Implications of habitat-specific growth and physiological condition on juvenile crab population structure

2008 ◽  
Vol 59 (8) ◽  
pp. 726 ◽  
Author(s):  
Valter Amaral ◽  
Henrique N. Cabral ◽  
José Paula

Post-settlement processes can regulate the size and structure of marine invertebrate and fish populations. Faster growth and better physiological condition generally increase the survival potential of early juveniles, being usually associated with structurally complex habitats. Successive cohorts of early juvenile Carcinus maenas were followed in sandy and seagrass (Zostera noltii) habitats in the Mira Estuary, Portugal, to estimate growth and physiological condition (evaluated by RNA/DNA ratio) of juvenile populations. Mean cohort growth was similar in both habitats. However, in the sandy habitat, population size structure progressed to cohorts of larger carapace width (CW) and the RNA/DNA ratio was always higher than in the Z. noltii habitat. In this habitat, cohorts of low CW prevailed throughout and RNA/DNA ratio only increased after ~5.0 mm CW. Higher densities characterising seagrass areas may result in higher competition for resources, limiting growth and condition and leading to dispersal to less populated habitats. Larger juveniles had the best physiological condition, especially early in the season. Seagrass habitats do not necessarily yield enhanced growth rates and physiological condition of early juvenile crabs in relation to sandy areas. Knowledge of such trends is vital to understand distribution and abundance patterns of fish and marine invertebrate populations.

2015 ◽  
Vol 2 (6) ◽  
pp. 140482 ◽  
Author(s):  
Ines Fürtbauer

While the literature on consistent individual differences in correlated suites of physiological and behavioural traits is steadily growing for vertebrates, invertebrates have received less attention. The few studies that do exist have measured temporary physiological states (or responses), rather than consistent individual physiological traits. Here, I explore the consistency of individual differences in physiology and behaviour of n =53 shore crabs ( Carcinus maenas ) by repeatedly measuring haemolymph density (HD) and the crabs' responses to a novel environment. In crustaceans, HD is directly proportional to protein concentrations, and thus indicative of physiological condition. HD was highly repeatable, and crabs showed consistent individual differences in their behavioural responses to a novel environment, thus indicating individual consistency in both physiology and behaviour. Furthermore, HD was significantly correlated with the crabs' risk propensity, i.e. individuals with higher HD spent more time near shelter. Overall, this provides the first evidence for consistency in an endogenous physiological trait in an invertebrate. The link between consistent physiology and behaviour, i.e. coping styles, analogous to those found in vertebrates, suggests metabolic and/or immunological correlates of personality which offer great potential for future studies.


Author(s):  
S. Mathieson ◽  
A.J. Berry ◽  
S. Kennedy

In the Forth Estuary, Scotland, parasitic rhizocephalan barnacle Sacculina carcini externae or scars occurred on 64% of Carcinus maenas from the subtidal channel of the middle estuary. These became more frequent downstream, infecting 46·9% in the lower estuary basin. Male and female crabs were infected equally, and infection rates in low-tide samples did not differ from high-tide. The parasites occurred most frequently on crabs of 40–50 mm carapace width (CW) rather than the modal crab size class of 50–60 mm. Downstream, proportionately more smaller than larger crabs bore parasites whereas, further upstream, more larger than smaller crabs bore parasites. There is evidence for the annual appearance of new externae in July-October, especially in the lower estuary basin, followed by their growth and loss after about a year.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7845
Author(s):  
Allan T. Souza ◽  
Felipe O. Ribas ◽  
João F. Moura ◽  
Claudia Moreira ◽  
Joana Campos ◽  
...  

