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An annotated checklist of the fishes of Clipperton Atoll, tropical eastern Pacific
Abstract
Clipperton Atoll is the most isolated, most westerly and largest coral reef in the tropical eastern Pacific (TEP). We collected and recorded fishes to depths of 60m during a two week visit in April 1994. Previous collections were made late last century and by expeditions from Scripps Institution of Oceanography in 1956 and 1958. One hundred and fifteen identified species from 89 genera and 43 families are now known from the island. The most speciose families present at the island are moray eels (Muraenidae, 14 species), jacks (Carangidae, 11 species), wrasses (Labridae, 8 species), surgeonfishes (Acanthuridae, 8 species), squirrelfishes (Holocentridae, 5 species), groupers (Serranidae, 5 species), and triggerfishes (Balistidae, 5 species). These represent ∼14% of the TEP nearshore fish fauna and 40% of its genera. The 115 species include 14 offshore pelagic species, 22 inshore pelagic and midwater species, 70 demersal species that live on hard reef substrata, and nine demersal species that live in or feed on unconsolidated substrata (rubble and sand). Among the 101 non-oceanic species, 68% are carnivores on mobile organisms, 9.2% feed on sessile benthic invertebrates, 12.9% are planktivorous, and 17.8% are benthic feeding herbivores. At least 70 of the non-oceanic species appear to have resident (i.e. self sustaining) populations at the atoll, while 17 species probably are vagrants. Clipperton's fishes include 63 transpacific species (i.e. species that also occur on the western side of the Eastern Pacific Barrier) and 52 species endemic to the TEP. While most (36) of the TEP species occur throughout the region, four occur only at boh Clipperton and the Revillagigedos, the nearest shoal habitat, 950 km to the north. Nine species or subspecies from seven families are endemic to Clipperton. They represent 11.3% of Clipperton's demersal shorefishes. The sister species of one of them likely is a transpacific species, while the sister species of the other eight likely are TEP species.
... Almost all members of the Kyphosidae family are herbivorous [16]. Studies on the diet of K. vaigiensis confirm that this species is a functional herbivore that feeds primarily on macroalgae, including phaeophytes, chlorophytes, and rhodophytes, and almost no animal material [17,18] as other herbivorous species of Kyphosus, such as K. bigibbus, K. cinerascens, K. sydneyanus, K. azureus, and K. elegans (the latter two also from the Gulf of California) [17,[19][20][21]. ...
... Fish sampled in STR were, on average, smaller than in LAP for S. rectifraenum (STR = 11.09 ± 0. 16 (Table 2). (B) ) and between seasons within each location-dry (a) vs. Rainy (b) . ...
In the Gulf of California; mineral deposits have contributed to high metal contents in coastal environments. This study examined cadmium; lead; copper; zinc; and iron contents in three fish species; Kyphosus vaigiensis (herbivore), Stegastes rectifraenum (omnivore), and Balistes polylepis (carnivore) at two mining sites. Metal concentrations were analyzed by atomic absorption spectrophotometry and stable nitrogen and carbon isotopes were estimated using mass spectrophotometry. Also, we assessed the risk to human health from the consumption of these three species based on permissible limits; although only two of them (Kyphosus and Balistes) are consumed as food. Metal concentrations differed among fish species; except for iron. The highest concentrations of metals were not always recorded in the species at the highest trophic level; i.e., Balistes. The highest concentrations (dry weight) recorded were cadmium (0.21 ± 0.03 µg g−1) and lead (1.67 ± 0.26 µg g−1), in S. rectifraenum; copper (1.60 ± 0.49 µg g−1) and zinc (67.30 ± 8.79 µg g−1), in B. polylepis; and iron (27.06 ± 2.58 µg g−1), in K. vaigiensis. Our findings show that each element accumulates differently in particular marine organisms; depending on the physiology of the species and the biogeochemistry of its habitat; which in turn is affected by the anthropogenic activities in adjacent areas. No risk of heavy metals toxicity is expected from the human consumption of the species and sites studied
... The position of Clipperton samples as peripheral to and most closely related to the Revillagigedo in the haplotype network indicates that the Clipperton population of S. xyris likely was founded by specimens from Revillagigedo Islands. The dispersal of fish species from the Revillagigedo Islands to Clipperton Atoll has been previously reported, with vagrant Holacanthus clarionensis Gilbert, 1890, which is endemic to the Revillagigedo Islands (Allen and Robertson 1997;Robertson et al. 2023). In addition, waifs of H. passer Valenciennes, 1846 which is widely disrtributed on the mainland, Cocos, Malpelo, and the Galapagos, occasionally reach Clipperton Atoll (Clua and Planes 2019), most likely originating from the mainland as that species is a vagrant at the Revillagigedo Islands. ...
