Review of the occurrence and distribution of the basking shark ( Cetorhinus maximus) in Chilean waters

Abstract

The occurrence of Cetorhinus maximus in Chilean waters is reviewed based upon biological, geographical and temporal data obtained from 30 specimens observed between 1905 and 2009. These records were established from 27840 ′ S (Punta de Cachos, Bahía Salado) to 55845 ′ S (Cabo de Hornos). Both males and females were incidentally caught in artisanal gill-net fisheries. The records suggest a segregation of C. maximus by groups of sex -size. Temporal data suggests that C. maximus primarily occur in Chilean coastal waters during spring and summer.

Not all fish are equal: functional biodiversity of cartilaginous fishes (Elasmobranchii and Holocephali) in Chile

“…Use and misuse of common names also occurs; for example, in official landings, records of all hound sharks are considered to be the speckled smooth-hound Mustelus mento Cope 1877, despite the fact that four other hound shark species are landed under this category. With the exception of Z. chilensis, the same situation is observed when skates are landed and recorded generically as skate (Lamilla, 2005;Lamilla et al, 2010). Similarly, in the pelagic longline fishery both, shortfin and longfin mako sharks (I. oxyrinchus and I. paucus) respectively, are combined under a single mako shark landing category (Bustamante et al, 2009).…”

“…The biodiversity of cartilaginous fishes is here increased to 106 by the addition of 10 species to the most recent review (96 species; Lamilla & Bustamante, 2005). This significant increase to the records of the national biodiversity reflects an increase in marine research since the implementation of the National Plan of Action to promote conservation and management of sharks and their relatives (Lamilla et al, 2010). Chile has a relatively impoverished cartilaginous fish fauna when compared with the global species inventory (Table IV).…”

“…Despite the increased research effort that usually accompanies fisheries exploitation, the basic biology and taxonomy of cartilaginous fishes in Chile is still poorly known. Elasmobranchs and holocephalans are commonly caught as target and by-catch in several trawl, coastal gillnets and longline fisheries along the Chilean coast, but capture records (by-catch and discard) are rarely reported, with the exception of target species (Lamilla et al, 2010).…”

“…Non-resident migrant species, single-specimen descriptions, documented anecdotal observations and incidental observations in remote locations collectively result in the group of confirmed species, but of rare occurrence. This group includes those species for which there is taxonomic uncertainty and single-specimen reports ( (Lamilla et al, 2010). Particularly, interesting cases are Chilean round stingray Urobatis marmoratus (Philippi 1892) and T. philippii, two species with no known holotype (Pequeño, 1989), and Chilean round ray Urotrygon chilensis (Günther 1872), a relatively abundant coastal ray of the central-east Pacific Ocean with a distribution from Mexico to Peru, that was described from Chile (no location data, unique holotype) by Günther (1872), but has not been observed in the region since that time.…”

Biology, Taxonomy and Distribution of south-east Pacific Cartilaginous Fishes

“…The latter, usually report the presence of these stranded animals, i.e., the mass stranding of devil rays Mobula mobular (Couturier et al, 2013) or pygmy killer whales Feresa attenuate (Mignucci-Giannoni et al, 2000); and have even managed to describe new species (i.e., the Perrin's beaked whale Mesoplodon perrini, Dalebout et al, 2002). In other instances, these records serve to rebuild seasonal migrations (i.e., the basking shark Cetorhinus maximus, Hernández et al, 2010). These examples illustrate the potential for gaining knowledge about the occurrence and distributions of cartilaginous fishes through interaction between scientists and the general public, be they fishers, divers, snorkelers or just someone walking along a beach and finding something odd and bringing it to the attention of experts.…”