Gonadal Maturation Stages Research Articles

Some biological aspects of indian mackerel (Rastelliger kanagurta Cuvier, 1817) in Bali Strait waters

Indian mackerel (Rastrelliger kanagurta Cuvier, 1817) is a small pelagic fish species which is the main catch commodity in purse seine and jukung fleets in the Bali Strait waters. Sustainable management is urgently needed for indian mackerel populations in Bali Strait waters to remain sustainable fishery. The availability of basic information such as biological aspects is very important as a fundamental resource in the management of indian mackerel in Bali Strait waters. The aims of this study were to reveal several biological aspects of mackerel such as growth patterns, condition factors, sex ratio, and size at first maturity of indian mackerel in Bali Strait waters. Sampling was carried out in May-September 2018. Samples of fish were taken from purse seine and jukung fleets using trawl nets and gill nets. Fish sample was measured, weighed and dissected to observe the sex and the gonadal maturity stage. The total number of indian mackerel samples was 167 individuals. Mackerel in the Bali Strait waters has a positive allometric growth pattern with fish in good condition. The sex ratio was in an unbalanced condition with the number of male fish being more than the female fish. The size at first maturity was 19.34 cm for male fish and 19.76 cm for female fish.

Reproductive biology of endemic sailfin silversides fish Telmatherina antoniae Kottelat, 1991 in Matano Lake, South Sulawesi

Sailfin silversides (Telmatherina antoniae) is an endemic species from Matano Lake, South Sulawesi. This study aims to learn about sailfin silversides’ reproductive aspects including sex ratio, length at first maturity, gonad maturity stage, gonad maturity index, fecundity, and egg diameter. Fish samples were taken using multifilament nets from March 2018 until February 2019. A total of 1,792 individuals fish comprises 922 males and 870 females were captured during the study period. The sex ratio was found in a balanced condition with 1.06:1. Length at first maturity for males and females were 48.08-57.73 mm and 56.78-68.55 mm, respectively. Based on sailfin silversides’ gonad maturity stage and maturity index are thought to be year-round spawning with a peak spawning season around March. The reproductive potential of sailfin silversides fish is estimated to be 179–1,690 eggs. Based on the egg diameter distribution, the sailfin silversides fish is classified as a partial spawner.

Climate variable relate biological respond of tropical fish: A review from small scale fisheries in Sunda Strait

The issue of climate change is currently one of the crucial issues in fisheries management to ensure potential threats and their sustainability. Various approaches have been made, one of which is by looking at the influence of the population biology parameters such as the percentage of gonad maturity, the change from the length at first maturity (Lm50), and the first length of the first capture (Lc50)and growth rate (k). The research conducted from the Sunda Strait sea collected data from 2011, 2015, 2016, 2018, and 2019. The fish species whose biological data were analyzed were turmeric, kurisi and swanggi fish. The analysis performed was the size when 50 percent reached gonad maturity (Lm50), and the size of 50 percent of the fish caught (Lc50), the percentage of fish at the gonad maturity stage (TKG3-4). Annual trend analysis and linear regression determine the relationship between year temperature parameters and Lm, Lc, and the percentage of fish to be fully cooked gonads. The analysis results showed a fluctuation of Lm50, Lc50 in both male and female kurisi, kuniran and swanggi. However, there was no significant correlation between temperature and these parameters. These results indicate that the dynamics of Lm and Lm do not follow the trend of temperature changes. It is assumed that the effect of changes in Lm, Lc is more influenced by the intensity of the catch than the temperature in Sunda Strait.

