Corresponding author: D Ross Robertson (
Academic editor: Kyle Piller
Cayo Arcas is a small, offshore reef complex on the southwest corner of Campeche Bank, Gulf of Mexico. The only published information (from 2000) on the fishes of that reef refers to 37 species. Here additional information is added, some from unpublished observations during the 1980s, as well as author observations made during 2013 and 2016. These bring the checklist of that reef’s fishes up to 162 species. The possible effects of the limited number of fish habitats available at Cayo Arcas on the composition of its fish fauna are discussed. The Indo-Pacific damselfish
Robertson DR, Perez-España H, Lara EN, Itza FP, Simoes N (2016) The fishes of Cayo Arcas (Campeche Bank, Gulf of Mexico): an updated checklist. ZooKeys 640: 139–155.
The southwest Gulf of Mexico has relatively few coral reefs. Only a small number of these are offshore reefs on the broad, shallow Campeche Bank that extends 200+ km north from the Yucatan Peninsula. These include Alacran Reef, and a set of about 10 small submerged banks and emergent reefs scattered along the western edge of that bank (
Location of Cayo Arcas in the Gulf of Mexico (Base map: NOAA).
Here an updated checklist for the fishes of the Cayo Arcas reef complex is presented that draws on both old and new information. The object of publishing this checklist is to improve understanding of the distributions of reef fishes in the southwest Gulf of Mexico, which hosts a number of endemic reef fishes, has a different marine environment to the rest of that gulf (
This updated list is not complete, because the dives on which it is based did not provide comprehensive coverage of fishes across the full range of habitats available. Furthermore, because the list is based on diver observations, cryptic fishes that live within the reef matrix or within fringing soft sediments undoubtedly are under-represented. The only really effective way to comprehensively sample such fishes, which represent as much as half of any reef-associated fauna in the neotropics, is with the use of small ichthyoside stations (
The Cayo Arcas reef complex is situated at
Schematic representation of Cayo Arcas reef complex. Solid lines indicate edges of emergent reef. Solid fill = sand cays. Locations of dives sites for 2013 and 2016 are indicated by symbols.
Mangroves and beds of seagrasses (turtlegrass,
The earliest information available on Cayo Arcas fishes comes from an unpublished Master’s thesis by
Table
Preliminary checklist of fishes observed at Cayo Arcas, Campeche Bank. Abundance and distribution in 2016: Rare (1 seen during expedition); Uncommon (< 5); Occasional (~ 20, at multiple dive sites); Common, widespread (scores, at most/all dive sites); Locally common (scores to hundreds at 1–2 dive sites); Abundant, widespread (hundreds to thousands at most/all dive sites); Platform (present on oil-loading platform 1.5 km from reef complex). Abundance 2013: Mean no. fish/transect by HP-E and ENL (see methods); Abundance 1984-86: G&C 2000 =
Taxon | Abundance and distribution 2016 | Abundance 2013 HP-E/ENL | Abundance 1984-86 |
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Rare | ||
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Uncommon | 0/0.1 | ||
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0/0.1 | ||
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Locally common (schools); platform | 0/0.2 | |
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Uncommon | ||
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Rare | 0/0.1 | |
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Locally common (large schools) | |||
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Locally common (large schools) | ||
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Common, widespread | 0.097/0.250 | |
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Occasional, widespread | 0/0.9 | |
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Uncommon | ||
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Uncommon | ||
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Uncommon | 0.042/0.125 | 0/0.2 |
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Occasional, widespread; platform (species note) | ||
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Common, widespread; platform | 0.042/0.125 | 0/0.2 |
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0.014/0.042 | 0/0.3 | |
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Common, widespread | 0.055/0.083 | 0/1.1 |
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Common, widespread | 0.111/ 0.333 | 0.05/1.0 |
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Locally common | ||
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Locally common | ||
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0.014/0 | ||
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Uncommon | ||
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Rare | ||
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Occasional, widespread | 0.028/0.083 | 0/0.1 |
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Occasional, widespread | 0.097/0.250 | 0/0.4 |
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Rare | ||
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Rare | ||
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Common, widespread; platform | 0/1.0 | |
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Locally common | ||
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Uncommon | ||
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Uncommon | 0.014/0.042 | |
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Occasional, widespread | 0.014/0.042 | 0/0.4 |
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Locally common (aggregations); platform | ||
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Rare | ||
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Locally common | ||
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Common, widespread | 0.083/0.167 | 0/0.7 |
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Locally common (aggregations) | ||
