No-take reserves (NTRs) are marine protected areas where fishing is prohibited. They contribute to the restoration of marine habitats and communities impacted by fishing, and can provide spillover benefits to neighbouring areas. This study investigates the restoration effectiveness of the 10 km2 deep-sea NTR "Cigala de Rosas-Palamos" (350-475 m depth). It focuses on the benthic megafauna community structure and size spectra associated with the fishery-targeted stock of Norway lobster (Nephrops norvegicus) in the Northwestern Mediterranean Sea. Experimental demersal trawl surveys were conducted before the NTR's implementation in 2017, and four years later in 2021, both outside and inside the NTR. All individuals were classified and sized, to generate ecological indicators of groups similarity, diversity, density, biomass, and size spectra. All indicators improved four years after fishing halted inside the NTR. A new normalised aggregated size spectrum was developed for the full community to address differences in species groups catchabilities, which revealed an overall worsening (steepening) community size structure outside of the NTR and an improvement (shallowing) inside it. The crustacean community, the main local fishery target, had a likelihood-based size spectrum exponent b of-1.28 in 2017. By 2021 it became steeper (-1.94) outside the NTR, reflecting the loss of larger individuals under continued fishing pressure, whereas inside the NTR it became slightly shallower (-1.26), consistent with a recovery of the size structure upon protection. These findings suggest the broad recovery of demersal communities beyond commercially targeted species, highlighting the effectiveness of NTRs as tools for deep-sea ecosystems conservation and restoration.

The distribution of zooplankton biomass in the upwelling system of La Guajira (Caribbean Sea), was evaluated using more than 800 linear km of acoustic data obtained from two samplings conducted in 2018 during a period of weak (May) and intense (December) upwelling. Modeling of the spatial variability and interpolation of zooplankton acoustic biomass was performed using a geostatistical method and its relationship with environmental variables through generalized additive models. It was found that the spatial distribution of zooplankton acoustic biomass was different in the two periods evaluated. In May it was concentrated on the edge of the continental shelf and in December it was associated with upwelling foci or areas with high fluvial inputs from the Magdalena River (Gulf of Salamanca). In the weak upwelling period, zooplankton biomass was higher and was associated with high dissolved oxygen concentrations and low chlorophyll-a levels. The seasonal variability of zooplankton biomass does not show a linear relationship with upwelling intensity, probably as a consequence of air-ocean-river interaction processes affecting the region.

The accumulation of marine litter in the oceans has generated increasing concern within the scientific community due to its significant impact on ecosystems. Most research has focused on coastal areas and surface waters, leaving a gap in knowledge regarding deep-sea environments. This study aimed to assess the presence, composition, and distribution of marine litter in deep waters of the Colombian Caribbean. Sampling was conducted using a trawl net at depths of up to 600 m in the marine area between Santa Marta and Palomino river. The classification of marine litter was conducted using the OSPAR monitoring guide, complemented by a visual assessment based on criteria such as color, shape, and other distinctive characteristics. A total of 46 marine litter items were collected, 93.5 % of which were plastics, followed by wood (4.3 %) and metals (2.2 %). Materials such as paper, glass, and textiles were not found in significant quantities. The highest concentration of litter was detected in areas near Tayrona National Park, with plastic debris present at 10 out of the 11 total stations where marine litter was recorded. Among the plastics collected, bags, bottles and containers predominated, representing 90.1 % of the total weight of the waste collected (405.89 g). These findings highlight the urgent need to address plastic pollution through policies and actions aimed at reducing its production, promoting recycling, and preventing its entry into the marine environment.