Acceleration of gonadal maturity of female striped catfish, Pangasianodon hypophthalmus (Pisces, Pangasiidae) by irradiation to low-power soft-laser

This study was aimed to investigate the effects of red photodiode soft-laser irradiation on gonadal maturity and egg quality of female striped catfish, Pangasianodon hypophthalmus. Four female striped catfish (weighing 700–800 g) at stage I of gonadal maturation (for all treatments) were exposed four times (once a week) to different doses (0.2, 0.4, 0.6, and 0.8 J/cm2) of red photodiode soft-laser in the reproductive acupoint. Doses of 500 IU and 0.5 mL per kg body weight of human chorionic gonadotropin (hCG) and Ovaprim™, respectively were injected intramuscularly at week 4 (positive control), and no treatment (negative control). Finally, gonadal maturation stage (GMS), gonadosomatic index (GSI), hepatosomatic index (HSI), fecundity, and egg diameter were measured at week 5. The results showed that red photodiode soft-laser irradiation of 0.4 J/cm2 dose accelerated GMS IV at early week 3 (100 %) and increases GSI (3.42 %), HSI (1.26 %), fecundity (67,665 eggs/body weight), and egg diameter (1.01 mm) compared to the other treatments. Treatments of 0.2, 0.6, and 0.8 J/cm2 doses, and positive and negative controls only reached GMS III (75 %), III (25 %), I (100 %), II (25 %), and I (100 %), respectively. GSI values were 2.20 %, 1.47 %, 0.93 %, 0.44 %, and 0.42 %, respectively and HSI values were 1.07 %, 0.85 %, 0.7 7%, 0.66 %, and 0.53 %, respectively. Females irradiated with doses of 0.2 and 0.6 J/cm2 had fecundities of 38,822 and 29,530 eggs/body weight, respectively, and egg diameters of 0.88 and 0.29 mm, respectively. These results suggest that a red photodiode soft-laser irradiation accelerates gonadal maturity and improves egg quality in female striped catfish.

Biometric Relationship Between Growth Pattern and Biological Reproduction of a Living Fossil Benthic Brachiopods (Lingula anatina Lamarck, 1801) in Aceh Northern Shore

Brachiopods are a group of ancient marine invertebrates that are still found today, so they are known as "living-fossil". The purpose of this study was to determine reproductive biology through sex ratio approach, gonad maturity stages, body mass weight and growth pattern of L. anatina through size distribution approach, length-weight relationship, and condition factors. This research was conducted from April to December 2021, at the Aceh northern shore. The method used in this research is purposive sampling. The results showed that based on the morphological characteristics, only one species of brachiopods from the class Lingulata was found, namely Lingula anatina Lamarck, 1801. This species has an unequal sex ratio. Analysis of Body Mass Weight (BMW) and Gonado Somatic Index (GSI) shows an inverse relationship where the BMW value is lower than the GSI value. The condition factor of L. anatina also fluctuates every month, this is presumably due to availability of food in habitat. Gonad maturity stages of L. anatina at the locations of Syiah Kuala and Alue Naga were in spawning conditions (stages IV), especially for female L. anatina. These results indicate that the reproductive quality of L. anatina at the Aceh northern shore was maintained due to minimal exploitation from the surrounding community. Furthermore, the biometric (length – weight relationship) of L. anatina in the Aceh northern shore showing an isometric and negative allometric pattern. Basically, allometric growth is temporary, for example due to changes related to gonadal maturity, while isometric growth is a continuous change that is proportional.

Investigation of the physiological state of the Caspian common sprat in spring

The aim of the work was to assess the physiological state of the common sprat in the spring period near the Dagestan coast of the Caspian Sea. The study of individuals was carried out according to a set of biological indicators. The mass, length were determined, and the Fulton fatness coefficient was calculated. The stages of maturity of fish gonads were determined, the morpho-functional state of gonads and gills was assessed by histological methods. The content of total lipids and water-soluble protein were analyzed in the muscles. In March, females were predominantly marked III stage of gonad maturity, in April — IV stage of gonad maturity. In the spring period, diffuse resorption of mature oocytes was recorded at an average level of 27–28%. In males, IV–V, VI–V stages of testicular maturity were recorded. In April, a decrease in the content of total lipids and the Fulton fatness coefficient (p < 0.05) was registered relative to March, which is associated with the expenditure of the body’s energy on the maturation of gonads in portion-spawning common sprat. The concentration of water-soluble protein in sprat muscles in March and April was comparable. Local vascular disorders and the presence of mucosal cells were recorded in the structure of the gills. The revealed morphological disorders characterized the adaptive capabilities of the organ to the external influences of the habitat. According to the results of the studies conducted in the spring of 2022, the physiological condition of the Caspian common sprat was satisfactory. The results obtained are of great importance for predicting the development of the fishery for this species near the Dagestan coast of the Caspian Sea.