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Common, widespread | 0.139/ 0.208 | 0.10/0.7 |
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0/0.1 | ||
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Locally common (aggregations) | 0.028/0 | |
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Rare; platform only | ||
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Uncommon (small schools) | ||
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Common, widespread (aggregations) | 0/0.3 | |
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Common, widespread (aggregations) | 0.028/0 | |
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Uncommon (aggregation); platform only | ||
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Locally common (aggregations) | 0.305/0.208 | 0.05/0.7 |
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Locally common (school) | ||
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Rare | ||
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Locally occasional | 0/0.1 | |
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(Species note) | 0.05/0.1 | |
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Occasional (juveniles) | ||
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Common, widespread; platform | 0/1.2 | |
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Common, widespread | 0.028/0.083 | |
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Occasional, widespread | 0/0.1 | |
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Occasional (juveniles) | ||
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Abundant, widespread; platform | 2.619/7.333 | 0.05/1.1 |
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Uncommon | 0.014/0.042 | 0/0.1 |
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Locally common (school) | 0.05/0 | |
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Locally common (schools) | ||
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Common, widespread (aggregations) | 0.014/0 | 0.05/0 |
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Uncommon | 0.05/0 | |
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Locally common (schools) | 0.05/0.4 | |
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Common, widespread | 1.067/1.125 | 0.73/2.4 |
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Uncommon | 0/0.7 | |
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Uncommon | ||
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Uncommon | 0.083/0 | 0.05/0 |
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Uncommon | 0.05/0.4 | |
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Locally common (large schools) | ||
Locally common (large schools) | 1.386/0 | 12.83/1.7 | |
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Common, widespread | 0.055/0 | |
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Common, widespread | ||
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Uncommon | ||
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Uncommon | ||
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Common, widespread (schools) | 0.014/0.083 | 0/2.4 |
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Locally common | 0.028/0 | |
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Locally common (aggregations) | ||
3.672/1.542 | |||
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Occasional | ||
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Common, widespread | ||
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Common, widespread | 0/0.5 | |
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Common, widespread | ||
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0/0.2 | ||
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Occasional | ||
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Common, widespread | 0.194/0.458 | 0/1.5 |
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Common, widespread | 0.152/0.250 | |
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Uncommon | ||
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Common, widespread; platform | 0/0.4 | |
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0.05/0 | ||
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Locally common | 0.055/0 | 0/1.2 |
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Locally common | 0.014/0.042 | 0.05/0.5 |
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Rare; platform only | ||
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Locally abundant, widespread | 1.108/1.167 | 7.16/2.1 |
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Locally common | 0.430/0 | 0.05/0.2 |
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Locally common | 0.028/0.083 | 0/0.2 |
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Abundant, widespread | 47.056/ 90.750 | 28.93/3.2 |
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Common, widespread; platform | 0.194/0 | |
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Common, widespread | 0.152/0.375 | 1.14/2.3 |
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Abundant, widespread (aggregations); platform. (species note) | Present/0 | |
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Abundant, widespread (species note) | 0.443/0.167 | |
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0.055/0.167 | 1.14/1.4 | |
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Locally common | 0.222/0.417 | 0/0.3 |
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Abundant, widespread; platform | 3.603/4.667 | 0.05/0.9 |
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Abundant, widespread | 0.679/1.500 | 12.93/3.7 |
Abundant, widespread (species note) | 0.679/0.542 | 0.05/0 | |
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Locally common; platform only | ||
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Common, widespread | 0.651/1.208 | 0/1.1 |
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Locally common, schools | 1.261/3.792 | 9.73/0.4 |
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Very common, widespread | 0.443/0.083 | 0/0.9 |
