Recent Observations on Predation

Observation No. 1 – Didemnum vexillum being preyed upon by a chiton, a sea urchin, and a sea star in Shakespeare Bay, South Island, New Zealand. December, 2003.

Source

A. Coutts (CI). Photo date and credit: December, 2003; A. Coutts

Image AC_SB_NZ007

Image AC_SB_NZ007. The chiton Cryptoconchus porosus grazing on Didemnum vexillum on rocks underneath Waimahara wharf, Shakespeare Bay. Water depth 3 m. Water temperature approximately 17 deg C. December 2003. Photo credit: Ashley Coutts, Cawthron Institute. Location no. 11 Click here to download image.

Image AC_SB_NZ008

Image AC_SB_NZ008. The pink sea urchin Notechinus albocinctus grazing on Didemnum vexillum on the seabed underneath Waimahara wharf, Shakespeare Bay. Water depth 3 m. Water temperature approximately 17 deg C. December 2003. Photo credit: Ashley Coutts, Cawthron Institute. Location no. 11 Click here to download image.

Image AC_SB_NZ009

Image AC_SB_NZ009. The common cushion starfish Patiriella regularis grazing on Didemnum vexillum on the seabed underneath Waimahara wharf, Shakespeare Bay. Water depth 3 m. Water temperature approximately 17 deg C. December 2003. Photo credit: Ashley Coutts, Cawthron Institute. Location no. 11 Click here to download image.

Observation No. 2 – Didemnum sp. being preyed upon by the common periwinkle, Littorina littorea, in the Sandwich tide pool, Sandwich, MA. February 3, 2004.

This is the first documented observation of the common periwinkle, Littorina littorea (an invasive species), preying upon Didemnum sp. in New England. This observation was made in winter when the didemnid colonies were weak and/or dying, and it is not known if this form of predation occurs during other seasons of the year when the colonies are growing actively.

Source

Page Valentine (USGS) and Mary Carman (WHOI). Photo date and credit: February 3, 2004; Dann Blackwood (USGS).

Image DB_STP_DSC0090

Image DB_STP_DSC0090. View of the Sandwich tide pool on the south side of the east entrance of the Cape Cod canal at low tide, looking east (41 deg 46.42 min N lat, 70 deg 29.30 min W lon). Water depth, intertidal, 11 foot (3.4 m) range. Water temperature 1 deg C. Observed at low tide. February 3, 2004. Photo credit: Dann Blackwood (USGS). Location no. 1. Click here to download image.

Image DB_STP_DSCN2010

Image DB_STP_DSCN2010. Tunicate colonies of Didemnum sp. encrusting a boulder and being preyed upon by the common periwinkle, Littorina littorea. Note that the snails are numbered for comparison with the following images. Elliptical and subcircular holes in D. sp. are interpreted to represent areas that have been grazed by the periwinkles. Sandwich tide pool (41 deg 46.42 min N lat, 70 deg 29.30 min W lon). Water depth, intertidal range to 11 feet (3.4 m). Water temperature 1 deg C. Observed at low tide. February 3, 2004. Observers: Page Valentine (USGS) and Mary Carman (WHOI). Photo credit: Dann Blackwood (USGS). Location no. 1. Click here to download image.

Image DB_STP_DSCN2011

Image DB_STP_DSCN2011. Tunicate colonies of Didemnum sp. encrusting a boulder and being preyed upon by the common periwinkle, Littorina littorea. Snail no. 1 has been removed to show area grazed through the D. sp. colony. Elliptical and subcircular holes in D. sp. are interpreted to represent areas that have been grazed by the periwinkles. Sandwich tide pool (41 deg 46.42 min N lat, 70 deg 29.30 min W lon). Water depth, intertidal range to 11 feet (3.4 m). Water temperature 1 deg C. Observed at low tide. February 3, 2004. Observers: Page Valentine (USGS) and Mary Carman (WHOI). Photo credit: Dann Blackwood (USGS). Location no. 1. Click here to download image.

Image DB_STP_DSCN2012

Image DB_STP_DSCN2012. Tunicate colonies of Didemnum sp. encrusting a boulder and being preyed upon by the common periwinkle, Littorina littorea. Snails no. 1, 2 and 3 have been removed to show areas grazed through the D. sp. colony. Elliptical and subcircular holes in D. sp. are interpreted to represent areas that have been grazed by the periwinkles. Sandwich tide pool (41 deg 46.42 min N lat, 70 deg 29.30 min W lon). Water depth, intertidal range to 11 feet (3.4 m). Water temperature 1 deg C. Observed at low tide. February 3, 2004. Observers: Page Valentine (USGS) and Mary Carman (WHOI). Photo credit: Dann Blackwood (USGS). Location no. 1. Click here to download image.

Image DB_STP_DSCN2015

Image DB_STP_DSCN2015. Tunicate colonies of Didemnum sp. encrusting a boulder and being preyed upon by the common periwinkle, Littorina littorea. Snails no. 1-6 have been removed to show grazed areas in the D. sp. colony. Snails 1-3 have grazed through the tunicate, snail no. 4 has grazed the surface of the colony, and snails 5 and 6 were grazing the edges of a large hole in the colony when they were removed. Elliptical and subcircular holes in D. sp. are interpreted to represent areas that have been grazed by the periwinkles. Sandwich tide pool (41 deg 46.42 min N lat, 70 deg 29.30 min W lon). Water depth, intertidal range to 11 feet (3.4 m). Water temperature 1 deg C. Observed at low tide. February 3, 2004. Observers: Page Valentine (USGS) and Mary Carman (WHOI). Photo credit: Dann Blackwood (USGS). Location no. 1. Click here to download image.