City Nature Challenge - Lake Merritt BioBlitz 2020

The City Nature Challenge was a great occasion to resurvey the aquatic life at the Lake Merritt Boating Center dock. Thank you to the California Academy of Sciences Citizen Science Department and to the observers and identifiers who contributed to the Lake Merritt BioBlitz 2020. Thirty aquatic species were observed at Lake Merritt this year, in comparison to seventeen last year.

Here is a species list and some observations about differences between this year and last.

Physical conditions: Observed on Fri 4/24, 2020 at Lake Merritt Boating Center Docks
Cool and windy, water temperature 20 degC , salinity 30 ppt; dissolved oxygen 8 ppm, pH 7.5, Secchi 170 cm. Tide gate was probably closed, low tide levels. Lake Merritt received only 1.67 inches of rainfall Jan-Apr 2020, compared to 13 inches in Jan-Apr 2019. Last year, water temperature was 23 degC and salinity was only 22 ppt, .

2020 LAKE MERRITT BIOBLITZ SPECIES LIST
Sponges
Halichondria bowerbanki - Deadman’s finger sponge
Clathria prolifera (by tide-gate) Red-Beard sponge

Sea Anemones
Diadumene lineata - Green-striped anemone
Diadumene franciscana San Francisco anemone

Mollusks
Bivalves
Teredo navalis – Ship’s worm (observed 4/22/2020) or possibly Bankia
Mytilis galloprovinciali*s Mediterranean mussel - Photos taken, smooth not ribbed, all sizes
Mya arenaria – Soft-shelled clam
Ruditapes philippinarum - Japanese Littleneck clam (shell only)

Gastropods
Haloa japonica– Japanese Bubbleshell, many egg masses
Urosalpinx cinerea- Eastern Oyster Drill - several adults and egg cases
Tritia obsoleta- Atlantic Mud Snail

Crustaceans
Palaemon macrodactylus – Oriental shrimp (observed 4/20/20)
Corophiums
Other amphipods
Gnorimosphaeroma oregonense, Sphaeroma quoiannum, needs i.d. - Oregon pillbug
Amphibalanus improvisus – Bay barnacle - many small barnacles encrusting mussels on dock

Worms:

Polychaetes:
Australian tubeworm - Ficopomatus enigmaticus
Pile worm - Nereidae
Fifteen-scaled worm- Harmothoe imbricata
Unidentified polychaete and polychaete larvae.
Syllidae (in plankton)

Nematoda (in plankton)

Tunicates:
Ciona savignyi – Solitary sea squirt
Botryllus schlosseri - Star tunicate
Botrylloides diagenesis - San Diego tunicate
Styela clava – Club tunicate
Acidia zara (?)
But no Molgula manhattensis - unless the misshapen ones with heavy skin flagging are aging M.m.

Plankton:
Coscinodiscus
Pennate Diatoms- Several kinds
Chain diatoms
Tintinnids
Polychaete larvae
Copepods in various stages mostly immatures
Gastropod larvae
D-shaped bivalve larvae.

Sea Weeds: Cladophora (this is possibly incorrect), red algae that needs to be identified (uploaded to iNat as Sarcodithia or Gracillaria). Observed (4/20-4/22) - Enteromorpha, Ulva sheets, Codium fragile floating.

Fish
Gobies, Northern Anchovies, mosquito fish, topsmelt silversides, Northern Pipefish

Not observed last year in BioBlitz: Red Beard Sponge, Styela clava, Diadumene franciscana, Star tunicate, San Diego tunicate, Bay barnacle, Japanese Littleneck clam,

Not observed this year: Okenia plana, rainwater killifish, red-striped barnacle, Asian date mussel, Conopeum, other bryozoans

https://www.inaturalist.org/projects/lake-merritt-2020-city-nature-challenge
https://www.inaturalist.org/projects/lake-merritt-bioblitz-april-2019-city-nature-challenge

Publicado por ktnoon ktnoon, 06 de maio de 2020, 04:30 MANHÃ

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