Modified Delury depletion model applied to spiny lobster, Panulirus argus (Latreille, 1804) stock, in the southwest of the Cuban Shelf

Spiny lobster recruitment and stock size were estimated in the Gulf of Batabanó (SW Cuban shelf), on a monthly basis for the period 1983–2003 using a modified Delury model. Both recruitment and stock size follow a decreasing trend over the last 10–15 years. Additionally, monthly values of fishing mortality (F) and catchability (q) were computed for each fishing season, taking into account the principal fishing gears used (artificial shelters or traps joined by strips of nets). Highest F-values were usually obtained at the beginning of the fishing season (June), with the exception of the years 1983, 1988 and 1989 when highest values corresponded to the massive autumnal migration months (October–November). The average catchability for the first month of the fishing season (June) was slightly higher than the one for migration months (q = 1.14 × 10−5 compared to q = 1.11 × 10−5, respectively), while average catchability for the remaining months was significantly lower (q = 0.72 × 10−5). Mean annual exploitation rates did not exceed 50%, while some months had values >60%. The annual series obtained for recruitment, stock size and fishing mortality were compared with ADAPT tuning VPA series obtained by other authors and proved to be consistent.