Fish in the Bay – April 2022, Part 2: Supplemental Report – The Bestiary.

Random observations from April trawls in Lower South San Francisco Bay.  These were a series of Facebook posts that didn’t get captured in blog or email.

1. Shovelnose Guitarfish.

This baby Guitarfish is another rare catch for us here in the south part of the Bay. We have netted no more than one per year over the last several years. All but one that we ever caught were small babies like this one. They grow to up to 5.5 feet.

You can tell by the shape, that this fish lives on the sandy or muddy bottom. They like to bury themselves up to their eyeballs. Then they wait to ambush small flatfishes and crabs, and they dig for worms.

An older photo: Dr. Jim Hobbs holding the only adult we ever caught on 22 July 2018.

They say that thousands of adult mama Guitarfish swim into San Francisco Bay and other protected coastal beaches and inlets every spring to early summer to give live birth to up to 28 pups after a gestation period of almost a year.

Aside from the size of each litter, Guitarfishes grow and reproduce rather slowly. These fish become sexually mature at age 7 or 8 and live up to 16 years. As a consequence, many Guitarfish species around the world are critically endangered. Our variety, the Shovelnose, is possibly near threatened. But, so far it is not listed.

Micah examining the baby Guitarfish on 3 Apr 2022.

People fish for them from piers on the coast, and they are often sold as ‘Fish and Chips’ in Santa Barbara.

2. Plainfin Midshipman.

Plainfin Midshipmen are a common fish on the coast, but they are rarely caught this far south in the Bay.  Aside from baby Midshipmen that we occasionally see in winter through early summer, this is only the fifth adult we have netted in several years of trawling: 4 adults in 2021, and now this one.

I have told the Midshipman story many times before, but I always like telling it:  Midshipmen* are the magical purple “Singing Toadfish.” (* The correct plural might be “Midshipmans”)

• Magical fact #1. At up to 2 hours in duration, the mating call hum from the Male-type 1 is the longest vocalization of any creature on planet Earth! People living in houseboats in Sausalito in the 1980s complained to the local electric company that generators were making too much noise at night – true story. There were no generators. The never-ending hum came from alpha male Midshipmen calling their wives to deposit eggs in their sheltered rocky caves.
• Magical Fact #2. Midshipmen come in three sexes: Male-type 1, Male-type 2, and Female. Male-type 1s are the alpha singing males. They guard nests in caves and hum to attract females to lay their eggs. Males of the type 2 variety are smaller and mimic females. Type 2s try to sneak past the big alpha males to fertilize the guarded eggs.
• Magical Fact #3. They glow in the dark! Midshipmen have over 400 bioluminescent photophore dots. The photophores look like strings of tiny shiny pearls across the fish’s back, sides, and belly. This fish literally lights up like a Christmas tree when it wants to. (Actually, Midshipmen predate the Christmas tradition by millions of years. It is more appropriate to say that Christmas trees light up like Plainfin Midshipmen.)

I took as many photos as possible. When I picked him up to take a last picture of his big singing mouth, he wisely decided that he had had enough. He flipped out of my hand and dove back into the Bay.

3. Dungeness Crab.

This young Dungeness was caught and released at station LSB1 on Sunday, April 3rd. Dungeness Crabs are rare where we trawl in Lower South San Francisco Bay. It has been two years since we saw the last one. We only catch them young and small.

• The broad apron on her ventral side indicates she is female. Judging from the ODFW guide, this one is perhaps two years old and at the threshold of sexual maturity. She will need to grow at least another year or two before she is a legal-sized catch. (Please note, adult males are generally larger. It is considered wise fishery management to release females!) https://www.dfw.state.or.us/MRP/shellfish/crab/Lifehistory.asp    
• These crabs live 8 to 13 years, and they are very delicious. Every animal capable of breaking their armor eats them.
• The commercial fishing season for Dungeness Crabs on the coast has been shortened in recent years due to Humpback Whale entanglements. CDFW recently closed the Dungeness fishery again for that reason. https://wildlife.ca.gov/News/cdfw-moves-quickly-to-close-the-commercial-dungeness-crab-fishery-statewide-in-response-to-humpback-whale-entanglements

4. Harbor Seal Pups.

Springtime is seal pupping season here. We passed by the Harbor Seal haul out and rookery at Calaveras Point in Lower South San Francisco Bay on Sunday, April 3rd. We expected to spot at least a few newborn pups of the season. Micah and I both snapped photos using max telephoto from the rocking boat.

Pups are not easy to spot. They tend to be slate gray in color, covered in mud, and often concealed behind a protective mom. But, by comparing shots from different angles, we think we confirmed seven new pups! Plus, we saw other pregnant females that look due to deliver over the next few weeks.

We took dozens of photos and spotted seven pups  …

We kept a safe distance in the middle of the wide mouth of Coyote Creek. We must not alarm moms with new pups.

5. Surf Scoters.

A male Surf Scoter near Coy4 on 3 April 2022.

Like most migrating ducks, Surf Scoters nest in the far north, in freshwater lakes near boreal forests, just south of the Arctic tundra. In winter, they fly south to warm feeding grounds in South San Francisco Bay and other coastal sites in California.

The California coast is also a Sea Duck courtship place. Boy and girl Scoters meet and bond before they return home. If you look closely in group photos, you can see they tend to be paired up, male and female.

Scoters perform a valuable ecological service. When they are not resting, they are eating. They dive for small crabs, larval fish, clams, and other mollusks.

This part of SF Bay is cursed with several non-native mollusk species: Corbula Clam, Atlantic Oyster Drill, and Philine Headshield Sea Slug. Interestingly, we generally see fewer of these nuisance species when Scoters are abundant.

• We regard Scoters as soldiers in the wintertime Great Army of Diving Ducks who control these invasive pests. (Ruddy Ducks, Golden Eyes, Buffleheads, and Scaup – aka “bluebills” are other members.)
• Scoters are very shy birds. Our boat is big and noisy. We only get the most distant and fleeting glances of them. Except for a couple of bold stragglers, most of these Scoters maintain a 1,000-foot buffer between us and them. This makes for difficult photography.
• Surf Scoters are not listed as threatened, but their numbers have declined substantially in recent decades. We need more Scoters here!