Fishery Biology

Flying fish (Exocoetidae) is one important small pelagic fisheries commodity in border areas of Indonesia and Timor Leste. However, the data of population parameters in Ombai Strait are not yet known, which is important to inform unit stock management and sustainable fisheries. This study aimed to provide information about growth and mortality parameters, recruitment pattern, and exploitation rate of flying fish. Data collection was carried out during May 2018-June 2019 by measuring and observing the flying fish landed at the fish landing sites in Belu Indonesia and Bobonaro Timor Leste. Data analysis used the FAO-ICLARM Stock Assessment Tools (FiSAT) program. The results showed that the asymptotic length (L∞) was 330.5 mm, growth constant (K) was 0.99 per year, and growth performance indices (Ф) was 0.50. The natural mortality (M) was 0.92 per year, fishing mortality (F) was 0.12 per year, and total mortality (Z) was 1.04 per year. The highest recruitment occurs in May to September with peak season in June (14.82%) and September (15.16%). Exploitation rate (E) flying fish in the border area of Indonesia and Timor Leste in Ombai Strait is relatively low about 0.11 and still at a rational and sustainable utilization range (E < 0.5).

The exploitation level of skipjack tuna, Katsuwonus pelamis in Andaman waters is meagre compared to its total landings in India. As the population parameters of this species has not been attempted in these waters, an attempt has been made in this paper to estimate the population parameters of K. pelamis based on the length frequency data collected from local fishing boats operating from Junglighat Fishing Harbour, Port Blair, Andaman Islands from January to December 2014. A total of 704 specimens ranging from 16.5 to 71.0 cm fork length were taken for analysis. The parameters L ∞ , K and t 0 were 74.55 cm, 0.59/year and –0.21 respectively. The von Bertalanffy growth equation for K. pelamis is L t = 74.6[1 – e –0.59(t+0.214255) ]. The recruitment pattern was unimodal. The recruitment period was from July – October. The longevity of the species was calculated as 4.9 years. After 1 st , 2 nd , 3 rd and 4 th year the length attained by the species is 38.1, 54.4, 63.4 and 68.3 cm respectively. The mortality parameters were Z = 2.07, M = 0.93, F = 1.14 and exploitation ratio was 0.55. The virtual population analysis (VPA) for K. pelamis indicated that fishing mortality starts at 41–50 cm class interval and it continues henceforth and was maximum at 61–70 cm and decreased thereafter.

Information about reproductive biology is significantly needed in management of blue swimming crab (Portunus pelagicus) fishery. This research informs spatial and temporal sex ratio, gonadal development, gonado somatic index (GSI) and first size sexual maturity of male and female crab, as well as crab spawning season in Lasongko Bay, Southeast Sulawesi. Crab collection were conducted with gillnet in five different types of habitat. Gonadal development of crab was examined by their color and morphological characters. Sex ratio was analyzed of χ 2 test, and gonadal development proportion of male and female crabs were described. Gonado somatic index (GSI) among stations were analyzed by one-way ANOVA and followed by Tukey's test. Sex ratio of crabs spatially and temporally of generally did not differ significantly from 1:1. Gonad developments of male and female crab were varied spatially and temporally. GSI at every gonad development stage of male and female crabs generally was not significantly different among stations. GSI of male crab was smaller than the female crab. The first sexual maturity size of male and female crabs were 109.8 mm carapace width (CW) and 115.7 mm CW, respectively. The crab spawned in Lasongko Bay the whole year, and three peaks of spawning season were detected.

