Distribution Of Crabs Research Articles

Oyster grower perspectives on green crab (Carcinus maenas) interactions: using applied social science to inform research and engagement

Research that informs the New Hampshire Aquaculture industry, which has grown significantly over the past few years, and helps the overall associated watershed community to keep Great Bay Estuary healthy is vital. Specific study of green crabs, Carcinus maenas, and their potential effects on oysters, Crassostrea virginica, is important to gain a better understanding of the impact invasive species may have on these ecologically and economically important bivalves. The aim of this study was to document and understand New Hampshire (NH) oyster growers’ perspectives on the issue of green crab predation of oysters. Through a survey, this study documented a preliminary understanding of farmer perspectives and research needs regarding the population of green crabs in NH waters. More specifically, this survey provided a social science perspective and information on areas of potential research - abundance, distribution, and diet of green crabs - that could be beneficial to the oyster industry. This study fills knowledge gaps, helps improve future research (including how to better engage with end users), and facilitates creating and implementing solutions that benefit the NH oyster aquaculture industry.

Occurrence data of the Atlantic Blue Crab (Callinectes sapidus, Rathbun, 1896) Indicates that a New Indwelled is Settling in the Black Sea

It is remarkable that blue crabs have been encountered frequently in recent years, especially on the southern coast of the Black Sea, after it was first reported in 1968. Reporting of three new records for blue crabs was tried to identify suitable areas for possible blue crab distribution in the Black Sea based on environmental variables, and past occurrence records. Ecological niche modeling was applied for this and the most contributing environmental variables were determined as maximum bathymetry, maximum mean salinity, and nitrate. It turned out that especially shallow areas on the coast of the Black Sea can be suitable habitats for blue crabs.

Mapping the habitat distribution of horseshoe crabs (Tachypleus gigas) in Pamekasan, Madura Island, Indonesia

Abstract Horseshoe crabs, often known as Belangkas or Mimi, is one of the ancient marine faunas with protected conservation status. Horseshoe crabs are distributed in coastal waters of Indonesia of the islands of Sumatra, Java, Kalimantan, and Sulawesi, which are often caught as bycatch. Horseshoe crabs’s bloods were uniquewhich contain amebocytes as a test material for the presence of endotoxin bacteria. The purpose of this study was to identify the species of horseshoe crabs and to analyze environmental conditions, as well as the distribution of horseshoe crabs in the coastal waters of Pamekasan, Madura Island. This study was conducted in June 2023 by collecting data from crab fishers. ArcGIS was applied to delineate the distribution of horseshoe crab. The identification results showed that there was one species horseshoe crab of the Tachypleus gigas in the waters of Polagan Village, Galis District, Pamekasan Regency. The environmental condition of the waters in Polagan Village, Galis District, and Pamekasan Regency was relatively good. Habitat mapping is one way to protect these animals from the threat of extinction and support conservation efforts.

Update on the geographical distribution of freshwater crabs of the Pseudothelphusidae family in the semi-arid region of northeastern Brazil

The humid forest zones of northeastern Brazil are recognized as endemic hotspots for pseudothelphusid crabs. In this study, we report new occurrence records of the pseudothelphusids, Fredius ibiapaba and Kingsleya attenboroughi, in humid soil and streams within humid forests of the semi-arid region of northeastern Brazil. These new records expand the geographical distribution of these crabs, highlighting their potential to inhabit humid forests throughout this region. Furthermore, this information indicates that these crabs, especially K. attenboroughi, are not confined to slopes and patches of humid forests in highland swamps but can also extend to springs in other areas of the Brazilian semi-arid region.

Updated and Corrected List of Hosts of European Pinnotherids (Crustacea, Decapoda, and Pinnotheridae): Relationship between Number of Hosts and Distribution

The present work provides an updated and corrected list of hosts for the five European species of pinnotherid crabs, taking into consideration all recent published works as well as new data obtained in the present study. In relation to the number of hosts, there are two groups of species, one composed by Pinnotheres pisum and Afropinnotheres monodi with the highest number of hosts, and a second group, with a reduced number of hosts and more specific taxa, consisting of three other species: Nepinnotheres pinnotheres, Pinnotheres bicristatus, and P. pectunculi. When studying the relationships between host preferences, host distributions, and pea crab distributions, we could not find a clear direct relationship between these parameters. Temperature is also probably an important influence and relevant factor responsible for the distribution of pinnotherid crabs, and this may be independent from the potential distribution due to the distribution of hosts.

