Distribution and abundance of the tiger prawns Penaeus esculentus and P. semisulcatus in the north-western Gulf of Carpentaria, Australia

1987 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
IF Somers ◽  
PJ Crocos ◽  
BJ Hill
Keyword(s):  
Water Temperature ◽  
Individual Species ◽  
Northern Coast ◽  
Catch Per Unit Effort ◽  
Nursery Areas ◽  
The North ◽  
Juvenile Abundance ◽  
Tiger Prawn ◽  
North Western ◽  
Trawl Surveys

Trawl surveys in the north-western Gulf of Carpentaria were carried out each lunar month from August 1983 to March 1985 to assess the temporal and spatial distribution and abundance of P. esculentus and P. semisulcatus. The information obtained was then compared with that from fishermen's logbooks. Water temperature and salinity were monitored during the study and their possible influence on the distributions has been inferred. The distributions of juveniles of less than 20 mm carapace length indicated that, for both tiger prawn species, the main nursery areas in the region were in Blue Mud Bay and in the bays along the northern coast of Groote Eylandt. Although the two species shared the same nursery areas, the juveniles were concentrated in different parts of Blue Mud Bay and were most abundant at different times. Catches of juvenile P. esculentus increased substantially in October and peaked in November, whereas catches of juvenile P. semisulcatus increased in November and peaked in January. Catches of both species showed a secondary peak in March 1984, coincident with the heaviest monthly rainfall of the summer monsoon season. The distribution of larger prawns showed spatial separation of the two species in the offshore fishery. The monthly pattern of the catch-per-unit-effort (CPUE) of the two tiger prawn species combined was similar to that obtained from fishermen's logbooks; the logbook data are therefore generally reliable. Monthly CPUE from the trawl surveys for the individual species showed distinct peaks in late summer, which were apparently related to recruitment of small prawns into the fishery. CPUE for P. semisulcatus peaked in February and April (juvenile abundance had peaked in January and March); CPUE for P. esculentus peaked in January and May (juvenile abundance had peaked in November and March). However, a distinct CPUE peak in spring (August/September) for P. semisulcatus could not be related to a previous peak in juvenile abundance; this was presumably a result of an increase in catchability. Although there was evidence linking changes in the catchability of P. semisulcatus to changes in water temperature, a similar link was not as evident for P. esculentus.

Exploitation and movements of yellowfin tuna (Thunnus albacares) and bigeye tuna (T. obesus) tagged in the north-western Coral Sea

1998 ◽  
Vol 49 (6) ◽  
pp. 475 ◽  
Author(s):  
John Hampton ◽  
John Gunn
Keyword(s):  
Seasonal Pattern ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
Bigeye Tuna ◽  
Catch Per Unit Effort ◽  
The North ◽  
Coral Sea ◽  
Release Area ◽  
Seasonal Signal ◽  
North Western

Yellowfin tuna (Thunnus albacares) and bigeye tuna (T. obesus) were tagged and released in the north-western Coral Sea off northern Queensland in 1991 and 1992. Over the next five years, recaptures were reported by Australian longline vessels based in Cairns and fishing in the release area, and by industrial tuna fleets fishing in the adjacent western Pacific region, thus demonstrating clear links between the tuna stocks in these areas. Some southerly movements of yellowfin, in particular, further suggested links with stocks supporting the longline fishery in the south-eastern Australian Fishing Zone. Bigeye tuna tag returns and catch per unit effort by Cairns-based longliners showed a strong seasonal signal, peaking in mid year. Yellowfin tag-return data displayed a similar, but weaker, seasonal pattern. The data were analysed by use of tag-attrition models with seasonally variable catchability and with two assumptions regarding changes in targeting of the two species by longliners during the study. Under both assumptions, the local exploitation rates for yellowfin are low: about 0.07 in 1996. For bigeye, the local exploitation rate in 1996 may have been as high as 0.30, warranting a cautious approach to further fishery expansion in this area.