Reproductive Biology of <i>Chelon dumerili</i> (Steindachner, 1870) in Saloum Delta, Senegal (West Africa)

The present study evaluated the sex ratio, evolution of gonado-somatic index and stages of sexual maturity, condition factor and size of first sexual maturity of Chelon dumerili (Mugilidae) to determine its reproductive parameters. From June 2016 to May 2017, a total of 360 individuals of C. dumerili were sampled in Sangomar Marine Protected Area (MPA), In Saloum Delta, Senegal. The sex-ratio was significantly in favor of females (61.67%). Based on the monthly evolution of gonadal maturation stages and gonado-somatic index, the reproductive period of the species was determined to be from March to May. The condition factor varied between 0.60 and 0.88 with an average value of 0.84 ± 0.07. Male individuals of C. dumerili reached the size of first sexual maturity at a lower total length than females (23.6 cm and 24.5 cm respectively). Thus, for this species whose reproductive biology has not been well documented until now, knowledge of the reproductive parameters is essential to put in place measures for the sustainable management of the resource.

The Intra-Annual Variability of Immune System Organs and Lysozyme Content in Male Pike <i>Esox lucius</i> L.

The effect of the physiological state on the lysozyme concentration in the liver, kidney, spleen and serum, as well as the total amount of the enzyme in the organs, was studied in male pike Esox lucius L., 1758 under different conditions of the annual cycle. Multidirectional intra-annual dynamics of organ somatic indices and quantitative parameters of lysozyme in fish tissues and organs, depending on the temperature regime of the water body, was found. Despite significant changes in liver size and lysozyme concentration, the total amount of the enzyme in the organ, the lysozymic index, remained constant. A similar result was found in the spleen. When the influence of the temperature factor at low temperatures was minimized, the liver parameters changed to the opposite ones, while those in the kidney remained unchanged. Such a temperature regime did not affect the spleen parameters and the concentration of the enzyme in the serum. With significant differences between the liver and spleen in the enzyme concentration and size, their lysozymic indices were indicators of the same level. Stages of gonad maturity affected the liver index and the amount of lysozyme in the kidney, but the correlation of the kidney enzyme with maturity was not significant. The kidney lysozyme and the spleen parameters correlated with body mass without organs, although fish weight and length were not influencing factors. The size of the kidney, unlike the spleen, did not affect the enzyme in fish tissues. The liver and kidney enzyme concentrations and kidney lysozymic index were inversely correlated with liver size. A complex nature of the enzyme relationships in organs was revealed, at which the amount of lysozyme in one organ could affect the amount of the enzyme in the other. The relationship between the concentration of serum lysozyme and the morphophysiological parameters of fish under stable low temperature conditions in the water body was not found.

Reproductive and morphological analysis of the trairão Hoplias intermedius in the São Francisco River, downstream from a large reservoir.