ABSTRACTThe pink shrimp (Penaeus notialis) constitutes an important commercial fishery in the Colombian Caribbean. However, due to the lack of biological data and fisheries management information led to the overexploitation and collapse of the shrimp fishery. Despite the economic and commercial importance of this fishery in the Colombian Caribbean, no studies have been carried out on the growth and mortality of pink shrimp. The objective of the present study was to estimate for the first time robust von Bertalanffy growth parameters, mortality rates with empirical formulae and the length‐converted catch curve of the commercial pink shrimp (P. notialis) in the Colombian Caribbean. The samples were collected between June 2012 and May 2013, between Cartagena and the Gulf of Urabá. The parameters of the growth were estimated using the electronic Length frequency analysis. We calculated the natural mortality (M) with the K and L∞ parameters. A total of 5199 pink shrimp were collected. The estimates of growth parameters for P. notialis showed higher L∞ (females: 171.91 mm; males: 135.37 mm) and W∞ in females (44.74 g) than in males (19.44 g). The growth coefficient (K) was 0.74 in females and 1.19 in males. The ta estimated for females was −0.12 and for males −0.04. The maximum age (tmax) of this species was 3.91 year for female and 2.47 year for male. The natural mortality rate (M) for female was (0.61 year−1) and male (0.93 year−1).

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).

Se evaluaron los hábitos alimentarios del bonito Euthynnus alletteratus y la albacora Thunnus alalunga a partir del análisis de los contenidos de 85 estómagos (50 de bonito y 35 de albacora) recolectados entre marzo de 2018 y abril de 2019. Se realizó un análisis cualitativo y cuantitativo de las presas encontradas en dichos estómagos, así como del espectro trófico entre especies y temporadas climáticas. La información climática se obtuvo a través de imágenes satelitales, analizando variables como la temperatura superficial del mar, la salinidad y los vientos. En términos de abundancia, las presas más representativas fueron el pez Sardinella aurita (42.48 %) y restos de Teleostei (27.45 %) para E. alletteratus, y larvas megalopa (56.89 %) y restos de Teleostei (10.26 %) para T. alalunga. El índice de importancia relativa indica, como presas principales, a restos de Teleostei (IRI = 1460.65) y Sardinella aurita (IRI = 1179.70) para E. alletteratus, y a larvas megalopa (IRI = 1367.19) y restos de Teleostei (IRI = 840.94) para T. alalunga. Estos grandes depredadores pelágicos fueron catalogadoscomo generalistas, con baja diversidad de presas en el contenido estomacal, y no se observó solapamiento trófico entre las dos especies.

Composition, size distribution, structure, and function of deep-sea marine communities must be understood before they are impacted by anthropogenic effects. The deep-sea ecosystem of the Colombian Caribbean Sea is unexploited with no fishing activity ever registered. We quantified the current state of the marine community using body size distribution (size-spectra), size-based indicators, minimum length (L-MIN), maximum length (L-MAX), average length (Lmean), standard deviation of length (L-SD), 10th and 90th percentiles of the length distribution, Shannon-Wiener diversity (H '), and Pielou's evenness (J ') to generate a baseline of potential ecological indicators that contribute to management and conservation of the Colombian bento-demersal community of deep-sea marine ecosystem. Sampling was in the Colombian Caribbean Sea at 58 stations during four samplings in August and December 2009, 21 stations in March and May 2010, and 45 stations from August to December 2020, using the swept area method, at depths of 200-550 m. Catches included >50% families and species of fish, followed by 27 families (30%) and 33 and species (37%) of crustaceans. Chondrichthyes included 14% families and 9-11% species. Cephalopods included 2-3% families and 1-4% species. Size-spectra analysis confirmed expected values for unexploited communities in three sampling years for teleostei, crustacea, and whole community.

Length-weight relationships (LWR) and relative condition factor were described for species of deep-water crustaceans caught with bottom trawls in a depth range between 150 and 535 m during August and December of 2009, and March and May of 2010 in the Colombian Caribbean Sea. A linear regression was performed using the logarithmically transformed data to calculate the a and b coefficients of the LWR for 22 crustacean species corresponding to 13 families and 19 genera and three types of crustaceans (shrimp, crab, lobster). Six crustacean species showed a maximum total length greater than that reported in SeaLifeBase: Garymunida longipes (77.00 mm), Eunephrops bairdii (220.00 mm), Metanephrops binghami (197.46 mm), Penaeopsis serrata (149.00 mm), Polycheles typhlops (196.27 mm) and Pleoticus robustus (240.00 mm). A total of 11 species (50.0%) exhibited isometric growth, five species (22.7%) negative allometric and six species (27.3%) positive allometric. This study shows the first estimates of LWR for 12 species of deep-water crustaceans in the Colombian Caribbean Sea. We demonstrate for the first time that the growth parameters (intercept and slope) of the LWR varying significantly as a function of the body shape of crabs, lobsters and shrimps in deep-water crustaceans.

