Cordell Expedition 2023

Northern West Ridge, Photo © 2023 Robert Lee

Project Overview

This document provides consolidated reports and summary of 2023 Field Activities for the Bay Area Underwater Explorers(BAUE) Cordell Exploration and Monitoring project (jointly conducted in partnership with Lee Oceans Foundation), summarizes key findings and observations, and provides a summary of activities. This work was conducted under NOAA ONMS permit# CBNMS-2023-001 and the full report of activities is available here.

The overall goals for the 2023 season were to support Cordell Bank National Marine Sanctuary (CBNMS) education and outreach with refreshed photo and video documentation of various sites at Cordell Bank, and to capture more macro footage of reef scenes and life for use in CBNMS educational and storytelling programming. We were able to conduct four documentation dives and 2 exploratory dives on new sites, and capture hundreds of still photos and hours of conventional video footage.

Location and Activity Summary

During the 2023 project season, BAUE / Foundation divers conducted four days of diving operations at sites across Cordell Bank. We were also able to visit and document two sites that may previously not have been documented (labeled BAUE3 and BAUE4 above, with GPS coordinates below). We conducted the following dives (detailed reports provided in Appendix):

Date	Site	Team	Notes
9/16	Northern West Ridge	R.Lee, A.Lee	Photo, Video
9/16	Northern West Ridge	G.Chilcott, Z.Gwirtz, K.Schapansky	Photo, Video
9/16	Northern West Ridge	J.Heimann, P.Festa	Video
9/16	Cordell BAUE3 (38°2.8073,-123°25.1317’)	R.Lee, G.Chilcott, K.Schapansky	Exploration
9/17	NE Ridge	R.Lee, A.Lee	Photo, Video
9/17	NE Ridge	G.Chilcott, Z.Gwirtz, K.Schapansky	Photo, Video
9/17	Cordell BAUE4 (38°2.43172’,-123°25.2693’)	R.Lee, G.Chilcott, K.Schapansky	Exploration
9/23	Northern West Ridge	R.Lee, A.Lee	Photo, Video
9/23	Northern West Ridge	G.Chilcott, K.Schapansky	Video
9/24	Craine's Point	R.Lee, A.Lee	Video
9/24	Craine's Point	G.Chilcott, K.Schapansky	Video

Fish Life

The most notable observation we had on the fish life this year was the absence of large schools of adult rockfish. In prior years, many sites (e.g. NW Ridge) were heavily populated with schools of adult rockfish, most commonly Widows and to a lesser extent, Blues and Olives. During this year’s visits, we only encountered a few small schools of adults, but instead found large groups of young-of-year(YOY) rockfish. It is unclear if this variation is normal seasonality and variation, or indicative of fluctuations in recruitment cycles or fishing pressure.

The other notable observation was that we encountered, at several sites, decent sized schools of anchovy. In some cases the anchovy were heavily mixed in with YOY rockfish. In other cases, the anchovy were more tightly concentrated in more typical “baitball” type groups.[CORRECTION Jan 3, 2023 - These “anchovy” were later identified as YOY shortbelly rockfish by Tom Laidig]. Aside from schooling rockfish, we noted the typical concentration of long-lived species such as Yelloweye and Boccacio at NW Ridge. We did not see many Quillback this year - only several individuals at NW Ridge. While we did not visit the “Quillback Ridge” location from 2022 which had the largest concentration of Quillback Rockfish, it was notable the lack of Quillback this year. Perhaps this is reflective of the recent fisheries actions taken in response to sampled quillback population declines.

Giant Pacific Octopus

We encountered multiple Giant Pacific Octopus (GPO) individuals at NW Ridge, which was consistent with observations last year, where we saw 2 individuals. Consistent with 2022, we observed one GPO in a den near the top of the NW Ridge structure, near the large crack in the reef where the large school of Boccacio and Rosy Rockfish commonly collect. However, we also found 2 more GPO individuals deeper down off the side of the main pinnacle, around 200’ depth. Both of these GPOs were out in the open, and we were able to get good photo and video documentation of them. One in particular was very curious about the divers and perhaps heat from our lights, and approached to investigate us. While GPO are not abnormal for this area, they are far from commonplace sightings in California, so it is quite unusual to see such a concentration in one area. This will definitely be worth following up in future years to see if we continue to find concentrations of GPO at NW Ridge.

