<div>Background:&nbsp;Portunus trituberculatus is an important economic crab in the East China Sea. With the increase of tonnage and power of offshore fishing vessels, fishing intensity also increases, which has caused great pressure on P. trituberculatus resources. Protecting P. trituberculatus and achieving sustainable utilisation of resources are urgent problems that need to be solved. Therefore, protection and rational development of P. trituberculatus resources are important to accurately understand its spatial and temporal distribution. 
 
Methods: In this study, the temporal and spatial distribution predictive models of P. trituberculatus in the northern East China Sea were built on the basis of three analysis methods (generalised additive model [GAM], random forest [RF] and artificial neural network [ANN]) using bottom trawl survey data and environmental data from 2006 to 2007. The fitting and prediction performances of these three models were compared. 
 
Result: Season and sea bottom temperature were the most important factors on the distribution of P. trituberculatus. The fitting performance of ANNs was better than those of GAMs and RFs, but its predictive performance was worse than those of GAMs and RFs. Therefore, RFs was the appropriate model in predicting the distribution of P. trituberculatus in the northern East China Sea. The abundance of P. trituberculatus was significantly higher in summer than in other seasons (P&lt;0.01) and generally higher in the northern part of the study area than in the southern part in all seasons.</div>

​Spatial and Temporal Distribution of Portunus trituberculatus in the Northern East China Sea based on Different Modelling Approaches

Background: Crabs are one of the major marine fisheries resources in India and they are among the most valuable seafood species due to their delicious taste, nutritional value and economic importance. The knowledge of the feeding ecology of these crabs is particularly important to understand their ecological interactions, since the abundance of preferred prey organisms strongly affects their distribution, growth, reproduction, behavior and migration. 
 
Methods: The study&nbsp;was conducted&nbsp;along the Mangaluru coast, with fortnightly crab samples gathered from the Mangaluru fish landing centre from March 2021 - February 2022. Random sampling ensured the inclusion of all size categories and samples&nbsp;were analyzed&nbsp;for weight, morphometric measurements, sex and food and feeding habits. The level of stomach fullness&nbsp;was assessed&nbsp;visually and the contents&nbsp;were examined&nbsp;using Point&rsquo;s volumetric method, identifying food items at the lowest taxonomic level and grouping them into dietary categories.&nbsp; The vacuity index and Gastro-somatic index (GaSI)&nbsp;were calculated&nbsp;to describe the trophic behaviour of Portunus sanguinolentus. 
 
Result: Gut content analysis revealed that&nbsp;P. sanguinolentus&nbsp;fed predominantly on crustaceans (31.45%), fish (22.84%), molluscs (18.70%) and larger quantities of sand and debris (20.29%) and unidentified matters (6.68%). The presence of debris and unidentified matter in the foregut suggests that&nbsp;P. sanguinolentus&nbsp;is a bottom-feeding omnivore which feeds on fresh and decaying matter. Size-wise analysis of gut contents revealed that juveniles (&lt;80mm CW) preferred miscellaneous items followed by crustacean remains as their diet, sub-adults (80-100mm CW) crustaceans (42.65%) and miscellaneous (50.07%) and adults (&gt;100mm CW) had a solid preference for crustaceans and molluscs.

​Spatial and Temporal Distribution of Portunus trituberculatus in the Northern East China Sea based on Different Modelling Approaches

Feeding Ecology of Red Spotted Swimming Crab, Portunus Sanguinolentus (Herbst, 1783) along Mangaluru Coast, Karnataka

Spatial and Temporal Distribution of Portunus trituberculatus in the Northern East China Sea based on Different Modelling Approaches