Yellow squat lobster fishery is one of the most important extractive activities in the central zone of Chile that occurs between 100 and 300 m deep. One of the difficulties in the management of the fishery is the high variability of the indices of abundance, which depends on the spatial distribution of the resource, among other things. Given the limited knowledge of spatial distribution patterns and spatiotemporal changes in yellow squat lobster density and biomass, the information collected during trawl survey assessments between 1999 and 2019 in central Chile was analyzed. Using the criteria of presence, persistence, distance, and discontinuity, 23 areas of aggregation between 26 degrees 42 ' and 36 degrees 54 ' S were identified and used to model the catch per unit area by a generalized additive models. The model explained 21.4% of the deviance and allowed us to show the population growth from 2001 onward between the regions of Valpara & iacute;so and Biob & iacute;o, which was consistent with the extractive closure implemented by the managers from 32 degrees 10'S to the south. Most of the biomass of Cervimunida johni (similar to 75% of the biomass) was located in the Coquimbo, Puerto Oscuro, La Ligua, Valpara & iacute;so, Pichilemu, and Biob & iacute;o aggregations, corresponding to 57% of the total surface where the resources were distributed. The present work provides information on the places that have been persistently occupied by Cervimunida johni, suggesting to managers an evaluation of the spatial limits that are currently being used in the surveys and their influence on the performance of the population evaluation model.

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 108.1 m 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 (102.00 mm), Eucinostomus harengulus (162.00 mm), Haemulopsis corvinaeformis (293.00 mm), Cyclopsetta chittendeni (390.00 mm), Etropus crossotus (224.00 mm), and Bairdiella ronchus (415.00 mm). 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.

The spatial distribution patterns of Merluccius capensis in the Namibian waters were investigated and related to average environmental conditions during 1996-2020. Fisheries-independent data and simultaneously collected water temperature and dissolved oxygen data were used from austral summer surveys. A geostatistical kriging approach was employed to evaluate the spatial structure of hakes. Links to environmental conditions were explored via data-driven generalized additive models (GAMs). M. capensis generally exhibited average patch sizes between 40 and 50 nm at depths between 180 and 280 m. During the extreme episodic water warming in 2011 related to a Benguela-Nino, the hake patches shrank up to a historical minimum of about 13 nm and moved offshore showing maximum densities at unusual deeper bottoms between 260 and 320 m. The deepening and size reduction of aggregations did not alter the biomass estimates (570 kt) that remained within historical ranges (249-811 kt). Although other extremely warm and cold summers were reported during the study period, no significant impact on the M. capensis patch size was detected. Maximum M. capensis densities were linked to optimal bottom temperature range between 10.1 and 11.8 degrees C, dissolved oxygen values close to zero nearshore, and between 0.8 and 1.4 ml/L offshore. Potential changes of biomass produced by extreme environmental events remained undetected within the interannual biomass ranges, suggesting a high resilience capacity to episodic extreme environmental events.

Context Overfishing has been historically considered as the main cause of fish stock depletion in the Magdalena River basin, Colombia, whereas the environmental context in which fisheries take place has not been considered. Aims The purpose of this research was to answer the following question: have anthropic activities, other than fishing, influenced the decrease in fishery production in the Magdalena River basin between 1980 and 2015? Methods We analysed diverse variables that were used as proxies for different environmental degradation processes, including sediment load, forest cover, flow rates, reservoir volume <1200 m above sea level, gold production and human population growth. We compared these variables with fishery production between 1980 and 2015 by using cluster analysis, principal-component analysis (PCA) and principal-component regression (PCR). Key results Our findings confirmed that environmental degradation accounts for 61% of the reduction of fishery production. Conclusions The traditional approach of holding fishers accountable for the decline of fishery production is misleading, and, therefore, a better understanding of the overall system is necessary before implementing restrictions on fishing activities. Implications Hence, fishery management should also integrate economic and social variables that affect ecosystem services within the basin into the analysis and decision processes.

