Blacksmith (Chromis punctipinnis) Newly Abundant in Central California

"In the midfield of my dive this school of blacksmith suddenly appeared. They were hiding from cormorants that dove into the water."

Tom Okey wrote:

A large school of the subtropical damselfish 'blacksmith' (Chromis punctipinnis) was documented in video by Weiwei Gao in the kelp forests of the Edward F. Rickets State Marine Conservation Area---along the shore of Monterey, California in August of 2019. I consider C. punctipinnis to be a 'southern California bight' species, which I observed to be abundant in the kelp canopies around the San Diego area and southern California's Channel Islands during intensive diving there during the late 1980s (1986-1989). I also observed that this species was not at all conspicuous in the Monterey and Carmel Bay Areas (or the Big Sur Coastline), including in the kelp forests off Monterey, during 1988-1992 when I dove frequently and extensively in those areas. Indeed, they were not ecologically present meaning that if they were present at all they were very uncommon and thus not a functioning part of the ecosystem.

The occurrence records of this species on Fishbase are all from Southern California and Mexico, as reflected by the modeled distribution on Aquamaps, which barely extends to Monterey (but it is unclear from the underlying point map how recent the most northern observation points are). The first iNaturalist observation of C. punctipinnis north of Point Conception (which delineates southern and central California marine ecosystems) was in 2015 at the same location of Weiwei Gao's video---a very popular sport diving location. There have been a few C. punctipinnis observations at the same location since 2015 documented on iNaturalist.

Summaries for this species on both Fishbase and Wikipedia describe the ranges as Monterey Bay in California, USA to central Baja California, Mexico, which is true presently, but the apparent source of this information---the observations documented in Fishbase---do not include any historical observations from north of Point Conception. Miller and Lea (1972) do identify the range of C. punctipinnis as extending from San Pablo, Baja California to Monterey, but they specified that they were "Common in southern California, uncommon north of Pt. Conception."

Thus, my personal observation is that the abundance and ecological presence of blacksmith (C. punctipinnis) in central California has considerably increased since 1988-1992, indicating an ecologically significant northward shift in this fish species. This observation and inference is consistent with all of the aforementioned evidence.

Weiwei Gao's video also features a Hoodwinker sunfish (Mola tecta)---apparently newly arrived from the southern hemisphere---being cleaned by an aggregation of Seniorita wrasse (Oxyjulis californica), which is also a subtropical 'southern California bight' species. See the forthcoming LEO Network observations about these species. I conclude that this single video by Weiwei Gao demonstrates a major shift of Monterey Bay nearshore kelp forest ecosystems from a temperate fauna to a subtropical fauna during the last 25 years.

Weiwei Gao wrote:

I am not a fish expert. Instead I was just cruising in and out of the kelp forest looking for beautiful scenes. This dive was made in an early afternoon and in the midfield of my dive this school of blacksmith suddenly appeared. They were hiding from cormorants that dove into the water. I was pretty happy about the encounter without thinking much about the science behind. The same happened to the mola. As I remember, the first prize video of the shootout also had a clip of the blacksmith, which looked similar to what I captured.

Literature Cited

Miller, D.J. and Lea, R.N., 1972. Guide to the coastal marine fishes of California. Cal. Dep. Fish Game. Fish Bull, 157, pp. 249.