ABSTRAK
Ikan louhan tergolong jenis ikan hibrid (sehingga tidak dapat ditentukan nama ilmiahnya) dari famili Cichlidae yang terindikasi sebagai ikan asing invasif di Danau Matano. Keberadaan ikan tersebut di Danau Matano perlu dikaji dan dikendalikan untuk menjaga kelestarian keanekaragaman hayati jenis ikan endemik. Penelitian ini bertujuan untuk menganalisis pola peremajaan dan laju eksploitasi ikan louhan sebagai pendekatan dalam pengendalian ikan asing invasif di Danau Matano, Sulawesi Selatan. Analisis data dilakukan terhadap 2.931 ekor ikan louhan yang ditangkap menggunakan jaring insang percobaan berbagai ukuran mata jaring dilengkapi data enumerator secara bulanan pada bulan Februari hingga November 2016 dengan bantuan perangkat lunak FiSAT II. Hasil analisis menunjukkan bahwa pola pertumbuhan ikan louhan di Danau Matano bersifat alometrik positif. Pertumbuhan mengikuti persamaan L t =23,67[1-e 0,41(t+0,4281) ]. Umur maksimum (t max) mencapai 7,32 tahun dengan performa pertumbuhan (Ø') sebesar 2,36. Laju mortalitas total (Z) tahunan didapatkan sebesar 1,46 tahun-1. Laju mortalitas penangkapan tahunan (F = 0,38 tahun-1) lebih rendah daripada laju mortalitas alami tahunan (M = 1,08 tahun-1). Laju eksploitasi (E) ikan louhan di Danau Matano hanya sebesar 0,26 tahun-1 dimana menunjukkan bahwa upaya pemanfaatannya masih sangat rendah. Pola peremajaan terjadi dua kali dalam setahun, yaitu pada Mei (16,19%) dan Oktober (6,05%). Upaya pengendalian ikan louhan sebagai ikan invasif di Danau Matano perlu dilakukan pada saat puncak peremajaan tertinggi secara berkesinambungan disertai peningkatan laju eksploitasi e " 48% dari upaya yang ada, terutama pada April-Mei dan September-Oktober di daerah litoral perairan danau.
Kata Kunci: Ikan asing invasif; ikan louhan; laju eksploitasi; pengendalian; pola peremajaan; Danau Matano

ABSTRACT
Flowerhorn cichlid is classified as hybrid species (so that the scientific name can't be determined) from Cichlidae which indicated as invasive alien fish in Lake Matano. The existence of flowerhorn in Lake Matano need to be assessed and controlled to preserve the biodiversity of endemic fish species. This research aims to assess recruitment pattern and utlization status of flowerhorn cichlid for controlling of invasive alien species at Lake Matano, South Sulawesi. Data analysis was carried out on 2,931 flowerhorn Cichlid caught using experimental gillnets of various mesh sizes included enumerators data which recorded monthly from February to November 2016 using FiSAT II software. The analysis resulted the growth pattern of flowerhorn cichlid in Matano louhan Lake was positive allometric. The growth equation of flowerhorn cichlid was Lt=23.67[1-e 0,4(t+0.4281) ]. Longevity (t max) attained 7.32 years with growth performance (Ø') was 2.36. The annual total mortality rate (Z) obtained 1.46 years-1. The annual fishing mortality rate (F = 0.38 years-1) is lower than the annual natural mortality rate (M = 1.08 years-1). Exploitation rate (E) of flowerhorn cichlid in Lake Matano only 0.26 years-1, which was indicated under exploitation. Recruitment pattern occurs twice a year, in May (16.19%) and October (6.05%). The eradication efforts to control population of flowerhorn cichlid as invasive alien species in Lake Matano needs to be done at the peak of recruitment and also increased exploitation rate about e” 48% of existing efforts, especially on April-May and September-October in the littoral area of Lake Matano.
Keywords: Invasive alien species; flowerhorn cichlid; exploitation rate; controlling; recruitment pattern; utilization status; Lake Matano

Biodiversity of fin-fish and shell-fish species in three sections of Halda River, Bangladesh were investigated for two years from January 2007 to December 2008. Proportion of average daily catch (in number) was used to obtain the diversity indices. Simpson index of diversity (D) (0.54 - 0.66), Shannon index (H) (0.25 - 0.32) (re-scaled), and Evenness (E) (0.27 - 0.35) were calculated for fin fishes and shell fishes for 3 sections covering 39 km of the river. A total of 1017 catch samples of 34 different types of gear were analysed. Species richness (S) was observed to be 92 (83 fin-fish, 9 prawn), belonging to 14 orders, 37 families, and 71 genera including 3 exotic species over the studied area. Maximum number of species were recorded under the family Cyprinidae (19 species) followed by the family Gobiidae (11 species). Fin-fish species richness (FSR) in this study was 83, which was higher than earlier records. The actual total fin-fish and shell- fish species richness including the previous records was found to be 120 (106 fin-fish, 14 prawn), which is much higher than some larger river systems of Asia. Species richness was higher downstream (71 and 83 species) then mid (67 and 72 species), and upstream (61 and 69 species) for the years 2007 and 2008 respectively. ANOVA showed no significant difference between the populations of two years (F = 0.0025, df = 1 and 47, p > 0.05) and among the populations of three sections (F = 0.0008, df = 2 and 47, p > 0.05).Three critically-endangered, nine endangered, and eight vulnerable fish species (as in IUCN 2000) were observed in the population. Strong dominance was observed for Corica soborna (55.1 %) followed by Macrobrachium rosenbergii (19.2 %), Setipinna phasa (11.8 %), Glossogobius giuris (6.9 %), and Macrobrachium villosimanus (2 %). Three exotic species comprised less than 0.001 % of the population. Suggestions are provided for protection, conservation, and sustainable yield of the fish population of Halda River.