Population ecology of the grooved tiger prawn, Penaeus semisulcatus, in the north-western Gulf of Carpentaria, Australia: growth, movement, age structure and infestation by the bopyrid parasite Epipenaeon ingens

1991 ◽  
Vol 42 (4) ◽  
pp. 349 ◽  
Author(s):  
IF Somers ◽  
GP Kirkwood
Keyword(s):  
Sex Ratio ◽  
Age Structure ◽  
Frequency Data ◽  
Length Frequency ◽  
The North ◽  
Penaeus Semisulcatus ◽  
Growth Movement ◽  
North Western ◽  
Length Frequency Data ◽  
Trawl Surveys

Concurrent trawl surveys and tag-recapture studies carried out in the north-western Gulf of Carpentaria between August 1983 and March 1985 provided a detailed description of the growth, movement and age structure of the population of grooved tiger prawns, Penaeus semisulcatus. Growth curves based on the tag-recapture data were used to interpret the length-frequency data collected from the trawl surveys and to determine the number of year classes present. The length-frequency data pertaining to the 1984 year class provided the basis for an estimate of the longevity of the species and a description of the offshore movement patterns. The effect of infestation by the bopyrid parasite Epipenaeon ingens on growth and movement was also examined. Individuals of P. semisulcatus may live for about 2 years, but in the north-western Gulf of Carpentaria very few survive beyond 18 months. Subadults recruit to the offshore fishing grounds during summer and autumn (November-March) at sizes between 20 and 25 mm carapace length (CL) (between 4 and 6 months). By 18 months of age, males reach a size of about 39 mm CL and females about 50 mm CL. The growth rates of both sexes are affected by the presence of E. ingens: males grow faster and larger, the females slower and smaller, with both sexes attaining a size of around 43 mm CL by 18 months of age. The recruiting year class continues to disperse offshore during autumn (from March to May) in such a way that by winter (June and July), although highest abundance is in depths of 35-40 m, the population extends well beyond the commercial fishery into depths greater than 50 m. Although prawns infested with E. ingens show a similar offshore movement, they do not venture beyond depths greater than about 30 m. The sex ratio within the year class remains at around 1 : 1 from the time of recruitment to about 1 year of age. Thereafter, the percentage of females declines steadily; by about 18 months of age very few prawns remain in the population, and of these only about 25% are female. In contrast, the sex ratio for prawns infested with E. ingens remains at about 1 : 1 throughout.

scholarly journals KARAKTERISTIK PERIKANAN TERI (ENGRAULIDAE) DI PANTAI UTARA JAWA-MADURA

2021 ◽  
Vol 26 (3) ◽  
pp. 135
Author(s):  
ACHMAD ZAMRONI ◽  
Heri Widiyastuti ◽  
Suwarso Suwarso
Keyword(s):  
North Coast ◽  
Small Scale ◽  
Fishing Gear ◽  
Eastern Region ◽  
Northern Coast ◽  
Catch Per Unit Effort ◽  
Fishing Season ◽  
The North ◽  
Fishing Vessels ◽  
Landing Sites

Perikanan teri berkembang sangat pesat khususnya di perairan utara Jawa Madura pada tahun terakhir ini. Kajian tentang karakteristik perikanan teri (Engraulidae) di sepanjang pantai utara Jawa-Madura dilaksanakan pada tahun 2017-2018, meliputi sebaran usaha perikanan, tipe armada-alat penangkapan ikan, aspek operasional penangkapan, hasil tangkapan-kelimpahan dan musim penangkapan ikan teri. Pengumpulan data pendaratan ikan teri dilakukan melalui survey di 11 lokasi pendaratan ikan. Hasil penelitian menunjukkan terdapat 12 lokasi tempat pendaratan utama ikan teri di sepanjang pantai utara (pantura) Jawa dan Madura. Dua jenis alat dominan digunakan untuk penangkapan teri adalah pukat cincin dan payang; perikanan bersifat skala kecil, melakukan trip harian, dengan armada kapal penangkap berukuran dibawah 20 GT. Jaring umumnya menggunakan waring dengan mata jaring kecil (3/8 inch) di bagian kantong. Daerah penangkapan di perairan pantai yang dangkal, dekat dengan basis perikanan. Musim penangkapan ikan teri bervariasi, di wilayah bagian barat (Pulolampes, Larangan, Morodemak) berlangsung sekitar musim timur/tenggara (Mei Juli), sedangkan di wilayah bagian timur berlangsung pada awal musim timur dan berjalan cukup lama hingga bulan November (musim peralihan 2). Hasil tangkapan per unit upaya (CPUE, sebagai indek kelimpahan) diduga makin ke arah timur semakin rendah namun disertai musim penangkapan ikan lebih lama. Anchovy fishery has grown rapidly, especially in the northern waters of Java-Madura in the last year. The study on the characteristics of the anchovy fishery (Engraulidae) along the northern coast of Java-Madura was carried out in 2017-2018, covering the distribution of fisheries effort, types of fishing gear, operational aspects of fishing, catch-abundance and fishing season. The collection of anchovy landing data was carried out through a survey at 11 fish landing sites. The results showed that there were 12 main anchovy landing sites along the north coast (pantura) of Java and Madura. Two types of dominant fishing gear used for anchovies are purse seine and payang; Fisheries are small-scale, undertaking daily trips, with a fleet of fishing vessels under 20 GT. The nets generally use “waring” with small mesh (3/8 inch) in the codend. Fishing area in shallow coastal waters, close to the fishing base. The fishing season for anchovy varies, in the western region (Pulolampes, Larangan, Morodemak) it takes place around the east / southeast season (May-July), while in the eastern region it takes place at the beginning of the eastern season and lasts quite a long time until November (transition season 2) . The catch per unit effort (CPUE, as an abundance index) is thought to be getting lower eastward but accompanied by a longer fishing season.

