Length-weight relationships (LWR) were described for 53 species of shallow-water fish caught with bottom trawls in a depth range between 7.3 and 108.1m during September 2013 in the Colombian Caribbean Sea (fishing area 31 of the FAO). A linear regression was performed using the logarithmically transformed data to calculate a and b coefficients and their 95 confidence interval of the LWR for 53 fish species corresponding to 28 families and 44 genera. Six fish species showed a maximum total length greater than that reported in FishBase: Astrapogon alutus (102.00mm), Eucinostomus harengulus (162.00mm), Haemulopsis corvinaeformis (293.00mm), Cyclopsetta chittendeni (390.00mm), Etropus crossotus (224.00mm), and Bairdiella ronchus (415.00mm). A total of 24 species (45.3) exhibited isometric growth, 21 species (39.6) negative allometric, and 8 species (15.1) positive allometric. This study shows the first estimates of LWR for 25 species of shallow-water fish in the Colombian Caribbean Sea. We found interdependence of growth parameters as a function of fish body shape. The analysis of the relative condition factor indicated that 21 fish species (39.6) showed poor growth conditions. The results obtained from this study contribute to fill information gaps on shallow-water fish populations and also help fisheries scientists in future population assessment studies in the Colombian Caribbean Sea.

Scientific knowledge-based fishery management is essential to ensure the sustainability of marine resources, particularly in regions where fisheries are data-limited. This study assessed the stock status of six shallow-water demersal fish species (Bagre marinus, Cathorops mapale, Diapterus rhombeus, Eucinostomus argenteus, Haemulopsis corvinaeformis, and Lutjanus synagris) in the Colombian Caribbean Sea using three complementary length-based models: length-based indicators (LBIs), length-based spawning potential ratio (LBSPR), and the Length-Based Bayesian Biomass estimator (LBB). The integrated results demonstrated that five species (C. mapale, D. rhombeus, E. argenteus, H. corvinaeformis, and L. synagris) are currently overexploited (F/M > 1 and B/B_MSY < 1), while B. marinus is experiencing overfishing (F/M > 1 and B/B_MSY > 1), with a high risk of surpassing its maximum sustainable yield. These outcomes confirm that demersal fish populations in the Colombian Caribbean are being exploited beyond sustainable biological limits. With the aim of promoting stock recovery and long-term sustainability, this study recommends the implementation of recently evaluated management measures focused on (i) the implementation and enforcement of Bycatch Reduction Devices (BRDs); (ii) the regulation and monitoring of trawl net mesh sizes to improve selectivity patterns; (iii) the establishment of spatial and temporal closures in critical spawning areas for demersal fish species; and (iv) the strengthening of fishery monitoring and data collection systems. The findings provide critical baseline information and a methodological framework to support evidence-based fishery management and conservation strategies in tropical multispecies fisheries under data-limited conditions.

The deep-sea Caribbean lobster (Metanephrops binghami) and the Norway lobster (Nephrops norvegicus) are Nephropidae species of high commercial interest. Although the first one still remains unexploited, the second is overexploited in the Mediterranean Sea. For effective fisheries management, size at sexual maturity is an essential indicator to protect immature individuals from exploitation. The estimation of this indicator can, however, be biased due to the difficulty of differentiating juveniles from adults by their size structure due to the natural process of molting. This study aims to estimate the size at sexual maturity of M. binghami and N. norvegicus females by comparing the effectiveness of the morphometric method versus the macroscopic evaluation of gonad maturity. Samples of M. binghami were collected from the Colombian Caribbean Sea in August and December 2009, March and May 2010, and August 2020 to May 2021. Samples of N. norvegicus were collected from the northwestern Mediterranean Sea from 2019 to 2022. Similar sizes at sexual maturity were found for M. binghami between the morphometric approach (ranging from 28.6 to 33.9 mm cephalothorax length, CL) and the gonadal staging approach (31.4 mm CL). Conversely, for N. norvegicus, the morphometric approach yielded higher measurements (between 27.2 and 30.4 mm CL) than the gonadal approach (26.0 mm CL). This discrepancy might stem from the intense fishing overexploitation conditions of N. norvergicus, leading to a physiological adaptation that enables earlier gonadal maturation at faster rates than morphometric adaptation. Further research is required to elucidate these discrepancies and the effect of overexploitation on physiological (i.e., mature gonads) and functional maturity (i.e., capacity to brood eggs at a larger size).