Proximate compositions of five economically-important fish species from Lake Victoria and Lake Tanganyika, Tanzania were determined using standard methods and procedures of the Association of the Analytical Chemists. Samples of Lates niloticus, Oreochromis niloticus, Rastrineobola argentea, Limnothrissa miodon and Stolothrissa tanganicae were collected during the dry and rainy seasons (December 2012 to March 2013) and (June to September, 2013). Protein contents (17.35-21.44 g/100 g) were significantly (p<0.05) higher in wet seasons and lower (16.13-19.77 g/100 g) during the dry season in all the species. Similarly, lipids contents were significantly (p<0.05) higher during the wet seasons (1.01 – 3.19 g/100 g) and lower (0.79-1.79 g/100 g) during the dry season in all the species, while carbohydrate (1.89-4.46 g/100 g) was significantly (p<0.05) higher during the dry season in all the species. The present study showed that these species are good sources of protein in desirable quantities for normal growth, development and as a remedy to nutritional and health related problems. High contents of protein and lipid during wet season make the fish species desirable for consumption during this period. These fish species are therefore recommended to diabetic consumers due to their low carbohydrate contents.

Natural reservoirs formed by river barrages are good repositories of fresh water fish in India. But, their quantity and diversity are threatened due to severe stress inflicted by the elements, responsible for anthropogenic environmental degradation. There is a pressing need to catalogue the ichthyofaunal assemblage and biodiversity in these man-made reservoirs to facilitate propagation of food fishes and alienation of predators. This paper elucidates the biodiversity of fish in Chulkinala reservoir in north Karnataka, which was not studied earlier. The data collected every month during

Nandus nandus (Ham) is a carnivorous fish. The fish is highly predatory and feeds primarily on finfish, shellfish and aquatic insects. The victual spectra trend of the gut contents of the fish has been studied through the four pronounced seasons of the year as ascertained by the index of preponderance. The relative length of gut reveals distinctly carnivorous behaviour. In males at maximum size range of 110-115 mm mean RLG is 1.03 whereas in females at size range of 110-115 mm, the RLG is only 0.903 indicating that females of the test species are more carnivorous than the males. The hepatosomatic index of the species depicts the feeding intensity of the test species. Lineament of feeding shows that the fish is a column feeder but is well competent to feed both at the surface as well as bottom level when food is supplied in the aquaria. The gill raker configuration reveal carnivorous pattern both in structure and number. The gill rakers are short and pointed backward.

Scales have numerous hidden details in their structures that contribute effectively to fish identification and classification. A traditional approach has been made to study the scale morphology of the Indian goatfish Parupeneus indicus using a stereomicroscope in tandem with a 12.2 megapixel Samsung ST500 digital camera in which digitized images were processed using Adobe Photoshop CS4 Extended software. Two specimens of fish sample of both sexes were described qualitatively and observed quantitatively. Thirty scales in every region were obtained for description and comparison. In describing the scales, several distinguishable characteristics were considered such as the type of the scale, overall scale shape, scale size, the shape of the posterior margin group of ctenii square, the position of the focus, circuli appearance, and the type of radii. Results of the study revealed that there are significant variations of shapes observed between male and female species. The presence of disrupted circuli, the same type of radii existing in each body regions in both sexes of the fish cannot be used to establish sexual dimorphism in P. indicus due to their similarities. The existence of an oblong scale shape is unique to males and that of a cycloid shape unique to females. Also, the variation of other scale shapes in region G where male has rectangular while female has triangular shapes but both have square scale shape and in region J where male has rectangular shape while female has square shape but both have triangular shape. Thus, these are significant indicator of sexual dimorphism between the sexes of P. indicus.