Leucistic / aberrantly colored rockfish

Consistent with the 2022 project season observations, on multiple dives at NW Ridge, we noted several rockfish with various degrees of a distinct and high-contrast mottled black and white coloration pattern. Based on discussion with Milton Love (UCSB) and Tom Laidig (NOAA NMFS Research), these were determined to most likely be a small group of aberrantly colored Blue or Deacon Rockfish. It is interesting to note that no blue or black rockfish exhibiting leucistic color morphs have been observed by BAUE divers during the course of thousands of dives conducted over more than 20 years in the region from Monterey Bay to Pt. Sur. It would be interesting to document the distribution of the leucistic color morph that has now been observed multiple times at Cordell Bank. If this phenotype is numerically significant only at Cordell Bank, it could represent a difference in survivorship of this morph at the respective observation areas. Or, perhaps more interestingly, if the Cordell Bank population contains more leucistic individuals than other California locations it may indicate that there is minimal genetic exchange between populations of this species at Cordell Bank and other areas along the northern and central California coastline

In addition, we continue to observe notable population of the resident Boccaccio rockfish at NW ridge to have pronounced brown spots believed to be ulcers.

Nylon line on NW Ridge

We gathered additional documentation of the nylon line embedded in the reef at NW Ridge. There is at least 50’ visible, but likely with more buried in the substrate and covered with invertebrates, approximately ½” -1” in diameter on the reef. The line is on the top of the NW Ridge reef, and alternates between portions that are covered with invertebrate life, to areas where the bare line is visible, to areas where just the nylon core remains. We located this line in 2022, and upon reviewing photos from our 2016 expedition, we found at least one photo from the same site showing the line as well. So it has been there at least since 2016, and likely longer than that. The line looks consistent with nylon or polypropylene line that one might find on crab pots or used with commercial fishing gear (vs. dockline or other rigging lines). The line is sufficiently embedded in the reef and encrusted with life that removing it would likely do more damage than leaving it; we will continue to document this in future years to see how the encrusting life takes over the line.

Sand Substrate

One of the areas we were asked to document was the sand substrate, to support one of the exhibits and lessons that CBNMS outreach has put together on the subject.Specifically, the interest was in gathering more detailed pictures of the makeup of the sand itself, which was quite interesting. Unlike typical granules of silica sand, we found a very dense collection of tiny shells (or broken bits of shell).

Surface Observations
During our diving days traveling to and from Bodega Bay, we encountered a variety of marine life. Surface conditions were generally calm with winds 10kt or less. We encountered fewer seabirds than we had in the past (a few albatross, shearwater and murres). For marine mammals, we saw fur seals, Dall’s porpoises, CA Sea Lions and humpback whales. Notably, while we saw one or two humpbacks at Cordell Bank itself (and on several dives could hear whalesong underwater). We encountered the majority of the whales about halfway between Bodega Bay and Cordell Bank, unfortunately concentrated around the north-south Vessel Traffic Separation (VTS) lanes. We were showing what looked like significant masses of baitfish on our depth sounder, and the whales were congregating and moving consistent with feeding. We also noted that, consistent with last year, all of the large container ships that we encountered on our transit up and back from Monterey, as well as our project days out to Cordell Bank, were complying with the voluntary vessel speed reduction guidelines (traveling at <10kt).

Team Member	Role
Jim Capwell	Boat Captain
Gavin Chilcott	Diver
Paul Festa	Diver, Video
Zach Gwirtz	Diver, Photo
John Heimann	Diver
Allison Lee	Diver, Video
Rob Lee	Diver, Photo
David Orain	Crew
Kevin Schapansky	Diver, Video
Matt Vandercook	Crew
Ash Whipple	Crew