Hoplias intermedius, of the Characiformes order and Erytrinidae family, is widely distributed across South America. This commercially interesting species can reach a length of 100 cm and a weight of 15-20 kg. To evaluate the reproductive biology of H.intermedius in the São Francisco River, Brazil, 154 males and 190 females were captured bi-monthly between September 2018 and August 2019 from the downstream regions of the Três Marias dam. Gillnets with differently sized meshes were deployed at distances of 34-54 km after the confluence with the Abaeté River (18°00'49″ S, 45°10'51″ W). Biometric data, gonadosomatic index (GSI), Fulton condition factor (K) and absolute fecundity (AF) were determined for each specimen. Gonad maturation stages and the spawning season were also established. The biometric data, GSI and K average values were relatively higher in females than in males. The reproductive peak for both sexes was reached around January/February. The mean AF was 4300.5 ± 1451.2 follicles per female. Fully developed vitellogenic follicles had a mean diameter of 1014.8 ± 250.7 μm, which is characteristic of fish with moderate fecundity. Fish of all maturation stages, from mature, spawned and spermed, occurred in all bimesters, indicating that this species reproduced throughout the year. The high frequency of spawning females throughout the year and the histological characteristics of spawned ovaries indicated that trairão H. intermedius' spawning type is partial.

Biological reproduction of mackerel scad, Decapterus macarellus (Cuvier, 1833) caught by purse-seine net in Majene Waters, West Sulawesi, Indonesia

Abstract. Tenriware, Nur M, Nasyrah AFA. 2023. Biological reproduction of mackerel scad, Decapterus macarellus (Cuvier, 1833) caught by purse-seine net in Majene Waters, West Sulawesi, Indonesia. Biodiversitas 24: 3012-3018. Mackerel scad, Decapterus macarellus Cuvier, 1833 is an economically important fish resource as an income source for fishermen in Majene waters, West Sulawesi. This study aims to determine some aspects of reproductive biology, including sex ratio, gonadal somatic index (GSI), gonad maturity stage (GMS), and the size at the first maturity. The sampling was carried out at the Fish Landing Sites in the Coastal Waters of Pangali-Ali Village, East Banggae District, Majene District, West Sulawesi Province, Indonesia. Each specimen was measured to the total length with digital calipers and body weight using a digital weighing scale. Initial sex assessment was noticed at the time of dissection, and gonadal maturity was also assessed. A total of 275 specimens consisting of 177 males and 98 females were obtained from April to July 2017. The result indicates that the sex ratio between males and females deviated from an expected 1:1: and was not balanced. This species spawns in April at the size of 173.4 mm and 168.6-178.3 mm for males and 189.1 mm or the range of 182.6-195.8 mm for females.

Reproductive Biology of Greenback Mullet, Planiliza subviridis (Valenciennes, 1836) from Segara Anakan Cilacap

Greenback Mullets (Planiliza subviridis) are a commercial commodity and are fished daily in the Segara Anakan Cilacap, although has not been overfished. Continuous and unregulated fishing might harm the Greenback Mullets population. Therefore, sustainable fisheries of this species are still needed. Reproductive biology is among the essential aspect that supports sustainable fisheries. This research aims to obtain information on the reproductive biology of Greenback Mullet in Segara Anakan Cilacap. The research used a survey method with a purposive random sampling technique. The observed parameters were the gonad maturity stage, gonad maturity index, and fecundity. The data were analyzed descriptively. The female individuals have gonad maturity stages III and IV, gonad maturity stage was 16.81±2.59 and 16.92±2.51, and fecundity was 37,208-183,661 and 38,468 - 272,835 in August and October, respectively. Conversely, male individuals have a low gonad maturity stage and gonad maturity index. Based on the data, Greenback Mullets in the Segara Anakan estuary have maximum gonad maturity stage, gonad maturity index, and fecundity in August and October, while in February they were in early gonadal development. These data are essential for sustainable fisheries management in the Segara Anakan estuary Cilacap, Central Java, especially for Planiliza subviridis.

