The sea cucumber Isostichopus badionotus has been overfished in the Yucatan Peninsula. Due to this, population restoration actions have been proposed, such as the translocation of wild individuals or the release of captive-bred juveniles in reserve or non-fishing areas. To determine the optimal size of the reserve areas, it is necessary to know the potential dispersal of individuals throughout their life cycle, which is generally based on studies of the movement patterns and short-term dispersal rates. The objective of this work was to estimate the movement patterns and dispersal rates of I. badionotus to provide key knowledge for the design of protection zones for the species.
A set of experiments were carried out under semi-controlled conditions, in external ponds with 50% sun protection and natural fluctuation of temperature and solar radiation. Fifty-five organisms classified as small, medium and large were used to determine the pattern and magnitude of movement in daily cycles, as well as its relationship with temperature and solar radiation. The preference for the use of colonized and non-colonized artificial refuges was also evaluated. The movement rates were obtained using a camera located in a zenithal position above the experimental tank. Differences in displacement were identified between large and small cucumbers (ANOVA, p = 0.0252, Tukey HSD). The average daily movement for the size class was: 518 cm for small, 615 cm for medium sizes and 688 cm for large sizes (Table 1). The displacement pattern was characterized by a very low displacement in the mornings (07:00 to 14:00), a maximum in the afternoon (16:00 to 22:00) and intermediate at night (23:00 to 5:00). A positive linear relationship was determined between organism size (estimated length: eL) and total daily displacement (D) (D = 2.88 eL + 22.27 cm). Positive correlations (Spearman: rs) were obtained between the displacement of large and medium organisms with temperature (rs: 0.48, 0.89) while, negative rs values were observed between displacement and light intensity in small organisms (rs: - 0.44, - 0.74). Higher percentage of use of refuge by small organisms (53% of the daily time) and greater affinity for colonized refuges (80% of refuge use) were observed. Medium and large organisms did not presented shelter preferences (<20% of the daily time). This demonstrates the importance of shelters. Daily movements found in this work are similar to other sea cucumbers species, being most active in the afternoon and at night, and provides specific data for long dispersion models for I. badionotus.