Length-weight relationships for freshwater fish species from humid forest enclaves at the Brazilian semiarid

Abstract

We report the length- weight relationships (LWR) for 11 fish species inhabiting head-water streams in the Araripe and Ibiapaba plateaus, Brazilian semiarid. Values of r2, aand b ranged respectively from .953 to .998, 0.010 to 0.043 and 2.81 to 3.69. Our reports on LWR are pioneer in humid forest enclaves at the Caatinga biome. Such enclaves of forest can be a checkpoint to climate change, but are under strong human pressure and remain under low investigation.1 | INTRODUCTIONBasic data reporting the length- weight relationships (LWR) are unavailable for headwater stream fishes in the Brazilian semiarid, despite the high endemism in the Caatinga biome (Rodrigues- Filho et al., 2016; Rosa, Menezes, Britski, Costa, & Groth, 2003). While this region is suffering strong human pressure through impoundment and introduction of non- natives fish species (Rosa et al., 2003), LWR data enable the assessment of climate change effects and stimulates fish-eries research, taken together ecology, evolution, conservation and management (Froese & Pauly, 1998; Nahum, Castello, & Rosenthal, 2009; Vergés et al., 2016). LWR also reflects suitable conditions to fish populations in time and space and enables a comparison of sexual maturity and feeding conditions (Chaves, Sánchez- Botero, Garcez, & Reis, 2013; Wootton, 1998).An adequate description of traits (including LWRs) indeed remains incipient in humid forest enclaves at the Brazilian semiarid, if conside-ring non- target fish species inhabiting humid forest enclaves. This is the report on LWRs considering more than a group of target fish species in riverine basins in the Caatinga biome (Nascimento et al., 2011; Novaes, Costa, Mourato, & Peretti, 2014) and the first report in humid forest enclaves in the Araripe and Ibiapaba plateaus, Ceará State. Therefore, we are also contributing to the toolbox employed in the conservation of the Neotropical fish biodiversity, adding to their life history, beyond the taxonomic variation in riverine environments (Rosa & Groth, 2004).2 | MATERIALS AND METHODSWe sampled the fish fauna at humid forest enclaves into tablelands of Araripe (AR) and Ibiapaba (IB), located in the Northeastern Brazil in the coordinates limits 7°48′19′′S 39°20′16′′W – 7°28′33′′S 39°44′27′′W at the AR and 3°40′17′′S 40°53′44′′W – 3°52′00′′S 40°51′53′′W at the IB. IB plateau ranges from 900 m to 1,000 m of elevation (Claudino-Sales & Lira, 2011), mean rainfall of 1,000 mm in the rainy