VITELLOGENESIS ACTIVITY OF CHANNA MARULIOIDES, BLEEKER, 1851, IMPACT OF FOLICLE STIMULATING HORMONE AS REPRODUCTIVE DOMESTICATION

This study aims to determine the vitelogenesis activity by FSH hormone induction in the early stage of gonadal maturation. The treatament is a differences FSH dose with indicators of vitelogenesis activity were estradiol-17β levels in the blood, Hepatosomatic index (HSI) and Gonadosomatic Index (GSI). The study used a treatment A : Dose FSH at 1.0 ml/kg; B: Dose FSH at 1.25 ml/kg; C : Dose FSH at 1.5 ml/kg; control: nothing induction. The results showed that there was an effect of FSH dose on the estradiol 17β levels, HSI and GSI, there ongoing vitelogenesis activity. The trend of the GSI and HSI has a close correlation to levels of estradiol 17β, with the best dose of the hormone is 1.25 ml/kg resulting levels of esradiol 17β amounting to 63.35 pg / ml and the GSI and HSI are 3.45% and 1.48%. Furthermore, the best treatment successively resulted in increased levels of estradiol 17β, HSI and GSI in treatment C of 41.77 pg/ml, 1.48%, 3.24%; A : 28.01 pg / ml, 1.14 %, 3.42%;. FSH is suitable for reproductive domestication in Channa marulioides.

Some aspects of the control of the reproduction function in female sturgeon fishes

Two series of experiments on the effect of E-selenium on the reproductive function of sturgeons were conducted with different ways of introducing the drug into the body: through feed and injection. The effectiveness of the action of E-selenium was shown in two experiments. First, its ability to accelerate the process of maturation of oocytes was revealed due to the stimulation of generative metabolism and bringing it into line with the stages of the sexual cycle based on the biochemical parameters of the blood. An increase in the concentration in the blood by 1.4 times by the end of the 50-day experiment of total protein and beta-lipoproteins, which include ovovitelin (vitellogenin) during the period of vitellogenesis, as well as a moderate increase in haemoglobin concentration, indicates an increase in generative metabolism. It was noted that the metabolism of control fish was directed to somatic growth to a greater extent than that of experimental fish, as a result of which the average weight of females in control was 1.5 times higher than in the first series of experiments and weight of experimental fish was the same and increased by 6% in power in the second series. The role of the drug as a stabilizer of the physiological state of females, due to its high antioxidant properties, has been noted. When used, the existing signs of a stress state disappear, in contrast to the control fish in which they are detected: an increased cholesterol level, an erythrocyte sedimentation rate (ESR), and a decrease in haemoglobin concentration. The most significant effect from the use of the drug was obtained when the feed was irrigated with E-selenium, in which the number of mature fish after 50 days of the experiment was 2.7 times greater than in control, with a simultaneous halving of immature fish. In the case of the injection of females with this preparation, the number of fish at the IV stage of gonadal maturity in the experimental group after 50 days increased by 1.7 times. In the control group, on the contrary, it decreased by 1.2 times, with a constant proportion of females by the III stage of gonadal maturity.

Osmoregulation performance, condition factor, and gonad maturity of tilapia (Oreochromis niloticus) in Cengklik reservoir, Boyolali

Osmoregulation is a physiological adjustment mechanism of fish to environmental conditions. Fish growth performance will reduce when a large amount of energy is redirected for the osmoregulation process. The purpose of this study was to determine the osmotic work level (OWL), osmoregulation pattern, condition factor (K), gonad maturity stages (GMS) and analyze the relationship between OWL with condition factor and GMS of tilapia collected from three floating net cages in Cengklik reservoir, Boyolali. Samples were collected during March – April 2022 followed by some allometric measurements and regression analyses. The OWL of tilapia at the three cages ranged from 4 – 10 mOsm/L H2O; they performed a hyperosmotic osmoregulation pattern. The condition factor of male and female tilapia were1,86±0,21 and 1,89±0,18. GMS of both male and female tilapia was dominated by GMS IV with a fecundity of 9408±2092.54 eggs. OWL did not reveal a significant effect on condition factors or on the GMS of tilapia (p>0.05). Pearson correlation test showed a weak relationship between OWL with condition factors (r = 0,204) and tilapia GMS (r = -0,001). Therefore, tilapia uses less energy in osmotic work to produce good growth performance because it has more energy for growth, as indicated by the high condition factor (K>1) and domination by fish with GMS IV level of mature gonads.Keywords: Condition Factor; Gonad Maturity; Fish Cages; Oreochromis niloticus; Osmoregulation

