First record of Batrachoides surinamensis ( Bloch & Schneider , 1801 ) and Canthidermis maculata ( Bloch , 1786 ) ( Pisces : Teleostei ) from Rio Grande do Norte , northeastern coast of Brazil

A new occurrence each of Batrachoides surinam­ ensis and Canthidermis maculata is reported in the northeastern coast of Brazil. This report adds to the known records for both species and increases the regional marine fish richness to 461 species. Following these records, 1.6 tons of C. maculata were landed from May 2016 to January 2017, representing more than 1,500 individuals caught monthly. While it sheds light on the importance of C. maculata, the economic and social role of B. surinamensis remains unknown. Likewise, their conservation status is currently uncertain and further investigation is warranted.

The fish family Batrachoididae is represented in Brazil by 6 genera and 13 species (Menezes et al. 2003), including Pacuma Toadfish, Batrachoides surinamensis (Bloch & Schneider, 1801).Batrachoides surinamensis is typically found in shallow brackish waters of estuarine environments (Léopold 2004).It has been recorded from Central America (Honduras) to Brazil (Bahia state) (Collette & Russo 1981;Carvalho-Filho 1999).The Rough Triggerfish, Canthidermis maculata (Bloch, 1786), is a member of the family Balistidae, which is represented in Brazil by 4 genera and 6 species (Menezes et al. 2003).Canthidermis maculata is an oceanic pelagic fish that has a circumglobal distribution in tropical and temperate seas.In the Western Atlantic, it occurs from New Jersey (USA) to Argentina (McEachran & Fechhelm 2005).Here, is reported the first record of both species on the coast of Rio Grande do Norte state (RN), northeastern Brazil (Fig. 1).
On 10 October 2015, 1 specimen of B. surinamensis (Fig. tic scheme proposed by Collette & Russo (1981).The main morphometric and meristic data (Table 1) observed agree with the description reported by these authors.On 19 May 2016, 2 specimens of C. maculata (Fig. 3) were caught on the surface by an artisanal fishing boat with dip nets, at Urca da Conceição (04°55ʹ S, 036°05ʹ W), a 20 m deep reef located at 9 nautical miles northwest of the city of Caiçara do Norte, northern coast of RN.The individuals were identified as C. maculata based on characters reported by Moore (1967) and McEachran & Fechhelm (2005), with main morphometric and meristic data (Table 2) in agreement with the criteria given by these authors.All specimens were fixed in 10% formalin, transferred to 70% ethanol and deposited in the Fish Collection of Laboratory of Fisheries Biology at Federal University of Rio Grande do Norte (B. surinamensis, LABIPE 1051, and C. maculata, LABIPE 1101and 1102).All morphometric data were taken using digital calipers with 1 mm precision and total weight was measured to the nearest 1 g using an electronic weighing balance.
The specimen of B. surinamensis was identified based on following distinctive characteristics: body with embedded small scales with a scaled area on head extending to middle of orbit and opercular spine, opercular and subopercular bones with 2 spines, 3 dorsal fin spines, and supraorbital and interorbital region smooth, without any filament.
The specimens of C. maculata were identified based on following main characteristics: absence of flexible tympanum, mouth terminal, 23 or 24 dorsal fin rays, 20 or 21 anal fin rays, gray-to-brown body, lighter ventrally and with some light spots on the sides and ventral surface of the body.
Batrachoides surinamensis is reported in literature as ranging in Brazil from Amapá to Bahia states and it was recently recorded in Amapá (Maia et al. 2016)    the conservation status may not represent historical declines.
In Rio Grande do Norte, fishing activities are considerably unregulated, unreported, and to some extent also illegal (Ross et al. 2015;Damasio et al. 2015;Bevilacqua et al. 2016).Some fisheries and target species are poorly assessed or not assessed at all, and the presence, abundance, and availability for fisheries of some species might be misreported.Therefore, their actual conservation status might have been unknown to researchers, fisheries managers, and younger fishers before such species were first assessed.This seems to be the case, for example, for C. maculata; in data collected from fishers (see Damasio et al. 2015), elderly fishers reported high catches of triggerfishes prior to 2003 and the complete disappearance of current landings.However, fishers used just common names (cangulo) and grouped together several species such as Bali stes vetula, B. capriscus, and Cantherhines macrocerus.Thus, poor historical data on species' occurrence do not allow for the precise identification of species.The implication of this lack of historical information is the assumption that C. maculata is under Least Concern for the fishery, economy, and conservation.In general, the major interest in research has been on the commercially important fishes, resulting in less research effort on non-commercially important species such as C. maculata (Abdussamad et al. 2009).Nonetheless, there is increasing demand and global exploitation of Rough Triggerfish for human consumption, export, and for aquarium purposes (Sahayaki et al. 2014).Consequently, this species has economic and social importance for communities around the Indian, Atlantic, and Pacific oceans, enhancing Bahia, the recognized southern limit of the range for this species, the only record found was the MCZ Thayer Expedition specimen from Salvador city (Collette & Russo 1981).Following the new record described here, Sergipe state currently figures as the only gap in this species' distribution along its expected range.Most likely this gap is a consequence of poor sampling, mainly in estuarine areas.An increased sampling effort in brackish waters of estuarine environments, where the species is typically found, would probably fill this gap.
Although the distribution of Canthidermis maculata is expected to extend along the entire Brazilian coast, this species was only recorded in Bahia (Moraes et al. 2008) and Santa Catarina states (Hostim-Silva et al. 2002).In addition, Murray (1902) reported the occurrence of this species (as Balistes maculatus) around Trindade Island, located 1160 km off the central coast of Brazil.Herein is reported the third confirmed record of C. maculata for the Brazilian coast.
Recently, the coastal fish species of Rio Grande do Norte was revised totaling 459 species, including 4 species of batrachoidids and 5 balistids (Garcia Jr. et al. 2015).Therefore, the new occurrences reported here enlarge the distributions for both B. surinamensis and C. maculata and increase the number of species in this state to 461 species.
Even though both species are now listed as Least Concern by the International Union for Conservation of Nature (Collette 2010;Leis 2015) and by the Brazilian Red List of Endangered Species/BRL-EndS (Decree no.445; MMA 2014),  the accumulation of biological and ecological information (Sahayaki et al. 2014;Lezama-Ochoa et al. 2016).Following this trend, after this first record of C. maculata, during 5 months of ongoing landing records, we recorded the landing of 1.6 tons of this species at the main port of RN state (230 km from the record reported herein) (Fig. 4).On average, this represents 230 kg of C. maculata landed monthly and roughly more than 1500 individuals caught per month in the northeastern coast of Brazil.Therefore, we are optimistic that the new record reported here and the record of these landings will boost interest in better understanding the importance of C. maculata in the Western Atlantic.However, while the records presented here sheds light on the importance of C. maculata, the economic and social role of B. surinamensis remains unknown.Likewise, their conservation status is currently unsure and warrants further investigation.

LITERATURE CITED
Figure 1. A. Geographical localization of the Rio Grande do Norte state (RN) in the South America.B. North coast of RN.Red star indicates the site where Batrachoides surinamensis was caught.Black star indicates the site where Canthidermis maculata was caught.

Figure 4 .
Figure 4. Canthidermis maculata landed on 2 March 2017 in the main port of Rio Grande do Norte state.The photo shows roughly 100 individuals.Total landings recorded in this date reached 600 kg of the species.