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Abundant, widespread (species note) | 5.085/0.083 | |
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Common, widespread | 2.245/4.452 | 0.05/0.2 |
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Common, widespread | 0.402/1.208 | 1.36/1.3 |
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0.319/0 | ||
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Common, widespread | 0.222/0.083 | 0/1.0 |
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Uncommon | ||
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Abundant, widespread; platform | 10.752/11.833 | 1.22/2.1 |
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Uncommon; local | ||
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Occasional | ||
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Occasional | 0/0.6 | |
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Common, widespread | 0.152/0 | 0.05/1.6 |
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Occasional, widespread | 0.042/0 | 0/0.3 |
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Common, widespread | 2.480/3.042 | |
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Common, widespread | 0.111/0.333 | 5.40/1.3 |
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Common, widespread | 1.178/2.875 | 5.23/3.4 |
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Locally common | 0.055/0.167 | |
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Common, widespread | 1.857/2.833 | 0/0.4 |
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Occasional, widespread | 0.014/0.042 | 0.05/1.7 |
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Common, widespread | ||
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Locally common | 0.291/0.500 | 0/1.5 |
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Very common, widespread | 1.136/1.833 | 3.63/3.2 |
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Present (species note) | ||
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Uncommon; platform only | ||
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Locally common; platform only | ||
Common, widespread | 0.028/0 | 0/01.2 | |
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Locally common; platform | ||
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Locally common; platform only | ||
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Locally common | ||
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Common, widespread | ||
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Common, widespread | 0.097/0.083 | |
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Present (species note) | ||
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Abundant, widespread | ||
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Abundant, widespread | 0.319/0 | |
Abundant, widespread (species note) | 4.432/5.625 | ||
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Common, widespread | 0.222/0.292 | |
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Uncommon | ||
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Abundant, widespread | 0.249/0.042 | |
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Locally common (aggregations) | ||
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Common, widespread | 0.097/0.167 | 0.05/0.8 |
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Common, widespread | 0.139/0.250 | 0.05/1.6 |
Common, widespread (species note) | 0.291/0.875 | 1.09/1.2 | |
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Occasional, widespread | 0.014/0.042 | 0/1.1 |
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Rare | ||
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0.042/0.125 | ||
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Occasional, widespread | 0/0.1 | |
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Locally common | 0/0.2 | |
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0/0.2 | ||
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Occasional, widespread | 0/0.3 | |
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Rare | 0.028/0 | |
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Locally common | 0.028/0 | |
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Rare | 0/0.1 | |
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Occasional, widespread | 0.014/0.042 | 0/0.8 |
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Common, widespread | 0.152/0.250 | 0.05/0.8 |
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Rare | ||
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Uncommon | 0/0.4 |
Taxonomic notes:
The present checklist includes 162 species from 41 families. The great majority of those species are widespread in the Greater Caribbean, with only
Two species that are commonly found on reefs nearby and more widely within the greater Caribbean were conspicuously absent/rare at Cayo Arcas:
Future, comprehensive faunal surveys should be made of the reef fish faunas not only of Cayo Arcas but also other, more poorly known emergent reefs and submerged banks near the outer edges of Campeche Bank to assess their reef fish faunas, to gain a better understanding of the biogeography of their fishes, and their importance for conservation, as well as assessing them as natural biogeographical experiments. Those surveys should also involve genetic analyses to determine the extent to which the regional fauna and faunas of individual reefs include cryptic endemic species.
Thanks to Quetzalli Hernandez, whose leadership of the Cayo Arcas expedition of August 2016 greatly facilitated work there, and to essential support by the captain (Héctor Agustin Torres Murillo) and crew of the Buque de Investigación Oceanográfico Arm “Hondo” (BI-06), Secretaria de Marina, Estados Unidos Mexicanos. The 2016 expedition was financed by grants to NS from the Harte Institute (Biodiversity of the southern Gulf of Mexico) and CONABIO (NE018; Actualización del conocimiento de la diversidad de especies de invertebrados marinos bentónicos de aguas someras (< 50m) del Sur del Golfo de México. Fieldwork in 2013 was funded by SEP-CONACyt grants 69747 to HP-E and 108083 to ENL.