Osmoregulation performance, condition factor, and gonad maturity of tilapia (Oreochromis niloticus) in Cengklik reservoir, Boyolali

Osmoregulation is a physiological adjustment mechanism of fish to environmental conditions. Fish growth performance will reduce when a large amount of energy is redirected for the osmoregulation process. The purpose of this study was to determine the osmotic work level (OWL), osmoregulation pattern, condition factor (K), gonad maturity stages (GMS) and analyze the relationship between OWL with condition factor and GMS of tilapia collected from three floating net cages in Cengklik reservoir, Boyolali. Samples were collected during March – April 2022 followed by some allometric measurements and regression analyses. The OWL of tilapia at the three cages ranged from 4 – 10 mOsm/L H2O; they performed a hyperosmotic osmoregulation pattern. The condition factor of male and female tilapia were1,86±0,21 and 1,89±0,18. GMS of both male and female tilapia was dominated by GMS IV with a fecundity of 9408±2092.54 eggs. OWL did not reveal a significant effect on condition factors or on the GMS of tilapia (p>0.05). Pearson correlation test showed a weak relationship between OWL with condition factors (r = 0,204) and tilapia GMS (r = -0,001). Therefore, tilapia uses less energy in osmotic work to produce good growth performance because it has more energy for growth, as indicated by the high condition factor (K>1) and domination by fish with GMS IV level of mature gonads.Keywords: Condition Factor; Gonad Maturity; Fish Cages; Oreochromis niloticus; Osmoregulation

Gametogenic Cycle of the Oysters Pinctada capensis (Sowerby III, 1890) and Saccostrea cucullata (Born, 1778) (Class Bivalvia) in Inhaca Island, Southern Mozambique: A Subsidy for Bivalve Culture in the Region

This study describes reproductive aspects of the Pinctada capensis (pearl oyster) and Saccostrea cucullata (rocky shore oyster) in Inhaca Island, southern Mozambique (Western Indian Ocean). Adult oysters were collected monthly over two years within seagrass banks for P. capensis and rocky shore habitats for S. cucullata. The animals were evaluated using biometric and histological analyses of the gonads. Of the total population, females were predominant among larger individuals (>55 mm) and males were more dominant among smaller individuals (<55 mm) for both species. The sex ratio was (1 M–1.5 F) for Pinctada capensis and (1 M–1.6 F) for Saccostrea cucullata. Five gonad maturation stages were identified: indifferent, developing I, developing II, ripe and spent. The size at first maturity was mm and 26.2 mm for pearl oysters females and males, respectively, whereas for rocky shore oysters was 32.8 and 28.3 mm for females and males, respectively. We conclude that the reproduction of S. cucullata and P. capensis occurs mainly in summer, with a short resting period in winter, when many oysters are in the indifferent stage. These results provide valuable information to fisheries for management of both species in the area.

Reproductive condition of the black-lip pearl oyster Pinctada margaritifera during the lunar phase.

This study analyzed the relationship between the lunar phase and the reproductive cycle of Pinctada margaritifera inhabiting Weno Island, Chuuk Lagoon, Micronesia. We measured indicators of maturity (gonadosomatic index [GSI]and sexual maturation-related genes) and investigated changes in the gonadal maturity stages (GMS) of P. margaritifera over lunar cycle. GSI was higher around the full moon. GMS of P. margaritifera were classified as the early gametogenesis stage, ripe and spawning stage, and spent and degenerating stage. A large percentage of oysters was observed in the ripe and spawning stage at the first quarter moon in female and the full moon in male as well as in the spent and degenerating stages at the third quarter moon in both sexes. In addition, the expression of doublesex- and mab-3-related transcription factor 2 (DMRT2) in the male P. margaritifera black-lip pearl oyster was the highest during the full and third quarter moon phases, whereas no difference in expression was observed with the lunar phase in females. In contrast, the expression of vitellogenin (VTG) was the highest in female P. margaritifera during the first and third quarters. No difference in expression was observed according to the lunar phase in males. The results suggest that the lunar phase directly affects the expression of sexually mature gonads in P. margaritifera black-lip pearl oyster.