The tropical eastern Pacific (TEP) is a biogeographic region with a substantial set of isolated oceanic islands and mainland shoreline habitat barriers, as well as complex oceanographic dynamics due to major ocean currents, upwelling areas, eddies, and thermal instabilities. These characteristics have shaped spatial patterns of biodiversity between and within species of reef and shore fishes of the region, which has a very high rate of endemism. Scorpaenodes xyris, a small ecologically cryptic reef-dwelling scorpionfish, is widely distributed throughout the TEP, including all the mainland reef areas and all the oceanic islands. This wide distribution and its ecological characteristics make this species a good model to study the evolutionary history of this type of reef fish across the breadth of a tropical biogeographical region. Our evaluation of geographic patterns of genetic (mitochondrial and nuclear) variation shows that S. xyris comprises two highly differentiated clades (A and B), one of which contains four independent evolutionary subunits. Clade A includes four sub-clades: 1. The Cortez mainland Province; 2. The Revillagigedo Islands; 3. Clipperton Atoll; and 4. The Galapagos Islands. Clade B, in contrast, comprises a single unit that includes the Mexican and Panamic mainland provinces, plus Cocos Island. This geographical arrangement largely corresponds to previously indicated regionalization of the TEP. Oceanic distances isolating the islands have produced much of that evolutionary pattern, although oceanographic processes likely have also contributed.
... The silvertip (ST) shark Carcharhinus albimarginatus is one of the most abundant predator species found in Revillagigedo and Clipperton MPAs (Allen and Robertson, 1997;Lara-Lizardi, 2018). This is a large slow-growing shark, from 0.63 to 0.68 m in total length (TL) at birth to a maximum body size of 3 m TL. ...
... For the latter, a new species (O. clippertonensis Springer, 1962) has been recognized for Clipperton Atoll, a small isolated island at the western edge of the TEP (Allen & Robertson, 1997). In contrast, for some, the separation into two species is not possible or even questionable including the nurse shark Ginglymostoma cirratum (Bonnaterre, 1788), the lemon shark Negaprion brevirostris, the leatherjacket Oligoplites saurus (Poey,1868) the yellowfin mojarra Gerres cinereus (Walbaum, 1792) and the fringed flounder Etropus crossotus Jordan & Gilbert 1882; these are remarkably similar in external morphology, but also in their behavior and ecology (Castro-Aguirre et al., 1995;Thomson et al., 2000). ...
Background:
One of the most relevant topics in ecology and evolution is understanding the relationship between biological and functional diversity at the ecosystem level; both important in the evolutionary processes and the structuring of complex communities.
Goals:
In this essay, the explanatory hypotheses focused on global patterns of the distribution of species are described along with selected hypotheses relating species richness/biodiversity to ecosystem function, and the differentiation of the terms guild and functional group are discussed.
Methods:
Both biodiversity and functional diversity are key in the evolutionary processes and the structuring of complex communities and thus examples of functional equivalence of convergent evolution derivatives are presented in terms of the form and ecological habits of fishes of the Tropical Eastern Pacific Ocean. Finally, the importance of redundancy in ecosystem functioning is examined as well as the impact of environmental disturbances on ecosystem function.
Results:
In general, systems with low species richness and redundancy within functional groups are more vulnerable to disturbances. However, despite the extensive effort to understand the relationship between species richness/biodiversity and ecosystem functioning, there is no consensus on the effect of species loss on the functioning of the ecosystem. Some hypothesize that each species is unique and plays a unique role in the ecosystem whereas alternate hypotheses indicate that species overlap in function supporting sustainability at the ecosystem level, such that the removal of one species function may be replaced by another.
Conclusions:
The most widely accepted concept is that a greater number of species increases the efficiency in the use of resources and also provides resilience against environmental changes or impacts through functional redundancy.
... Interestingly, in this case, the fact that the MTL was higher for the Revillagigedo Archipelago than for Clipperton atoll indicates higher fishing pressure in the latter area. The lower value at Clipperton could be due to the fishing, often illegal, that has been carried out in recent years at this site (Allen & Robertson, 1997;Béarez & Séret, 2009), although illegal fisheries also seem to occur at Revillagigedo. ...
