Field Notes

Journal of marine observations under the Morro Bay T-Pier

Fall, 2017. Ken and I did 3 dives in early October of 2017. The visability was average to about 10-15 feet and the water cold, about 54 degrees. The colder water may have explained the remarkable return of the nudibranch Hermissenda opalescens (formerly Hermissenda crassicornis). The Hermissendas were back by the thousands, although most were quite small. We also photographed a few Janolus barbarensis, one-spot bennies and an octopus. Still missing from the pier pilings are the usual thick gardens of metridium anemones.

Fall, 2016. Ken and Gary did three dives in Morro Bay under the North T-Pier. The water was full of sedimentwith average to poor visibility. Water temperature was colder, 55 to 57 degrees than our last dives in the Fall of 2015. We spotted 7 species of nudibranchs including the first time seen Flabellina iodinea (Spanish Shawl). We saw several individuals of the species Triopha catalinae. We also saw several Navanax inermis nudibranchs including one laying an egg skein. This beautiful animal often feeds on other nudibranchs. Still misssing was the nudibranch Hermissenda crassicornis and strangely, metridium anemones which at one time covered the pilings at the shallow end of the pier. Other species were normal including lots of fish life circling the pilings.

Fall, 2015. Ken and Gary did three (Ken four) days of diving under the North T-Pier in terrific dive conditions. Water visibility was excellent and the topside weather was sunny and warm. However, the water temperature was an astounding 61 to 63 degrees! Over the last 25 years of diving under the pier, water temperature would vary from 48 to 55 degrees. This spring, we noted an increase of about 7 degrees. Warmer water is certainly changing marine life under the pier. Gone are most species of nudibranchs including the once abundant Hermissenda crassicornis. Red bryozoan, once found on most pier pilings, is now completely absent. New marine life, including the bay fringehead blenny, are now appearing. Also, sea stars, having weathered a recent plague, are increasing in abundance.

Spring, 2015. Ken and I did three days of diving under the Morro Bay North T-Pier. Conditions were almost perfect with excellent underwater visability. However, as we had observed in 2014, the nudibranch population was almost nil. We saw a few small Janolus barbarensis and Trapania velox and one Hermissenda crassicornis which normally number in the thousands. Water temperature in both late 2014 and on our dive this year is considerably warmer perhaps by as much as an average of 7 degrees. We think this plays a part in the disappearance on nudibranch life under the pier. Other marine organisms, anemones, crabs, fish, octopus, clams, and barnacles are as abundant as ever. Topside while dining at the Harbor Hut, we sighted a juvenile grey whale entering the bay. We assume he exited later on the out tide.

Spring, 2014. Ken & I did three dives under the Morro Bay North T-Pier and were astounded about the lack of nudibranch life under the pier. The beautiful nudibranch, Hermissenda crassicornis, was almost totally absent. This is the species that we would normally see in the hundreds or perhaps thousands if we counted closely.
After more than 20 years of diving the T-Pier, this was the first time we have encountered such a paucity of nudibranch life. Also completely missing from the pilings and seabed were the invasive red bryozoan. Other species, such as anemones, blennies, barnacles and crabs were present and in normal abundance. We asked Lisa Needles, marine biologist with Cal Poly, if she had any ideas concerning this radical change. She mentioned two possibilities: heavy storm surge that recently swept the Central Coast and a change in salinity due to heavy runoff into the bay. Lisa will be doing a follow up dive to see if life under the pier returns to normal.

Summer, 2012. Once more we were treated to a population boom of the strikingly beautiful nudibranch, Janolus barbarensis. We had seen a similar population explosion in October, 2011. The nudibranchs were large and most often seen on kelp. Another nudibranch, which is often seen but in small numbers, called Polycera atra, had a tremendous increase in numbers as well. We saw these nudibranchs in large groups, sometimes up to a dozen individuals on their prey bryozoan.

Winter, 2011. During our dives under the North T-Pier in November & December we found and photographed three new (to us) species of nudibranchs. The first, Onchidoris bilamellata, was observed in congregations with individuals almost layered on one another. Nearby, the nudibranch's eggs masses were affixed to every possible substrate. These nudibranchs seemingly appeared from nowhere to be found in large numbers, particularly at the outside edge of the pier. In our December dives, with exceptionally clear water and 30 foot plus visibility, we found and photographed the nudibranch species Aglaja ocelligera and Pleurobranchaea californica. Thanks to Gary McDonald for his help in identifying the nudibranchs. All three new species can be seem on the 'nudibranchs' page of this website.