First record of two species of brachyuran crab (Crustacea: Decapoda) Austruca albimana (Kossmann, 1877) and Tirmilyra concinnus (Ghani and Tirmizi, 1995) from India

This study reports the first record of two brachyuran crab species, Austruca albimana Kossmann, [21] and Tirmilyra concinnus Ghani and Tirmizi [18], from the western Indian coast. Their identification, taxonomic observations, and geographic distribution are provided. The species belong to the families Ocypodidae and Leucosiidae, respectively. This is the first report from Indian waters, as the species are so far reported from Oman, Iran and Persian Gulf. These records emphasize the need for research and conservation efforts in the region to explore the diversity and distribution of brachyuran crabs in Indian waters.

Estimation of pop-up satellite archival tag initial surface position: applications for eastern Bering Sea crab research

BackgroundClimate change is reshaping Bering Sea crab distributions and recent population declines have elevated the urgency in understanding spatial dynamics in relation to management boundaries. While pop-up satellite archival tags (PSATs) can provide fishery-independent movement information, a high level of spatial resolution is needed to evaluate small-scale (i.e., 10 s of km) movements of crabs. Because PSATs drift at the surface prior to acquisition of a satellite-estimated location (via Argos), the accuracy of pop-up location (i.e., animal terminal position) estimates depends on the ability to accurately estimate drift error. We deployed PSATs (n = 36) on fixed-position moorings in Bristol Bay and Marmot Bay, Alaska to validate a new method to estimate tag pop-up location and an associated error ellipse that uses in situ drift data from surfaced tags to estimate drift error. Estimated pop-up location was compared to the location of tag surfacing (i.e., the tag’s fixed position) and to an alternative estimate (i.e., an early satellite-estimated location). Additional tags were deployed on mature male red king crab (Paralithodes camtschaticus) in Bristol Bay during 2020 (n = 84) and 2021 (n = 90) to compare estimates of tag drift error and crab displacement derived using the method.ResultsFor red king crab tags with pop-up location estimates in 2020 (n = 79) and 2021 (n = 46), mean drift error was 9% and 44% of mean crab displacement, respectively. For fixed-position PSATs with pop-up location estimates (n = 27), mean distance between the estimated pop-up location and the tag’s fixed position was 2.0 km, representing a mean improvement in accuracy of 51% over alternative estimates. Corresponding error ellipse estimates either encompassed the tag’s fixed position (n = 11) or their boundaries were a mean distance of 1.3 km (n = 16) from the fixed position.ConclusionsOur method improves pop-up location estimates for PSAT-tagged animals and is particularly well suited for crabs and other slow-moving benthic marine species. The improved estimates enhance PSAT utility for addressing management and ecological questions that require a fine spatial resolution, such as movement near management boundaries or defining essential habitat for important life history events.

Expansion of the Distribution Range and Size of the Invasive Blue Crab on the Turkish Coast of the Black Sea

The blue crab (Callinectes sapidus Rathbun, 1896) is an euryhaline species originally native to the western Atlantic Ocean. However, it has expanded its range into the Black Sea, including the Turkish coastal waters. Blue crab specimens were sampled along the Black Sea coast of Türkiye, covering the stretch from Cape Taşkana to the Georgian border. The monitoring studies spanned the period from 2017 to 2024. Analysis of the 16 specimens revealed a carapace width range of 14.8 to 20.3 cm, with males exhibiting larger sizes compared to females. Notably, two of the sampled females were observed to be carrying eggs, highlighting reproductive activity in the region. This study also reports the discovery of the largest blue crab ever recorded on the Turkish coasts of the Black Sea, with a male specimen measuring 20.33 cm in carapace width and weighing 565.1 g. Additionally, a male specimen sampled in the Rize region suggests the species has expanded its range to the easternmost part of the Black Sea. The findings contribute significantly to our understanding of the distribution and growth potential of the blue crab in the Black Sea. The larger sizes observed in males and the presence of ovigerous females indicate successful adaptation and potential establishment of a self-sustaining population. As invasive species, blue crabs can significantly influence benthic communities and food chains, highlighting the importance of a prudent management approach to fisheries biology and ecosystem management