Given the potential interest in targeting Solenocera acuminata in a new deep-sea fishery in the Colombian Caribbean, biological information is needed to support the management of this species. The objective of this study is to provide biological information about size structure, size at sexual maturity, morphometric relationships, abundances and spatial and bathymetric distribution of S. acuminata in the Colombian Caribbean. Specimens of S. acuminata were collected during four deep-sea prospecting surveys in the Colombian Caribbean Sea, which were conducted between Punta Gallinas and the Gulf of Uraba. A total of 87 exploratory fishing trawls were made between 100 and 550 m depth. Sexual dimorphism was evident, with males being smaller than females. The size at sexual maturity of the females was 95.2 mm total length (23.82 mm CL). Relatively high biomass values were found in the northern zone of the Colombian Caribbean, between Santa Marta and Riohacha. In the southern zone, higher biomass was found between Cartagena and Morrosquillo Gulf. The biomass of S. acuminata was higher at night (mean 1.82 kg/km2) than during daylight (mean 0.15 kg/km2). This species was distributed between 150 and 400 m depth and the highest biomass was associated with depths between 330 and 380 m. Before starting a new fishery, more research is needed to understand the life cycle parameters of deep-sea resources, such as growth, reproduction, recruitment, mortality, spawning areas and times, nursery areas and associated biodiversity.

The dwarf lanternshark (Etmopterus perryi) is the smallest known described shark and practically no information has been available on this species since first described in the mid-1980s. Therefore, the aim of this work is to describe, for the first time, the population structure regarding dwarf lanternshark in the Colombian Caribbean Sea. During deep-water research surveys conducted along the Colombian Caribbean coast, 87 stations were sampled using the swept area method. A total of 153 dwarf lanternshark individuals were caught in depths ranging from 230 to 530 m. This information was used to describe the size structures, morphological measurements including length-at-weight relationship, length at maturity in females, and the spatial distribution of mean length and biomass of the species. The lengths of individuals ranged from 78.02 to 289.00 mm total length (TL), which is a new record of maximum length for this species. The spatial distribution of mean lengths and biomass distributions show high abundances and high relative mean lengths in the northeast area off Santa Marta and the area northwest of Riohacha. The mean biomass density in the whole prospected area was 5.52 kg/km2 . Length at 50% maturity in females was estimated in 203 mm TL (95% CI: 190-214 mm). Deep-water elasmobranch species, such as the dwarf lantern shark, are expected show extremely low resilience to fishing exploitation, even when they are not targeted by commercial fishing. Therefore, the information reported in this study can serve as a baseline upon which management measurements can be proposed for the conservation of this shark species. This article is protected by copyright. All rights reserved.

The pink shrimp Penaeus notialis is one of the most important commercial species of the world. In the Caribbean Sea of Colombia, they represent 70 % of the catches in industrial fisheries, but since the 90’s it has shown a significant decrease in its abundances because of overexploitation of the resource. Because there are no studies on the genetic status of their populations in the Colombian Caribbean, the current management strategies for the pink shrimp can be improved with genetic criteria. Hence, the objective of this study was to examine the genetic diversity (Ho, He and Fis), structure population (Fst, AMOVA, Bayesian analysis, DAPC, Mantel test) and the connectivity (assignment analysis) in five localities distributed in the Caribbean Sea of Colombia (Zapatá, Arbolete, Isla Fuerte, Punta Canoa y Manaure). Additionally, we assessed the spatial distribution of size structure by geostatistical analysis to identify possible nursery areas and a relationship with the genetic structure observed. The genetic analyses using seven microsatellites loci, showed low genetic diversity (Ho < 0,35), high genetic potential (He < 0,93), high inbreeding (Fis> 0,6) and the presence of three populations (ФST2, 98 = 0,065; P < 0.001) showing significant adjustment to the isolation-by-distance model (r = 0,78, z = −27,92; p = 0,031). It is discussed how the life cycle of the species, geomorphological variations on the continental shelf and marine currents influence the spatial distribution of size structure and genetic lineages of the pink shrimp, as well as the implications of this type of studies in the sustainable management of this valuable fishing resource.

