  The land crab Cardisoma guanhumi Latreille, 1828 is harvested in several
countries in Latin America, and a critically endangered species. This is the
first study to conduct bootstrapped tagging analysis (BTA) together with
bootstrapped length-frequency analyses (BLFA). Crabs were sampled monthly in a
mangrove patch at Itamaraca Island (Brazil), over 12 months, and marked with
PIT tags. Both methods (BTA and BLFA) indicate very slow growth and Linf far
above Lmax. BTA estimates were K = 0.12 y-1 (95% CI: 0.024 to 0.26 y-1), Linf =
118 mm (95% CI: 81 to 363 mm), Phi' = 1.23 log10(cm y-1) (95% CI: 0.86 to 1.36
log10(cm y-1)). Seasonality in growth was significant (p = 0.006, 95% CI for C:
0.15 to 0.93, median: C = 0.56). Pairs of K and Linf always followed narrow
Phi' isopleths. Total mortality was Z = 2.18 y-1 (95% CI = 1.7 to 4.5 y-1).
Slow growth and a very high Z/K ratio highlight the need for protective
measures. BTA results were 2.2 to 3 times more precise than BLFA. Traditional
length-based methods produced grossly biased results, indicating the urgent
need for new, robust approaches and a critical reevaluation of long-standing
methods and paradigms.