Fall, 2011. In October, 2011, Ken and I dove both the South and North T-Piers. On both dives we were astounded and delighted to find the greatest numbers of the spectacularly beautiful nudibranch, Janolus barbarensis, we have even seen. If we had seen two or three specimens of this nudibranch a year, we thought ourselves lucky. Ken and I each photographed about a dozen Janolus on each dive. They seemed to be everywhere: on pilings, sand, bryozoans, I even photographed one on the claw of a large crab. This is another example of the cyclical nature of many species on nudibranchs. We have seen it in Janolus fuscus, Flabellina trilineata, Triopha maculata and Triopha catalinae. All at one time or another appearing very abundant, then almost disappearing. And this is why we always look forward to diving and photographing the ever changing underwater environment of the North T-Pier.

Summer, 2011. We have noticed two dramatic changes below the T-Pier this summer: The beautiful nudibranch Janolus fuscus has disappeared. We have not been able either to find its favorite prey, the bryozoan Bugula pacifica, which was earlier plentiful on the pier pilings. Another puzzling disappearance is the beautiful and intricate tube worm: Serpula vermicularis. These intricate and colorful tube worms previously were observed everywhere under the pier: on pilings, rocks, debris, whatever substrate it could find. We haven't seen even one individual in two months. We hope both of these vanishing acts are only temporary.

Spring, 2011. We have again seen many changes over the past few months: The thick living bryozoan clumps seen everywhere under the pier were gone. However, new red bryozoan growth was beginning on many of the pier pilings. The nudibranch Janolus fuscus, which was first seen by us only last year, is now abundant. We see many individuals on the pier pilings feeding on the bryozoan Bugula pacifica, which Janolus fuscus is known to prey upon. (Thanks to Gary McDonald for this information). A nudibranch which we have recently seen in great numbers, Triopha catalinae, has disappeared. The nudibranch Hermissenda crassicornis continues to be abundant and constitutes at least 90% of all the nudibranch life we see.

Fall, 2010. On our most recent dives this Fall, we observed some startling changes. We normally see one or two individuals of the nudibranch species Triopha catalinae. On our most recent dives we saw this beautiful nudibranch everywhere. Along with this change, we did not see any Flabellina trilineata nudibranchs, a species we almost always see many examples of. The other change was the profusion of Lacy bryozoan, Phidolopora pacifica. We saw large clumps of this bryozoa everywhere beneath the T-Pier growing on the sand bottom. Before we most often only saw colonies growing on the pier pilings. Several species of nudibranch were observed in the flutes of the bryozoan clumps, especially Janolus barbarensis.

Summer, 2010. One of the most interesting finds has been the nudibranch Janolus fuscus. This beautiful nudibranch resembles both Janolus barbarensis and Hermissenda crassicornis. We probably have been seeing them but thinking they were variants of hermissendas. They have a blood-red stripe to orange extending about on third of the way down their dorsum. They range from Alaska and Northern Japan to Central California. We have posted two Janolus fuscus images on the nudibranch web page.

January - April 2010. We continue to dive the T-Pier at least twice each month. We have noted some changes, especially in the diversity of nudibranch species. We have had no sightings in several months of the large nudibranch Triopha maculata. Neither have we seen the once common dorids Doriopsilla albopunctata and Archidoris montereyensis. Even the once comon Diaulula sandiegensis is missing. Our thoughts are that the dredging activity may be in part responsible. We hope these species will come back. However, another small but beautiful nudibranch, Flabellina trilineata, is more abundant than ever. We see almost as many of this nudibranch as we do of the still abundant Hermissenda crassicornis.

April - July, 2009. Over the past four months, we have seen several new species and behaviors.  Ken found a cluster of Flabellina trilineata nudibranchs very near our entry point on the pier including egg laying activity.  Previously we have seen only occasional individuals of this beautiful nudibranch species.  We photographed an octopus preying on a clam, and a group of Polycera atra nudibranchs on a hydroid. We have begun to see more and more Polycera atra nudibranchs on our dives.  We continue to photograph Serpulid worms which abound on the pier pilings and beneath the pier.  These amazing organisms are not only beautiful but seen to have different color patterns for almost every individual.  New species seen by us include:  Dendronotus iris, a large crimson colored nudibranch, a brittle star, and a skelton shrimp.  We are also often seeing a lovely red sea cucumber, possibly a slipper sea cucumber (Psolus chitonoides).

