Point Fermin Long-Term trends | MARINe

Point Fermin Long-Term trends

See below for trend graphs

In order to standardize species resolution across all MARINe groups, and over time, some species (typically rare) were lumped for graphical presentation of Long-Term monitoring data. See lumped categories for definitions (some variation occurs between methods and over time). Due to funding constraints, semi-annual sampling of plots/transects was reduced to annual sampling beginning in 2016.

Barnacle cover in the Chthamalus/Balanus barnacle plots at Point Fermin has consisted primarily of Chthamalus dalli/fissus (note that Chthamalus and Balanus species were not distinguished until 2001). Cover of Chthamalus typically varied inversely with bare rock cover, with relatively little else occurring in these plots. Initial cover when the site was established in fall 1999 was ~60% but declined to ~40% by spring 2003. Barnacle cover increased in fall 2003 and remained relatively high through fall 2006, peaking at nearly 80%. Chthamalus cover then declined again starting in 2006, reaching a low of ~20% in 2009. Since 2009, barnacle cover has remained relatively consistent, ranging between 30-40%. Motile invertebrate counts at this site were conducted twice per year (fall and spring) from 2000 through 2003, and counts were conducted annually starting in 2004.  Counts of Littorine snails were added to the protocol in the fall of 2001. Within the barnacle plots, Littorines have been very abundant, consistently around 1,000 individuals per plot. Limpets have also been common with up to 50 individuals per plot, except in 2010 with a large drop in abundance. Sampling of motile invertebrate counts was halted after spring 2014.

Mussels (Mytilus) have declined substantially in plots at Point Fermin, quickly decreasing from ~100% initial cover when the site was established in 1999 to 40-50% by 2001. The decline slowed through 2003, when cover reached ~15%, then stabilized until 2010. Following 2010, Mytilus cover slowly declined again, reaching near zero. These plots are representative of the surrounding reefs as widespread mussel bed contractions have occurred at this site, a phenomenon that has been reported elsewhere in southern California. As mussel cover declined, bare rock, non-coralline crusts, and barnacles became more prevalent, as did other taxa (e.g. Tetraclita, Lottia gigantea, chitons, crustose algae, and articulated coralline algae) not indicated in the figure due to low relative contributions to overall cover. The non-native red alga Caulacanthus also was somewhat common in the wetter cracks and crevices of mussel plots. Motile invertebrate counts initiated in plots in 2000 indicated that limpets, chitons (Nuttalina spp.) and shore crabs (Pachygrapsus crassipes) were all present initially at similar abundances, each with ~10 individuals per plot. As mussels declined, limpet abundance increased dramatically to around 1,000 individuals per plot while shore crabs have been relatively uncommon (<1 individual per plot). Chiton abundance has remained steady throughout the sampling years. Sampling of Littorine snails began in 2006 with densities being generally low (<10 individuals per plot).

Within rockweed plots, Silvetia compressa cover has been seasonally variable (lower in spring and higher in fall) with the mean cover remaining steady near 100% (fall highs) for the first 5 years of sampling. Starting in 2005, cover declined gradually with fall highs dropping to ~50% by 2013. Rockweed cover continued to decline, reaching below 40% in 2015, before recovery to above 80% by late 2017. The seasonal pattern observed during the first 15 years of monitoring has not been present since 2014. As Silvetia cover has declined, bare rock cover has become more prevalent, as has the cover crustose algae and the non-native red alga Caulacanthus. Motile invertebrate counts indicate the presence of a diversity of taxa that vary greatly in numbers among sampling seasons. In the early years when motile invertebrates were counted seasonally, Cyanoplax chitons (including Cyanoplax hartwegii) that are common under the rockweed canopy exhibited seasonal variation in synchrony with Silvetia seasonal patterns. Following the switch to once-per-year sampling, the spring abundance was relatively stable, despite declines in Silvetia cover during that time. Hermit crab (Pagurus spp.) numbers were high and variable during the early years but then dropped to zero by 2004. Turban snails (Tegula funebralis) were less common through 2007 but increased to between 20-40 individuals per plot from 2008 to 2013; none were found in 2014 before motile invertebrate sampling was halted. Limpet densities were highly variable throughout the years with high numbers in 2006 and between 2011-2013. Littorines and limpets were not sampled in 2014.