Investigation of the population diversity of intermediate host snails and crabs of Paragonimus along Jiulong River, Zhangjiang River and Dongxi River basins in southern Fujian Province

To investigate the population distribution of intermediate host snails and crabs of Paragonimus along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, so as to provide baseline data for researches on parasitic disease prevention and control and enlargement of samples in the parasitic resource bank. A total of 23 villages in 8 counties (districts) along the Jiulong River, Zhangjiang River, and Dongxi River basins in Zhangzhou City, Fujian Province were selected as survey sites during the period from November 2020 through March 2023, and snail and freshwater crabs were sampled from 1 to 3 streams and ditches neighboring residential areas in each village. Morphological identification of snails was performed according to the external morphological characteristics of collected snail shells, and the unidentified snail species sampled from the natural foci of paragonimiasis in Yunxiao County were subjected to se-quence analysis of the mitochondrial cytochrome oxidase 1 (CO1) gene. The crab species was identified by observing the morphological characteristics of the terminal segment of the first pleopod of male crabs, and Paragonimus cercariae and metacercariae were detected in collected snails. The shells of the unidentified snails sampled from the natural foci of paragonimiasis in Yunxiao County were approximately 50 mm in height and 18 mm in width, thick and solid, long tower cone-shaped, and had 8 to 10 whorls. CO1 gene sequence analysis identified the snail species as Sulcospira hainanensis. A total of 6 freshwater snail species belonging to 5 genera within 3 families, identified 23 survey sites, including Semisulcospira libertina, Paludomus zhangchouensis and S. hainanensis that belonged to the Family Pleurceridae, Tricula fujianensis and T. huaanensis that belonged to the subfamily Triculinae, Family Pomatiopsidae, and Melanoides tuberculata (Family Thiaridae), and 11 species of freshwater crabs belonging to 5 genera within 2 families were identified, including Sinopotamon genus of S. jianglense, S. pinheense, and S. zhangzhouense, Huananpotamon genus of H. planopodum and H. zhangzhouense, Nanhaipotamon genus of N. huaanense and N. longhaiense, and Minpotamon genus of M. nasicum and M. auritum that belonged to the Family Potamidae, and Somanniathelphusa genus of S. huaanensis and S. zhangpuensis (Family Parathelphusidae). In addition, the prevalence of P. westermani cercariae infections was 0.08% (2/2 317) in P. zhangchouensis from Danyan Village in Changtai District and 0.09% (1/1 039) in S. hainanensis from Jinkeng Village in Yunxiao County, and the prevalence of P. westermani metacercariae infections was 25.81% (8/31) in S. jianglense from Danyan Village in Changtai District, and 26.31% (5/19) in S. zhangzhouense from Jinkeng Village in Yunxiao County, respectively. There is a population diversity in the intermediate host snails and crabs along the Jiulongjiang River, Zhangjiang River, and Dongxi River basins in Bopingling Mountain, southern Fujian Province, and P. zhangzhouensis and S. hainanensis are, for the first time, confirmed as the first intermediate hosts of P. westermani.

Abundance and Distribution of Blue Swimmer Crab in Response to Environmental Variation Across Two Contrasting Estuaries

Portunid crabs are an iconic, high value species in NSW, but catches are highly variable in space and time. Substantial variation in biomass is observed in both exploited and unfished populations, and environmental effects on distribution and abundance are an important factor contributing to this variability. Predicting and responding to this variability is a challenge for management and sustainability of exploited populations. We examine spatial and temporal variation in Blue Swimmer Crab (Portunus armatus) populations, over a 2.5 year trapping survey in two temperate estuaries that differ in tidal flow and riverine input. Specifically, monthly catch rates and distribution throughout the estuary are examined alongside variation in temperature and conductivity. In Wallis Lake, the shallower estuary with a restricted entrance, both water temperature and conductivity impacted abundance and distribution of crabs but there was no evidence that pulses of freshwater flow had a major impact. For a 10 °C increase in temperature the population on average shifted ~ 700 m closer to the ocean. Males were consistently located slightly further into the estuary compared to females, but there was no convincing evidence of estuarine egression in response to lower salinity. In Port Stephens, the deeper, tidal estuary, water temperature and conductivity also impacted abundance, but while males were more dispersed than females, the distribution of crabs within the estuary did not appear to be influenced by temperature, conductivity or flow. These results highlight the links between nuanced environmental relationships and estuarine geomorphology for Blue Swimmer Crab.

