Quote:
Originally Posted by marduc
The ban for the entire genus Caulerpa was because California lawmakers in their infinite wisdom decided that it may be too difficult to differentiate between Taxifolia and other Caulerpa species since they all look so similar  . |
From two studies.
A FORENSIC AND PHYLOGENETIC SURVEY OF CAULERPA SPECIES (CAULERPALES,
CHLOROPHYTA) FROM THE FLORIDA COAST, LOCAL AQUARIUM SHOPS, AND
E-COMMERCE: ESTABLISHING A PROACTIVE
BASELINE FOR EARLY DETECTION
Abstract: ". Surveys in central Florida and southern California of 4100 saltwater aquarium shops and 90 internet sites revealed that >50% sold Caulerpa. Of the 14 Caulerpa species encountered, Caulerpa racemosa was the most common, followed by Caulerpa sertularioides, Caulerpa prolifera, Caulerpa mexicana, and Caulerpa serrulata. None of the 4180 field-collected individuals (representing 13 species) was the invasive strain of Caulerpa taxifolia or C. racemosa. With one exception (a sample of C. racemosa from a shop in southern California belonged to the invasive Clade III strain), no invasive strains were found in saltwater aquarium stores in Florida or on any of the internet sites. Although these results are encouraging, we recommend a ban on the sale of all Caulerpa species (including ‘‘live rock’’) because: morphological identification of Caulerpa species is unreliable (412% misidentification rate) and invasive strains can only be identified by their aligned DNA sequences, and because the potential capacity for invasive behavior in other Caulerpa species is far from clear"
6 years later...
Effectiveness of the California State Ban on the Sale of Caulerpa Species in Aquarium Retail Stores in Southern California
Abstract: "The invasion of the aquarium strain of the green alga Caulerpa taxifolia and subsequent alteration of community structure in the Mediterranean Sea raised awareness of the potential for non-native seaweeds to impact coastal communities. An introduction of C. taxifolia in southern California in 2000, presumably from the release of aquarium specimens, cost ~$7 million for eradication efforts. Besides C. taxifolia, other Caulerpa species being sold for aquarium use also may have the potential to invade southern Californian and U.S. waters. Surveys of the availability of Caulerpa species in southern California aquarium retail stores in 2000–2001 revealed that 26 of 50 stores sold at least one Caulerpa species (52 %) with seven stores selling C. taxifolia. In late 2001, California imposed a ban on the importation, sale, or possession of nine Caulerpa species; the City of San Diego expanded these regulations to include the entire genus. To determine the effectiveness of the California ban, we resurveyed Caulerpa availability at 43 of the 50 previously sampled retail stores in southern California in ~2006, ~4 years following the ban. Of the 43 stores, 23 sold Caulerpa (53 %) with four stores selling C. taxifolia. A χ2 test of frequency of availability before and after the California ban suggests that the ban has not been effective and that the aquarium trade continues to represent a potential vector for distributing Caulerpa specimens, including C. taxifolia. This study underscores the need for increased enforcement and outreach programs to increase awareness among the aquarium industry and aquarium hobbyists.
I paste these two to show that the industry can't reliably identify species. I know, it sucks. It's on us to email these folks and say "actually, what you're selling is...". It's especially bad when stores try to get cutesy with macroalgae names as if these are zoas.
It is also important to note that we cannot predict with any reliability what species will become invasive. It depends on the traits of the would-be invader, the traits and structure of the receiving community, and the environmental conditions (salinity, ph, temp, etc). Since Caulerpa share many traits, it is
precautionary to assume those traits which allow for successful invasion may be shared across congeners. The nice thing about precautionary, is it holds until it can be discarded. But we don't have an industry organization that funds research for the benefit of the hobby...