17 de octubre de 2020

150th Anniversary of the Lake Merritt Wildlife Refuge

It's the 150th anniversary of the first wildlife refuge in the nation - Lake Merritt in Oakland!
There will be a virtual celebration on Friday, October 23rd 7-8 pm on the Zoom.

Hear live-streamed remarks from marine biologists Jim Carlton and Andrew Cohen,and many other speakers from science, history, conservation and environmental justice. Time permitting, there will be an opportunity to ask questions via chat.

See the full list of speakers on the Eventbrite invitation. Zoom link will be sent via email before the program.

Please register online for a thoughtful, upbeat, fun community education event. FREE.

Anotado en octubre 17, sábado 23:33 por ktnoon ktnoon | 0 comentarios | Deja un comentario

06 de mayo de 2020

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, .

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

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)

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

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


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

Nematoda (in plankton)

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.

Pennate Diatoms- Several kinds
Chain diatoms
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.

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


Anotado en mayo 06, miércoles 04:30 por ktnoon ktnoon | 0 comentarios | Deja un comentario

12 de enero de 2020

Critter Hunt at Lake Merritt with Naturalist Damon Tighe

Great turnout for citizen science activities at Lake Merritt! We've got something going here. Thanks to everyone who identified organisms, collected plankton and helped drive the underwater robotic vehicle, and especially to Damon who shared his natural history and photography expertise.

Here is a preliminary species list for the day. We saw and mostly photographed at least 23 species not including plankton. There were a lot of phytoplankton, mostly Chaetoceros and many zooplankton of the usual types (copepods in different stages, evadne, mollusk larvae, polychaete veligers). Rate-Our-Plankton level = Tiny Threads

CRITTER WALK Water quality:
Water Temperature 12top/
Salinity 30 ppt top/30 ppt bot
pH 7.5 top/7.5 bot
D.O. 9 ppm/7 ppm
Secchi 100 cm, Depth 150 cm

Red-eyed Medusa - Jelly- Polyorchis penicillatus
Sponge Halichondria bowerbankia
Sea anemones

Diadumene spp. double white striped, orange striped
Diadumene franciscana

Red-striped barnacle Amphibalanus amphitrite
Roly-Poly Isopod Sphaeroma quoianum
Oriental shrimp Palaemon macrodactylus

Bay mussel Mytilis galloprovincialis
Soft-shell clam Mya arenaria
Philippine littleneck clam Ruditapes philippinarum (shell only)
Mud snail Tritia obsoleta
Bubble snail Haminoea japonica
Oyster drill Urosalpinx cinerea

Sea squirts
Ciona savignyi
Molgula manhattensis
Botryllus schlosseri
Botrylloides violaceus

Tubeworm Ficopomatus enigmaticus
Scale worm Harmothoe imbricata
Spaghetti worm Terebellid
Spionid Boccardia proboscidea

Branching bryozoan Bugula
White crust Conopeum sp.

Red algae Lomentaria hakodatensis (?) mentioned in Chang et. al poster about Lake Merrittt,
“A Classic Estuarine Lagood of the 1960’s Undergoes Oceanization by the 2010’s: Remarkable Changes in the Biodiversity and Community Composition.” 2017 State of the San Francisco Bay Estuary Conference Abstracts p. 118



To be revised and continued.

Anotado en enero 12, domingo 19:32 por ktnoon ktnoon | 0 comentarios | Deja un comentario

01 de diciembre de 2019

Plankton tow on November 29th, 2019

Anticipating the upcoming week of rainfall, I thought I'd check out the plankton in Lake Merritt before the brackish water goes fresh. The surface water went from a well-mixed salinity 32 parts per thousand (ppt) on Nov. 24th to stratified 22 ppt at the top and 31 ppt at the bottom on November 29th after a brief rain when I took my plankton tow. I photographed plankton with my iPhone through a student microscope at 40 and 100 x magnification. The photos are in the Lake Merritt Species Project. It will be interesting to see what changes happen after the storms.

Taken from west side of longer open floating dock.
Water depth 210 cm, temperature 9 degrees Celsius top/12.5 degrees Celsius bottom, dissolved oxygen 4 ppm/3.5 ppm bottom, salinity 22 ppt top/31 ppt bottom, pH 6.5 top/7 bottom, Secchi 110 cm.