Revillagigedo Archipelago and Clipperton atoll are oceanic islands located in the eastern tropical Pacific. The composition and trophic structure of their fish assemblages have never been characterized in detail, and the aim of this study was therefore to analyse the community structure and assess the similarity of fish assemblages between these two areas. Underwater visual fish censuses were conducted using band transects at two depth levels in three islands of the Revillagigedo Archipelago (Socorro, San Benedicto, and Roca Partida) and at Clipperton atoll. We calculated ecological indices (density, richness, Shannon diversity, Pielou evenness, and taxo-nomic distinctiveness) for each transect. These were compared in order to determine quantitative differences among the islands and bathymetric levels. Qualitative analyses (ANOSIM, nMDS, and SIMPER) were also performed. Finally, we analysed the trophic structure of the assemblages and the functional diversity of the four studied sites. The results showed significant differences for all indices, except diversity (H′). Roca Partida was the site with greatest abundance and richness due to the presence of pelagic species in large numbers. No significant differences were found in functional diversity, suggesting a high degree of ecological redundancy. Lower-level car-nivores with mean trophic level values of between 3.3 and 3.8 dominated both areas. The ordination analysis did not show a clear difference in fish composition among the islands, although Clipperton atoll has a particular fauna characterized by endemic species (Thalassoma robertsoni and Stegastes baldwini). In conclusion, the fish communities of the studied areas seem quite similar, but their assemblage structure differs. In particular, Clipperton is differentiated by the influence of endemic species.
KEYWORDS: ecological index, ecological redundancy, Ichthyofauna, National Park, nMDS, trophic level
We present a comprehensive and update checklist systematic of the icthyofauna of this insular region, which is comprised by 366 species, 241 genera, 101 families, 28 orders and tree classes. The families with the most richness specific were: Carangidae (20 spp.), Serranidae (19) and Muraenidae (18). Socorro Island was recorded 220 species, Clarion Island 179, San Benedicto Island 128; followed by Roca Partida Island 62. This diversity as well as endemic species number is relationship with the surface of each island. There is a higher similarity ictiofaunistic between Clarion Island and Socorro Island; while, the lowest similarity was between San Benedicto Island and Roca Partida Island. The ichthyogeography of the Revillagigedo Archipelago has a higher affinity with the Panamic province (42.3%), followed by the Cortes (41.5%). A higher number of species are of the wide distribution (circumglobal: 21 %; amphipacific 22.4 %). Also, endemic species are represented by 26 species (7.1%).
Clipperton Atoll (Île de La Passion) is the only atoll in the Tropical Eastern Pacific (TEP) ecoregion and, owing to its isolation, possesses several endemic species and is likely an important stepping stone between Oceania, the remainder of the TEP, including other oceanic islands and the west coast of Central America. We describe the biodiversity at this remote atoll from shallow water to depths greater than one thousand meters using a mixture of technologies (SCUBA, stereo baited remote underwater video stations, manned submersible, and deep-sea drop cameras). Seventy-four unique taxa of invertebrates were identified during our expedition. The majority (70%) of these taxa were confined to the top 400 m and consisted mostly of sessile organisms. Decapod crustaceans and black corals (Antipatharia) had the broadest depth ranges, 100–1,497 m and 58–967 m, respectively. Decapods were correlated with the deepest depths, while hard corals were correlated with the shallow depths. There were 96 different fish taxa from 41 families and 15 orders, of which 70% were restricted to depths <200 m. While there was a decreasing trend in richness for both fish and invertebrate taxa with depth, these declines were not linear across the depth gradient. Instead, peaks in richness at ∼200 m and ∼750 m coincided with high turnover due to the appearance of new taxa and disappearance of other taxa within the community and is likely associated with the strong oxygen minimum zone that occurs within the region. The overall depth effect was stronger for fishes compared with invertebrates, which may reflect ecological preferences or differences in taxonomic resolution among groups. The creation of a no-take marine reserve 12 nautical miles around the atoll in 2016 will help conserve this unique and relatively intact ecosystem, which possesses high predator abundance.
The Whitespotted boxfish Ostracion meleagris Shaw, 1796 is a reef resident distributed along the Indo Pacific, but at the Baja California Peninsula, Mexico, this fish has been reported only in the southern region, with a northern limit at 24.2°N inside the Gulf of California. Here we document the presence of O. meleagris in 17 sites along the central gulf, with an extreme record at Tortuga Island (27.445°N, almost 400 km north of its accepted range), and also in two locations of the western Baja California Peninsula (Alijos Rocks and Puerto San Carlos, at 24°N). These findings represent more examples of a recently observed trend in which several species of tropical fish have expanded their distribution range towards the inner Gulf of California and in the Pacific side of the peninsula, as a possible response to the reported warming that occurs in the region.