Karakteristik Biologi dan Kelimpahan Rajungan (Portunus pelagicus) di Sekitar Perairan Sumenep

The high demand for the crab export market has resulted in the crab commodity experiencing a decline and leading to exploitation. Prediction of crab stocks in Sumenep Regency is minimal due to a need for further information regarding crab data. This study aims to determine the biological characteristics of the blue swimming crab (Portunus pelagicus), limiting blue swimming crab (Portunus pelagicus), and water quality characteristics around Sumenep. Research methods is observation methods or directly contact fishermen. Data collection included blue swimming crab biology, including morphometric aspects, which consisted of measurements of carapace width, carapace length, weight, and level of gonadal maturity. Data collection for water quality parameters used the insitu method at each research location. The results of this study were variations in the morphometric characters of the crabs in the distribution of the carapace width of the male crabs found in class 121-138 mm, as many as 137 individuals, while the female crabs were found in class 121-138 mm as many as 136 individuals, the distribution of size class based on the length of the female crab in class 60 .42-68.42mm as many as 112 people. The size class distribution of male crabs was mainly found in the 51.42-59.42mm class of 96 individuals; the distribution of size classes based on the weight in male crabs in the 126-157 gram class was 65 individuals. The size class of female swimming crabs was found in the 158-189 gram class; as many as 67 individuals applied for crabs around Sumenep. Based on the crab data collection at the first location, Talango was 289 ind/700 cm2, the second location was Tanjung Saronggi, 65 and/700 cm2, and in the third location, Gili Genting, there was as much as 104 ind/700 cm2. The waters of Tanjung Saronggi are a location that has more male crabs than female crabs. The air quality characteristics around Sumenep waters are categorized as optimal for blue swimming crab habitat.

Goliath is not the enemy: Fiddler crab species of similar size are stronger competitors than their larger adversaries in the climate change context

Many intertidal species are expanding their distribution limits towards the poles as a consequence of increased temperature due to climate change. At the same time, some intertidal habitats have been reduced due to rising sea levels. Fiddler crabs inhabit mangroves, and different species occupy well-established zones. Due to the restricted mangrove areas and consequent latitudinal expansion of the species, the distribution and density of fiddler crabs may be subject to change. The overlap forces several species to cohabit in a smaller territorial space. Fiddler crab species can vary in size, which could decisively affect territorial competition. Using Leptuca urguayensis as a reference, we tested how competing species of different sizes (larger size: L. thayeri and Minucapanema; similar size: L. cumulanta and L. leptodactyla) might interact in future climate change scenarios. First, we showed that within the territory of L. uruguayensis, the species L. cumulanta and L. thayeri occurred mainly in the lower mesolittoral zone, while L. leptodactyla and M.panema predominated in the upper mesolittoral zone. In a laboratory experiment, we evaluated whether the density and size of the heterospecific competitors could alter the agonistic behavior of Leptuca uruguayensis. Our results indicated that increasing the density can increase the agonistic behavior of L. uruguayensis with a greater intensity against species of a similar size. In a second field experiment, we demonstrated that the presence of a burrow enhances the intensity of agonistic interactions between L. uruguayensis and species of similar size. Therefore, in a scenario of territorial expansion of fiddler crabs due to climate change, it is expected that similarly sized species represent a greater competitive threat to populations of L. uruguayensis.