Plankton net used was 50um mesh.
Magnification was either 40X or 100X. Photos by student microscope and iPhone.
Rate-Our-Plankton-Density = CLEAR

PHYTOPLANKTON: https://www.eoas.ubc.ca/research/phytoplankton/index.html
Thalassiosira (although I think I see two central connecting strands not one)
Melosira, several stages of copepod (nauplius and calanoid?).
Chaetoceros - corkscrew -type (according to hand-out from Romberg Tiburon Center event this is a different species from the straight Chaetoceros), Chaetoceros debilis
Something – Skeletonema?

Copepods: copulating copepods with long antennae, 2 kinds of copepods,
Polychaete larvae with big heads with bristles and skimpy bodies, many zooming trochophore larvae
Flatworm-type worm
Possible barnacle larvae distinguished from copepod nauplii by jerky swimming style (helpful hint from Charles Ford),

When viewed plankton sample was 2 hours -2 days old ☹.

Anotado en diciembre 01, domingo 16:42 por ktnoon ktnoon | 0 comentarios | Deja un comentario

03 de noviembre de 2019

Thanks to Amy Bohorquez' Biology class at Laney College for field work on October 24th!

10-24-species list: Sampled from 2 places: Lake Merritt Boating Center dock (Carlton site G) and the amphitheater beach area (Carlton site C). I brought organisms from dock to the class meeting place by amphitheater green pedestrian bridge.

Water quality measurements were taken from the green bridge over the entrance to Lake Merritt Channel: Temperature 20 degC top/22 degC bottom; Salinity 27 ppt top/bottom; Secchi depth >1.25 m; Dissolved oxygen 7 ppm top/8 ppm bottom; pH 7 top/7 bottom; 2:30 p.m.; ebb tide.

Amphibalanus amphitrite C,G
Amphibalanus improvisus C (not sure of that)
Mytilus galloprovincialis C,G
Breadcrumb sponge (Halichondia bowerbanki) G
Diadumene sp. (large, long tentacles, barrel covered by debris). G
Ciona savignyi G
Molgula manhattensis G – hardly any compared to 9-14
Bottrylus schlosseri G
Ficopomatus enigmaticus G
Worm that build big mud tubes.
Tan arborescent bryozoans G
Mya arenaria G
Ruditapes philippinarum shell only C
Haminoea japonica G
Urosalpinx cinerea G
Caprellid - Skeleton shrimp G
Sphaeroma quoianum C, G
Sea lettuce Ulva
Cladophora (?)
Red algae

Anotado en noviembre 03, domingo 16:19 por ktnoon ktnoon | 0 comentarios | Deja un comentario

13 de octubre de 2019

Final Species List and Discussion for Andrew Cohen's September 14th and October 5th "Critter Walk."

Again many thanks to Dr. Cohen!

Critter list for Lake Merritt walks on 9/14/2019 and 10/5/2019
Duck Ponds to Boathouse Docks

  • indicates that the species is in www.exoticsguide.org.
    (N) indicates a native species and (I) an introduced non-native species.

Sponges (Porifera)
Halichondra bowerbanki (yellow sponge, crust-of-bread sponge) (I) on dock sides (9/14 & 10/5)

Anemones (Anthozoa)
Diadumene lineata* (I) on rocks & dock sides (originally named Sagartia luciae); green column, sometimes with vertical orange lines on column, yellowish tentacles (9/14 & 10/5)
Diadumene leucolena (I) with vertical double white lines on column; on dock sides & rope (9/14)
(The anemone I said was a Metridium on 9/14 might have been D. leucolena.)