Intraspecific agonistic interactions are widespread across the animal kingdom, with many individual morphological and physiological characteristics playing important roles in the fate of disputes. Additionally, changes to environmental conditions can influence the outcomes of animal contests. The shore crab (Carcinus maenas) is a globally distributed species, present in numerous coastal and estuarine temperate systems around the world. Although shore crabs are highly tolerant to changes in temperature, this parameter has important physiological effects on the species’ ecology, while its effects on behavior are not fully understood. Our study aims to investigate how different individual characteristics (such as sex, color morphotype, carapace and chela morphology) and temperature conditions affect the dyadic interactions between shore crabs when disputing food resources. In general, the differences in carapace width between opponents, their sexes, color morphotypes and the temperature conditions interacted and were important predictors of the contest fate. We found that the body size and color morphotype of C. maenas determined the fate of dyadic disputes. However, the higher temperatures disrupted the well-established dominance of the larger red color morphotype individuals. Overall, the agonistic contest results suggest higher plasticity than previously acknowledged.


2019 ◽  
Vol 8 (4) ◽  
pp. 402-408
Author(s):  
Nathanael Ganang Anindityo Wibowo ◽  
Chrisna Adhi Suryono ◽  
Ibnu Pratikto

Rembang merupakan salah satu kabupaten di Jawa Tengah yang dikenal sebagai daerah penghasil sumberdaya rajungan yang cukup tinggi permintaannya dan terus meningkat setiap tahunnya. Hal tersebut dapat menyebabkan terjadinya penurunan potensi hasil rajungan akibat intensifnya penangkapan di Perairan Rembang. Kajian tentang kondisi stok sumberdaya rajungan  terkait sebaran dan dinamika populasi ini sangat diperlukan dalam pengelolaan potensi rajungan. Tujuan dari penelitian ini adalah untuk menganalisis struktur ukuran dan parameter pertumbuhan rajungan di Perairan Rembang. Penelitian ini dilaksanakan pada bulan Maret – Juni 2019 di Perairan Rembang, dengan menggunakan metode survei yang bersifat deskriptif. Total sampel rajungan selama penelitian adalah 1200 ekor yang terdiri dari 574 ekor jantan dan 624 ekor betina. Hasil penelitian menunjukkan kelas ukuran lebar karapas rajungan didominasi oleh rajungan muda, dengan rata – rata 105.01 ± 11.99 mm untuk jantan dan 107.73 ± 10.68 untuk betina. Berat rata – rata rajungan jantan yaitu sebesar 95.2 ± 27.1 gram dan rajungan betina sebesar 97.9 ± 23.1 gram, sehingga menunjukkan rajungan jantan lebih kecil dibandingkan dengan rajungan betina. Pola pertumbuhan rajungan di Perairan Rembang bersifat allometrik negatif. Laju pertumbuhan rajungan di Perairan Rembang yang didapatkan adalah berupa nilai panjang asimptotik (L∞) sebesar 71.4 mm dengan koefisien pertumbuhan (K) sebesar 1.5/tahun.Rembang is a coastal region in Central Java which known as to producer of blue swimming crab resources that are in high demand and continues to increase every year. It will because decreasing the potential yield of blue swimming crab due to intensive fishing in Rembang Waters. Study on the stock condition of the blue swimming crab resource related to the distribution and dynamics of the population is required for the management of the blue swimming crab potential. The current research aims to assess the size structure and growth parameter of blue swimming crab in the Rembang Waters. The research was conducted from March to June 2019 in Rembang Waters, using a descriptive survey method. The total number of crab samples during the study was 1200 animals consisting of 574 male and 624 female. The results showed that the size of the crab carapace width class was dominated by young crabs, with an average of 105.01 ± 11.99 mm for males and 107.73 ± 10.68 for females. The average weight of male crab is 95.2 ± 27.1 gram and female crab is 97.9 ± 23.1 gram, indicates that male crab is smaller than female crab. The crab’s growth in Rembang Waters is allometric negative. The growth rate of crab in the Rembang Waters obtained is in the form of asymptotic length (L∞) was 71.4 mm with a growth coefficient (K) 1.5/year.