Restoration promotes ecological functioning through greater complementarity

Restoration projects are increasingly widespread and many promote habitat succession and the diversity and abundance of faunal communities. These positive effects on biodiversity and abundance may extend to enhancing the ecological functioning and resilience of previously degraded ecosystems, but this is rarely quantified. This study surveyed a 200‐ha restoring coastal wetland and three control wetlands in the Maroochy River, eastern Australia to compare the effects of wetland restoration on the consumption of carrion and the biodiversity, abundance, and functional diversity of functionally important fish and crustaceans. Carrion consumption by fish and crustaceans was measured every 6 months from spring 2017 until spring 2021 for nine events using a combination of baited cameras and scavenging assays. We found restoration improved rates of carrion consumption and the biodiversity, functional diversity, and abundance of scavenger species. Despite positive effects on the diversity of scavengers and carrion consumption, the abundance of two species, longfin eels (Anguilla reinhardtii) and mud crabs (Scylla serrata), was the most important predictors of carrion consumption rates. The spatial distribution of carrion consumption was concentrated in areas with high saltmarsh extent, moderate to high mangrove extent, and high salinity, which also resembled the distribution of both longfin eels and mud crabs. We show that restoration can promote the rates of key ecological functions but that increases to functions are likely to be characterized by low functional redundancy and greater complementarity. Therefore, maintaining or increasing the abundance of functionally important species should become a key objective in future restoration projects.

First record of goneplacid crab, Carcinoplax haswelli (Decapoda: Brachyura: Goneplacidae) from the Indian Ocean

Abstract A single male specimen of Goneplacid crab, Carcinoplax haswelli (Miers, 1884) is recorded for the first time from the Indian Ocean. The crab specimen was collected from the trawl bycatch landing of the commercial demersal trawler operated between 30 and 150 m depth along the Gujarat coastal region, Northwest coast of India. This C. haswelli is previously recorded from northern Australia and Taiwan to South China Sea. Until now, C. haswelli is not observed or recorded from the Indian Ocean. In the present study, detailed information regarding the taxonomic identification and previous distribution of the goneplacid crab, C. haswelli is described.

Size Distribution and Habitat Characteristics of Coconut Crabs (Birgus latro) in Tomajiko, Hiri Island District, Ternate City, Province North Maluku

Coconut crabs (Birgus latro) is a fishery resource that is only found in eastern Indonesia, and the waters of Ternate City are an area that has this potential. This research aims to determine the size distribution and habitat characteristics of coconut crabs in Tomajiko, Hiri Island District. The data collection method consists of several stages, namely determining stations, distributing bait, catching coconut crabs, morphometric measurements, and observing environmental parameters. Determination of stations in this study was carried out based on topographic differences in Tomajiko (divided into two stations). Coconut crab catching uses the roaming survey method. The bait used is coconut meat that has been split into several parts and coconut meat that has been mashed. The morphometric dimensions measured were chest length (carapace length) and body weight. The habitat characteristics observed were the type and extent of vegetation, organic matter content and substrate texture, environmental parameter measurements (soil temperature, air humidity and soil pH). The results of the research showed that the coconut crabs caught at both stations had relatively the same length, but the largest weight was found at station 2. Habitat characteristics in Tomajiko, Hiri Island strongly support the survival of coconut crabs.

Pemetaan Sebaran Rajungan yang ditangkap menggunakan Bubu Di Perairan Pesisir Barat Lampung

The Pesisir Barat of Lampung is one of the locations that has great opportunities for capture fisheries activities in Lampung. The abundant potential of these waters means that people in Pesisir Barat Regency earn income from fishing along these waters. Fishermen still catch fish using traditional tools using small boats (jukung). The vast waters with muddy and sandy water substrates make fishermen use fishing gear that is cheap, easy to operate and environmentally friendly. The trap fishing gear is a passive fishing gear operated by fishermen whose main catch is crab. The aim of this research is to map the distribution of crab catches using trap fishing gear. This research was carried out from June 2023 to September 2023. The research location was carried out in West Coastal Waters. Mapping crab fishing areas begins with identifying crab fishing areas. Identification of crab fishing areas is carried out using a survey method on three indicators, namely the location of fishing operations, catch results and environmental conditions. These results show that the distribution of crabs using trap fishing gear on the West Coast is at the Fishing Ground in Kuala Stabas Waters, Bengkunat Bay Waters and Labuhan Tapokan Waters with the number of crabs on LED trap fishing gear being 250 and the number of crabs on trap fishing gear without LEDs being 250. 119 Tails

Impact of Mangrove Deforestation on Fiddler Crab Distribution and Soil Physico-chemistry at Eagle Island, Rivers State