Rock ("Above Barnacles") plots were added to this site in the fall of 2008 to document any upward spread of intertidal species as a result of sea level rise or other factors. These plots were expected to remain dominated by bare substrate unless barnacles or other species shifted their zonal ranges higher into the splash zone. From their inception, a few barnacles have been recorded within plots, most within cracks and crevices. However, bare rock cover has consistently dominated the plots.

Surfgrass (Phyllospadix spp.) cover from transect sampling has shown relatively consistent seasonal variation (lower in spring, higher in fall), with moderate fluctuations in cover in the fall seasons between 60-80%. Surfgrass cover reached its lowest levels (20-40%) in spring sampling in 2000, 2007, and 2014 with peaks in cover above 80% in more recent years (2016 to 2018). Common seaweed taxa in the surfgrass zone have also exhibited seasonal variation with the cover of the feather boa kelp Egregia generally following Phyllospadix seasonal patterns, although to a lesser degree. Since 2015, Egregia cover has been relatively low. Red algae and articulated corallines generally displayed an inverse seasonal pattern, with cover of both taxa remaining consistently low starting in 2015.

Sea star (Pisaster ochraceus) plots were added to this site in the spring of 2003 and consist of three large irregular plots surrounding an area of medium relief rock, which includes several cracks and ledges. Seastars were common at this site when these plots were initiated but declined steadily over the next two years; only a few seastars were counted and measured each season from 2005 to 2013. These plots are likely representative of the site as a whole given concurrent sitewide searches also yielded few seastars. The seastar wasting disease struck this site some time in advance of our fall 2013 sampling based on other local reports of diseased stars subtidally and a die-off of seastars at the adjacent Cabrillo Marine Aquarium. During our Fall 2013 sampling, no seastars could be found at the site, either in the fixed plots or in sitewide searches. No seastars have been found in plots through 2018. The size measures of seastars indicated a high frequency of small seastars during the first sampling seasons in 2003, possibly due to a large recruitment pulse occurring in preceding years. By spring 2004, the size distribution exhibited a relatively even frequency among small to large sized individuals. Recruitment has been low since 2004, except a few small individuals in 2006/2007.

Photo Plots

Long-Term methods Photo Plot thumbnail

Below are the trends observed for each Photo Plot target species at this site. Long-Term percent cover trend graphs also include any species that reached a minimum of 25% cover during any single point in time within a given target species assemblage. Breaks in trend lines represent missed sampling events. For additional species observed that did not meet this 25% threshold, please use the Interactive Map.

For motile invertebrate Species Counts, a mean across all plots was calculated, and only those species with a value of at least 5 individuals for at least one sample are shown. Due to time constraints, motile invertebrate counts have not been done at most sites since 2012. For motile invertebrate size trend graphs by site, please use the Interactive Map.

Chthamalus/Balanus (Acorn Barnacles) - percent cover

Point Fermin barnacle trend plot

Chthamalus/Balanus (Acorn Barnacles) - motile invertebrate counts

Point Fermin barnacle trend plot

Mytilus (California Mussel) - percent cover

Point Fermin Mytilus trend plot

Mytilus (California Mussel) - motile invertebrate counts

Point Fermin Mytilus trend plot

Silvetia (Golden Rockweed) - percent cover

Point Fermin Silvetia trend plot

Silvetia (Golden Rockweed) - motile invertebrate counts

Point Fermin Silvetia trend plot

Rock (Above Barnacles)

Point Fermin rock trend plot

Rock (Above Barnacles) - motile invertebrate counts

Point Fermin rock trend plot


Long-Term methods Transects thumbnail

Below are the trends observed for each Transect target species at this site. Long-Term trend graphs also include any species that reached a minimum of 25% cover during any single point in time within a given target species assemblage. Breaks in trend lines represent missed sampling events.

Phyllospadix (Surfgrass)

Point Fermin surfgrass trend plot

Species Counts and Sizes

Long-Term methods Counts thumbnail

Species Counts and Sizes (where recorded) for Pisaster are shown below for this site. At some sites, other sea star species and Katharina are counted in addition to Pisaster. The sum of all individuals across all plots is displayed. Note that data gaps are represented by breaks in long-term count trend lines, but are not shown in size plots.

Pisaster (Ochre Star) - counts

Point Fermin Pisaster trend plot

Pisaster (Ochre Star) - sizes

Point Fermin Pisaster size plot