Maturation, scale of gonad maturation stages and reproductive cycle of Pacific saffron cod Eleginus gracilis, Tilesius (Gadiformes, Gadidae)

Gonad size and weight dynamics and gonad-somatic index in the course of maturation have been analyzed, size structure and condition of oocytes of Pacific saffron cod at different stages of ovary matura- tion has been clarified. Reproductive cycle has been demonstrated, and scale of gonad maturation stages has provided.

Analysis of Molecular Genetic, Morphometric and Sexual Characteristics of the Beluga (Huso huso L., 1758) Grown in the Aquaculture of the Republic of Belarus

The subject of the study was genetic and phenotypic characteristics of Beluga (Huso huso (Linnaeus, 1758)) grown in the warm and cold-waters aquaculture at the “Selets” fish farm (the Republic of Belarus). Molecular-genetic analysis was performed using STR-markers and species-specific PCR revealed the absence of hybrid individuals in analyzed broodstock of (Huso huso L.). Affiliation of individuals to the Caspian population was established based on the sequence analysis of the 367 bp region of mitochondrial D-loop. Using six STR loci, the population structure was analysed. The population structure and gene pool of the only broodstock of (Huso huso L.) in Belarus was compared with domesticated (H. huso L.) from the Russian Federation. The analysis showed a lack of genetic variation and the heterozygote excess in Beluga from the Belarusian farm. Analysis of morphometric indicators revealed that the conditions in which the Beluga broodstock is kept at the fish farm “Selets” should be improved. Using ultrasound scanning, the following stages of gonad maturity were established: stages II, III and IV in males; II, II semi-fatty, II fatty, III and IV in females. The Beluga broodstock at the fish farm “Selets” is mainly represented by females (the females exceeded the males by 1.6 times in terms of their number).

Fishing impact of blue swimming crab (Portunus pelagicus) fishery on target in Lamongan Water, Northern Coast of Eastern Java Province

Blue swimming crab (Portunus pelagicus) is a high-value export commodity of fisheries to the international market. Thus, it promotes overfishing, reducing target stocks, and ecological impact on non-target biota. Fishers in Lamongan Regency use traps, trammel nets, and mini trawl (arad) to target the crabs. The fishing gears have different levels of selectivity. This study aims to evaluate the impact of crab fishing on target (P. pelagicus), particularly in the study area. The samples of blue swimming crab (BSC) were collected using the quota sampling method. The parameters of the crab catch (Portunus pelagicus) collected included carapace width, weight, sex, and gonad maturity stage (GMS). 1424 fishing vessels and 3598 fishers targeted the BSC in the Lamongan water. The result of this study showed that 93% of BSC catch was higher than the legal size from traps, 66% (arad), 89 % (trammel nets). The growth parameter of L∞ = 156.95 mm (for female) and L∞ = 182.22 mm (male), while K = 1.4 per year (for female) and K = 1.4 per year (male). The relationship between carapace width and weight of the male and female crabs was positive allometric growth. The LB-SPR parameter value was 23% which indicated that the crab resource stock in Lamongan waters was a ‘fully-moderately’ status, while the selectivity level indicated an ‘over-exploitation’ base on the E value = 0.69 (for female crab) and E = 0.72 (for male). This study proposes urgently reducing the fishing effort targeting BSC, particularly by the mini trawl (arad) and implementing a rebuilding stock program for the BSC.