The present study reports the first occurrence of ectoparasite Pandarus cranchii infested on new host species " pelagic thresher shark, Alopias pelagicus " from the Andaman Sea. Total 11 specimens of P. cranchii were collected from the region of cloacal aperture and pelvic fins of a female A. pelagicus having a total length of 2650 mm and weighing 35 kg. It was caught by multifilament tuna longline vessel MFV Blue Marlin during July 2015 voyage as bycatch in the Andaman Sea. The sea surface temperature (SST) recorded at the sampling area was 28 °C. All the parasite specimens collected were found to be females with a size range of 4.3–6.5 mm (excluding egg sacs). The hanging –drop method was applied to examine the dissected appendages under the compound microscope and hand drawings were made to establish their identity. Detailed reports of P. cranchii from different geographical locations and diversity of the host species are also provided.

Coastal waters of Tangerang Regency has abundant in fish resource including pelagic, demersal, and reef fish. This study was conducted to assess fish biomass variability and of fish community structure in coastal waters of Tangerang Regency which can be used as a basis in determining alternatives for sustainable fish resource management. This research was conducted in June and August 2013 in three locations i.e., Kronjo, Cituis, and Tanjung Pasir. Primary data collected were fish weight per species. Fish biomass from each locations was obtained using swept area method using trawl. The results showed that Kronjo region contained the highest total average biomass of fish. Temporally, total average biomass of fish in August was higher than in June for Kronjo and Cituis. Meanwhile, the contrary occurred in Tanjung Pasir. This conditions occurred due to the high current and high wave in August than in June. In general, biomass of planktivorous was dominant during the study indicating overfishing lead to fishing down the food web in the Coastal waters of Tangerang Regency. Keywords: biomass, coastal waters of Tangerang Regency, spatial and temporal variability, swept area, over fishing. ABSTRAK Pesisir Kabupaten Tangerang merupakan salah satu pesisir yang memiliki sumber daya ikan yang cukup melimpah, baik ikan pelagis, demersal, maupun ikan karang. Tujuan dari penelitian ini adalah untuk mengkaji variasi biomassa komunitas ikan di pesisir Kabupaten Tangerang, sehingga dapat dijadikan dasar untuk upaya pengelolaan. Penelitian dilakukan pada bulan Juni dan Agustus 2013 di tiga lokasi, yaitu Kronjo, Cituis, dan Tanjung Pasir. Data primer yang dikumpulkan adalah biomassa ikan per jenis. Biomassa ikan dari masing-masing lokasi diperoleh melalui metode swept area dengan menggunakan alat tangkap trawl. Hasil yang diperoleh didapatkan bahwa lokasi Kronjo memiliki rata-rata biomassa total ikan paling tinggi di bandingkan Cituis dan Tanjung Pasir. Secara temporal, rata-rata biomassa total ikan pada bulan Agustus lebih tinggi dibandingkan bulan Juni untuk Kronjo dan Cituis, sedangkan sebaliknya untuk Tanjung Pasir. Hal ini disebabkan oleh tingginya arus dan tinggi gelombang pada bulan Agustus dibandingkan bulan Juni. Biomassa ikan planktivora dominan ter-tangkap selama penelitian. Hal tersebut mengindikasikan terjadinya tangkapan lebih pada ikan-ikan karnivora yang dapat mengarah pada fishing down the food web di pesisir Kabupaten Tangerang. Kata kunci: biomassa, Pesisir Tangerang, variasi spasial dan temporal, penyapuan area, tangkap lebih.

A comparative study of morphometric characteristics of rohu (Labeo rohita) and Jayanti rohu was
conducted on the farmed fish specimen of College of Fisheries, Pantnagar, Uttarakhand. The descriptive
statistical parameters and correlation coefficient (r) were analysed with independent variable (total length)
and dependent variable (other morphometric parameters). The maximum correlation coefficient of average
total length was obtained with fork length (0.977) and with standard length (0.979) in Jayanti rohu and
rohu respectively. Minimum correlation coefficient, 0.356 in body depth-total length (BD-TL) and 0.424 in
head length (HL -TL) was reported in rohu and Jayanti rohu respectively. Correlation coefficient in Jayanti
rohu (BD-TL) is higher than rohu (0.778). The results reveal that morphometric parameters are
significantly correlated to total length except caudal length in Jayanti rohu and body depth in rohu,
respectively which signifies more body convexity of Jayanti rohu in comparison to rohu.

