These data provide information about population growth, which is useful in monitoring and for predicting the expansion of this non-native species, as well as giving
an opportunity to compare the different populations of the same species inhabiting different geographical locations. Individuals of the North American Harris mud crab were collected Selleckchem CH5424802 between 2006 and 2010 from the Gulf of Gdańsk at randomly chosen sampling points (Hegele-Drywa & Normant 2014) (Figure 1). Samples were taken with a bottom dredge (33 × 66 cm, mesh size 0.5 × 0.5 cm) from the r/v ‘Oceanograf 2’, at 129 randomly chosen sampling points located at depths from 5 to 60 m from 2006 to 2010 (Table 1). The single dredging time was 5 min at a vessel speed of 1.5 knots. CPUE was estimated for four people during five hours. Specimens were hand-sorted from the sampled material and frozen (–20°C) directly after collection. In the laboratory, the crabs were sexed on the basis of abdominal structure and pleopod
Ibrutinib in vitro shape (De Man 1892). Furthermore, during examination crabs were analysed for evidence of the external form of the rhizocephalan Loxothylacus panopaei ( Gissler 1884). Specimens with a carapace width < 4.4 mm were classified as juveniles ( Turoboyski 1973), and females with eggs attached to the pleopods were classified as ovigerous. Carapace width (CW) and length (CL) and major chela length (CHL) and height (CHH) were measured (± 0.01 mm) with slide calipers. Moreover, while these Sclareol measurements were being made, right vs. left claw dominance was determined. Growth ratios for the independent variable (CW) and dependent variables (CL, CHL) were determined by using the logarithmic transformation (log y = log a + b log x) and the function y = axb, where x is the independent variable (CW), y is the dependent variable, a is the intercept (value of y when x = 0), and b the slope
of the regression line. The value of b indicates the growth patterns of the variables: b = 1 (isometry), b < 1 (negative allometry), b > 1 (positive allometry) (Hartnoll 1982). The statistical significance of b was tested using Student’s t-test. After surface water had been blotted off the individual animals with soft tissue paper, their wet weight was measured with an accuracy of ± 0.001 g. They were then dried at 55°C to constant weight and reweighed. The crabs were divided into 2 mm carapace width classes. Some of the crabs were incomplete (e.g. with a missing walking leg or chela); therefore fewer specimens were used in a particular analysis (e.g. the carapace width-wet weight relationship) than the total number of specimens collected. Fulton’s condition factor (K) was calculated for each individual according to the equation given by Nash et al. (2006): K=100×WW/bCW,K=100×WW/CWb,where WW is the wet weight of an individual [g], CW is the carapace width [mm] and b is the regression coefficient of the carapace width-wet weight relationship. Analyses were carried out using the STATISTICA 8.0 PL program.