2017 ◽  
Vol 15 (2) ◽  
Author(s):  
M. Tahmid, Achmad Fahrudin Dan Yusli Wardiatno

ABSTRAKKepiting bakau (Scylla serrata) merupakan salah satu potensi komoditas perikanan skala kecil yang memiliki nilai ekonomi tinggi. Kelimpahan populasi dipengaruhi oleh upaya penangkapan dan kondisi ekosistem mangrove sebagai habitat utamanya. Produksi kepiting bakau di Teluk Bintan menurun dan penyebabnya belum diketahui dengan pasti. Oleh karena itu, perlu dilakukan kajian tentang biologi kepiting bakau di Teluk Bintan. Penelitian ini bertujuan untuk mengkaji status populasi kepiting bakau yang meliputi struktur ukuran, parameter pertumbuhan dan laju mortalitas dan eksploitasi. Pengambilan data kepiting bakau dilakukan dengan pendekatan yaitu fisher-based survey. Hasil penelitian menunjukkan ukuran kepiting bakau yang tertangkap mulai dari lebar karapas (CW) 64-172 mm, ukuran fase muda kepiting jantan yang tertangkap mencapai 46,62% dan betina mencapai 48,06%, keduanya hampir setengah dari tangkapan total, ini menunjukkan bahwa alat tangkap yang digunakan belum selektif. CW∞ jantan mencapai 176,93 mm lebih tinggi dari kepiting betina sebesar 169,58 mm, namun sebaliknya nilai koefesien K jantan (0,360) lebih kecil dari betina (0,390), sehingga pertumbuhan kepiting bakau betina lebih cepat dari jantan. Perkiraan angka kematian alami (M) jantan = 0,5566 dan kematian akibat penangkapan (F) jantan = 0,6434 sedangkan M betina = 0,59 dan F betina = 0,41. Laju eksploitasi (E) kepiting jantan mencapai 53,62%, ini dapat dikatakan telah terjadi lebih tangkap atau over eksploitasi. Kata kunci: Scylla serrata, parameter pertumbuhan, struktur ukuran, mangrove and Teluk Bintan ABSTRACTMud crab (Scylla serrata) is one of the potential of small-scale fishery commodities that have high economic value. The abundance of the population is affected by the fishing effort and conditions mangrove ecosystem as its main habitat. Mud crab production in the Gulf of Bintan declined and the cause is not known with certainty. Therefore, it is necessary to study on the biology of mud crab in the Gulf of Bintan. This study aims to assess the status of mangrove crab population that includes the size structure, parameters of growth and the rate of mortality and exploitation. Data retrieval is done with a mangrove crab fisher-based survey. The results showed that the size of mud crab caught from carapace width (CW) 64-172 mm, the size of the young phase male crabs caught females reached 46.62% and reached 48.06%, both are almost half of the total catch, it indicates that fishing gear used is not selective. CW∞ males reach 176.93 mm higher than the female crabs of 169.58 mm, but instead value koefesien K males (0.360) is smaller than females (0.390), so that the growth of female mud crabs faster than males. Estimated natural mortality rates (M) male = 0.5566 and deaths from arrest (F) male = 0.6434 while M females female F = 0.59 and = 0.41. The rate of exploitation (E) male crabs reached 53.62%, can be said to have occurred over fishing or over-exploitation. Keywords: Scylla serrata, growth parameters, structure size, mangrove and bay Bintan


2021 ◽  
Vol 10 (2) ◽  
pp. 175-183
Author(s):  
Iqbal Maulana ◽  
Irwani Irwani ◽  
Sri Redjeki

