Fish in the Bay – Merry Fishmas, 2024!

Merry Fishmas everyone!  I fell horribly behind in my fish reporting, so I am combining Fishmas with the November blog. 

November notes:

• Temperatures were several degrees cooler compared to October and the first atmospheric river rolled through in late October. Summer officially ended! 
• Longfin Smelt returned for spawning! 15 young-of-year and more mature year 1s and year 2s  showed up in October.  – I will describe the Longfin catch in the following December blog.
• Sonar continues to image foraging Sturgeon! As temperatures cool, more hungry Sturgeon should arrive to feed in biologically-productive brackish marshes. 

Once again, non-native Silversides were caught in Artesian Slough.

Good news!  The Silverside count dropped considerably from 4,914 in October –  to 1,522 in November – to only 1 (one) in December.  This is typical Silverside behavior: the population explodes during warm months and then disappears when it gets cold.  Unfortunately, Silversides will return!

Other factors to consider: Our otter trawl results only catch Silversides that stray into the main channel.  Silversides prefer to hide in marsh plants along the edges of sloughs. 

• Beach seine surveys over the summer of 2024 caught larger numbers of Silversides in some of the breached salt ponds adjacent to Alviso Slough.
• Warm season Silversides are remorseless eating machines of eggs and larvae of native fishes we like. We should consider controlled management of these non-native demons!

Four of the many non-native Silversides caught at Art2 on 3 November 2024.

Happier news:

2024 was our third best Longfin year: 1,458 … However, this was still about 1,000 Longfins short of our best years in 2022 and 2023.

1. Sharks & Rays – November and December.

Leopard Shark count = 1 in November.  As Sami lifted our November Leopard Shark for release after measurement (790 mm), he noticed something troubling.  This girl shark had at least 8 or 9 blood-sucking copepod parasites stuck to the base and trailing edge of her dorsal fin. This is disgusting and unacceptable!  These parasites cause visible damage to a shark over time.

Copepod parasites can be easily removed with fingertips and gentle pressure.  Speed is essential since Sharks can’t hold their breaths for long out of water.

• Benz et al (2003) Five Species of Parasitic Copepods (Siphonostomatoida: Pandaridae) from the Body Surface of a White Shark Captured in Morro Bay, California  https://www.researchgate.net/publication/29737809_Five_Species_of_Parasitic_Copepods_Siphonostomatoida_Pandaridae_from_the_Body_Surface_of_a_White_Shark_Captured_in_Morro_Bay_California

“Five pandarid (Copepoda) species, Dinemoura produeta, D. latifolia, Echthrogaleus coleoptratus, Pandarus bicolor, and Aehtheinus oblongus, were collected from the external body surface of a white shark, Careharodon carcharias, taken from Morro Bay in the northeastern Pacific Ocean off central California”  (Emphasis added.)

Sami holding the November Shark after parasite removal.

Clean shark, ready for release:  Quick as a wink, Sami’s shark was clean!  Always remove shark parasites if time allows, because … Both you and the shark will be better off for the experience.

Brian Alper shows off our December Shark.

Leopard Shark count in December = 1.  We didn’t find any parasites on this smaller shark the following month. 

Bat Ray count in November = 4.  These four additional baby Rays brought the YTD count to 181. 2024 is now our second-best Bat Ray year since 2010.  (2023 was the record year with 206 Rays.)

Sami Araya with the big mama Ray.

Add two more Rays in December.  We finished the year with another two rays: a big mama Ray and one more baby girl Ray. 

Final Bat Ray count for 2024 = 183. 

2. Clupeiforms

American Shad counts = 2 in November / 62 in December. The total for 2024 was 342.

Threadfin Shad counts = 2 in November / 12 in December. The total for 2024 was 98.

American and Threadfin Shad are cool water / winter fishes.  We saw a few of each in November.  Many more showed up in December.

American Shad and Anchovies in Pond A19.  As expected, the Shad displayed a greener “Jadite” color on its dorsal side where salinity was just above 17 ppt. 

• At the same salinity, most Anchovies were deeper blue. (Note: Anchovy colors were highly variable. A few were much browner – Anchovies are always the trickiest of the Clupeiforms!

Within a few minutes, the blue Anchovies at station A19-4 “browned-down” to a greener hue of “Thermal Spring” as we watched. 

• I can only guess that deep blue Anchovies at this station must have swum in from higher salinity somewhere nearby immediately before capture. Investigation continues.   

Baby Anchovies!  A few dozen baby Anchovies were observed in LSB catches in November – amongst all the other interesting creatures. 

Musculista count = 3 in November / 2 in December.  2024 total = 1,425. 

• In 2023, Musculista mussels (aka “Asian Date Mussels”) seemed to be taking over Lower South SF Bay. A record 4,106 were collected from our typical monthly otter trawls that year. Then, the Musculista count dropped substantially this year.   
• Where did they go? Will they return?  More data is needed!\

Philine count = 3 in November / 2 in December.  2024 total = 78.

• Philine snails peaked in 2022 when 498 were caught by the end of the year. We only caught 59 the following year, and now 78.  They are non-native predators of other mollusks, so a lower count is better … but, where did they go?  … and, why?   
• Is this yet another Fishmas miracle?

3. Halibut & duck hunter. 

California Halibut count = 15 in November / 41 in December.  2024 total = 383.

• 2024 finishes as our best Halibut year after post-El Nino years of 2015/2016. This is a popular and important native game fish. High Halibut counts are a very good thing!
• Some Halibut have vivid blue eyes. Some Halibut have brown eyes.  We began taking note of this phenomenon last summer.  We can now confirm that “blue eye versus brown eye” appears to be a random characteristic.  There seems to be no spatial pattern, and both left-eyed and right-eyed Halibut express either blue or brown eyes at similar frequency.   
• Halibut eye color must mean something! More investigation needed.

Duck hunting season arrived.  A hunter and dog wait for ducks in restored marsh in Pond A19 just before noon on 3 November 2024.

Merry Fishmas & Happy Holidays!  https://www.youtube.com/watch?v=Gw0jE39-i9Q