Mangrove forest in the Niger Delta and its associated biotic and abiotic has been greatly impacted by several factors, some natural and others anthropogenic in nature. Anthropogenic activities have negatively affected the organisms that inhabit the forest resulting in the decrease in size of population of fiddler crabs (Uca tangeri). To investigate the influence of anthropogenic activities on the mangrove habitat, burrow distribution and population of fiddler crabs and soil physico-chemistry were determined in forested and deforested sites. Burrows and number of crabs outside burrows were counted while samples of soil were retrieved and moved to the laboratory for the determination of cadmium (Cd), lead (Pb), total hydrocarbon content (THC) and Zinc (Zn) using atomic absorption spectrophotometer. The conclusions show a lack of significant difference in burrow distribution between forested and deforested areas (P>0.05). Contrastingly there is significance in the difference in crab population in forested and deforested sites. (P<0.05), which showed that there were more crabs in deforested areas than forested areas. There was also a significant difference in chemical and microbial population (P<0.05). There was higher THC in deforested areas, which was probably impacted by the heavy-duty vehicles used to cut down the trees. The result implies that human activities of deforestation and pollution influence crab population and soil physicochemistry in mangrove forest.

Using Public Sightings to Document the Widespread Distribution of the Non-Endemic Blue Land Crab, Cardisoma guanhumi, in South Carolina

Using Public Sightings to Document the Widespread Distribution of the Non-Endemic Blue Land Crab, Cardisoma guanhumi, in South Carolina

Sustainability for stakeholders and the environment? Understanding the role of geographical indications in sustaining agri-food production

The literature presents a debated discourse on the promotion of sustainable food production through Geographical Indications (GIs) certification. This study investigates the role of GIs in sustaining agri-food production based on a qualitative case study of hairy crabs with GIs in Suzhou, China. I collected secondary documents and conducted participant observation and interviews with food producers, food consultants, tour operators, and government officials. The findings suggest that, although the potential of GIs to expand agricultural economic prospects is probed, the increasing economic value of hairy crabs, especially those designated as GIs, incentivises farmers to expand crab breeding zones. This expansion, accompanied by animal feed, caused water pollution. The government's protective measures are meant to preserve the ecosystems. However, these measures have resulted in social inequalities in that some farmers are excluded from the production and distribution of lake crabs, and the local industrial chain is somewhat disrupted. These findings are discussed by linking to the previous studies, thus enriching the literature on GIs.

Investigating the impact of introduced crabs on the distribution and morphology of littorinid snails: Implications for the survival of the snail Littorina saxatilis

Introduced species can have profound impacts on communities by displacing and consuming native organisms. The intertidal communities in the Gulf of Maine have been radically altered through a suite of invasions in the early 1800s, including the herbivorous snail Littorina littorea and the omnivorous European green crab Carcinus maenas leading to morphological and distributional changes in two native gastropod grazers (Littorina saxatilis and Littorina obtusata). Green crabs and native cancrid crabs occupy the mid to low intertidal zones, leaving the high intertidal zones relatively free from crab predation pressure. However, a more recent invasion in the 1980s by the intertidal omnivorous Asian shore crab Hemigrapsus sanguineus, has eliminated this predator-free zone in the high intertidal. This invasion is of particular concern to populations of L. saxatilis, which were relegated to the high intertidal through combined competition and predation pressure by L. littorea and C. maenas. In order to quantify the potential impact of H. sanguineus on native snails, we conducted both field and lab experiments, testing the susceptibility of different sized snails to predation by introduced crabs. Additionally, we measured the distribution, abundance, and morphology of intertidal snails and crabs. Smaller snails of all species were the most susceptible to predation, although susceptibility differed among snail species and predation capabilities differed among crab species. L. saxatilis was the most vulnerable snail species to predation, with 73 and 64% of the population susceptible to large H. sanguineus and small C. maenas, respectively, while >96% of the L. littorea population was resistant to predation. L. saxatilis has been relegated to the high intertidal where there is high abiotic stress and poor-quality food, but until the invasion of H. sanguineus, there was little predation risk. This added predation pressure may further threaten populations of L. saxatilis, especially as the upper intertidal becomes more hostile with increasing temperatures and possible species introductions.