Abstract A recent examination of Philometra nematodes from mangrove red snapper Lutjanus argentimaculatus (Forsskal, 1775) from the Karachi coast, Kemari was done in the years 2021–2022. The present study reported three new species of genus Philometra (Costa, 1845) (Nematoda: Philometridae) Philometra kolachii, Philometra lutjani and Philometra kemarii. A total of 140 fish samples were examined, and 76 were infected. The intensity of infected fish was 54.28%. In Pakistan, literature on Philometrid nematodes is limited, therefore, this research would be helpful for the documentation and enhancement of nematods in Pakistan. Forsskal, Forsskal (Forsskal 1775 coast 20212022 2021 2022 2021–2022 Costa, Costa (Costa 1845 Nematoda (Nematoda Philometridae kolachii kemarii 14 examined 7 5428 54 28 54.28% Pakistan limited therefore 177 2021202 202 2021–202 184 1 542 5 2 54.28 17 202120 20 2021–20 18 54.2 20212 2021–2 54. 2021–

Resumo Um exame recente dos nematóides Philometra do pargo vermelho de mangue Lutjanus argentimaculatus (Forsskal, 1775) da costa de Karachi, Kemari, foi feito nos anos 2021 e 2022. O presente estudo relatou três novas espécies do gênero Philometra (Costa, 1845) (Nematoda: Philometridae): Philometra kolachii, Philometra lutjani e Philometra kemarii. O total de 140 amostras de peixes foram examinadas e 76 estavam infectadas. A intensidade de peixes infectados foi de 54,28%. No Paquistão, a literatura sobre os nematóides Philometrid é limitada, portanto, esta pesquisa seria útil para a documentação e aprimoramento dos nematóides no Paquistão. Forsskal, Forsskal (Forsskal 1775 Karachi Kemari 202 2022 Costa, Costa (Costa 1845 Nematoda (Nematoda Philometridae Philometridae) kolachii kemarii 14 7 infectadas 5428 54 28 54,28% Paquistão limitada portanto 177 20 184 1 542 5 2 54,28 17 18 54,2 54,

Species of the family Lutjanidae constitute an important fishery resource in tropical marine areas worldwide and are intensely exploited because of their excellent commercial value and quality. In Colombia, the lane snapper Lutjanus synagris is considered vulnerable to overfishing due to its biological characteristics, habitat deterioration, and historical decrease in catch rates in regions where it used to comprise the highest percentage of the landings. In order to generate more biological information needed to make effective fishery management decisions and policies, the genetic structure of L. synagris was analyzed in three areas of the Colombian Caribbean (Santa Marta, Rosario Islands, and Capurganá) using microsatellite-type molecular markers. Fourteen primers reported for two phylogenetically close species (Rhomboplites aurorubens and Lutjanus campechanus) were analyzed, eight of which were polymorphic and informative for the species under study. All loci were found to depart from Hardy-Weinberg equilibrium due to marked heterozygote deficiency in all the populations studied. Both the analysis of molecular variance (total population Φst = 0.006, P = 0.022) and spatial analysis of molecular variance showed a slight statistically significant population structure (best F CT = 0.003, Φst = 0.007, P = 0.0001) that separated the Capurganá population from those of the other areas with no evidence of isolation by distance (Mantel test Rxy = 0.023, P = 0.057). The results suggest that the life history of the species and the regional oceanographic conditions play an important role in determining the genetic structure and the existence of two different genetic stocks that should be managed according to their population structure.

Las especies de la familia Lutjanidae constituyen un importante recurso pesquero alrededor de las zonas marinas tropicales en el mundo y son explotadas intensivamente por su excelente calidad y valor comercial. En Colombia, Lutjanus synagris o pargo rayado, podría considerarse vulnerable a la sobreexplotación debido a sus características biológicas, al deterioro de su hábitat y a la disminución histórica de su captura en regiones donde representaba el mayor porcentaje de la pesca. Con el ánimo de generar información biológica que permita apoyar decisiones y políticas más adecuadas de manejo pesquero se analizó la estructura genética de L. synagris en tres regiones del Caribe Colombiano (Santa Marta, Islas del Rosario y Capurganá) mediante marcadores moleculares tipo microsatélite. Para tal fin se evaluaron 14 cebadores reportados para dos especies filogenéticamente cercanas (Rhomboplites aurorubens y Lutjanus campechanus) de los cuales ocho fueron polimórficos e informativos para la especie en estudio. Se encontró que todos los loci estaban muy alejados del equilibrio de Hardy-Weinberg debido a una marcada deficiencia de heterocigotos observada en todas las poblaciones estudiadas. Tanto el análisis de varianza molecular (Φst en la población total = 0.006, P = 0.022) como el análisis espacial de varianza molecular mostraron una leve estructuración poblacional estadísticamente significativa (mejor F CT= 0.003, Φst = 0.007, P = 0.0001) que separó la población de Capurganá de las demás regiones sin evidencia de aislamiento por distancia (Prueba de Mantel Rxy = 0.023, P = 0.057). Los resultados sugieren un papel importante de la historia de vida de la especie y las condiciones oceanográficas predominantes en dicha región en la determinación de la estructura genética y la existencia de dos stocks genéticos distintos que deben ser manejados de acuerdo a su estructura poblacional.