This document analyses some population parameters of Yellowfin Tuna (Thunnus albacares) taken by drift gillnet operation from southern part of Iranian coast in the Oman Sea during 2007 to 2009. A total of 9,345 specimens of T. albacares were sampled in the size range of 37 cm to 172 cm fork length (FL). The mean length was estimated to be 86.12 cm. There was influence from seasonal variation on the length distribution of individuals, and it showed a tendency of gradual increase in the model length with the fishing season. The temporal change in length distribution is more likely to be an indication of feeding migration of medium-sized Yellowfin Tuna from the western Indian Ocean into the Oman Sea during January to June. The statistical analysis of lengthweight relationship was achieved by sex. The electronic package &quot;ELEFAN I&quot; was chosen for describing the species&#39; von Bertalanffy growth equation; parameters were L∞= 183.3 cm, K= 0.45 year-1, and t0= -0.184 year. Natur...

Mortality parameter and exploitation rate are important factors in the assessment of fish resource stocks for sustainable management. Information about mortality parameter and exploitation rate of mackerel tuna in the Ombai Strait waters is still lacking. This research was
conducted to provide information about mortality parameter and exploitation rate. Data collection was carried out during May - August 2018 by measuring and observing the mackerel tuna landed at the Atapupu Fish Landing Site. Data analysis uses the FAO-ICLARM Stock
Assessment Tools (FiSAT) program. The results showed that the Fork Length (FL) range was 163 - 450 mm and the average length was 249.2 mm. The range of weight between 47 - 1200 grams with average 226.6 grams. The total mortality (Z) was 1.376 per year, natural mortality
(M) was 0.695 per year and fishing mortality (F) was 0.681 per year. Exploitation rate (E) of mackerel tuna in the Ombai Strait waters was 0.495 per year and still at a rational and sustainable utilization range (E < 0.5).

Understanding the processes driving species distributions is a key question in ecology, yet obtaining pertinent data for many species can be challenging. Tag-recapture data from voluntary recreational fisheries programmes is an undervalued citizen science data resource and can
provide valuable observation records for data-poor species. Here, we highlight the utility of such data by compiling four tag-recapture data-
sets (n = 20 878 tags) to describe the movements and distribution of a piscivorous predator, tailor Pomatomus saltatrix, with respect to their
environment. We compared species distribution models that explored a trade-off between temporal duration and spatial extent. Both models
revealed sea surface temperature (SST) was an important factor in describing the distribution and density of tailor. However, the model with
broader spatial extent indicated a non-linear response to SST, peaking at 21.5 C, while the model with temporal longevity showed a linear
SST response. This disjunct showcases the importance of building models across an adequate geographic extent to ensure covariate responses are not truncated. This is the first study to comprehensively describe the distribution and migrations of adult tailor across their eastern Australian distribution. The results are discussed in light of ocean warming along eastern Australia, and the subsequent implications for using tag-recapture data in fisheries management.

This studies analyses some of the population parameters of Bigeye snapper (Lutjanus lutjanus, Bloch 1790) off Madras coast along southeast coast of India based on length-frequency data. The samples were collected from the trawl catches of the vessel M.F.V. Samudrika (OAL: 28.8m, GRT: 151T, BHP: 650) from January 2007 to June 2009 between the area Lat.12°30' N to 13° 32' N and Long. 80° 12'E to 80°30'E. A total of 858 specimens in the length range of 38-203 mm total length (TL) were analysed with the help of electronic package FiSAT. The parameters L∞ and K were 213.2 mm ,0.28/year. The von Bertalanffy (1938) growth equation for Lutjanus lutjanus is L t = 213.2[1-e-0.28(t-t 0) ]. The recruitment pattern is unimodal and the period was from February –May with peak during March. The longevity of the species was calculated as 7years. After 1 st , 2 nd , 3 rd , 4 th ,5 th , 6 th and 7 th year the length attained by the species is 51.2, 91.7, 121.5, 144.9, 159.9, 172.7 and 183.3 mm respectively. The mortality parameters were Z=0.71, M =0.44, F=10.27 and the exploitation ratio was 0.38. The virtual population analysis(VPA) for Lutjanus lutjanus indicated that the natural morality due to natural cause was upto 138mm length, however the fishing pressure was observed at 143 mm size and it increased thereafter.