Rajungan (Portunus pelagicus) merupakan komoditas laut yang memiliki nilai ekonomis yang tinggi, dimana berbanding lurus dengan penangkapan yang terus meningkat. Tingkat pemanfaatan yang tidak mengindahkan ukuran dan kondisi rajungan dapat mempengaruhi struktur ukuran dan stok rajungan di suatu perairan. Penelitian ini bertujuan untuk mengetahui distribusi ukuran, hubungan lebar dan berat rajungan serta distribusi tingkat kematangan gonad (TKG) di perairan Betahwalang, Demak. Penelitian menggunakan metode survey dengan analisis yang bersifat deskriptif yang dilakukan secara “time-series”. Pengamatan sampel rajungan sebesar 10% dari hasil tangkapan yang didaratkan oleh setiap nelayan di pengepul rajungan.. Hasil dari penelitian ini menujukkan dari 3030 ekor rajungan yang diamati diketahui distribusi lebar karapas rajungan berkisar antara 35 – 185 mm dan kisaran berat sebesar 10 – 350 gram. Rajungan yang terdapat di perairan Betahwalang memiliki pertumbuhan yang bersifat allometrik positif pada rajungan jantan dan betina pada bulan Januari serta Februari.  Hasil nilai b sebesar 3,29 dan 3,08 (Januari & Februari) pada rajungan jantan. Nilai b sebesar 3,10 dan 3,15  pada rajungan betina (Januari & Februari) serta nilai b sebesar 3,14 pada keseluruhan rajungan. Sehingga diketahui pertumbuhan lebar karapas lebih cepat dibandingkan bobot rajungan. Sedangkan distribusi tingkat kematangan gonad rajungan betina adalah 21% pada TKG 1; 63% pada TKG 2; serta 16% pada TKG 3, dengan ukuran pertama kali matang gonad adalah 141,51 mm. Blue swimming crab (Portunus pelagicus) is a marine commodity has a high economic value , which is causing the crab catch to rise as well. The catch rate that does not consider the size and maturity of sea crab can affect the size structure and population stock of sea crab in waters. This study aims to determine the size distribution,the relationship of width and weight of Blue swimming crab and distribution of gonad maturity in Betahwalang, Demak. There’s a descriptive survey method used in this study with time-series observations. The sample size is about 10% of the total number landed crab from each fisherman. The results of this study showed that from 3030 crabs observed, the distribution of crab carapace width ranged from 35 – 185 mm and the weight range at 10 – 350 gram. The results showed the all crabs has a positive allometric on growth parameters. The value of  b 3,29 and 3,08 (January & February) in male blue swimming crab, 3.10 and 3.15 (January & February) on female sea crabs, and 3.14 on whole sea crabs. So it is known that the growth of carapid width is faster than the weight of crab. While the distribution of female crab gonad maturity level is 21% in level 1; 63% in level 2; and 16% in level 3, with the first size of mature gonad at 141,51 mm.


2013 ◽  
Vol 9 (2) ◽  
pp. 20121194 ◽  
Author(s):  
Matthew A. Wale ◽  
Stephen D. Simpson ◽  
Andrew N. Radford

Anthropogenic noise has fundamentally changed the acoustics of terrestrial and aquatic environments, and there is growing empirical evidence that even a single noise exposure can affect behaviour in a variety of vertebrate organisms. Here, we use controlled experiments to investigate how the physiology of a marine invertebrate, the shore crab ( Carcinus maenas ), is affected by both single and repeated exposure to ship-noise playback. Crabs experiencing ship-noise playback consumed more oxygen, indicating a higher metabolic rate and potentially greater stress, than those exposed to ambient-noise playback. The response to single ship-noise playback was size-dependent, with heavier crabs showing a stronger response than lighter individuals. Repeated exposure to ambient-noise playback led to increased oxygen consumption (probably due to handling stress), whereas repeated exposure to ship-noise playback produced no change in physiological response; explanations include the possibility that crabs exhibited a maximal response on first exposure to ship-noise playback, or that they habituated or become tolerant to it. These results highlight that invertebrates, like vertebrates, may also be susceptible to the detrimental impacts of anthropogenic noise and demonstrate the tractability for more detailed investigations into the effects of this pervasive global pollutant.


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