Sea worms (Polychaeta)
Ficopomatus enigmatica* (I) (tube worms on dock sides and on rocks below upper zone of barnacles) (9/14 & 10/5)
Terebellid worm (Spaghetti worm) in clay tube, collected at docks (10/5)

Snails & Sea Slugs (Gastropoda)
Tritia obsoleta* Atlantic Mudsnail (I) on mud and rocks (9/14 & 10/5; egg cases on 9/14 only)ly)
Urosalpinx cinerea* Atlantic Oyster Drill (I) snails with yellow or orange, ocassionally white, shells, on rocks and dock sides (9/14 & 10/5; vase-shaped egg cases found under rocks on 10/5)
Assiminea californica (N) tiny brown snail on underside of rocks (9/14) (there are pictures of Assiminea on the Myosotella myosotis page at www.exoticsgide.org)
Haminoea japonica (I) slugs, kidney-shaped gelatinous egg masses with yellow eggs, and a few delicate, transparent internal shells found on rocks, dock sides, undersides of rocks (9/14 & 10/5; egg masses abundant and slugs fairly common on seaweed on 10/5)

Clams & Mussels (Bivalvia)
Geukensia demissa* Atlantic Ribbed Horsemussel (I) shells on mud, live mussels on rocks and undersides of rocks (9/14 & 10/5)
Mytilus trossulus (N), Mytilus galloprovincialis (I), or hybrids Bay Mussel or Blue Mussel - on rocks, dock sides, ropes, undersides of rocks (9/14 & 10/5)
Arcuatula senhousia* Green Bagmussel or Asian Date Mussel (I) on rocks, dock sides, underside of rocks (9/14; empty shells and parts of shells found among Mytilus byssal threads on 10/5)
Mya arenaria* Eastern Softshell Clam (I) shells common on mud (9/14 & 10/5; small live clams found among Mytilus byssal threads on 10/5). (Cryptomya californica, a native species in the same family that also has a chondrophore—a shelf-like structure that forms the hinge on the left valve—discussed in connection with its shallow pallial sinus and association with burrows of other animals).
Ruditapes philippinarum* Japanese Littleneck Clam, Manila Clam (I) someone brought me one empty shell near the end of the walk on 9/14
Probably in the genus Nebalia or an allied genus - Katie Noonan found one near the docks. (9/14)

Barnacles (Cirripedia)
Amphibalanus amphitrite* (I) on rocks (9/14 & 10/5)

Rolly-pollies, sowbugs (Isopoda)
Sphaeroma quoianum (I) the larger isopod, among barnacles and in empty barnacle shells on the sides of large rocks (on 10/5) and on undersides of smaller rocks (9/14 & 10/5); usually with a double row of 4 bumps on its tail segment; this spices sticks out the small limbs alongside its tail segment ("uropods") when it rolls up into a ball
Gnorimosphaeroma oregonense (N) the smaller isopod, on the undersides of rocks; often with a broad, gray stripe along its back; does not stick out the small limbs alongside its tail segment when it rolls up into a ball (9/14 & 10/5)
(Discussed: Iais californica (I) commensal on the underside of Sphaeroma quoianum)

Scuds, Sand Fleas (Amphipoda)
Unidentified amphipod in the suborder Gammaridea - underside of a rock (9/14)
Skeleton shrimp - on dock sides; these are highly modified amphipods in the family Caprellidae (9/14 & 10/5)

Crabs & Shrimp (Decapoda)
Pagarus sp. Hermit Crab (N) in an Oyster Drill shell, on rocks (9/14)
Palaemon macrodactylus (I) one found among dock fouling; Asian shrimp thought to be from Korea based on its discovery in the Bay around the time of the Korean War (10/5)

Conopeum tenuissum? - small colonies of an encrusting, membraniporine bryozoan that may be this species, on organisms attached to dock sides (9/14 & 10/5)
unidentified arborescent (branching, bushy) cheilostome bryozoan - small colonies on dock sides (9/14 & 10/5)

Sea Squirts (Tunicata)
Molgula manhattensis (I) very abundant on the dock sides (9/14 & 10/5)
Ciona savignyi (I) I saw one that was dound on the side of the docks (10/5)

Tridentiger sp. Goby (I) on mud (10/5)

Marsh Plants (I've listed the typical zonation pattern, but this may be less apparent in the small bits of recently-created brackish marsh at Lake Merritt)
Baccharis pilularis Coyote Bush (N) - high marsh/dry land transition (9/14 & 10/5)
Grindelia stricta Gumplant (N) - high marsh and slough levees (9/14 & 10/5)
Distichlis spicata Salt Grass (N) - high marsh (9/14 & 10/5)
Limonium Marsh Rosemary or Sea Lavendar (N) - high marsh (9/14)
Salsola soda Mediterranean Saltwort (I) - high marsh (9/14 & 10/5)
Jaumea carnosa (N) - marsh plain (9/14 & 10/5)
Sarcocornia pacifica (formerly Salicornia virginica) Pickleweed (N) - marsh plain (9/14 & 10/5)
Frankenia salina Alkali Heath (N) - marsh plain (9/14 & 10/5)

