Size at the maturity of sea cucumber Holothuria scabra. Is it an overfishing sign in Wallacea Region?

As the largest trepang producer in the world, Indonesian trepang product still depends on wild catches. This wild catch could cause overfishing. In many fishing areas, sea cucumber populations have decreased to the point where they can be considered as a rare species. The wild catch could lead to a negative impact on size at maturity. Biologically, there are two types of reproductive strategies at marine organisms, i.e. 'r-selection' and 'K-selection'. The 'r-selection' type was found in organisms that are dominantly controlled by their environmental factors and tend to reach physical maturation faster, while the 'K-selection' type was controlled more by biological factors, such as the presence of competitors. This study aims to analyze the size at the maturity of sea cucumber Holothuria scabra for different years to find out if the size at maturity can be used as a reference of the overfishing sign in the Wallacea region. The H. scabra or sandfishes were taken from the catches of fishermen at the Sub-district Liukang Tupabbiring Utara, Pangkep Regency, South Sulawesi, Indonesia. The Liukang Tupabbiring area is in the Spermonde Islands region, which is part of the Wallace line trajectory. Samplings were carried out for four years, from 2016 to 2019. The parameters measured were a total length (TL), total weight (TW), and gutted body weight (BW). The parameters observed were the color and stage of the gonad. The sizes at maturities were defined as the percentage of sexually mature, which were the sandfish with gonad stages of III, IV, and V. The study reveals that the size at maturity of sandfish was reached at a smaller size than previously reported. Biologically, smaller sizes at maturity could be a sign that sandfish has overfishing. As one organism whose biological organ structure was still primitive, Sea cucumber probably maintains the continuity of its generation by adapting reproductive strategy "r-selection type".