Impacts of spatial scales of fisheries and environmental data on catch per unit effort standardisation

2009 ◽  
Vol 60 (12) ◽  
pp. 1273 ◽  
Author(s):  
Siquan Tian ◽  
Yong Chen ◽  
Xinjun Chen ◽  
Liuxiong Xu ◽  
Xiaojie Dai
Keyword(s):  
Spatial Scale ◽  
Stock Assessment ◽  
Spatial Scales ◽  
Additive Models ◽  
Environmental Data ◽  
Catch Per Unit Effort ◽  
The North ◽  
Unit Effort ◽  
Data Collection And Analysis ◽  
North Western

Spatial scale is an important factor that needs to be considered in data collection and analysis in ecological studies. Studies focusing on the quantitative evaluation of impacts of spatial scales are, however, limited in fisheries. Using the Chinese squid-jigging fishery in the north-western Pacific Ocean as an example, we evaluated impacts of spatial scale used in grouping fisheries and environmental data on the standardisation of fisheries catch per unit effort (CPUE). We developed 18 scenarios of different spatial scales with a combination of three latitudinal levels (0.5°, 1° and 2°) and six longitudinal levels (0.5°, 1°, 2°, 3°, 4° and 5°) to aggregate the data. We then applied generalised additive models to analyse the 18 scenarios of data for the CPUE standardisation, and quantified differences among the scenarios. This study shows that longitudinal and latitudinal spatial scale and size of the spatial area for data aggregation can greatly influence the standardisation of CPUE. We recommend that similar studies be undertaken whenever possible to evaluate the roles of spatial scales and to identify the optimal spatial scale for data aggregations in the standardisation of CPUE and fisheries stock assessment.

Reproductive dynamics of the grooved tiger prawn, Penaeus semisulcatus, in the north-western Gulf of Carpentaria, Australia

1987 ◽  
Vol 38 (1) ◽  
pp. 79 ◽  
Author(s):  
PJ Crocos
Keyword(s):  
Egg Production ◽  
Fishing Effort ◽  
Minimum Size ◽  
Limited Area ◽  
The North ◽  
Penaeus Semisulcatus ◽  
Spawning Stock ◽  
Tiger Prawn ◽  
A Minor ◽  
North Western

The reproductive cycle of female P. semisulcatus was investigated in the region north of Groote Eylandt in the Gulf of Carpentaria from August 1983 to March 1985. Approximately 1750 trawls were carried out over 21 monthly sampling cruises, and 13 748 females were examined. The minimum size at maturity was 29 mm carapace length (CL), and 50% of the population were mature at 39 mm CL. The proportion of females which had mated increased sharply above 34 mm CL with a maximum of 80% of females inseminated in the size range 38-54 mm CL. An index of population egg production, calculated from female abundance, the proportion of females spawning and fecundity according to size, was used as an indicator of reproductive output. Egg production was markedly seasonal, with a major spawning peak in August-September, and a minor one in February. Spawning occurred in a limited area within rhe study area. The spawning stock of P. semisulcatus is likely to be vulnerable to fishing pressure because the area and time of major spawning coincides with the major fishing effort in the region.