Ancient DNA (aDNA) approaches have been successfully used to infer the long-term impacts of climate change, domestication, and human exploitation in a range of terrestrial species. Nonetheless, studies investigating such impacts using aDNA in marine species are rare. Atlantic cod ( Gadus morhua ), is an economically important species that has experienced dramatic census population declines during the last century. Here, we investigated 48 ancient mitogenomes from historical specimens obtained from a range of archeological excavations in northern Europe dated up to 6,500 BCE. We compare these mitogenomes to those of 496 modern conspecifics sampled across the North Atlantic Ocean and adjacent seas. Our results confirm earlier observations of high levels of mitogenomic variation and a lack of mutation-drift equilibrium—suggestive of population expansion. Furthermore, our temporal comparison yields no evidence of measurable mitogenomic changes through time. Instead, our results indicate that mitogenomic variation in Atlantic cod reflects past demographic processes driven by major historical events (such as oscillations in sea level) and subsequent gene flow rather than contemporary fluctuations in stock abundance. Our results indicate that historical and contemporaneous anthropogenic pressures such as commercial fisheries have had little impact on mitogenomic diversity in a wide-spread marine species with high gene flow such as Atlantic cod. These observations do not contradict evidence that overfishing has had negative consequences for the abundance of Atlantic cod and the importance of genetic variation in implementing conservation strategies. Instead, these observations imply that any measures toward the demographic recovery of Atlantic cod in the eastern Atlantic, will not be constrained by recent loss of historical mitogenomic variation.

Blue Swimming crab (Portunus pelagicus) is one of important fishery in Indonesia that captured nearshore on the bottom of the sea. There has been a significant water contamination on the Jakarta bay and the fishery are reported to be effected. Many heavy metals and other contaminants are introduced into the waters, sediments, and fishery that living in the bay. Heavy metals such as Pb, Cd, Hg and As are the most lethal contaminants and found in Jakarta Bay. This study aims to determine the effect of heavy metals contaminants to the blue swimming crab morphometric, body organs and population structure of blue swimming crabs in Jakarta bay, which compared to the study in healthier environment in Madura island. The results of this study showed that 1) The morphometric parameter of blue swimming crab population in Jakarta and Madura are significantly different. 2) The internal organ of the blue swimming crab (hepatopancreas, gonad and gill) in Jakarta bay are also significantly different than in Madura. The histological analysis are confirmed some abnormal indication of the internal body of the blue swimming crab in Jakarta bay.3) Some population parameters of the blue swimming crab in jakarta bay are significantly different than in Madura island. The fishery structure in Jakarta bay showed the size of first maturity of the crabs is relatively smaller than in Madura and other area of Inodonesia. The fishery mangament based on spatial area management is recommended to apply in different area of Indonesia.

Food and feeding habits of white bream, Blicca bjoerkna specimens captured from Lake Ladik between November 2009 and October 2010 were investigated with respect to length groups and seasons. Stomach contents of 207 individuals ranging in size from 115 to 243 mm fork length were analyzed and 23.67% were empty. There was a seasonal variation in the feeding intensity of this species. The spring and summer feeding intensity were quite lower than other seasons. The food items in stomach showed a wide spectrum, ranging from phytoplankton, macrophytes, zooplankton to aquatic insects. Therefore, white bream displayed an omnivorous feeding. The relative importance index (RII%) indicated that Bosmina, Macrophytes, Chironomid larvae, Melosira, Navicula, Cymbella and Cyclopoid copepod were the most importance food items of white bream. The feeding strategy indicated that white bream plays an accelerator role in eutrophication. According to the Schoener’s overlap index values, there was a high degree of consumed food overlap between spring-autumn (Cxy = 0.78095) and summer-winter (Cxy = 0.92035).