March 09.  Monday's dive visibility was poor - about 4 feet with a lot of particulate matter in the water. On Tuesday, visibility improved to about 10 feet.  On both days, the water was very cold, from 45 to 48 degrees, the coldest we have ever experienced in Morro Bay. We are sighting more and more Janolus nudibranchs on our dives.  Also witnessed a blenny capturing and swallowing a sand dab. (See Ken's Dive Log)

--Special thanks for some of those who have assisted us in identifying our underwater critters, including Lisa Needles of Cal Poly, Dave Behrens, author of Pacific Coast Nudibranchs, and Norm Boudreau, former biology teacher at Morro Bay High School.  And a special thanks to Coleen Bondy, who helped us put this web site together, and always answered our calls when problems arose.

 Feb. 09.  Observed a pair of mating Janolus  barbarensis, and three Polycera hedgpethi (this was  only our  second sighting of this nudibranch).

 Jan. 09.  Sighted & photographed a new (to us)  nudibranch: Aegires albopunctatus.  This was the 19th  different species of nudibranch we have recorded  under the pier.  Photographed an unusual eel-like fish: a High  Cockscomb (Anoplarchus purpurescens).  Our first and only sighting of this fish.

 --Nudibranch life seems to be changing, with Hermissendas just as plentiful, but with sightings of several new  species: Acanthodoris rhodoceras, Polycera hedgpethi, and Aegires albopunctatus. Does this mean they have  suddenly appeared, or we just didn't see them before. The beautiful Janolus barbarensis is seen more often  now as well.

 Sept.08.  We were shocked (horrified) to learn a large group of divers had undertaken a 'clean-up' under the T- Pier. This was done evidently with the approval of several agencies. This completely needless and unnecessary  act was done (we think) in ignorance of the special and unique habitat that exists under the pier. The Monterey  Bay Aquarium has coincidently created a special exhibit devoted to the pier/junk habitat and marine creatures  that thrive there, just as they do under the Morro Bay T-Pier.

 July 08.  We have begun to see a few more spotted triopha  (Triopha maculata), mostly juveniles.  These  nudibranchs  were once abundant, with large adults  often seen in the eel grass beds, but then suddenly  disappeared about  two years ago.  Triophas are fascinating animals, often large (for nudibranchs) in a wide  variety of color variations, from deep chocolate brown to pale orange, with raised white spots in larger  individuals.

 May 08.  We identified & photographed four different  Dirona picta nudibranchs.  In our previous 20 years  diving under the pier, we had only spotted one picta.  We also photographed a beautiful Dirona abolineata,  the  first one we had seen here.  While swimming beneath the pier at the end of a dive, Gary was hooked by a  fisherman.  After some effort, he was able to pull and release the hook from his wetsuit while the fisherman,  who thought he had a 'big one' (he did!) tried to pulled him in.  Now we always carry a sharp pair of scissors  attached to our BC's, where we can quickly get them if needed.

 April 08.  We often see octopus under the pier, hiding in bottles, cans, pipes, & clam shells. These intelligent,  often interactive creatures are wonderful photography subjects and can often be seen free-swimming at night in  search of prey.  We noticed that large chunks of red bryozoan  have dislodged and fallen from the pier pilings.  Photographed a large colony of Goose-Necked Barnacles on  one of the pier pilings.  We have not seen this  species before or since.

--When we first began diving here (early 1980's), most pilings were covered with anemones.  Near the pile  bottom, Metridium senile anemones abounded, and up higher, colorful congregating anemones held sway. Over  the years life on the pilings has changed.  Anemones have largely been replaced by red bryozoans, except in the  shallow end of the pier, where large Metridium anemones still abound. We have no idea why red bryozoans has  taken over most of the piling habitat or if this is just a normal cycle in the ocean.  We often see nudibranchs on  the red bryozoans, which makes an excellent backdrop for photography.--

 Jan. 07.  We often see a small but beautiful nudibranch, Flabellina trilineata, one of which adorns our home  page.  These nudibranchs difficult to spot & photograph, but well worth the effort.  Our first sighting of the  cryptic Barred Pipefish (Syngnathus auliscus).  Thin as a wire, these fish often hang out in the eel grass beds that  border the pier on both sides.

--We would be remiss in our duties if we failed to mention the ubiquitous but beautiful nudibranch, Hermissenda  crassicornis.  In the past you always had a good chance of spotting this creature, now you can't miss them. There  are literally thousands of Hermissendas under and around the pier.  We regularly see a few distinct color  variations  in the Hermissenda's cerata and it is common to see mating and egg-laying activity.--

 This page will continue to grow as long as we are able to dive and record life under the Morro Bay T-Pier.



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