Endangered Marine Invertebrates Table 201 Continued Criteria Critically Endangered (CR) individuals in one subpopulation Endangered (EN) Vulnerable (VU) individuals in one subpopulation (b) Extreme fluctuations in number of mature individuals (D) Population size very small or restricted Number of mature individuals Population with a very restricted area of occupancy or number of locations, such that it is prone to human activities or stochastic events within a very short period of time in an uncertain future, and is thus capable of becoming CR or even EN in a very short time period (E) Probability of extinction Probability of extinction in the wild o50 o250 o1000 Area of occupancy: o20 km2 Number of locations: o5 At least 50% within 10 years or generationsb At least 20% within 20 years or generationsb At least 10% within 100 years a Whichever is longer Whichever is longer, and up to a maximum of 100 years in the future Source: Extracted and reorganized from IUCN (International Union for Conservation of Nature) (2011) The IUCN Red List of Threatened Species http://www.iucnredlist.org/ (accessed November 2011) b Table Marine invertebrates classified as threatened or endangered under the U.S Endangered Species Act Species Category (date listed) Range Population status Threats Haliotis cracherodii (Black Abalone) Haliotis sorenseni (White Abalone) Acropora cervicornis (Staghorn coral) Acropora palmata (Elkhorn Coral) Endangered (2009) Endangered (2001) Threatened (2006) Threatened (2006) Northern California to Mexico Southern California to Mexico Florida to Venezuela, including Caribbean Florida to Venezuela, including Caribbean ‘‘Locally extinct’’ in most areas south of Point Conception CA 99% reduction in density since 1970 Declines up to 98% throughout range In many areas, 90–95% reduction in abundance since 1980 Abalone diseases, overextraction (historical), climate change, habitat loss Overextraction (historical); population reproduction failure Coral diseases and climate change, including increased hurricane activity? Coral diseases and climate change, including increased hurricane activity? Source: Reproduced from Environmental Protection Agency (1973) Endangered Species Act, 16 U.S.C y 1531 et seq http://www.epa.gov/lawsregs/laws/esa.html (accessed November 2011) The state of our knowledge on how these phenomena and processes impact on an individual basis, let alone their interactions, on any given species, is such that it is often difficult to determine a single major cause of decline for species widely recognized as threatened (Tables and 3) Human-mediated impacts that are the primary cause of endangerment include habitat destruction and fisheries impacts That said, whether the modern-day surge of critical diseases that have impacted some of the most important reef corals of the Caribbean and the Florida Keys, an abalone disease in California, or stronger and more frequent hurricanes in the Western Atlantic are linked to human-mediated climate change remains unknown (and thus are often discussed without reference to their possible anthropogenic roots), thus potentially obfuscating the overall role of human perturbation Nevertheless, the possibility that climate change (including coastal warming and ocean acidification) and introduced species may play critical roles in the future in species’ endangerment appears clear Table presents only four of the threatened and endangered marine invertebrates currently listed under the ESA by the US National Marine Fisheries Service (NMFS) (NMFS, 2011) and the US Fish and Wildlife Service Table presents the 11 species considered ‘‘critically endangered’’ on the IUCN ‘‘Red List’’ (three of these overlap with the ESA list; one US species, the ‘‘critically endangered’’ coral Porites pukoensis, is not so recognized as even a species of concern by NMFS) In all cases, threats are either referenced generically, unweighted multiple threats are cited, or no threats are noted at all, further underscoring challenges in clearly understanding (and predicting) the demise of even those few species that are on higher profile radars IUCN lists other marine invertebrates as either endangered or vulnerable: one of these is the North American Pacific coast abalone Haliotis kamtschatkana, listed as ‘‘endangered,’’ but, like Porites pukoensis, not so recognized under US law (and, indeed, not recognized under any category, including ‘‘candidate’’ or ‘‘species of concern’’) Not appearing on IUCN lists, or any general lists of endangered species, is the Galapagos seastar Heliaster solaris, last seen in 1977 A commensal pea crab, Enigmatheres canfieldi, likely collected intertidally from a