Records since 2000
- 557
- Scientific name
- Facelina auriculata
Fuzzy Onchidoris
- Peak month
- July
- Records since 2000
- 556
- Scientific name
- Onchidoris muricata
Suborbicular Kellyclam
- Peak month
- August
- Records since 2000
- 551
- Scientific name
- Kellia suborbicularis
Duck Mussel
- Peak month
- April
- Records since 2000
- 550
- Scientific name
- Anodonta anatina
Rayed trough-shell
- Peak month
- August
- Records since 2000
- 546
- Scientific name
- Mactra corallina
Canoe-shell
- Peak month
- March
- Records since 2000
- 543
- Scientific name
- Scaphander lignarius
Frond-Aeolis
- Peak month
- June
- Records since 2000
- 539
- Scientific name
- Dendronotus frondosus
Pod Razor
- Peak month
- June
- Records since 2000
- 536
- Scientific name
- Pharus legumen
Barnacle-eating onchidoris
- Peak month
- July
- Records since 2000
- 535
- Scientific name
- Onchidoris bilamellata
Shining Pea Mussel
- Peak month
- September
- Records since 2000
- 533
- Scientific name
- Euglesa nitida
Crimora papillata
- Peak month
- June
- Records since 2000
- 532
- Group
- Molluscs
Prickly Snail
- Peak month
- May
- Records since 2000
- 530
- Scientific name
- Acanthinula aculeata
Red-crusted Pea Mussel
- Peak month
- December
- Records since 2000
- 523
- Scientific name
- Euglesa personata
Moss Chrysalis Snail
- Peak month
- July
- Records since 2000
- 518
- Scientific name
- Pupilla muscorum
China Limpet
- Peak month
- August
- Records since 2000
- 516
- Scientific name
- Patella ulyssiponensis
Bristly mail chiton
- Peak month
- August
- Records since 2000
- 515
- Scientific name
- Acanthochitona crinita
Rough whorl snail
- Peak month
- July
- Records since 2000
- 514
- Scientific name
- Columella aspera
Adriatic Mussel
- Peak month
- August
- Records since 2000
- 512
- Scientific name
- Modiolus adriaticus
Duvaucelia lineata
- Peak month
- June
- Records since 2000
- 502
- Group
- Molluscs
Swan Mussel
- Peak month
- April
- Records since 2000
- 499
- Scientific name
- Anodonta cygnea
Eulima bilineata
- Peak month
- August
- Records since 2000
- 487
- Group
- Molluscs
White Atlantic Cadlina
- Peak month
- May
- Records since 2000
- 483
- Scientific name
- Cadlina laevis