We determined size structure, sex ratio, and condition factor for the pink shrimp, Penaeus notialis Perez Farfante, 1967 in the Caribbean coast of Colombia, information essential for the design of management and conservation strategies to ensure a sustainable fishery. Total length (TL; +/- 0.01 mm) ranged from 79.47 to 192.80 mm TL (mean 148.21 +/- 17.75) for females and 79.00-181.83 mm TL (mean 122.52 mm +/- 12.55) for males. Statistically significant differences (P< 0.01) in size and weight (+/- 0.1 mg) between sexes were found year-round; males were smaller and weighed less than females. The sex ratio showed significant differences (P < 0.01) between the total number of females and males per total length class when compared with a 50% sex ratio. The monthly sex ratio showed significant differences between the number of females and males. The weight-length relationship showed positive allometric growth (b = 3.118) for females, whereas negative allometric growth (b = 2.663) was observed for males. The condition factor (K) ranged 0.0002-0.0023 (mean 0.0009 +/- 0.0007) for females and 0.0005-0.2179 (mean 0.0316 +/- 0.0642) for males.

The objective of this study was to assess the patterns in the spatial distribution, size structure, morphometric relationships, and relationships of biomass and size to sampling depth and distance to the coast of Penaeus notialis in the Colombian Caribbean. The biological data were collected on board a shrimp trawler. The females were larger and heavier than the males, which indicated distinct sexual dimorphism in body size. The cephalothorax length at 50% maturity in females was 26.49 mm, and in males, it was 15.13 mm. Relatively high biomass values were found in the southern zone of the study area at depths between 25.6 and 49.3 m and between 3.94 and 7.80 nmi (= 7.29-14.45 km) from the coast. We found a clear spatial structure of biomass and size in relation to depth, so that the fishing effort can be directed to the locations of the adult population.

The upwelling system off the southern Caribbean coast is probably the main source of the nutrients that support biological productivity in the oligotrophic Caribbean Sea. Subtropical underwater (SUW) that forms the subsurface salinity maximum in the Caribbean Sea is the main source of upwelled waters in this system. Profiles of salinity and temperature with depth derived from four oceanographic cruises and Argo floats showed that upwelled waters have a salinity that is similar to 0.11 g kg(-1) lower than the SUW in the central Caribbean Sea and a seasonal variation of approximately 0.09 g kg(-1) that reflects the rainy/dry seasons. In addition, the SUW is similar to 50 m shallower on the continental shelf slope (similar to 100 m) compared to the depth of the SUW in the central Caribbean Sea. The origin of these modified SUW was analyzed using the Mercator numerical model, which reproduces the main vertical characteristics of the subsurface salinity maximum. The modeled data showed that SUW upwelling off of the La Guajira Peninsula and Venezuela arrive into the system via an intense Caribbean Coastal Undercurrent (CaCU, mean speed similar to 0.28 m s(-1)). This current is formed in front of the Nicaragua platform from the divergence of subsurface water flow at the salinity maximum depth. The lower salinity observed in the upwelled waters may be the result of intense vertical mixing processes that could occur when the SUW are transported by the CaCU below the Panama-Colombia Gyre (PCG) region before reaching the upwelling zones. The mixing processes-involving double diffusion and mechanical turbulence driven by vertical shear of horizontal currents-were analyzed using the Turner Angle and the Thorpe scale, respectively. Below a depth of 200 m, double diffusion by salt fingers (diffusivities > 5 x 10(-5) m(2) s(-1)) was the main process of salt diffusion, generating a downward salt flux of >2 x 10(-2) g kg(-1) m d(-1) between the SUW and the North Atlantic Central Waters (NACW). Above a depth of 100 m, mechanical turbulent diffusion generates a salt flux towards the surface ranging 0.5-4 x 10(-2) g kg(-1)m d(-1), where double diffusion by salt finger is not possible. The diluted SUW is subsequently transported by the CaCU, connecting-at the subsurface level-the PCG region with the upwelling zones off of Colombia and Venezuela. As well as modifying the salt content of the coastal SUW, these mixing processes may also alter the nutrient content of upwelling waters, the ecosystem effects of which are still unknown.