During biannual sampling, shrimp were identified by
species and counted, and their reproductive status was
recorded (gravid or/and mature, non-gravid). Carapace
length (CL) and presence of coloured tags were also
recorded on site. Shrimp were measured from the tip of
the rostrum to the post-median edge of the cephalothorax
to the nearest 0.01 mm with a dial calliper. The CL
measurements were used instead of the post-orbital
length due to the absence from the stream of fish that
induce variable enlargement of the rostrum in the
shrimp (Covich et al., 2009; Ocasio-Torres et al., 2014,
2015). All shrimp were returned to their respective
pool. Identifications were based on Chace & Hobbs
(1969). If storm flows occurred during the sampling,
traps were removed, shrimp released and the sampling
rescheduled for the next day that had base-flow conditions.
Physical parameters measured for the pools
included three width measurements, five random
depths, maximum water depth, and pool length. Pool
area and volume were derived from these data. Shrimp
densities (shrimp m
2) were determined from each pool
during sampling. Values for precipitation, together with
air and water temperature, were obtained from the
long-term data sets of the LUQ-LTER. We calculated
growth rate (GR) as: Growth Rate (mm year
1) = (final
length – initial length)*(time)
1. All calculations of
length were based on CL.
During biannual sampling, shrimp were identified byspecies and counted, and their reproductive status wasrecorded (gravid or/and mature, non-gravid). Carapacelength (CL) and presence of coloured tags were alsorecorded on site. Shrimp were measured from the tip ofthe rostrum to the post-median edge of the cephalothoraxto the nearest 0.01 mm with a dial calliper. The CLmeasurements were used instead of the post-orbitallength due to the absence from the stream of fish thatinduce variable enlargement of the rostrum in theshrimp (Covich et al., 2009; Ocasio-Torres et al., 2014,2015). All shrimp were returned to their respectivepool. Identifications were based on Chace & Hobbs(1969). If storm flows occurred during the sampling,traps were removed, shrimp released and the samplingrescheduled for the next day that had base-flow conditions.Physical parameters measured for the poolsincluded three width measurements, five randomdepths, maximum water depth, and pool length. Poolarea and volume were derived from these data. Shrimpdensities (shrimp m2) were determined from each poolduring sampling. Values for precipitation, together withair and water temperature, were obtained from thelong-term data sets of the LUQ-LTER. We calculatedgrowth rate (GR) as: Growth Rate (mm year1) = (finallength – initial length)*(time)1. All calculations oflength were based on CL.
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