Approaches to the assessment and management of multispecies skate and ray fisheries using the Falkland Islands fishery as an example

2000 ◽  
Vol 57 (2) ◽  
pp. 429-440 ◽  
Author(s):  
D J Agnew ◽  
C P Nolan ◽  
J R Beddington ◽  
R Baranowski
Keyword(s):  
Individual Species ◽  
Falkland Islands ◽  
Catch Per Unit Effort ◽  
Likelihood Methods ◽  
The North ◽  
Production Models ◽  
Linear Modelling ◽  
Maximum Likelihood Methods ◽  
Modelling Techniques ◽  
Generalised Linear Modelling

Eleven rajid species are taken around the Falkland Islands, with four species, Bathyraja griseocauda, Bathyraja albomaculata, Bathyraja brachyurops, and Raja flavirostris dominating commercial catches and generally occurring together. Catch limits for individual species are not used in management because species are not separated in the catch or reported separately. The catch per unit effort for the mixed rajid assemblage was standardised using generalised linear modelling techniques, and two production models were used to estimate stock size and sustainable yield. Maximum likelihood methods were used to demonstrate that there are two distinct rajid communities, one to the north and one to the south of the Falkland Islands, which have different sustainable yields. Changes in species composition over the 10-year course of the fishery confirm theoretical expectations that the larger, later-maturing B. griseocauda is being replaced in catches by the smaller, earlier-maturing B. albomaculata and B. brachyurops. These changes in composition were evident after only 6 years of directed fishing. The current fishery to the north of the Falkland Islands appears to be stable at an annual catch of about 3000 t, which is between 6.5 and 7.6% of the estimated pre-exploitation biomass.

scholarly journals The Athenian Red-Figure Pottery Found in Nikonion During Excavations of 2007-2012

2018 ◽  
Vol 21 ◽  
pp. 89-117
Author(s):  
Inga Głuszek
Keyword(s):  
Residential Building ◽  
The Black Sea ◽  
Northern Coast ◽  
City Development ◽  
Ancient Greek ◽  
Short Introduction ◽  
The North ◽  
State Of Research ◽  
The City ◽  
North Western

The article discusses fragments of the Athenian red-figure pottery discovered during excavations in Nikonion, an ancient Greek colony founded on the northern coast of the Black Sea, at the end of the 6th century BC. The collection of Athenian pottery finds at this site is very diverse in terms of technique, style and phase of production. In a short introduction to the article the state of research on the finds of Athenian red–figure pottery from the site is presented, but the main focus is on the findings of the Ukrainian-Polish team of archaeologists who conducted joint excavations at the site in the years 2007–2012. The described fragments of vessels, except for one item, come from the same archaeological context – a residential building discovered in the north-western part of the site dating back to the end of the 5th century – the first half of the 4th century BC. One vessel fragment comes from an earlier phase of the city development dated preliminarily to the second half of the 5th century BC.

Species composition and distribution of commercial penaeid prawn catches in the Gulf of Carpentaria, Australia, in relation to depth and sediment type

1994 ◽  
Vol 45 (3) ◽  
pp. 317 ◽  
Author(s):  
IF Somers
Keyword(s):  
Species Composition ◽  
Species Group ◽  
Individual Species ◽  
Sediment Type ◽  
Muddy Sand ◽  
The North ◽  
North Eastern ◽  
Black Tiger Prawn ◽  
Tiger Prawn ◽  
Catch Statistics