Birds of Note
Canada Geese and Mallard Ducks (9/14 & 10/5) On 10/5 discussed the biological, morphological, genetic and ecological species concepts; on 9/14 & 10/5 discussed Dave Wilcove's concept of Canadoids and Mallardoids, and Dave Covel's introduction of Canada Geese to Lake Merritt.
Double-crested Cormorants (9/14 & 10/5) On 9/14 we had the lovely experience of watching a comorant swim around underwater in front of us searching for a snack as gobies scattered before him; and discussed observations in the 1940's of regular "team fishing" by enormous flocks of comorants in San Francisco Bay between Berkeley and Emeryville.
Great Egret (9/14 & 10/5)
White Pelicans (9/14)
Coot (10/5)

Some Other Discussions
California Ridgway's Rail (former name: California Clapper Rail, which I still tend to use) interactions with the Atlantic Ribbed Horsemussel. (9/14 & 10/5)
The interactions of Saltmarsh Song Sparrows and Marsh Wrens in non-native cordgrass marsh. (9/14)
Clam shell anatomy; the size of the pallial sinus as an indicator of a clam's ecology (depth in the mud and types of predators); and why the native clam Cryptomya californica is typically found at depth despite its small pallial sinus. (9/14 & 10/5)
The recent and ongoing extirpation of the native mudshrimp by a non-native bobyrid isopod parasite; and how the arrival of a non-native mudshrimp may eliminate any density-dependent restriction of the parasite's impact on the native mudshrimp population. (10/5)
My hypothesis that marine avian schistosome populations are sustainable only at sites where both the snail host and the primary avian host are present in great abundance, and may be spread to temporary, secondary sites by the bird hosts. In the case of San Francisco Bay's two swimmer's itch outbreaks at Crown Beach in Alameda, the main populations may have been at the Lake Merritt bird sanctuary, where both water birds and snail hosts are abundant, and exported by commuting birds to create a secondary population at the beach where people regularly wade in the water and are exposed to the cercaria. (10/5)

Anotado en octubre 13, domingo 19:57 por ktnoon ktnoon | 0 comentarios | Deja un comentario

14 de julio de 2017

Welcome! Organizing and Big Questions

Welcome to the Lake Merritt Citizen Monitoring Study! The purpose of this project is to continue the 50+ year study of the aquatic community at Lake Merritt started by Dr. Jim Carlton of Williams College (from 1962 to 1972) and re-launched by the Smithsonian Institution (since 2016). Jim Carlton made an exhaustive survey of Lake organisms while he was an Oakland High School student starting as a freshman in 1962, and continuing into his undergraduate years at UC Berkeley. You can see him as a high school student near Site G on the project map. By 1972 he had found approximately 50 invertebrate species living in the lake — only 11 of which were natives. In October 2016, Carlton and Dr. Andrew Chang and colleagues from the Smithsonian Environmental Research Laboratory (SERC) branch in Tiburon repeated Jim’s 1960s survey using the same field sites (A-H) and methods as much as possible. They found approximately 50 invertebrate species in a single day, which included many fully marine species not found in the Lake in the 1960s.
[This appears to have been due to Lake Merritt having become much more salty over the years.]

Then came the rainy winter of 2017!
This is a unique opportunity to see how a professionally-censused estuary lagoon community responds to drought, extreme freshening events, bioinvasions and climate change.
How many species will survive? Will new species appear? How will they appear in the community (zonation, numbers)?
Water temperature and salinity are important environmental variables and different species have different tolerances and adaptations to variations. If you can measure salinity with an aquarium hydrometer and temperature when you make observations, that's great. But if you can't don't let that stop you. I will try to add that data as a comment if it was recorded by other observers. If you would like to get an official LMCMS checksheet and picture guide, please send me an iNaturalist message!
I will try to add photos taken this spring and photos I have taken going back to the early 2000's.

Anotado en julio 14, viernes 15:39 por ktnoon ktnoon | 0 comentarios | Deja un comentario