The freshwater gobi, Glossogobius giuris (Hamilton-Buchanan, 1822)
(Gobiidae: Perciformes) is an important freshwater fish species in Bangladesh. The
age and growth of this species, collected from the river Titas, Brahmanbaria, were
studied with transverse sections of otoliths. The otolith’s opaque zones that are
formed every year were the annual rings. The growth of this species was rapid
during the first two years, reaching 18.5 cm in total length. Most of the specimens
were 1-2 years old and accounted for 90% in total. The maximum age recorded
was five years with 19.5 cm in total length. The von Bertalanffy growth parameters
L∞ and K for this species were 19.58 cm and 1.36/year, respectively. The study
indicated that the age and growth of G. giuris can be determined using its
sectioned otolith.
Key words: Glossogobius giuris, otolith, age and growth.

The present study was undertaken to trace precisely the spawning period of an important ornamental fish species, Brachydanio rerio. Gonadosomatic index (GSI) expresses the relative change in gonad weight to the percentage of body weight. In the present study two peaks are observed in the GSI of Brachydanio rerio, first peak is observed in the month of June and the second in the month of October.

The present study aims to determine whether the rate of exploitation for grouper stocks is in accordance with their biological attributes (growth and mortality). The results showed that Plectropomus maculatus and P. oligocanthus taken from Cenderawasih Bay National Park (CBNP) were in the size category of actively productive spawning phase. P. maculatus could reach a maximum length (L1) of 484.05 mm and growth rate (K) of 0.34 per year. P. oligocanthus was capable of reaching L1 of 481.95 mm and K of 0.66 per year. Estimation of total mortality (Z) for P. maculatus was 0.988 and P Oligocanthus was 2.056. In addition, fishing mortality (F) for P. maculatus and P. oligocanthus were 0.564 and 0.399 respectively. Based on the estimated mortality values, it was estimated that the exploitation rate (E) of P. maculatus was 0.570, and P. oligocanthus was 0.681. Management settings for P. maculatus and P. oligocanthus can be separately based on the species so that the fishing can be sustainable. The introduction of minimum size limits for fish caught can be applied as a protection from hook and hand line fishing activities in CBNP. Introduction The high demand for groupers has led to an increase in the sale value of the fish and has brought about substantially high profits for trading business of this commodities. As consequently, this has been pushing an increase in fishing intensity for groupers and become primary fishing target of fishery in coral reef areas. Groupers are caught in the wild by traditional fishermen using hook and lines, and fish traps. High fishing intensity brings consequences to grouper sustainability. That is, grouper population experiences high fishing pressure. In some regions of Indonesia, it has been reported that total catch of groupers has decreased and the stock has been overexploited (Sadovy, 2005). Fishing continuously on large sizes of fish or spawning fish stock could reduce the genetic characteristics and could change fish shape and behavior. The genetic diversity of the population would be likely affected thereby reducing its resilience in confronting with environmental change and variability (Vrijenhoek, 1998). Hurtado et al. (2005) and Nelson (2007) note that populations experiencing high exploitation is characterized by a change in the fish size composition, which is dominated by smaller sizes. This would significantly affect reproductive outcome since small fish size has less production potential than the large fish size. Large-scale of exploitation could cause structural changes in the fish. Sanchez (2000) suggests that in overfishing state of fish stock, the fish population are dominated by small sizes or young fish since fishermen tend to catch large size of fish. Aside from fishing activities, the production of groupers in nature is strongly influenced by geomorphology and hydrographic characteristics of water; these affect the overall productivity and spawning aggregation (Coleman et al., 2011). Fish spawning areas of groupers, nowadays, become the target fishing areas by fisher-men in order to increase their catch per unit effort. Although fisheries production increases in short term, such fishing practices in long term are likely to lessen fishery production as a result of the damage of spawning habitat, the decrease in reproductive output and the changes in sex ratio (Heyman

Sodium cyanide is a common environmental pollutant which is mainly used in many industries such as mining, electroplating, steel manufacturing, pharmaceutical production and other specialized applications including dyes and agricultural products. It enters aquatic environment through effluents from these industries. Static renewal bioassay test has been conducted to determine LC, of sodium cyanide on indigenous freshwater carp, Labeo rohita. The behavioural pattern and oxygen consumption were observed in fish at both lethal and sub lethal concentrations. Labeo rohita in toxic media exhibited irregular and erratic swimming movements, hyper excitability, loss of equilibrium and shrinking to the bottom, which may be due to inhibition of cytochrome C oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system resulting in respiratory arrest and death. Decrease in oxygen consumption was observed at both lethal a...