To describe the distribution of the commercial penaeid species caught in the Gulf of Carpentaria, species composition data were drawn from studies conducted in the gulf between 1977 and 1992, supplemented with data from commercial catches monitored by fishers trained in species identification. The catch is made up of eight species in four commercial species groups. Three species account for most of the catch: the banana prawn Penaeus merguiensis (about 41%) and the tiger prawns P. esculentus (24%) and P. semisulcatus (23%). Three others, the endeavour prawns Metapenaeus endeavouri (8%) and M. ensis (3%) and the king prawn P. latisulcatus (1%), are found in commercial quantities but usually as incidental components of catches. Two species, the black tiger prawn, P. monodon, and the red-spot king prawn, P. longistylus, are caught only occasionally. At a fine spatial scale (six-nautical-mile grids), each species group was found to consist largely of just one species, and the ratio of one species to another within a species group were relatively stable over time. By using these ratios in combination with fishers' logbook data, it was possible to refine annual catch statistics for the gulf to the level of species rather than, as in the past, just to species group. The spatial distributions of individual species were found to be related to depth and/or sediment type. Catches of P. merguiensis were mainly from the eastern and southern gulf, and in waters shallower than 20 m, but were not associated with any particular sediment type. The brown tiger prawn, P. esculentus, was most abundant in the southern gulf and shallower parts of the western gulf (< 35 m deep). The sediments in these areas were sand or muddy sand. In contrast, the grooved tiger prawn, P. semisulcatus, was most abundant in the north-eastern gulf and the deeper parts of the western gulf (>35 m deep) where sediments were mud or sandy mud. The blue-tailed endeavour prawn, M. endeavouri, was the most widespread of the species in the gulf, but, like P. esculentus, it was most abundant in the south-eastern gulf and shallower parts of the western gulf, where sediments were either sand or muddy sand. The red endeavour prawn, M. ensis, was more limited in its distribution, with highest abundance in the north-eastern gulf and in the deeper parts of the western gulf (35-45 m). Here, the sediments were more than 60% mud.

scholarly journals Observation of the Emperor penguins Aptenodytes forsteri in the Prince Gustav Channel related with unusual sea-ice decline in north-western Weddell Sea

2019 ◽  
Vol 53 (3) ◽  
pp. 393
Author(s):  
Filip Hrbáček Hrbáček ◽  
Jana Smolíková ◽  
Daniel Nývlt ◽  
Jan Kavan ◽  
Zbyněk Engel
Keyword(s):  
Sea Ice ◽  
Weddell Sea ◽  
Short Paper ◽  
Northern Coast ◽  
The North ◽  
Emperor Penguins ◽  
Observation Area ◽  
Aptenodytes Forsteri ◽  
James Ross Island ◽  
North Western

A pair of juvenile emperor penguins (Aptenodytes forsteri) was observed in the northern coast of James Ross Island, the north-western sector of the Weddell Sea, Antarctica, in January 2017. The penguins originated from the colony located on Snow Hill Island, 120-130 km far from the observation area. Despite the emperor penguin´s ability to migrate over long distances, when they are well-known from different areas in Antarctica, this was the first observation of this species in the north of James Ross Island. In this short paper we discuss the environmental factors which allowed the penguins to reach James Ross Island northern coast, especially significant sea ice variability in this area during last decade.

scholarly journals Analysis of demersal fish assemblages of the Tuscany and Latium coasts (north-western Mediterranean)

2002 ◽  
Vol 66 (S2) ◽  
pp. 233 ◽  
Author(s):  
Franco Biagi ◽  
Paolo Sartor ◽  
Gian Domenico Ardizzone ◽  
Paola Belcari ◽  
Andrea Belluscio ◽  
...  
Keyword(s):  
Species Composition ◽  
Continental Shelf ◽  
Fish Assemblages ◽  
Demersal Fish ◽  
Western Mediterranean ◽  
Similar Species ◽  
The European Union ◽  
The North ◽  
North Western ◽  
Trawl Surveys

A four-year time series (1994-1997) of groundfish trawl surveys performed within the European Union Project MEDITS (Mediterranean International Trawl Surveys), was analysed to identify and describe the fish assemblages along the continental shelf and slope of Tuscany and Latium (Italy), in the north-western Mediterranean. Cluster analysis was used to group samples with similar species composition in terms of abundance, biomass and frequency of occurrence. Results allowed the identification of four to five broad assemblages along the depth gradient: a strictly coastal group (< 50 m depth), two groups in the upper and lower part of the continental shelf (essentially 50-200 m), an epibathyal group (200-450 m) and a group derived from hauls made at depths greater than 450 m. Each assemblage corresponded to a faunistic association with relatively homogeneous and persistent species composition, biomass and density indices.

Sign in / Sign up

Export Citation Format

Share Document