Fish in the Bay – July 2022, Palaemon Shrimp take over.

Record-breaking Palaemon Shrimp month: almost 13,000 were caught in July.  The previous record monthly catch was in November 2021 when 8,335 were netted.  So far, 2021 still stands as our record Palaemon year, but it is very likely that the annual record will also be broken in just a few more months.

• Unfortunately, native Crangon shrimp have again declined as the season warmed. Only 441 were caught this month.  The lack of cool season rain probably hampered Crangon recruitment. 

Tub full of 2085 Palaemon shrimp at station Coy2 on 9 Jul 2022.  – photo by Luca.

Palaemon Traffic Jam.  The highest numbers of Palaemon by far were at stations Coy1 (6,030) and Coy2 (2,085).  Summertime shrimp numbers are typically high in that part of Coyote Creek, but this was an unusually lopsided distribution. 

Our record Anchovy and Goby year continues, albeit both Goby and Anchovy numbers declined a bit in July.

• The July combined Goby total was 2,079. In any year prior to 2021, that would be the record goby month. But, for 2022 the record was set in May (Baby Fish Month) at almost 4,000 gobies of all types. The number dropped to just over 3,000 gobies in June. 
• For both Gobies and Anchovies, the seasonal trend is similar: high numbers near the initial spawning season in late spring/early summer, then a progressive decline in numbers as the season warms.

Interesting to note: both shrimps and sharks tend to avoid the restored ponds. For sharks this makes sense; shallow ponds are warm and tend to experience swings of low dissolved oxygen.  I don’t know why shrimp would avoid the ponds. 

1. Fishes.

Yellowfin Gobies at Art2

Yellowfin Gobies.  As usual, Yellowfins comprised the bulk of the July gobies: 1,582.   This is a slight and expected drop from the May and June “Baby Fish Month” totals.  According to literature, the young begin migrating upstream as they mature.  And, they are readily eaten by Bat Rats, Herons, and Egrets.

Cymothoid Isopod (Devil Bug).  These gill parasites are more common in late fall and early winter when Shad, Herring, and Longfin Smelt return to Coyote Creek.  In theory, Anchovies should also be suitable hosts, but I don’t recall ever seeing a Devil Bug in an Anchovy gill.

Gobies also appear to be unsuitable hosts. The Bugs are fast and agile swimmers and are always eager to find a new host when they are exposed out in the open.  But, for some reason, Devil Bugs never seem to plant themselves in a goby. 

Gravid Devil Bug.  Cymothoid Isopods hatch as males, They turn into females later in life.  Many types of isopods and crustaceans have strange life histories like this.   This big female was full of eggs.

Longjaw Mudsuckers.  10 Mudsuckers were netted in July.  The year-to-date total is 30 which is decent, but 2022 is not on track to break any Mudsucker records. 

Shimofuri Gobies at Alv1.  Photo by Luca.

Shimofuri Gobies.  We caught 111 non-native Shimos in July.  There was a huge Shimo population explosion, mostly in Alviso Slough, about this time last year, and then a decline.  The numbers have bounced around since then and suggest that a large population of Shimos resides somewhere upstream of station Alv1: either in Guadalupe River or in the Pond A8 complex.

• Shimos appear to have displaced Shokehazi Gobies over the past two years.

Anchovies at Art1. 

Anchovy numbers dropped from 2,633 in June to 1,564 in July. This is still a high number for a July, and Anchovies with eggs or milt were detected at all stations.  The Anchovy spawn of 2022 continues!

Two shiners in pond A21.

Shiner Surfperch.  These are two of four Shiners seen in July.  The darker patch on the dorsal fin of the fish on the left may mark him as either male or more mature.

California Halibut.  16 young Halibut were caught.  All but three of them were at station LSB2. 

 2. Evil Mollusks.

Corbula clam catches were in the single digits for many of the last several months.  Then, 19 were caught in May, 40 in June, now 102 in July!  It was a nice reprieve, but we always expected that these ecosystem killing clams would eventually come back. This is a bad clam! 

Philine snails.  We picked up 33 Philine in June and another 22 in July after several months of seeing practically none.  Philine, aka Tortellini snails, aka Snotball snails, are also known as Headshield slugs and/or New Zealand Sea Slugs.  These opisthobranch gastropods have a rudimentary shell buried deep inside the fleshy slug-like mantle.  (https://en.wikipedia.org/wiki/Philine).  In addition to being non-native and voracious predators of benthic organisms, they are unpleasant to look at and appear to serve no beneficial purpose.

3. Some Birds from Luca.

An American Avocet probes for tiny bugs near Art1.  Photo by Luca

Great Blue Heron stands in a patch of pickleweed and Dodder in Pond A21.  Photo by Luca.

Dodder.  The bright orange mass of hair-like material is the parasitic plant called Dodder.  I have also heard it called “Witches’ Hair” and the ‘Plant from Hell’.  Dodder has no chlorophyll.  Here, it draws all water and nutrient from its pickleweed host.  https://www.britannica.com/plant/dodder 

Although Dodder is a nuisance, it is very colorful, and as far as we know, it is native. It is “Marsh Mistletoe.”

Long-billed Curlew family in Pond A21.  Photo by Luca

Long-billed Curlew.  Curlews are the largest of the sandpipers.  They are easily identifiable by their long curving bills.  Curlew populations were devastated across North America, and practically wiped out in San Francisco Bay, by the early 1900s as a result of hunting and habitat destruction.  They have recovered substantially.  They were delisted by the IUCN from “Near Threatened” to “Least Concern” status in 2008. 

Fun fact:  Curlews are also known as “Candlestick Birds.”  San Francisco’s Candlestick Point and the stadium were named after them. 

• Curlew article by Patricia Gannon: https://alamedasun.com/news/long-billed-curlew-alameda%E2%80%99s-candlestick-bird 
• Wikipedia Curlew page: https://en.wikipedia.org/wiki/Long-billed_curlew 

4. Good signs!

Green Phytoplankton Soup at Art1

Green Water.  Phytoplankton soup is thick in slow-moving upstream sloughs.  It’s the secret sauce for spawning fishes and brooding shrimps. 

Baby Bat Ray at Coy 3.

Bat Ray.  40 Bat Rays were caught this month. That is a high total for a month but not quite a record. All but a few were newborn babies. 

Big fish at Coy1. 

Big Fish.  Sonar detected a big fish on our starboard side as we cruised down the main stem of Coyote Creek on Sunday.  Speckles of small fishes and/or shrimp also showed up in the scan.  Considering the warm water temperature, the big fish was most likely a Leopard Shark.  She may have been a big pregnant mama looking for a place to birth her brood.  

Four baby sharks and shark food (shrimp) at Coy1.

Leopard Shark.  20 Leopard sharks and 2 Brown Smoothhounds were caught in July.  2022 is already our biggest baby shark year ever, and we still have 5 more months to go!

“Evil mollusks” reminded me of the old ELO song “Evil Woman” for no particular reason.  Now I can’t get the tune out of my head.  Enjoy! https://www.youtube.com/watch?v=LBtuk4JcYTs